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Polymers, Volume 5, Issue 1 (March 2013) – 16 articles , Pages 1-327

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1164 KiB  
Review
Pressure Retarded Osmosis and Forward Osmosis Membranes: Materials and Methods
by Inger Lise Alsvik and May-Britt Hägg
Polymers 2013, 5(1), 303-327; https://doi.org/10.3390/polym5010303 - 21 Mar 2013
Cited by 195 | Viewed by 30453
Abstract
In the past four decades, membrane development has occurred based on the demand in pressure driven processes. However, in the last decade, the interest in osmotically driven processes, such as forward osmosis (FO) and pressure retarded osmosis (PRO), has increased. The preparation of [...] Read more.
In the past four decades, membrane development has occurred based on the demand in pressure driven processes. However, in the last decade, the interest in osmotically driven processes, such as forward osmosis (FO) and pressure retarded osmosis (PRO), has increased. The preparation of customized membranes is essential for the development of these technologies. Recently, several very promising membrane preparation methods for FO/PRO applications have emerged. Preparation of thin film composite (TFC) membranes with a customized polysulfone (PSf) support, electorspun support, TFC membranes on hydrophilic support and hollow fiber membranes have been reported for FO/PRO applications. These novel methods allow the use of other materials than the traditional asymmetric cellulose acetate (CA) membranes and TFC polyamide/polysulfone membranes. This review provides an outline of the membrane requirements for FO/PRO and the new methods and materials in membrane preparation. Full article
(This article belongs to the Special Issue Polymer Thin Films and Membranes 2013)
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2127 KiB  
Article
Immobilization of Poly(1,1-dimethysilacyclobutane) by Means of Anionic Ring-Opening Polymerization on Organic Nanoparticles and Reinvestigation of Crystallization
by Markus Gallei, Junyu Li, Johannes Elbert, Markus Mazurowski, Astrid Schönberger, Christian Schmidt, Bernd Stühn and Matthias Rehahn
Polymers 2013, 5(1), 284-302; https://doi.org/10.3390/polym5010284 - 15 Mar 2013
Cited by 11 | Viewed by 8904
Abstract
In the present study, the synthesis of poly(1,1-dimethylsilacyclobutane) (PDMSB) by anionic ring opening polymerization (ROP) is reinvestigated, leading to narrowly distributed molar masses (polydispersities 1.04–1.15) in the range of 2.3 to 60 kg mol−1. Investigations of thermal behavior for low molar [...] Read more.
In the present study, the synthesis of poly(1,1-dimethylsilacyclobutane) (PDMSB) by anionic ring opening polymerization (ROP) is reinvestigated, leading to narrowly distributed molar masses (polydispersities 1.04–1.15) in the range of 2.3 to 60 kg mol−1. Investigations of thermal behavior for low molar mass PDMSB revealed an untypical multiple peaks melting phenomenon, which at first glance, seems to be of the same origin as low molar mass poly(ethylene oxide)s. Small angle X-ray scattering (SAXS) and X-ray diffraction (XRD) measurements are done, proving the fast crystallization and subsequent recrystallization for investigated low molar mass samples. Synthetic attempts are expanded to the surface-initiated anionic ROP of 1,1-dimethylsilacyclobutane (DMSB) monomer from the surface of cross-linked polystyrene (PS) nanoparticles. Novel polycarbosilanes (PCS)/organic core/shell particles are obtained, which are investigated by using transmission electron microscopy (TEM) and dynamic light scattering (DLS) experiments. First insights into the crystallization behavior of surface-attached PDMSB chains reveal that crystallization seems to be hindered. Full article
(This article belongs to the Special Issue Ring-Opening Polymerization)
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2267 KiB  
Article
Charge-Transfer Complexes Studied by Dynamic Force Spectroscopy
by Alberto Gomez-Casado, Arántzazu Gonzalez-Campo, Yiheng Zhang, Xi Zhang, Pascal Jonkheijm and Jurriaan Huskens
Polymers 2013, 5(1), 269-283; https://doi.org/10.3390/polym5010269 - 6 Mar 2013
Cited by 4 | Viewed by 9075
Abstract
In this paper, the strength and kinetics of two charge-transfer complexes, naphthol-methylviologen and pyrene-methylviologen, are studied using dynamic force spectroscopy. The dissociation rates indicate an enhanced stability of the pyrene-methylviologen complex, which agrees with its higher thermodynamic stability compared to naphthol-methylviologen complex. [...] Read more.
