Journal Sciences News
The Journal of Pain
February 2018
Comparison study of hydrolytic degradation behaviors between
February 2018
Synthesis and flame retardant efficacy of hexakis(3-(triethoxysilyl)propyloxy)cyclotriphosphazene/silica coatings for cotton fabrics
Publication date: February 2018
Source:Polymer Degradation and Stability, Volume 148 Author(s): Micha
February 2018
Application of ammonia pretreatment to enable enzymatic hydrolysis of hardwood biomass
Publication date: February 2018
Source:Polymer Degradation and Stability, Volume 148 Author(s): Kiyoshi Sakuragi, Kiyohiko Igarashi, Masahiro Samejima Ammonia pretreatment greatly improves enzymatic hydrolysis of grass biomass, but is reported to be ineffective for hardwood biomass. Here, we examined the effectiveness of ammonia pretreatment of biomass from six hardwood species with different contents of xylan and lignin. Ammonia pretreatment greatly improved enzymatic hydrolysis of polysaccharides in birch and willow, but was less effective for acacia, eucalyptus, and poplar. The effectiveness of ammonia pretreatment increased with xylan content but decreased with lignin content of the hardwood species. By adding a recombinant xylanase to the commercial enzyme digestion cocktail, the yield of enzymatic hydrolysis of ammonia-pretreated birch biomass was improved to a similar level to that obtained with grass biomass. Our results indicate that enzymatic hydrolysis of biomass from hardwood species having a relatively high xylan/lignin ratio can be achieved with a xylanase-enriched enzyme cocktail after ammonia pretreatment.
February 2018
Highly efficient flame-retardant glass-fiber-reinforced polyamide 6T system based on a novel DOPO-based derivative: Flame retardancy, thermal decomposition, and pyrolysis behavior
Publication date: February 2018
Source:Polymer Degradation and Stability, Volume 148 Author(s): Weijiang Huang, Wentao He, Lijuan Long, Wei Yan, Min He, Shuhao Qin, Jie Yu A novel bridged 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) derivative (PN-DOPO) was used to fabricate a flame-retardant glass fiber-reinforced polyamide 6T (GFPA6T). The effects of PN-DOPO on the flame retardancy, thermal decomposition, and pyrolysis behavior of GFPA6T was systematically investigated, compared to neat GFPA6T and its composite flames retarded by aluminium diethylphosphinate (OP1230). The flame retardancy, thermal stabilities, and burning behaviors of the composites were evaluated by vertical burning test (UL-94), limiting oxygen index (LOI), thermogravimetric analysis (TGA), and cone calorimeter test. Moreover, the flame-retardant mechanism was analyzed by pyrolysis-gas chromatograph/mass spectrometer (Py-GC/MS), Fourier transform infrared coupled with the thermogravimetric analyzer (TG-FTIR), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Results reveal that the modified GFPA6T, with the addition of 15
February 2018
The anaerobic biodegradation of poly(lactic) acid textiles in photosynthetic microbial fuel cells: Self-sustained bioelectricity generation
Publication date: February 2018
Source:Polymer Degradation and Stability, Volume 148 Author(s): Xiang Qi, Yi Bo, Yiwei Ren, Xingzu Wang Poly(lactic) acid (PLA) is a promising material due to the complete biodegradability and environmental-friendly characteristics, but it is difficult to decompose by traditional anaerobic composting. Photosynthetic microbial fuel cells (MFC) are envisaged as a potential bioenergy harvesting techniques in recent years. In this work, the anaerobic biodegradation of PLA textiles for bioelectricity generation was explored in a dual chamber MFC devices using the hybrid anoxygenic photosynthetic bacteria (APB). The result showed that the surface of PLA textiles appeared the widespread damage by SEM micrographs observation, and the corresponding weight loss was 26.67%. The analysis of FT-IR suggested that the breakage process was a biochemical action due to the function of depolymerase. Meanwhile, a stable current density generation of 4.4
Available online 17 January 2018
Effect of ZnO particle sizes on thermal aging behavior of natural rubber vulcanizates
Publication date: February 2018
Source:Polymer Degradation and Stability, Volume 148 Author(s): Yong Hwan Lee, Misuk Cho, Jae-Do Nam, Youngkwan Lee The effects of ZnO particle size on crosslinking and thermal aging behavior of natural rubber (NR) were investigated. NR vulcanizates filled with nano ZnO allowed higher crosslink density, lower polysulfide crosslink, and stronger mechanical properties than those filled with micro ZnO. After thermal aging, NR filled with nano ZnO exhibited much more stable chemical and mechanical properties. The high crosslink density as well as the formation of more stable mono- and di-sulfidic crosslinks was attributed to the good dispersion and high surface area of the nano ZnO.
Available online 17 January 2018
A propane burner test for passive fire protection (PFP) formulations containing added halloysite, carbon nanotubes and graphene
Publication date: Available online 17 January 2018
Source:Polymer Degradation and Stability Author(s): A.G. Gibson, W.N.B. Wan-Jusoh, G. Kotsikos Passive fire protection materials (PFP) have been characterised quantitatively using a constant heat flux propane burner test, with the PFP attached to a steel substrate. The burner test was able to produce a large, constant heat flux, to simulate a severe fire condition. The heat transferred through the PFP was calculated from the temperature rise of the steel. A simplified model is discussed, to account for different combinations of substrate thickness, PFP thickness, heat flux and exposure time. It was found that, despite the complex processes of resin decomposition and intumescence, heat transmission could be modelled, to a reasonable approximation, by treating the PFP as a material with single point values of apparent thermal diffusivity and conductivity. This leads to an equation that can be used to characterise PFPs and indeed to specify their required thickness. The burner test was employed to interpret the effects of adding small quantities of three nano-materials: halloysite nanotubes (HNT), multi-walled carbon nanotubes (MWCNT) and graphene nanoplatelets (GNP), to a standard PFP formulation. It was found that HNT addition resulted in a significant performance improvement, whereas the other nano-materials did not produce an improvement.
