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Polymers, Volume 10, Issue 10 (October 2018)

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Open AccessArticle Effects of Hydrothermal Pretreatment on the Structural Characteristics of Organosolv Lignin from Triarrhena lutarioriparia
Polymers 2018, 10(10), 1157; https://doi.org/10.3390/polym10101157 (registering DOI)
Received: 28 August 2018 / Revised: 26 September 2018 / Accepted: 14 October 2018 / Published: 16 October 2018
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Abstract
The effects of hydrothermal pretreatment (170–180 °C, 30–60 min) on the structural characteristics of enzymatic and extracted lignin from Triarrhena lutarioriparia (TL) during the integrated delignification process have been comprehensively investigated. Ion chromatography and NMR characterization showed that liquid products after
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The effects of hydrothermal pretreatment (170–180 °C, 30–60 min) on the structural characteristics of enzymatic and extracted lignin from Triarrhena lutarioriparia (TL) during the integrated delignification process have been comprehensively investigated. Ion chromatography and NMR characterization showed that liquid products after mild hydrothermal process (170 °C, 30 min) were mainly composed of xylooligosaccharide (XOS) with different degrees of polymerization (DP ≥ 2). In addition, the structural changes of lignin during hydrothermal pretreatment and organic acid delignification process have been demonstrated by quantitative 2D heteronuclear single quantum coherence (2D-HSQC) and 31P-NMR techniques. Results showed that the structural changes of lignin (e.g., cleavage of β-O-4 linkages) induced by the hydrothermal pretreatment will facilitate the subsequent organic acid delignification process, and acetylated lignin could be obtained with a considerable yield, which can be used in lignin-based composite and candidate feedstock for catalytic upgrading of lignin. In short, the proposed process facilitates the producing of XOS and acetylated lignin for lignin valorization. Full article
(This article belongs to the Special Issue Lignin Polymers: Structures, Reactions and Applications)
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Open AccessArticle Slip Spring-Based Mesoscopic Simulations of Polymer Networks: Methodology and the Corresponding Computational Code
Polymers 2018, 10(10), 1156; https://doi.org/10.3390/polym10101156 (registering DOI)
Received: 11 September 2018 / Revised: 10 October 2018 / Accepted: 12 October 2018 / Published: 16 October 2018
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Abstract
In previous work by the authors, a new methodology was developed for Brownian dynamics/kinetic Monte Carlo (BD/kMC) simulations of polymer melts. In this study, this methodology is extended for dynamical simulations of crosslinked polymer networks in a coarse-grained representation, wherein chains are modeled
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In previous work by the authors, a new methodology was developed for Brownian dynamics/kinetic Monte Carlo (BD/kMC) simulations of polymer melts. In this study, this methodology is extended for dynamical simulations of crosslinked polymer networks in a coarse-grained representation, wherein chains are modeled as sequences of beads, each bead encompassing a few Kuhn segments. In addition, the C++ code embodying these simulations, entitled Engine for Mesoscopic Simulations for Polymer Networks (EMSIPON) is described in detail. A crosslinked network of cis-1,4-polyisoprene is chosen as a test system. From the thermodynamic point of view, the system is fully described by a Helmholtz energy consisting of three explicit contributions: entropic springs, slip springs and non-bonded interactions. Entanglements between subchains in the network are represented by slip springs. The ends of the slip springs undergo thermally activated hops between adjacent beads along the chain backbones, which are tracked by kinetic Monte Carlo simulation. In addition, creation/destruction processes are included for the slip springs at dangling subchain ends. The Helmholtz energy of non-bonded interactions is derived from the Sanchez–Lacombe equation of state. The isothermal compressibility of the polymer network is predicted from equilibrium density fluctuations in very good agreement with the underlying equation of state and with experiment. Moreover, the methodology and the corresponding C++ code are applied to simulate elongational deformations of polymer rubbers. The shear stress relaxation modulus is predicted from equilibrium simulations of several microseconds of physical time in the undeformed state, as well as from stress-strain curves of the crosslinked polymer networks under deformation. Full article
(This article belongs to the Special Issue Theory and Simulations of Entangled Polymers)
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Open AccessArticle The Continuum Approach to the Description of Semi-Crystalline Polymers Deformation Regimes: The Role of Dynamic and Translational Defects
Polymers 2018, 10(10), 1155; https://doi.org/10.3390/polym10101155 (registering DOI)
Received: 24 August 2018 / Revised: 12 October 2018 / Accepted: 13 October 2018 / Published: 16 October 2018
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Abstract
This paper presents a new approach to describe the mechanical behavior of semi-crystalline polymers, the plastic deformation of which is determined by their two-phase structure. To describe the plastic behavior of semi-crystalline polymers, a two-phase model is used. In the framework of this
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This paper presents a new approach to describe the mechanical behavior of semi-crystalline polymers, the plastic deformation of which is determined by their two-phase structure. To describe the plastic behavior of semi-crystalline polymers, a two-phase model is used. In the framework of this model, one phase is in a hard (crystalline) state, and the other in a soft (amorphous) state. The two-phase material is modeled by a single-phase homogeneous continuum based on the approximation of the effective medium. It is assumed that two infinitely close material points of the continuum are connected in series by elastic and viscous bonds, which corresponds to the Maxwell model. It is shown that, in this case, the Maxwell continuum is a pseudo-Euclidean space. Generalizing the definition of defects from a three-dimensional space to a four-dimensional pseudo-Euclidean space, we obtained a dynamic system of nonlinear, interrelated equations to describe the behavior of translational-type defects in the solid phase and dynamic defects in the amorphous phase. As an example of an application for these equations, the phenomenon of creep under uniaxial loading is considered. It is shown that the formalism of the proposed two-phase model makes it possible to describe creep phenomenon regularities, which correspond to both the aging theory and the flow theory. Full article
(This article belongs to the Special Issue Mechanical Behavior of Polymers)
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Open AccessArticle Effects of Calcium Alginate Submicroparticles on Seed Germination and Seedling Growth of Wheat (Triticum aestivum L.)
