Next Issue
Volume 10, January
Previous Issue
Volume 9, November
 
 
polymers-logo

Journal Browser

Journal Browser

Polymers, Volume 9, Issue 12 (December 2017) – 101 articles

Cover Story (view full-size image): Inspired by nature, polymer chemists have contributed phenomenal endeavors to mimic both structures and functions of natural nucleic acids in synthetic polymers. In this paper, H. Yang and W. Xi deliver the highlights of nucleobase-containing polymers and their applications in materials science. This cover image illustrates how, with the help of powerful polymerization methods, nucleobase-containing monomers in the flask are converted into nucleobase-containing polymers, in which sequence-dependent information is stored. View Paper here.
  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Reader to open them.
Order results
Result details
Section
Select all
Export citation of selected articles as:

Editorial

Jump to: Research, Review, Other

2 pages, 134 KiB  
Editorial
Advanced Control over Cell-Material Interfaces
by João F. Mano 1,* and Insung S. Choi 2,*
1 Department of Chemistry, CICECO—Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal
2 Center for Cell-Encapsulation Research, Department of Chemistry, KAIST, Daejeon 34141, Korea
Polymers 2017, 9(12), 704; https://doi.org/10.3390/polym9120704 - 12 Dec 2017
Cited by 2 | Viewed by 3520
Abstract
Cells in vivo sense and respond to signals from their environment (e.g., other cells and extracellular matrices) for their orchestrated behaviour and function.[...] Full article

Research

Jump to: Editorial, Review, Other

15 pages, 3136 KiB  
Article
Silane Cross-Linked Sulfonted Poly(Ether Ketone/Ether Benzimidazole)s for Fuel Cell Applications
by Zilu Yao, Mengbing Cui, Zhenghui Zhang, Liang Wu and Tongwen Xu *
CAS Key Laboratory of Soft Matter Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials, School of Chemistry and Material Science, University of Science and Technology of China, Hefei 230026, China
Polymers 2017, 9(12), 631; https://doi.org/10.3390/polym9120631 - 23 Nov 2017
Cited by 17 | Viewed by 7286
Abstract
γ-(2,3-epoxypropoxy) propyltrimethoxysilane (KH-560) was incorporated in various proportions into side-chain-type sulfonated poly(ether ketone/ether benzimidazole) (SPEKEBI) as a crosslinker, to make membranes with high ion exchange capacities and excellent performance for direct methanol fuel cells (DMFCs). Systematical measurements including Fourier transform infrared (FT-IR), scanning [...] Read more.
γ-(2,3-epoxypropoxy) propyltrimethoxysilane (KH-560) was incorporated in various proportions into side-chain-type sulfonated poly(ether ketone/ether benzimidazole) (SPEKEBI) as a crosslinker, to make membranes with high ion exchange capacities and excellent performance for direct methanol fuel cells (DMFCs). Systematical measurements including Fourier transform infrared (FT-IR), scanning electron microscopy-energy-dispersive and X-ray photoelectron spectroscopy (XPS) proved the complete disappearance of epoxy groups in KH-560 and the existence of Si in the membranes. The resulting membranes showed increased mechanical strength and thermal stability compared to the unmodified sulfonated poly(ether ketone/ether benzimidazole) membrane in appropriate doping amount. Meanwhile, the methanol permeability has decreased, leading to the increase of relative selectivities of SPEKEBI-x-SiO2 membranes. Furthermore, the H2/O2 cell performance of SPEKEBI-2.5-SiO2 membrane showed a much higher peak power density compared with the pure SPEKEBI memrbrane. Full article
(This article belongs to the Special Issue Polymeric Membranes)
Show Figures

Graphical abstract

12 pages, 1883 KiB  
Article
Microwave Assisted Preparation of Antimicrobial Chitosan with Guanidine Oligomers and Its Application in Hygiene Paper Products
by Junrong Li 1, Ying Ye 1, Huining Xiao 2, Beihai He 1 and Liying Qian 1,*
1 State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China
2 Department of Chemical Engineering, University of New Brunswick, Fredericton, NB E3B 5A3, Canada
Polymers 2017, 9(12), 633; https://doi.org/10.3390/polym9120633 - 24 Nov 2017
Cited by 10 | Viewed by 5083
Abstract
Guanidinylated chitosan (GCS) was prepared by grafting guanidine oligomers onto chitosan under microwave irradiation. The structure of GCS characterized by FT-IR and 1H NMR verified the covalent bonding between the guanidine oligomers and chitosan; the effects of molar ratio, reaction temperature, and [...] Read more.
Guanidinylated chitosan (GCS) was prepared by grafting guanidine oligomers onto chitosan under microwave irradiation. The structure of GCS characterized by FT-IR and 1H NMR verified the covalent bonding between the guanidine oligomers and chitosan; the effects of molar ratio, reaction temperature, and time were investigated and the degree of substitution of GCS reached a maximum of 25.5% under optimized conditions in this work. The resulting GCS showed significantly enhanced antimicrobial activities. The results obtained from the dynamic UV absorption of Escherichia coli (E. coli) and atomic force microscopy (AFM) revealed that the deactivation of E. coli by GCS was due to the destructing of the cell membrane and the prompt release of cytoplasm from the bacterial cells. The adsorption of GCS onto cellulose fibers and the antimicrobial efficiency of the hygiene papers with GCS were also investigated. Microwave irradiation as a green assisted method was applied to promote this reaction. This facile approach allowed chitosan to be guanidinylated without tedious preparation procedures and thus broadened its application as a biocompatible antimicrobial agent. Full article
(This article belongs to the Collection Polysaccharides)
Show Figures

Graphical abstract

22 pages, 3539 KiB  
Article
Prediction of Flow Effect on Crystal Growth of Semi-Crystalline Polymers Using a Multi-Scale Phase-Field Approach
by Xiaodong Wang 1,2,*, Jie Ouyang 2,* and Ying Liu 3,*
1 School of Mathematical Sciences, Peking University, Beijing 100871, China
2 Department of Applied Mathematics, Northwestern Polytechnical University, Xi’an 710129, China
3 School of Arts and Sciences, Shaanxi University of Science & Technology, Xi’an 710021, China
Polymers 2017, 9(12), 634; https://doi.org/10.3390/polym9120634 - 23 Nov 2017
Cited by 5 | Viewed by 5466
Abstract
A multi-scale phase-field approach, which couples the mesoscopic crystallization with the microscopic orientation of chain segments and macroscopic viscoelastic melt flow, is proposed to study how the crystal growth of semi-crystalline polymers is affected by flows. To make the simulation feasible, we divide [...] Read more.
A multi-scale phase-field approach, which couples the mesoscopic crystallization with the microscopic orientation of chain segments and macroscopic viscoelastic melt flow, is proposed to study how the crystal growth of semi-crystalline polymers is affected by flows. To make the simulation feasible, we divide the problem into three parts. In the first part, a finitely extensible nonlinear elastic (FENE) dumbbell model is used to simulate the flow induced molecular structure. In the second part, formulas for estimating the density, orientation and aspect ratio of nuclei upon the oriented molecular structure are derived. Finally, in the third part, a massive mathematical model that couples the phase-field, temperature field, flow field and orientation field is established to model the crystal growth with melt flow. Two-dimensional simulations are carried out for predicting the flow effect on the crystal growth of isotactic polystyrene under a plane Poiseuille flow. In solving the model, a semi-analytical method is adopted to avoid the numerical difficult of a “high Weissenberg number problem” in the first part, and an efficient fractional step method is used to reduce the computing complexity in the third part. The simulation results demonstrate that flow strongly affects the morphology of single crystal but does not bring a significant influence on the holistic morphology of bulk crystallization. Full article
(This article belongs to the Special Issue Phase Behavior in Polymers)
Show Figures

Graphical abstract

16 pages, 5397 KiB  
Article
A Novel Human-Like Collagen Hydrogel Scaffold with Porous Structure and Sponge-Like Properties
by Xi Song 1,2, Chenhui Zhu 1,2, Daidi Fan 1,2,*, Yu Mi 1,2,*, Xian Li 1,2, Rong Zhan Fu 1,2, Zhiguang Duan 1,2, Ya Wang 1,2 and Rui Rui Feng 1,2
1 Shaanxi Key Laboratory of Degradable Biomedical Materials, School of Chemical Engineering, Northwest University, 229 North Taibai Road, Xi’an 710069, China
2 Shaanxi R&D Center of Biomaterials and Fermentation Engineering, School of Chemical Engineering, Northwest University, 229 North Taibai Road, Xi’an 710069, China
Polymers 2017, 9(12), 638; https://doi.org/10.3390/polym9120638 - 13 Dec 2017
Cited by 101 | Viewed by 11390
Abstract
The aim of this research was to prepare a novel sponge-like porous hydrogel scaffold based on human-like collagen (HLC) that could be applied in cartilage tissue regeneration. In this study, bovine serum albumin (BSA) was used as a porogen to prepare the porous [...] Read more.
The aim of this research was to prepare a novel sponge-like porous hydrogel scaffold based on human-like collagen (HLC) that could be applied in cartilage tissue regeneration. In this study, bovine serum albumin (BSA) was used as a porogen to prepare the porous hydrogel, which had not been previously reported. Glutamine transaminase (TGase) was used as the cross-linker of the hydrogel, because it could catalyze the cross-linking of BSA. During the crosslinking process, BSA and HLC were mixed together, which affected the cross-linking of HLC. When the cross-linking was completed, the non-crosslinked section formed pores. The microstructure, porosity, swelling properties, and compressive properties of the hydrogel were studied. The results showed that the pore size of the hydrogel was between 100 and 300 μm, the porosity reached up to 93.43%, and the hydrogel had rapid water absorption and suitable mechanical properties. Finally, we applied the hydrogel to cartilage tissue engineering through in vitro and in vivo research. The in vitro cell experiments suggested that the hydrogel could promote the proliferation and adhesion of chondrocytes, and in vivo transplantation of the hydrogel could enhance the repair of cartilage. In general, the hydrogel is promising as a tissue engineering scaffold for cartilage. Full article
(This article belongs to the Special Issue Hydrogels in Tissue Engineering and Regenerative Medicine)
Show Figures

Graphical abstract

14 pages, 2583 KiB  
Article
Transparent Low Molecular Weight Poly(Ethylene Glycol) Diacrylate-Based Hydrogels as Film Media for Photoswitchable Drugs
by Théophile Pelras 1,2,†, Sarah Glass 1,†, Tom Scherzer 1, Christian Elsner 1, Agnes Schulze 1,* and Bernd Abel 1
1 Leibniz-Institute of Surface Modification, Permoserstraβe 15, 04318 Leipzig, Germany
2 Key Center for Polymers and Colloids, School of Chemistry, University of Sydney, Sydney, NSW 2006, Australia
Both authors contributed equally to this publication.
Polymers 2017, 9(12), 639; https://doi.org/10.3390/polym9120639 - 23 Nov 2017
Cited by 32 | Viewed by 8871
Abstract
Hydrogels have shown a great potential as materials for drug delivery systems thanks to their usually excellent bio-compatibility and their ability to trap water-soluble organic molecules in a porous network. In this study, poly(ethylene glycol)-based hydrogels containing a model dye were synthesized by [...] Read more.
Hydrogels have shown a great potential as materials for drug delivery systems thanks to their usually excellent bio-compatibility and their ability to trap water-soluble organic molecules in a porous network. In this study, poly(ethylene glycol)-based hydrogels containing a model dye were synthesized by ultraviolet (UV-A) photopolymerization of low-molecular weight macro-monomers and the material properties (dye release ability, transparency, morphology, and polymerization kinetics) were studied. Real-time infrared measurements revealed that the photopolymerization of the materials was strongly limited when the dye was added to the uncured formulation. Consequently, the procedure was adapted to allow for the formation of sufficiently cured gels that are able to capture and later on to release dye molecules in phosphate-buffered saline solution within a few hours. Due to the transparency of the materials in the 400–800 nm range, the hydrogels are suitable for the loading and excitation of photoactive molecules. These can be uptaken by and released from the polymer matrix. Therefore, such materials may find applications as cheap and tailored materials in photodynamic therapy (i.e., light-induced treatment of skin infections by bacteria, fungi, and viruses using photoactive drugs). Full article
(This article belongs to the Special Issue Hydrogels in Tissue Engineering and Regenerative Medicine)
Show Figures

Graphical abstract

12 pages, 3939 KiB  
Article
Synthesis and Properties of a Novel Environmental Epoxidized Glycidyl Ester of Ricinoleic Acetic Ester Plasticizer for Poly(vinyl chloride)
by Jie Chen *, Ke Li, Yigang Wang, Jinrui Huang, Xiaoan Nie * and Jianchun Jiang
Institute of Chemical Industry of Forestry Products, Chinese Academy of Forestry, National Engineering Laboratory for Biomass Chemical Utilization, Key Laboratory of Biomass Energy and Material, Nanjing 210042, China
Polymers 2017, 9(12), 640; https://doi.org/10.3390/polym9120640 - 29 Nov 2017
Cited by 35 | Viewed by 9856
Abstract
A novel renewable plasticizer based on castor oil, epoxidized glycidyl ester of ricinoleic acetic ester (EGERAE), was synthesized and applied into Poly(vinyl chloride) (PVC) for the first time. Its molecular structure was characterized by FT-IR and 1H NMR. The effects of replacement [...] Read more.
A novel renewable plasticizer based on castor oil, epoxidized glycidyl ester of ricinoleic acetic ester (EGERAE), was synthesized and applied into Poly(vinyl chloride) (PVC) for the first time. Its molecular structure was characterized by FT-IR and 1H NMR. The effects of replacement of petroleum-based commercial plasticizer dioctyl phthalate (DOP) with EGERAE in poly(vinyl chloride) (PVC) films were researched. Thermal stability, dynamic mechanical property and mechanical properties of PVC films were investigated with thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA) and tensile tests. The results indicated that this castor oil-based plasticizer was able to improve the thermal stability of PVC blends when partially of completely substituting for DOP. Furthermore, EGERAE endowed PVC resin with enhanced flexibility. In addition, the exudation, volatility and extraction resistance characteristics of plasticizers were researched. The degradation mechanism and possible interaction between EGERAE and PVC molecules in the plasticized system were also investigated. Full article
(This article belongs to the Special Issue Green Plasticizers for Polymers)
Show Figures

Graphical abstract

14 pages, 5677 KiB  
Article
Low-Cost Carbon Fillers to Improve Mechanical Properties and Conductivity of Epoxy Composites
by Aamer Khan 1, Patrizia Savi 2,*, Simone Quaranta 3, Massimo Rovere 1, Mauro Giorcelli 1, Alberto Tagliaferro 1, Carlo Rosso 4 and Charles Q. Jia 5
1 Department of Applied Science and Technology (DISAT), Politecnico di Torino, 10129 Torino, Italy
2 Department of Electronics and Telecommunication (DET), Politecnico di Torino, 10129 Torino, Italy
3 Faculty of Science, University of Ontario Institute of Technology (UOIT), Oshawa, ON L1H 7K4, Canada
4 Department of Mechanical and Aerospace Engineering (DIMEAS), Politecnico di Torino, 10129 Torino, Italy
5 Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON M5S 3E5, Canada
Polymers 2017, 9(12), 642; https://doi.org/10.3390/polym9120642 - 24 Nov 2017
Cited by 93 | Viewed by 8728
Abstract
In recent years, low-cost carbons derived from recycled materials have been gaining attention for their potentials as filler in composites and in other applications. The electrical and mechanical properties of polymer composites can be tuned using different percentages and different kind of fillers: [...] Read more.
In recent years, low-cost carbons derived from recycled materials have been gaining attention for their potentials as filler in composites and in other applications. The electrical and mechanical properties of polymer composites can be tuned using different percentages and different kind of fillers: either low-cost (e.g., carbon black), ecofriendly (e.g., biochar), or sophisticated (e.g., carbon nanotubes). In this work, the mechanical and electrical behavior of composites with biochar and multiwall carbon nanotubes dispersed in epoxy resin are compared. Superior mechanical properties (ultimate tensile strength, strain at break) were noticed at low heat-treated biochar (concentrations 2–4 wt %). Furthermore, dielectric properties in the microwave range comparable to low carbon nanotubes loadings can be achieved by employing larger but manageable amounts of biochar (20 wt %), rending the production of composites for structural and functional application cost-effective. Full article
Show Figures

Graphical abstract

9 pages, 8250 KiB  
Article
Preformulation Studies of Furosemide-Loaded Electrospun Nanofibrous Systems for Buccal Administration
by Andrea Kovács 1,3, Balázs Démuth 2, Andrea Meskó 3 and Romána Zelkó 3,*
1 Gedeon Richter Plc., Formulation R&D, Gyömrői Street 19-21, H-1103 Budapest, Hungary
2 Department of Organic Chemistry and Technology, Budapest University of Technology and Economics, Budafoki út 8. 3, H-1103 Budapest, Hungary
3 University Pharmacy Department of Pharmacy Administration, Semmelweis University, Hőgyes Endre Street 7-9, H-1092 Budapest, Hungary
Polymers 2017, 9(12), 643; https://doi.org/10.3390/polym9120643 - 25 Nov 2017
Cited by 10 | Viewed by 5273
Abstract
Furosemide loaded electrospun fibers were prepared for buccal administration, with the aim of improving the oral bioavailability of the poorly soluble and permeable crystalline drug, which can be achieved by the increased solubility and by the circumvention of the intensive first pass metabolism. [...] Read more.
Furosemide loaded electrospun fibers were prepared for buccal administration, with the aim of improving the oral bioavailability of the poorly soluble and permeable crystalline drug, which can be achieved by the increased solubility and by the circumvention of the intensive first pass metabolism. The water soluble hydroxypropyl cellulose (HPC) was chosen as a mucoadhesive polymer. In order to improve the electrospinnability of HPC, poly (vinylpyrrolidone) (PVP) was used. During the experiments, the total polymer concentration was kept constant at 15% (w/w), and only the ratio of the two polymers (HPC-PVP = 5:5, 6:4, 7:3, 8:2, 9:1) was changed. A combination of rheological measurements with scanning electron microscopic morphological images of electrospun samples was applied for the determination of the optimum composition of the gels for fiber formation. The crystalline–amorphous transition of furosemide was tracked by Fourier transform infrared spectroscopy. A correlation was found between the rheological properties of the polymer solutions and their electrospinnability, and the consequent morphology of the resultant samples. With decreasing HPC ratio of the system, a transition from the spray-dried droplets to the randomly oriented fibrous structures was observed. The results enable the determination of the polymer ratio for the formation of applicable quality of electrospun fibers. Full article
Show Figures

Graphical abstract

17 pages, 4903 KiB  
Article
Four Mixed-Ligand Zn(II) Three-Dimensional Metal-Organic Frameworks: Synthesis, Structural Diversity, and Photoluminescent Property
by Chih-Chieh Wang 1,*, Szu-Yu Ke 1, Chia-Wen Cheng 1, Yu-Wen Wang 1, Hsiao-Shan Chiu 1, Yu-Chien Ko 1, Ning-Kuei Sun 1, Mei-Lin Ho 1,*, Chung-Kai Chang 2, Yu-Chun Chuang 2 and Gene-Hsiang Lee 3
1 Department of Chemistry, Soochow University, Taipei 11102, Taiwan
2 National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
3 Instrumentation Center, National Taiwan University, Taipei 10617, Taiwan
Polymers 2017, 9(12), 644; https://doi.org/10.3390/polym9120644 - 25 Nov 2017
Cited by 13 | Viewed by 8313
Abstract
Assemblies of four three-dimensional (3D) mixed-ligand coordination polymers (CPs) having formulas, {[Zn2(bdc)2(4-bpdh)]·C2H5OH·2H2O}n (1), [Zn(bdc)(4-bpdh)]n (2), {[Zn2(bdc)2(4-bpdh)2]·(4-bpdh)}n (3), and [...] Read more.
Assemblies of four three-dimensional (3D) mixed-ligand coordination polymers (CPs) having formulas, {[Zn2(bdc)2(4-bpdh)]·C2H5OH·2H2O}n (1), [Zn(bdc)(4-bpdh)]n (2), {[Zn2(bdc)2(4-bpdh)2]·(4-bpdh)}n (3), and {[Zn(bdc)(4-bpdh)]·C2H5OH}n (4) (bdc2− = dianion of 1,4-benzenedicarboxylic acid, 4-bpdh = 2,5-bis(4-pyridyl)-3,4-diaza-2,4-hexadiene) have been synthesized and structurally characterized by single-crystal X-ray diffraction method. Structural determination reveals that the coordination numbers (geometry) of Zn(II) ions in 1, 2, 3, and 4 are five (distorted square-pyramidal (SP)), six (distorted octahedral (Oh)), five (trigonal-bipyramidal (TBP)), and four (tetrahedral (Td)), respectively, and are bridged by 4-bpdh with bis-monodentate coordination mode and bdc2− ligands with bis-bidentate in 1, chelating/bidentate in 2, bis-monodentate and bis-bidentate in 3, and bis-monodentate in 4, to generate two-fold interpenetrating 3D cube-like metal-organic framework (MOF) with pcu topology, non-interpenetrating 3D MOF, two-fold interpenetrating 3D rectangular-box-like MOF with pcu topology and five-fold interpenetrating diamondoid-like MOF with dia topology, respectively. These different intriguing architectures indicate that the coordination numbers and geometries of Zn(II) ions, coordination modes of bdc2− ligand, and guest molecules play important roles in the construction of MOFs and the formation of the structural topologies and interpenetrations. Thermal stabilities, and photoluminescence study of 14 were also studied in detail. The complexes exhibit ligands based photoluminescence properties at room temperature. Full article
(This article belongs to the Special Issue Coordination Polymer)
Show Figures

Graphical abstract

14 pages, 2964 KiB  
Article
Effect of Zinc Oxide Modified Silica Particles on the Molecular Dynamics of Carboxylated Acrylonitrile-Butadiene Rubber Composites
by Magdalena Gaca 1,*, Joanna Pietrasik 1, Marian Zaborski 1, Lidia Okrasa 2, Gisèle Boiteux 3 and Olivier Gain 3
1 Institute of Polymer and Dye Technology, Lodz University of Technology, Stefanowskiego 12/16, 90-924 Lodz, Poland
2 Department of Molecular Physics, Lodz University of Technology, Zeromskiego 116, 90-924 Lodz, Poland
3 Ingénierie des Matériaux Polymères, Universite Claude Bernard Lyon 1, UMR CNRS 5223, 15 Bd A. Latarjet, 69622 Villeurbanne, France
Polymers 2017, 9(12), 645; https://doi.org/10.3390/polym9120645 - 25 Nov 2017
Cited by 19 | Viewed by 5887
Abstract
This work examines the molecular dynamics of carboxylated acrylonitrile-butadiene rubber crosslinked with zinc oxide modified silica particles. ZnO/SiO2 with the wide range of ZnO concentrations were used as both a crosslinking agent and filler. A series of thermal measurements were applied to [...] Read more.
This work examines the molecular dynamics of carboxylated acrylonitrile-butadiene rubber crosslinked with zinc oxide modified silica particles. ZnO/SiO2 with the wide range of ZnO concentrations were used as both a crosslinking agent and filler. A series of thermal measurements were applied to the characterization of the samples: differential scanning calorimetry, dynamical mechanical thermal analysis, and dielectric relaxation spectroscopy. A complementary experimental technique, which is equilibrium swelling in solvents, confirms the presence of ionic crosslinks, which are created between zinc ions and the functional carboxyl groups of the rubber, within the structure of the vulcanizates. These interactions influenced not only the affinity of the vulcanizates to solvents, but also their dynamic mechanical and dielectric properties. In these investigations, the influence of concentration of ZnO on the surface of the ZnO/SiO2 on the properties of the vulcanizates are described. Full article
(This article belongs to the Collection Silicon-Containing Polymeric Materials)
Show Figures

Graphical abstract

16 pages, 5969 KiB  
Article
Assessment of Polyacrylamide Based Co-Polymers Enhanced by Functional Group Modifications with Regards to Salinity and Hardness
by Saeed Akbari 1,*, Syed Mohammad Mahmood 2,*, Isa M. Tan 3, Hosein Ghaedi 4 and Onn Lin Ling 5
1 Centre of Research in Enhanced Oil Recovery (COREOR), Petroleum Engineering Department, Universiti Teknologi PETRONAS, Seri Iskandar, Tronoh 32610, Malaysia
2 Shale Gas Research Group (SGRG), Institute of Hydrocarbon Recovery, Petroleum Engineering Department, Universiti Teknologi PETRONAS, Seri Iskandar, Tronoh 32610, Malaysia
3 Fundamental and Applied Science, Universiti Teknologi PETRONAS, Seri Iskandar, Tronoh 32610, Malaysia
4 Chemical Engineering Department, Universiti Teknologi PETRONAS, Seri Iskandar, Tronoh 32610, Malaysia
5 Petroleum Engineering Department, Universiti Teknologi PETRONAS, Seri Iskandar, Tronoh 32610, Malaysia
Polymers 2017, 9(12), 647; https://doi.org/10.3390/polym9120647 - 27 Nov 2017
Cited by 53 | Viewed by 11045
Abstract
This research aims to test four new polymers for their stability under high salinity/high hardness conditions for their possible use in polymer flooding to improve oil recovery from hydrocarbon reservoirs. The four sulfonated based polyacrylamide co-polymers were FLOCOMB C7035; SUPERPUSHER SAV55; THERMOASSOCIATIF; and [...] Read more.
This research aims to test four new polymers for their stability under high salinity/high hardness conditions for their possible use in polymer flooding to improve oil recovery from hydrocarbon reservoirs. The four sulfonated based polyacrylamide co-polymers were FLOCOMB C7035; SUPERPUSHER SAV55; THERMOASSOCIATIF; and AN132 VHM which are basically sulfonated polyacrylamide copolymers of AM (acrylamide) with AMPS (2-Acrylamido-2-Methylpropane Sulfonate). AN132 VHM has a molecular weight of 9–11 million Daltons with 32 mol % degree of sulfonation. SUPERPUSHER SAV55 mainly has about 35 mol % sulfonation degree and a molecular weight of 9–11 million Daltons. FLOCOMB C7035, in addition, has undergone post-hydrolysis step to increase polydispersity and molecular weight above 18 million Daltons but it has a sulfonation degree much lower than 32 mol %. THERMOASSOCIATIF has a molecular weight lower than 12 million Daltons and a medium sulfonation degree of around 32 mol %, and also contains LCST (lower critical solution temperature) type block, which is responsible for its thermoassociative characteristics. This paper discusses the rheological behavior of these polymers in aqueous solutions (100–4500 ppm) with NaCl (0.1–10 wt %) measured at 25 °C. The effect of hardness was investigated by preparing a CaCl2-NaCl solution of same ionic strength as the 5 wt % of NaCl. In summary, it can be concluded that the rheological behavior of the newly modified co-polymers was in general agreement to the existing polymers, except that THERMOASSOCIATIF polymers showed unique behavior, which could possibly make them a better candidate for enhanced oil recovery (EOR) application in high salinity conditions. The other three polymers, on the other hand, are better candidates for EOR applications in reservoirs containing high divalent ions. These results are expected to be helpful in selecting and screening the polymers for an EOR application. Full article
Show Figures

Graphical abstract

12 pages, 7410 KiB  
Article
Time Evolution of the Excimer State of a Conjugated Polymer Laser
by Wafa Musa Mujamammi 1, Saradh Prasad 1,2, Mohamad Saleh AlSalhi 1,2 and Vadivel Masilamani 1,2,*
1 Department of Physics and Astronomy, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
2 Research Chair on Laser Diagnosis of Cancers, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
Polymers 2017, 9(12), 648; https://doi.org/10.3390/polym9120648 - 27 Nov 2017
Cited by 8 | Viewed by 4212
Abstract
An excited dimer is an important complex formed in nano- or pico-second time scales in many photophysics and photochemistry applications. The spectral and temporal profile of the excimer state of a laser from a new conjugated polymer, namely, poly (9,9-dioctylfluorenyl-2,7-diyl) (PFO), under several [...] Read more.
An excited dimer is an important complex formed in nano- or pico-second time scales in many photophysics and photochemistry applications. The spectral and temporal profile of the excimer state of a laser from a new conjugated polymer, namely, poly (9,9-dioctylfluorenyl-2,7-diyl) (PFO), under several concentrations in benzene were investigated. These solutions were optically pumped by intense pulsed third-harmonic Nd:YAG laser (355-nm) to obtain the amplified spontaneous emission (ASE) spectra of a monomer and an excimer with bandwidths of 6 and 7 nm, respectively. The monomer and excimer ASEs were dependent on the PFO concentration, pump power, and temperature. Employing a sophisticated picosecond spectrometer, the time evolution of the excimer state of this polymer, which is over 400 ps, can be monitored. Full article
(This article belongs to the Special Issue Polymeric Materials for Optical Applications)
Show Figures