Available online 11 January 2018
Chemical recycling of poly(lactic acid) by water-ethanol solutions
Publication date: Available online 17 January 2018
Source:Polymer Degradation and Stability Author(s): Fabiola I
Available online 11 January 2018
Effect of carbon black distribution on the properties of polyethylene pipes part 1: Degradation of post yield mechanical properties and fracture surface analyses
Publication date: Available online 11 January 2018
Source:Polymer Degradation and Stability Author(s): Suleyman Deveci, Nisha Antony, Birkan Eryigit In this study, we investigated the effect of carbon black distribution on the degradation of mechanical properties of high-density polyethylene in the form of plastic pipes used in water distribution networks. Polyethylene pipes with similar carbon black concentrations but different carbon black distributions were produced with industrial scale compounding and extrusion equipment. Tensile specimens were directly prepared from extruded pipe samples and elongated to fracture at different strain rates. Carbon black distributions of bulk samples and fracture surfaces were investigated using stereo and scanning electron microscopy (SEM). It was found that the carbon black distributions, fracture surfaces and fracture modes were significantly different in these pipes. Although the yield properties were similar, the post-yield properties of samples were significantly different, dramatically decreasing with the increasing inhomogeneity of carbon black distribution. Pipes with a certain level of heterogeneity in the carbon black distribution showed ductile and brittle fractures in the same fracture plane, whereas homogenous black and natural polyethylene (without carbon black) showed ductile fractures only.
Available online 9 January 2018
Coupled aging effects in nanofiber-reinforced siloxane foams
Publication date: Available online 11 January 2018
Source:Polymer Degradation and Stability Author(s): Andrea Labouriau, Tom Robison, Drew Geller, Carl Cady, Adam Pacheco, Jamie Stull, Joseph H. Dumont This study investigates the combined effects of ionizing radiation and thermal treatments on the aging of siloxane foams containing small amounts of carbon nanofibers. Our siloxane foams were exposed to accelerated aging conditions for more than two years, resulting in very low dose rates. In addition, foams were aged under compressive load to evaluate the strength of the porous microstructure. Samples were characterized by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), M
Available online 9 January 2018
Corrigendum to ESR spin trapping determination of the hydroperoxide concentration in polyethykene oxide (PEO) in aqueous solution [Polym. Degrad. Stabil. vol. 139 (2017) 89-96]
Publication date: Available online 9 January 2018
Source:Polymer Degradation and Stability Author(s): Liang Chen, Shuzo Kutsuna, Shogo Yamane, Junji Mizukado
Available online 9 January 2018
Transparent and soluble polyimide films from 1,4:3,6-dianhydro-D-mannitol based dianhydride and diamines containing aromatic and semiaromatic units: Preparation, characterization, thermal and mechanical properties
Publication date: Available online 9 January 2018
Source:Polymer Degradation and Stability Author(s): Zhiming Mi, Zhixiao Liu, Jianan Yao, Chunbo Wang, Changjiang Zhou, Daming Wang, Xiaogang Zhao, Hongwei Zhou, Yumin Zhang, Chunhai Chen To develop colorless and soluble polyimide films, a novel dianhydride containing 1,4:3,6-dianhydro-D-mannitol unit, 2,5-bis(3,4-dicarboxyphenoxy)-1,4:3,6-dianhydromannitol dianhydride (IMDA) was synthesized. And two series of polyimides were prepared via a two-step thermal imidization, PI
Available online 8 January 2018
Crystallization kinetics of polylactide: Reactive plasticization and reprocessing effects
Publication date: Available online 9 January 2018
Source:Polymer Degradation and Stability Author(s): Berit Br
Available online 5 January 2018
Key role of magnesium hydroxide surface treatment in the flame retardancy of glass fiber reinforced polyamide 6
Publication date: Available online 8 January 2018
Source:Polymer Degradation and Stability Author(s): M. Casetta, G. Michaux, B. Ohl, S. Duquesne, S. Bourbigot In this paper, the fire retardant properties of two magnesium dihydroxide (MDH) were compared into glass fiber reinforced polyamide 6 (PA6 GF). The difference between the additives lies in the presence of a vinylsilane treatment at the surface of one of the two MDH (H5A grade) whereas the other is a non-treated MDH (H5 grade). The investigations showed that better fire properties were obtained with PA6 GF/H5A formulation compared to the PA6 GF/H5 one. More precisely, a higher UL-94 rating, a higher glow wire ignition temperature (GWIT) and a higher time to ignition (TTi) at the mass loss calorimeter (MLC) were obtained. To understand the differences between H5 and H5A in terms of fire performances, the mechanisms of degradation of the two fire retarded (FR) formulations was investigated, analyzing both the gas phase and the condensed phase. A significant part of the study was also devoted to the characterization of the ceramic protective layer formed thanks to the use of MDH. The analysis of the gas phase revealed that the degradation products of the two FR formulations were similar. Moreover, as shown by the condensed phase analysis, no chemical reaction occurs between PA6 and H5 or H5A, proving that the MDH surface treatment was not involved in chemical reactions during the processing of the formulation or its degradation. On the contrary, the main differences between the two formulations concern the properties of protective layer formed during the degradation. It was shown that the silane treatment and the MgO formed during MDH dehydration lead to the formation of a cohesive structure between the glass fibers when the material degrades, resulting in a highly insulating and resistant protective layer.
