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August 2018
Highly effective flame retarded polystyrene by synergistic effects between expandable graphite and aluminum hypophosphite
Publication date: August 2018
Source:Polymer Degradation and Stability, Volume 154 Author(s): Zong-Min Zhu, Wen-Hui Rao, A-Hui Kang, Wang Liao, Yu-Zhong Wang Herein, expandable graphite (EG) and aluminum hypophosphite (AP) are used to prepare flame-retardant polystyrene (PS) composites. The flame-retardant properties of the PS composites are investigated by the limiting oxygen index (LOI) test, vertical burning test (UL-94) and cone calorimetry test (CC). With 15
August 2018
Development of a relationship between kinetic triplets and heating rates to improve pyrolysis kinetic modeling of polymer
Publication date: August 2018
Source:Polymer Degradation and Stability, Volume 154 Author(s): Xinyi Tang, Qiyuan Xie, Rong Qiu, Yun Yang Pyrolysis kinetic modeling of polymers is important for the analyses of their combustibility and flame spread mechanism in fire safety science and engineering. The objective of this work is to improve the reliable kinetic parameter analyses for polymers by introducing a new idea of the linear dependence of kinetic triplets on the heating rates in Thermogravimetric Analysis (TGA) experiments. The virtual kinetic triplets are also introduced for the case with the infinitely slow heating rate. Pyrolysis kinetic analyses are conducted by Genetic Algorithm (GA) optimization for the TGA data based on the single-scan, multi-scan and the new method here with the modified kinetic triplet series. The results show that the fitting errors for the independent case based on the single-scan method can be as small as 0.10.5%. But Kinetic Compensation Effects (KCE) problem is its main restriction to hinder the determination of reliable kinetic triplets. The results also show that based on the multi-scan method, the relatively reliable kinetic parameters can be calculated but with large total fitting errors in the range of 4.79.8%. Finally, the total fitting error can be minimized to about 0.61.7% by the new method here, which illustrates its obvious improvement for the reliable pyrolysis kinetic modeling of fuels. The new method based on the kinetic triplet series here is a modified multi-scan method, in which the traditional multi-scan method is also included as the case with the linear coefficient of zeros.
August 2018
Improving fire safety of epoxy filled with graphene hybrid incorporated with zeolitic imidazolate framework/layered double hydroxide
Publication date: August 2018
Source:Polymer Degradation and Stability, Volume 154 Author(s): Wenzong Xu, Xiaoling Wang, Yucheng Liu, Wu Li, Rui Chen In this work, a novel graphene (RGO) hybrid added with Zeolitic Imidazolate Framework/Layered Double Hydroxide (ZIF/LDH) was prepared to obtain a synergistic system (RGO-LDH/ZIF-67). Subsequently, RGO-LDH/ZIF-67 was mixed into epoxy resin (EP) by physical blending for the purpose of improving its fire safety. Based on a series of tests and analyses, it was found that RGO-LDH/ZIF-67 was beneficial to reducing the heat release of EP during its burning process. The peak heat release rate (PHRR) and total heat release (THR) of the composite with 2
August 2018
Simultaneous improvement of mechanical and fire retardant properties of synthesised biodegradable guar gum-g-poly(butyl acrylate)/montmorillonite nanocomposite
Publication date: August 2018
Source:Polymer Degradation and Stability, Volume 154 Author(s): Dharmendra K. Jena, Prafulla K. Sahoo A novel multicomponent biopolymer based nanocomposite was synthesised via graft copolymerization of butyl acrylate (BA) onto guar gum (GG) and montmorillonite (MMT) by using ammonium persulfate (APS) as a free radical initiator, in the presence of N,N
August 2018
Enhancing the biodegradation rate of poly(lactic acid) films and PLA bio-nanocomposites in simulated composting through bioaugmentation
Publication date: August 2018