Polymers 2018, 10(10), 1154; https://doi.org/10.3390/polym10101154 (registering DOI)
Received: 20 September 2018 / Revised: 5 October 2018 / Accepted: 6 October 2018 / Published: 16 October 2018
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Abstract
Calcium alginate (CaAlg) submicroparticles have a potential application in agricultural delivery systems. This study investigated the effects of CaAlg submicroparticles on seed germination and seedling growth of wheat. CaAlg submicroparticles with a Z-average diameter of around 250.4 nm and a measured zeta potential
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Calcium alginate (CaAlg) submicroparticles have a potential application in agricultural delivery systems. This study investigated the effects of CaAlg submicroparticles on seed germination and seedling growth of wheat. CaAlg submicroparticles with a Z-average diameter of around 250.4 nm and a measured zeta potential value of about −25.4 mV were prepared and characterized by dynamic light scattering (DLS), scanning electron microscopy (SEM) and energy dispersive X-ray spectrometer (EDS). After this, the effects of the concentration of CaAlg submicroparticles (10–500 μg/mL) on germination percentage, seedling length, the number of adventitious roots, chlorophyll content and soluble protein content were evaluated. The results demonstrated a significant increase in the level of germination percentage (9.0%), seedling index (50.3%), adventitious roots (27.5%), seedling length (17.0%), chlorophyll (8.7%) and soluble protein contents (4.5%) at a concentration of 100 μg/mL. However, an inhibitory effect was observed at a concentration of 500 μg/mL. The SEM examination showed that CaAlg submicroparticles could be successfully adsorbed onto the surface of the wheat seed. Further studies proved that CaAlg submicroparticles at a concentration of 100 μg/mL promoted the expression of indole-3-acetic acid (IAA)-related genes (YUCCA9, AUX1, ARF and UGT) in wheat, which resulted in an increase of 69% and 21% in IAA concentration in wheat roots and shoots, respectively. Full article
(This article belongs to the Special Issue Polysaccharides)
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Open AccessArticle Mechanisms of the Complex Thermo-Mechanical Behavior of Polymer Glass Across a Wide Range of Temperature Variations
Polymers 2018, 10(10), 1153; https://doi.org/10.3390/polym10101153 (registering DOI)
Received: 26 September 2018 / Revised: 13 October 2018 / Accepted: 15 October 2018 / Published: 16 October 2018
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Abstract
This paper aims to explore the mechanisms of the complex thermo-mechanical behavior of polymer glass across a wide range of temperature variations. To this end, the free vibration frequency spectrum of simply supported poly(methyl methacrylate) (PMMA) beams was thoroughly investigated with the aid
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This paper aims to explore the mechanisms of the complex thermo-mechanical behavior of polymer glass across a wide range of temperature variations. To this end, the free vibration frequency spectrum of simply supported poly(methyl methacrylate) (PMMA) beams was thoroughly investigated with the aid of the impulse excitation technique. It was found that the amplitude ratio of the multiple peaks in the frequency spectrum is a strongly dependent on temperature, and that the peaks correspond to the multiple vibrational modes of the molecular network of PMMA. At a low temperature, the vibration is dominated by the overall microstructure of PMMA. With increasing the temperature, however, the contribution of the sub-microstructures is retarded by β relaxation. Above 80 °C, the vibration is fully dominated by the microstructure after relaxation. The relaxation time at the transition temperature is of the same order of the vibration period, confirming the contribution of β relaxation. These findings provide a precise method for establishing reliable physical-based constitutive models of polymer glass. Full article
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Open AccessArticle Recycled Carbon Fiber-Supported Polyaniline/Manganese Dioxide Prepared via One-Step Electrodeposition for Flexible Supercapacitor Integrated Electrodes
Polymers 2018, 10(10), 1152; https://doi.org/10.3390/polym10101152 (registering DOI)
Received: 12 September 2018 / Revised: 11 October 2018 / Accepted: 12 October 2018 / Published: 16 October 2018
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Abstract
The exploration of multifunctional electrode materials has been a hotspot for the development of high-performance supercapacitors. We have used carbon fiber plates recovered from construction waste to prepare high-quality flexible carbon fiber materials by pyrolysis of epoxy resin. The as-prepared recycled carbon fiber
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The exploration of multifunctional electrode materials has been a hotspot for the development of high-performance supercapacitors. We have used carbon fiber plates recovered from construction waste to prepare high-quality flexible carbon fiber materials by pyrolysis of epoxy resin. The as-prepared recycled carbon fiber has a diameter of 8 μm and is the perfect substrate material for flexible electrode materials. Furthermore, polyaniline and manganese dioxide are uniformly deposited on the recycled carbon fiber by one-step electrodeposition to form an active film. The recycled carbon fiber/polyaniline/MnO2 composite shows an excellent specific capacitance of 475.1 F·g−1 and capacitance retention of 86.1% after 5000 GCD cycles at 1 A·g−1 in 1 M Na2SO4 electrolyte. The composites optimized for electrodeposition time have more electroactive sites, faster ions and electron transfer, structural stability and higher conductivity, endowing the composites promising application prospect. Full article
(This article belongs to the Special Issue Polymers for Energy Applications)
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Open AccessArticle Facile Route for Bio-Phenol Siloxane Synthesis via Heterogeneous Catalytic Method and its Autonomic Antibacterial Property
Polymers 2018, 10(10), 1151; https://doi.org/10.3390/polym10101151
Received: 12 September 2018 / Revised: 9 October 2018 / Accepted: 11 October 2018 / Published: 16 October 2018
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Abstract
Eugenol, used as bio-phenol, was designed to replace the hydrogen atom of hydrogenterminated siloxane by hydrosilylation reaction under the presence of alumina-supported platinum catalyst (Pt-Al2O3), silica-supported platinum catalyst (Pt-SiO2) and carbon nanotube-supported platinum catalyst (Pt-CNT), respectively. The
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Eugenol, used as bio-phenol, was designed to replace the hydrogen atom of hydrogenterminated siloxane by hydrosilylation reaction under the presence of alumina-supported platinum catalyst (Pt-Al2O3), silica-supported platinum catalyst (Pt-SiO2) and carbon nanotube-supported platinum catalyst (Pt-CNT), respectively. The catalytic activities of these three platinum catalysts were measured by nuclear magnetic resonance hydrogen spectrometer (1H NMR). The properties of bio-phenol siloxane were characterized by Fourier transform infrared spectrometer (FT–IR), UV-visible spectrophotometer (UV) and thermogravimeter (TGA), and its antibacterial property against Escherichia coli was also studied. The results showed that the catalytic activity of the catalyst Pt-CNT was preferable. When the catalyst concentration was 100 ppm, the reaction temperature was 80 °C and reaction time was 6 h, the reactant conversion rate reached 97%. After modification with bio-phenol, the thermal stability of the obtained bio-phenol siloxane was improved. For bio-phenol siloxane, when the ratio of weight loss reached 98%, the pyrolysis temperature was raised to 663 °C which was 60 °C higher than hydrogenterminated siloxane. Meanwhile, its autonomic antibacterial property against Escherichia coli was improved significantly. Full article