Available online 4 January 2018
Control of the secondary crystallisation process in poly(hydroxybutyrate-co-hydroxyvalerate) through the incorporation of poly(ethylene glycol)
Publication date: Available online 5 January 2018
Source:Polymer Degradation and Stability Author(s): Catherine A. Kelly, Annabel V.L. Fitzgerald, Mike J. Jenkins Poly(hydroxybutyrate-co-hydroxyvalerate) (PHB-co-HV) is a sustainable and biodegradable polymer, but as a potential packaging material, it suffers from a narrow processing window and embrittlement over time due to secondary crystallisation. This study aims to extend previous research by exploring the effect of the addition of poly(ethylene glycol) (PEG), in a range of molecular weights and compositions, on the rate of embrittlement. On blending, it was apparent that there was a reduction in both the melting point (of up to 7
Available online 4 January 2018
Exterior and under glass natural weathering of hemp fibers reinforced polypropylene biocomposites: Impact on mechanical, chemical, microstructural and visual aspect properties
Publication date: Available online 4 January 2018
Source:Polymer Degradation and Stability Author(s): C
January 2018
Correlation between artificial and natural weathering of hemp fibers reinforced polypropylene biocomposites
Publication date: Available online 4 January 2018
Source:Polymer Degradation and Stability Author(s): C
January 2018
Editorial Board
Publication date: January 2018
Source:Polymer Degradation and Stability, Volume 147

January 2018
Effect of the individual and combined use of cardanol-based plasticizers and epoxidized soybean oil on the properties of PVC
Publication date: January 2018
Source:Polymer Degradation and Stability, Volume 147 Author(s): Sangjun Lee, Min Su Park, Jihoon Shin, Young-Wun Kim The cardanol-derived plasticizers cardanol acetate (CA) and epoxidized cardanol acetate (ECA) were prepared from a renewable resource, cashew nut shell liquid (CNSL), and their plasticization efficiencies were investigated. The thermal decomposition temperatures of the cardanol derivatives were higher than that of the common petroleum-based plasticizer di-2-ethylhexyl phthalate (DOP) in the order ECA>CA>DOP. The tensile strains of the PVCs containing CA and ECA were ca. 705810%, and the tensile strengths were ca. 17.419.1MPa, which were higher than those of PVC containing DOP. The results of a Fourier transform infrared spectroscopy (FT-IR/ATR) and dynamic mechanical analysis (DMA) showed that the compatibility of ECA with PVC was excellent, and the T g of PVC containing 50 phr of ECA decreased to 27.4C. In studies on the combination of a primary plasticizer with epoxidized soybean oil (ESBO), it has been shown that the addition of small amounts (5 phr) of ESBO to ECA improves not only the thermal stability but also the mechanical properties, despite the insufficient compatibility of ESBO and PVC. It can be inferred that the mixture of ECA and ESBO improves the affinity of ESBO and PVC, thereby reducing the polymer chain interactions. Finally, in the leaching tests, the weight loss of PVC containing 50 phr of ECA was reduced to 2%, confirming that ECA is highly resistant to migration to water. As a result, the combination of two biobased plasticizers, ECA and ESBO, could be a good candidate to replace DOP.

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January 2018
Inherently flame retardant vinyl bearing hyperbranched polysiloxanes having improved thermal stability-Ceramization and analysis of associated thermal properties
Publication date: January 2018
Source:Polymer Degradation and Stability, Volume 147 Author(s): K. Indulekha, Deepthi Thomas, N. Supriya, R.S. Rajeev, Dona Mathew, K.N. Ninan, C. Gouri This study describes the synthesis and characterization of novel hyperbranched silicone polymers having high thermal stability and inherent flame retardancy achieved purely by molecular architecture, without the incorporation of any specific additive or filler. A series of hyper-branched terpolymers (MeDPhDViT) containing vinyl, phenyl and methyl moieties were synthesized by the acid catalysed copolymerization of vinyltriethoxysilane (VTES), diphenyldimethoxysilane (DPDMS) and dimethyldiethoxysilane (DMDES). Curing of these polymers is effected through condensation of the hydroxyl groups triggered by dibutyltindiluarate (DBTDL) catalyst. Glass to rubber transition temperature (Tg)of the cured polymers vary systematically from
January 2018
Grafting of phosphorus flame retardants on flax fabrics: Comparison between two routes
Publication date: January 2018
Source:Polymer Degradation and Stability, Volume 147 Author(s): Raymond Hajj, Roland El Hage, Rodolphe Sonnier, Belkacem Otazaghine, Benjamin Gallard, Sophie Rouif, Michel Nakhl, Jos
January 2018
Design of low molecular weight pectin and its nanoparticles through combination treatment of pectin by microwave and inorganic salts
Publication date: January 2018
Source:Polymer Degradation and Stability, Volume 147 Author(s): Badrul Hisyam Zainudin, Tin Wui Wong, Halimaton Hamdan This study examined primarily the molecular weight and degree of esterification profiles of pectin in response to treatment by microwave as a function of irradiation duration in combination with monovalent (sodium chloride) or divalent (calcium acetate) inorganic salt. The possibility of formation and physical attributes of nanoparticles prepared form these pectins were assessed against their suitability for use as nanocarrier in cancer therapy. The pectin was treated by microwave (900W) with inorganic salts as the promoter of superheating at liquid state. Its molecular weight, degree of esterification, viscosity, particle size, zeta potential and elemental content were determined. The pectin was subjected to nanospray drying with the size, zeta potential and morphology of the formed nanoparticles examined. The use of calcium acetate translated to the formation of pectin with lower molecular weight and degree of esterification, but higher solution viscosity than that of sodium chloride. Fourier transform infrared spectroscopy, particle size and elemental content analysis indicated such pectin had its molecules crosslinked by soluble calcium at COO
January 2018
PLA-PBAT-PLA tri-block copolymers: Effective compatibilizers for promotion of the mechanical and rheological properties of PLA/PBAT blends
Publication date: January 2018
Source:Polymer Degradation and Stability, Volume 147 Author(s): Yue Ding, Bo Lu, Pingli Wang, Gexia Wang, Junhui Ji Polylactide-poly(butylene adipate-co-terephthalate)-polylactide tri-block copolymers incorporating PLA blocks (LPB and HPB) with different chain lengths were synthesized as compatibilizers for PLA/PBAT blends. The structure of the tri-block copolymers could be adjusted by varying the feeding ratios of the monomer and macro-initiator, and the polymers were characterized by 1H NMR, 13C NMR, GPC, and DSC measurements. Compared to the short chains of the PLA blocks (LPB) in the copolymers, HPB was a more effective compatibilizer for two immiscible blends because the long chains achieve enhanced interpenetration of the relevant homopolymers. The elongation between the blocks of the PLA/PBAT blends with 5% HPB compatibilizer was seven times more than that of the pristine blends. The addition of compatibilizer reduced the particle size of the dispersed phase from 1.5
January 2018
Effects of environmental aging on physical properties of aromatic thermosetting copolyester matrix neat and nanocomposite foams