Source:Polymer Degradation and Stability, Volume 154 Author(s): E. Castro-Aguirre, R. Auras, S. Selke, M. Rubino, T. Marsh Biodegradable polymers provide an opportunity to divert plastic waste from landfills, with composting as an alternative disposal route. However, some biodegradable polymers, such as poly (lactic acid) (PLA), do not biodegrade as fast as other organic wastes during composting, affecting their general acceptance in industrial composting facilities. Bioaugmentation, the addition of specific microbial strains, is a promising technique to accelerate the biodegradation of compostable plastics, so that they biodegrade in comparable time frames with other organic materials. In this study, we evaluated the effect of bioaugmentation on the biodegradation of PLA and PLA bio-nanocomposites (BNCs) in simulated composting conditions. PLA, PLA with 5% organo-modified montmorillonite (PLA-OMMT5), and PLA with 0.4% surfactant (PLA-QAC0.4) films were produced and fully characterized. PLA-degrading bacteria were isolated through an enrichment technique with PLA as the sole carbon source at 58
August 2018
Low molecular weight hindered amine light stabilizers (HALS) intercalated MgAl-Layered double hydroxides: Preparation and anti-aging performance in polypropylene nanocomposites
Publication date: August 2018
Source:Polymer Degradation and Stability, Volume 154 Author(s): Qian Zhang, Fabrice Leroux, Pinggui Tang, Dianqing Li, Yongjun Feng A low molecular weight hindered amine light stabilizer (HALS), contains 2, 2, 6, 6-tetramethyl piperidine functional group has been successfully prepared and intercalated into the interlayer region of Mg-Al layered double hydroxides (LDH) via a co-precipitation method to produce HALS-LDH. Furthermore, a series of HALS-LDH/PP nanocomposites were fabricated by dispersing HALS-LDH in poly(propylene) (PP) in a solvent casting route. Through the accelerated aging test method, the morphological properties, the thermal-oxidative degradation and photo-oxidative degradation behavior of HALS-LDH/PP composites were carefully investigated. The results show that the thermal stability of HALS in HALS-LDH was improved compared to that of HALS free of LDH dispersed into PP, and there is no negative effect on the crystallization behavior of PP after the addition of HALS-LDH. Besides, the HALS-LDH significantly enhances synergistically the thermal- and photo-stability of PP compared when LDH platelets CO3-LDH or HALS are used separately. Under the experimental conditions, a mass loading of HALS-LDH optimized as 4
August 2018
High performance nano-zinc amino-tris-(methylenephosphonate) in rigid polyurethane foam with improved mechanical strength, thermal stability and flame retardancy
Publication date: August 2018
Source:Polymer Degradation and Stability, Volume 154 Author(s): Lei Liu, Zhengzhou Wang A novel phosphorus and nitrogen-based flame retardant, zinc amino-tris-(methylenephosphonate) (Zn-AMP) was synthesized and characterized by X-ray diffraction and Fourier-transform infrared spectroscopies, transmission electronic microscopy, and thermogravimetric analysis (TGA). Zn-AMP was introduced into rigid polyurethane (RPU) foam with the aim of enhancing flame retardant, mechanical and thermal properties. The incorporation of 10
August 2018
Diffusion-limited oxidation of polyamide: Three stages of fracture behavior
Publication date: August 2018
Source:Polymer Degradation and Stability, Volume 154 Author(s): Xin-Feng Wei, Kai J. Kallio, Stefan Bruder, Martin Bellander, Hans-Henning Kausch, Ulf W. Gedde, Mikael S. Hedenqvist Polyamides (PAs) frequently experience diffusion-limited oxidation (DLO) under elevated temperatures due to their combination of relatively high oxygen barrier properties and high susceptibility to, and rate of, oxidation; under DLO conditions, oxidation is uneven and limited to a thin surface layer. In this study, the reduced extensibility/embrittlement of unstabilized PA6 under DLO conditions was understood by revealing DLO-induced fracture behavior. The DLO was induced by thermally ageing PA6 samples at 180
August 2018
A new insight into morphological, thermal, and mechanical properties of melt-processed polylactide/poly(
August 2018
Biobased copolyesters: Synthesis, structure, thermal and mechanical properties of poly(ethylene 2,5-furandicarboxylate-co-ethylene 1,4-cyclohexanedicarboxylate)