In this paper, the strength and kinetics of two charge-transfer complexes, naphthol-methylviologen and pyrene-methylviologen, are studied using dynamic force spectroscopy. The dissociation rates indicate an enhanced stability of the pyrene-methylviologen complex, which agrees with its higher thermodynamic stability compared to naphthol-methylviologen complex. Full article
(This article belongs to the Special Issue Supramolecular Chemistry and Self-Assembly 2013)
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364 KiB  
Review
Application of Chondroitin Sulfate Derivatives for Understanding Axonal Guidance in the Nervous System during Development
by Hiroyuki Ichijo, Nobuo Sugiura and Koji Kimata
Polymers 2013, 5(1), 254-268; https://doi.org/10.3390/polym5010254 - 25 Feb 2013
Cited by 5 | Viewed by 7805
Abstract
Neuronal axons and their growth cones recognize molecular guidance cues within the local environment, forming axonal pathways to produce precise neuronal networks during nervous system development. Chondroitin sulfates (CS), carbohydrate chains on chondroitin sulfate proteoglycans, exhibit great structural diversity and exert various influences [...] Read more.
Neuronal axons and their growth cones recognize molecular guidance cues within the local environment, forming axonal pathways to produce precise neuronal networks during nervous system development. Chondroitin sulfates (CS), carbohydrate chains on chondroitin sulfate proteoglycans, exhibit great structural diversity and exert various influences on axons and growth cones as guidance cues or their modulators; however, the relationship between their structural diversity and function in axonal guidance is not well known. To uncover the roles of CS in axonal guidance, artificially modified hybrid molecules: CS derivatives of biotinylated CS and lipid-derivatized CS, were used. The experiments with biotinylated CS suggest that the growing axons act on their environment, modifying CS, and rendering it more favorable for their growth. The experiments with lipid-derivatized CS demonstrated that growth cones distinguish types of CS with different unit contents and are likely to discriminate the structural diversity of CS. The application of CS derivatives is useful in uncovering axon–environment interaction and structure–function relationship of CS directly. Full article
(This article belongs to the Special Issue Bioconjugates/Biohybrid Polymers)
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950 KiB  
Article
Controlled Release of Damascone from Poly(styrene-co-maleic anhydride)-based Bioconjugates in Functional Perfumery
by Damien L. Berthier, Nicolas Paret, Alain Trachsel, Wolfgang Fieber and Andreas Herrmann
Polymers 2013, 5(1), 234-253; https://doi.org/10.3390/polym5010234 - 22 Feb 2013
Cited by 12 | Viewed by 11958
Abstract
Poly(styrene-co-maleic anhydride)s were modified with poly(propylene oxide (PO)-co-ethylene oxide (EO)) side chains (Jeffamine®) with different EO/PO molar ratios, varying between 0.11 and 3.60. These copolymers were then further functionalized with a β-mercapto ketone of δ-damascone. [...] Read more.