Figure 1

12 pages, 4844 KiB  
Article
Synthesis and Characterization of Dimmer-Acid-Based Nonisocyanate Polyurethane and Epoxy Resin Composite
by Xin He, Xiaoling Xu, Qian Wan, Guangxu Bo and Yunjun Yan *
Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and echnology, Huazhong University of Science and Technology, Wuhan 430074, China
Polymers 2017, 9(12), 649; https://doi.org/10.3390/polym9120649 - 28 Nov 2017
Cited by 24 | Viewed by 7549
Abstract
In this study, dimmer-acid-based hybrid nonisocyanate polyurethanes (HNIPUs) were synthesized by the one-step method without catalyst. Three polyamines and two epoxy resins were selected as raw materials for HNIPU, and cyclic carbonate was synthesized based on our previous work. All of the products [...] Read more.
In this study, dimmer-acid-based hybrid nonisocyanate polyurethanes (HNIPUs) were synthesized by the one-step method without catalyst. Three polyamines and two epoxy resins were selected as raw materials for HNIPU, and cyclic carbonate was synthesized based on our previous work. All of the products were characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). Then, HNIPU coatings were prepared and determined by swelling, water absorption, and water contact angle. The results showed that the HNIPU-4551 have the best mechanical and thermal properties because of its high crosslinking density. Among the different amines, it was confirmed that tetraethylenepentamine was the best amine curing agent for HNIPU coating. Meanwhile, the epoxy resin with a higher epoxy value would also form a higher crosslinking density. Those coatings showed an excellent impact strength, adhesion, flexibility, pencil hardness, hydrophilic, and appropriate crosslinking density. Full article
(This article belongs to the Special Issue Biodegradable and Biobased Polyesters)
Show Figures

Graphical abstract

12 pages, 4240 KiB  
Article
Effect of (Cd:Zn)S Particle Concentration and Photoexcitation on the Electrical and Ferroelectric Properties of (Cd:Zn)S/P(VDF-TrFE) Composite Films
by Sebastian Engel 1, David Smykalla 2, Bernd Ploss 2, Stephan Gräf 1 and Frank A. Müller 1,3,4,*
1 Otto Schott Institute of Materials Research (OSIM), Friedrich Schiller University Jena, Löbdergraben 32, 07743 Jena, Germany
2 Department of SciTec, University of Applied Sciences Jena, Carl-Zeiss-Promenade 2, 07745 Jena, Germany
3 Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743 Jena, Germany
4 Center for Energy and Environmental Chemistry (CEEC), Friedrich Schiller University Jena, Philosophenweg 7a, 07743 Jena, Germany
Polymers 2017, 9(12), 650; https://doi.org/10.3390/polym9120650 - 28 Nov 2017
Cited by 3 | Viewed by 5292
Abstract
The influence of semiconductor particle concentration and photoexcitation on the electrical and ferroelectric properties of ferroelectric-semiconductor-composites was investigated. For this purpose, 32 µm thin films of poly(vinylidene fluoride-co-trifluoroethylene) with (Cd:Zn)S particle concentrations of between 0 and 20 vol % were fabricated [...] Read more.
The influence of semiconductor particle concentration and photoexcitation on the electrical and ferroelectric properties of ferroelectric-semiconductor-composites was investigated. For this purpose, 32 µm thin films of poly(vinylidene fluoride-co-trifluoroethylene) with (Cd:Zn)S particle concentrations of between 0 and 20 vol % were fabricated and characterized by scanning electron microscopy, Fourier transformed infrared spectroscopy, X-ray diffraction, and optical spectroscopy. It was shown that the particle concentration has only a negligible influence on the molecular structure of the polymer but strongly determines the optical properties of the composite. For (Cd:Zn)S particle concentrations below 20 vol %, the I-V characteristics of the composites is only marginally affected by the particle concentration and the optical excitation of the composite material. On the contrary, a strong influence of both parameters on the ferro- and pyroelectric properties of the composite films was observed. For particle fractions that exhibit ferroelectric hysteresis, an increased remanent polarization and pyroelectric coefficient due to optical excitation was obtained. A theoretical approach that is based on a “three phase model” of the internal structure was developed to explain the observed results. Full article
(This article belongs to the Special Issue Fluorinated Polymers)
Show Figures

Figure 1

15 pages, 13399 KiB  
Article
Long-Term Durability of Basalt Fiber-Reinforced Polymer (BFRP) Sheets and the Epoxy Resin Matrix under a Wet–Dry Cyclic Condition in a Chloride-Containing Environment
by Zhongyu Lu, Jianhe Xie *, Huan Zhang and Jianglin Li
School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, China
Polymers 2017, 9(12), 652; https://doi.org/10.3390/polym9120652 - 28 Nov 2017
Cited by 51 | Viewed by 7094
Abstract
Basalt fiber-reinforced polymer (BFRP) composites are receiving increasing attention as they represent a low-cost green source of raw materials. FRP composites have to face harsh environments, such as chloride ions in coastal marine environments or cold regions with salt deicing. The resistance of [...] Read more.
Basalt fiber-reinforced polymer (BFRP) composites are receiving increasing attention as they represent a low-cost green source of raw materials. FRP composites have to face harsh environments, such as chloride ions in coastal marine environments or cold regions with salt deicing. The resistance of FRPs subjected to the above environments is critical for the safe design and application of BFRP composites. In the present paper, the long-term durability of BFRP sheets and the epoxy resin matrix in a wet–dry cyclic environment containing chloride ions was studied. The specimens of the BFRP sheet and epoxy resin matrix were exposed to alternative conditions of 8-h immersion in 3.5% NaCl solution at 40 °C and 16-h drying at 25 °C and 60% relative humidity (RH). The specimens were removed from the exposure chamber at the end of the 180th, 270th and 360th cycles of exposure and were analyzed for degradation with tensile tests, scanning electron microscopy (SEM) and void volume fractions. It was found that the tensile modulus of the BFRP sheet increased by 3.4%, and the tensile strength and ultimate strain decreased by 45% and 65%, respectively, after the 360th cycle of exposure. For the epoxy resin matrix, the tensile strength, tensile modulus and ultimate strain decreased by 27.8%, 3.2% and 64.8% after the 360th cycle of exposure, respectively. The results indicated that the degradation of the BFRP sheet was dominated by the damage of the interface between the basalt fiber and epoxy resin matrix. In addition, salt precipitate accelerated the fiber–matrix interfacial debonding, and hydrolysis of the epoxy resin matrix resulted in many voids, which accelerated the degradation of the BFRP sheet. Full article
Show Figures

Figure 1

18 pages, 3918 KiB  
Article
The Multi-Template Molecularly Imprinted Polymer Based on SBA-15 for Selective Separation and Determination of Panax notoginseng Saponins Simultaneously in Biological Samples
by Chenghong Sun 1,†, Jinhua Wang 2,†, Jiaojiao Huang 1, Dandan Yao 1, Chong-Zhi Wang 3, Lei Zhang 1, Shuying Hou 2,*, Lina Chen 1,* and Chun-Su Yuan 3
1 School of Pharmacy, Nanjing Medical University, Nanjing 211166, China
2 Department of Pharmacy Intravenous Admixture Service, The First Affiliated Hospital of Harbin Medical University, Harbin 150001, China
3 Tang Center for Herbal Medicine Research and Department of Anesthesia & Critical Care, University of Chicago, Chicago, IL 60637, USA
These authors contributed equally to this work.
Polymers 2017, 9(12), 653; https://doi.org/10.3390/polym9120653 - 28 Nov 2017
Cited by 19 | Viewed by 6825
Abstract
The feasible, reliable and selective multi-template molecularly imprinted polymers (MT-MIPs) based on SBA-15 (SBA-15@MT-MIPs) for the selective separation and determination of the trace level of ginsenoside Rb1 (Rb1), ginsenoside Rg1 (Rg1) and notoginsenoside R1 (R1 [...] Read more.
The feasible, reliable and selective multi-template molecularly imprinted polymers (MT-MIPs) based on SBA-15 (SBA-15@MT-MIPs) for the selective separation and determination of the trace level of ginsenoside Rb1 (Rb1), ginsenoside Rg1 (Rg1) and notoginsenoside R1 (R1) simultaneously from biological samples were developed. The polymers were constructed by SBA-15 as support, Rb1, Rg1, R1 as multi-template, acrylamide (AM) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as cross-linker. The new synthetic SBA-15@MT-MIPs were satisfactorily applied to solid-phase extraction (SPE) coupled with high performance liquid chromatography (HPLC) for the separation and determination of trace Rb1, Rg1 and R1 in plasma samples. Under the optimized conditions, the limits of detection (LODs) and quantitation (LOQs) of the proposed method for Rb1, Rg1 and R1 were in the range of 0.63–0.75 ng·mL−1 and 2.1–2.5 ng·mL−1, respectively. The recoveries of R1, Rb1 and Rg1 were obtained between 93.4% and 104.3% with relative standard deviations (RSDs) in the range of 3.3–4.2%. All results show that the obtained SBA-15@MT-MIPs could be a promising prospect for the practical application in the selective separation and enrichment of trace Panax notoginseng saponins (PNS) in the biological samples. Full article
(This article belongs to the Special Issue Molecularly Imprinted Polymers)
Show Figures

Graphical abstract

15 pages, 3675 KiB  
Article
Poly(piperazine-amide)/PES Composite Multi-Channel Capillary Membranes for Low-Pressure Nanofiltration
by Jan O. Back 1, Martin Spruck 1, Marc Koch 1, Lukas Mayr 2, Simon Penner 2 and Marco Rupprich 1,*
1 Management Center Innsbruck (MCI)—The Entrepreneurial School, Department of Environmental, Process & Energy Engineering, Maximilianstrasse 2, 6020 Innsbruck, Austria
2 Institute of Physical Chemistry, University of Innsbruck, Innrain 52c, 6020 Innsbruck, Austria
Polymers 2017, 9(12), 654; https://doi.org/10.3390/polym9120654 - 28 Nov 2017
Cited by 9 | Viewed by 7592
Abstract
The mechanical stability of conventional single-channel capillary fibres can be improved in a multi-channel geometry, which has previously found application in ultrafiltration. In this work, multi-channel polyethersulfone (PES) capillary membranes comprising seven feed channels were successfully fabricated in an enhanced steam–dry–wet spinning process [...] Read more.
The mechanical stability of conventional single-channel capillary fibres can be improved in a multi-channel geometry, which has previously found application in ultrafiltration. In this work, multi-channel polyethersulfone (PES) capillary membranes comprising seven feed channels were successfully fabricated in an enhanced steam–dry–wet spinning process and coated on the inner surface with a thin polyamide (PA) layer via interfacial polymerization (IP). The coating procedure consisted of impregnating the support multi-channel capillary membranes (MCM) with an aqueous piperazine solution, flushing with nitrogen gas to remove excess droplets, and pumping an organic trimesoylchloride solution through the channels. Insights into the interfacial polymerization process were gained through the investigation of various parameters, including monomer ratio, contact time, and drying time. Membranes were characterised via scanning electron microscopy (SEM), atomic force microscopy (AFM), and filtration experiments. The optimisation of both the PES support membrane and IP process parameters allowed for the fabrication of composite MCM with an MgSO4 rejection of 91.4% and a solute flux of 68.8 L m−2 h−1 at an applied pressure of 3 bar. The fabricated composite MCM demonstrates that a favourable multi-channel arrangement can be upgraded with a PA layer for application in low-pressure nanofiltration. Full article
(This article belongs to the Special Issue Polymeric Membranes)
Show Figures

Graphical abstract

16 pages, 4469 KiB  
Article
Biomimetically Reinforced Polyvinyl Alcohol-Based Hybrid Scaffolds for Cartilage Tissue Engineering
by Hwan D. Kim 1,†, Yunsup Lee 1,†, Yunhye Kim 2,3, Yongsung Hwang 2,3,* and Nathaniel S. Hwang 1,4,*
1 School of Chemical and Biological Engineering, the Institute of Chemical Processes, Seoul National University, Seoul 08826, Korea
2 Soonchunhyang Institute of Medi-Bio Science (SIMS), Soonchunhyang University, Cheonan-si, Chungcheongnam-do 31151, Korea
3 Institute of Tissue Regeneration, College of Medicine, Soonchunhyang University, Cheonan-si, Chungcheongnam-do 31151, Korea
4 The BioMax Institute of Seoul National University, Seoul 08826, Korea
These authors contributed equally to this work.
Polymers 2017, 9(12), 655; https://doi.org/10.3390/polym9120655 - 28 Nov 2017
Cited by 34 | Viewed by 9918
Abstract
Articular cartilage has a very limited regeneration capacity. Therefore, injury or degeneration of articular cartilage results in an inferior mechanical stability, load-bearing capacity, and lubrication capability. Here, we developed a biomimetic scaffold consisting of macroporous polyvinyl alcohol (PVA) sponges as a platform material [...] Read more.
Articular cartilage has a very limited regeneration capacity. Therefore, injury or degeneration of articular cartilage results in an inferior mechanical stability, load-bearing capacity, and lubrication capability. Here, we developed a biomimetic scaffold consisting of macroporous polyvinyl alcohol (PVA) sponges as a platform material for the incorporation of cell-embedded photocrosslinkable poly(ethylene glycol) diacrylate (PEGDA), PEGDA-methacrylated chondroitin sulfate (PEGDA-MeCS; PCS), or PEGDA-methacrylated hyaluronic acid (PEGDA-MeHA; PHA) within its pores to improve in vitro chondrocyte functions and subsequent in vivo ectopic cartilage tissue formation. Our findings demonstrated that chondrocytes encapsulated in PCS or PHA and loaded into macroporous PVA hybrid scaffolds maintained their physiological phenotypes during in vitro culture, as shown by the upregulation of various chondrogenic genes. Further, the cell-secreted extracellular matrix (ECM) improved the mechanical properties of the PVA-PCS and PVA-PHA hybrid scaffolds by 83.30% and 73.76%, respectively, compared to their acellular counterparts. After subcutaneous transplantation in vivo, chondrocytes on both PVA-PCS and PVA-PHA hybrid scaffolds significantly promoted ectopic cartilage tissue formation, which was confirmed by detecting cells positively stained with Safranin-O and for type II collagen. Consequently, the mechanical properties of the hybrid scaffolds were biomimetically reinforced by 80.53% and 210.74%, respectively, compared to their acellular counterparts. By enabling the recapitulation of biomimetically relevant structural and functional properties of articular cartilage and the regulation of in vivo mechanical reinforcement mediated by cell–matrix interactions, this biomimetic material offers an opportunity to control the desired mechanical properties of cell-laden scaffolds for cartilage tissue regeneration. Full article
(This article belongs to the Special Issue Hydrogels in Tissue Engineering and Regenerative Medicine)
Show Figures

Graphical abstract

18 pages, 6255 KiB  
Article
The Availability of Neutral Cyan, Green, Blue and Purple Colors from Simple D–A Type Polymers with Commercially Available Thiophene Derivatives as the Donor Units
by Lingqian Kong 1,2, Min Wang 3, Xiuping Ju 1, Jinsheng Zhao 2,*, Yan Zhang 2 and Yu Xie 4,*
1 Dongchang College, Liaocheng University, Liaocheng 252059, China
2 Department of Chemistry, Liaocheng University, Liaocheng 252059, China
3 Liaocheng People’s Hospital, Liaocheng 252000, China
4 College of Environment and Chemical Engineering, Nanchang Hangkong University, Nanchang 330063, China
Polymers 2017, 9(12), 656; https://doi.org/10.3390/polym9120656 - 29 Nov 2017
Cited by 13 | Viewed by 5504
Abstract
In this paper, the Stille coupling reaction was used to prepare four donor–acceptor–donor (D–A–D) type monomers. For this purpose, 2,3-bis(4-methoxyphenyl) quinoxaline was used as the acceptor unit, and thiophene derivatives (3,4-ethylenedioxythiophene, or EDOT; 3-methoxythiophene, or MOTh; 3-methylthiophene, or MTh; and thiophene, or Th) [...] Read more.
In this paper, the Stille coupling reaction was used to prepare four donor–acceptor–donor (D–A–D) type monomers. For this purpose, 2,3-bis(4-methoxyphenyl) quinoxaline was used as the acceptor unit, and thiophene derivatives (3,4-ethylenedioxythiophene, or EDOT; 3-methoxythiophene, or MOTh; 3-methylthiophene, or MTh; and thiophene, or Th) were used as the donor units. The monomers were polymerized to the corresponding polymers by the cyclic voltammetry (CV) or potentiostatic method. The band gaps and the adsorption profiles of the polymers were finely tuned with the incorporation of the different thiophene units. All four polymers have low band gaps, and switched between the colored neutral states and the highly transmissive oxidized state. We were successfully able to obtain the valuable neutral colors of cyan, green, blue, and violet for the polymers employing EDOT, MOTh, MTh, and Th as the donor unit, respectively. Furthermore, electrochromic kinetic investigations showed that all four polymers displayed excellent optical contrasts (ΔT%), fast switching times, high coloration efficiencies, and robust stabilities, indicating that these four polymers are probably promising choices for developing electrochromic devices. Full article
(This article belongs to the Special Issue Polymeric Materials for Optical Applications)
Show Figures

Graphical abstract

10 pages, 1496 KiB  
Article
Molecular Spring Enabled High-Performance Anode for Lithium Ion Batteries
by Tianyue Zheng 1,†, Zhe Jia 1,†, Na Lin 2, Thorsten Langer 3, Simon Lux 4, Isaac Lund 4, Ann-Christin Gentschev 4, Juan Qiao 2 and Gao Liu 1,*
1 Energy Storage and Distributed Resources Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd., Berkeley, CA 94720, USA
2 Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing 100084, China
3 BMW Group, Petuelring 130, 80788 Munich, Germany
4 BMW Group Technology Office USA, 2606 Bayshore Parkway, Mountain View, CA 94043, USA
These authors contributed equally to this work.
Polymers 2017, 9(12), 657; https://doi.org/10.3390/polym9120657 - 29 Nov 2017
Cited by 17 | Viewed by 7888
Abstract
Flexible butyl interconnection segments are synthetically incorporated into an electronically conductive poly(pyrene methacrylate) homopolymer and its copolymer. The insertion of butyl segment makes the pyrene polymer more flexible, and can better accommodate deformation. This new class of flexible and conductive polymers can be [...] Read more.
Flexible butyl interconnection segments are synthetically incorporated into an electronically conductive poly(pyrene methacrylate) homopolymer and its copolymer. The insertion of butyl segment makes the pyrene polymer more flexible, and can better accommodate deformation. This new class of flexible and conductive polymers can be used as a polymer binder and adhesive to facilitate the electrochemical performance of a silicon/graphene composite anode material for lithium ion battery application. They act like a “spring” to maintain the electrode mechanical and electrical integrity. High mass loading and high areal capacity, which are critical design requirements of high energy batteries, have been achieved in the electrodes composed of the novel binders and silicon/graphene composite material. A remarkable area capacity of over 5 mAh/cm2 and volumetric capacity of over 1700 Ah/L have been reached at a high current rate of 333 mA/g. Full article
(This article belongs to the Special Issue Conductive Polymers 2017)
Show Figures

Figure 1

9 pages, 7648 KiB  
Article
High Throughput Preparation of Aligned Nanofibers Using an Improved Bubble-Electrospinning
by Liang Yu 1, Zhongbiao Shao 1, Lan Xu 1,* and Mingdi Wang 2,*
1 National Engineering Laboratory for Modern Silk, College of Textile and Engineering, Soochow University, 199 Ren-ai Road, Suzhou 215123, China
2 School of Mechanical and Electric Engineering, Soochow University, 178 Ganjiang Road, Suzhou 215021, China
Polymers 2017, 9(12), 658; https://doi.org/10.3390/polym9120658 - 29 Nov 2017
Cited by 48 | Viewed by 5792
Abstract
An improved bubble-electrospinning, consisting of a cone shaped air nozzle, a copper solution reservoir connected directly to the power generator, and a high speed rotating copper wire drum as a collector, was presented successfully to obtain high throughput preparation of aligned nanofibers. The [...] Read more.
An improved bubble-electrospinning, consisting of a cone shaped air nozzle, a copper solution reservoir connected directly to the power generator, and a high speed rotating copper wire drum as a collector, was presented successfully to obtain high throughput preparation of aligned nanofibers. The influences of drum rotation speed on morphology and properties of obtained nanofibers were explored and researched. The results showed that the alignment degree, diameter distribution, and properties of nanofibers were improved with the increase of the drum rotation speed. Full article
(This article belongs to the Special Issue Electrospinning of Nanofibres)
Show Figures

Graphical abstract

13 pages, 2691 KiB  
Article
Simple and High Yield Synthesis of Metal-Polymer Nanocomposites: The Role of Theta-Centrifugation as an Essential Purification Step
by Patrick Hummel 1, Arne Lerch 2, Sebastian Manfred Goller 1, Matthias Karg 2 and Markus Retsch 1,*
1 Department of Chemistry, University of Bayreuth, Universitätsstr. 30, 95447 Bayreuth, Germany
2 Physical Chemistry I, Heinrich-Heine-University Düsseldorf, Universitätsstr. 1, 40204 Düsseldorf, Germany
Polymers 2017, 9(12), 659; https://doi.org/10.3390/polym9120659 - 30 Nov 2017
Cited by 9 | Viewed by 7040
Abstract
Nanocomposites are an important materials class, which strives to foster synergistic effects from the intimate mixture of two vastly different materials. Inorganic nanoparticles decorated with polymer ligands, for instance, aim to combine the processing flexibility of polymers with the mechanical robustness of solid [...] Read more.
Nanocomposites are an important materials class, which strives to foster synergistic effects from the intimate mixture of two vastly different materials. Inorganic nanoparticles decorated with polymer ligands, for instance, aim to combine the processing flexibility of polymers with the mechanical robustness of solid state materials. The fabrication and purification of such composite nanoparticles, however, still presents a synthetic challenge. Here, we present a simple synthesis of silver polystyrene nanocomposites with a controllable interparticle distance. The interparticle distance can be well-controlled with a few nanometer precision using polystyrene ligands with various molecular weights. The nanoparticle and polymer ligand synthesis yield both materials on gram scales. Consequently, the polymer nanocomposites can also be fabricated in such large amounts. Most importantly, we introduce Θ-centrifugation as a purification method, which is capable of purifying large nanocomposite batches in a reproducible manner. We employ a range of characterization methods to prove the successful purification procedure, such as transmission electron microscopy, thermogravimetric analysis, and dynamic light scattering. Our contribution will be of high interest for many groups working on nanocomposite materials, where the sample purification has been a challenge up to now. Full article
(This article belongs to the Special Issue Polymers and Block Copolymers at Interfaces and Surfaces)
Show Figures

Graphical abstract

17 pages, 4473 KiB  
Article
Coating of TPU-PDMS-TMS on Polycotton Fabrics for Versatile Protection
by Arsheen Moiz, Rajiv Padhye and Xin Wang *
School of Fashion and Textiles, RMIT University, Melbourne 3056, Australia
Polymers 2017, 9(12), 660; https://doi.org/10.3390/polym9120660 - 30 Nov 2017
Cited by 43 | Viewed by 11094
Abstract
This research aims to develop a non-fluorine based and durable coating technology that brings excellent hydrophobic, oleophobic and aqueous liquid repellent properties to polycotton fabrics (blend ratio 80/20 for cotton/polyester) while maintaining comfort to an acceptable level. A crosslinked network from thermoplastic polyurethane [...] Read more.
This research aims to develop a non-fluorine based and durable coating technology that brings excellent hydrophobic, oleophobic and aqueous liquid repellent properties to polycotton fabrics (blend ratio 80/20 for cotton/polyester) while maintaining comfort to an acceptable level. A crosslinked network from thermoplastic polyurethane (TPU), polydimethylsiloxane (PDMS) and trimethylated silica (TMS) has been formed on the surface of polycotton fabrics by the conventional padding-knife coating-padding-curing technique. A series of characterizations have been conducted to understand the chemical components, morphology, versatile protection and comfort of the coated fabrics. The TPU-PDMS-TMS (TPT) coated fabrics showed a high hydrophobic surface with a high water contact angle of 142°, and the coating was durable against different cycles of laundering and crocking. The coated fabrics also showed excellent repellency against oils, liquids and chemicals for a long period of time. The coating has affected the air permeability and water vapor permeability together with the moisture management property of the polycotton fabrics, and the thermal resistance of the polycotton fabric has been enhanced at the same time. The coating technology developed can be further applied in protective clothing and functional textiles in different areas including military, mining and outdoor protection gear. Full article
(This article belongs to the Special Issue Textile and Textile-Based Materials)
Show Figures

Graphical abstract

11 pages, 2016 KiB  
Article
Synthesis, Structure, and Dye Adsorption Properties of a Nickel(II) Coordination Layer Built from d-Camphorate and Bispyridyl Ligands
by Meng-Jung Tsai and Jing-Yun Wu *
Department of Applied Chemistry, National Chi Nan University, Nantou 545, Taiwan
Polymers 2017, 9(12), 661; https://doi.org/10.3390/polym9120661 - 30 Nov 2017
Cited by 26 | Viewed by 5303
Abstract
Reaction of NiCl2∙6H2O, d-camphoric acid (d-H2cam), and N,N′-bis(pyraz-2-yl)piperazine (bpzpip) in pure water at 150 °C afforded a novel nickel(II) coordination layer, [Ni4(d-cam)2(d-Hcam)4 [...] Read more.
Reaction of NiCl2∙6H2O, d-camphoric acid (d-H2cam), and N,N′-bis(pyraz-2-yl)piperazine (bpzpip) in pure water at 150 °C afforded a novel nickel(II) coordination layer, [Ni4(d-cam)2(d-Hcam)4(bpzpip)4(H2O)2] (1), under hydro(solvo)thermal conditions. Single-crystal X-ray structure analysis reveals that 1 adopts a six-connected two-dimensional (2D) chiral layer structure with 36-hxl topology. Dye adsorption explorations indicate that 1 readily adsorbs methyl blue (MyB) from water without destruction of crystallinity. On the contrary, methyl orange (MO) is not adsorbed at all. The pseudo-second-order kinetic model could be used to interpret the adsorption kinetics for MyB. Equilibrium isotherm studies suggest complicated adsorption processes for MyB which do not have good applicability for either the two-parameter Langmuir or Freundlich isotherm model. The saturated adsorption capacity of 1 for MyB calculated by Langmuir is 185.5 mg·g−1 at room temperature. Full article
(This article belongs to the Special Issue Coordination Polymer)
Show Figures