Publication date: August 2018
Source:Polymer Degradation and Stability, Volume 154 Author(s): Xiansong Wang, Qingyin Wang, Shaoying Liu, Gongying Wang A series of bio-based copolyesters, poly(ethylene 2,5-furandicarboxylate-co-ethylene 1,4-cyclohexanedicarboxylate)s (PEFCs) were synthesized from ethylene glycol (EG), 2,5-furandicarboxylic acid (FDCA) and 1,4-cyclohexanedicarboxylic acid (CHDA) through a two-step melt polycondensation procedure. The chemical structure, compositions and sequence distributions were determined by 1H NMR. The molecular weight, thermal properties, thermal stabilities, crystal structure and mechanical properties were investigated by GPC, DSC, TGA, WAXD, and tensile testing, respectively. All PEFCs showed the characteristic of random copolymer, and their composition could be controlled by the feed molar ratio of FDCA to CHDA. DSC results showed that PEFCs were amorphous, while increasing the content of the CHDA unit, the glass transition temperatures (Tg) of PEFCs decreased. Moreover, the thermal stabilities of all PEFCs remained unchanged. The tensile testing demonstrated that PEFC-30 was a toughened plastic with tensile modulus 801
August 2018
Oxidation reactions in kink banded regions of UHMMPE fiber-based laminates used in body armor: A mechanistic study
Publication date: August 2018
Source:Polymer Degradation and Stability, Volume 154 Author(s): Zois Tsinas, Amanda L. Forster, Mohamad Al-Sheikhly This work demonstrates the synergy between the thermo-mechanical and humidity induced degradation as well as the oxidation reactions in the kink-banded areas of ultra-high molar mass polyethylene (UHMMPE) fiber-based laminates used in body armor. For aged materials, the energy-dispersive X-ray spectroscopy (EDS) and Fourier transform infrared spectroscopy (FTIR) results reveal high concentrations of oxygen containing products, and the EPR results demonstrate the presence of the peroxyl radicals (RO2 ) in the kink-banded areas. After one year of dark ambient storage, very long-lived RO2 radicals were observed primarily in the samples exposed to ageing conditions of elevated temperatures, humidity, and mechanical stress. The total percentage of crystallinity, as measured by differential scanning calorimetry, of the kink-banded fibers was unchanged, indicating that the degradation occurs primarily in the amorphous region, and may also involve recrystallization processes of the degraded chains. However, the most abundant orthorhombic crystalline phase decreases from 77% to 70%. This decrease in the orthorhombic structure leads to more diffusion of oxygen into the kink-banded region, enhancing the oxidation processes. No changes are observed in the monoclinic phase of the kinked fibers, which remained constant and constituted
August 2018
Fire-resistant natural fibre-reinforced composites from flame retarded textiles
Publication date: August 2018
Source:Polymer Degradation and Stability, Volume 154 Author(s): W. Pornwannachai, J.R. Ebdon, B.K. Kandola Thermoplastic composites were prepared by melt pressing fabrics from commingled natural (flax) thermoplastic (polypropylene (PP) and polylactic acid (PLA)) polymeric fibres. Fabrics were treated with a number of commercial flame retardants (FRs) used for textiles prior to composite preparation. Their flammabilities and mechanical performances have been evaluated in terms of FR types effective on each fibre type. The fire performances of the composite laminates evaluated using UL-94 showed that flax/PP control and all flame retarded composite samples failed the UL-94 test, except for one treated with organophosphonate FR. On the other hand all flame retarded flax/PLA samples achieved V0 rating. Cone calorimetric results obtained at 35
August 2018
Biodegradable PHBH/PVA blend nanofibers: Fabrication, characterization, invitro degradation, and invitro biocompatibility
Publication date: August 2018
Source:Polymer Degradation and Stability, Volume 154 Author(s): Rina Afiani Rebia, S
August 2018
Anti-aging behavior of amino-containing co-condensed nanosilica in polyethylene
Publication date: August 2018
