Topical Collection "Multifunctional Polymer Nanocomposites"

A topical collection in Polymers (ISSN 2073-4360). This collection belongs to the section "Polymer Physics and Theory".

Editors

Dr. Mohammad Arjmand
E-Mail Website
Guest Editor
School of Engineering, University of British Columbia, Kelowna, BC V1V 1V7, Canada
Interests: nanomaterials synthesis; carbon nanotube; graphene; metal-organic framework; MXene; polymer processing; multifunctional polymer nanocomposites; gas sensors; additive manufacturing/3D printing; wastewater treatment; electromagnetic interference shielding
Special Issues, Collections and Topics in MDPI journals
Dr. Amir Ameli
E-Mail Website
Guest Editor
Advanced Composites Laboratory, School of Mechanical and Materials Engineering, Washington State University, 2710 Crimson Way, Richland, WA 99354, USA
Interests: multifunctional polymer nanocomposites; additive manufacturing/3D Printing; bioproducts; smart materials and structures; advanced polymer-based foams; mechanics of materials
Special Issues, Collections and Topics in MDPI journals

Topical Collection Information

Dear Colleagues,

Polymers offer remarkable physical properties such as their light weight, low cost, easy processability, corrosion resistance, improved design options, etc. These properties distinguish polymers from their traditional rivals such as ceramics and metals. Nonetheless, in order to employ polymers as the next generation of advanced materials for existing and emerging applications, their physical properties must be significantly improved and additional functionalities must be imparted. This can be carried out via incorporating multifunctional nanomaterials into polymer matrices.

Despite the outstanding physical properties of different types of nanomaterials, the full exploitation of their physical properties toward the development of multifunctional polymer nanocomposites is still a challenge, due to their synthesis difficulties, agglomeration, poor affinity toward polymers, complexities in microstructure design and control, nanofiller-polymer processing challenges, etc. This collection aims to address partial or full coverage of the diamond of Synthesis–Processing–Structure–Property toward the development of multifunctional polymer nanocomposites containing various types of nanomaterials. Covering the diamond will generate a platform to achieve a better understanding of the physical properties of polymer nanocomposites and their relationship with nanofiller synthesis, nanofiller structure, nanofiller–polymer processing, and nanocomposite morphology.

Dr. Mohammad Arjmand
Dr. Amir Ameli
Guest Editors

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Related Special Issues

Published Papers (25 papers)

2021

Jump to: 2020, 2019

Article
Waste to Value-Added Product: Developing Electrically Conductive Nanocomposites Using a Non-Recyclable Plastic Waste Containing Vulcanized Rubber
Polymers 2021, 13(15), 2427; https://doi.org/10.3390/polym13152427 - 23 Jul 2021
Viewed by 544
Abstract
This study intends to show the potential application of a non-recyclable plastic waste towards the development of electrically conductive nanocomposites. Herein, the conductive nanofiller and binding matrix are carbon nanotubes (CNT) and polystyrene (PS), respectively, and the waste material is a plastic foam [...] Read more.
This study intends to show the potential application of a non-recyclable plastic waste towards the development of electrically conductive nanocomposites. Herein, the conductive nanofiller and binding matrix are carbon nanotubes (CNT) and polystyrene (PS), respectively, and the waste material is a plastic foam consisting of mainly vulcanized nitrile butadiene rubber and polyvinyl chloride (PVC). Two nanocomposite systems, i.e., PS/Waste/CNT and PS/CNT, with different compositions were melt-blended in a mixer and characterized for electrical properties. Higher electrical conduction and improved electromagnetic interference shielding performance in PS/Waste/CNT system indicated better conductive network of CNTs. For instance, at 1.0 wt.% CNT loading, the PS/Waste/CNT nanocomposites with the plastic waste content of 30 and 50 wt.% conducted electricity 3 and 4 orders of magnitude higher than the PS/CNT nanocomposite, respectively. More importantly, incorporation of the plastic waste (50 wt.%) reduced the electrical percolation threshold by 30% in comparison with the PS/CNT nanocomposite. The enhanced network of CNTs in PS/Waste/CNT samples was attributed to double percolation morphology, evidenced by optical images and rheological tests, caused by the excluded volume effect of the plastic waste. Indeed, due to its high content of vulcanized rubber, the plastic waste did not melt during the blending process. As a result, CNTs concentrated in the PS phase, forming a denser interconnected network in PS/Waste/CNT samples. Full article