Graphical abstract

11 pages, 3556 KiB  
Article
Highly Conductive 3D Segregated Graphene Architecture in Polypropylene Composite with Efficient EMI Shielding
by Fakhr E. Alam 1,2, Jinhong Yu 1,*, Dianyu Shen 1, Wen Dai 1,2, He Li 1,2, Xiaoliang Zeng 3, Yagang Yao 4, Shiyu Du 5, Nan Jiang 1,* and Cheng-Te Lin 1,2,*
1 Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering (NIMTE), Chinese Academy of Sciences, Ningbo 315201, China
2 University of Chinese Academy of Sciences, 19 A Yuquan Rd., Shijingshan District, Beijing 100049, China
3 Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
4 Division of Advanced Nanomaterials, Key Laboratory of Nanodevices and Applications, CAS Center for Excellence in Nanoscience, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Suzhou 215123, China
5 Division of Functional Materials and Nanodevices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China
Polymers 2017, 9(12), 662; https://doi.org/10.3390/polym9120662 - 2 Dec 2017
Cited by 45 | Viewed by 7622
Abstract
The extensive use of electronic equipment in modern life causes potential electromagnetic pollution harmful to human health. Therefore, it is of great significance to enhance the electrical conductivity of polymers, which are widely used in electronic components, to screen out electromagnetic waves. The [...] Read more.
The extensive use of electronic equipment in modern life causes potential electromagnetic pollution harmful to human health. Therefore, it is of great significance to enhance the electrical conductivity of polymers, which are widely used in electronic components, to screen out electromagnetic waves. The fabrication of graphene/polymer composites has attracted much attention in recent years due to the excellent electrical properties of graphene. However, the uniform distribution of graphene nanoplatelets (GNPs) in a non-polar polymer matrix like polypropylene (PP) still remains a challenge, resulting in the limited improvement of electrical conductivity of PP-based composites achieved to date. Here, we propose a single-step approach to prepare GNPs/PP composites embedded with a segregated architecture of GNPs by coating PP particles with GNPs, followed by hot-pressing. As a result, the electrical conductivity of 10 wt % GNPs-loaded composites reaches 10.86 S·cm−1, which is ≈7 times higher than that of the composites made by the melt-blending process. Accordingly, a high electromagnetic interference shielding effectiveness (EMI SE) of 19.3 dB can be achieved. Our method is green, low-cost, and scalable to develop 3D GNPs architecture in a polymer matrix, providing a versatile composite material suitable for use in electronics, aerospace, and automotive industries. Full article
(This article belongs to the Special Issue Conductive Polymers 2017)
Show Figures

Graphical abstract

16 pages, 3931 KiB  
Article
Environmentally-Friendly Synthesis of Carbonate-Type Macrodiols and Preparation of Transparent Self-Healable Thermoplastic Polyurethanes
by Seon-Mi Kim 1,†, Seul-A Park 1,†, Sung Yeon Hwang 1,2, Eun Seon Kim 1, Jonggeon Jegal 1, Changgyu Im 3, Hyeonyeol Jeon 1,*, Dongyeop X. Oh 1,2,* and Jeyoung Park 1,2,*
1 Research Center for Bio-Based Chemistry, Korea Research Institute of Chemical Technology (KRICT), Ulsan 44429, Korea
2 Advanced Materials and Chemical Engineering, University of Science and Technology (UST), Daejeon 34113, Korea
3 Department of Chemical Engineering, Hanyang University, Ansan 15588, Korea
These authors contributed equally to this work.
Polymers 2017, 9(12), 663; https://doi.org/10.3390/polym9120663 - 30 Nov 2017
Cited by 28 | Viewed by 8327
Abstract
Carbonate-type macrodiols synthesized by base-catalyzed polycondensation of co-diols and dimethyl carbonate as an environmentally-friendly route were subsequently utilized for the preparation of transparent and self-healable thermoplastic polyurethanes (TPUs) containing a carbonate-type soft segment. Three types of macrodiols, obtained from mono, dual and triple [...] Read more.
Carbonate-type macrodiols synthesized by base-catalyzed polycondensation of co-diols and dimethyl carbonate as an environmentally-friendly route were subsequently utilized for the preparation of transparent and self-healable thermoplastic polyurethanes (TPUs) containing a carbonate-type soft segment. Three types of macrodiols, obtained from mono, dual and triple diol-monomers for target molecular weights of 1 and 1.5 kg mol−1, were analyzed by 1H NMR integration and the OH titration value. Colorless transparent macrodiols in a liquid state at a room temperature of 20 °C were obtained, except the macrodiol from mono 1,6-hexanediol. Before TPU synthesis, macrodiols require pH neutralization to prevent gelation. TPUs synthesized by a solution pre-polymer method with 4,4′-methylene(bisphenyl isocyanate) and 1,4-butanediol as a chain extender exhibited moderate molecular weights, good transparencies and robust mechanical properties. Especially, the incorporation of 3-methyl-1,5-pentanediol within carbonate-type macrodiols enhanced the transparency of the resultant TPUs by decreasing the degree of microphase separation evidenced by ATR-FTIR and DSC. Interestingly, packing density of hard segments and the degree of microphase separation determined the self-healing efficiency of TPUs, which showed good performances in the case of sourced macrodiols from triple diol-monomers. Full article
Show Figures

Graphical abstract

13 pages, 1013 KiB  
Article
Design Analysis of Adhesively Bonded Structures
by Ee-Hua Wong 1,2,* and Johan Liu 3,4
1 Sino-Singapore International Joint Research Institute, Guangzhou 510550, China
2 Energy Research Institute, Nanyang Technological University, Nanyang 639798, Singapore
3 Microtechnology and Nanoscience, Chalmers University of Technology, Gothenburg Se41296, Sweden
4 SMIT Center, Shanghai University, No 20, Chengzhong Road, Shanghai 201800, China
Polymers 2017, 9(12), 664; https://doi.org/10.3390/polym9120664 - 1 Dec 2017
Cited by 9 | Viewed by 4292
Abstract
The existing analytical solutions for the peeling and shearing stresses in polymeric adhesively bonded structures are either too inaccurate or too complex for adoption by practicing engineers. This manuscript presents a closed-form solution that is reasonably accurate yet simple and concise enough to [...] Read more.
The existing analytical solutions for the peeling and shearing stresses in polymeric adhesively bonded structures are either too inaccurate or too complex for adoption by practicing engineers. This manuscript presents a closed-form solution that is reasonably accurate yet simple and concise enough to be adopted by practicing engineers for design analysis and exploration. Analysis of these concise solutions have yielded insightful design guidelines: (i) the magnitude of peeling stress is generally higher than that of shearing stress; (ii) the peeling stress in a balanced structure may be reduced most effectively by reducing the elastic modulus of the adherends or by increasing the adhesive-to-adherend thickness ratio and less effectively by reducing the elastic modulus of the adhesive; and (iii) the peeling stress in an unbalanced structure may be reduced by increasing the in-plane compliance of the structure, which may be implemented most effectively by reducing the thicknesses of the adherends and less effectively by reducing the elastic modulus of the adherends. Full article
(This article belongs to the Collection Polymeric Adhesives)
Show Figures

Graphical abstract

13 pages, 3184 KiB  
Article
Effect of Cross-Linking on the Performances of Starch-Based Biopolymer as Gel Electrolyte for Dye-Sensitized Solar Cell Applications
by Pavithra Nagaraj 1, Asija Sasidharan 1, Velayutham David 2 and Anandan Sambandam 1,*
1 Nanomaterials and Solar Energy Conversion Lab, Department of Chemistry, National Institute of Technology, Tiruchirappalli 620 015, India
2 Electro Organic Division, CSIR-Central Electrochemical Research Institute, Karaikudi 630 006, India
Polymers 2017, 9(12), 667; https://doi.org/10.3390/polym9120667 - 1 Dec 2017
Cited by 47 | Viewed by 9797
Abstract
Dye-sensitized solar cells (DSSCs) have become a validated and economically credible competitor to the traditional solid-state junction photovoltaic devices. DSSCs based on biopolymer gel electrolyte systems offer the perspective of competitive conversion efficiencies with a very low-cost fabrication. In this paper, a new [...] Read more.
Dye-sensitized solar cells (DSSCs) have become a validated and economically credible competitor to the traditional solid-state junction photovoltaic devices. DSSCs based on biopolymer gel electrolyte systems offer the perspective of competitive conversion efficiencies with a very low-cost fabrication. In this paper, a new starch-based biopolymer gel electrolyte system is prepared by mixing lithium iodide and iodine with bare and citric acid cross-linked potato starches with glycerol as the plasticizing agent. The effect of the preparation methods on the starch cross-linking degree as well as the photoconversion efficiency of the resulting DSSC cells is carefully analyzed. Fourier transform spectroscopy, X-ray diffraction, and scanning electron microscopy were used to characterize the morphology and conformational changes of starch in the electrolytes. The conductivity of the biopolymer electrolytes was determined by electrochemical impedance spectroscopy. DSSC based on the starch-gel polymer electrolytes were characterized by photovoltaic measurements and electrochemical impedance spectroscopy. Results clearly show that the cross-linking increases the recombination resistance and open circuit voltage (VOC) of the DSSC, and thereby the photoconversion efficiency of the cell. In particular, electrolytes containing 1.4 g bare and cross-linked starches showed ionic conductivities of σ = 1.61, 0.59, 0.38, and 0.35 S cm−1, and the corresponding DSSCs showed efficiencies of 1.2, 1.4, 0.93, and 1.11%, respectively. Full article
(This article belongs to the Collection Polysaccharides)
Show Figures

Graphical abstract

23 pages, 3450 KiB  
Article
Surfactant-Free RAFT Emulsion Polymerization of Styrene Using Thermoresponsive macroRAFT Agents: Towards Smart Well-Defined Block Copolymers with High Molecular Weights
by Steffen Eggers 1 and Volker Abetz 1,2,*
1 Department of Physical Chemistry, University of Hamburg, Grindelallee 117, 20146 Hamburg, Germany
2 Institute of Polymer Research, Helmholtz-Zentrum Geesthacht, Max-Planck-Straße 1, 21502 Geesthacht, Germany
Polymers 2017, 9(12), 668; https://doi.org/10.3390/polym9120668 - 3 Dec 2017
Cited by 17 | Viewed by 9994
Abstract
The combination of reversible addition–fragmentation chain transfer (RAFT) and emulsion polymerization has recently attracted much attention as a synthetic tool for high-molecular-weight block copolymers and their micellar nano-objects. Up to recently, though, the use of thermoresponsive polymers as both macroRAFT agents and latex [...] Read more.
The combination of reversible addition–fragmentation chain transfer (RAFT) and emulsion polymerization has recently attracted much attention as a synthetic tool for high-molecular-weight block copolymers and their micellar nano-objects. Up to recently, though, the use of thermoresponsive polymers as both macroRAFT agents and latex stabilizers was impossible in aqueous media due to their hydrophobicity at the usually high polymerization temperatures. In this work, we present a straightforward surfactant-free RAFT emulsion polymerization to obtain thermoresponsive styrenic block copolymers with molecular weights of around 100 kDa and their well-defined latexes. The stability of the aqueous latexes is achieved by adding 20 vol % of the cosolvent 1,4-dioxane (DOX), increasing the phase transition temperature (PTT) of the used thermoresponsive poly(N-acryloylpyrrolidine) (PAPy) macroRAFT agents above the polymerization temperature. Furthermore, this cosolvent approach is combined with the use of poly(N,N-dimethylacrylamide)-block-poly(N-acryloylpiperidine-co-N-acryloylpyrrolidine) (PDMA-b-P(APi-co-APy)) as the macroRAFT agent owning a short stabilizing PDMA end block and a widely adjustable PTT of the P(APi-co-APy) block in between 4 and 47 °C. The temperature-induced collapse of the latter under emulsion polymerization conditions leads to the formation of RAFT nanoreactors, which allows for a very fast chain growth of the polystyrene (PS) block. In dynamic light scattering (DLS), as well as cryo-transmission electron microscopy (cryoTEM), moreover, all created latexes indeed reveal a high (temperature) stability and a reversible collapse of the thermoresponsive coronal block upon heating. Hence, this paper pioneers a versatile way towards amphiphilic thermoresponsive high-molecular-weight block copolymers and their nano-objects with tailored corona switchability. Full article
(This article belongs to the Special Issue Emulsion Polymerization)
Show Figures

Graphical abstract

13 pages, 3483 KiB  
Article
Biosynthesis and Characterization of Recombinant Silk-Like Polypeptides Derived from the Heavy Chain of Silk Fibrion
by Yue Wu, Zhao Kang, Zhifang Tian, Mingyang Wu and Jiannan Wang *
National Engineering Laboratory for Modern Silk, College of Textile and Clothing Engineering, Soochow University, No. 199 Ren-ai Road, Suzhou Industrial Park, Suzhou 215123, Jiangsu Province, China
Polymers 2017, 9(12), 669; https://doi.org/10.3390/polym9120669 - 3 Dec 2017
Cited by 17 | Viewed by 6520
Abstract
In order to investigate the impacts on the structure and biomedical function of typical fragments derived from repetitive and non-repetitive regions of the Bombyx mori silk fibroin heavy chain, several block combination genes (gs16f1, gs16f4, gs16f8, and gs16f12) were designed, cloned [...] Read more.
In order to investigate the impacts on the structure and biomedical function of typical fragments derived from repetitive and non-repetitive regions of the Bombyx mori silk fibroin heavy chain, several block combination genes (gs16f1, gs16f4, gs16f8, and gs16f12) were designed, cloned into a fusion protein expression vector tagged with glutathione S-transferase (GST), and expressed in Escherichia coli. Fusion proteins GST-GS16F1, GST-GS16F4, and GST-GS16F8 were purified by GST affinity chromatography, and single bands were identified by SDS-PAGE. Under optimal initial cell density, in ducer concentration and induction expression time, the yield of purified GST-GS16F1, GST-GS16F4, and GST-GS16F8 per liter of bacterial culture reached 79, 53, and 28 mg, respectively. Mass spectrometry revealed molecular weights for GST-GS16F1, GST-GS16F4, and GST-GS16F8 of 37.7, 50.0, and 65.7 kDa, respectively, consistent with the theoretical values of 37.4, 49.4, and 65.5 kDa. Similarly, measured values of pI were 5.35, 4.5, and 4.2 for the fusion proteins, consistent with predicted values of 5.34, 4.44, and 4.09. CD spectra showed the molecular conformation of GS16F1 was mainly β-sheet structure, while more stable α-helix structure formed in GS16F4 and GS16F8. Full article
(This article belongs to the Special Issue Protein Biopolymer)
Show Figures

Graphical abstract

19 pages, 4826 KiB  
Article
Grafting of Hindered Phenol Groups onto Ethylene/α-Olefin Copolymer by Nitroxide Radical Coupling
by Serena Coiai 1, Francesca Cicogna 1,*, Chengcheng Yang 1, Veronika Tempesti 1, Sabrina Carola Carroccio 2,3, Giuliana Gorrasi 4, Raniero Mendichi 5, Nadka Tz. Dintcheva 6 and Elisa Passaglia 1
1 Istituto di Chimica dei Composti Organo Metallici (ICCOM), Consiglio Nazionale delle Ricerche, SS Pisa, Via G. Moruzzi 1, 56124 Pisa, Italy
2 Istituto per i Polimeri, Compositi e Biomateriali (IPCB), Consiglio Nazionale delle Ricerche, SS Catania, Via P. Gaifami 18, 95126 Catania, Italy
3 Istituto per la Microelettronica e Microsistemi (IMM), Consiglio Nazionale delle Ricerche, SS Catania (Università), Via S. Sofia 64, 95123 Catania, Italy
4 Dipartimento di Ingegneria Industriale, Università Degli Studi di Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano (SA), Italy
5 Istituto per lo Studio delle Macromolecule (ISMAC), Consiglio Nazionale delle Ricerche, Via A. Corti 12, 20133 Milano, Italy
6 Dipartimento di Ingegneria Civile, Ambientale, Aerospaziale, dei Materiali, Università di Palermo, Viale delle Scienze, Ed. 6, 90128 Palermo, Italy
Polymers 2017, 9(12), 670; https://doi.org/10.3390/polym9120670 - 4 Dec 2017
Cited by 15 | Viewed by 7070
Abstract
The covalent immobilization of hindered phenol groups, with potential antioxidant activity, onto an ethylene/α-olefin (EOC) copolymer was carried out by the nitroxide radical coupling (NRC) reaction performed in the melt with a peroxide and the 3,5-di-tert-butyl-4-hydroxybenzoyl-2,2,6,6-tetramethylpiperidine-1-oxyl radical (BHB-T). Functionalized EOC (EOC- [...] Read more.
The covalent immobilization of hindered phenol groups, with potential antioxidant activity, onto an ethylene/α-olefin (EOC) copolymer was carried out by the nitroxide radical coupling (NRC) reaction performed in the melt with a peroxide and the 3,5-di-tert-butyl-4-hydroxybenzoyl-2,2,6,6-tetramethylpiperidine-1-oxyl radical (BHB-T). Functionalized EOC (EOC-g-(BHB-T)) was exposed to photo- and thermo-oxidation. By comparison with some model compounds bearing the (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) moiety or the hindered phenol unit, it was observed that the grafted BHB-T could effectively help the stabilization of the polymer matrix both under photo- and thermo-oxidation. In addition, the immobilization of BHB-T can effectively increase the service life of the functionalized polymers when polymer films were put in contact with ethanol solution thus simulating a possible application of the modified polymer. Full article
Show Figures

Graphical abstract

17 pages, 3200 KiB  
Article
Effect of Superabsorbent Polymer on the Properties of Concrete
by Juntao Dang 1, Jun Zhao 2,* and Zhaohua Du 3
1 College of Civil Engineering, Zhengzhou University, Zhengzhou 450001, China
2 College of Mechanics and Engineering Science, Zhengzhou University, Zhengzhou 450001, China
3 Multi-Functional Design and Research Academy, Zhengzhou University, Zhengzhou 450052, China
Polymers 2017, 9(12), 672; https://doi.org/10.3390/polym9120672 - 4 Dec 2017
Cited by 108 | Viewed by 11918
Abstract
Incorporating superabsorbent polymer (SAP), which has the abilities of absorption and desorption in concrete can achieve the effect of internal curing. The influences of the volume, particle size and ways of entrained water of SAP on the workability, compressive strength, shrinkage, carbonation resistance [...] Read more.
Incorporating superabsorbent polymer (SAP), which has the abilities of absorption and desorption in concrete can achieve the effect of internal curing. The influences of the volume, particle size and ways of entrained water of SAP on the workability, compressive strength, shrinkage, carbonation resistance and chloride penetration resistance of concrete were analyzed through the macroscopic and microscopic test. The results show that pre-absorbed SAP can increase the slump of the mixture, but SAP without water absorption and pre-absorbed SAP with the deduction of internal curing water from mixing water can reduce the slump. The improvement effects of SAP on compressive strength of concrete increase gradually with the increase of age. Especially from 28 days, the compressive strength of concrete increases obviously. At later age, the compressive strengths of SAP concrete under natural curing environment exceed the strength of reference concrete under natural curing environment and nearly reach the strengths of reference concrete under standard curing environment. SAP effectively reduces the shrinkage of concrete, improves the concrete’s abilities of carbonation resistance and chloride penetration resistance. The microscopic test results show that SAP can effectively improve the micro structure and make the pore structure refined. When SAP is added into concrete, the gel pores and small capillary pores are increased, the size of big capillary pores and air pores are reduced. Full article
(This article belongs to the Special Issue Polymers for Modern and Advanced Engineering Applications)
Show Figures

Graphical abstract

12 pages, 5895 KiB  
Article
Elastic Shape Memory Hybrids Programmable at Around Body-Temperature for Comfort Fitting
by Tao Xi Wang 1, Chris Renata 1, Hong Mei Chen 2 and Wei Min Huang 1,*
1 School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
2 College of Chemistry and Materials Science, Sichuan Normal University, Chengdu 610066, China
Polymers 2017, 9(12), 674; https://doi.org/10.3390/polym9120674 - 4 Dec 2017
Cited by 19 | Viewed by 5011
Abstract
A series of silicone based elastic shape memory hybrids are fabricated. Their shape memory performance, mechanical behaviors at room temperature with/without programming and during fitting at 37 °C are investigated. It is found that these materials have good shape memory effect and are [...] Read more.
A series of silicone based elastic shape memory hybrids are fabricated. Their shape memory performance, mechanical behaviors at room temperature with/without programming and during fitting at 37 °C are investigated. It is found that these materials have good shape memory effect and are always highly elastic. At 37 °C, there are 10 min or more for fitting. Thus, it is concluded that this type of material has great potential as an elastic shape memory material for comfort fitting. Full article
(This article belongs to the Special Issue Shape Memory Polymers)
Show Figures

Graphical abstract

12 pages, 2593 KiB  
Article
Effects of Particle Size on the Morphology and Water- and Thermo-Resistance of Washed Cottonseed Meal-Based Wood Adhesives
by Zhongqi He 1,*, Huai N. Cheng 1, K. Thomas Klasson 1, O. Modesto Olanya 2 and Joseph Uknalis 2
1 Southern Regional Research Center, USDA-ARS, 1100 Robert E Lee Blvd., New Orleans, LA 70124, USA
2 Eastern Regional Research Center, USDA-ARS, 600 East Mermaid Lane, Wyndmoor, PA 19038, USA
Polymers 2017, 9(12), 675; https://doi.org/10.3390/polym9120675 - 5 Dec 2017
Cited by 8 | Viewed by 4307
Abstract
Water washing of cottonseed meal is more cost-efficient and environmentally friendly than protein isolation by means of alkaline extraction and acidic precipitation. Thus, water-washed cottonseed meal (WCSM) is more promising as biobased wood adhesives. In this work, we examined the effects of the [...] Read more.
Water washing of cottonseed meal is more cost-efficient and environmentally friendly than protein isolation by means of alkaline extraction and acidic precipitation. Thus, water-washed cottonseed meal (WCSM) is more promising as biobased wood adhesives. In this work, we examined the effects of the particle size on the morphology and adhesive performance of WCSM. Pilot-scale produced and dried WCSM was treated by three grinding methods: (1) ground by a hammer mill and passed through a 0.5-mm screen, (2) further ground by a cyclone mill and passed through a 0.5-mm screen, or (3) further ground by a ball mill and passed through a 0.18-mm screen. Micro-morphological examination revealed two types of particles. The filament-like particles were mainly fibrous materials from residual linters. Chunk-like particles were more like aggregates or accumulations of small particles, with proteins as the major component. Further grinding of the 0.5-mm Hammer product with the Cyclone and Ball mill led to more fine (smaller) particles in the WCSM products. The impact of further grinding on the dry and soaked adhesive strengths was minimal. However, the decrease of the hot and wet strengths of WCSM products by the additional grinding was significant (p ≤ 0.05). Data presented in this work is useful in developing the industrial standards of WCSM products used in wood bonding. Full article
Show Figures

Graphical abstract

11 pages, 2205 KiB  
Article
A Porous Cobalt (II) Metal–Organic Framework with Highly Efficient Electrocatalytic Activity for the Oxygen Evolution Reaction
by Qingguo Meng 1, Jianjian Yang 1, Shixuan Ma 1, Mujun Zhai 2 and Jitao Lu 1,*
1 College of Chemical Engineering and Environmental Chemistry, Weifang University, Weifang 261061, China
2 The Testing Center of Shandong Bureau of China Metallurgy and Geology Bureau, Jinan 250014, China
Polymers 2017, 9(12), 676; https://doi.org/10.3390/polym9120676 - 6 Dec 2017
Cited by 28 | Viewed by 6604
Abstract
A 3D porous framework ([Co1.5(tib)(dcpna)]·6H2O) (1) with a Wei topology has been synthesized by solvothermal reaction of 1,3,5-tris(1-imidazolyl)-benzene (tib), 5-(3′,5′-dicarboxylphenyl)nicotinic acid (H3dcpna) and cobalt nitrate. The electrocatalytic activity for water oxidation of 1 [...] Read more.
A 3D porous framework ([Co1.5(tib)(dcpna)]·6H2O) (1) with a Wei topology has been synthesized by solvothermal reaction of 1,3,5-tris(1-imidazolyl)-benzene (tib), 5-(3′,5′-dicarboxylphenyl)nicotinic acid (H3dcpna) and cobalt nitrate. The electrocatalytic activity for water oxidation of 1 has been investigated in alkaline solution. Compound 1 exhibits good oxygen evolution reaction (OER) activities in alkaline solution, exhibiting 10 mA·cm−2 at η = 360 mV with a Tafel slope of 89 mV·dec−1. The high OER activity can be ascribe to 1D open channels along b axis of 1, which expose more activity sites and facilitate the electrolyte penetration. Full article
(This article belongs to the Special Issue Coordination Polymer)
Show Figures

Graphical abstract

14 pages, 6964 KiB  
Article
The Preparations and Water Vapor Barrier Properties of Polyimide Films Containing Amide Moieties
by Kai Zhang, Qiaoxi Yu, Longji Zhu, Siwei Liu, Zhenguo Chi, Xudong Chen, Yi Zhang * and Jiarui Xu
PCFM Lab, GD HPPC Lab, Guangdong Engineering Technology Research Centre for High-performance Organic and Polymer Photoelectric Functional Films, State Key Laboratory of Optoelectronic Materials and Technologies, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, China
Polymers 2017, 9(12), 677; https://doi.org/10.3390/polym9120677 - 5 Dec 2017
Cited by 53 | Viewed by 15520
Abstract
Flexible displays are a systematic revolution in the field of display, in which high-performance and high-barrier polymer substrates are considered to be one of the most important key materials. In this work, high water vapor barrier polyimides containing amide moieties were synthesized via [...] Read more.
Flexible displays are a systematic revolution in the field of display, in which high-performance and high-barrier polymer substrates are considered to be one of the most important key materials. In this work, high water vapor barrier polyimides containing amide moieties were synthesized via the ternary polymerization of 4,4′-diaminobenzailide (DABA), 4,4′-diaminodipheny ether (ODA), and 3,3′,4,4′-biphenyl-tetracarboxylic acid dianhydride (BPDA) followed by thermal imidization. The relationship between the content of amide moieties and the water vapor barrier property of the prepared polyimides was studied by means of density test, water absorbing test, water contact angle test, water vapor permeation test, fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), thermogravimetry coupled with fourier transform infrared spectrometry (TG-FTIR), wide-angle X-ray diffraction analysis (WXRD), mechanical performance test, etc. The results show that the introduction of amide groups into polyimide (PI) main chains can improve the water vapor barrier properties of the polyimides effectively. The water vapor transmission rate (WVTR) of the polyimide films can be improved from 8.2365 g·(m2·24 h)−1 to 0.8670 g·(m2·24 h)−1 with the increasing content of amide moieties. Full article
(This article belongs to the Special Issue High Performance Polymers)
Show Figures

Graphical abstract

12 pages, 3159 KiB  
Article
Octane-Assisted Reverse Micellar Dyeing of Cotton with Reactive Dyes
by Alan Yiu-lun Tang 1, Cheng-hao Lee 2, Yanming Wang 1 and Chi-wai Kan 1,*
1 Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
2 Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
Polymers 2017, 9(12), 678; https://doi.org/10.3390/polym9120678 - 6 Dec 2017
Cited by 23 | Viewed by 5734
Abstract
In this study, we investigated the computer colour matching (CCM) of cotton fabrics dyed with reactive dye using the octane-assisted reverse micellar approach. The aim of this study is to evaluate the colour quality and compare the accuracy between CCM forecasting and simulated [...] Read more.
In this study, we investigated the computer colour matching (CCM) of cotton fabrics dyed with reactive dye using the octane-assisted reverse micellar approach. The aim of this study is to evaluate the colour quality and compare the accuracy between CCM forecasting and simulated dyeing produced by conventional water-based dyeing and octane-assisted reverse micellar dyeing. First, the calibration of dyeing databases for both dyeing methods was established. Standard samples were dyed with known dye concentrations. Computer colour matching was conducted by using the colour difference formula of International Commission on Illumination (CIE) L*a*b*. Experimental results revealed that the predicted concentrations were nearly the same as the expected known concentrations for both dyeing methods. This indicates that octane-assisted reverse micellar dyeing system can achieve colour matching as good as the conventional water-based dyeing system. In addition, when comparing the colour produced by the conventional water-based dyeing system and the octane-assisted reverse micellar dyeing system, the colour difference (ΔE) is ≤1, which indicates that the reverse micellar dyeing system could be applied for industrial dyeing with CCM. Full article
(This article belongs to the Special Issue Textile and Textile-Based Materials)
Show Figures