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Open AccessArticle A Phenolphthalein-Dummy Template Molecularly Imprinted Polymer for Highly Selective Extraction and Clean-Up of Bisphenol A in Complex Biological, Environmental and Food Samples
Polymers 2018, 10(10), 1150; https://doi.org/10.3390/polym10101150
Received: 13 September 2018 / Revised: 5 October 2018 / Accepted: 12 October 2018 / Published: 15 October 2018
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Abstract
A molecularly imprinted polymer (MIP) for highly selective solid-phase extraction (SPE) of bisphenol A (BPA) was prepared using phenolphthalein (PP) as the novel dummy template by bulk polymerization. A particle diameter distribution of 40–60 μm, a specific surface area of 359.8 m2
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A molecularly imprinted polymer (MIP) for highly selective solid-phase extraction (SPE) of bisphenol A (BPA) was prepared using phenolphthalein (PP) as the novel dummy template by bulk polymerization. A particle diameter distribution of 40–60 μm, a specific surface area of 359.8 m2·g−1, and a total pore volume of 0.730 cm3·g−1 for the prepared PP-imprinted polymer (PPMIP) were obtained. Good selectivity and specific adsorption capacity for BPA of the prepared PPMIP were also demonstrated by the chromatographic evaluation and sorption experiments. The PPMIP as a SPE sorbent was evaluated for the selective extraction and clean-up of BPA from complex biological, environmental, and food samples. Meanwhile, an accurate and sensitive analytical method based on the PPMIP-SPE purification procedure coupled with high performance liquid chromatography-diode array detector (HPLC-DAD) detection has been successfully developed for the rapid determination of BPA from these samples, with detection limits of 1.3 ng·mL−1 for bovine serum and milk, 2.6 ng·mL−1 for human urine and edible oil, 5.2 ng·mL−1 for soybean sauce, and 1.3 ng·g−1 for sediment. The BPA recoveries at two different spiking levels were in the range of 82.1–106.9%, with relative standard deviation (RSD) values below 7.7%. Full article
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Open AccessArticle Novel Kinetic Models of Xylan Dissolution and Degradation during Ethanol Based Auto-Catalyzed Organosolv Pretreatment of Bamboo
Polymers 2018, 10(10), 1149; https://doi.org/10.3390/polym10101149
Received: 25 September 2018 / Revised: 8 October 2018 / Accepted: 12 October 2018 / Published: 15 October 2018
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Abstract
Due to the invalidity of traditional models, pretreatment conditions dependent parameter of susceptible dissolution degree of xylan (dX) was introduced into the kinetic models. After the introduction of dX, the dissolution of xylan, and the formation of xylo-oligosaccharides and
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Due to the invalidity of traditional models, pretreatment conditions dependent parameter of susceptible dissolution degree of xylan (dX) was introduced into the kinetic models. After the introduction of dX, the dissolution of xylan, and the formation of xylo-oligosaccharides and xylose during ethanol based auto-catalyzed organosolv (EACO) pretreatments of bamboo were well predicted by the pseudo first-order kinetic models (R2 > 97%). The parameter of dX was verified to be a variable dependent of EACO pretreatment conditions (such as solvent content in pretreatment liquor and pretreatment temperature). Based on the established kinetic models of xylan dissolution, the dissolution of glucan and the formation of degradation products (furfural and acetic acid) could also be empirically modeled (R2 > 97%). In addition, the relationship between xylan and lignin removal can provide guidance for alleviating the depositions of lignin or pseudo-lignin. The parameter of dX derived novel kinetic models can not only be used to reveal the multi-step reaction mechanisms of xylan, but also control the final removal of main components in bamboo during EACO pretreatments, indicating scientific and practical significance for governing the biorefinery of woody biomass. Full article
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Open AccessArticle Influence of Biopolymer Carrageenan and Glycerine on the Properties of Extrusion Printed Inks of Carbon Nanotubes
Polymers 2018, 10(10), 1148; https://doi.org/10.3390/polym10101148
Received: 10 September 2018 / Revised: 10 October 2018 / Accepted: 11 October 2018 / Published: 15 October 2018
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Abstract
This article focuses on the preparation of extrusion printing composite inks of multiwall carbon nanotube (MWNT) dispersed separately in iota-carrageenan (IC) and glycerine (G) solution. Both composites (IC-MWNT and G-MWNT) showed shear-thinning behavior when their flow characteristics were tested. Conductive solid tracks/patterns of
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This article focuses on the preparation of extrusion printing composite inks of multiwall carbon nanotube (MWNT) dispersed separately in iota-carrageenan (IC) and glycerine (G) solution. Both composites (IC-MWNT and G-MWNT) showed shear-thinning behavior when their flow characteristics were tested. Conductive solid tracks/patterns of both printed composite inks were deposited on glass slide, PET (polyethylene terephthalate) sheet, and IC gel films substrates. The conductive patterns were characterized with microscopy, scanning electron microscopy (SEM), and profilometer. Moreover, their contact angle and electrical conductivity were measured. Profilometry showed that increased number of extruded layers gave increased cross-sectional area. SEM study showed that printing ink is embedded into the surface of IC film, discontinuous on glass slide and smoother on PET sheet. Conductivity of IC-MWNT track was 9 ± 1 S/m and that of G-MWNT was 2942 ± 84 S/m on glass substrate of one layer thick. This is because fewer carbon nanotubes (CNT) are present in G-MWNT track as confirmed by SEM study. The nature of substrate also affects the conductivity of printed patterns. The impressive result of conductivity of printed patterns of composite inks can make them useful for bioelectronic application. Full article
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Open AccessArticle The Influence of Fiber Cross-Section on Fabric Far-Infrared Properties
Polymers 2018, 10(10), 1147; https://doi.org/10.3390/polym10101147
Received: 13 August 2018 / Revised: 27 September 2018 / Accepted: 12 October 2018 / Published: 14 October 2018
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Abstract
Far-infrared radiation (FIR) possesses various promising properties that are beneficial to an individuals’ health. Exploring the interaction between fiber shapes and FIR performance is thought to be a significant means to develop highly-efficient FIR textile products. In this study, a non-additive triangular polyamide
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Far-infrared radiation (FIR) possesses various promising properties that are beneficial to an individuals’ health. Exploring the interaction between fiber shapes and FIR performance is thought to be a significant means to develop highly-efficient FIR textile products. In this study, a non-additive triangular polyamide (PA) fiber showed excellent FIR properties in both theoretical simulation and experimental verification aspects. The triangular PA fiber affords a higher probability to facilitate large optical path difference, improving both FIR absorption and emission. Textiles woven with the specific triangular PA fiber achieved a remarkable emissivity of 91.85% and temperature difference of 2.11 Celsius, which is obviously superior to the reference circular fiber (86.72%, 1.52 Celsius). Considering the low cost, environmental stability, facile fabrication, as well as being environmentally friendly, this non-additive triangular PA fiber has great potential for high-performance and cost-effective FIR textiles in the future. Full article