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Article
The Influence of Nano CaCO3 on Nucleation and Interface of PP Nano Composite: Matrix Processability and Impact Resistance
Polymers 2021, 13(9), 1389; https://doi.org/10.3390/polym13091389 - 25 Apr 2021
Viewed by 586
Abstract
Polypropylene (PP) is a commodity material that has been increasingly used in different industries in the past two decades due to its versatile properties when enhanced with additives. Homo polypropylene, in general, has weak mechanical properties and limited chemical resistance; thus, using a [...] Read more.
Polypropylene (PP) is a commodity material that has been increasingly used in different industries in the past two decades due to its versatile properties when enhanced with additives. Homo polypropylene, in general, has weak mechanical properties and limited chemical resistance; thus, using a different type of fillers to adjust such properties to fit the required applications opened a large market for this commodity. Understanding the interface constituent between the polymer matrix and the added filler and the nucleation behavior is a key to fine control of the enhancement of PP properties. In this study, PP was incorporated with nano calcium carbonate (CaCO3) at 2 and 5 wt% in the presence of maleic anhydride (MAH) to overcome the weak interface due to low polymer polarity. The mix was compounded in a twin screws extruder at a temperature range of 180–200 °C ; then, the prepared samples were left to dry for 24 h at 25 °C. Nuclear Magnetic Resonance (NMR) was used to study the interface adhesion of the nanofiller and the curved revealed that at 2% of nano CaCO3 PP structure remained the same and the nano experienced good adhesion to the polymer matrix. The mechanical impact resistance results showed a real enhancement to the polymer matrix of the nanocomposite by 37%. Moreover, DSC results showed a faster crystallinity rate due to the nanofiller acting as a nucleating agent and rheology tests indicated that low content of nano additive (2%) has better processability behavior, with suitable viscosity complex values at high frequencies. Full article
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Article
Morphology Evolution, Molecular Simulation, Electrical Properties, and Rheology of Carbon Nanotube/Polypropylene/Polystyrene Blend Nanocomposites: Effect of Molecular Interaction between Styrene-Butadiene Block Copolymer and Carbon Nanotube
Polymers 2021, 13(2), 230; https://doi.org/10.3390/polym13020230 - 11 Jan 2021
Cited by 5 | Viewed by 845
Abstract
This work studied the impact of three types of styrene-butadiene (SB and SBS) block copolymers on the morphology, electrical, and rheological properties of immiscible blends of polypropylene:polystyrene (PP:PS)/multi-walled carbon nanotubes (MWCNT) with a fixed blend ratio of 70:30 vol.%. The addition of block [...] Read more.
This work studied the impact of three types of styrene-butadiene (SB and SBS) block copolymers on the morphology, electrical, and rheological properties of immiscible blends of polypropylene:polystyrene (PP:PS)/multi-walled carbon nanotubes (MWCNT) with a fixed blend ratio of 70:30 vol.%. The addition of block copolymers to PP:PS/MWCNT blend nanocomposites produced a decrease in the droplet size. MWCNTs, known to induce co-continuity in PP:PS blends, did not interfere with the copolymer migration to the interface and, thus, there was morphology refinement upon addition of the copolymers. Interestingly, the addition of the block copolymers decreased the electrical resistivity of the PP:PS/1.0 vol.% MWCNT system by 5 orders of magnitude (i.e., increase in electrical conductivity). This improvement was attributed to PS Droplets-PP-Copolymer-Micelle assemblies, which accumulated MWCNTs, and formed an integrated network for electrical conduction. Molecular simulation and solubility parameters were used to predict the MWCNT localization in the immiscible blend. The simulation results showed that diblock copolymers favorably interact with the nanotubes in comparison to the triblock copolymer, PP, and PS. However, the interaction between the copolymers and PP or PS is stronger than the interaction of the copolymers and MWCNTs. Hence, the addition of copolymer also changed the localization of MWCNT from PS to PS–PP–Micelles–Interface, as observed by TEM images. In addition, in the last step of this work, we investigated the effect of the addition of copolymers on inter- and intra-cycle viscoelastic behavior of the MWCNT incorporated polymer blends. It was found that addition of the copolymers not only affects the linear viscoelasticity (e.g., increase in the value of the storage modulus) but also dramatically impacts the nonlinear viscoelastic behavior under large deformations (e.g., higher distortion of Lissajous–Bowditch plots).] Full article
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2020