Publication date: January 2018
Source:Polymer Degradation and Stability, Volume 147 Author(s): Mete Bakir, Christine N. Henderson, Jacob L. Meyer, Junho Oh, Nenad Miljkovic, Maciej Kumosa, James Economy, Iwona Jasiuk This paper focuses on the effects of cyclic water immersion and salt spray aging tests on the physical properties of aromatic thermosetting copolyester (ATSP) matrix. Neat and graphene nanoplatelet (GNP) incorporated nanocomposite ATSP foam morphologies are employed to have enhanced surface areas exposed to the surrounding aqueous media, via porous configurations, which deliberately aggravate the extent of the aging on the matrix. The ATSP foams are fabricated through a thermal condensation polymerization process. Upon exposures to the periodic aging conditions, ATSP demonstrates an adsorption-regulated mass uptake mechanism. Contact angle measurements reveal GNP-neutral and hydrophobic characteristics for the ATSP matrix. Microstructural imaging exhibits no substantial physical degeneration in the matrix caused by the accelerated aging conditions. Glass transition temperatures of both neat and nanofiller incorporated ATSP forms display only marginal decreases stemmed from small volumes in the matrix occupied through the hygroscopic swelling. Thermal degradation stability of the ATSP morphology is effectively preserved following the aging processes. Compressive mechanical strengths of the foams lie within the regime of their virgin (not exposed to the aging conditions) counterparts yet show slight reductions. The ATSP matrix demonstrates an outstanding aging resistance to the subjected environments which can potentially address high-performance requirements in cutting-edge industrial applications.
January 2018
Tuning the structure and performance of silk biomaterials by combining mulberry and non-mulberry silk fibroin
Publication date: January 2018
Source:Polymer Degradation and Stability, Volume 147 Author(s): Xiufang Li, Jie Zhang, Yanfei Feng, Shuqin Yan, Qiang Zhang, Renchuan You Despite considerable efforts toward the biomedical applications of silk fibroin (SF), detailed control of structure and performance in silk biomaterials remains a major challenge. Silks are classified as mulberry and non-mulberry, which are produced by domesticated Bombyx mori and wild silkworm species, respectively. To achieve silk biomaterials with tunable performance, Bombyx mori silk fibroin (BSF) and non-mulberry Antheraea pernyi silk fibroin (ASF) were blended. These systems exploit the beneficial material and biological properties of both silk proteins. The sol-gel transition of ASF was much more rapid than that of BSF. Consequently, the gelation rate of SF solution could be controlled ranging from tens of minutes to days by changing the ASF ratio, providing useful options for the fabrication of silk hydrogels. Raising BSF ratio in the blend materials significantly increased mechanical performance, overcoming the inherent lack of mechanical performances of regenerated ASF materials. Conversely, increasing ASF ratio significantly enhanced degradability of the blend films, providing a wider range of regulation for the degradation rate of silk biomaterials. As a result, this simple blending strategy enables the process to be more controllable and flexible, controlling the performance of silk protein becomes feasible, and this would greatly expand the applications of silk as a biomedical material.
January 2018
Thermal degradation of SBS in bitumen during storage: Influence of temperature, SBS concentration, polymer type and base bitumen
Publication date: January 2018
Source:Polymer Degradation and Stability, Volume 147 Author(s): Sumit K. Singh, Yogesh Kumar, Sham S. Ravindranath One of the major issues that manufacturers and suppliers of styrene-butadiene-styrene (SBS) modified bitumen face is erosion in its properties during storage and transportation. If appropriate controls are not in place, properties of SBS modified bitumen can erode significantly during storage and transportation, resulting in substandard quality of roads when constructed using such products. We report a comprehensive study of the effect of storage temperature, SBS concentration, polymer type and base bitumen on the properties of polymer modified bitumen during storage at elevated temperatures in sealed aluminium tubes. Our results show that storage temperature, SBS concentration and polymer type play a major role in the observed property erosion, while type of base bitumen has a lesser effect. The samples were stored in sealed aluminium tubes at temperatures of 150C, 180C and 210C for up to 21 days. At 150C, the properties of PMB's remained intact even after storing for 21 days. But, significant erosion in conventional and rheological properties of SBS modified bitumen takes place within the first 3 days of storage at temperatures
January 2018
Degradation of some EN13432 compliant plastics in simulated mesophilic anaerobic digestion of food waste
Publication date: January 2018
Source:Polymer Degradation and Stability, Volume 147 Author(s): Wei Zhang, Sonia Heaven, Charles J. Banks The research looked at the anaerobic biodegradation of 9 different bioplastics, all of which were commercially available and certified in Europe as compostable packaging material compliant with the biodegradation and other requirements of the EN13432 standard. A combination of testing strategies was used to assess the degree of degradation both under batch conditions, and in a simulation in which the plastics and food waste were fed daily to a digester for a period of 147 days. Two non-biodegradable plastics were used as controls, and verified the robustness of the sampling regime and the recovery of the plastic film, with errors of <1% in the final balance. The simulation allowed quantification of the weight loss of the plastics and determination of a decay coefficient for the different materials, which was then used to estimate long-term degradation. Use of a biochemical methane potential (BMP) batch test allowed estimation of the conversion of carbon into gaseous products. There was no evidence that any of the plastic films inhibited the anaerobic digestion process when continuously fed to digesters, although some inhibition occurred when the most readily degradable materials were tested at higher concentrations in batch mode. There were some interesting differences between results from the various measures of plastic degradation in the batch and simulation experiments, with batch testing in most cases suggesting a higher degree of degradation than was achieved in a semi-continuous system at a solids retention time of 50 days. The exceptions to this were two plastics that appeared to show rapid weight loss in the simulation experiment. BMP test results confirmed this was not through biological conversion of the bioplastic to gaseous carbon products, and was therefore probably due to physical disintegration. It was concluded that, of the 9 bioplastics tested, only 4 showed substantial biodegradability under anaerobic conditions. Further evidence to support the mechanism of biodegradation was obtained by microscopy, and photomicrographs using different techniques are included to illustrate the process. Even the most degradable materials would not break down sufficiently to meet the physical contaminant criteria of the UK PAS110 specification for anaerobically digested material, if fed to a digester at 2.0% of the input load on a volatile solids basis.