(This article belongs to the Special Issue Polymer Processing for Enhancing Textile Application)
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Open AccessReview Intra- and Interpolyelectrolyte Complexes of Polyampholytes
Polymers 2018, 10(10), 1146; https://doi.org/10.3390/polym10101146
Received: 4 September 2018 / Revised: 8 October 2018 / Accepted: 9 October 2018 / Published: 14 October 2018
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Abstract
At present, a large amount of research from experimental and theoretical points of view has been done on interpolyelectrolyte complexes formed by electrostatic attractive forces and/or interpolymer complexes stabilized by hydrogen bonds. By contrast, relatively less attention has been given to polymer–polymer complex
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At present, a large amount of research from experimental and theoretical points of view has been done on interpolyelectrolyte complexes formed by electrostatic attractive forces and/or interpolymer complexes stabilized by hydrogen bonds. By contrast, relatively less attention has been given to polymer–polymer complex formation with synthetic polyampholytes (PA). In this review the complexation of polyampholytes with polyelectrolytes (PE) is considered from theoretical and application points of view. Formation of intra- and interpolyelectrolyte complexes of random, regular, block, dendritic polyampholytes are outlined. A separate subsection is devoted to amphoteric behavior of interpolyelectrolyte complexes. The realization of the so-called “isoelectric effect” for interpolyelectrolyte complexes of water-soluble polyampholytes, amphoteric hydrogels and cryogels with respect to surfactants, dye molecules, polyelectrolytes and proteins is demonstrated. Full article
(This article belongs to the Special Issue Interpolymer Complexes)
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Open AccessArticle Isolation and Characterization of Cellulose Nanocrystals from Rejected Fibers Originated in the Kraft Pulping Process
Polymers 2018, 10(10), 1145; https://doi.org/10.3390/polym10101145
Received: 22 September 2018 / Revised: 9 October 2018 / Accepted: 10 October 2018 / Published: 14 October 2018
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Abstract
In the final process of the bleached kraft pulp there are some cellulose fibers that are separated from the main fibers stream; these fibers are rejected and considered as a low quality fibers, these fibers are known as rejected fiber (RF). In the
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In the final process of the bleached kraft pulp there are some cellulose fibers that are separated from the main fibers stream; these fibers are rejected and considered as a low quality fibers, these fibers are known as rejected fiber (RF). In the present work the potential use of these fibers for Cellulose Nanocrystals (CNCs) synthesis was studied. The physical and chemical properties of synthesized CNCs were characterized through different techniques such as Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), and Thermogravimetric Analysis (TGA). Results demonstrate the feasibility of CNCs synthesis with a yield of 28.1% and 36.9%, and crystallinity of 73.5% and 82.7%. Finally, the morphology and synthesis conditions suggest that this industrial reject fiber (RF) could be used as a source for the CNCs production, thus adding value to the kraft process and opening new possibilities for innovation in the pulp industry. Full article
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Open AccessArticle Use of Orange Oil Loaded Pectin Films as Antibacterial Material for Food Packaging
Polymers 2018, 10(10), 1144; https://doi.org/10.3390/polym10101144
Received: 24 September 2018 / Revised: 11 October 2018 / Accepted: 11 October 2018 / Published: 14 October 2018
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Abstract
This study aims to develop orange oil loaded in thin mango peel pectin films and evaluate their antibacterial activity against Staphylococcus aureus. The mango peel pectin was obtained from the extraction of ripe Nam Dokmai mango peel by the microwave-assisted method. The thin
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This study aims to develop orange oil loaded in thin mango peel pectin films and evaluate their antibacterial activity against Staphylococcus aureus. The mango peel pectin was obtained from the extraction of ripe Nam Dokmai mango peel by the microwave-assisted method. The thin films were formulated using commercial low methoxy pectin (P) and mango pectin (M) at a ratio of 1:2 with and without glycerol as a plasticizer. Orange oil was loaded into the films at 3% w/w. The orange oil film containing P and M at ratio of 1:2 with 40% w/w of glycerol (P1M2GO) showed the highest percent elongation (12.93 ± 0.89%) and the lowest Young’s modulus values (35.24 ± 3.43 MPa). For limonene loading content, it was found that the amount of limonene after the film drying step was directly related to the final physical structure of the film. Among the various tested films, P1M2GO film had the lowest limonene loading content (59.25 ± 2.09%), which may be because of the presence of numerous micropores in the P1M2GO film’s matrix. The inhibitory effect against the growth of S. aureus was compared in normalized value of clear zone diameter using the normalization value of limonene content in each film. The P1M2GO film showed the highest inhibitory effect against S. aureus with the normalized clear zone of 11.75 mm but no statistically significant difference. This study indicated that the orange oil loaded in mango peel pectin film can be a valuable candidate as antibacterial material for food packaging. Full article
(This article belongs to the Special Issue Antimicrobial Polymer-Based Materials for Food Packaging Applications)
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Open AccessArticle Morphologies Tuning of Polypyrrole and Thermoelectric Properties of Polypyrrole Nanowire/Graphene Composites
Polymers 2018, 10(10), 1143; https://doi.org/10.3390/polym10101143
Received: 11 August 2018 / Revised: 28 September 2018 / Accepted: 29 September 2018 / Published: 13 October 2018
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Abstract
Polypyrrole (PPy) with different morphologies (e.g., particles, nanotubes, and nanowires) were successfully prepared by adding or without adding different kinds of surfactants through a chemical oxidative polymerization method, respectively. The results show that the morphologies of PPy can be effectively controlled and have
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Polypyrrole (PPy) with different morphologies (e.g., particles, nanotubes, and nanowires) were successfully prepared by adding or without adding different kinds of surfactants through a chemical oxidative polymerization method, respectively. The results show that the morphologies of PPy can be effectively controlled and have a significantly effects on their thermoelectric properties. The PPy nanowires exhibit the highest electrical conductivity and Seebeck coefficient among the various PPy morphologies, such as particles, nanotubes, and nanowires, so PPy nanowires were chosen to prepare PPy nanowire/graphene thermoelectric composites via a soft template polymerization method using cetyltrimethyl ammonium bromide as the template. Both electrical conductivity and Seebeck coefficient of the PPy nanowire/graphene composites increased as the content of graphene increases from 0 to 20 wt %, and as the measured temperature increases from 300 K to 380 K, which leds to the same trend for the power factor. A highest power factor of 1.01 μWm−1K−2 at ~380 K was obtained for the PPy nanowire/graphene composites with 20 wt % PPy nanowire, which is about 3.3 times higher than that of the pure PPy nanowire. Full article