Graphical abstract

15 pages, 6540 KiB  
Article
Preparation of Fouling-Resistant Nanofibrous Composite Membranes for Separation of Oily Wastewater
by Fatma Yalcinkaya 1,*, Anna Siekierka 2 and Marek Bryjak 2
1 Department of Nanotechnology and Informatics, Technical University of Liberec, Institute for Nanomaterials, Advanced Technologies and Innovation, Studentska 1402/2, 46117 Liberec, Czech Republic
2 Faculty of Chemistry, Wroclaw University of Science and Technology, 27 Wybrzeze Stanislawa Wyspianskiego, 50-370 Wroclaw, Poland
Polymers 2017, 9(12), 679; https://doi.org/10.3390/polym9120679 - 6 Dec 2017
Cited by 33 | Viewed by 6703
Abstract
A facile and low-cost method has been developed for separation of oily wastewater. Polyvinylidene fluoride/polyacrylonitrile (PVDF/PAN) nanofibers laminated on a supporting layer were tested. In order to create highly permeable and fouling-resistant membranes, surface modifications of both fibers were conducted. The results of [...] Read more.
A facile and low-cost method has been developed for separation of oily wastewater. Polyvinylidene fluoride/polyacrylonitrile (PVDF/PAN) nanofibers laminated on a supporting layer were tested. In order to create highly permeable and fouling-resistant membranes, surface modifications of both fibers were conducted. The results of oily wastewater separation showed that, after low vacuum microwave plasma treatment with Argon (Ar) and chemical modification with sodium hydroxide (NaOH), the membranes had excellent hydrophilicity, due to the formation of active carboxylic groups. However, the membrane performance failed during the cleaning procedures. Titanium dioxide (TiO2) was grafted onto the surface of membranes to give them highly permeable and fouling-resistance properties. The results of the self-cleaning experiment indicated that grafting of TiO2 on the surface of the membranes after their pre-treatment with Ar plasma and NaOH increased the permeability and the anti-fouling properties. A new surface modification method using a combination of plasma and chemical treatment was introduced. Full article
(This article belongs to the Special Issue Electrospinning of Nanofibres)
Show Figures

Graphical abstract

8 pages, 1693 KiB  
Communication
Confinement Effects on Polymer Dynamics: Thermo-Responsive Behaviours of Hydroxypropyl Cellulose Polymers in Phospholipid-Coated Droplets (Water-in-Oil Emulsion)
by Kazunari Yoshida 1,*,†, Keitaro Horii 2,†, Azusa Saito 1, Akito Takashima 2 and Izumi Nishio 2
1 Department of Mechanical Systems Engineering, Graduate School of Science and Engineering, Yamagata University, 4-3-16, Jonan, Yonezawa 992-8510, Yamagata, Japan
2 Department of Physics and Mathematics, College of Science and Engineering, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara 252-5258, Kanagawa, Japan
These authors contributed equally to this work.
Polymers 2017, 9(12), 680; https://doi.org/10.3390/polym9120680 - 6 Dec 2017
Cited by 9 | Viewed by 5329
Abstract
In order to construct the artificial cells and to understand the physicochemical properties of living cells, it is important to clarify the cell-sized confinement effect on the behaviours of bio-inspired polymers. We report the dynamic behaviours of aqueous hydroxypropyl cellulose (HPC) solution coated [...] Read more.
In order to construct the artificial cells and to understand the physicochemical properties of living cells, it is important to clarify the cell-sized confinement effect on the behaviours of bio-inspired polymers. We report the dynamic behaviours of aqueous hydroxypropyl cellulose (HPC) solution coated with phospholipids in oil (water-in-oil droplets, W/O droplets), accompanied by an increase in the temperature. We directly observed the beginning of phase separation of HPC solution using a fluorescence microscope and confirmed the dependence of such phenomena on droplet size. The results indicate that the start time of phase separation is decreased with an increase in droplet size. The experimental results suggest that the confinement situation accelerates the phase separation of aqueous HPC solutions. Full article
(This article belongs to the Collection Polysaccharides)
Show Figures

Graphical abstract

14 pages, 6210 KiB  
Article
Carboxyl-Functionalized Polymeric Microspheres Prepared by One-Stage Photoinitiated RAFT Dispersion Polymerization
by Jianbo Tan 1,2,*, Xueliang Li 1,†, Jun He 1,†, Qin Xu 1, Yuxuan Zhang 1, Xiaocong Dai 1, Liangliang Yu 1, Ruiming Zeng 1 and Li Zhang 1,2,*
1 Department of Polymeric Materials and Engineering, School of Materials and Energy, Guangdong University of Technology, Guangzhou 510006, China
2 Guangdong Provincial Key Laboratory of Functional Soft Condensed Matter, Guangzhou 510006, China
These authors contributed equally to this work.
Polymers 2017, 9(12), 681; https://doi.org/10.3390/polym9120681 - 6 Dec 2017
Cited by 10 | Viewed by 7991
Abstract
Herein, we report a photoinitiated reversible addition-fragmentation chain transfer (RAFT) dispersion copolymerization of methyl methacrylate (MMA) and methyl methacrylic (MAA) for the preparation of highly monodisperse carboxyl-functionalized polymeric microspheres. High rates of polymerization were observed, with more than 90% particle yields being achieved [...] Read more.
Herein, we report a photoinitiated reversible addition-fragmentation chain transfer (RAFT) dispersion copolymerization of methyl methacrylate (MMA) and methyl methacrylic (MAA) for the preparation of highly monodisperse carboxyl-functionalized polymeric microspheres. High rates of polymerization were observed, with more than 90% particle yields being achieved within 3 h of UV irradiation. Effects of reaction parameters (e.g., MAA concentration, RAFT agent concentration, photoinitiator concentration, and solvent composition) were studied in detail, and highly monodisperse polymeric microspheres were obtained in most cases. Finally, silver (Ag) composite microspheres were prepared by in situ reduction of AgNO3 using the carboxyl-functionalized polymeric microspheres as the template. The obtained Ag composite microspheres were able to catalyze the reduction of methylene blue (MB) with NaBH4 as a reductant. Full article
(This article belongs to the Special Issue RAFT Living Radical Polymerization and Self-Assembly)
Show Figures

Graphical abstract

13 pages, 3876 KiB  
Article
Modification of Rule of Mixtures for Tensile Strength Estimation of Circular GFRP Rebars
by Young-Jun You 1,*, Jang-Ho Jay Kim 2, Ki-Tae Park 1, Dong-Woo Seo 1 and Tae-Hee Lee 2
1 Structural Engineering Research Institute, Korea Institute of Civil Engineering and Building Technology, 283 Goyangdae-Ro, Ilsanseo-Gu, Goyang-Si 10223, Korea
2 Concrete Structural Engineering Laboratory, School of Civil and Environmental Engineering, Yonsei University, 50 Yonsei-Ro, Seodaemun-Gu, Seoul 03722, Korea
Polymers 2017, 9(12), 682; https://doi.org/10.3390/polym9120682 - 7 Dec 2017
Cited by 28 | Viewed by 5548
Abstract
The rule of mixtures (ROM) method is often used to estimate the tensile strength of fiber reinforced polymers (FRPs) reinforcing bars (rebars). Generally, the ROM method predicts the FRP rebars’ modulus of elasticity adequately but overestimates their tensile strength. This may result from [...] Read more.
The rule of mixtures (ROM) method is often used to estimate the tensile strength of fiber reinforced polymers (FRPs) reinforcing bars (rebars). Generally, the ROM method predicts the FRP rebars’ modulus of elasticity adequately but overestimates their tensile strength. This may result from defects occurred during manufacture that prevent the used materials from exhibiting a sound performance and the shear-lag phenomenon by transmission of external forces through the surface of the rebar having a circular cross section. Due to the latter, there is a difference in fiber breaking points regarding the fibers located on the surface and fibers located at the center, and thus results in differences between the values calculated from the conventional ROM and the experimental result. In this study, for the purpose of resolving the problem, glass FRP (GFRP) rebars were shaped to have a hollow section at the center of their cross sections and were further subject to tensile strength tests. The test results were further placed under regression analysis and a modified ROM within ±5% accuracy compared to the experimental value was proposed for GFRP rebars with 13, 16, and 19 mm diameters. Full article
Show Figures

Figure 1

11 pages, 4812 KiB  
Article
Drag Reduction Using Polysaccharides in a Taylor–Couette Flow
by Pallavi Bhambri 1, Ravin Narain 2,* and Brian Fleck 1,*
1 Department of Mechanical Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AL T6G 1H9, Canada
2 Department of Chemical & Material Engineering, University of Alberta, 9211-116 Street NW, Edmonton, AL T6G 1H9, Canada
Polymers 2017, 9(12), 683; https://doi.org/10.3390/polym9120683 - 7 Dec 2017
Cited by 7 | Viewed by 5178
Abstract
Three different polysaccharides, aloe vera, Tamarind powder and pineapple fibers, are utilized as drag reducing agents in a turbulent flow. Using a Taylor–Couette setup, consisting of a rotating inner cylinder, for measuring the drag reduction, a range of Reynolds numbers from 4 × [...] Read more.
Three different polysaccharides, aloe vera, Tamarind powder and pineapple fibers, are utilized as drag reducing agents in a turbulent flow. Using a Taylor–Couette setup, consisting of a rotating inner cylinder, for measuring the drag reduction, a range of Reynolds numbers from 4 × 104 to 3 × 105 has been explored in this study. The results are in good agreement with previous studies on polysaccharides conducted in a pipe/channel flow and a maximum drag reduction of 35% has been observed. Further, novel additives such as cellulose nanocrystals (CNC), surfactants and CNC grafted with surfactants are also examined in this study for drag reduction. CNC due to its rigid rod structure reduced the drag by 30%. Surfactant, due to its unique micelle formation showed maximum drag reduction of 80% at low Re. Further, surfactant was grafted on CNC and was examined for drag reduction. However, drag reduction property of surfactant was observed to be significantly reduced after grafting on CNC. The effect of Reynolds number on drag reduction is studied for all the additives investigated in this study. Full article
(This article belongs to the Collection Polysaccharides)
Show Figures

Graphical abstract

12 pages, 3190 KiB  
Article
Impact Resistance Enhancement by Adding Core-Shell Particle to Epoxy Resin Modified with Hyperbranched Polymer
by Shuiping Li 1,2,*, Qisheng Wu 1,*, Huajun Zhu 1, Qing Lin 3 and Chengshuang Wang 1
1 School of Materials Science and Engineering, Yancheng Institute of Technology, Yancheng Jiangsu 224051, China
2 Institute of Cement Science and New Building Materials, China Building Materials Academy, Beijing 10024, China
3 School of Materials Engineering, Jinling Institute of Technology, Nanjing Jiangsu 211169, China
Polymers 2017, 9(12), 684; https://doi.org/10.3390/polym9120684 - 7 Dec 2017
Cited by 28 | Viewed by 6815
Abstract
A core-shell particle was fabricated by grafting amino-terminated hyperbranched polymer to the surface of silica nanoparticles. The influences of core-shell particle contents on the tensile and impact strength of the epoxy thermosets modified with amino-terminated hyperbranched polymer were discussed in detail. For comparison, [...] Read more.
A core-shell particle was fabricated by grafting amino-terminated hyperbranched polymer to the surface of silica nanoparticles. The influences of core-shell particle contents on the tensile and impact strength of the epoxy thermosets modified with amino-terminated hyperbranched polymer were discussed in detail. For comparison, core-shell particle was added into the epoxy/polyamide system for toughness improvement. Results from tensile and impact tests are provided. The introduction of core-shell particle into the epoxy/polyamide systems just slightly enhanced the tensile and impact strength. The incorporation of 3 wt % core-shell particle could substantially improve the tensile and impact strength of epoxy/amino-terminated hyperbranched polymer thermosets. Field emission-scanning electron microscope images of the impact fracture surfaces showed that the excellent impact resistance of epoxy/amino-terminated hyperbranched polymer/core-shell particle thermosets may be attributed to the synergistic effect of shearing deformation and crack pinning/propagation, which is induced by the good compatibility between epoxy matrix and core-shell particle in the presence of amino-terminated hyperbranched polymer. Full article
(This article belongs to the Collection Polymeric Adhesives)
Show Figures

Graphical abstract

12 pages, 3011 KiB  
Article
Construction of Supramolecular Nanostructures from V-Shaped Amphiphilic Rod-Coil Molecules Incorporating Phenazine Units
by Junying Xu 1,†, Shengsheng Yu 1,†, Keli Zhong 2,* and Long Yi Jin 1,*
1 Key Laboratory for Organism Resources of the Changbai Mountain and Functional Molecules, Department of Chemistry, College of Science, Yanbian University, Yanji133002, China
2 College of Chemistry, Chemical Engineering and Food Safety, Bohai University, Jinzhou 121013, China
These authors contributed equally to this work.
Polymers 2017, 9(12), 685; https://doi.org/10.3390/polym9120685 - 7 Dec 2017
Cited by 7 | Viewed by 4565
Abstract
A series of bent-shaped molecules, consisting of dibenzo[a,c]phenazine and phenyl groups connected together as a rod segment, and poly(ethylene oxide) (PEO) with a degree of polymerization (DP) of 6 as the coil segment, were synthesized. The self-assembling behavior of these molecules [...] Read more.
A series of bent-shaped molecules, consisting of dibenzo[a,c]phenazine and phenyl groups connected together as a rod segment, and poly(ethylene oxide) (PEO) with a degree of polymerization (DP) of 6 as the coil segment, were synthesized. The self-assembling behavior of these molecules by differential scanning calorimetry (DSC), thermal optical polarized microscopy (POM), small-angle X-ray scattering spectroscopy (SAXS), atomic force microscopy (AFM), and transmission electron microscopy (TEM), revealed that carboxyl or butoxy carbonyl groups at the 11 position of dibenzo[a,c]phenazine noticeably influence self-organization of molecules into supramolecular aggregates in bulk and aqueous solutions. Molecules 1 and 2 with chiral or non-chiral PEO coil chains and the carboxyl group at the rod segments self-organize into a hexagonal perforated lamellar structure and a hexagonal columnar structure in the solid state. In aqueous solution, molecules 1 and 2 self-assemble into diverse lengths of nanofibers, whereas molecules 3 and 4 with butoxy carbonyl groups exhibit a self-organizing capacity to form diverse sizes of spherical aggregates. Full article
Show Figures

Graphical abstract

14 pages, 1980 KiB  
Article
On the Limits of Benzophenone as Cross-Linker for Surface-Attached Polymer Hydrogels
by Esther K. Riga, Julia S. Saar, Roman Erath, Michelle Hechenbichler and Karen Lienkamp *
1 Freiburg Center für Interactive Materials and Bioinspired Technologies (FIT) and Department of Microsystems Engineering (IMTEK), Albert-Ludwigs-Universität, Georges-Köhler-Allee 105, 79110 Freiburg, Germany
These authors contributed equally to this work.
Polymers 2017, 9(12), 686; https://doi.org/10.3390/polym9120686 - 7 Dec 2017
Cited by 36 | Viewed by 10105
Abstract
The synthesis of different photo-reactive poly(alkenyl norbornenes) and poly(oxonorbornenes) containing benzophenone (BP) via ring-opening metatheses polymerization (ROMP) is described. These polymers are UV irradiated to form well-defined surface-attached polymer networks and hydrogels. The relative propensity of the polymers to cross-link is evaluated by [...] Read more.
The synthesis of different photo-reactive poly(alkenyl norbornenes) and poly(oxonorbornenes) containing benzophenone (BP) via ring-opening metatheses polymerization (ROMP) is described. These polymers are UV irradiated to form well-defined surface-attached polymer networks and hydrogels. The relative propensity of the polymers to cross-link is evaluated by studying their gel content and its dependency on BP content, irradiation wavelength (254 or 365 nm) and energy dose applied (up to 11 J·cm2). Analysis of the UV spectra of the polymer networks demonstrates that the poly(oxonorbornenes) show the expected BP-induced crosslinking behavior at 365 nm, although high irradiation energy doses and BP content are needed. However, these polymers undergo chain scission at 254 nm. The poly(alkenyl norbornenes), on the other hand, do not cross-link at 365 nm, whereas moderate to good cross-linking is observed at 254 nm. UV spectra demonstrate that the cross-linking at 254 nm is due to BP cross-linking combined with a [2 + 2] cylcoaddition of the alkenyl double bonds. This indicates limitations of benzophenone as a universally applicable cross-linking for polymer networks and hydrogels. Full article
(This article belongs to the Special Issue Microgels and Hydrogels at Interfaces)
Show Figures

Graphical abstract

23 pages, 6314 KiB  
Article
Biocompatibility Assessment of Conducting PANI/Chitosan Nanofibers for Wound Healing Applications
by Panagiota Moutsatsou, Karen Coopman and Stella Georgiadou *
Department of Chemical Engineering, Loughborough University, Loughborough LE11 3TU, Leicestershire, UK
Polymers 2017, 9(12), 687; https://doi.org/10.3390/polym9120687 - 8 Dec 2017
Cited by 71 | Viewed by 7754
Abstract
As electroactive polymers have recently presented potential in applications in the tissue engineering and biomedical field, this study is aiming at the fabrication of composite nanofibrous membranes containing conducting polyaniline and at the evaluation of their biocompatibility. For that purpose, conducting polyaniline–chitosan (PANI/CS) [...] Read more.
As electroactive polymers have recently presented potential in applications in the tissue engineering and biomedical field, this study is aiming at the fabrication of composite nanofibrous membranes containing conducting polyaniline and at the evaluation of their biocompatibility. For that purpose, conducting polyaniline–chitosan (PANI/CS) defect free nanofibres of different ratios (1:3; 3:5 and 1:1) were produced with the electrospinning method. They were characterized as for their morphology, hydrophilicity and electrical conductivity. The membranes were then evaluated for their cellular biocompatibility in terms of cell attachment, morphology and cell proliferation. The effect of the PANI content on the membrane properties is discussed. Increase in PANI content resulted in membranes with higher hydrophobicity and higher electrical conductivity. It was found that none of the membranes showed any toxic effects on osteoblasts and fibroblasts, and that they all supported cell attachment and growth, even to a greater extent than tissue culture plastic. The membrane with the PANI/CS ratio 1:3 supports better cell attachment and proliferation for both cell lines due to a synergistic effect of hydrophilicity retention due to the high chitosan content and the conductivity that PANI introduced to the membrane. Full article
(This article belongs to the Collection Polysaccharides)
Show Figures

Graphical abstract

12 pages, 4129 KiB  
Article
Thermal Transport in Soft PAAm Hydrogels
by Ni Tang 1,†, Zhan Peng 2,3,†, Rulei Guo 2,3,†, Meng An 2,3, Xiandong Chen 2,3, Xiaobo Li 2,3, Nuo Yang 2,3,* and Jianfeng Zang 1,4,*
1 School of Optical and Electronic Information, Huazhong University of Science and Technology, 1037 Luoyu Rd., Wuhan 430074, China
2 Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, 1037 Luoyu Rd., Wuhan 430074, China
3 Nano Interface Center for Energy, School of Energy and Power Engineering, Huazhong University of Science and Technology, 1037 Luoyu Rd., Wuhan 430074, China
4 Innovation Institute, Huazhong University of Science and Technology, 1037 Luoyu Rd., Wuhan 430074, China
These authors contributed equally to this work.
Polymers 2017, 9(12), 688; https://doi.org/10.3390/polym9120688 - 8 Dec 2017
Cited by 95 | Viewed by 14998
Abstract
As the interface between human and machine becomes blurred, hydrogel incorporated electronics and devices have emerged to be a new class of flexible/stretchable electronic and ionic devices due to their extraordinary properties, such as softness, mechanically robustness, and biocompatibility. However, heat dissipation in [...] Read more.
As the interface between human and machine becomes blurred, hydrogel incorporated electronics and devices have emerged to be a new class of flexible/stretchable electronic and ionic devices due to their extraordinary properties, such as softness, mechanically robustness, and biocompatibility. However, heat dissipation in these devices could be a critical issue and remains unexplored. Here, we report the experimental measurements and equilibrium molecular dynamics simulations of thermal conduction in polyacrylamide (PAAm) hydrogels. The thermal conductivity of PAAm hydrogels can be modulated by both the effective crosslinking density and water content in hydrogels. The effective crosslinking density dependent thermal conductivity in hydrogels varies from 0.33 to 0.51 Wm−1K−1, giving a 54% enhancement. We attribute the crosslinking effect to the competition between the increased conduction pathways and the enhanced phonon scattering effect. Moreover, water content can act as filler in polymers which leads to nearly 40% enhancement in thermal conductivity in PAAm hydrogels with water content vary from 23 to 88 wt %. Furthermore, we find the thermal conductivity of PAAm hydrogel is insensitive to temperature in the range of 25–40 °C. Our study offers fundamental understanding of thermal transport in soft materials and provides design guidance for hydrogel-based devices. Full article
(This article belongs to the Special Issue Soft Materials and Systems)
Show Figures

Graphical abstract

17 pages, 5282 KiB  
Article
Plateau-Shaped Flexible Polymer Microelectrode Array for Neural Recording
by Jun-Min Kim 1,*, Changkyun Im 2 and Woo Ram Lee 1
1 Medical Device Research Center Medical & Health Device Division, Korea Testing Laboratory, Seoul 52852, Korea
2 Dental Research Institute, Seoul National University School of Dentistry, Seoul 03080, Korea
Polymers 2017, 9(12), 690; https://doi.org/10.3390/polym9120690 - 8 Dec 2017
Cited by 23 | Viewed by 8410
Abstract
Conventional polymer multielectrode arrays (MEAs) have limitations resulting from a high Young’s modulus, including low conformability and gaps between the electrodes and neurons. These gaps are not a problem in soft tissues such as the brain, due to the repopulation phenomenon. However, gaps [...] Read more.
Conventional polymer multielectrode arrays (MEAs) have limitations resulting from a high Young’s modulus, including low conformability and gaps between the electrodes and neurons. These gaps are not a problem in soft tissues such as the brain, due to the repopulation phenomenon. However, gaps can result in signal degradation when recording from a fiber bundle, such as the spinal cord. Methods: We propose a method for fabricating flexible polydimethylsiloxane (PDMS)-based MEAs featuring plateau-shaped microelectrodes. The proposed fabrication technique enables the electrodes on the surface of MEAs to make a tight connection to the neurons, because the wire of the MEA is fabricated to be plateau-shaped, as the Young’s modulus of PDMS is similar to soft tissues and PDMS follows the curvature of the neural tissue due to its high conformability compared to the other polymers. Injury caused by the movement of the MEAs can therefore be minimized. Each electrode has a diameter of 130 μm and the 8-channel array has a center-to-center electrode spacing of 300 μm. The signal-to-noise ratio of the plateau-shaped electrodes was larger than that of recessed electrodes because there was no space between the electrode and neural cell. Reliable neural recordings were possible by adjusting the position of the electrode during the experiment without trapping air under the electrodes. Simultaneous multi-channel neural recordings were successfully achieved from the spinal cord of rodents. We describe the fabrication technique, electrode 3D profile, electrode impedance, and MEA performance in in vivo experiments in rodents. Full article
(This article belongs to the Special Issue Siloxane-Based Polymers)
Show Figures

Graphical abstract

20 pages, 7299 KiB  
Article
Metal and Ligand Effects on the Construction of Divalent Coordination Polymers Based on bis-Pyridyl-bis-amide and Polycarboxylate Ligands
by Miao-Ning Chang, Xiang-Kai Yang, Pradhumna Mahat Chhetri and Jhy-Der Chen *
Department of Chemistry, Chung-Yuan Christian University, Chung-Li 32023, Taiwan
Polymers 2017, 9(12), 691; https://doi.org/10.3390/polym9120691 - 8 Dec 2017
Cited by 20 | Viewed by 5623
Abstract
Ten coordination polymers constructed from divalent metal salts, polycarboxylic acids, and bis-pyridyl-bis-amide ligands with different donor atom positions and flexibility are reported. They were structurally characterized by single-crystal X-ray diffraction. The ten coordination polymers are as follows: (1) {[Ni(L1 [...] Read more.
Ten coordination polymers constructed from divalent metal salts, polycarboxylic acids, and bis-pyridyl-bis-amide ligands with different donor atom positions and flexibility are reported. They were structurally characterized by single-crystal X-ray diffraction. The ten coordination polymers are as follows: (1) {[Ni(L1)(3,5-PDA)(H2O)3]·2H2O}n (L1 = N,N′-di(3-pyridyl)suberoamide, 3,5-H2PDA = 3,5-pyridinedicarboxylic acid); (2) {[Ni2(L1)2(1,3,5-HBTC)2(H2O)4]·H2O}n (1,3,5-H3BTC = 1,3,5-benzenetricarboxylic acid); (3) {[Ni(L2)(5-tert-IPA)(H2O)2]·2H2O}n (L2 = N,N′-di(3-pyridyl)adipoamide, 5-tert-H2IPA = 5-tert-butylisophthalic acid); (4) [Ni(L3)1.5(5-tert-IPA)]n (L3 = N,N′-di(4-pyridyl)adipoamide); (5) [Co(L1)(1,3,5-HBTC)(H2O)]n; (6) {[Co3(L1)3(1,3,5-BTC)2(H2O)2]·6H2O}n; (7) [Cu(L4)(AIPA)]n (L4 = N,N′-bis(3-pyridinyl)terephthalamide, H2AIPA = 5-acetamido isophthalic acid); (8) {[Cu(L2)0.5(AIPA)]·MeOH}n; (9) {[Zn(L4)(AIPA)]·2H2O}n; and (10) {[Zn(L2)(AIPA)]·2H2O}n. Complex 1 forms a 1D chain and 2 is a two-fold interpenetrated 2D layer with the sql topology, while 3 is a 2D layer with the hcp topology and 4 shows a self-catenated 3D framework with the rare (42·67·8)-hxg-d-5-C2/c topology. Different Co/1,3,5-H3BTC ratios were used to prepare 5 and 6, affording a 2D layer with the sql topology and a 2D layer with the (4·85)2(4)2(83)2(8) topology that can be further simplified to an hcp topology. While complex 7 is a 2D layer with the (42·67·8)(42·6)-3,5L2 topology and 8 is a 2-fold interpenetrated 3D framework with the pcu topology, complexes 9 and 10 are self-catenated 3D frameworks with the (424·64)-8T2 and the (44·610·8)-mab topologies, respectively. The effects of the identity of the metal center, the ligand isomerism, and the flexibility of the spacer ligands on the structural diversity of these divalent coordination polymers are discussed. The luminescent properties of 9 and 10 and their photocatalytic effects on the degradation of dyes are also investigated. Full article
(This article belongs to the Special Issue Coordination Polymer)
Show Figures

Graphical abstract

30 pages, 6554 KiB  
Article
Non-Fullerene Acceptor-Based Solar Cells: From Structural Design to Interface Charge Separation and Charge Transport
by Qungui Wang 1, Yuanzuo Li 1,*, Peng Song 2, Runzhou Su 1, Fengcai Ma 2 and Yanhui Yang 3,*
1 College of Science, Northeast Forestry University, Harbin 150040, China
2 Department of Physics, Liaoning University, Shenyang 110036, China
3 School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 639798, Singapore
Polymers 2017, 9(12), 692; https://doi.org/10.3390/polym9120692 - 8 Dec 2017
Cited by 31 | Viewed by 8299
Abstract
The development of non-fullerene small molecule as electron acceptors is critical for overcoming the shortcomings of fullerene and its derivatives (such as limited absorption of light, poor morphological stability and high cost). We investigated the electronic and optical properties of the two selected [...] Read more.
The development of non-fullerene small molecule as electron acceptors is critical for overcoming the shortcomings of fullerene and its derivatives (such as limited absorption of light, poor morphological stability and high cost). We investigated the electronic and optical properties of the two selected promising non-fullerene acceptors (NFAs), IDIC and IDTBR, and five conjugated donor polymers using quantum-chemical method (QM). Based on the optimized structures of the studied NFAs and the polymers, the ten donor/acceptor (D/A) interfaces were constructed and investigated using QM and Marcus semi-classical model. Firstly, for the two NFAs, IDTBR displays better electron transport capability, better optical absorption ability, and much greater electron mobility than IDIC. Secondly, the configurations of D/A yield the more bathochromic-shifted and broader sunlight absorption spectra than the single moiety. Surprisingly, although IDTBR has better optical properties than IDIC, the IDIC-based interfaces possess better electron injection abilities, optical absorption properties, smaller exciton binding energies and more effective electronic separation than the IDTBR-based interfaces. Finally, all the polymer/IDIC interfaces exhibit large charge separation rate (KCS) (up to 1012–1014 s−1) and low charge recombination rate (KCR) (<106 s−1), which are more likely to result in high power conversion efficiencies (PCEs). From above analysis, it was found that the polymer/IDIC interfaces should display better performance in the utility of bulk-heterojunction solar cells (BHJ OSC) than polymer/IDTBR interfaces. Full article
(This article belongs to the Special Issue Polymer Solar Cells)
Show Figures