Source:Polymer Degradation and Stability, Volume 154 Author(s): Ming Lu, Peng Liu, Shimin Zhang, Wenjing Yuan, Siyin Ding, Feng Wang, Yanfen Ding, Mingshu Yang Physical loss of stabilizers by migration and extraction accelerates the degradation of polymer materials. In this work, amino-containing nanosilica with anti-aging properties was prepared simply by the co-condensation of tetraethoxysilane and N-(2-aminoethyl)-3-aminoproply-trimethoxysilane (AEAPS). AEAPS was used to introduce amino groups into silica nanoparticles and to act as a catalyst in this process. The co-condensed nanosilica (CCS) showed agglomerate structure similar to the typical fumed nanosilica (FS). The amino groups were distributed both on the surface and inside the nanoparticles. HDPE/CCS and HDPE/FS composites were prepared by melt blending. Thermogravimetric analysis and oxidative induction time showed that CCS has effectively improved the thermo-oxidative stability of HDPE. In the long-term accelerated thermo-oxidative aging and UV aging tests, HDPE/CCS composite showed superior stability to neat HDPE and HDPE/FS composite. The results of infrared spectroscopy and electron paramagnetic resonance suggested that the HDPE/CCS composite manifested a special degradation mechanism involving the nucleophilic addition of amino groups to carbonyl species as well as the oxidation of amino groups on CCS by peroxides. The amino groups on CCS consumed carbonyl species and peroxides, and generated hydroxylamines and nitroxide radicals which were able to eliminate free radicals, thus restrained the degradation of HDPE.
August 2018
Influences of diantimony trioxide on laser-marking properties of thermoplastic polyurethane
Publication date: August 2018
Source:Polymer Degradation and Stability, Volume 154 Author(s): Junfeng Cheng, Hao Li, Jiaqi Zhou, Zheng Cao, Dun Wu, Chunlin Liu The influences of diantimony trioxide (Sb2O3) on the laser-marking properties of thermoplastic polyurethane (TPU) are studied. The TPU/Sb2O3 composites are prepared by melt blending in a HAAKE mixer. A neodymium-doped yttrium aluminum garnet (Nd:YAG) pulsed laser beam of a wavelength of 1064
August 2018
Facile synthesis of a novel hyperbranched poly(urethane-phosphine oxide) as an effective modifier for epoxy resin
Publication date: August 2018
Source:Polymer Degradation and Stability, Volume 154 Author(s): Chao Ma, Shuilai Qiu, Junling Wang, Haibo Sheng, Yi Zhang, Weizhao Hu, Yuan Hu In this work, a novel hyperbranched poly (urethane-phosphine oxide) (HPUPO) was facilely synthesized from 4,4
August 2018
Enhanced crystallization kinetics of bacterially synthesized poly(3-hydroxybutyrate-co-3-hydroxyhexanate) with structural optimization of oxalamide compounds as nucleators
Publication date: August 2018
Source:Polymer Degradation and Stability, Volume 154 Author(s): Pengwu Xu, Ying Cao, Pei Lv, Piming Ma, Weifu Dong, Huiyu Bai, Wei Wang, Mingliang Du, Mingqing Chen Bacterially synthesized poly (3-hydroxybutyrate-co-3-hydroxyhexanate) (PHBH) has attracted much attention as biodegradable plastics and potential biomaterials. However, the crystallization rate of PHBH is very low, which limits its application in plastic field. Herein, oxalamide compounds (OXAn) with a formula of C6H5NHCOCONH(CH2)nNHCOCONHC6H5 (n
August 2018
A novel organic-inorganic hybrid SiO2@DPP for the fire retardance of polycarbonate
Publication date: August 2018
Source:Polymer Degradation and Stability, Volume 154 Author(s): Yun-Xia Wei, Cong Deng, Ze-Yong Zhao, Yu-Zhong Wang To enhance the fire retardance of polycarbonate (PC), a novel organic-inorganic hybrid particle containing phosphorus and silicon (SiO2@DPP) was synthesized through a facile hydrothermal reaction. Different measurements verified that the SiO2@DPP was prepared successfully. After incorporation of the SiO2@DPP into PC, it was found that the flame retardancy of PC was greatly affected by only small amount of SiO2@DPP. The PC containing only 0.8
August 2018
Water ageing of urethane dimethacrylate networks
Publication date: August 2018
Source:Polymer Degradation and Stability, Volume 154 Author(s): Benjamin Pomes, Isabelle Derue, Albert Lucas, Jean-Fran
August 2018