(This article belongs to the Special Issue Polymers for Thermoelectric Application)
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Open AccessArticle Enhancement of Plasticizing Effect on Bio-Based Polyurethane Acrylate Solid Polymer Electrolyte and Its Properties
Polymers 2018, 10(10), 1142; https://doi.org/10.3390/polym10101142
Received: 6 September 2018 / Revised: 8 October 2018 / Accepted: 9 October 2018 / Published: 12 October 2018
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Abstract
Polyurethane acrylate (PUA) from vegetable oil has been synthesized and prepared for solid polymer electrolyte. Polyol has been end-capped with Toluene 2,4-Diisocyanate (TDI) followed by hydroxylethylmethylacrylate (HEMA) in a urethanation process to produce PUA. The mixtures were cured to make thin polymeric films
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Polyurethane acrylate (PUA) from vegetable oil has been synthesized and prepared for solid polymer electrolyte. Polyol has been end-capped with Toluene 2,4-Diisocyanate (TDI) followed by hydroxylethylmethylacrylate (HEMA) in a urethanation process to produce PUA. The mixtures were cured to make thin polymeric films under UV radiation to produce excellent cured films which exhibit good thermal stability and obtain high ionic conductivity value. 3 to 15 wt. % of ethylene carbonate (EC) mixed with 25 wt. % LiClO4 was added to PUA to obtain PUA electrolyte systems. PUA modified with plasticizer EC 9 wt. % achieved the highest conductivity of 7.86 × 10−4 S/cm, and relatively improved the linear sweep voltammetry, transference number and dielectric properties. Fourier Transform Infrared Spectroscopy (FTIR) and dielectric analysis were presented. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), followed by X-ray Diffraction (XRD) and morphology have been studied. The addition of plasticizer to the polyurethane acrylate shows significant improvement in terms of the conductivity and performance of the polymer electrolyte. Full article
(This article belongs to the Special Issue Ionic Polymers)
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Open AccessArticle Polymers from Bamboo Extracts Produced by Laccase
Polymers 2018, 10(10), 1141; https://doi.org/10.3390/polym10101141
Received: 13 September 2018 / Revised: 27 September 2018 / Accepted: 9 October 2018 / Published: 12 October 2018
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Abstract
A green methodology for the production of polymers from bamboo powder was investigated. The optimal conditions for the extraction of components from bamboo were defined by incubating the powder in an acetate buffer (pH 5) under boiling for 2 h. Native laccase from
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A green methodology for the production of polymers from bamboo powder was investigated. The optimal conditions for the extraction of components from bamboo were defined by incubating the powder in an acetate buffer (pH 5) under boiling for 2 h. Native laccase from Myceliophthora thermophila was used afterwards to oxidize the extracts from the final resulting extraction liquid. The reduction of the free OH content after enzymatic oxidation, as well as the 1H NMR data, confirmed the efficient polymerization of the extracts. The bamboo powder samples were also subjected to high compression and curing, in the absence and in the presence of laccase, to evaluate the hardness of the tablets formed by enzymatic bonding events. The results revealed a higher hardness when the tablets were produced in the presence of laccase, confirming the role of the catalyst on the precipitation of colloidal lignin and phenolic extractives. Herein we produce new oligomers/polymers by laccase oxidation of the extracts resulting from a clean method boiling. At the same time, the data open up new routes for the exploitation of new lignocellulosic materials by the direct application of the enzyme on the bamboo powder material. Full article
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Open AccessCommunication π-Stacked Polymer Consisting of a Pseudo–meta–[2.2]Paracyclophane Skeleton
Polymers 2018, 10(10), 1140; https://doi.org/10.3390/polym10101140
Received: 27 August 2018 / Revised: 26 September 2018 / Accepted: 2 October 2018 / Published: 12 October 2018
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Abstract
A novel π-stacked polymer based on a pseudo–meta–linked [2.2]paracyclophane moieties was synthesized by Sonogashira-Hagihara coupling. The UV-vis absorption spectra of the synthesized polymer and model compounds revealed an extension of the conjugation length owing to the through-space conjugation. The optical properties
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A novel π-stacked polymer based on a pseudo–meta–linked [2.2]paracyclophane moieties was synthesized by Sonogashira-Hagihara coupling. The UV-vis absorption spectra of the synthesized polymer and model compounds revealed an extension of the conjugation length owing to the through-space conjugation. The optical properties of the π-stacked dimer with the pseudo–meta–linked [2.2]paracyclophane unit were compared with those of the corresponding dimers with the pseudo–ortho– and pseudo–para–linked [2.2]paracyclophane units. Full article
(This article belongs to the Special Issue π-Stacked Polymers)
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Open AccessArticle Thermo-Mechanical Characterisations of Flax Fibre and Thermoplastic Resin Composites during Manufacturing
Polymers 2018, 10(10), 1139; https://doi.org/10.3390/polym10101139
Received: 23 September 2018 / Revised: 4 October 2018 / Accepted: 10 October 2018 / Published: 12 October 2018
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Abstract
The flax fibre reinforced composites with advanced structure, which can be regarded as recyclable parts, are potential and promising materials in the automobile industry. During their manufacturing, the reinforcements or prepregs should be performed to the desired shape beforehand. Mechanical behaviours accordingly play
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The flax fibre reinforced composites with advanced structure, which can be regarded as recyclable parts, are potential and promising materials in the automobile industry. During their manufacturing, the reinforcements or prepregs should be performed to the desired shape beforehand. Mechanical behaviours accordingly play an important role during this process. However, this preforming process is usually under high temperatures, thus, the mechanical behaviours could be modified under this state. Especially for reinforcements produced by flax yarns, has barely been studied. To fill this gap, in this paper the thermos-mechanical characterization of Flax/Polyamide12 (PA12) commingled yarn and prepreg woven fabric is analysed using tensile and in-plane shearing tests under different temperatures and tensile speeds. The results conclusively show that strength can be improved by increasing the temperature below the PA12 melting value on woven fabrics, which is inverse tendency for single yarn. Moreover, increasing tensile speed could increase the strength of the single yarn and fabric. This reveals that the PA12 fluidity has great influence on tensile behaviour. The characterisation results would be employed as prescriptive recommendations in the process of manufacturing flax fibre-reinforced composite parts. Full article