Poly(styrene-co-maleic anhydride)s were modified with poly(propylene oxide (PO)-co-ethylene oxide (EO)) side chains (Jeffamine®) with different EO/PO molar ratios, varying between 0.11 and 3.60. These copolymers were then further functionalized with a β-mercapto ketone of δ-damascone. The obtained poly(maleic acid monoamide)-based β-mercapto ketones were then studied as delivery systems for the controlled release of δ-damascone by retro 1,4-addition. The release of δ-damascone, a volatile, bioactive molecule of the family of rose ketones, was studied by dynamic headspace analysis above a cotton surface after deposition of a cationic surfactant containing fabric softening formulation, as a function of the ethylene oxide (EO)/propylene oxide (PO) molar ratio of the grafted copolymer side chains. The polarity of the EO/PO side chain influenced the release efficiency of the damascone in a typical fabric softening application. PO-rich copolymers and the corresponding poly(styrene-co-maleic anhydride) without Jeffamine® side chains were found to be less efficient for the desired fragrance release than the corresponding bioconjugate with a EO/PO ratio of 3.60 in the side chain. This copolymer conjugate seemed to represent a suitable balance between hydrophilicity and hydrophobicity to favor the release of the δ-damascone and to improve the deposition of the conjugate from an aqueous environment onto a cotton surface. Full article
(This article belongs to the Special Issue Bioconjugates/Biohybrid Polymers)
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89 KiB  
New Book Received
Handbook of Polymers. By George Wypych, ChemTec Publishing, 2012; 680 Pages. Price $395.00, ISBN 978-1-895198-47-8
by Shu-Kun Lin
Polymers 2013, 5(1), 225-233; https://doi.org/10.3390/polym5010225 - 20 Feb 2013
Cited by 5 | Viewed by 10712
Abstract
Polymers selected for this edition of the Handbook of Polymers include all major polymeric materials used by the plastics and other branches of the chemical industry as well as specialty polymers used in the electronics, pharmaceutical, medical, and space fields. Extensive information is [...] Read more.
Polymers selected for this edition of the Handbook of Polymers include all major polymeric materials used by the plastics and other branches of the chemical industry as well as specialty polymers used in the electronics, pharmaceutical, medical, and space fields. Extensive information is included on biopolymers. Full article
2953 KiB  
Review
Hybrid Block Copolymers Constituted by Peptides and Synthetic Polymers: An Overview of Synthetic Approaches, Supramolecular Behavior and Potential Applications
by Mireia Morell and Jordi Puiggalí
Polymers 2013, 5(1), 188-224; https://doi.org/10.3390/polym5010188 - 11 Feb 2013
Cited by 39 | Viewed by 13298
Abstract
Hybrid block copolymers based on peptides and synthetic polymers, displaying different types of topologies, offer new possibilities to integrate the properties and functions of biomacromolecules and synthetic polymers in a single hybrid material. This review provides a current status report of the field [...] Read more.
Hybrid block copolymers based on peptides and synthetic polymers, displaying different types of topologies, offer new possibilities to integrate the properties and functions of biomacromolecules and synthetic polymers in a single hybrid material. This review provides a current status report of the field concerning peptide-synthetic polymer hybrids. The first section is focused on the different synthetic approaches that have been used within the last three years for the preparation of peptide-polymer hybrids having different topologies. In the last two sections, the attractive properties, displayed in solution or in the solid state, together with the potential applications of this type of macromolecules or supramolecular systems are highlighted. Full article
(This article belongs to the Special Issue Bioconjugates/Biohybrid Polymers)
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482 KiB  
Review
Polyphosphazenes: Multifunctional, Biodegradable Vehicles for Drug and Gene Delivery
by Ian Teasdale and Oliver Brüggemann
Polymers 2013, 5(1), 161-187; https://doi.org/10.3390/polym5010161 - 8 Feb 2013
Cited by 125 | Viewed by 14214
Abstract
Poly[(organo)phosphazenes] are a unique class of extremely versatile polymers with a range of applications including tissue engineering and drug delivery, as hydrogels, shape memory polymers and as stimuli responsive materials. This review aims to divulge the basic principles of designing polyphosphazenes for drug [...] Read more.
Poly[(organo)phosphazenes] are a unique class of extremely versatile polymers with a range of applications including tissue engineering and drug delivery, as hydrogels, shape memory polymers and as stimuli responsive materials. This review aims to divulge the basic principles of designing polyphosphazenes for drug and gene delivery and portray the huge potential of these extremely versatile materials for such applications. Polyphosphazenes offer a number of distinct advantages as carriers for bioconjugates; alongside their completely degradable backbone, to non-toxic degradation products, they possess an inherently and uniquely high functionality and, thanks to recent advances in their polymer chemistry, can be prepared with controlled molecular weights and narrow polydispersities, as well as self-assembled supra-molecular structures. Importantly, the rate of degradation/hydrolysis of the polymers can be carefully tuned to suit the desired application. In this review we detail the recent developments in the chemistry of polyphosphazenes, relevant to drug and gene delivery and describe recent investigations into their application in this field. Full article
(This article belongs to the Special Issue Bioconjugates/Biohybrid Polymers)
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1819 KiB  
Article
Multiscale Modeling of Chemical Vapor Deposition (CVD) Apparatus: Simulations and Approximations
by Juergen Geiser
Polymers 2013, 5(1), 142-160; https://doi.org/10.3390/polym5010142 - 5 Feb 2013
Cited by 11 | Viewed by 5907
Abstract
We are motivated to compute delicate chemical vapor deposition (CVD) processes. Such processes are used to deposit thin films of metallic or ceramic materials, such as SiC or a mixture of SiC and TiC. For practical simulations and for studying the characteristics in [...] Read more.