January 2018
Effect of acrylonitrile sequence distribution on the thermal stabilization reactions and carbon yields of poly(acrylonitrile-co-methyl acrylate)
Publication date: January 2018
Source:Polymer Degradation and Stability, Volume 147 Author(s): Jian Hao, Yaodong Liu, Chunxiang Lu Polyacrylonitrile (PAN) copolymers are important precursors for making high performance carbon fibers. In this study, a type of inert comonomer, methyl acrylate (MA), was copolymerized with AN, and the effects of AN sequence distribution on the cyclization, oxidation and carbon yield were systematically studied. The sequence distribution of P(AN-co-MA) could be adjusted by altering MA/AN feeding ratio during radical polymerization. The number-average sequence length of AN in the copolymers decreases quickly along with the increase of MA content in PAN. The stabilization and carbonization weight losses were determined by thermogravimetric analysis, and the corresponding chemical changes were detected by Fourier transform infrared spectrums and X-ray photoelectron spectroscopy. The thermal cyclization and oxidation reactions were separated by altering gas environment from nitrogen to air, and were monitored by differential scanning calorimetry. It is concluded that the sequence distribution of AN in P(AN-co-MA) strongly affects reaction activation energies, cyclized structures and carbon yield.

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January 2018
Dose rate effects of gamma irradiation on silicone foam
Publication date: January 2018
Source:Polymer Degradation and Stability, Volume 147 Author(s): Bo Liu, Wei Huang, Yin-Yong Ao, Pu-Cheng Wang, You An, Hong-Bing Chen The dose rate effects of gamma irradiation on silicone foam were confirmed by investigating the relationships between the dose rate and the structures-property of the materials. With accumulation of the dose, the elongation at break (E b) decreases significantly, while the creep ratio slightly decreases and gas yield increases after irradiation in air, especially at lower dose rate. However, the main gas yields, including H2 and CH4, from samples irradiated in nitrogen do not increase linearly with reducing the dose rate. Furthermore, ESR spectra show that more radicals are generated at lower dose rate, indicating obvious dose rate effect. It is deduced that the dose rate effect is caused by the competition among the radical generation, reaction, and quenching rates.
January 2018
Seawater ageing of glass fiber reinforced epoxy nanocomposites based on silylated clays
Publication date: January 2018
Source:Polymer Degradation and Stability, Volume 147 Author(s): Bikramjit Sharma, Rahul Chhibber, Rajeev Mehta The performance of the fiber reinforced epoxy nanocomposites incorporating silylated clay minerals exposed to seawater ageing vis-
January 2018
Recognition of laser-marked quick response codes on polypropylene surfaces
Publication date: January 2018
Source:Polymer Degradation and Stability, Volume 147 Author(s): Chunlin Liu, Ying Lu, Yinglin Xiong, Qianpeng Zhang, Ankang Shi, Dun Wu, Hongwei Liang, Yuyuan Chen, Gang Liu, Zheng Cao Polystyrene-grafted antimony trioxide (Sb2O3-g-PS) was prepared as a laser-marking additive by free radical polymerization. Fourier transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy were used to characterize the modified Sb2O3 particles with a core-shell structure. Composites of polypropylene (PP) and modified or unmodified Sb2O3 were laser-marked using a neodymium-doped yttrium aluminum garnet laser at 1064nm. Compared with PP and unmodified Sb2O3 composites, the laser marking performance was dramatically improved for PP composites, with an equivalent amount of Sb2O3-g-PS. The marking patterns of quick response (QR) codes on the surface of PP composites containing Sb2O3-g-PS were clear and had a high contrast. The QR codes were easily and quickly recognized when the content of Sb2O3-g-PS reached 2.0wt%. The laser-induced blackening on the surface of the PP/Sb2O3-g-PS composite was due to the synergistic effect of Sb2O3 photothermal conversion and PS carbonization, which can effectively improve the laser marking performance and QR code recognition. We believe that the application of this core-shell laser additive will become prominent in the field of QR code marking, for polyolefins that are poor absorbers of the 1064nm wavelength.