(This article belongs to the Special Issue Polymer Processing for Enhancing Textile Application)
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Open AccessArticle Inorganic and Organic Hybrid Nanoparticles as Multifunctional Crosslinkers for Rubber Vulcanization with High-Filler Rubber Interaction
Polymers 2018, 10(10), 1138; https://doi.org/10.3390/polym10101138
Received: 30 August 2018 / Revised: 6 October 2018 / Accepted: 9 October 2018 / Published: 12 October 2018
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Abstract
Improving the interfacial interaction between rubber and silica nanoparticles, and simultaneously reducing free sulfur and preventing migration and volatilization of a rubber vulcanizing agent, commercial sulfur compound aliphatic ether polysulfide (VA-7) was chemically attached to the silica surface to obtain a functionalized nanoparticle
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Improving the interfacial interaction between rubber and silica nanoparticles, and simultaneously reducing free sulfur and preventing migration and volatilization of a rubber vulcanizing agent, commercial sulfur compound aliphatic ether polysulfide (VA-7) was chemically attached to the silica surface to obtain a functionalized nanoparticle (silica-s-VA7). Functional nanoparticles can not only effectively crosslink rubber without sulfur as a novel vulcanizator, but are also evenly dispersed in the rubber matrix and improve the dispersion of the remaining pristine silica as an interfacial compatibilizer. In addition, the thicker immobilized polymer layer and prominent crosslinking density of SBR nanocomposites simultaneously demonstrate that the novel vulcanizing agent silica-s-VA7 gives rise to significant improvement on the rubber–filler interfacial adhesion on account of the covalent linkages of organic and inorganic interfaces between elastomer and nanofillers. We envisage that this strategy may provide a new avenue to implement high-efficiency design for a multifunctional rubber-vulcanizing agent through an organic and inorganic hybridization mechanism. Full article
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Open AccessArticle Development of a Semiglobal Reaction Mechanism for the Thermal Decomposition of a Polymer Containing Reactive Flame Retardants: Application to Glass-Fiber-Reinforced Polybutylene Terephthalate Blended with Aluminum Diethyl Phosphinate and Melamine Polyphosphate
Polymers 2018, 10(10), 1137; https://doi.org/10.3390/polym10101137
Received: 17 September 2018 / Revised: 8 October 2018 / Accepted: 10 October 2018 / Published: 12 October 2018
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Abstract
This work details a methodology for parameterization of the kinetics and thermodynamics of the thermal decomposition of polymers blended with reactive additives. This methodology employs Thermogravimetric Analysis, Differential Scanning Calorimetry, Microscale Combustion Calorimetry, and inverse numerical modeling of these experiments. Blends of glass-fiber-reinforced
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This work details a methodology for parameterization of the kinetics and thermodynamics of the thermal decomposition of polymers blended with reactive additives. This methodology employs Thermogravimetric Analysis, Differential Scanning Calorimetry, Microscale Combustion Calorimetry, and inverse numerical modeling of these experiments. Blends of glass-fiber-reinforced polybutylene terephthalate (PBT) with aluminum diethyl phosphinate and melamine polyphosphate were used to demonstrate this methodology. These additives represent a potent solution for imparting flame retardancy to PBT. The resulting lumped-species reaction model consisted of a set of first- and second-order (two-component) reactions that defined the rate of gaseous pyrolyzate production. The heats of reaction, heat capacities of the condensed-phase reactants and products, and heats of combustion of the gaseous products were also determined. The model was shown to reproduce all aforementioned experiments with a high degree of detail. The model also captured changes in the material behavior with changes in the additive concentrations. Second-order reactions between the material constituents were found to be necessary to reproduce these changes successfully. The development of such models is an essential milestone toward the intelligent design of flame retardant materials and solid fuels. Full article
(This article belongs to the Special Issue Flame Retardancy of Polymeric Materials)
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Open AccessArticle Enhanced Adsorption of Bisphenol A from Aqueous Solution with 2-Vinylpyridine Functionalized Magnetic Nanoparticles
Polymers 2018, 10(10), 1136; https://doi.org/10.3390/polym10101136
Received: 11 September 2018 / Revised: 2 October 2018 / Accepted: 10 October 2018 / Published: 12 October 2018
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Abstract
In this study, a novel 2-vinylpyridine functionalized magnetic nanoparticle (Mag-PVP) was successfully prepared. The prepared Mag-PVP was characterized by transmission electronic microscopy (TEM), Fourier transform infrared spectrophotometry (FT-IR), vibrating sample magnetometry (VSM) and thermogravimetric analysis (TGA), and was used for the adsorption of
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In this study, a novel 2-vinylpyridine functionalized magnetic nanoparticle (Mag-PVP) was successfully prepared. The prepared Mag-PVP was characterized by transmission electronic microscopy (TEM), Fourier transform infrared spectrophotometry (FT-IR), vibrating sample magnetometry (VSM) and thermogravimetric analysis (TGA), and was used for the adsorption of bisphenol A (BPA) from aqueous solutions. Mag-PVP, which is composed of Fe3O4 nanoparticles and poly divinylbenzene-2-vinylpyridine (with a thickness of 10 nm), exhibited magnetic properties (Ms = 44.6 emu/g) and thermal stability. The maximum adsorption capacity (Qm) of Mag-PVP for BPA obtained from the Langmuir isotherm was 115.87 mg/g at 20 °C, which was more than that of Fe3O4 nanospheres. In the presence of NaCl, the improved adsorption capacity of Mag-PVP was probably attributed to the screening effect of Mag-PVP surface charge and salting-out effect. In the presence of CaCl2 and humic acid (HA), the adsorption capacity of BPA decreased due to competitive adsorption. The adsorption of BPA by Mag-PVP increased slightly with the increase in pH from 3.0 to 5.0 and obtained the largest adsorption amount at pH 5.0, which was probably attributed to hydrogen bonding interactions. Moreover, in actual water, Mag-PVP still showed excellent adsorption performance in removing BPA. The high adsorption capacity and excellent reusability performance in this work indicated that Mag-PVP was an effective adsorbent for removing BPA from aqueous solutions. Full article
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Open AccessArticle Optimization of Mechanical and Thermal Properties of iPP and LMPP Blend Fibres by Surface Response Methodology
Polymers 2018, 10(10), 1135; https://doi.org/10.3390/polym10101135
Received: 8 August 2018 / Revised: 25 September 2018 / Accepted: 10 October 2018 / Published: 12 October 2018
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Abstract
Optimization of the mechanical and thermal properties of isotactic polypropylene (iPP) homopolymer blended with relatively new low molecular low modulus polypropylene (LMPP) at different blend ratios was carried out via surface response methodology (RSM). Regression equations for the prediction of optimal conditions were