We are motivated to compute delicate chemical vapor deposition (CVD) processes. Such processes are used to deposit thin films of metallic or ceramic materials, such as SiC or a mixture of SiC and TiC. For practical simulations and for studying the characteristics in the deposition area, we have to deal with delicate multiscale models. We propose a multiscale model based on two different software packages. The large scales are simulated with computational fluid dynamics (CFD) software based on the transportreaction model (or macroscopic model), and the small scales are simulated with ordinary differential equations (ODE) software based on the reactive precursor gas model (or microscopic model). Our contribution is to upscale the correlation of the underlying microscale species to the macroscopic model and reformulate the fast reaction model. We obtain a computable model and apply a standard CFD software code without losing the information of the fast processes. For the multiscale model, we present numerical results of a real-life deposition process. Full article
(This article belongs to the Special Issue Multiscale Simulations in Soft Matter)
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1526 KiB  
Article
Biodegradable Poly(butylene succinate) Composites Reinforced by Cotton Fiber with Silane Coupling Agent
by Buenaventurada P. Calabia, Fumi Ninomiya, Hisaaki Yagi, Akihiro Oishi, Kazuhiro Taguchi, Masao Kunioka and Masahiro Funabashi
Polymers 2013, 5(1), 128-141; https://doi.org/10.3390/polym5010128 - 29 Jan 2013
Cited by 102 | Viewed by 13240
Abstract
In this study, the use of cotton fiber (CF) as a filler in poly(butylene succinate) (PBS) and the effect of silane treatment on the mechanical properties, thermal stability, and biodegradability of PBS/CF composites are investigated. The results showed that the tensile strength of [...] Read more.
In this study, the use of cotton fiber (CF) as a filler in poly(butylene succinate) (PBS) and the effect of silane treatment on the mechanical properties, thermal stability, and biodegradability of PBS/CF composites are investigated. The results showed that the tensile strength of PBS was improved (15%–78%) with the incorporation of CF (10–40 wt%) and was further increased (25%–118%) when CF was treated with a silane coupling agent. Scanning electron microscopy (SEM) observation of the fracture surfaces of PBS/CF composites showed that there was slight improvement in fiber-matrix compatibility. Thermogravimetric (TG) analysis showed that the thermal stability of the composites was lower than that of neat PBS and decreased with increasing filler loading. The biobased carbon content of the composites increased with increasing CF content. The incorporation of CF (with and without silane treatment) in PBS significantly increased the biodegradation rate of the composites. Full article
(This article belongs to the Special Issue Polymers from Biomass)
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564 KiB  
Article
Thermal Properties of Aliphatic Polypeptoids
by Corinna Fetsch and Robert Luxenhofer
Polymers 2013, 5(1), 112-127; https://doi.org/10.3390/polym5010112 - 29 Jan 2013
Cited by 59 | Viewed by 8718
Abstract
A series of polypeptoid homopolymers bearing short (C1–C5) side chains of degrees of polymerization of 10–100 are studied with respect to thermal stability, glass transition and melting points. Thermogravimetric analysis of polypeptoids suggests stability to >200 °C. The study [...] Read more.