Graphical abstract

11 pages, 3613 KiB  
Article
Catalyst Influence on Undesired Side Reactions in the Polycondensation of Fully Bio-Based Polyester Itaconates
by Ina Schoon, Marcel Kluge, Steven Eschig and Tobias Robert *
Fraunhofer Institute for Wood Research–Wilhelm-Klauditz-Institut WKI, Bienroder Weg 54E, 38108 Braunschweig, Germany
Polymers 2017, 9(12), 693; https://doi.org/10.3390/polym9120693 - 9 Dec 2017
Cited by 27 | Viewed by 9254
Abstract
Bio-based unsaturated polyester resins derived from itaconic acid can be an alternative to established resins of this type in the field of radical-curing resins. However, one of the challenges of these polyester itaconates is the somewhat more elaborate synthetic process, especially under polycondensation [...] Read more.
Bio-based unsaturated polyester resins derived from itaconic acid can be an alternative to established resins of this type in the field of radical-curing resins. However, one of the challenges of these polyester itaconates is the somewhat more elaborate synthetic process, especially under polycondensation conditions used on an industrial scale. The α,β-unsaturated double bond of the itaconic acid is prone to side reactions that can lead to the gelation of the polyester resin under standard conditions. This is especially true when bio-based diols such as 1,3-propanediol or 1,4-butanediol are used to obtain resins that are 100% derived from renewable resources. It was observed in earlier studies that high amounts of these aliphatic diols in the polyester lead to low conversion and gelation of the resins. In this work, a catalytic study using different diols was performed in order to elucidate the reasons for this behavior. It was shown that the choice of catalyst has a crucial influence on the side reactions occurring during the polycondensation reactions. In addition, the side reactions taking place were identified and suppressed. These results will allow for the synthesis of polyester itaconates on a larger scale, setting the stage for their industrial application. Full article
(This article belongs to the Special Issue Biodegradable and Biobased Polyesters)
Show Figures

Graphical abstract

15 pages, 6341 KiB  
Article
Preparation and Properties of Novel Thermoplastic Vulcanizate Based on Bio-Based Polyester/Polylactic Acid, and Its Application in 3D Printing
by Yu Gao 1,2, Yan Li 1,2, Xiaoran Hu 1,2, Weidong Wu 1,2, Zhao Wang 1,2, Runguo Wang 1,3,* and Liqun Zhang 1,3,*
1 Key Laboratory of Beijing City for Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029, China
2 State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China
3 Beijing Laboratory of Biomedical Materials, Beijing University of Chemical Technology, Beijing 100029, China
Polymers 2017, 9(12), 694; https://doi.org/10.3390/polym9120694 - 9 Dec 2017
Cited by 36 | Viewed by 8897
Abstract
Thermoplastic vulcanizate (TPV) combines the high elasticity of elastomers and excellent processability of thermoplastics. Novel bio-based TPV based on poly (lactide) (PLA) and poly (1,4-butanediol/2,3-butanediol/succinate/itaconic acid) (PBBSI) were prepared in this research. PBBSI copolyesters were synthesized by melting polycondensation, and the molecular weights, [...] Read more.
Thermoplastic vulcanizate (TPV) combines the high elasticity of elastomers and excellent processability of thermoplastics. Novel bio-based TPV based on poly (lactide) (PLA) and poly (1,4-butanediol/2,3-butanediol/succinate/itaconic acid) (PBBSI) were prepared in this research. PBBSI copolyesters were synthesized by melting polycondensation, and the molecular weights, chemical structures and compositions of the copolyesters were characterized by GPC, NMR and FTIR. Bio-based 2,3-butanediol was successfully incorporated to depress the crystallization behavior of the PBBSI copolyester. With an increase of 2,3-butanediol content, the PBBSI copolyester transformed from a rigid plastic to a soft elastomer. Furthermore, the obtained TPV has good elasticity and rheological properties, which means it can be applied as a 3D-printing material. Full article
(This article belongs to the Special Issue Biodegradable and Biobased Polyesters)
Show Figures

Graphical abstract

14 pages, 2219 KiB  
Article
Effects of Acid and Salt Solutions on the Pasting, Rheology and Texture of Lotus Root Starch–Konjac Glucomannan Mixture
by Fusheng Zhang 1, Min Liu 1, Fang Mo 1, Meixia Zhang 2 and Jiong Zheng 1,*
1 College of Food Science, Southwest University, Chongqing 400715, China
2 School of Forestry and Life Science, Chongqing University of Arts and Sciences, Chongqing 402160, China
Polymers 2017, 9(12), 695; https://doi.org/10.3390/polym9120695 - 10 Dec 2017
Cited by 26 | Viewed by 7681
Abstract
To explore the functional properties of mixed biopolymer systems affected by acid and salts. The effects of acid and salt solutions (i.e., NaCl, KCl and CaCl2) on the pasting, rheology, texture and microstructure of lotus root starch–konjac glucomannan (LRS/KGM) mixtures were [...] Read more.
To explore the functional properties of mixed biopolymer systems affected by acid and salts. The effects of acid and salt solutions (i.e., NaCl, KCl and CaCl2) on the pasting, rheology, texture and microstructure of lotus root starch–konjac glucomannan (LRS/KGM) mixtures were assessed. Acid (citric acid buffer) treatment worsened the pasting (except for breakdown viscosity), rheological (except for fluid index), and textural properties, thereby inhibiting retrogradation, weakening pseudoplasticity and thickening, and reducing mixture viscoelasticity. Furthermore, it led to destructive ruptures and large pores in the internal microstructure. Salt treatment worsened the pasting properties (except for setback viscosity), thus inhibiting retrogradation and weakening pseudoplasticity, but enhanced the rheological properties, improving thickening and fluctuating viscoelasticity of the mixture. Moreover, salt addition decreased the hardness while increasing mixture cohesiveness, and modified the elasticity, adhesiveness and internal microstructure in a salt type- and concentration-dependent manner. A salt solution concentration of 0.5 mol/L NaCl, 0.1 mol/L KCl, and 0.5 mol/L CaCl2 led to the mixture with the best texture and gel network. Full article
(This article belongs to the Collection Polysaccharides)
Show Figures

Graphical abstract

18 pages, 14478 KiB  
Article
Experimental Investigation of the Magnetorheological Behavior of PDMS Elastomer Reinforced with Iron Micro/Nanoparticles
by Luis Manuel Palacios-Pineda 1,2, Imperio Anel Perales-Martinez 1,*, Luis M. Lozano-Sanchez 1, Oscar Martínez-Romero 1, Jesús Puente-Córdova 3, Emmanuel Segura-Cárdenas 1 and Alex Elías-Zúñiga 1
1 Tecnologico de Monterrey, Escuela de Ingeniería y Ciencias, Ave. Eugenio Garza Sada 2501, Monterrey 64849, Mexico
2 División de Estudios de Posgrado e Investigación, Tecnológico Nacional de Mexico, Instituto Tecnológico de Pachuca, Carr. México-Pachuca km 87.5, Col. Venta Prieta, C.P., Pachuca 42080, Mexico
3 Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Av. Universidad s/n, Ciudad Universitaria, C.P., San Nicolas de los Garza 66451, Mexico
Polymers 2017, 9(12), 696; https://doi.org/10.3390/polym9120696 - 10 Dec 2017
Cited by 36 | Viewed by 6872
Abstract
The aim of this article focuses on identifying how the addition of iron micro- and nanoparticles influences the physical properties of magnetorheological composite materials developed with a polydimethylsiloxane (PDMS) matrix with different contents of silicone oil used as additive. A number of characterization [...] Read more.
The aim of this article focuses on identifying how the addition of iron micro- and nanoparticles influences the physical properties of magnetorheological composite materials developed with a polydimethylsiloxane (PDMS) matrix with different contents of silicone oil used as additive. A number of characterization techniques have been performed in order to fully characterize the samples, such as cyclic and uniaxial extension, rheology, swelling, Vibrating sample magnetometer (VSM), X-ray Diffraction (XRD), Scanning electron microscopy (SEM), Fourier-Transform Infrared (FTIR), X-ray photoelectronic spectroscopy (XPS) and Thermogravimetric analysis (TGA). The comparison between two matrices with different shore hardnesses and their mechanical and chemical properties are elucidated by swelling and tensile tests. In fact, swelling tests showed that higher crosslink density leads to increasing elongation at break and tensile strength values for the composite materials. The best mechanical performance in the magnetorheological material was observed for those samples manufactured using a higher silicone oil content in a hard polymeric matrix. Furthermore, it has been found that the magnetic properties are enhanced when nanoparticles are used as fillers instead of microparticles. Full article
(This article belongs to the Special Issue Elastomers)
Show Figures

Graphical abstract

19 pages, 4699 KiB  
Article
Hydroxypropyltrimethyl Ammonium Chloride Chitosan Functionalized-PLGA Electrospun Fibrous Membranes as Antibacterial Wound Dressing: In Vitro and In Vivo Evaluation
by Shengbing Yang 1, Xiuguo Han 1, Yuhang Jia 2, Hongbo Zhang 2,* and Tingting Tang 1,*
1 Shanghai Key Laboratory of Orthopaedic Implants, Department of Orthopaedic Surgery, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China
2 School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, China
Polymers 2017, 9(12), 697; https://doi.org/10.3390/polym9120697 - 11 Dec 2017
Cited by 42 | Viewed by 9395
Abstract
A novel poly(lactic-co-glycolic acid) (PLGA)-hydroxypropyltrimethyl ammonium chloride chitosan (HACC) composite nanofiber wound dressing was prepared through electrospinning and the entrapment-graft technique as an antibacterial dressing for cutaneous wound healing. HACC with 30% degrees of substitution (DS) was immobilized onto the surface [...] Read more.
A novel poly(lactic-co-glycolic acid) (PLGA)-hydroxypropyltrimethyl ammonium chloride chitosan (HACC) composite nanofiber wound dressing was prepared through electrospinning and the entrapment-graft technique as an antibacterial dressing for cutaneous wound healing. HACC with 30% degrees of substitution (DS) was immobilized onto the surface of PLGA membranes via the reaction between carboxyl groups in PLGA after alkali treatment and the reactive groups (–NH2) in HACC molecules. The naked PLGA and chitosan graft PLGA (PLGA-CS) membranes served as controls. The surface immobilization was characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared (FTIR), thermogravimetric analysis (TGA) and energy dispersive X-ray spectrometry (EDX). The morphology studies showed that the membranes remain uniform after the immobilization process. The effects of the surface modification by HACC and CS on the biological properties of the membranes were also investigated. Compared with PLGA and PLGA-CS, PLGA-HACC exhibited more effective antibacterial activity towards both Gram-positive (S. aureus) and Gram-negative (P. aeruginosa) bacteria. The newly developed fibrous membranes were evaluated in vitro for their cytotoxicity using human dermal fibroblasts (HDFs) and human keratinocytes (HaCaTs) and in vivo using a wound healing mice model. It was revealed that PLGA-HACC fibrous membranes exhibited favorable cytocompatibility and significantly stimulated adhesion, spreading and proliferation of HDFs and HaCaTs. PLGA-HACC exhibited excellent wound healing efficacy, which was confirmed using a full thickness excision wound model in S. aureus-infected mice. The experimental results in this work suggest that PLGA-HACC is a strong candidate for use as a therapeutic biomaterial in the treatment of infected wounds. Full article
(This article belongs to the Collection Polysaccharides)
Show Figures

Graphical abstract

13 pages, 6004 KiB  
Article
Acetal-Linked Paclitaxel Polymeric Prodrug Based on Functionalized mPEG-PCL Diblock Polymer for pH-Triggered Drug Delivery
by Yinglei Zhai 1,2,†, Xing Zhou 3,†, Lina Jia 4, Chao Ma 5, Ronghua Song 1, Yanhao Deng 1, Xueyao Hu 1 and Wei Sun 1,*
1 Department of Biomedical Engineering, School of Medical Devices, Shenyang Pharmaceutical University, Shenyang 110016, China
2 State Key Laboratory for Marine Corrosion and Protection, Luoyang Ship Material Research Institute (LSMRI), Qingdao 266101, China
3 Hainan Institute of Materia Medica, Haikou 570311, China
4 Department of Pharmacology, School of Life Science and Biopharmaceutics, Shenyang Pharmaceutical University, Shenyang 110016, China
5 College of Food & Pharmaceutical Engineering, Guizhou Institute of Technology, Guizhou 550003, China
These two authors contributed equally to this work
Polymers 2017, 9(12), 698; https://doi.org/10.3390/polym9120698 - 11 Dec 2017
Cited by 29 | Viewed by 7700
Abstract
The differences in micro-environment between cancer cells and the normal ones offer the possibility to develop stimuli-responsive drug-delivery systems for overcoming the drawbacks in the clinical use of anticancer drugs, such as paclitaxel, doxorubicin, and etc. Hence, we developed a novel endosomal pH-sensitive [...] Read more.
The differences in micro-environment between cancer cells and the normal ones offer the possibility to develop stimuli-responsive drug-delivery systems for overcoming the drawbacks in the clinical use of anticancer drugs, such as paclitaxel, doxorubicin, and etc. Hence, we developed a novel endosomal pH-sensitive paclitaxel (PTX) prodrug micelles based on functionalized poly(ethylene glycol)-poly(ε-caprolactone) (mPEG-PCL) diblock polymer with an acid-cleavable acetal (Ace) linkage (mPEG-PCL-Ace-PTX). The mPEG-PCL-Ace-PTX5 with a high drug content of 23.5 wt % was self-assembled in phosphate buffer (pH 7.4, 10 mM) into nanosized micelles with an average diameter of 68.5 nm. The in vitro release studies demonstrated that mPEG-PCL-Ace-PTX5 micelles was highly pH-sensitive, in which 16.8%, 32.8%, and 48.2% of parent free PTX was released from mPEG-PCL-Ace-PTX5 micelles in 48 h at pH 7.4, 6.0, and 5.0, respectively. Thiazolyl Blue Tetrazolium Bromide (MTT) assays suggested that the pH-sensitive PTX prodrug micelles displayed higher therapeutic efficacy against MCF-7 cells compared with free PTX. Therefore, the PTX prodrug micelles with acetal bond may offer a promising strategy for cancer therapy. Full article
(This article belongs to the Special Issue Polymer Micelles)
Show Figures

Graphical abstract

16 pages, 4692 KiB  
Article
Macro-Micro Simulation for Polymer Crystallization in Couette Flow
by Chunlei Ruan 1,*, Kunfeng Liang 2 and Enli Liu 1
1 School of Mathematics and Statistics, Henan University of Science and Technology, Luoyang 471023, China
2 College of Vehicle & Motive Power Engineering, Henan University of Science and Technology, Luoyang 471023, China
Polymers 2017, 9(12), 699; https://doi.org/10.3390/polym9120699 - 11 Dec 2017
Cited by 4 | Viewed by 4974
Abstract
Polymer crystallization in manufacturing is a process where quiescent crystallization and flow-induced crystallization coexists, and heat/mass transfer on a macroscopic level interacts with crystal morphology evolution on a microscopic level. Previous numerical studies on polymer crystallization are mostly concentrated at a single scale; [...] Read more.
Polymer crystallization in manufacturing is a process where quiescent crystallization and flow-induced crystallization coexists, and heat/mass transfer on a macroscopic level interacts with crystal morphology evolution on a microscopic level. Previous numerical studies on polymer crystallization are mostly concentrated at a single scale; they only calculate macroscale parameters, e.g., temperature and relative crystallinity, or they only predict microstructure details, e.g., crystal morphology and mean size of crystals. The multi-scale numerical works that overcome these disadvantages are unfortunately based on quiescent crystallization, in which flow effects are neglected. The objective of this work is to build up a macro-micro model and a macro-micro algorithm to consider both the thermal and flow effects on the crystallization. Our macro-micro model couples two parts: mass and heat transfer of polymeric flow at the macroscopic level, and nucleation and growth of spherulites and shish-kebabs at the microscopic level. Our macro-micro algorithm is a hybrid finite volume/Monte Carlo method, in which the finite volume method is used at the macroscopic level to calculate the flow and temperature fields, while the Monte Carlo method is used at the microscopic level to capture the development of spherulites and shish-kebabs. The macro-micro model and the macro-micro algorithm are applied to simulate polymer crystallization in Couette flow. The effects of shear rate, shear time, and wall temperature on the crystal morphology and crystallization kinetics are also discussed. Full article
(This article belongs to the Special Issue Phase Behavior in Polymers)
Show Figures

Graphical abstract

16 pages, 4421 KiB  
Article
Entrapment of Autologous von Willebrand Factor on Polystyrene/Poly(methyl methacrylate) Demixed Surfaces
by Joanna Ward 1, Eimear Dunne 2, David Bishop 1, Adrian Boyd 1, Dermot Kenny 2 and Brian J. Meenan 1,*
1 Nanotechnology and Integrated Bioengineering Centre (NIBEC), Ulster University, Jordanstown BT37 0QB, UK
2 Royal College of Surgeons in Ireland, 123 St. Stephen’s Green, Dublin 2, Ireland
Polymers 2017, 9(12), 700; https://doi.org/10.3390/polym9120700 - 13 Dec 2017
Cited by 1 | Viewed by 4459
Abstract
Human platelets play a vital role in haemostasis, pathological bleeding and thrombosis. The haemostatic mechanism is concerned with the control of bleeding from injured blood vessels, whereby platelets interact with the damaged inner vessel wall to form a clot (thrombus) at the site [...] Read more.
Human platelets play a vital role in haemostasis, pathological bleeding and thrombosis. The haemostatic mechanism is concerned with the control of bleeding from injured blood vessels, whereby platelets interact with the damaged inner vessel wall to form a clot (thrombus) at the site of injury. This adhesion of platelets and their subsequent aggregation is dependent on the presence of the blood protein von Willebrand Factor (vWF). It is proposed here that the entrapment of vWF on a substrate surface offers the opportunity to assess an individual’s platelet function in a clinical diagnostic context. Spin coating from demixed solutions of polystyrene (PS) and poly(methyl methacrylate) (PMMA) onto glass slides has been shown previously to support platelet adhesion but the mechanism by which this interaction occurs, including the role of vWF, is not fully understood. In this work, we report a study of the interaction of platelets in whole blood with surfaces produced by spin coating from a solution of a weight/weight mixture of a 25% PS and 75% PMMA (25PS/75PMMA) in chloroform in the context of the properties required for their use as a Dynamic Platelet Function Assay (DPFA) substrate. Atomic Force Microscopy (AFM) indicates the presence of topographical features on the polymer demixed surfaces in the sub-micron to nanometer range. X-ray Photoelectron Spectroscopy (XPS) analysis confirms that the uppermost surface chemistry of the coatings is solely that of PMMA. The deliberate addition of various amounts of 50 μm diameter PS microspheres to the 25PS/75PMMA system has been shown to maintain the PMMA chemistry, but to significantly change the surface topography and to subsequently effect the scale of the resultant platelet interactions. By blocking specific platelet binding sites, it has been shown that their interaction with these surfaces is a consequence of the entrapment and build-up of vWF from the same whole blood sample. Full article
(This article belongs to the Special Issue Advance of Polymers Applied to Biomedical Applications: Biointerface)
Show Figures

Figure 1

17 pages, 7516 KiB  
Article
Modulating the Tg of Poly(alkylene succinate)s by Inserting Bio-Based Aromatic Units via Ring-Opening Copolymerization
by Juan Carlos Morales-Huerta, Antxon Martínez de Ilarduya and Sebastián Muñoz-Guerra *
Departament d’Enginyeria Química, Universitat Politècnica de Catalunya, ETSEIB, Diagonal 647, 08028 Barcelona, Spain
Polymers 2017, 9(12), 701; https://doi.org/10.3390/polym9120701 - 12 Dec 2017
Cited by 8 | Viewed by 5066
Abstract
Two series of aliphatic-aromatic copolyesters derived from succinic and 2,5-furandicarboxylic acids, and di-O-2-(hydroxyethyl) resorcinol as diol substituent of either 1,4-butanediol or ethylene glycol, respectively, were obtained by ring opening polymerization(ROP) performed in bulk and catalyzed by Sn(Oct)2. Cyclic oligomers [...] Read more.
Two series of aliphatic-aromatic copolyesters derived from succinic and 2,5-furandicarboxylic acids, and di-O-2-(hydroxyethyl) resorcinol as diol substituent of either 1,4-butanediol or ethylene glycol, respectively, were obtained by ring opening polymerization(ROP) performed in bulk and catalyzed by Sn(Oct)2. Cyclic oligomers of furandicarboxylate of di-O-2-(hydroxyethyl) resorcinol were successfully synthesized by high-dilution condensation, and then copolymerized with cyclic oligomers of either butylene or ethylene succinate. The synthesized resorcinol-containing succinate-furanoatecopolyesters had Mw oscillating between 50,000 and 30,000 g·mol−1 depending on composition, and they all displayed a nearly random microstructure. They showed an excellent thermal stability with onset decomposition temperatures near 300 °C. They are amorphous with Tg increasing monotonically with the content in resorcinol in both series with values ranging from −30 or −13 °C for butylene and ethylene-based copolyesters, respectively, up to around 45 °C. The resorcinol-containing succinate-furanoate copolyesters showed appreciable hydrolytic degradation when incubated for a few weeks in water under physiological conditions, a behavior that was notably enhanced in the presence of lipases. Full article
(This article belongs to the Special Issue Biodegradable and Biobased Polyesters)
Show Figures

Graphical abstract

11 pages, 2772 KiB  
Article
Bis(formylphenolato)cobalt(II)-Mediated Alternating Radical Copolymerization of tert-Butyl 2-Trifluoromethylacrylate with Vinyl Acetate
by Sanjib Banerjee 1,†, Ekaterina V. Bellan 2, Florence Gayet 2, Antoine Debuigne 3, Christophe Detrembleur 3, Rinaldo Poli 2,4,*, Bruno Améduri 1 and Vincent Ladmiral 1,*
1 Institut Charles Gerhardt Montpellier, University of Montpellier, CNRS, ENSCM, Place Eugène Bataillon, 34095 Montpellier CEDEX 5, France
2 Laboratoire de Chimie de Coordination (LCC), Université de Toulouse, CNRS, UPS, INPT, 205 route de Narbonne, BP 44099, 31077 Toulouse CEDEX 4, France
3 Center for Education and Research on Macromolecules (CERM), University of Liege, CESAM Research Unit, Sart-Tilman B6a, 4000 Liege, Belgium
4 Institut Universitaire de France, 1, rue Descartes, 75231 Paris CEDEX 05, France
Present address: Department of Chemistry, Indian Institute of Technology Bhilai, GEC Campus, Sejbahar, Raipur 492015, Chhattisgarh, India.
Polymers 2017, 9(12), 702; https://doi.org/10.3390/polym9120702 - 12 Dec 2017
Cited by 17 | Viewed by 5477
Abstract
The organometallic-mediated radical polymerization (OMRP) of vinyl acetate (VAc) and its OMR copolymerization (OMRcoP) with tert-butyl 2-trifluoromethylacrylate (MAF-TBE) mediated by Co(SAL)2 (SAL = 2-formylphenolato or deprotonated salicylaldehyde) produced relatively well-defined PVAc and poly(VAc-alt-MAF-TBE) copolymers at moderate temperature (<40 °C) [...] Read more.
The organometallic-mediated radical polymerization (OMRP) of vinyl acetate (VAc) and its OMR copolymerization (OMRcoP) with tert-butyl 2-trifluoromethylacrylate (MAF-TBE) mediated by Co(SAL)2 (SAL = 2-formylphenolato or deprotonated salicylaldehyde) produced relatively well-defined PVAc and poly(VAc-alt-MAF-TBE) copolymers at moderate temperature (<40 °C) in bulk. The resulting alternating copolymer was characterized by 1H-, 13C- and 19F-nuclear magnetic resonance (NMR) spectroscopies, and by size exclusion chromatography. The linear first-order kinetic plot, the linear evolutions of the molar mass with total monomer conversion, and the relatively low dispersity (Đ~1.55) of the resulting copolymers suggest that this cobalt complex provides some degree of control over the copolymerization of VAc and MAF-TBE. Compared to the previously investigated cobalt complex OMRP mediators having a fully oxygen-based first coordination sphere, this study emphasizes a few peculiarities of Co(SAL)2: a lower ability to trap radical chains as compared to Co(acac)2 and the absence of catalytic chain transfer reactions, which dominates polymerizations carried in the presence of 9-oxyphenalenone cobalt derivative. Full article
(This article belongs to the Special Issue Fluorinated Polymers)
Show Figures

Graphical abstract

11 pages, 3391 KiB  
Article
Proton Conductive Channel Optimization in Methanol Resistive Hybrid Hyperbranched Polyamide Proton Exchange Membrane
by Liying Ma 1,2, Jing Li 2,*, Jie Xiong 2,3, Guoxiao Xu 2, Zhao Liu 2 and Weiwei Cai 2,*
1 School of Chemistry and Materials Science, Guizhou Normal University, 116 Baoshan North Road, Guiyang 550001, China
2 Sustainable Energy Laboratory, Faculty of Materials Science and Chemistry, China University of Geosciences Wuhan, 388 Lumo RD, Wuhan 430074, China
3 College of Chemistry, Chemical Engineering and Material Science, Zaozhuang University, Zaozhuang 277160, China
Polymers 2017, 9(12), 703; https://doi.org/10.3390/polym9120703 - 14 Dec 2017
Cited by 8 | Viewed by 5814
Abstract
Based on a previously developed polyamide proton conductive macromolecule, the nano-scale structure of the self-assembled proton conductive channels (PCCs) is adjusted via enlarging the nano-scale pore size within the macromolecules. Hyperbranched polyamide macromolecules with different size are synthesized from different monomers to tune [...] Read more.
Based on a previously developed polyamide proton conductive macromolecule, the nano-scale structure of the self-assembled proton conductive channels (PCCs) is adjusted via enlarging the nano-scale pore size within the macromolecules. Hyperbranched polyamide macromolecules with different size are synthesized from different monomers to tune the nano-scale pore size within the macromolecules, and a series of hybrid membranes are prepared from these two micromoles to optimize the PCC structure in the proton exchange membrane. The optimized membrane exhibits methanol permeability low to 2.2 × 10−7 cm2/s, while the proton conductivity of the hybrid membrane can reach 0.25 S/cm at 80 °C, which was much higher than the value of the Nafion 117 membrane (0.192 S/cm). By considering the mechanical, dimensional, and the thermal properties, the hybrid hyperbranched polyamide proton exchange membrane (PEM) exhibits promising application potential in direct methanol fuel cells (DMFC). Full article
(This article belongs to the Special Issue Polymeric Membranes)
Show Figures

Graphical abstract

13 pages, 3422 KiB  
Article
The Abrasive Wear Resistance of the Segmented Linear Polyurethane Elastomers Based on a Variety of Polyols as Soft Segments
by Konrad Kwiatkowski 1,* and Małgorzata Nachman 2
1 Department of Mechanics and Machine Design Fundamentals, West Pomeranian University of Technology Szczecin, Al. Piastów 19, 70-310 Szczecin, Poland
2 Institute of Materials Science and Engineering, West Pomeranian University of Technology Szczecin, Al. Piastów 19, 70-310 Szczecin, Poland
Polymers 2017, 9(12), 705; https://doi.org/10.3390/polym9120705 - 12 Dec 2017
Cited by 42 | Viewed by 9192
Abstract
The presented results make an original contribution to the development of knowledge on the prediction and/or modeling of the abrasive wear properties of polyurethanes. A series of segmented linear polyurethane elastomers (PUR)—In which the hard segments consist of 4,4′-methylene bis(phenylisocyanate) and 1,4-butanodiol, whilst [...] Read more.
The presented results make an original contribution to the development of knowledge on the prediction and/or modeling of the abrasive wear properties of polyurethanes. A series of segmented linear polyurethane elastomers (PUR)—In which the hard segments consist of 4,4′-methylene bis(phenylisocyanate) and 1,4-butanodiol, whilst polyether, polycarbonate, or polyester polyols constitute the soft segments—Were synthesized and characterized. The hardness and wear performance as functions of the variable chemical composition of polyurethane elastomers were evaluated in order to define the relationship between studied factors. The microstructure was characterized in detail, including analysis of the hydrogen bonding by Fourier transformed infrared (FT-IR) spectroscopy and the phase structure by X-ray scattering (WAXS) and differential scanning calorimetry (DSC) methods. The presented studies provide the key features of the polymer composition affecting the abrasive resistance as well as attempts to explain the origin of the differences in the polyurethane elastomers’ performance. Full article
(This article belongs to the Special Issue Elastomers)
Show Figures