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Optimization of the mechanical and thermal properties of isotactic polypropylene (iPP) homopolymer blended with relatively new low molecular low modulus polypropylene (LMPP) at different blend ratios was carried out via surface response methodology (RSM). Regression equations for the prediction of optimal conditions were achieved considering eight individual parameters: naming, elongation at break, tensile strength and elastic modulus, crystallization temperature (TC), first melting temperatures (TM1), heat fusion (Hf), crystallinity, and melt flow rate (MFR), which were measured as responses for the design of experiment (DOE). The adjusted and predicted correlation coefficient (R2) shows good agreement between the actual and the predicted values. To confirm the optimal values from the response model, supplementary experiments as a performance evaluation were conducted, posing better operational conditions. It has been confirmed that the RSM model was adequate to reflect the predicted optimization. The results suggest that the addition of LMPP into iPP could effectively enhance the functionality and processability of blend fibres if correctly proportioned. Full article
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Open AccessArticle Novel Photocatalytic PVDF/Nano-TiO2 Hollow Fibers for Environmental Remediation
Polymers 2018, 10(10), 1134; https://doi.org/10.3390/polym10101134
Received: 1 August 2018 / Revised: 6 October 2018 / Accepted: 9 October 2018 / Published: 12 October 2018
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Abstract
Polyvinylidene difluoride (PVDF) mixed matrix membranes loaded with inorganic TiO2 nanoparticles have received increasing attention in the last few years as self-cleaning membranes for possible application in wastewater treatment and seawater filtration. These novel membranes show increased hydrophilicity, stability and catalytic activity
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Polyvinylidene difluoride (PVDF) mixed matrix membranes loaded with inorganic TiO2 nanoparticles have received increasing attention in the last few years as self-cleaning membranes for possible application in wastewater treatment and seawater filtration. These novel membranes show increased hydrophilicity, stability and catalytic activity under UV-A irradiation. In this work, PVDF-TiO2 hollow fibers were prepared by employing new strategies for enhancing the stability of the TiO2 dispersion, reducing particle agglomeration and improving their distribution. The spinning conditions for producing ultrafiltration hollow fiber membranes from PVDF material and nano-TiO2 were investigated. Finally, the optimized fibers have been characterized and tested for methylene blue (MB) degradation in water and salty seawater, revealing good permeability, long-term stability under UV-A irradiation, and photo-catalytic activity in both test solutions. Full article
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Open AccessReview Hyaluronic Acid-Based Nanomaterials for Cancer Therapy
Polymers 2018, 10(10), 1133; https://doi.org/10.3390/polym10101133
Received: 30 July 2018 / Revised: 22 September 2018 / Accepted: 9 October 2018 / Published: 12 October 2018
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Abstract
Hyaluronic acid (HA) is a nonsulfated glycosaminoglycan and a major component of the extracellular matrix. HA is overexpressed by numerous tumor cells, especially tumor-initiating cells. HA-based nanomaterials play in importance role in drug delivery systems. HA is used in various types of nanomaterials
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Hyaluronic acid (HA) is a nonsulfated glycosaminoglycan and a major component of the extracellular matrix. HA is overexpressed by numerous tumor cells, especially tumor-initiating cells. HA-based nanomaterials play in importance role in drug delivery systems. HA is used in various types of nanomaterials including micelle, polymersome, hydrogel, and inorganic nanoparticle formulations. Many experiments show that HA-based nanomaterials can serve as a platform for targeted chemotherapy, gene therapy, immunotherapy, and combination therapy with good potential for future biomedical applications in cancer treatment. Full article
(This article belongs to the Special Issue Polymeric Micro/Nanoparticles for Bio-Medical Applications)
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Open AccessArticle Effect of Chemical Composition Variant and Oxygen Plasma Treatments on the Wettability of PLGA Thin Films, Synthesized by Direct Copolycondensation
Polymers 2018, 10(10), 1132; https://doi.org/10.3390/polym10101132
Received: 7 September 2018 / Revised: 8 October 2018 / Accepted: 8 October 2018 / Published: 12 October 2018
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Abstract
The synthesis of high molecular weight poly (lactic-co-glycolic) acid (PLGA) copolymers via direct condensation copolymerization is itself a challenging task. Moreover, some of the characteristic properties of polylactide (PLA)-based biomaterials, such as brittleness, hydrophobicity, and longer degradation time, are not suitable
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The synthesis of high molecular weight poly (lactic-co-glycolic) acid (PLGA) copolymers via direct condensation copolymerization is itself a challenging task. Moreover, some of the characteristic properties of polylactide (PLA)-based biomaterials, such as brittleness, hydrophobicity, and longer degradation time, are not suitable for certain biomedical applications. However, such properties can be altered by the copolymerization of PLA with other biodegradable monomers, such as glycolic acid. A series of high molecular weight PLGAs were synthesized through the direct condensation copolymerization of lactic and glycolic acids, starting from 0 to 50 mol% of glycolic acid, and the wettability of its films was monitored as a function of the feed molar ratio. Copolymerization was performed in the presence of a bi-catalytic system using stannous chloride dihydrate and methanesulfonic acid (MSA). The viscosity average molecular weight of the resulting PLGA was in the range of 80k to 135k g/mol. The PLGA films were prepared using the solvent casting technique, and were treated with oxygen plasma for 2 min. The water contact angle of the PLGA films was determined before and after the oxygen plasma treatments, and it was observed that the wettability increased with an increase in the glycolic acid contents, however, the manifolds increased after 2 min of oxygen plasma treatments. Full article
(This article belongs to the Special Issue Biodegradable Polymers for Environmental and Medical Applications)
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Open AccessArticle Heat Dissipation in Epoxy/Amine-Based Gradient Composites with Alumina Particles: A Critical Evaluation of Thermal Conductivity Measurements
Polymers 2018, 10(10), 1131; https://doi.org/10.3390/polym10101131
Received: 30 July 2018 / Revised: 2 October 2018 / Accepted: 8 October 2018 / Published: 11 October 2018
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Abstract
For the design of the next generation of microelectronic packages, thermal management is one of the key aspects and must be met by the development of polymers with enhanced thermal conductivity. While all polymer classes show a very low thermal conductivity, this shortcoming