A series of polypeptoid homopolymers bearing short (C1–C5) side chains of degrees of polymerization of 10–100 are studied with respect to thermal stability, glass transition and melting points. Thermogravimetric analysis of polypeptoids suggests stability to >200 °C. The study of the glass transition temperatures by differential scanning calorimetry revealed two dependencies. On the one hand an extension of the side chain by constant degree of polymerization decrease the glass transition temperatures (Tg) and on the other hand a raise of the degree of polymerization by constant side chain length leads to an increase of the Tg to a constant value. Melting points were observed for polypeptoids with a side chain comprising not less than three methyl carbon atoms. X-ray diffraction of polysarcosine and poly(N-ethylglycine) corroborates the observed lack of melting points and thus, their amorphous nature. Diffractograms of the other investigated polypeptoids imply that crystalline domains exist in the polymer powder. Full article
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1693 KiB  
Review
Design and Synthesis of Cross-Linked Copolymer Membranes Based on Poly(benzoxazine) and Polybenzimidazole and Their Application to an Electrolyte Membrane for a High-Temperature PEM Fuel Cell
by Seong-Woo Choi, Jung Ock Park, Chanho Pak, Kyoung Hwan Choi, Jong-Chan Lee and Hyuk Chang
Polymers 2013, 5(1), 77-111; https://doi.org/10.3390/polym5010077 - 23 Jan 2013
Cited by 42 | Viewed by 13101
Abstract
Elevated-temperature (100~200 °C) polymer electrolyte membrane (PEM) fuel cells have many features, such as their high efficiency and simple system design, that make them ideal for residential micro-combined heat and power systems and as a power source for fuel cell electric vehicles. A [...] Read more.
Elevated-temperature (100~200 °C) polymer electrolyte membrane (PEM) fuel cells have many features, such as their high efficiency and simple system design, that make them ideal for residential micro-combined heat and power systems and as a power source for fuel cell electric vehicles. A proton-conducting solid-electrolyte membrane having high conductivity and durability at elevated temperatures is essential, and phosphoric-acid-containing polymeric material synthesized from cross-linked polybenzoxazine has demonstrated feasible characteristics. This paper reviews the design rules, synthesis schemes, and characteristics of this unique polymeric material. Additionally, a membrane electrode assembly (MEA) utilizing this polymer membrane is evaluated in terms of its power density and lifecycle by an in situ accelerated lifetime test. This paper also covers an in-depth discussion ranging from the polymer material design to the cell performance in consideration of commercialization requirements. Full article
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1688 KiB  
Article
Modeling and Simulation for Fuel Cell Polymer Electrolyte Membrane
by Kei Morohoshi and Takahiro Hayashi
Polymers 2013, 5(1), 56-76; https://doi.org/10.3390/polym5010056 - 21 Jan 2013
Cited by 29 | Viewed by 9323
Abstract
We have established methods to evaluate key properties that are needed to commercialize polyelectrolyte membranes for fuel cell electric vehicles such as water diffusion, gas permeability, and mechanical strength. These methods are based on coarse-graining models. For calculating water diffusion and gas permeability [...] Read more.
We have established methods to evaluate key properties that are needed to commercialize polyelectrolyte membranes for fuel cell electric vehicles such as water diffusion, gas permeability, and mechanical strength. These methods are based on coarse-graining models. For calculating water diffusion and gas permeability through the membranes, the dissipative particle dynamics–Monte Carlo approach was applied, while mechanical strength of the hydrated membrane was simulated by coarse-grained molecular dynamics. As a result of our systematic search and analysis, we can now grasp the direction necessary to improve water diffusion, gas permeability, and mechanical strength. For water diffusion, a map that reveals the relationship between many kinds of molecular structures and diffusion constants was obtained, in which the direction to enhance the diffusivity by improving membrane structure can be clearly seen. In order to achieve high mechanical strength, the molecular structure should be such that the hydrated membrane contains narrow water channels, but these might decrease the proton conductivity. Therefore, an optimal design of the polymer structure is needed, and the developed models reviewed here make it possible to optimize these molecular structures. Full article
(This article belongs to the Special Issue Polymers for Fuel Cells & Solar Energy)
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1138 KiB  
Article
Fabrication of Pd Doped WO3 Nanofiber as Hydrogen Sensor
by Alireza Nikfarjam, Somayeh Fardindoost and Azam Iraji zad
Polymers 2013, 5(1), 45-55; https://doi.org/10.3390/polym5010045 - 10 Jan 2013
Cited by 49 | Viewed by 10445
Abstract
Pd doped WO3 fibers were synthesized by electro-spinning. The sol gel method was employed to prepare peroxopolytungstic acid (P-PTA). Palladium chloride and Polyvinyl pyrrolidone (PVP) was dissolved in the sol Pd:WO3 = 10% molar ratio. The prepared sol was loaded into [...] Read more.