Jump to: 2021, 2019

Article
Polyaspartate-Ionene/Na+-Montmorillonite Nanocomposites as Novel Adsorbent for Anionic Dye; Effect of Ionene Structure
Polymers 2020, 12(12), 2843; https://doi.org/10.3390/polym12122843 - 29 Nov 2020
Cited by 1 | Viewed by 505
Abstract
Surface modification of sodium montmorillonite (Na+-Mt) was performed using antimicrobial agents to produce an ecofriendly nanocomposite. The adsorption performance of the nanocomposite has been evaluated for the removal of Acid Blue 25 dye (AB25) as a model organic pollutant from wastewater. [...] Read more.
Surface modification of sodium montmorillonite (Na+-Mt) was performed using antimicrobial agents to produce an ecofriendly nanocomposite. The adsorption performance of the nanocomposite has been evaluated for the removal of Acid Blue 25 dye (AB25) as a model organic pollutant from wastewater. Sodium montmorillonite (Na+-Mt) was modified with three different ionene compounds through ion exchange, and further modified through reaction with polyaspartate to provide three ecofriendly nanocomposites (denoted ICP-1–3). The nanocomposites were characterized using FTIR, PXRD, TEM, SEM, and BET surface area. The adsorption isotherm of AB25 onto ICP-1, ICP-2 and ICP-3 was analyzed using the Langmuir, Freundlich, and Dubinin–Radushkevich (D–R) models. The adsorption isotherm was found to be best fitted by a Freundlich model. The thermodynamic parameters were calculated. The kinetics of the adsorption data were analyzed and the adsorption behavior was found to obey pseudo-second-order kinetics, and the intraparticle diffusion model. The adsorption mechanism was studied by FTIR. Full article
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Article
Influence of Antimony Oxide on Epoxy Based Intumescent Flame Retardation Coating System
Polymers 2020, 12(11), 2721; https://doi.org/10.3390/polym12112721 - 17 Nov 2020
Cited by 1 | Viewed by 561
Abstract
Ethylenediamine modified Ammonium polyphosphate (EDA-MAPP), and Charring-Foaming Agents (CFA) was prepared via a simple chemical approach and further utilizes for the preparation of Epoxy resin based intumescent flame retardation coatings. The ratio belongs to MAPP and CFA was fixed at 2:1 ratio. Comparative [...] Read more.
Ethylenediamine modified Ammonium polyphosphate (EDA-MAPP), and Charring-Foaming Agents (CFA) was prepared via a simple chemical approach and further utilizes for the preparation of Epoxy resin based intumescent flame retardation coatings. The ratio belongs to MAPP and CFA was fixed at 2:1 ratio. Comparative thermo gravimetric analysis TGA study of Modified Ammonium polyphosphate (MAPP) and Ammonium polyphosphate (APP) investigated. Sb2O3 was introduced into flame retardation coating formulation at various amounts to evaluate the synergistic action of Sb2O3 along with flame retardant coating system. The synergistic action of Sb2O3 on flame retardation coating formulation was studied by vertical burning test (UL-94V), thermo gravimetric analysis (TGA), Limited Oxygen Index (LOI), and Fourier Transform Infra-Red spectroscopy (FTIR). The UL-94V results indicated that adding Sb2O3 effectively increased flame retardancy and meets V-0 ratings at each concentration. The TGA results revealed that the amalgamation of Sb2O3 at each concentration effectively increased the thermal stability of the flame retardant coating system. Cone-calorimeter study results that Sb2O3 successfully minimized the combustion parameters like, Peak Heat Release Rate (PHRR), and Total Heat Release (THR). The FTIR result shows that Sb2O3 can react with MAPP and generates the dense-charred layer which prevents the transfer of heat and oxygen. Full article
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Article
Hydrophobic Shape-Memory Biocomposites from Tung-Oil-Based Bioresin and Onion-Skin-Derived Nanocellulose Networks
Polymers 2020, 12(11), 2470; https://doi.org/10.3390/polym12112470 - 25 Oct 2020
Cited by 4 | Viewed by 814
Abstract
The fabrication of smart biocomposites from sustainable resources that could replace today’s petroleum-derived polymer materials is a growing field of research. Here, we report preparation of novel biocomposites using nanocellulose networks extracted from food residue (onion skin) and a vegetable oil-based bioresin. The [...] Read more.
The fabrication of smart biocomposites from sustainable resources that could replace today’s petroleum-derived polymer materials is a growing field of research. Here, we report preparation of novel biocomposites using nanocellulose networks extracted from food residue (onion skin) and a vegetable oil-based bioresin. The resin was synthesized via the Diels-Alder reaction between furfuryl methacrylate and tung oil at various ratios of the components. The onion-skin-extracted cellulose nanofiber and cellulose nanocrystal networks were then impregnated with the resins yielding biocomposites that exhibited improved mechanical strength and higher storage modulus values. The properties of the resins, as well as biocomposites, were affected by the resin compositions. A 190–240-fold increase in mechanical strength was observed in the cellulose nanofiber (CNF) and cellulose nanocrystal (CNC)-reinforced biocomposites with low furfuryl methacrylate content. The biocomposites exhibited interesting shape-memory behavior with 80–96% shape recovery being observed after 7 creep cycles. Full article
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Article
Radiation Processing and Characterization of Some Ethylene-propylene-diene Terpolymer/Butyl (Halobutyl) Rubber/Nanosilica Composites
Polymers 2020, 12(10), 2431; https://doi.org/10.3390/polym12102431 - 21 Oct 2020
Cited by 2 | Viewed by 694
Abstract
Composites based on ethylene–propylene–diene terpolymer (EPDM), butyl/halobutyl rubber and nanosilica were prepared by melt mixing and subjected to different doses of electron beam irradiation. The effect of irradiation dose on the mechanical properties, morphology, glass transition temperature, thermal stability and water uptake [...] Read more.
Composites based on ethylene–propylene–diene terpolymer (EPDM), butyl/halobutyl rubber and nanosilica were prepared by melt mixing and subjected to different doses of electron beam irradiation. The effect of irradiation dose on the mechanical properties, morphology, glass transition temperature, thermal stability and water uptake was investigated. The efficiency of the crosslinking by electron beam irradiation was analyzed by Charlesby–Pinner parameter evaluation and crosslink density measurements. The scanning electron microscopy data showed a good dispersion of nanosilica in the rubber matrix. An improvement in hardness and 100% modulus was revealed by increasing irradiation dose up to 150 kGy. The interaction between polymer matrix and nanosilica was analyzed using the Kraus equation. Additionally, these results indicated that the mechanical properties, surface characteristics, and water uptake were dependent on crosslink characteristics. Full article