Graphical abstract

15 pages, 9241 KiB  
Article
An Insight into the Flammability of Some Bio-Based Polyesters
by Loïc Dumazert and Rodolphe Sonnier *
Ecole des Mines d’ Alès, Centre des Matériaux des Mines d’ Alès—Pôle Matériaux Polymères Avancés, 6 Avenue de Clavières, 30319 Alès CEDEX, France
Polymers 2017, 9(12), 706; https://doi.org/10.3390/polym9120706 - 12 Dec 2017
Cited by 3 | Viewed by 4253
Abstract
The heat release capacity of polymers can be generally predicted using a method based on the additivity of group contributions (the Van Krevelen approach). Nevertheless, there are some exceptions, evidencing that this approach is insufficient and must be completed. In this study, the [...] Read more.
The heat release capacity of polymers can be generally predicted using a method based on the additivity of group contributions (the Van Krevelen approach). Nevertheless, there are some exceptions, evidencing that this approach is insufficient and must be completed. In this study, the kinetic triplet accounting for the description of pyrolysis is identified for 11 polymers. Activation energy and the frequency factor are calculated using Kissinger’s method. Reaction models are chosen among the Avrami–Erofeev functions. The high flammability of poly(3-hydroxybutyrate) and the underestimation of its heat release capacity using the Van Krevelen approach are explained from these parameters. The results highlight the possibility of improving the model, using additional but easily accessible data. Full article
(This article belongs to the Special Issue Biodegradable and Biobased Polyesters)
Show Figures

Graphical abstract

16 pages, 9538 KiB  
Article
Electrosynthesis of Aromatic Poly(amide-amine) Films from Triphenylamine-Based Electroactive Compounds for Electrochromic Applications
by Sheng-Huei Hsiao * and Hsing-Yi Lu
Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, No. 1, Sec. 3, Chunghsiao East Rd., Taipei 10608, Taiwan
Polymers 2017, 9(12), 708; https://doi.org/10.3390/polym9120708 - 13 Dec 2017
Cited by 37 | Viewed by 8711
Abstract
Two electropolymerizable monomers with a methoxytriphenylamine core linked via amide groups to two triphenylamine (TPA) or N-phenylcarbazole (NPC) terminal groups, namely 4,4′-bis(4-diphenylaminobenzamido)-4′′-methoxytriphenylamine (MeOTPA-(TPA)2) and 4,4′-bis(4-(carbazol-9-yl)benzamido)-4′′-methoxytriphenylamine (MeOTPA-(NPC)2), were synthesized and characterized by FTIR and 1H NMR spectroscopy, mass [...] Read more.
Two electropolymerizable monomers with a methoxytriphenylamine core linked via amide groups to two triphenylamine (TPA) or N-phenylcarbazole (NPC) terminal groups, namely 4,4′-bis(4-diphenylaminobenzamido)-4′′-methoxytriphenylamine (MeOTPA-(TPA)2) and 4,4′-bis(4-(carbazol-9-yl)benzamido)-4′′-methoxytriphenylamine (MeOTPA-(NPC)2), were synthesized and characterized by FTIR and 1H NMR spectroscopy, mass spectrometry, and cyclic voltammetry. The electrochemical polymerization reactions of these MeOTPA-cored monomers over indium tin oxide (ITO) electrode allow the generation of electroactive poly(amide-amine) films. The electro-generated polymer films exhibited reversible redox processes and multi-colored electrochromic behaviors upon electro-oxidation, together with moderate coloration efficiency and cycling stability. The optical density changes (ΔOD) were observed in the range of 0.18–0.68 at specific absorption maxima, with the calculated coloration efficiencies of 42–123 cm2/C. Single-layer electrochromic devices using the electrodeposited polymer films as active layers were fabricated for the preliminary investigation of their electrochromic applications. Full article
(This article belongs to the Special Issue Polymeric Materials for Optical Applications)
Show Figures

Graphical abstract

26 pages, 11547 KiB  
Article
Morphology, Nucleation, and Isothermal Crystallization Kinetics of Poly(ε-caprolactone) Mixed with a Polycarbonate/MWCNTs Masterbatch
by Thandi P. Gumede 1, Adriaan S. Luyt 2,*, Mohammad K. Hassan 2, Ricardo A. Pérez-Camargo 3, Agnieszka Tercjak 4 and Alejandro J. Müller 3,5,*
1 Department of Chemistry, University of the Free State (Qwaqwa Campus), Private Bag X13, Phuthaditjhaba 9866, South Africa
2 Center for Advanced Materials, Qatar University, P.O. Box 2713 Doha, Qatar
3 Polymat and Polymer Science and Technology Department, Faculty of Chemistry, University of the Basque Country UPV/EHU, Paseo Manuel de Lardizabal 3, 20018 Donostia-San Sebastián, Spain
4 Group ‘Materials + Technologies’ (GMT), Department of Chemical and Environmental Engineering, Faculty of Engineering, Gipuzkoa, University of the Basque Country UPV/EHU, 20018 Donostia-San Sebastián, Spain
5 Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Spain
Polymers 2017, 9(12), 709; https://doi.org/10.3390/polym9120709 - 13 Dec 2017
Cited by 23 | Viewed by 7639
Abstract
In this study, nanocomposites were prepared by melt blending poly (ε-caprolactone) (PCL) with a (polycarbonate (PC)/multi-wall carbon nanotubes (MWCNTs)) masterbatch in a twin-screw extruder. The nanocomposites contained 0.5, 1.0, 2.0, and 4.0 wt % MWCNTs. Even though PCL and PC have been reported [...] Read more.
In this study, nanocomposites were prepared by melt blending poly (ε-caprolactone) (PCL) with a (polycarbonate (PC)/multi-wall carbon nanotubes (MWCNTs)) masterbatch in a twin-screw extruder. The nanocomposites contained 0.5, 1.0, 2.0, and 4.0 wt % MWCNTs. Even though PCL and PC have been reported to be miscible, our DSC (Differential Scanning Calorimetry), SAXS (Small Angle X-ray Scattering), and WAXS (Wide Angle X-ray Scattering) results showed partial miscibility, where two phases were formed (PC-rich and PCL-rich phases). In the PC-rich phase, the small amount of PCL chains included within this phase plasticized the PC component and the PC-rich phase was therefore able to crystallize. In contrast, in the PCL-rich phase the amount of PC chains present generates changes in the glass transition temperature of the PCL phase that were much smaller than those predicted by the Fox equation. The presence of two phases was corroborated by SEM, TEM, and AFM observations where a fair number of MWCNTs diffused from the PC-rich phase to the PCL-rich phase, even though there were some MWCNTs agglomerates confined to PC-rich droplets. Standard DSC measurements demonstrated that the MWCNTs nucleation effects are saturated at a 1 wt % MWCNT concentration on the PCL-rich phase. This is consistent with the dielectric percolation threshold, which was found to be between 0.5 and 1 wt % MWCNTs. However, the nucleating efficiency was lower than literature reports for PCL/MWCNTs, due to limited phase mixing between the PC-rich and the PCL-rich phases. Isothermal crystallization experiments performed by DSC showed an increase in the overall crystallization kinetics of PCL with increases in MWCNTs as a result of their nucleating effect. Nevertheless, the crystallinity degree of the nanocomposite containing 4 wt % MWCNTs decreased by about 15% in comparison to neat PCL. This was attributed to the presence of the PC-rich phase, which was able to crystallize in view of the plasticization effect of the PCL component, since as the MWCNT content increases, the PC content in the blend also increases. The thermal conductivities (i.e., 4 wt % MWCNTs) were enhanced by 20% in comparison to the neat material. The nanocomposites prepared in this work could be employed in applications were electrical conductivity is required, as well as lightweight and tailored mechanical properties. Full article
(This article belongs to the Special Issue Polymer Nanocomposites)
Show Figures

Graphical abstract

16 pages, 3703 KiB  
Article
Photo Irradiation-Induced Core Crosslinked Poly(ethylene glycol)-block-poly(aspartic acid) Micelles: Optimization of Block Copolymer Synthesis and Characterization of Core Crosslinked Micelles
by Kouichi Shiraishi 1, Shin-ichi Yusa 2, Masanori Ito 2, Keita Nakai 2 and Masayuki Yokoyama 1,*
1 Medical Engineering Laboratory, Research Center for Medical Sciences, The Jikei University School of Medicine, 163-1, Kashiwashita, Kashiwa, Chiba 277-0004, Japan
2 Department of Applied Chemistry, Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2280, Japan
Polymers 2017, 9(12), 710; https://doi.org/10.3390/polym9120710 - 14 Dec 2017
Cited by 6 | Viewed by 5243
Abstract
We used photo irradiation to design core crosslinked polymeric micelles whose only significant physico-chemical change was in their physico-chemical stability, which helps elucidate poly(ethylene glycol) (PEG)-related immunogenicity. Synthetic routes and compositions of PEG-b-poly(aspartic acid) block copolymers were optimized with the control [...] Read more.
We used photo irradiation to design core crosslinked polymeric micelles whose only significant physico-chemical change was in their physico-chemical stability, which helps elucidate poly(ethylene glycol) (PEG)-related immunogenicity. Synthetic routes and compositions of PEG-b-poly(aspartic acid) block copolymers were optimized with the control of n-alkyl chain length and photo-sensitive chalcone moieties. The conjugation ratio between n-alkyl chain and the chalcone moieties was controlled, and upon the mild photo irradiation of polymeric micelles, permanent crosslink proceeded in the micelle cores. In the optimized condition, the core crosslinked (CCL) micelles exhibited no dissociation while the non-CCL micelles exhibited dissociation. These results indicate that the photo-crosslinking reactions in the inner core were successful. A gel-permeation chromatography (GPC) measurement revealed a difference between the micellar-formation stability of CCL micelles and that of the non-CCL micelles. GPC experiments revealed that the CCL micelles were more stable than the non-CCL micelles. Our research also revealed that photo-crosslinking reactions did not change the core property for drug encapsulation. In conclusion, the prepared CCL micelles exhibited the same diameter, the same formula, and the same inner-core properties for drug encapsulation as did the non-CCL micelles. Moreover, the CCL micelles exhibited non-dissociable micelle formation, while the non-CCL micelles exhibited dissociation into single block copolymers. Full article
(This article belongs to the Special Issue Polymer Micelles)
Show Figures

Graphical abstract

16 pages, 9299 KiB  
Article
The Reaction between Furfuryl Alcohol and Model Compound of Protein
by Jiankun Liang 1,2,†, Zhigang Wu 3,†, Hong Lei 1,*, Xuedong Xi 1, Taohong Li 1 and Guanben Du 1,*
1 Yunnan Provincial Key Laboratory of Wood Adhesives and Glued Products, Southwest Forestry University, Kunming 650224, China
2 Material Science and Technology College, Beijing Forestry University, Beijing 100083, China
3 College of Forestry, Guizhou University, Guiyang 550025, China
These authors contributed equally to this work.
Polymers 2017, 9(12), 711; https://doi.org/10.3390/polym9120711 - 14 Dec 2017
Cited by 19 | Viewed by 6250
Abstract
To guide the preparation of protein-based adhesive, especially the soy-based adhesive, the reaction between a simple dipeptide N-(2)-l-alanyl-l-glutamine (AG), being used as a model compound of protein, and its cross-linker furfuryl alcohol were studied in this paper. The [...] Read more.
To guide the preparation of protein-based adhesive, especially the soy-based adhesive, the reaction between a simple dipeptide N-(2)-l-alanyl-l-glutamine (AG), being used as a model compound of protein, and its cross-linker furfuryl alcohol were studied in this paper. The products that were prepared with furfuryl alcohol and AG under different pHs were analyzed by ESI-MS, 13C NMR, and FT-IR. It was found that the medium environment had great effects on the competition of the co-condensation reaction between furfuryl alcohol and AG and self-condensation reaction of furfuryl alcohol molecules in the mixing system with furfuryl alcohol and AG. Under alkaline conditions, both co- and self-condensation were not obviously detected. Only when the value of pH was higher than 11, were a few co-condensation reaction products gotten. The reaction occurred mainly between furfuryl alcohol and the primary amido groups of AG. Under acid conditions, both co- and self-condensation were observed. The more acid the preparation conditions were, the easier to be observed the self-condensation of furfuryl alcohol molecules would be than the co-condensation between furfuryl alcohol and AG. When the value of pH was higher than 5, both co- and self-condensation were not outstanding. In this study, under pH 3, the co- and self-condensation found equilibrium. There was a great possibility for the primary amido and aliphatic amino groups of AG molecules to react with furfuryl alcohol molecules. No reaction was detected between the secondary amido groups of AG and furfuryl alcohol. Full article
(This article belongs to the Collection Polymeric Adhesives)
Show Figures

Figure 1

13 pages, 6221 KiB  
Article
Effects of Matrix Modification on the Mechanical Properties of Wood–Polypropylene Composites
by Shunmin Yi 1, Shihua Xu 1, Yiqun Fang 1, Haigang Wang 1,* and Qingwen Wang 2,*
1 Key Laboratory of Bio-Based Material Science and Technology (Ministry of Education), Northeast Forestry University, Harbin 150040, China
2 College of Materials and Energy, South China Agricultural University, Guangzhou 510642, China
Polymers 2017, 9(12), 712; https://doi.org/10.3390/polym9120712 - 14 Dec 2017
Cited by 22 | Viewed by 5966
Abstract
Polypropylene (PP) modified with two reactive monomers, divinyl benzene (DVB) and maleic anhydride (MAH), was used as the matrix to prepare wood–polypropylene composites to improve interfacial compatibility. The effects of the co-modified PP matrices with different DVB concentrations on the mechanical properties of [...] Read more.
Polypropylene (PP) modified with two reactive monomers, divinyl benzene (DVB) and maleic anhydride (MAH), was used as the matrix to prepare wood–polypropylene composites to improve interfacial compatibility. The effects of the co-modified PP matrices with different DVB concentrations on the mechanical properties of the composites were evaluated. Compared with unmodified composites and the composites containing a coupling agent, the composites modified with MAH only, and that with both MAH and DVB, improved the tensile, flexural, and impact strengths. Interestingly, adding a small amount of DVB (0.4%) resulted in significant increase in impact strength, relative to that of the composites modified with MAH only. Dynamic mechanical analysis and fracture morphology analysis of the modified composites also suggested an improvement in interfacial adhesion owing to the matrix modification. Full article
Show Figures

Graphical abstract

18 pages, 8044 KiB  
Article
The Effect of Plasma Treated PLGA/MWCNTs-COOH Composite Nanofibers on Nerve Cell Behavior
by Jing Wang 1,2, Nuan Chen 2, Seeram Ramakrishna 2,3, Lingling Tian 2,* and Xiumei Mo 1,*
1 College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620, China
2 Center for Nanofibers and Nanotechnology, E3-05-14, Department of Mechanical Engineering, Faculty of Engineering, National University of Singapore, 2 Engineering Drive 3, Singapore 117576, Singapore
3 Guangdong-Hongkong-Macau Institute of CNS Regeneration (GHMICR), Jinan University, Guangzhou 510632, China
Polymers 2017, 9(12), 713; https://doi.org/10.3390/polym9120713 - 14 Dec 2017
Cited by 36 | Viewed by 6031
Abstract
Electrospun nanofibrous scaffolds which can mimic the architecture of the natural extracellular matrix (ECM) are potential candidates for peripheral nerve repair application. Multi-walled carbon nanotubes (MWCNTs) are used in peripheral nerve repair due to their ability to promote neurite extension and support neural [...] Read more.
Electrospun nanofibrous scaffolds which can mimic the architecture of the natural extracellular matrix (ECM) are potential candidates for peripheral nerve repair application. Multi-walled carbon nanotubes (MWCNTs) are used in peripheral nerve repair due to their ability to promote neurite extension and support neural network formation. In this study, surface-modified nanofibrous scaffolds composed of poly(lactic-co-glycolic acid) (PLGA) and various ratios of carboxyl-modified MWCNTs (MWCNTs-COOH) (PC0, PC2, PC4 and PC8) were fabricated by electrospinning. The effects of MWCNTs-COOH on the fibers’ morphology, diameter distribution, mechanical properties and surface hydrophilicity were characterized by Scanning Electron Microscopy (SEM), ImageJ software, tensile testing and water contact angle. Furthermore, air plasma treatment was applied to improve the surface hydrophilicity of the scaffolds, and the optimal treatment condition was determined in terms of surface morphology, water contact angle and PC12 cell adhesion. Plasma treated nanofibers (p-PC0, p-PC2, p-PC4 and p-PC8) under optimal treatment conditions were used for further study. PC12 cell proliferation and differentiation were both improved by the addition of MWCNTs-COOH in scaffolds. Additionally, the proliferation and maturation of Schwann cells were enhanced on scaffolds containing MWCNTs-COOH. The neurite outgrowth of rat dorsal root ganglia (DRG) neurons was promoted on MWCNTs-COOH-containing scaffolds, and those cultured on p-PC8 scaffolds showed elongated neurites with a length up to 78.27 μm after 3 days culture. Our results suggested that plasma treated nanofibers under appropriate conditions were able to improve cell attachment. They also demonstrated that plasma treated scaffolds containing MWCNTs-COOH, especially the p-PC8 nanofibrous scaffold could support the proliferation, differentiation, maturation and neurite extension of PC12 cells, Schwann cells and DRG neurons. Therefore, p-PC8 could be a potential candidate for peripheral nerve regeneration application. Full article
(This article belongs to the Special Issue Electrospinning of Nanofibres)
Show Figures

Graphical abstract

11 pages, 2964 KiB  
Article
Ultra-Stretchable Piezoelectric Nanogenerators via Large-Scale Aligned Fractal Inspired Micro/Nanofibers
by Yongqing Duan 1,2, Yajiang Ding 1,2, Jing Bian 1,2, Zhoulong Xu 1,2, Zhouping Yin 1,2 and Yongan Huang 1,2,*
1 State Key Laboratory of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
2 Flexible Electronics Research Center, Huazhong University of Science and Technology, Wuhan 430074, China
Polymers 2017, 9(12), 714; https://doi.org/10.3390/polym9120714 - 15 Dec 2017
Cited by 30 | Viewed by 8316
Abstract
Stretchable nanogenerators that directly generate electricity are promising for a wide range of applications in wearable electronics. However, the stretchability of the devices has been a long-standing challenge. Here we present a newly-designed ultra-stretchable nanogenerator based on fractal-inspired piezoelectric nanofibers and liquid metal [...] Read more.
Stretchable nanogenerators that directly generate electricity are promising for a wide range of applications in wearable electronics. However, the stretchability of the devices has been a long-standing challenge. Here we present a newly-designed ultra-stretchable nanogenerator based on fractal-inspired piezoelectric nanofibers and liquid metal electrodes that can withstand strain as large as 200%. The large-scale fractal poly(vinylidene fluoride) (PVDF) micro/nanofibers are fabricated by combination of helix electrohydrodynamic printing (HE-Printing) and buckling-driven self-assembly. HE-Printing exploits “whipping/buckling” instability of electrospinning to deposit serpentine fibers with diverse geometries in a programmable, accurately positioned, and individually-controlled manner. Self-organized buckling utilizes the driven force from the prestrained elastomer to assemble serpentine fibers into ultra-stretchable fractal inspired architecture. The nanogenerator with embedded fractal PVDF fibers and liquid-metal microelectrodes demonstrates high stretchability (>200%) and electricity (currents >200 nA), it can harvest energy from all directions by arbitrary mechanical motion, and the rectified output has been applied to charge the commercial capacitor and drive LEDs, which enables wearable electronics applications in sensing and energy harvesting. Full article
(This article belongs to the Special Issue Soft Materials and Systems)
Show Figures

Graphical abstract

27 pages, 3001 KiB  
Article
Presenting Precision Glycomacromolecules on Gold Nanoparticles for Increased Lectin Binding
by Sophia Boden 1, Kristina G. Wagner 2, Matthias Karg 2 and Laura Hartmann 1,*
1 Institute of Organic Chemistry and Macromolecular Chemistry, Heinrich-Heine-University Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
2 Institute of Physical Chemistry, Heinrich-Heine-University Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
Polymers 2017, 9(12), 716; https://doi.org/10.3390/polym9120716 - 14 Dec 2017
Cited by 32 | Viewed by 9517 | Correction
Abstract
Glyco-functionalized gold nanoparticles have great potential as biosensors and as inhibitors due to their increased binding to carbohydrate-recognizing receptors such as the lectins. Here we apply previously developed solid phase polymer synthesis to obtain a series of precision glycomacromolecules that allows for straightforward [...] Read more.
Glyco-functionalized gold nanoparticles have great potential as biosensors and as inhibitors due to their increased binding to carbohydrate-recognizing receptors such as the lectins. Here we apply previously developed solid phase polymer synthesis to obtain a series of precision glycomacromolecules that allows for straightforward variation of their chemical structure as well as functionalization of gold nanoparticles by ligand exchange. A novel building block is introduced allowing for the change of spacer building blocks within the macromolecular scaffold going from an ethylene glycol unit to an aliphatic spacer. Furthermore, the valency and overall length of the glycomacromolecule is varied. All glyco-functionalized gold nanoparticles show high degree of functionalization along with high stability in buffer solution. Therefore, a series of measurements applying UV-Vis spectroscopy, dynamic light scattering (DLS) and surface plasmon resonance (SPR) were performed studying the aggregation behavior of the glyco-functionalized gold nanoparticles in presence of model lectin Concanavalin A. While the multivalent presentation of glycomacromolecules on gold nanoparticles (AuNPs) showed a strong increase in binding compared to the free ligands, we also observed an influence of the chemical structure of the ligand such as its valency or hydrophobicity on the resulting lectin interactions. The straightforward variation of the chemical structure of the precision glycomacromolecule thus gives access to tailor-made glyco-gold nanoparticles (glyco-AuNPs) and fine-tuning of their lectin binding properties. Full article
(This article belongs to the Special Issue Polymers and Block Copolymers at Interfaces and Surfaces)
Show Figures

Graphical abstract

11 pages, 1913 KiB  
Article
Preparation of Copolymer-Based Nanoparticles with Broad-Spectrum Antimicrobial Activity
by Yang Li 1, Pingxiong Cai 2, Zhang-fa Tong 1, Huining Xiao 3 and Yuanfeng Pan 1,*
1 Guangxi Key Lab of Petrochemical Resource Processing and Process Intensification Technology, School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China
2 College of Petroleum and Chemical Engineering, Qinzhou University, Qinzhou 535006, China
3 Department of Chemical Engineering, University of New Brunswick, Fredericton, NB E3B 5A3, Canada
Polymers 2017, 9(12), 717; https://doi.org/10.3390/polym9120717 - 15 Dec 2017
Cited by 7 | Viewed by 4967
Abstract
Polyacrylate and guanidine-based nanoparticles which involve acrylate monomers and glycidyl methacrylate modified oligo-guanidine were prepared by a seeded semi-continuous emulsion polymerization. The results from transmission electron microscope and dynamic light scattering measurements showed that the nanoparticles were spherical in shape and the particle [...] Read more.
Polyacrylate and guanidine-based nanoparticles which involve acrylate monomers and glycidyl methacrylate modified oligo-guanidine were prepared by a seeded semi-continuous emulsion polymerization. The results from transmission electron microscope and dynamic light scattering measurements showed that the nanoparticles were spherical in shape and the particle size was in the range of 80–130 nm. Antimicrobial experiments were performed with two types of bacteria, Gram-negative (Escherichia coli, ATCC 8739) and Gram-positive (Staphylococcus aureus, ATCC 6538). The as-synthesized cationic nanoparticles exhibited effective antimicrobial activities on Escherichia coli and Staphylococcus aureus with the minimal inhibitory concentrations at 8 μg/mL and 4 μg/mL, respectively. The mechanism of action of the resulted nanoparticles against these bacteria was revealed by the scanning electron microscopic observation. In addition, the films consisting of latex nanoparticles are non-leaching antimicrobial materials with excellent antimicrobial activity, which indicates the polymers could preserve their antimicrobial activity for long-term effectiveness. Full article
(This article belongs to the Special Issue Antimicrobial Polymers)
Show Figures

Graphical abstract

14 pages, 5298 KiB  
Article
PVDF Membrane Morphology—Influence of Polymer Molecular Weight and Preparation Temperature
by Monika Haponska 1,2, Anna Trojanowska 1,2,*, Adrianna Nogalska 1,2, Renata Jastrzab 2, Tania Gumi 1 and Bartosz Tylkowski 3,*
1 Departament d’ Enginyeria Química, Universitat Rovira i Virgili, Av. dels Països Catalans 26, 43007 Tarragona, Spain
2 Faculty of Chemistry, A. Mickiewicz University, Umultowska 89b, 61-614 Poznan, Poland
3 Centre Tecnològic de la Química de Catalunya, Carrer de Marcel·lí Domingo, 43007 Tarragona, Spain
Polymers 2017, 9(12), 718; https://doi.org/10.3390/polym9120718 - 15 Dec 2017
Cited by 62 | Viewed by 16199
Abstract
In this study, we successfully prepared nine non-woven, supported polyvinylidene fluoride (PVDF) membranes, using a phase inversion precipitation method, starting from a 15 wt % PVDF solution in N-methyl-2-pyrrolidone. Various membrane morphologies were obtained by using (1) PVDF polymers, with diverse molecular [...] Read more.
In this study, we successfully prepared nine non-woven, supported polyvinylidene fluoride (PVDF) membranes, using a phase inversion precipitation method, starting from a 15 wt % PVDF solution in N-methyl-2-pyrrolidone. Various membrane morphologies were obtained by using (1) PVDF polymers, with diverse molecular weights ranging from 300 to 700 kDa, and (2) different temperature coagulation baths (20, 40, and 60 ± 2 °C) used for the film precipitation. An environmental scanning electron microscope (ESEM) was used for surface and cross-section morphology characterization. An atomic force microscope (AFM) was employed to investigate surface roughness, while a contact angle (CA) instrument was used for membrane hydrophobicity studies. Fourier transform infrared spectroscopy (FTIR) results show that the fabricated membranes are formed by a mixture of TGTG’ chains, in α phase crystalline domains, and all-TTTT trans planar zigzag chains characteristic to β phase. Moreover, generated results indicate that the phases’ content and membrane morphologies depend on the polymer molecular weight and conditions used for the membranes’ preparation. The diversity of fabricated membranes could be applied by the End User Industries for different applications. Full article
(This article belongs to the Special Issue Polymeric Membranes)
Show Figures