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January 2018
Poly (MAH-
January 2018
Early stages of p-phenylenediamine antiozonants reaction with ozone: Radical cation and nitroxyl radical formation
Publication date: January 2018
Source:Polymer Degradation and Stability, Volume 147 Author(s): Franco Cataldo Physical-chemical considerations suggest that the diene rubber olefinic double bonds protection by N,N
January 2018
Intercalation of phosphotungstic acid into layered double hydroxides by reconstruction method and its application in intumescent flame retardant poly (lactic acid) composites
Publication date: January 2018
Source:Polymer Degradation and Stability, Volume 147 Author(s): Sheng Zhang, Yongxin Yan, Wenjia Wang, Xiaoyu Gu, Hongfei Li, Jianhua Li, Jun Sun Phosphotungstic acid is a typical kind of superior catalysts, and it is hardly to intercalate into the layered double hydroxides (LDH) by ion-exchange process because of its low negative charge. In this work, a phosphotungstic acid intercalated MgAl-LDH (PWA-LDH) was prepared by reconstruction method, and it was then introduced into poly (lactic acid) (PLA) resin in association with intumescent flame retardant (IFR) by melt blending to prepare a flame-retardant biodegradable PLA composite. The effects of PWA-LDH on the flame retardancy of PLA composites were characterized by limiting oxygen index (LOI), vertical burning test (UL-94) and cone calorimeter test. The results showed that the composite sample containing 18.0wt% IFR and 2.0wt% PWA-LDH achieved the maximal LOI value of 48.3%, passed the UL-94 V-0 rating, and significantly decreased the peak heat release rate from 306.3kW/m2 of neat PLA to 40.1kW/m2. Thermogravimetric analysis showed that both the thermal stability and the char formation were enhanced. The char morphology observation revealed that PWA-LDH was beneficial to form dense and compact char layers. It was demonstrated that there existed a synergistic effect between IFR and PWA-LDH in promoting the char formation and enhancing the fire resistance.
January 2018
Thermal and mechanical properties of graphene oxide nanocomposite hydrogel based on poly (acrylic acid) grafted onto amylose
Publication date: January 2018
Source:Polymer Degradation and Stability, Volume 147 Author(s): Reza Abdollahi, Mohammad Taghi Taghizadeh, Samira Savani In the present study, a nanocomposite hydrogel was synthesized based on poly (acrylic acid) grafted onto amylose (PAA-g-amylose) which was containing different loadings of graphene oxide (GO) nanosheets. The structural properties of optimized sample were characterized by X-ray analysis (XRD) and Fourier transform infrared spectroscopy (FTIR). The thermal and mechanical behaviors of synthesized hydrogel were investigated by thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC) and tensile testing. XRD and scanning electron microscopy study demonstrates the formation of highly exfoliated GO layers and its homogenous dispersion throughout the polymer matrix with 3 and 5wt% GO. However, the intercalated structure is predominant with 5wt% GO. The homogenous and the strong interaction of the GO layers and the PAA-g-amylose hydrogel matrix induced the significant improvement in thermal and mechanical properties of the nanocomposite hydrogel. The tensile strength and elastic modulus of the nanocomposite hydrogel increased by 124% and 26%, respectively with 3wt% GO loading. The thermal stability improved by 67C and Tg shifted higher temperature by 53C at 5wt% GO loading, compared to the pristine hydrogel matrix.
January 2018
Fire retardant sol-gel coated polyurethane foam: Mechanism of action
Publication date: January 2018
Source:Polymer Degradation and Stability, Volume 147 Author(s): S. Bellayer, M. Jimenez, B. Prieur, B. Dewailly, A. Ramgobin, J. Sarazin, B. Revel, G. Tricot, S. Bourbigot This paper investigates the flame retardant (FR) mechanism of action of a flexible PU foam, flame retarded with a sol-gel coating made of a mixture of tetraethoxysilane (TEOS), methyl triethoxysilane (MTES), 3-amino propyl triethoxysilane (APTES) and diethyl phosphite (DEP) in an ethanol/water solution. To build a mechanism of action, the coating as well as the residues obtained after fire testing were analyzed using solid state nuclear magnetic resonance (NMR), rheology, thermogravimetric analyses coupled with infrared detection (TGA-FTIR), microcalorimetry of combustion (MCC), smoke box and Pyrolysis Gas chromatography coupled with mass spectrometry (Py-GCMS). The coating shows an intumescent behavior upon burning exhibiting significant expansion and bubbling. The expansion occurs in two steps: a first step around 190C, related to the release of ethanol, and a second one around 380C, related to the release of non-degraded DEP, ammonia and propylene during degradation of the PU matrix. The flame retardant effect occurs (i) in the condensed phase by intumescence, which yields a thermal insulating layer made of a SiO2 and Si-O-P network mixed with orthophosphate at the surface of the PU foam, but also (ii) in the gas phase by the release of non-degraded DEP, which acts as free radical scavenger. The coating allows the protection of the underlying PU foam during burning as well as the reduction of the amount of smoke released.
January 2018
Effect of styrene butadiene rubber on the light pyrolysis of the natural rubber
Publication date: January 2018
Source:Polymer Degradation and Stability, Volume 147 Author(s): Pan Song, Xiaoyu Wu, Shifeng Wang The use of styrene butadiene rubber (SBR) in tire rubber presents a challenge for the recycling of tire rubber because of its complex degradation behavior compared with that of natural rubber (NR). The effect of the composition of SBR on the degradation of NR was observed by light pyrolysis at variable times at 300C. The morphology, sol-gel evolution of the NR/SBR blends and the degradation mechanism was investigated. In addition, the structural evolution of the sol and gel fractions were measured by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The results indicated that the mechanism of degradation between SBR and NR differed significantly at 300C. The broken molecular chains present in SBR recombined with themselves or those of NR to form a new crosslinked network. The results also showed that the ratio of NR/SBR in the sol and gel fractions remains almost constant and unrelated to the original ratio of the NR/SBR blends. Following an increase in SBR content, the sol fraction of different NR/SBR blends mainly consisted of the small molecular chains of NR, whereas the gel fraction mostly constituted re-crosslinked SBR molecular chains.