UV degradation model for polymers and polymer matrix composites
Publication date: August 2018
Source:Polymer Degradation and Stability, Volume 154 Author(s): T. Lu, E. Solis-Ramos, Y. Yi, M. Kumosa We are proposing in this work a new model of ultraviolet (UV) damage for polymers and Polymer Matrix Composites (PMCs). Flat and sinusoidal polymer surfaces were numerically simulated for their UV damage as a function of UV intensity, surface topography, and exposure time. Experimentally determined UV degradation rates for a unidirectional glass/epoxy composite were used to predict numerically the local rates of material degradation on sinusoidal epoxy surfaces subjected to UV. This allowed us to show that UV damage on uneven polymer surfaces reduces their surface roughness making them planar and that the degradation rates are the largest at the tips of the local heights of the surfaces. This was subsequently verified experimentally by exposing neat epoxy specimens to UV in air at 80
August 2018
Effect of mesoporous SBA-15 silica on the thermal stability of isotactic polypropylene based nanocomposites prepared by melt extrusion
Publication date: August 2018
Source:Polymer Degradation and Stability, Volume 154 Author(s): R. Barranco-Garc
July 2018
Situ preparation of SiO2 on graphene-assisted anti-oxidation for resol phenolic resin
Publication date: August 2018
Source:Polymer Degradation and Stability, Volume 154 Author(s): You Lv, Jian Li, Zixuan Lei, Ziqi Li, Xinli Jing, Yuhong Liu Easily oxidized group of traditional phenolic resin (PF) results in poor oxidation resistance at high temperature, which is unable to satisfy the requirements of advanced aerospace vehicles for high-performance application, especially ablation resistance. In order to improve the oxidation resistance of PF, a SiO2/RGO binary hybrid nanomaterial assisted anti-oxidation for PF was designed. Here, we reported a simple sol-gel process and high temperature reduction for synthesis of dispersed SiO2 nanoparticles on graphene (G-S). The designed structure of G-S was confirmed by FTIR, XRD, SEM and TEM. Introduction of G-S into PF (P-G-S) was beneficial to enhancement of oxidation resistance in whole temperature range (01000
July 2018
Editorial Board
Publication date: July 2018
Source:Polymer Degradation and Stability, Volume 153

July 2018
Impact of the formulation of biosourced phenolic foams on their fire properties
Publication date: July 2018
Source:Polymer Degradation and Stability, Volume 153 Author(s): C. Delgado-S
July 2018
Determination of the long-term performance of district heating pipes through accelerated ageing
Publication date: July 2018
Source:Polymer Degradation and Stability, Volume 153 Author(s): Alberto Vega, Nazdaneh Yarahmadi, Ignacy Jakubowicz The lifetime of pre-insulated district heating pipes (DHPs) is commonly evaluated using the method described in the normative European Standard EN 253. This lifetime is normally calculated using an Arrhenius equation, which makes use of test results from accelerated ageing tests at elevated temperatures. In this investigation, long-term accelerated ageing tests of DHPs at elevated temperatures were carried out. The ageing behaviour, especially at the interface between steel pipe and polyurethane (PUR) foam, showed several routes of degradation. It is clearly demonstrated using measurements of shear strength, thermal conductivity and alterations of chemical structure by Fourier Transform Infrared spectroscopy that the results of accelerated ageing at 170 and 150
July 2018
Comparative study of the photochemical stability of HDPE/Ag composites
Publication date: July 2018
Source:Polymer Degradation and Stability, Volume 153 Author(s): Ifigenia Grigoriadou, Eleni Pavlidou, Kostas M. Paraskevopoulos, Zoi Terzopoulou, Dimitrios N. Bikiaris In the present study, HDPE composites containing different concentrations of silver (Ag) nanoparticles (0.5%, 1%, 2%, 3%, and 5
July 2018
Stabilization of recombinant spider silk in thermo-oxidative degradation: High-throughput screening for antioxidants
Publication date: July 2018