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For the design of the next generation of microelectronic packages, thermal management is one of the key aspects and must be met by the development of polymers with enhanced thermal conductivity. While all polymer classes show a very low thermal conductivity, this shortcoming can be compensated for by the addition of fillers, yielding polymer-based composite materials with high thermal conductivity. The inorganic fillers, however, are often available only in submicron- and micron-scaled dimensions and, consequently, can sediment during the curing reaction of the polymer matrix. In this study, an epoxy/amine resin was filled with nano- and submicron-scaled alumina particles, yielding a gradient composite. It was found that the thermal conductivity according to laser flash analysis of a sliced specimen ranged from 0.25 to 0.45 W·m−1·K−1 at room temperature. If the thermal conductivity of an uncut specimen was measured with a guarded heat flow meter, the ‘averaged’ thermal conductivity was measured to be only 0.25 W·m−1·K−1. Finite element analysis revealed that the heat dissipation through a gradient composite was of intermediate speed in comparison with homogeneous composites exhibiting a non-gradient thermal conductivity of 0.25 and 0.45 W·m−1·K−1. Full article
(This article belongs to the Special Issue Polymers: Design, Function and Application)
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Open AccessArticle Functionalization of Molecularly Imprinted Polymer Microspheres for the Highly Selective Removal of Contaminants from Aqueous Solutions and the Analysis of Food-Grade Fish Samples
Polymers 2018, 10(10), 1130; https://doi.org/10.3390/polym10101130
Received: 10 September 2018 / Revised: 9 October 2018 / Accepted: 9 October 2018 / Published: 11 October 2018
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Abstract
The proliferation of pollution in aquatic environments has become a growing concern
and calls for the development of novel adsorbents capable of selectively removing notorious and
recalcitrant pollutants from these ecosystems. Herein, a general strategy was developed for the
synthesis and functionalization of
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The proliferation of pollution in aquatic environments has become a growing concern
and calls for the development of novel adsorbents capable of selectively removing notorious and
recalcitrant pollutants from these ecosystems. Herein, a general strategy was developed for the
synthesis and functionalization of molecularly imprinted polymer microspheres (MIPs) that could
be optimized to possess a significant adsorption selectivity to an organic pollutant in aqueous
media, in addition to a high adsorption capacity. Considering that the molecular imprinting alone
was far from satisfactory to produce a high-performance MIPs-based adsorbent, further structural
engineering and surface functionalization were performed in this study. Although the more carboxyl
groups on the surfaces of the MIPs enhanced the adsorption rate and capacity toward an organic
pollutant through electrostatic interactions, they did not strengthen the adsorption selectivity in a
proportional manner. Through a systematic study, the optimized sample exhibiting both impressive
selectivity and capacity for the adsorption of the organic pollutant was found to possess a small
particle size, a high specific surface area, a large total pore volume, and an appropriate amount of
surface carboxyl groups. While the pseudo-second-order kinetic model was found to better describe
the process of the adsorption onto the surface of MIPs as compared to the pseudo-first-order kinetic
model, neither Langmuir nor Freundlich isothermal model could be used to well fit the isothermal
adsorption data. Increased temperature facilitated the adsorption of the organic pollutant onto the
MIPs, as an endothermic process. Furthermore, the optimized MIPs were also successfully employed
as a stationary phase for the fabrication of a molecularly imprinted solid phase extraction column,
with which purchased food-grade fish samples were effectively examined. Full article
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Open AccessReview In Situ Synthesis of Hybrid Inorganic–Polymer Nanocomposites
Polymers 2018, 10(10), 1129; https://doi.org/10.3390/polym10101129
Received: 14 September 2018 / Revised: 8 October 2018 / Accepted: 9 October 2018 / Published: 11 October 2018
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Abstract
Hybrid inorganic–polymer nanocomposites can be employed in diverse applications due to the potential combination of desired properties from both the organic and inorganic components. The use of novel bottom–up in situ synthesis methods for the fabrication of these nanocomposites is advantageous compared to
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Hybrid inorganic–polymer nanocomposites can be employed in diverse applications due to the potential combination of desired properties from both the organic and inorganic components. The use of novel bottom–up in situ synthesis methods for the fabrication of these nanocomposites is advantageous compared to top–down ex situ mixing methods, as it offers increased control over the structure and properties of the material. In this review, the focus will be on the application of the sol–gel process for the synthesis of inorganic oxide nanoparticles in epoxy and polysiloxane matrices. The effect of the synthesis conditions and the reactants used on the inorganic structures formed, the interactions between the polymer chains and the inorganic nanoparticles, and the resulting properties of the nanocomposites are appraised from several studies over the last two decades. Lastly, alternative in situ techniques and the applications of various polymer–inorganic oxide nanocomposites are briefly discussed. Full article
(This article belongs to the Special Issue Nanoparticle-Reinforced Polymers)
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Open AccessArticle Designing and Preparation of Fiber-Reinforced Composites with Enhanced Interface Adhesion
Polymers 2018, 10(10), 1128; https://doi.org/10.3390/polym10101128
Received: 30 August 2018 / Revised: 30 September 2018 / Accepted: 10 October 2018 / Published: 11 October 2018
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Abstract
The interfacial properties between fibers and resin matrices show great influence on the properties of fiber-reinforced composites. In this work, phthalonitrile containing benzoxazine (BA-ph) was chosen as the resin matrix, which combined with the glass fiber (GF) to prepare reinforced composite laminates at
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The interfacial properties between fibers and resin matrices show great influence on the properties of fiber-reinforced composites. In this work, phthalonitrile containing benzoxazine (BA-ph) was chosen as the resin matrix, which combined with the glass fiber (GF) to prepare reinforced composite laminates at low temperature (200 °C). The poly(arylene ether nitrile) (PEN) was used to modify the GF and BA-ph matrix. Curing behaviors of the BA-ph/PEN were investigated with Differential scanning calorimetric (DSC) and Dynamic rheological analysis (DRA), and results indicated that the polymerization would be hindered by PEN due to the dilution effects. Moreover, the formation of triazine rings which assigning to the ring-forming polymerization of nitrile groups in BA-ph and PEN could improve the compatibility of BA-ph and PEN in the matrix. The SEM images of the fracture surface of the composites revealed that the brittleness of BA-ph matrix and interfacial adhesion between GFs and matrix was improved. The enhanced interfacial adhesion was detailedly discussed from the perspective of physical entanglement and the copolymerization between PEN chains on the surface of GFs and BA-ph/PEN matrix. The results of DMA also explained the toughness of BA-ph/PEN matrix, the semi-interpenetrating polymer networks and the interfacial adhesion. In sum, a feasible strategy that modifies the surface of GFs and the brittleness of the thermosetting matrix by high-performance thermoplastic polymers, which can be employed to prepare the composite laminates with improved properties. Full article
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