Graphical abstract

17 pages, 3261 KiB  
Article
pH-Responsive Host–Guest Complexation in Pillar[6]arene-Containing Polyelectrolyte Multilayer Films
by Henning Nicolas 1, Bin Yuan 2, Jiangfei Xu 2, Xi Zhang 2 and Monika Schönhoff 1,*
1 University of Muenster, Institute of Physical Chemistry, Correnstraße 28/30, 48149 Münster, Germany
2 Key Laboratory of Organic Optoelectronics & Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing 100084, China
Polymers 2017, 9(12), 719; https://doi.org/10.3390/polym9120719 - 16 Dec 2017
Cited by 12 | Viewed by 7051
Abstract
A water-soluble, anionic pillar[6]arene derivative (WP6) is applied as monomeric building block for the layer-by-layer self-assembly of thin polyelectrolyte multilayer films, and its pH-dependent host–guest properties are employed for the reversible binding and release of a methylviologen guest molecule. The alternating assembly of [...] Read more.
A water-soluble, anionic pillar[6]arene derivative (WP6) is applied as monomeric building block for the layer-by-layer self-assembly of thin polyelectrolyte multilayer films, and its pH-dependent host–guest properties are employed for the reversible binding and release of a methylviologen guest molecule. The alternating assembly of anionic WP6 and cationic diazo resin (DAR) is monitored in-situ by a dissipative quartz crystal microbalance (QCM-D). In solution, the formation of a stoichiometric inclusion complex of WP6 and cationic methylviologen (MV) as guest molecule is investigated by isothermal titration calorimetry and UV-vis spectroscopy, respectively, and attributed to electrostatic interactions as primary driving force of the host–guest complexation. Exposure of WP6-containing multilayers to MV solution reveals a significant decrease of the resonance frequency, confirming MV binding. Subsequent release is achieved by pH lowering, decreasing the host–guest interactions. The dissociation of the host–guest complex, release of the guest from the film, as well as full reversibility of the binding event are identified by QCM-D. In addition, UV-vis data quantify the surface coverage of the guest molecule in the film after loading and release, respectively. These findings establish the pH-responsiveness of WP6 as a novel external stimulus for the reversible guest molecule recognition in thin films. Full article
(This article belongs to the Special Issue Host-Guest Polymer Complexes)
Show Figures

Graphical abstract

13 pages, 5837 KiB  
Communication
Individual Impact of Distinct Polysialic Acid Chain Lengths on the Cytotoxicity of Histone H1, H2A, H2B, H3 and H4
by Kristina Zlatina 1, Thomas Lütteke 2,† and Sebastian P. Galuska 1,*
1 Institute of Reproductive Biology, Leibniz Institute for Farm Animal Biology (FBN), Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany
2 Institute of Veterinary Physiology and Biochemistry, Justus-Liebig-University, Frankfurter Str. 100, 35392 Giessen, Germany
Current address: ITech Progress GmbH, Donnersbergweg 4, 67059 Ludwigshafen, Germany.
Polymers 2017, 9(12), 720; https://doi.org/10.3390/polym9120720 - 16 Dec 2017
Cited by 23 | Viewed by 5758
Abstract
Neutrophils are able to neutralize pathogens by phagocytosis, by the release of antimicrobial components, as well as by the formation of neutrophil extracellular traps (NETs). The latter possibility is a DNA-meshwork mainly consisting of highly concentrated extracellular histones, which are not only toxic [...] Read more.
Neutrophils are able to neutralize pathogens by phagocytosis, by the release of antimicrobial components, as well as by the formation of neutrophil extracellular traps (NETs). The latter possibility is a DNA-meshwork mainly consisting of highly concentrated extracellular histones, which are not only toxic for pathogens, but also for endogenous cells triggering several diseases. To reduce the negative outcomes initiated by extracellular histones, different approaches like antibodies against histones, proteases, and the polysaccharide polysialic acid (polySia) were discussed. We examined whether each of the individual histones is a binding partner of polySia, and analyzed their respective cytotoxicity in the presence of this linear homopolymer. Interestingly, all of the histones (H1, H2A, H2B, H3, and H4) seem to interact with α2,8-linked sialic acids. However, we observed strong differences regarding the required chain length of polySia to bind histone H1, H2A, H2B, H3, and H4. Moreover, distinct degrees of polymerization were necessary to act as a cytoprotective agent in the presence of the individual histones. In sum, the outlined results described polySia-based strategies to bind and/or to reduce the cytotoxicity of individual histones using distinct polySia chain length settings. Full article
Show Figures

Graphical abstract

13 pages, 5695 KiB  
Article
Aerogels from Chitosan Solutions in Ionic Liquids
by Gonzalo Santos-López 1, Waldo Argüelles-Monal 2, Elizabeth Carvajal-Millan 1, Yolanda L. López-Franco 1, Maricarmen T. Recillas-Mota 2 and Jaime Lizardi-Mendoza 1,*
1 Grupo de Investigación en Biopolímeros—CTAOA. Centro de Investigación en Alimentación y Desarrollo, A.C., Hermosillo, Sonora 83304, Mexico
2 Polímeros Naturales. Centro de Investigación en Alimentación y Desarrollo, A.C., Unidad Guaymas, Guaymas, Sonora 85480, Mexico
Polymers 2017, 9(12), 722; https://doi.org/10.3390/polym9120722 - 16 Dec 2017
Cited by 34 | Viewed by 7003
Abstract
Chitosan aerogels conjugates the characteristics of nanostructured porous materials, i.e., extended specific surface area and nano scale porosity, with the remarkable functional properties of chitosan. Aerogels were obtained from solutions of chitosan in ionic liquids (ILs), 1-butyl-3-methylimidazolium acetate (BMIMAc), and 1-ethyl-3-methyl-imidazolium acetate (EMIMAc), [...] Read more.
Chitosan aerogels conjugates the characteristics of nanostructured porous materials, i.e., extended specific surface area and nano scale porosity, with the remarkable functional properties of chitosan. Aerogels were obtained from solutions of chitosan in ionic liquids (ILs), 1-butyl-3-methylimidazolium acetate (BMIMAc), and 1-ethyl-3-methyl-imidazolium acetate (EMIMAc), in order to observe the effect of the solvent in the structural characteristics of this type of materials. The process of elaboration of aerogels comprised the formation of physical gels through anti-solvent vapor diffusion, liquid phase exchange, and supercritical CO2 drying. The aerogels maintained the chemical identity of chitosan according to Fourier transform infrared spectrophotometer (FT-IR) spectroscopy, indicating the presence of their characteristic functional groups. The internal structure of the obtained aerogels appears as porous aggregated networks in microscopy images. The obtained materials have specific surface areas over 350 m2/g and can be considered mesoporous. According to swelling experiments, the chitosan aerogels could absorb between three and six times their weight of water. However, the swelling and diffusion coefficient decreased at higher temperatures. The structural characteristics of chitosan aerogels that are obtained from ionic liquids are distinctive and could be related to solvation dynamic at the initial state. Full article
(This article belongs to the Special Issue Advances in Chitin/Chitosan Characterization and Applications)
Show Figures

Graphical abstract

14 pages, 5025 KiB  
Article
Synthesis of Isotactic-block-Syndiotactic Poly(methyl Methacrylate) via Stereospecific Living Anionic Polymerizations in Combination with Metal-Halogen Exchange, Halogenation, and Click Reactions
by Naoya Usuki 1, Kotaro Satoh 1,2,* and Masami Kamigaito 1,*
1 Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan
2 Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
Polymers 2017, 9(12), 723; https://doi.org/10.3390/polym9120723 - 16 Dec 2017
Cited by 9 | Viewed by 10687
Abstract
Isotactic (it-) and syndiotactic (st-) poly(methyl methacrylate)s (PMMAs) form unique crystalline stereocomplexes, which are attractive from both fundamental and application viewpoints. This study is directed at the efficient synthesis of it- and st-stereoblock (it-b [...] Read more.
Isotactic (it-) and syndiotactic (st-) poly(methyl methacrylate)s (PMMAs) form unique crystalline stereocomplexes, which are attractive from both fundamental and application viewpoints. This study is directed at the efficient synthesis of it- and st-stereoblock (it-b-st-) PMMAs via stereospecific living anionic polymerizations in combination with metal-halogen exchange, halogenation, and click reactions. The azide-capped it-PMMA was prepared by living anionic polymerization of MMA, which was initiated with t-BuMgBr in toluene at –78 °C, and was followed by termination using CCl4 as the halogenating agent in the presence of a strong Lewis base and subsequent azidation with NaN3. The alkyne-capped st-PMMA was obtained by living anionic polymerization of MMA, which was initiated via an in situ metal-halogen exchange reaction between 1,1-diphenylhexyl lithium and an α-bromoester bearing a pendent silyl-protected alkyne group. Finally, copper-catalyzed alkyne-azide cycloaddition (CuAAC) between these complimentary pairs of polymers resulted in a high yield of it-b-st-PMMAs, with controlled molecular weights and narrow molecular weight distributions. The stereocomplexation was evaluated in CH3CN and was affected by the block lengths and ratios. Full article
(This article belongs to the Special Issue Living Polymerization)
Show Figures

Graphical abstract

16 pages, 1942 KiB  
Article
Novel Random PBS-Based Copolymers Containing Aliphatic Side Chains for Sustainable Flexible Food Packaging
by Giulia Guidotti 1, Michelina Soccio 1,*, Valentina Siracusa 2, Massimo Gazzano 3, Elisabetta Salatelli 4, Andrea Munari 1 and Nadia Lotti 1,*
1 Civil, Chemical, Environmental and Materials Engineering Department, University of Bologna, Via Terracini 28, 40131 Bologna, Italy
2 Department of Chemical Science, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
3 Organic Synthesis and Photoreactivity Institute, ISOF-CNR, Via Gobetti 101, 40129 Bologna, Italy
4 Department of Industrial Chemistry “Toso Montanari”, University of Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
Polymers 2017, 9(12), 724; https://doi.org/10.3390/polym9120724 - 16 Dec 2017
Cited by 66 | Viewed by 7552
Abstract
In the last decade, there has been an increased interest from the food packaging industry toward the development and application of biodegradable and biobased plastics, to contribute to the sustainable economy and to reduce the huge environmental problem afflicting the planet. In this [...] Read more.
In the last decade, there has been an increased interest from the food packaging industry toward the development and application of biodegradable and biobased plastics, to contribute to the sustainable economy and to reduce the huge environmental problem afflicting the planet. In this framework, the present paper describes the synthesis of novel PBS (poly(butylene succinate))-based random copolymers with different composition containing glycol sub-units characterized by alkyl pendant groups of different length. The prepared samples were subjected to molecular, thermal, diffractometric and mechanical characterization. The barrier performances to O2, CO2 and N2 gases were also evaluated, envisioning for these new materials an application in food packaging. The presence of the side alkyl groups did not alter the thermal stability, whereas it significantly reduced the sample crystallinity degree, making these materials more flexible. The barrier properties were found to be worse than PBS; however, some of them were comparable to, or even better than, those of Low Density Polyethylene (LDPE), widely employed for flexible food packaging. The entity of variations in the final properties due to copolymerization were more modest in the case of the co-unit with short side methyl groups, which, when included in the PBS crystal lattice, causes a more modest decrement of crystallinity degree. Full article
(This article belongs to the Special Issue Biodegradable and Biobased Polyesters)
Show Figures

Figure 1

11 pages, 2545 KiB  
Article
Characterization of Wood-Plastic Composites Made with Different Lignocellulosic Materials that Vary in Their Morphology, Chemical Composition and Thermal Stability
by Ke-Chang Hung, Heng Yeh, Teng-Chun Yang, Tung-Lin Wu, Jin-Wei Xu and Jyh-Horng Wu *
Department of Forestry, National Chung Hsing University, Taichung 402, Taiwan
Polymers 2017, 9(12), 726; https://doi.org/10.3390/polym9120726 - 17 Dec 2017
Cited by 28 | Viewed by 7621
Abstract
In this study, four kinds of lignocellulosic fibers (LFs), namely, those from Chinese fir (Cunninghamia lanceolata), Taiwan red pine (Pinus taiwanensis), India-charcoal trema (Trema orientalis) and makino bamboo (Phyllostachys makinoi), were selected as reinforcements and incorporated into high-density polyethylene (HDPE) to manufacture wood-plastic [...] Read more.
In this study, four kinds of lignocellulosic fibers (LFs), namely, those from Chinese fir (Cunninghamia lanceolata), Taiwan red pine (Pinus taiwanensis), India-charcoal trema (Trema orientalis) and makino bamboo (Phyllostachys makinoi), were selected as reinforcements and incorporated into high-density polyethylene (HDPE) to manufacture wood-plastic composites (WPCs) by a flat platen pressing process. In addition to comparing the differences in the physico-mechanical properties of these composites, their chemical compositions were evaluated and their thermal decomposition kinetics were analyzed to investigate the effects of the lignocellulosic species on the properties of the WPCs. The results showed that the WPC made with Chinese fir displayed a typical M-shaped vertical density profile due to the high aspect ratio of its LFs, while a flat vertical density profile was observed for the WPCs made with other LFs. Thus, the WPC made with Chinese fir exhibited higher flexural properties and lower internal bond strength (IB) than other WPCs. In addition, the Taiwan red pine contained the lowest holocellulose content and the highest extractives and α-cellulose contents, which gave the resulting WPC lower water absorption and flexural properties. On the other hand, consistent with the flexural properties, the results of thermal decomposition kinetic analysis showed that the activation energy of the LFs at 10% of the conversion rate increased in the order of Taiwan red pine (146–161 kJ/mol), makino bamboo (158–175 kJ/mol), India-charcoal trema (185–194 kJ/mol) and Chinese fir (194–202 kJ/mol). These results indicate that the morphology, chemical composition and thermal stability of the LFs can have a substantial impact on the physico-mechanical properties of the resulting WPCs. Full article
(This article belongs to the Collection Polysaccharides)
Show Figures

Graphical abstract

28 pages, 10428 KiB  
Article
Preparation and Characterization of Breathable Hemostatic Hydrogel Dressings and Determination of Their Effects on Full-Thickness Defects
by Hong Pan 1,2, Daidi Fan 1,2,*, Wei Cao 1, Chenhui Zhu 1,2, Zhiguang Duan 1,2, Rongzhan Fu 1,2, Xian Li 1,2 and Xiaoxuan Ma 1,2
1 College of Chemistry & Materials Science, Northwest University, Taibai North Road 229, Xi’an 710069, Shaanxi, China
2 Shaanxi Key Laboratory of Degradable Biomedical Materials, Department of Chemical Engineering, Northwest University, Taibai North Road 229, Xi’an 710069, Shaanxi, China
Polymers 2017, 9(12), 727; https://doi.org/10.3390/polym9120727 - 18 Dec 2017
Cited by 59 | Viewed by 8786
Abstract
Hydrogel-based wound dressings provide a cooling sensation, a moist environment, and act as a barrier to microbes for wounds. In this study, a series of soft, flexible, porous non-stick hydrogel dressings were prepared through the simple repeated freeze-thawing of a poly(vinyl alcohol), human-like [...] Read more.
Hydrogel-based wound dressings provide a cooling sensation, a moist environment, and act as a barrier to microbes for wounds. In this study, a series of soft, flexible, porous non-stick hydrogel dressings were prepared through the simple repeated freeze-thawing of a poly(vinyl alcohol), human-like collagen (or and carboxymethyl chitosan) mixed solution rather than chemical cross-linking and Tween80 was added as pore-forming agent for cutaneous wound healing. Some of their physical and chemical properties were characterized. Interestingly, hydrogel PVA-HLC-T80 and PVA-HLC-CS-T80 presented excellent swelling ratios, bacterial barrier activity, moisture vapor permeability, hemostasis activity and biocompatibility. Furthermore, in vivo evaluation of the healing capacity of these two hydrogels was checked by creating a full-thickness wound defect (1.3 cm × 1.3 cm) in rabbit. Macroscopic observation and subsequent hematoxylin eosin staining (H&E) staining and transmission electron microscopy (TEM) analysis at regular time intervals for 18 days revealed that the hydrogels significantly enhanced wound healing by reducing inflammation, promoting granulation tissue formation, collagen deposition and accelerating re-epithelialization. Taken together, the obtained data strongly encourage the use of these multifunctional hydrogels for skin wound dressings. Full article
(This article belongs to the Special Issue Hydrogels in Tissue Engineering and Regenerative Medicine)
Show Figures

Figure 1

12 pages, 5468 KiB  
Article
The Effect of Carbon Nanotubes on the Mechanical Properties of Wood Plastic Composites by Selective Laser Sintering
by Yunhe Zhang 1,*, Jing Fang 1, Jian Li 1, Yanling Guo 1,* and Qingwen Wang 2
1 College of Mechanical and Electrical Engineering, Northeast Forestry University, Harbin 150040, China
2 College of Marterials and Energy, South China Agricultural University, Guangzhou 510642, China
Polymers 2017, 9(12), 728; https://doi.org/10.3390/polym9120728 - 18 Dec 2017
Cited by 32 | Viewed by 6275
Abstract
Wood-plastic composites (WPCs) made by selective laser sintering (SLS) approach of 3D printing offer many advantages over single polymer materials, such as low cost, sustainability, and better sintering accuracy. However, WPCs made via SLS are too weak to have widespread applications. In order [...] Read more.
Wood-plastic composites (WPCs) made by selective laser sintering (SLS) approach of 3D printing offer many advantages over single polymer materials, such as low cost, sustainability, and better sintering accuracy. However, WPCs made via SLS are too weak to have widespread applications. In order to increase the mechanical properties of WPCs, a novel type of WPCs containing 0, 0.05, 0.1 and 0.15 wt % carbon nanotubes (CNT), 14 wt % wood fibers, 86 wt % polyether sulfone (PES) was manufactured via SLS. The experimental results showed that the addition of small amount of CNTs can significantly increase the mechanical properties of the wood/PES composite material. The tensile strength, bending strength, and elasticity modulus were 76.3%, 227.9%, and 128.7% higher with 0.1 wt % CNTs than those without CNTs. The mechanical properties of specimens first increased and then decreased with the addition of CNTs. The SEM results of the specimens’ fracture morphology indicate that the preferable bonding interfaces between wood flour grains and PES grains were achieved by adding CNTs to the composites. There are two reasons why the composites possessed superior mechanical properties: CNTs facilitate the laser sintering process of WPCs due to their thermal conductivities, and CNTs directly reinforce WPCs. Full article
Show Figures

Graphical abstract

11 pages, 3310 KiB  
Article
Characterization of Chromatic Dispersion and Refractive Index of Polymer Optical Fibers
by Igor Ayesta 1,*, Joseba Zubia 2, Jon Arrue 2, María Asunción Illarramendi 3 and Mikel Azkune 2
1 Department of Applied Mathematics, Engineering School of Bilbao, University of the Basque Country (UPV/EHU), Plaza Ingeniero Torres Quevedo, 1, E-48013 Bilbao, Spain
2 Department of Communications Engineering, Engineering School of Bilbao, University of the Basque Country (UPV/EHU), Plaza Ingeniero Torres Quevedo, 1, E-48013 Bilbao, Spain
3 Department of Applied Physics I, University of the Basque Country (UPV/EHU), Engineering School of Bilbao, Plaza Ingeniero Torres Quevedo, 1, E-48013 Bilbao, Spain
Polymers 2017, 9(12), 730; https://doi.org/10.3390/polym9120730 - 20 Dec 2017
Cited by 17 | Viewed by 7384
Abstract
The chromatic dispersion and the refractive index of poly(methyl methacrylate) polymer optical fibers (POFs) have been characterized in this work by using a tunable femtosecond laser and a Streak Camera. The characterization technique is based on the measurement of the time delays of [...] Read more.
The chromatic dispersion and the refractive index of poly(methyl methacrylate) polymer optical fibers (POFs) have been characterized in this work by using a tunable femtosecond laser and a Streak Camera. The characterization technique is based on the measurement of the time delays of light pulses propagating along POFs at different wavelengths. Polymer fibers of three different lengths made by two manufacturers have been employed for that purpose, and discrepancies lower than 3% have been obtained in all cases. Full article
(This article belongs to the Special Issue Polymeric Materials for Optical Applications)
Show Figures

Graphical abstract

12 pages, 2479 KiB  
Article
Adhesives for Achieving Durable Bonds with Acetylated Wood
by Charles R. Frihart *, Rishawn Brandon, James F. Beecher and Rebecca E. Ibach
USDA Forest Service Forest Products Laboratory, Madison, WI 53726-2398, USA
Polymers 2017, 9(12), 731; https://doi.org/10.3390/polym9120731 - 20 Dec 2017
Cited by 23 | Viewed by 6333
Abstract
Acetylation of wood imparts moisture durability, decay resistance, and dimensional stability to wood; however, making durable adhesive bonds with acetylated wood can be more difficult than with unmodified wood. The usual explanation is that the acetylated surface has fewer hydroxyl groups, resulting in [...] Read more.
Acetylation of wood imparts moisture durability, decay resistance, and dimensional stability to wood; however, making durable adhesive bonds with acetylated wood can be more difficult than with unmodified wood. The usual explanation is that the acetylated surface has fewer hydroxyl groups, resulting in a harder-to-wet surface and in fewer hydrogen bonds between wood and adhesive. This concept was evaluated using four different adhesives (resorcinol–formaldehyde, emulsion polymer isocyanate, epoxy, and melamine–formaldehyde) with unmodified wood, acetylated wood, and acetylated wood that had been planed. Strikingly, acetylation did not hinder adhesive bonds with a waterborne resorcinol–formaldehyde adhesive that bonded equally well to both unmodified and acetylated yellow poplar. An epoxy adhesive bonded better to the acetylated wood than to the unmodified wood, in contrast to an emulsion polymer isocyanate, which gave less durable bonds to acetylated than to unmodified wood. Planing of the acetylated wood surface prior to bonding reduced bond durability for the epoxy adhesive and increased the amount of surface hydroxyl groups, as measured using X-ray photoelectron spectroscopic analysis of the trifluoroacetic anhydride-treated wood. These experiments showed that wood modification is useful in understanding wood-adhesive interactions, in addition to determining how to develop adhesives for acetylated woods. Full article
(This article belongs to the Collection Polymeric Adhesives)
Show Figures

Graphical abstract

18 pages, 4919 KiB  
Article
Morphological and Structural Analysis of Polyaniline and Poly(o-anisidine) Layers Generated in a DC Glow Discharge Plasma by Using an Oblique Angle Electrode Deposition Configuration
by Bogdan Butoi 1,2, Andreea Groza 2,*, Paul Dinca 1,2, Adriana Balan 3 and Valentin Barna 1,*
1 Faculty of Physics, University of Bucharest, 405 Atomistilor Street, 077125 Magurele, Romania
2 National Institute for Laser, Plasma and Radiation Physics, 409 Atomistilor Street, 077125 Magurele, Romania
3 Nano-SAE Research Centre, Faculty of Physics, University of Bucharest, 077125 Magurele, Romania
Polymers 2017, 9(12), 732; https://doi.org/10.3390/polym9120732 - 20 Dec 2017
Cited by 166 | Viewed by 9650
Abstract
This work is focused on the structural and morphological investigations of polyaniline and poly(o-anisidine) polymers generated in a direct current glow discharge plasma, in the vapors of the monomers, without a buffer gas, using an oblique angle-positioned substrate configuration. By atomic [...] Read more.
This work is focused on the structural and morphological investigations of polyaniline and poly(o-anisidine) polymers generated in a direct current glow discharge plasma, in the vapors of the monomers, without a buffer gas, using an oblique angle-positioned substrate configuration. By atomic force microscopy and scanning electron microscopy we identified the formation of worm-like interlinked structures on the surface of the polyaniline layers, the layers being compact in the bulk. The poly(o-anisidine) layers are flat with no kind of structures on their surfaces. By Fourier transform infrared spectroscopy we identified the main IR bands characteristic of polyaniline and poly(o-anisidine), confirming that the polyaniline chemical structure is in the emeraldine form. The IR band from 1070 cm−1 was attributed to the emeraldine salt form of polyaniline as an indication of its doping with H+. The appearance of the IR band at 1155 cm−1 also indicates the conducting protonated of polyaniline. The X-ray diffraction revealed the formation of crystalline domains embedded in an amorphous matrix within the polyaniline layers. The interchain separation length of 3.59 Å is also an indicator of the conductive character of the polymers. The X-ray diffraction pattern of poly(o-anisidine) highlights the semi-crystalline nature of the layers. The electrical conductivities of polyaniline and poly(o-anisidine) layers and their dependence with temperature are also investigated. Full article
(This article belongs to the Special Issue Conductive Polymers 2017)
Show Figures

Graphical abstract

11 pages, 1537 KiB  
Article
Microencapsulation of Lactobacillus Acidophilus by Xanthan-Chitosan and Its Stability in Yoghurt
by Guowei Shu 1,*, Yunxia He 1, Li Chen 2,*, Yajuan Song 1, Jiangpeng Meng 3 and He Chen 1
1 School of Food and Biological Engineering, Shaanxi University of Science and Technology, Xi’an 710021, China
2 College of Food Engineering and Nutritional Science, Shaanxi Normal University, Xi’an 710119, China
3 Xi’an Baiyue Goat Milk Corp., Ltd., Xi’an 710089, China
Polymers 2017, 9(12), 733; https://doi.org/10.3390/polym9120733 - 20 Dec 2017
Cited by 22 | Viewed by 6941
Abstract
Microencapsulations of Lactobacillus acidophilus in xanthan-chitosan (XC) and xanthan-chitosan-xanthan (XCX) polyelectrolyte complex (PEC) gels were prepared in this study. The process of encapsulation was optimized with the aid of response surface methodology (RSM). The optimum condition was chitosan of 0.68%, xanthan of 0.76%, [...] Read more.
Microencapsulations of Lactobacillus acidophilus in xanthan-chitosan (XC) and xanthan-chitosan-xanthan (XCX) polyelectrolyte complex (PEC) gels were prepared in this study. The process of encapsulation was optimized with the aid of response surface methodology (RSM). The optimum condition was chitosan of 0.68%, xanthan of 0.76%, xanthan-L. acidophilus mixture (XLM)/chitosan of 1:2.56 corresponding to a high viable count (1.31 ± 0.14) × 1010 CFU·g−1, and encapsulation yield 86 ± 0.99%, respectively. Additionally, the application of a new encapsulation system (XC and XCX) in yoghurt achieved great success in bacterial survival during the storage of 21 d at 4 °C and 25 °C, respectively. Specially, pH and acidity in yogurt were significantly influenced by the new encapsulation system in comparison to free suspension during 21 d storage. Our study provided a potential encapsulation system for probiotic application in dairy product which paving a new way for functional food development. Full article
(This article belongs to the Special Issue Polysaccharides)
Show Figures

Graphical abstract

10 pages, 2946 KiB  
Article
Preparation and Evaluation of a Polyimide-Coated Ultrafine Gilt Molybdenum Wire and Its Knitted Mesh Used for Electromagnetic Reflectors
by Huiqi Shao 1,2, Nanliang Chen 1,2, Shuang Li 1,3, Fangbing Lin 1,2, Jinhua Jiang 1,2,* and Xiaofei Ma 4
1 State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, Shanghai 201620, China
2 College of Textiles, Donghua University, Shanghai 201620, China
3 Key Laboratory of High Performance fibers & products, Ministry of Education, Donghua University, Shanghai 201620, China
4 Xi’an Institute of Space Radio Technology; Xi’an 710100, China
Polymers 2017, 9(12), 734; https://doi.org/10.3390/polym9120734 - 20 Dec 2017
Cited by 10 | Viewed by 6930
Abstract
In this work, polyimide (PI) was coated onto an ultrafine gilt molybdenum wire in order to protect the gilt surface and prepare an electrically stable wire mesh material which can be widely used in space. The surface of the PI-coated gilt molybdenum wires [...] Read more.
In this work, polyimide (PI) was coated onto an ultrafine gilt molybdenum wire in order to protect the gilt surface and prepare an electrically stable wire mesh material which can be widely used in space. The surface of the PI-coated gilt molybdenum wires was characterized using FTIR, SEM, and EDS. Factors such as temperature stability of the PI coating, mechanical properties of the PI-coated gilt molybdenum wires, contact resistance stability, and electromagnetic microwave reflectivity of the their knitted meshes were also investigated. The results indicate that the PI coating conformed uniformly to the surface of the gilt molybdenum wires. The prepared PI coating exhibited excellent temperature stability in the −196 to 300 °C range and could efficiently protect the gilt surface and improve the stability of contact resistance, while the reflection of its wire meshes showed only a slight decrease of 1.4% with the PI coating thickness of 3 μm for electromagnetic microwaves in the S band. Full article
(This article belongs to the Special Issue Textile and Textile-Based Materials)
Show Figures