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Article
Polyvinyl Alcohol/Calcium Carbonate Nanocomposites as Efficient and Cost-Effective Cationic Dye Adsorbents
Polymers 2020, 12(10), 2179; https://doi.org/10.3390/polym12102179 - 24 Sep 2020
Cited by 2 | Viewed by 1070
Abstract
A novel polyvinyl alcohol (PVA)/calcium carbonate-based double-layer cationic dye adsorbent was developed. Polyvinyl alcohol (50 wt %) and calcium carbonate (50 wt %) were used together with borax as a cross-linking agent. The nanocomposite was prepared using only water, without the need for [...] Read more.
A novel polyvinyl alcohol (PVA)/calcium carbonate-based double-layer cationic dye adsorbent was developed. Polyvinyl alcohol (50 wt %) and calcium carbonate (50 wt %) were used together with borax as a cross-linking agent. The nanocomposite was prepared using only water, without the need for any toxic solvent or hazardous chemical. The final samples were obtained by the solvent casting method. The nanocomposite adsorbent was characterized using a Fourier transform infrared (FTIR) spectroscope and a scanning electron microscope (SEM). The adsorption performance on two cationic dyes, i.e., methylene blue and safranin was studied. Dye adsorption was quantified by measuring the nanocomposite swelling, contact time, and dye concentration. Pseudo first-order and pseudo second-order kinetic models as well as intraparticle diffusion model were used to model the adsorption kinetics. Moreover, the isotherm dye adsorption was investigated by Langmuir and Freundlich models. The results revealed that the developed nanocomposite has relatively high adsorption efficiency and short adsorption time and retains its performance after several successive absorption–desorption processes. The results also showed that the pseudo-second-order model best describes the adsorption kinetics, and the Freundlich isotherm model has a better compatibility with the experimental data. Finally, an adsorption mechanism was proposed for the dye removal process. The developed PVA/CaCO3 nanocomposite can be potentially used for efficient dye removal in wastewater treatments. Full article
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Article
Effect of Alumina Nanowires on the Thermal Conductivity and Electrical Performance of Epoxy Composites
Polymers 2020, 12(9), 2126; https://doi.org/10.3390/polym12092126 - 17 Sep 2020
Cited by 6 | Viewed by 757
Abstract
Alumina nanowires (Al2O3-NWs)/epoxy resin composites have been thoroughly studied due to their excellent insulating and dielectric performance. In particular, understanding the effect of nano-alumina with different morphologies on the dielectric performance of composites is of great significance. In this [...] Read more.
Alumina nanowires (Al2O3-NWs)/epoxy resin composites have been thoroughly studied due to their excellent insulating and dielectric performance. In particular, understanding the effect of nano-alumina with different morphologies on the dielectric performance of composites is of great significance. In this study, Al2O3-NWs with lengths of approximately 100 nm and diameters of approximately 5 nm were prepared and blended with anepoxy resin to form composites, and the effect of the mass fraction of fillers on the thermal conductivity of the composites was investigated. Specifically, the effect of alumina fillers with ananowire structure on the insulating and dielectric performance and breakdown strength of the epoxy composites were analyzed. The influence principle of the interfacial effect and heat accumulation on the dielectric and insulating properties of the composites were described. The results demonstrated that the thermal conductivity of Al2O3-NWs/epoxy resin composites was higher than that of the bare epoxy resin. The thermal conductivity of Al2O3-NWs/epoxy resin composites increased with increasing mass fraction of fillers. When the mass fraction of fillers was 10%, the thermal conductivity of the composite was 134% higher than that of the epoxy resin matrix. The volume resistivity of the composites first increased and then decreased as the mass fraction of fillers increased, while the dielectric constant of the composites increased with increasing mass fraction of fillers and decreasing frequency. The dielectric loss of the composites decreased and then increased as the mass fraction of fillers increased, and it increased with increasing frequency. Additionally, the alternating current breakdown strength of the composites first increased and then decreased withincreasingmass fraction of fillers. Full article
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Article
Effect of a Monomer Composition on the Mechanical Properties and Glass Transition Temperature of a Waterborne Polyurethane/Graphene Oxide and Waterborne Polyurethane/MWCNT Nanocomposite
Polymers 2020, 12(9), 2013; https://doi.org/10.3390/polym12092013 - 03 Sep 2020
Cited by 2 | Viewed by 767
Abstract
Anionic waterborne polyurethane (aWPU) is not compatible with graphene oxide (GO) due to the repulsive force acting on identical ionic charges. In this study, we fabricated cationic surfactant treated GO and cationic surfactant treated carbon nanotube (CNT) to increase the compatibility with aWPU. [...] Read more.
Anionic waterborne polyurethane (aWPU) is not compatible with graphene oxide (GO) due to the repulsive force acting on identical ionic charges. In this study, we fabricated cationic surfactant treated GO and cationic surfactant treated carbon nanotube (CNT) to increase the compatibility with aWPU. Cationic waterborne polyurethane (WPU) and nanocomposites thereof were also prepared. On the basis of the mechanical properties of the nanocomposites, glass transition temperature (Tg), and a stability test, it was found that the compatibility between WPU and a nanofiller (NF) was enhanced to a great extent when WPU and NF had opposite ionicity. The Tg and mechanical properties of WPU increased with the addition of NF, showed the maximum value and thereafter decreased with further addition. The effect of composition of ionic monomer in WPU was also investigated. As the composition of the ionic monomer increases, the concentration of NF for the maximum Tg and mechanical properties increases. This was attributed to the ionic association between the NF and WPU. Full article
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Article
Effects of Carbonyl Iron Powder (CIP) Content on the Electromagnetic Wave Absorption and Mechanical Properties of CIP/ABS Composites
Polymers 2020, 12(8), 1694; https://doi.org/10.3390/polym12081694 - 29 Jul 2020
Cited by 3 | Viewed by 880
Abstract
Three-dimensional (3D) printing technology has proven to be a convenient and effective method to fabricate structural electromagnetic wave (EMW) absorbers with tunable EMW absorption properties. To obtain a functional material with strong EMW absorbing performance and excellent mechanical properties for fused deposition modeling [...] Read more.