January 2018
Multi-scale and multi-technical analysis of the thermal degradation of poly(ether imide)
Publication date: January 2018
Source:Polymer Degradation and Stability, Volume 147 Author(s): Emilie Courvoisier, Yoann Bicaba, Xavier Colin The thermal degradation of PEI has been studied in wide ranges of temperature (between 180 and 250C) and oxygen partial pressure (between 0.21 and 50bars). On one hand, the chemical ageing mechanisms have been analysed and elucidated by FTIR spectrophotometry and by differential calorimetry (DSC) on sufficiently thin PEI films (between 10 and 60
January 2018
Influence of oxidation on the dynamics in amorphous ethylene-propylene-diene-monomer copolymer: A molecular dynamics simulation
Publication date: January 2018
Source:Polymer Degradation and Stability, Volume 147 Author(s): Weiwang Wang, Yasuhiro Tanaka, Tatsuo Takada, Shinya Iwata, Hiroaki Uehara, Shengtao Li This work is dedicated to the mechanism underlying the influence of the oxidation on the dynamic and static characteristics of ethylene-propylene-diene monomer (EPDM) copolymer. A molecular dynamics simulation was employed to provide an insight into the effects of oxidation on the micro and macroscopic properties, such as the density and self-diffusion, free volume, glass transition, and chain transition dynamics. The carbonyl product, the chain scission, and the crosslinking in the EPDM were considered. Self-coefficients and radial distribution function were analyzed to achieve the diffusion and the structure of the systems using a 10 ns produce run at an equilibrium (298K). The temperature dependence of glass transition and the autocorrelation function for internal torsional rotation have been discussed for understanding the chain dynamics and flexibility after aging, such as the relaxation time and the activation energy. It turns out that the introduction of more carbonyl groups suppresses the internal rotation and the conformational transition of the chains, resulting in the decrease of diffusion and less flexibility due to the strong polar interaction. A system associated with short chains after chain scission possesses a low activation energy, indicating a more flexibility of the chains. Furthermore, the crosslinked structure contributes to the weak chain transition of EPDM (higher T g) and the high modulus (harden). The different molecular dynamics could be derived from the interaction energy and the structures, such as polar and nonbonded interaction. Some aspects of the details of chain rotation are discussed in this paper.
January 2018
The effect of de- and re-polymerization during heat-treatment on the mechanical behavior of Scots pine sapwood under quasi-static load
Publication date: January 2018
Source:Polymer Degradation and Stability, Volume 147 Author(s): Michael Altgen, Tuuli Uimonen, Lauri Rautkari Loss in strength and ductility is a major drawback for the heat-treatment of solid wood. Previous studies focused mainly on the de-polymerization of cell wall constituents as a cause and the importance of the preferential removal of hemicelluloses. This study tested the hypothesis that the mechanical behavior of wood is additionally affected by re-polymerization reactions within the cell wall matrix during heat-treatment. This was achieved by comparing changes in chemical composition, FT-IR spectra, and mechanical properties of Scots pine sapwood that was heat-treated in either dry state in superheated steam or in wet state using pressurized hot water. Although preferential de-polymerization of hemicelluloses was evident for both heat-treatment techniques, the analysis of the chemical composition and FT-IR spectroscopy indicated additional re-polymerization reactions within the cell wall matrix of dry heat-treated wood. The consequent formation of covalent bonds and cross-links increased the resistance against compression loads and hindered inelastic deformation during bending. This resulted in an additional reduction in bending strength and strain energy density of dry compared to wet heat-treated wood. Re-polymerization reactions during heat-treatments of wood in dry state were suggested as the main cause for the brittle failure under bending loads, while the effect of hemicellulose-removal on brittleness was much smaller than stated previously.
January 2018
Multi detection in Size-Exclusion Chromatography of electron beam irradiated Ethylene Norbornene Copolymers
Publication date: January 2018
Source:Polymer Degradation and Stability, Volume 147 Author(s): Hala Barakat, Wowro Sonia Rosine Lago, Caroline Aymes-Chodur, Ange Privat Ahoussou, Najet Yagoubi Ethylene Norbornene Copolymers (ENCs) belong to the Cyclic Olefin Copolymers (COC) family and are used in numerous industrial fields. The goal of this paper is to compare the behavior under electron beam radiation of three grades of ENCs. Several radiation doses have been tested: 25kGy to simulate sterilization dose and higher doses (75 and 150kGy) to emphasize the electron beam effect on polymer ageing. By using Triple Detection (Refractometer/Laser Scattering/Viscometer) Size-Exclusion Chromatography, we wanted to study more accurately the evolution of ENCs under radiation than the previous studies available. Thanks to Triple detection, molecular weights were calculated without being dependent of calibration standards, branching was evidenced as the major effect of electron beams on those materials over a dose of 25kGy, and long chain branching and branching chains frequencies were also calculated. This study focuses on the effect of additive concentration and norbornene (NB) content and a trend has merged: for a same NB content, the higher the phenolic antioxidant concentration, the less crosslinked was the copolymer with the dose. By increasing NB content, radiation effects were minimized.