Graphical abstract

17 pages, 16840 KiB  
Article
Layer-by-Layer Assembly of Polyelectrolyte Multilayer onto PET Fabric for Highly Tunable Dyeing with Water Soluble Dyestuffs
by Shili Xiao 1,*, Pengjun Xu 2, Qingyan Peng 1, Jiali Chen 1, Jiankang Huang 1, Faming Wang 3,* and Nuruzzaman Noor 3
1 Key Laboratory of Green Processing and Functional Textiles of New Textile Materials, Ministry of Education, Wuhan Textile University, Wuhan 430073, China
2 Faculty of Clothing and Design, Minjiang University, Fuzhou 350108, Fujian, China
3 Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
Polymers 2017, 9(12), 735; https://doi.org/10.3390/polym9120735 - 20 Dec 2017
Cited by 98 | Viewed by 8417
Abstract
Poly(ethyleneterephthalate) (PET) is a multi-purpose and widely used synthetic polymer in many industrial fields because of its remarkable advantages such as low cost, light weight, high toughness and resistance to chemicals, and high abrasion resistance. However, PET suffers from poor dyeability due to [...] Read more.
Poly(ethyleneterephthalate) (PET) is a multi-purpose and widely used synthetic polymer in many industrial fields because of its remarkable advantages such as low cost, light weight, high toughness and resistance to chemicals, and high abrasion resistance. However, PET suffers from poor dyeability due to its non-polar nature, benzene ring structure as well as high crystallinity. In this study, PET fabrics were firstly treated with an alkaline solution to produce carboxylic acid functional groups on the surface of the PET fabric, and then was modified by polyelectrolyte polymer through the electrostatic layer-by-layer self-assembly technology. The polyelectrolyte multilayer-deposited PET fabric was characterized using scanning electron microscopy SEM, contact angle, Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS). The dyeability of PET fabrics before and after surface modification was systematically investigated. It showed that the dye-uptake of the polyelectrolyte multilayer-deposited PET fabric has been enhanced compared to that of the pristine PET fabric. In addition, its dyeability is strongly dependent on the surface property of the polyelectrolyte multilayer-deposited PET fabric and the properties of dyestuffs. Full article
(This article belongs to the Special Issue Textile and Textile-Based Materials)
Show Figures

Graphical abstract

14 pages, 6700 KiB  
Article
Immobilization of Platelet-Rich Plasma onto COOH Plasma-Coated PCL Nanofibers Boost Viability and Proliferation of Human Mesenchymal Stem Cells
by Anastasiya Solovieva 1,2, Svetlana Miroshnichenko 1,3, Andrey Kovalskii 2, Elizaveta Permyakova 2, Zakhar Popov 2, Eva Dvořáková 4, Philip Kiryukhantsev-Korneev 2, Aleksei Obrosov 5, Josef Polčak 6,7, Lenka Zajíčková 4, Dmitry V. Shtansky 2 and Anton Manakhov 2,*
1 Scientific Institute of Clinical and Experimental Lymphology-Branch of the ICG SB RAS, 2 Timakova str., 630060 Novosibirsk, Russia
2 National University of Science and Technology “MISiS”, Leninsky pr. 4, 119049 Moscow, Russia
3 Research Institute of Biochemistry, 2 Timakova str., 630117 Novosibirsk, Russia
4 RG Plasma Technologies, CEITEC–Central European Institute of Technology, Masaryk University, Purkyňova 123, 61200 Brno, Czech Republic
5 Chair of Physical Metallurgy and Materials Technology, Brandenburg Technical University, 03046 Cottbus, Germany
6 CEITEC-Central European Institute of Technology, Brno University of Technology, Technická 3058/10, 61600 Brno, Czech Republic
7 Institute of Physical Engineering, Brno University of Technology, Technicka 2896/2, 616 69 Brno, Czech Republic
Polymers 2017, 9(12), 736; https://doi.org/10.3390/polym9120736 - 20 Dec 2017
Cited by 35 | Viewed by 8369
Abstract
The scaffolds made of polycaprolactone (PCL) are actively employed in different areas of biology and medicine, especially in tissue engineering. However, the usage of unmodified PCL is significantly restricted by the hydrophobicity of its surface, due to the fact that its inert surface [...] Read more.
The scaffolds made of polycaprolactone (PCL) are actively employed in different areas of biology and medicine, especially in tissue engineering. However, the usage of unmodified PCL is significantly restricted by the hydrophobicity of its surface, due to the fact that its inert surface hinders the adhesion of cells and the cell interactions on PCL surface. In this work, the surface of PCL nanofibers is modified by Ar/CO2/C2H4 plasma depositing active COOH groups in the amount of 0.57 at % that were later used for the immobilization of platelet-rich plasma (PRP). The modification of PCL nanofibers significantly enhances the viability and proliferation (by hundred times) of human mesenchymal stem cells, and decreases apoptotic cell death to a normal level. According to X-ray photoelectron spectroscopy (XPS), after immobilization of PRP, up to 10.7 at % of nitrogen was incorporated into the nanofibers surface confirming the grafting of proteins. Active proliferation and sustaining the cell viability on nanofibers with immobilized PRP led to an average number of cells of 258 ± 12.9 and 364 ± 34.5 for nanofibers with ionic and covalent bonding of PRP, respectively. Hence, our new method for the modification of PCL nanofibers with PRP opens new possibilities for its application in tissue engineering. Full article
(This article belongs to the Special Issue Surface Modification and Functional Coatings for Polymers)
Show Figures

Graphical abstract

Review

Jump to: Editorial, Research, Other

27 pages, 2789 KiB  
Review
Recent Advances in Antimicrobial Hydrogels Containing Metal Ions and Metals/Metal Oxide Nanoparticles
by Fazli Wahid 1, Cheng Zhong 1, Hai-Song Wang 2, Xiao-Hui Hu 1 and Li-Qiang Chu 2,*
1 Key Laboratory of Industrial Fermentation Microbiology (Ministry of Education), Tianjin University of Science and Technology, No. 29, 13th Avenue, TEDA, Tianjin 300457, China
2 College of Chemical Engineering and Materials Science, Tianjin University of Science and Technology, No. 29, 13th Avenue, TEDA, Tianjin 300457, China
Polymers 2017, 9(12), 636; https://doi.org/10.3390/polym9120636 - 23 Nov 2017
Cited by 179 | Viewed by 14625
Abstract
Recently, the rapid emergence of antibiotic-resistant pathogens has caused a serious health problem. Scientists respond to the threat by developing new antimicrobial materials to prevent or control infections caused by these pathogens. Polymer-based nanocomposite hydrogels are versatile materials as an alternative to conventional [...] Read more.
Recently, the rapid emergence of antibiotic-resistant pathogens has caused a serious health problem. Scientists respond to the threat by developing new antimicrobial materials to prevent or control infections caused by these pathogens. Polymer-based nanocomposite hydrogels are versatile materials as an alternative to conventional antimicrobial agents. Cross-linking of polymeric materials by metal ions or the combination of polymeric hydrogels with nanoparticles (metals and metal oxide) is a simple and effective approach for obtaining a multicomponent system with diverse functionalities. Several metals and metal oxides such as silver (Ag), gold (Au), zinc oxide (ZnO), copper oxide (CuO), titanium dioxide (TiO2) and magnesium oxide (MgO) have been loaded into hydrogels for antimicrobial applications. The incorporation of metals and metal oxide nanoparticles into hydrogels not only enhances the antimicrobial activity of hydrogels, but also improve their mechanical characteristics. Herein, we summarize recent advances in hydrogels containing metal ions, metals and metal oxide nanoparticles with potential antimicrobial properties. Full article
(This article belongs to the Special Issue Hydrogels in Tissue Engineering and Regenerative Medicine)
Show Figures

Graphical abstract

18 pages, 5890 KiB  
Review
Dormant Polymers and Their Role in Living and Controlled Polymerizations; Influence on Polymer Chemistry, Particularly on the Ring Opening Polymerization
by Stanislaw Penczek *, Julia Pretula and Piotr Lewiński
Centre of Molecular and Macromolecular Studies of Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz, Poland
Polymers 2017, 9(12), 646; https://doi.org/10.3390/polym9120646 - 25 Nov 2017
Cited by 12 | Viewed by 6896
Abstract
Living polymerization discovered by Professor Szwarc is known well to all chemists. Some of the living polymerizations involve dormancy, a process in which there is an equilibrium (or at least exchange) between two types of living polymers, namely active at the given moment [...] Read more.
Living polymerization discovered by Professor Szwarc is known well to all chemists. Some of the living polymerizations involve dormancy, a process in which there is an equilibrium (or at least exchange) between two types of living polymers, namely active at the given moment and dormant at this moment and becoming active in the process of activation. These processes are at least equally important although less known. This mini review is devoted to these particular living polymerizations, mostly polymerizations by the Ring-Opening Polymerization mechanisms (ROP) compared with some selected close to living vinyl polymerizations (the most spectacular is Atom Transfer Radical Polymerization (ATRP)) involving dormancy. Cationic polymerization of tetrahydrofuran was the first one, based on equilibrium between oxonium ions (active) and covalent (esters) dormant species, i.e., temporarily inactive, and is described in detail. The other systems discussed are polymerization of oxazolines and cyclic esters as well as controlled radical and cationic polymerizations of vinyl monomers. Full article
(This article belongs to the Special Issue Living Polymerization)
Show Figures

Figure 1

22 pages, 4115 KiB  
Review
Microporous Hyper-Crosslinked Polystyrenes and Nanocomposites with High Adsorption Properties: A Review
by Rachele Castaldo 1,*, Gennaro Gentile 1, Maurizio Avella 1, Cosimo Carfagna 1 and Veronica Ambrogi 2
1 Institute for Polymers, Composites and Biomaterials, National Research Council of Italy, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
2 Department of Chemical, Materials and Production Engineering, University of Naples, Piazzale Tecchio 80, 80125 Napoli, Italy
Polymers 2017, 9(12), 651; https://doi.org/10.3390/polym9120651 - 28 Nov 2017
Cited by 87 | Viewed by 12563
Abstract
Hyper-crosslinked (HCL) polystyrenes show outstanding properties, such as high specific surface area and adsorption capability. Several researches have been recently focused on tailoring their performance for specific applications, such as gas adsorption and separation, energy storage, air and water purification processes, and catalysis. [...] Read more.
Hyper-crosslinked (HCL) polystyrenes show outstanding properties, such as high specific surface area and adsorption capability. Several researches have been recently focused on tailoring their performance for specific applications, such as gas adsorption and separation, energy storage, air and water purification processes, and catalysis. In this review, main strategies for the realization of HCL polystyrene-based materials with advanced properties are reported, including a summary of the synthetic routes that are adopted for their realization and the chemical modification approaches that are used to impart them specific functionalities. Moreover, the most up to date results on the synthesis of HCL polystyrene-based nanocomposites that are realized by embedding these high surface area polymers with metal, metal oxide, and carbon-based nanofillers are discussed in detail, underlining the high potential applicability of these systems in different fields. Full article
(This article belongs to the Special Issue Polymer Nanocomposites)
Show Figures

Graphical abstract

24 pages, 14489 KiB  
Review
Nucleobase-Containing Polymers: Structure, Synthesis, and Applications
by Haitao Yang 1 and Weixian Xi 2,3,*
1 School of Materials Science and Engineering, Nanchang Hangkong University, Nanchang 330063, China
2 Department of Chemical and Biomolecular Engineering, University of California Los Angeles, Los Angeles, CA 90095, USA
3 Department of Orthopedic Surgery, University of California Los Angeles, Los Angeles, CA 90095, USA
Polymers 2017, 9(12), 666; https://doi.org/10.3390/polym9120666 - 1 Dec 2017
Cited by 36 | Viewed by 10884
Abstract
Nucleobase interactions play a fundamental role in biological functions, including transcription and translation. Natural nucleic acids like DNA are also widely implemented in material realm such as DNA guided self-assembly of nanomaterials. Inspired by that, polymer chemists have contributed phenomenal endeavors to mimic [...] Read more.
Nucleobase interactions play a fundamental role in biological functions, including transcription and translation. Natural nucleic acids like DNA are also widely implemented in material realm such as DNA guided self-assembly of nanomaterials. Inspired by that, polymer chemists have contributed phenomenal endeavors to mimic both the structures and functions of natural nucleic acids in synthetic polymers. Similar sequence-dependent responses were observed and employed in the self-assembly of these nucleobase-containing polymers. Here, the structures, synthetic approaches, and applications of nucleobase-containing polymers are highlighted and a brief look is taken at the future development of these polymers. Full article
(This article belongs to the Special Issue Polymers and Block Copolymers at Interfaces and Surfaces)
Show Figures

Graphical abstract

32 pages, 3899 KiB  
Review
Hydrogels for Cartilage Regeneration, from Polysaccharides to Hybrids
by Daniela Anahí Sánchez-Téllez 1,2,*, Lucía Téllez-Jurado 1 and Luís María Rodríguez-Lorenzo 2,3
1 Instituto Politécnico Nacional-ESIQIE, Depto. Ing. en Metalurgia y Materiales, UPALM-Zacatenco, Mexico City 07738, Mexico
2 Networking Biomedical Research Centre in Bioengineering, Biomaterials and Nanomedicine, Centro de Investigación Biomédica en Red—Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Av. Monforte de Lemos 3-5, Pabellón 11, Planta 0, 28029 Madrid, Spain
3 Department Polymeric Nanomaterials and Biomaterials, ICTP-CSIC, Juan de la Cierva 3, 28006 Madrid, Spain
Polymers 2017, 9(12), 671; https://doi.org/10.3390/polym9120671 - 4 Dec 2017
Cited by 76 | Viewed by 13017
Abstract
The aims of this paper are: (1) to review the current state of the art in the field of cartilage substitution and regeneration; (2) to examine the patented biomaterials being used in preclinical and clinical stages; (3) to explore the potential of polymeric [...] Read more.
The aims of this paper are: (1) to review the current state of the art in the field of cartilage substitution and regeneration; (2) to examine the patented biomaterials being used in preclinical and clinical stages; (3) to explore the potential of polymeric hydrogels for these applications and the reasons that hinder their clinical success. The studies about hydrogels used as potential biomaterials selected for this review are divided into the two major trends in tissue engineering: (1) the use of cell-free biomaterials; and (2) the use of cell seeded biomaterials. Preparation techniques and resulting hydrogel properties are also reviewed. More recent proposals, based on the combination of different polymers and the hybridization process to improve the properties of these materials, are also reviewed. The combination of elements such as scaffolds (cellular solids), matrices (hydrogel-based), growth factors and mechanical stimuli is needed to optimize properties of the required materials in order to facilitate tissue formation, cartilage regeneration and final clinical application. Polymer combinations and hybrids are the most promising materials for this application. Hybrid scaffolds may maximize cell growth and local tissue integration by forming cartilage-like tissue with biomimetic features. Full article
(This article belongs to the Collection Polysaccharides)
Show Figures

Graphical abstract

19 pages, 6151 KiB  
Review
Reorganizing Polymer Chains with Cyclodextrins
by Alper Gurarslan, Abhay Joijode, Jialong Shen, Ganesh Narayanan, Gerry J. Antony, Shanshan Li, Yavuz Caydamli and Alan E. Tonelli *
Fiber & Polymer Science Program, College of Textiles, North Carolina State University, Raleigh, NC 27606-8301, USA
Polymers 2017, 9(12), 673; https://doi.org/10.3390/polym9120673 - 4 Dec 2017
Cited by 11 | Viewed by 5787
Abstract
During the past several years, we have been utilizing cyclodextrins (CDs) to nanostructure polymers into bulk samples whose chain organizations, properties, and behaviors are quite distinct from neat bulk samples obtained from their solutions and melts. We first form non-covalently bonded inclusion complexes [...] Read more.
During the past several years, we have been utilizing cyclodextrins (CDs) to nanostructure polymers into bulk samples whose chain organizations, properties, and behaviors are quite distinct from neat bulk samples obtained from their solutions and melts. We first form non-covalently bonded inclusion complexes (ICs) between CD hosts and guest polymers, where the guest chains are highly extended and separately occupy the narrow channels (~0.5–1.0 nm in diameter) formed by the columnar arrangement of CDs in the IC crystals. Careful removal of the host crystalline CD lattice from the polymer-CD-IC crystals leads to coalescence of the guest polymer chains into bulk samples, which we have repeatedly observed to behave distinctly from those produced from their solutions or melts. While amorphous polymers coalesced from their CD-ICs evidence significantly higher glass-transition temperatures, Tgs, polymers that crystallize generally show higher melting and crystallization temperatures (Tms, Tcs), and some-times different crystalline polymorphs, when they are coalesced from their CD-ICs. Formation of CD-ICs containing two or more guest homopolymers or with block copolymers can result in coalesced samples which exhibit intimate mixing between their common homopolymer chains or between the blocks of the copolymer. On a more practically relevant level, the distinct organizations and behaviors observed for polymer samples coalesced from their CD-ICs are found to be stable to extended annealing at temperatures above their Tgs and Tms. We believe this is a consequence of the structural organization of the crystalline polymer-CD-ICs, where the guest polymer chains included in host-IC crystals are separated and confined to occupy the narrow channels formed by the host CDs during IC crystallization. Substantial degrees of the extended and un-entangled natures of the IC-included chains are apparently retained upon coalescence, and are resistant to high temperature annealing. Following the careful removal of the host CD lattice from each randomly oriented IC crystal, the guest polymer chains now occupying a much-reduced volume may be somewhat “nematically” oriented, resulting in a collection of randomly oriented “nematic” regions of largely extended and un-entangled coalesced guest chains. The suggested randomly oriented nematic domain organization of guest polymers might explain why even at high temperatures their transformation to randomly-coiling, interpenetrated, and entangled melts might be difficult. In addition, the behaviors and uses of polymers coalesced from their CD-ICs are briefly described and summarized here, and we attempted to draw conclusions from and relationships between their behaviors and the unique chain organizations and conformations achieved upon coalescence. Full article
(This article belongs to the Special Issue Host-Guest Polymer Complexes)
Show Figures

Figure 1

33 pages, 25513 KiB  
Review
Preparation, Characterization and Application of Polysaccharide-Based Metallic Nanoparticles: A Review
by Cong Wang, Xudong Gao, Zhongqin Chen, Yue Chen and Haixia Chen *
Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin 300072, China
Polymers 2017, 9(12), 689; https://doi.org/10.3390/polym9120689 - 8 Dec 2017
Cited by 154 | Viewed by 13625
Abstract
Polysaccharides are natural biopolymers that have been recognized to be the most promising hosts for the synthesis of metallic nanoparticles (MNPs) because of their outstanding biocompatible and biodegradable properties. Polysaccharides are diverse in size and molecular chains, making them suitable for the reduction [...] Read more.
Polysaccharides are natural biopolymers that have been recognized to be the most promising hosts for the synthesis of metallic nanoparticles (MNPs) because of their outstanding biocompatible and biodegradable properties. Polysaccharides are diverse in size and molecular chains, making them suitable for the reduction and stabilization of MNPs. Considerable research has been directed toward investigating polysaccharide-based metallic nanoparticles (PMNPs) through host–guest strategy. In this review, approaches of preparation, including top-down and bottom-up approaches, are presented and compared. Different characterization techniques such as scanning electron microscopy, transmission electron microscopy, dynamic light scattering, UV-visible spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction and small-angle X-ray scattering are discussed in detail. Besides, the applications of PMNPs in the field of wound healing, targeted delivery, biosensing, catalysis and agents with antimicrobial, antiviral and anticancer capabilities are specifically highlighted. The controversial toxicological effects of PMNPs are also discussed. This review can provide significant insights into the utilization of polysaccharides as the hosts to synthesize MPNs and facilitate their further development in synthesis approaches, characterization techniques as well as potential applications. Full article
(This article belongs to the Collection Polysaccharides)
Show Figures

Graphical abstract

49 pages, 14425 KiB  
Review
Recent Advances in the Fabrication of Membranes Containing “Ion Pairs” for Nanofiltration Processes
by Yan-Li Ji 1, Bing-Xin Gu 1, Quan-Fu An 2,* and Cong-Jie Gao 1
1 Center for Membrane and Water Science & Technology, Ocean College, Zhejiang University of Technology, Hangzhou 310014, China
2 Beijing Key Laboratory for Green Catalysis and Separation, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124, China
Polymers 2017, 9(12), 715; https://doi.org/10.3390/polym9120715 - 14 Dec 2017
Cited by 51 | Viewed by 11314
Abstract
In the face of serious environmental pollution and water scarcity problems, the membrane separation technique, especially high efficiency, low energy consumption, and environmental friendly nanofiltration, has been quickly developed. Separation membranes with high permeability, good selectivity, and strong antifouling properties are critical for [...] Read more.
In the face of serious environmental pollution and water scarcity problems, the membrane separation technique, especially high efficiency, low energy consumption, and environmental friendly nanofiltration, has been quickly developed. Separation membranes with high permeability, good selectivity, and strong antifouling properties are critical for water treatment and green chemical processing. In recent years, researchers have paid more and more attention to the development of high performance nanofiltration membranes containing “ion pairs”. In this review, the effects of “ion pairs” characteristics, such as the super-hydrophilicity, controllable charge character, and antifouling property, on nanofiltration performances are discussed. A systematic survey was carried out on the various approaches and multiple regulation factors in the fabrication of polyelectrolyte complex membranes, zwitterionic membranes, and charged mosaic membranes, respectively. The mass transport behavior and antifouling mechanism of the membranes with “ion pairs” are also discussed. Finally, we present a brief perspective on the future development of advanced nanofiltration membranes with “ion pairs”. Full article
(This article belongs to the Special Issue Polymeric Membranes)
Show Figures

Figure 1

12 pages, 667 KiB  
Review
Exploiting Microbial Polysaccharides for Biosorption of Trace Elements in Aqueous Environments—Scope for Expansion via Nanomaterial Intervention
by Manikandan Muthu 1,†, Hui-Fen Wu 2,†, Judy Gopal 1, Iyyakkannu Sivanesan 3 and Sechul Chun 1,*
1 Department of Environmental Health Science, Konkuk University, Seoul 143-701, Korea
2 Department of Chemistry, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan
3 Department of Bioresources and Food Science, Konkuk University, 1, Hwayang-dong, Gwangjin-gu, Seoul 143-701, Korea
Co-first authors, both authors contribute equally.
Polymers 2017, 9(12), 721; https://doi.org/10.3390/polym9120721 - 16 Dec 2017
Cited by 35 | Viewed by 7635
Abstract
With pollution sounding high alarms all around us, there is an immediate necessity for remediation. In most cases, the remediation measures require further remediation—the anti-pollutants themselves cause pollution. In this correspondence, the search deepens towards natural biogenic components that can be used for [...] Read more.
With pollution sounding high alarms all around us, there is an immediate necessity for remediation. In most cases, the remediation measures require further remediation—the anti-pollutants themselves cause pollution. In this correspondence, the search deepens towards natural biogenic components that can be used for bioremediation. Polysaccharide and biosorption have been themes in discussion for quite some time, where a slow decline in the enthusiasm in this area has been observed. This review revisits the importance of using polysaccharide based materials for biosorption. The need for polysaccharide-based nanocomposites, which hold better promise for greater deliverables, is emphasized as a means of rejuvenating the future perspectives in this area of application. Full article
(This article belongs to the Special Issue Polysaccharides)
Show Figures

Graphical abstract

33 pages, 6668 KiB  
Review
Bio-Inspired Polymeric Structures with Special Wettability and Their Applications: An Overview
by Zihe Pan 1,2,3,4,*, Fangqin Cheng 1,2 and Boxin Zhao 3,4,*
1 Institute of Resources and Environmental Engineering, Shanxi University, 92 Wucheng Road, Xiaodian District, Taiyuan 030006, Shanxi, China
2 Shanxi Collaborative Innovation Center of High Value-Added Utilization of Coal-Related Wastes, Taiyuan 030006, Shanxi, China
3 Department of Chemical Engineering, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada
4 Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada
Polymers 2017, 9(12), 725; https://doi.org/10.3390/polym9120725 - 17 Dec 2017
Cited by 53 | Viewed by 16279
Abstract
It is not unusual for humans to be inspired by natural phenomena to develop new advanced materials; such materials are called bio-inspired materials. Interest in bio-inspired polymeric superhydrophilic, superhydrophobic, and superoleophobic materials has substantially increased over the last few decades, as has improvement [...] Read more.
It is not unusual for humans to be inspired by natural phenomena to develop new advanced materials; such materials are called bio-inspired materials. Interest in bio-inspired polymeric superhydrophilic, superhydrophobic, and superoleophobic materials has substantially increased over the last few decades, as has improvement in the related technologies. This review reports the latest developments in bio-inspired polymeric structures with desired wettability that have occurred by mimicking the structures of lotus leaf, rose petals, and the wings and shells of various creatures. The intrinsic role of surface chemistry and structure on delivering superhydrophilicity, superhydrophobicity, and superoleophobicity has been extensively explored. Typical polymers, commonly used structures, and techniques involved in developing bio-inspired surfaces with desired wettability are discussed. Additionally, the latest applications of bio-inspired structures with desired wettability in human activities are also introduced. Full article
(This article belongs to the Collection Polymeric Adhesives)
Show Figures

Graphical abstract

11 pages, 3698 KiB  
Review
Preparation and Material Application of Amylose-Polymer Inclusion Complexes by Enzymatic Polymerization Approach
by Saya Orio, Kazuya Yamamoto and Jun-ichi Kadokawa *
Department of Chemistry, Biotechnology, and Chemical Engineering, Graduate School of Science and Engineering, Kagoshima University, 1-21-40 Korimoto, Kagoshima 860-0065, Japan
Polymers 2017, 9(12), 729; https://doi.org/10.3390/polym9120729 - 18 Dec 2017
Cited by 19 | Viewed by 7488
Abstract
This review presents our researches on the preparation and material application of inclusion complexes that comprises an amylose host and polymeric guests through phosphorylase-catalyzed enzymatic polymerization. Amylose is a well-known polysaccharide and forms inclusion complexes with various hydrophobic small molecules. Pure amylose is [...] Read more.
This review presents our researches on the preparation and material application of inclusion complexes that comprises an amylose host and polymeric guests through phosphorylase-catalyzed enzymatic polymerization. Amylose is a well-known polysaccharide and forms inclusion complexes with various hydrophobic small molecules. Pure amylose is produced by enzymatic polymerization by using α-d-glucose 1-phosphate as a monomer and maltooligosaccharide as a primer catalyzed by phosphorylase. We determined that a propagating chain of amylose during enzymatic polymerization wraps around hydrophobic polymers present in the reaction system to form inclusion complexes. We termed this polymerization “vine-twining polymerization” because it is similar to the way vines of a plant grow around a rod. Hierarchical structured amylosic materials, such as hydrogels and films, were fabricated by inclusion complexation through vine-twining polymerization by using copolymers covalently grafted with hydrophobic guest polymers. The enzymatically produced amyloses induced complexation with the guest polymers in the intermolecular graft copolymers, which acted as cross-linking points to form supramolecular hydrogels. By including a film-formable main-chain in the graft copolymer, a supramolecular film was obtained through hydrogelation. Supramolecular polymeric materials were successfully fabricated through vine-twining polymerization by using primer-guest conjugates. The products of vine-twining polymerization form polymeric continuums of inclusion complexes, where the enzymatically produced amylose chains elongate from the conjugates included in the guest segments of the other conjugates. Full article
(This article belongs to the Special Issue Host-Guest Polymer Complexes)
Show Figures

Figure 1

Other

2 pages, 376 KiB  
Correction
Correction: Benková, Z.; et al. Structural Behavior of a Semiflexible Polymer Chain in an Array of Nanoposts Polymers 2017, 9, 313
by Zuzana Benková 1,2,*, Lucia Rišpanová 1 and Peter Cifra 1
1 Polymer Institute, Slovak Academy of Sciences, Dúbravská Cesta 9, 845 41 Bratislava, Slovakia
2 LAQV@REQUIMTE, Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Rua do Campo Alegre 687, 4168-007 Porto, Portugal
Polymers 2017, 9(12), 665; https://doi.org/10.3390/polym9120665 - 1 Dec 2017
Viewed by 3238
Abstract
There was a mistake in the original code evaluating the occupation number of polymers [...] Full article
Show Figures

Figure 3

Previous Issue
Next Issue
Back to TopTop