Source:Polymer Degradation and Stability, Volume 153 Author(s): Anh T.N. Dao, Jun'ichi Shimokata, Kengo Takeuchi, Koyuru Nakayama, Toshiaki Taniike Recombinant spider silk has arisen as one of the most promising nature-derived building blocks owing to its extraordinary mechanical properties, while its instability against thermo-oxidative degradation becomes a major drawback toward industrial applications. Here, we have firstly implemented a high-throughput screening of antioxidants on the stabilization of recombinant spider silk at an elevated temperature. The usage of high-throughput chemiluminescence imaging has allowed us to screen antioxidants with a wide spectrum of molecular structures and quickly provided two good candidates to stabilize recombinant spider silk powder through an impregnation process: E310 and BHT. An accelerated aging has further proven that these antioxidants suppressed the thermo-oxidation of recombinant spider silk through scavenging the formed radical species and slowed down the formation of carbonyl groups as oxidation products. In addition, we have employed a solution mixing process to further improve the stabilization efficacy of the antioxidants and this method also extended our selection on effective antioxidants, including vitamin E, AO-30, AO-40, HP-10, and especially Irganox 1098. These screening results provide guidelines of selecting or even developing potential antioxidants for stabilizing protein materials.

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July 2018
Combined effects of Sepiolite and Cloisite 30B on morphology and properties of poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/polylactide blends
Publication date: July 2018
Source:Polymer Degradation and Stability, Volume 153 Author(s): Idris Zembouai, Mustapha Kaci, Lynda Zaidi, St
July 2018
Novel biocompatible PBS-based random copolymers containing PEG-like sequences for biomedical applications: From drug delivery to tissue engineering
Publication date: July 2018
Source:Polymer Degradation and Stability, Volume 153 Author(s): Martina Fabbri, Giulia Guidotti, Michelina Soccio, Nadia Lotti, Marco Govoni, Emanuele Giordano, Massimo Gazzano, Rita Gamberini, Bianca Rimini, Andrea Munari A series of random poly(butylene succinate)-based copolymers, (poly(butylene/triethylene succinate) (P(BSmTESn)), containing ether-oxygen atoms were successfully synthesized by melt polycondensation of succinic acid and 1,4-butanediol in the presence of triethylene glycol (TEG) (TEG content up to 40
July 2018
Fire retardant action of zinc phosphinate and polyamide 11 blend containing lignin as a carbon source
Publication date: July 2018
Source:Polymer Degradation and Stability, Volume 153 Author(s): Neeraj Mandlekar, Giulio Malucelli, Aurelie Cayla, Francois Rault, Stephane Giraud, Fabien Sala
July 2018
Improving flame retardancy of linear low-density polyethylene/nylon 6 blends via controlling localization of clay and intumescent flame-retardant
Publication date: July 2018
Source:Polymer Degradation and Stability, Volume 153 Author(s): Chang Lu, Xi-ping Gao, Da-hu Yao, Cheng-lin Cao, Yu-jing Luo Four processing methods were employed to control the localization of intumescent flame-retardant (IFR) and clay in linear low-density polyethylene/nylon 6 (LLDPE/PA6) blends and the effect of IFR and clay localization in blends on flame retardancy was investigated. The results obtained from the LOI and UL-94 tests showed that the flame retardancy in the blends with clay localization in the LLDPE phase was better than that of the blends with clay localization in the PA6 phase. Cone calorimeter test results demonstrated that IFR localization in the PA6 phase caused lower peak heat release rate (PHHR) than in the LLDPE phase. The combined effect resulted in the best flame retardancy exhibited in the blends with localization of IFR in the PA6 phase and clay in the LLDPE phase in comparison with the blends with other localization of IFR and clay. Scanning electron microscopy showed that clay localization in the LLDPE phase and IFR localization in the PA6 phase promoted the formation of an integrated and highly expansive char layer. It is believed the results of the study provide the references for optimizing the flame retardancy of polymer blends.