Three-dimensional (3D) printing technology has proven to be a convenient and effective method to fabricate structural electromagnetic wave (EMW) absorbers with tunable EMW absorption properties. To obtain a functional material with strong EMW absorbing performance and excellent mechanical properties for fused deposition modeling (FDM) 3D printing technology, in this work, carbonyl iron powder (CIP)/acrylonitrile-butadiene-styrene copolymer (ABS) composites with different CIP contents were prepared by the melt-mixing process. The effects of the CIP content on the EMW absorption and mechanical properties of CIP/ABS composites were investigated. The CIP/ABS composite with a CIP content of 40 wt.% presented the lowest reflection loss (RL) of −48.71 dB for the optimal impedance matching. In addition, this composite exhibited optimal mechanical properties due to the good dispersion of the CIPs in the matrix ABS. Not only were the tensile and flexural strength similar to pure ABS, but the tensile and flexural modulus were 32% and 37% higher than those of pure ABS, respectively. With a CIP content of 40 wt.%, the CIP/ABS composite proved to be a novel functional material with excellent EMW absorbing and mechanical properties, providing great potential for the development of structural absorbers via FDM 3D printing technology. Full article
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Article
Targeting Delivery System for Lactobacillus Plantarum Based on Functionalized Electrospun Nanofibers
Polymers 2020, 12(7), 1565; https://doi.org/10.3390/polym12071565 - 15 Jul 2020
Cited by 7 | Viewed by 1019
Abstract
With the increased interest in information on gut microbes, people are realizing the benefits of probiotics to health, and new technologies to improve the viability of probiotics are still explored. However, most probiotics have poor resistance to adverse environments. In order to improve [...] Read more.
With the increased interest in information on gut microbes, people are realizing the benefits of probiotics to health, and new technologies to improve the viability of probiotics are still explored. However, most probiotics have poor resistance to adverse environments. In order to improve the viability of lactic acid bacteria, polylactic acid (PLA) nanofibers were prepared by coaxial electrospinning. The electrospinning voltage was 16 kV, and the distance between spinneret and collector was 15 cm. The feed rates of the shell and core solutions were 1.0 and 0.25 mL/h, respectively. The lactic acid bacteria were encapsulated in the coaxial electrospun nanofibers with PLA and fructooligosaccharides (FOS) as the shell materials. Scanning electron microscopy, transmission electron microscopy, and laser scanning confocal microscopy showed that lactic acid bacteria were encapsulated in the coaxial electrospun nanofibers successfully. The water contact angle test indicated that coaxial electrospun nanofiber films had good hydrophobicity. An in vitro simulated digestion test exhibited that the survival rate of lactic acid bacteria encapsulated in coaxial electrospun nanofiber films was more than 72%. This study proved that the viability of probiotics can be improved through encapsulation within coaxial electrospun PLA nanofibers and provided a novel approach for encapsulating bioactive substances. Full article
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Article
Superior X-ray Radiation Shielding Effectiveness of Biocompatible Polyaniline Reinforced with Hybrid Graphene Oxide-Iron Tungsten Nitride Flakes
Polymers 2020, 12(6), 1407; https://doi.org/10.3390/polym12061407 - 23 Jun 2020
Cited by 8 | Viewed by 1155
Abstract
X-ray radiation is a harmful carcinogenic electromagnetic source that can adversely affect the health of living species and deteriorate the DNA of cells, thus it’s vital to protect vulnerable sources from them. To address this flaw, the conductive polymeric structure of polyaniline (PANi) [...] Read more.
X-ray radiation is a harmful carcinogenic electromagnetic source that can adversely affect the health of living species and deteriorate the DNA of cells, thus it’s vital to protect vulnerable sources from them. To address this flaw, the conductive polymeric structure of polyaniline (PANi) was reinforced with diverse filler loadings (i.e., 25 wt % and 50 wt %) of hybrid graphene oxide-iron tungsten nitride (ITN) flakes toward attenuation of X-ray beams and inhabitation of microorganisms’ growth. Primary characterizations confirmed the successful decoration of graphene oxide (GO) with interconnected and highly dense structure of iron tungsten nitride with a density of about 24.21 g·cm−3 and reinforcement of PANi with GO-ITN. Additionally, the outcome of evaluations showed the superior performance of developed shields, where a shield with 1.2 mm thickness containing 50 wt % GO-ITN showed 131.73% increase in the electrical conductivity (compared with neat PANi) along with 78.07%, 57.12%, and 44.99% decrease in the amplitude of the total irradiated X-ray waves at 30, 40, and 60 kVp tube voltages, respectively, compared with control X-ray dosage. More importantly, the developed shields not only showed non-toxic nature and improved the viability of cells, but also completely removed the selected microorganisms at a concentration of 1000 µg·mL−1. Full article
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Article
Dental Sealant Empowered by 1,3,5-Tri Acryloyl Hexahydro-1,3,5-Triazine and α-Tricalcium Phosphate for Anti-Caries Application
Polymers 2020, 12(4), 895; https://doi.org/10.3390/polym12040895 - 12 Apr 2020
Cited by 4 | Viewed by 1249
Abstract
: Quaternary ammonium compounds and calcium phosphates have been incorporated into dental materials to enhance their biointeractivity and preventive effects. This study aimed at evaluating the physical and chemical properties and effects against Streptococcus mutans of a dental sealant containing 1,3,5-tri acryloyl hexahydro-1,3,5-triazine [...] Read more.
: Quaternary ammonium compounds and calcium phosphates have been incorporated into dental materials to enhance their biointeractivity and preventive effects. This study aimed at evaluating the physical and chemical properties and effects against Streptococcus mutans of a dental sealant containing 1,3,5-tri acryloyl hexahydro-1,3,5-triazine (TAT) and α-tricalcium phosphate (α‐TCP). A methacrylate-based dental sealant was initially formulated. α‐TCP and TAT (Gα-TCPTAT) were added to the experimental sealant at 2 wt.% each. One group was formulated without α‐TCP and TAT and used as control (GCTRL). All tested resins were analyzed for polymerization kinetics and degree of conversion (DC %), Knoop hardness (KHN), softening in solvent (∆KHN%), ultimate tensile strength (UTS), the contact angle with water or with α-bromonaphthalene, surface free energy (SFE) and antibacterial activity against Streptococcus mutans in biofilm and in planktonic cells. The polymerization kinetic was different between groups, but without statistical differences in the DC % (p<0.05). KHN and ΔKHN% did not change between groups (p>0.05), but Gα-TCPTAT presented greater UTS compared to GCTRL (p<0.05). No differences were found for contact angle (p>0.05) or SFE (p>0.05). Gα-TCPTAT showed greater antibacterial activity in comparison to GCTRL (p<0.05). The formulation of dental sealants containing TAT and α-TCP can be characterized by improved mechanical and antibacterial properties. Full article