Pd doped WO3 fibers were synthesized by electro-spinning. The sol gel method was employed to prepare peroxopolytungstic acid (P-PTA). Palladium chloride and Polyvinyl pyrrolidone (PVP) was dissolved in the sol Pd:WO3 = 10% molar ratio. The prepared sol was loaded into a syringe connected to a high voltage of 18.3 kV and electrospun fibers were collected on the alumina substrates. Scanning electron microscope (SEM), X-ray powder diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques were used to analyze the crystal structure and chemical composition of the fibers after heat treatment at 500 °C. Resistance-sensing measurements exhibited a sensitivity of about 30 at 500 ppm hydrogen in air, and the response and recovery times were about 20 and 30 s, respectively, at 300 °C. Hydrogen gas sensing mechanism of the sensor was also studied. Full article
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3318 KiB  
Review
Hierarchically Structured Electrospun Fibers
by Nicole E. Zander
Polymers 2013, 5(1), 19-44; https://doi.org/10.3390/polym5010019 - 7 Jan 2013
Cited by 113 | Viewed by 18791
Abstract
Traditional electrospun nanofibers have a myriad of applications ranging from scaffolds for tissue engineering to components of biosensors and energy harvesting devices. The generally smooth one-dimensional structure of the fibers has stood as a limitation to several interesting novel applications. Control of fiber [...] Read more.
Traditional electrospun nanofibers have a myriad of applications ranging from scaffolds for tissue engineering to components of biosensors and energy harvesting devices. The generally smooth one-dimensional structure of the fibers has stood as a limitation to several interesting novel applications. Control of fiber diameter, porosity and collector geometry will be briefly discussed, as will more traditional methods for controlling fiber morphology and fiber mat architecture. The remainder of the review will focus on new techniques to prepare hierarchically structured fibers. Fibers with hierarchical primary structures—including helical, buckled, and beads-on-a-string fibers, as well as fibers with secondary structures, such as nanopores, nanopillars, nanorods, and internally structured fibers and their applications—will be discussed. These new materials with helical/buckled morphology are expected to possess unique optical and mechanical properties with possible applications for negative refractive index materials, highly stretchable/high-tensile-strength materials, and components in microelectromechanical devices. Core-shell type fibers enable a much wider variety of materials to be electrospun and are expected to be widely applied in the sensing, drug delivery/controlled release fields, and in the encapsulation of live cells for biological applications. Materials with a hierarchical secondary structure are expected to provide new superhydrophobic and self-cleaning materials. Full article
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277 KiB  
Review
Plastic Degradation and Its Environmental Implications with Special Reference to Poly(ethylene terephthalate)
by Hayden K. Webb, Jaimys Arnott, Russell J. Crawford and Elena P. Ivanova
Polymers 2013, 5(1), 1-18; https://doi.org/10.3390/polym5010001 - 28 Dec 2012
Cited by 671 | Viewed by 111991
Abstract
With increasing global consumption and their natural resistance to degradation, plastic materials and their accumulation in the environment is of increasing concern. This review aims to present a general overview of the current state of knowledge in areas that relate to biodegradation of [...] Read more.
With increasing global consumption and their natural resistance to degradation, plastic materials and their accumulation in the environment is of increasing concern. This review aims to present a general overview of the current state of knowledge in areas that relate to biodegradation of polymers, especially poly(ethylene terephthalate) (PET). This includes an outline of the problems associated with plastic pollution in the marine environment, a description of the properties, commercial manufacturing and degradability of PET, an overview of the potential for biodegradation of conventional polymers and biodegradable polymers already in production. Full article
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