January 2018
Methanolysis of microbial polyester poly(3-hydroxybutyrate) catalyzed by Br
January 2018
PEG-based nanocomposite hydrogel: Thermo-responsive sol-gel transition and degradation behavior controlled by the LA/GA ratio of PLGA-PEG-PLGA
Publication date: January 2018
Source:Polymer Degradation and Stability, Volume 147 Author(s): Midori Kitagawa, Tomoki Maeda, Atsushi Hotta The sol-gel transition behavior and the degradation behavior of the nanocomposites consisting of laponite clay nanoparticles and poly(d,l-lactide-co-glycolide)-b-poly(ethylene glycol)-b-poly(d,l-lactide-co-glycolide) (PLGA-PEG-PLGA) triblock copolymers (laponite/PLGA-PEG-PLGA nanocomposites) were studied changing the LA/GA ratios of the PLGA blocks in the PLGA-PEG-PLGA. The thermo-responsive sol-gel transition at the physiological temperature (2537C) was observed using the PLGA-PEG-PLGA with a high PEG/PLGA ratio of
January 2018
Long term stabilization of PE by the controlled release of a natural antioxidant from halloysite nanotubes
Publication date: January 2018
Source:Polymer Degradation and Stability, Volume 147 Author(s): J
January 2018
Biodegradation rate of biodegradable plastics at molecular level
Publication date: January 2018
Source:Polymer Degradation and Stability, Volume 147 Author(s): Selene Chinaglia, Maurizio Tosin, Francesco Degli-Innocenti Plastics are solid materials where biodegradation happens on the surface. Only the surface is affected by biodegradation while the inner part should not be readily available for biodegradation. Thus, at a laboratory level, the biodegradation rate is expected to be a function of the surface area of the tested sample. The higher the surface area, the higher the biodegradation rate, all other environmental conditions being equal. In order to further explore the role of particle size on biodegradability, plastic pellets of polybutylene sebacate were milled and sieved into different particle sizes, thus obtaining four samples, pellets included, with different specific surface areas (33, 89, 193, and 824
January 2018
Mechanical recycling: Compatibilization of mixed thermoplastic wastes
Publication date: January 2018
Source:Polymer Degradation and Stability, Volume 147 Author(s): Joachim Maris, Sylvie Bourdon, Jean-Michel Brossard, Laurent Cauret, Laurent Fontaine, V
January 2018
The degradability and thermal properties of chiral polyamide-imides synthesized from several l-amino acids: Side group effects
Publication date: January 2018
Source:Polymer Degradation and Stability, Volume 147 Author(s): Ping Li, Fuyan He, Zhizhou Yang, Wenke Yang, Jinshui Yao A series of chiral optically active monomers were prepared from l-amino acids with different structures. These monomers were polymerized to chiral polyamide-imides (PAIs) via an eco-friendly direct polycondensation process. The glass transition temperature (Tg) values were obtained by differential scanning calorimetry (DSC), and showed that the rigid and bulk effect of the substituents will co-affect the Tg values of the polymers. Their degradability were studied via soil degradation experiments, and the variations of water contact angles, molecular weights, structure and appearance during degradation were characterized by contact angle tester, gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM) respectively. The results revealed that the damages of polymer chains started with the amide bonds, and then proceed to the imide rings. With degradation, PAI films' hydrophilicity raised, and when introduced amino acids with longer carbon chain or bulky ring into the polymers' backbone, their degradability decreased.

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January 2018
Weathering resistance of PMMA/SiO2/ZrO2 hybrid coatings for sandstone conservation
Publication date: January 2018
Source:Polymer Degradation and Stability, Volume 147 Author(s): Laura Bergamonti, Federica Bondioli, Ilaria Alfieri, Silvia Alinovi, Andrea Lorenzi, Giovanni Predieri, Pier Paolo Lottici Accelerated weathering of polymethylmethacrylate (PMMA) and of hybrid PMMA/SiO2/ZrO2 films was monitored by spectroscopic, thermal and colorimetric measurements. The hybrid polymers were obtained by sol-gel process adding tetraethylorthosilicate (TEOS) and zirconyl chloride (ZrOCl2*8H2O) to a solution of PMMA. Photo ageing tests on polymeric films under artificial sunlight irradiation in a climatic chamber suggest that the addition of the inorganic fillers slows down the chemical degradation of PMMA. The polymers were deposited on two different sandstones from Tuscany (Italy): Pietra Dorata and Pietra Serena. Capillary water absorption, contact angle and color measurements show that the hybrid-PMMA coatings retain the water repellency of the sandstone and do not introduce noticeable changes of the aesthetic appearance. Accelerated weathering of the treated sandstone confirms that the SiO2/ZrO2 inorganic filler delays the chromatic changes of the polymer. The hybrid coating may then be proposed for application in the field of outdoor conservation of sandstones, used as building material in ancient and modern architectures.
Available online 14 December 2017
Identification of antioxidants in polymeric insulating materials by terahertz absorption spectroscopy
Publication date: January 2018
Source:Polymer Degradation and Stability, Volume 147 Author(s): Takuya Kozai, Takuya Kaneko, Naoshi Hirai, Yoshimichi Ohki For the purpose of using organic polymeric materials for electrical insulation, various additives such as antioxidants are added to prevent degradation or oxidative decomposition of the polymers. Therefore, it is desirable that we can identify antioxidants added in polymers by instrument analyses. In this research, terahertz absorption spectroscopy was conducted for nine kinds of antioxidants. The spectroscopy was also conducted for sheets of low-density polyethylene, to which each antioxidant had been added with different contents. As a result, it has become clear that each antioxidant has its own specific spectrum. In addition, for most antioxidants, the absorption intensity is proportional to the content of antioxidant added in LDPE. However, several absorption peaks change their spectral shapes when the antioxidant is in LDPE.

Plasma induced degradation and surface electronic structure modification of Poly(3-hexylthiophene) films
Publication date: Available online 14 December 2017
Source:Polymer Degradation and Stability Author(s): Marinos Tountas, Dimitra G. Georgiadou, Angelos Zeniou, Kostas Seintis, Anastasia Soultati, Ermioni Polydorou, Spyros Gardelis, Antonios M. Douvas, Thanassis Speliotis, Dimitris Tsikritzis, Stella Kennou, Mihalis Fakis, Evangelos Gogolides, Dimitris Tsoukalas, Panagiotis Argitis, Maria Vasilopoulou Plasma treatment is an environmentally friendly solution for modifying or nanostructuring the surface of several materials including photoactive polymers. The detailed characterization of the effect of plasma treatment on chemical and optoelectronic properties of photoactive polymers is, therefore, of specific interest. Herein, the effect of the exposure of poly(3-hexylthiophene) (P3HT) thin films to plasma created in three different gases (oxygen, argon and hydrogen) was studied. A range of spectroscopic techniques, such as x-ray (XPS) and ultraviolet (UPS) photoelectron spectroscopy in conjunction with UVvis absorption, Fourier transform infrared (FTIR) and photoluminescence (PL) spectroscopies, are employed to quantify the extent of chemical modification occurring in each particular case. It is shown that oxygen plasma treatment leads to the disruption of the
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