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Article
A Novel Zirconium Modified Arylacetylene Resin: Preparation, Thermal Properties and Ceramifiable Mechanism
Polymers 2020, 12(3), 684; https://doi.org/10.3390/polym12030684 - 19 Mar 2020
Cited by 2 | Viewed by 851
Abstract
With the rapid development of thermal protection systems for the aerospace industry and power electronics, polyarylacetylene (PAA) resin plays an important role because of its good mechanical properties, high glass transition temperature (Tg), low water absorption, high char yield (Yc [...] Read more.
With the rapid development of thermal protection systems for the aerospace industry and power electronics, polyarylacetylene (PAA) resin plays an important role because of its good mechanical properties, high glass transition temperature (Tg), low water absorption, high char yield (Yc), and the fact that there is no byproduct released in the curing process. In order to further improve the thermal property of PAA based FRP for the thermal protection field, the introduction of a zirconium element into arylacetylene is promising. In this paper, zirconium modified arylacetylene (ZAA) resin was prepared by two-step synthesis. The FTIR analysis characterized its molecular structure and confirmed the products. The viscosity of ZAA was about 6.5 Pa·s when the temperature was above 120 °C. The DSC analysis showed that the ZAA had a low curing temperature, and its apparent activation energy was 103.86 kJ/mol in the Kissinger method and 106.46 kJ/mol in the Ozawa method. The dielectric constant at 1 MHz of poly(zirconium modified arylacetylene) (PZAA) was 3.4. The TG analysis showed that the temperatures of a weight loss of 5% (Td5) and char yield (Yc) at 800 °C of PZAA were 407.5 °C and 61.4%, respectively. The XRD results showed the presence of SiO2 and ZrO2 in the PZAA residue after ablation. The XRF results showed that the contents of SiO2 and ZrO2 in PZAA residual after ablation were, respectively, 15.3% and 12.4%. The SEM showed that the surface of PZAA after ablation had been covered with a dense and rigid ceramic phase composed of ZrO2 and SiO2. Therefore, the introduction of Zr into arylacetylene greatly improved the densification of the surface after ablation, and improved the heat resistant property. Full article
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Article
Effects of Zirconium Silicide on the Vulcanization, Mechanical and Ablation Resistance Properties of Ceramifiable Silicone Rubber Composites
Polymers 2020, 12(2), 496; https://doi.org/10.3390/polym12020496 - 24 Feb 2020
Cited by 11 | Viewed by 1167
Abstract
Ceramifiable silicone rubber composites play important roles in the field of thermal protection systems (TPS) for rocket motor cases due to their advantages. Ceramifiable silicone rubber composites filled with different contents of ZrSi2 were prepared in this paper. The fffects of ZrSi [...] Read more.
Ceramifiable silicone rubber composites play important roles in the field of thermal protection systems (TPS) for rocket motor cases due to their advantages. Ceramifiable silicone rubber composites filled with different contents of ZrSi2 were prepared in this paper. The fffects of ZrSi2 on the vulcanization, mechanical and ablation resistance properties of the composites were also investigated. The results showed that the introduction of ZrSi2 decreased the vulcanization time of silicone rubber. FTIR spectra showed that ZrSi2 did not participate in reactions of the functional groups of silicone rubber. With the increasing content of ZrSi2, the tensile strength increased first and then decreased. The elongation at break decreased and the permanent deformation increased gradually. The thermal conductivity of the composite increased from 0.553 W/(m·K) to 0.694 W/(m·K) as the content of the ZrSi2 increased from 0 to 40 phr. In addition, the thermal conductivity of the composite decreased with the increase of temperature. Moreover, thermal analysis showed that the addition of ZrSi2 increased the initial decomposition temperature of the composite, but had little effect on the peak decomposition temperature in nitrogen. However, the thermal decomposition temperature of the composite in air was lower than that in nitrogen. The addition of ZrSi2 decreased the linear and mass ablation rate, which improved the ablative resistance of the composite. With the ZrSi2 content of 30 phr, the linear and mass ablation rate were 0.041 mm/s and 0.029 g/s, decreasing by 57.5% and 46.3% compared with the composite without ZrSi2, respectively. Consequently, the ceramifiable silicone rubber composite filled with ZrSi2 is very promising for TPS. Full article
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Article
Surface Modification Design for Improving the Strength and Water Vapor Permeability of Waterborne Polymer/SiO2 Composites: Molecular Simulation and Experimental Analyses
Polymers 2020, 12(1), 170; https://doi.org/10.3390/polym12010170 - 09 Jan 2020
Cited by 5 | Viewed by 1561
Abstract
Polymer-based nanocomposites properties are greatly affected by interfacial interaction. Polyacrylate nanocomposites have been widely studied, but few studies have been conducted on their interface mechanism. Therefore, there was an urgent demand for providing a thorough understanding of the polymethyl acrylate/SiO2 (PMA/SiO2 [...] Read more.
Polymer-based nanocomposites properties are greatly affected by interfacial interaction. Polyacrylate nanocomposites have been widely studied, but few studies have been conducted on their interface mechanism. Therefore, there was an urgent demand for providing a thorough understanding of the polymethyl acrylate/SiO2 (PMA/SiO2) nanocomposites to obtain the desired macro-performance. In this paper, a methodology, which combined molecular dynamics simulation with experimental researches, was established to expound the effect of the surface structure of SiO2 particles which were treated with KH550, KH560 or KH570 (KH550-SiO2, KH560-SiO2 and KH570-SiO2) on the mechanical characteristic and water vapor permeability of polymethyl acrylate/SiO2 nanocomposites. The polymethyl acrylate/SiO2 nanocomposites were analyzed in binding energy and mean square displacement. The results indicate that PMA/KH570-SiO2 had the highest tensile strength, while PMA/KH550-SiO2 had the highest elongation at break at the same filler content; KH550-SiO2 spheres can significantly improve water vapor permeability of polyacrylate film. Full article
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2019

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Article
Improved Processing and Properties for Polyphenylene Oxide Modified by Diallyl Orthophthalate Prepolymer
Polymers 2019, 11(12), 2016; https://doi.org/10.3390/polym11122016 - 05 Dec 2019
Viewed by 1016
Abstract
Diallyl orthophthalate (DAOP) prepolymer was investigated as a reactive plasticizer to improve the processability of thermoplastics. The rheology of blends of DAOP prepolymer initiated by 2,3-dimethyl-2,3-diphenylbutane (DMDPB) and polyphenylene oxide (PPO) was monitored during the curing process, and their thermal properties and morphology [...] Read more.
Diallyl orthophthalate (DAOP) prepolymer was investigated as a reactive plasticizer to improve the processability of thermoplastics. The rheology of blends of DAOP prepolymer initiated by 2,3-dimethyl-2,3-diphenylbutane (DMDPB) and polyphenylene oxide (PPO) was monitored during the curing process, and their thermal properties and morphology in separated phases were also studied. Differential scanning calorimetry (DSC) results showed that the cure degree of the reactively plasticized DAOP prepolymer was reduced with increasing PPO due to the dilution effect. The increasing amount of the DAOP prepolymer led to a gradual decrease in the viscosity of the blends and the rheology behavior was consistent with the chemical gelation of DAOP prepolymer in blends. This indicated that the addition of the DAOP prepolymer effectively improved processability. The phase separation occurring during curing of the blend and the transition from the static to dynamic mode significantly influences the development of the morphology of the blend corresponding to limited evolution of the conversion around the gel point. Full article
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Article
Investigation on Plugging and Profile Control of Polymer Microspheres as a Displacement Fluid in Enhanced Oil Recovery
Polymers 2019, 11(12), 1993; https://doi.org/10.3390/polym11121993 - 02 Dec 2019
Cited by 8 | Viewed by 1044
Abstract
Polymer microspheres (PMs) are used as a new material to recover residual oil left in unswept oil areas after secondary recovery methods. The fact that the PMs plug the macropores causes the flow direction of the injection fluid to be transferred from macropores [...] Read more.
Polymer microspheres (PMs) are used as a new material to recover residual oil left in unswept oil areas after secondary recovery methods. The fact that the PMs plug the macropores causes the flow direction of the injection fluid to be transferred from macropores to micropores. In order to investigate the plugging and profile control mechanisms of PMs in reservoirs, four kinds of PMs with different particle sizes and four kinds of artificial cores with different permeability were selected for flooding tests, including plugging experiments and profile control experiments. The pore throat size distribution of cores was characterized by nuclear magnetic resonance (NMR) technology. The particle size distribution of PMs used in the experiment was characterized using a laser particle size analyzer. The results showed that there are six matching relationships existing simultaneously between pore throats and PMs based on theoretical analysis, which are completely plugging, single plugging, bridge plugging, smooth passing, deposition, and deformable passing. A key principle for optimizing PMs in profile control is that the particle size of the selected PMs can enter the high permeability layer well, but it is difficult for it to enter the low permeability layer. The results of this paper provide a theoretical basis for the optimal particle size of PMs during the oil field profile control process. Full article
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Article
Nanofiller Dispersion, Morphology, Mechanical Behavior, and Electrical Properties of Nanostructured Styrene-Butadiene-Based Triblock Copolymer/CNT Composites
Polymers 2019, 11(11), 1831; https://doi.org/10.3390/polym11111831 - 07 Nov 2019
Cited by 4 | Viewed by 1302
Abstract
A nanostructured linear triblock copolymer based on styrene and butadiene with lamellar morphology is filled with multiwalled carbon nanotubes (MWCNTs) of up to 1 wt% by melt compounding. This study deals with the dispersability of the MWCNTs within the nanostructured matrix and its [...] Read more.
A nanostructured linear triblock copolymer based on styrene and butadiene with lamellar morphology is filled with multiwalled carbon nanotubes (MWCNTs) of up to 1 wt% by melt compounding. This study deals with the dispersability of the MWCNTs within the nanostructured matrix and its consequent impact on block copolymer (BCP) morphology, deformation behavior, and the electrical conductivity of composites. By adjusting the processing parameters during melt mixing, the dispersion of the MWCNTs within the BCP matrix are optimized. In this study, the morphology and glass transition temperatures (Tg) of the hard and soft phase are not significantly influenced by the incorporation of MWCNTs. However, processing-induced orientation effects of the BCP structure are reduced by the addition of MWCNT accompanied by a decrease in lamella size. The stress-strain behavior of the triblock copolymer/MWCNT composites indicate higher Young’s modulus and pronounced yield point while retaining high ductility (strain at break ~ 400%). At a MWCNT content of 1 wt%, the nanocomposites are electrically conductive, exhibiting a volume resistivity below 3 × 103 Ω·cm. Accordingly, the study offers approaches for the development of mechanically flexible functional materials while maintaining a remarkable structural property profile. Full article
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Article
Adsorption of Pb2+ from Aqueous Solutions Using Novel Functionalized Corncobs via Atom Transfer Radical Polymerization
Polymers 2019, 11(10), 1715; https://doi.org/10.3390/polym11101715 - 19 Oct 2019
Cited by 7 | Viewed by 916
Abstract
The present study developed novel functionalized corncobs introducing brushes with dense and active carboxyl groups (–COOH), named MC-g-PAA, for the highly efficient adsorption of Pb2+ from aqueous solutions. MC-g-PAA were synthesized via atom transfer radical polymerization (ATRP) and characterized by Fourier transform [...] Read more.
The present study developed novel functionalized corncobs introducing brushes with dense and active carboxyl groups (–COOH), named MC-g-PAA, for the highly efficient adsorption of Pb2+ from aqueous solutions. MC-g-PAA were synthesized via atom transfer radical polymerization (ATRP) and characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The amount of Pb2+ adsorbed on MC-g-PAA by hydrolysis with t-BuOK was 2.28 times greater than that with NaOH, attributed to the larger steric effect of t-BuOK, which reduced the hydrolysis of the bromo-ester groups. The influence of different parameters including the solid/liquid ratio, working solution pH, sorption temperature, and initial concentration and sorption time on the adsorption of Pb2+ were investigated in detail in batch experiments. Thermodynamic studies have shown that the adsorption process was spontaneous, endothermic, and accompanied by an increase in randomness. A better fit for the isotherm data was obtained using the Langmuir model than for the other four models and the maximum amount ( q max ) of Pb2+ adsorbed on MC-g-PAA was 342.47 mg/g, which is 21.11 times greater when compared with that of pristine corncobs (16.22 mg/g). The adsorption of Pb2+ on MC-g-PAA was very fast and followed the pseudo-second-order kinetic equation with a correlation coefficient of 0.99999. This monolayer adsorption process was dominated by chemical adsorption, and may proceed according to complexation and electrostatic interactions between Pb2+ and the carboxylate groups. This study indicated that MC-g-PAA could be successfully used as an adsorbent for the removal of Pb2+ from aqueous solutions due to its excellent efficiency. Full article
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Article
Selective Localization of Carbon Black in Bio-Based Poly (Lactic Acid)/Recycled High-Density Polyethylene Co-Continuous Blends to Design Electrical Conductive Composites with a Low Percolation Threshold
Polymers 2019, 11(10), 1583; https://doi.org/10.3390/polym11101583 - 27 Sep 2019
Cited by 8 | Viewed by 1067
Abstract
The electrically conductive poly (lactic acid) (PLA)/recycled high-density polyethylene (HDPE)/carbon black (CB) composites with a fine co-continuous micro structure and selective localization of CB in the HDPE component were fabricated by one-step melt processing via a twin-screw extruder. Micromorphology analysis, electrical conductivity, thermal [...] Read more.
The electrically conductive poly (lactic acid) (PLA)/recycled high-density polyethylene (HDPE)/carbon black (CB) composites with a fine co-continuous micro structure and selective localization of CB in the HDPE component were fabricated by one-step melt processing via a twin-screw extruder. Micromorphology analysis, electrical conductivity, thermal properties, thermal stability, and mechanical properties were investigated. Scanning electron microscope (SEM) images indicate that a co-continuous morphology is formed, and CB is selectively distributed in the HDPE component. With the introduction of CB, the phase size of the PLA component and the HDPE component in PLA/HDPE blends is reduced. In addition, differential scanning calorimetry (DSC) and thermos gravimetric analysis (TGA) results show that the introduction of CB promotes the crystallization behavior of the PLA and HDPE components, respectively, and improves the thermal stability of PLA70/30HDPE/CB composites. The electrically conductive percolation threshold of the PLA70/30HDPE/CB composites is around 5.0 wt %, and the electrical conductivity of PLA70/30HDPE/CB composites reaches 1.0 s/cm and 15 s/cm just at the 10 wt % and 15 wt % CB loading, respectively. Further, the tensile and impact tests show that the PLA70/30HDPE/CB composites have good mechanical properties. The excellent electrical conductivity and good mechanical properties offer the potential to broaden the application of PLA/HDPE/CB composites. Full article
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Article
Tensile and Interfacial Loading Characteristics of Boron Nitride-Carbon Nanosheet Reinforced Polymer Nanocomposites
Polymers 2019, 11(6), 1075; https://doi.org/10.3390/polym11061075 - 21 Jun 2019
Cited by 9 | Viewed by 1552
Abstract
The discovery of hybrid boron nitride–carbon (BN–C) nanostructures has triggered enormous research interest in the design and fabrication of new generation nanocomposites. The robust design of these nanocomposites for target applications requires their mechanical strength to be characterized with a wide range of [...] Read more.
The discovery of hybrid boron nitride–carbon (BN–C) nanostructures has triggered enormous research interest in the design and fabrication of new generation nanocomposites. The robust design of these nanocomposites for target applications requires their mechanical strength to be characterized with a wide range of factors. This article presents a comprehensive study, with the aid of molecular dynamics analysis, of the tensile loading mechanics of BN–C nanosheet reinforced polyethylene (PE) nanocomposites. It is observed that the geometry and lattice arrangement of the BN–C nanosheet influences the tensile loading characteristics of the nanocomposites. Furthermore, defects in the nanosheet can severely impact the tensile loading resistance, the extent of which is determined by the defect’s location. This study also found that the tensile loading resistance of nanocomposites tends to weaken at elevated temperatures. The interfacial mechanics of the BN–C nanocomposites are also investigated. This analysis revealed a strong dependency with the carbon concentration in the BN–C nanosheet. Full article
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Article
Thermal Conductivity and Electrical Resistivity of Melt-Mixed Polypropylene Composites Containing Mixtures of Carbon-Based Fillers
Polymers 2019, 11(6), 1073; https://doi.org/10.3390/polym11061073 - 21 Jun 2019
Cited by 22 | Viewed by 1732
Abstract
Melt-mixed composites based on polypropylene (PP) with various carbon-based fillers were investigated with regard to their thermal conductivity and electrical resistivity. The composites were filled with up to three fillers by selecting combinations of graphite nanoplatelets (GNP), carbon fibers (CF), carbon nanotubes (CNT), [...] Read more.
Melt-mixed composites based on polypropylene (PP) with various carbon-based fillers were investigated with regard to their thermal conductivity and electrical resistivity. The composites were filled with up to three fillers by selecting combinations of graphite nanoplatelets (GNP), carbon fibers (CF), carbon nanotubes (CNT), carbon black (CB), and graphite (G) at a constant filler content of 7.5 vol%. The thermal conductivity of PP (0.26 W/(m·K)) improved most using graphite nanoplatelets, whereas electrical resistivity was the lowest when using multiwalled CNT. Synergistic effects could be observed for different filler combinations. The PP composite, which contains a mixture of GNP, CNT, and highly structured CB, simultaneously had high thermal conductivity (0.5 W/(m·K)) and the lowest electrical volume resistivity (4 Ohm·cm). Full article
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Article
Carbon Nanotube versus Graphene Nanoribbon: Impact of Nanofiller Geometry on Electromagnetic Interference Shielding of Polyvinylidene Fluoride Nanocomposites
Polymers 2019, 11(6), 1064; https://doi.org/10.3390/polym11061064 - 20 Jun 2019
Cited by 11 | Viewed by 1635
Abstract
The similar molecular structure but different geometries of the carbon nanotube (CNT) and graphene nanoribbon (GNR) create a genuine opportunity to assess the impact of nanofiller geometry (tube vs. ribbon) on the electromagnetic interference (EMI) shielding of polymer nanocomposites. In this regard, GNR [...] Read more.
The similar molecular structure but different geometries of the carbon nanotube (CNT) and graphene nanoribbon (GNR) create a genuine opportunity to assess the impact of nanofiller geometry (tube vs. ribbon) on the electromagnetic interference (EMI) shielding of polymer nanocomposites. In this regard, GNR and its parent CNT were melt mixed with a polyvinylidene fluoride (PVDF) matrix using a miniature melt mixer at various nanofiller loadings, i.e., 0.3, 0.5, 1.0 and 2.0 wt%, and then compression molded. Molecular simulations showed that CNT would have a better interaction with the PVDF matrix in any configuration. Rheological results validated that CNTs feature a far stronger network (mechanical interlocking) than GNRs. Despite lower powder conductivity and a comparable dispersion state, it was interestingly observed that CNT nanocomposites indicated a highly superior electrical conductivity and EMI shielding at higher nanofiller loadings. For instance, at 2.0 wt%, CNT/PVDF nanocomposites showed an electrical conductivity of 0.77 S·m−1 and an EMI shielding effectiveness of 11.60 dB, which are eight orders of magnitude and twofold higher than their GNR counterparts, respectively. This observation was attributed to their superior conductive network formation and the interlocking ability of the tubular nanostructure to the ribbon-like nanostructure, verified by molecular simulations and rheological assays. Full article
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