July 2018
Characterization of the chemical structure of vinyl ester resin in a climate chamber under different conditions of degradation
Publication date: July 2018
Source:Polymer Degradation and Stability, Volume 153 Author(s): Cristina Alia, Jos
July 2018
Flame retardancy of microcellular poly(lactic acid) foams prepared by supercritical CO2-assisted extrusion
Publication date: July 2018
Source:Polymer Degradation and Stability, Volume 153 Author(s): D
July 2018
On the degradation properties of electrospun fibers based on PLLA: The effect of a drug model modification
Publication date: July 2018
Source:Polymer Degradation and Stability, Volume 153 Author(s): Matteo Eleuteri, Laura Pastorino, Orietta Monticelli In this work, the features of electrospun fibers based on poly(l-lactide) (PLLA) containing drug model molecules, which were modified as to render them more dispersible in the polymer matrix and potentially capable of tuning the PLLA degradation, were investigated. Indeed, the above compounds, constituted by a pyrene terminal group attached to a short chain of poly(d-lactide) (Pyr-D) or PLLA (Pyr-L), were synthesized by employing 1-pyremethanol (Pyr-OH), a widely applied hydrophobic model drug, as the initiator of the ring opening polymerization (ROP) of L- or d-lactide. 1H NMR measurements allowed to calculate the oligomer molecular masses, which resulted to be in satisfactory agreement with the theoretical value. With the aim at verifying the influence of the synthesized compounds on the material final properties, electrospun fibers characterized by different compositions were prepared, that is fibers based on neat PLLA, PLLA with Pyr-OH, PLLA with Pyr-L, PLLA with Pyr-D and PLLA with Pyr-OH and Pyr-D, by adding an amounts of the various additives in order to obtain the same pyrene content. The morphological characterization, accomplished by means of FE-SEM, evidenced that the addition of the above compounds did not significantly influence the morphology of the fibers. Conversely, the fluorescent microscopy measurements demonstrated a different dispersion of the pyrene-based additives in the various samples, namely an aggregation of Pyr-OH and a homogeneous distribution of Pyr-L as well as Pyr-D. The fiber thermal properties were investigated by DSC measurements. In general, the annealing treatment, accomplished at 80
July 2018
Effects of chain-extending stabilizer on bioplastic poly(lactic acid)/polyamide blends compatibilized by reactive extrusion
Publication date: July 2018
Source:Polymer Degradation and Stability, Volume 153 Author(s): JeongIn Gug, James Soule, Bin Tan, Margaret J. Sobkowicz The immiscible bio-plastic blend of poly(lactic acid) (PLA) and polyamide11 (PA11 or Nylon11) was compatibilized, using a catalyzed the ester-amide interchange chemical reaction during reactive extrusion. The effects of screw configuration on mixing and reaction optimization were explored. It was found that effective mixing and minimized degradation were achieved when kneading elements were installed only near the die end of the extruder rather than near the beginning of the melt section. However, significant degradation of PLA could not be avoided during processing, which led to a decrease in mechanical strength of blend. To prevent the molecular weight reduction, tris(nonylphenyl) phosphite (TNPP) stabilizer was introduced to improve the thermal stability of PLA matrix. Improvement to both tensile strength and elongation were achieved in the resulting PLA/PA11/TsOH/TNPP blend.
July 2018
Thermooxidative degradation of crosslinked EVA/EPDM copolymers: Impact of Aluminium TriHydrate (ATH) filler incorporation
Publication date: July 2018
Source:Polymer Degradation and Stability, Volume 153 Author(s): Juliette Colombani, Ahmedou Sidi, Jean-Fran
July 2018
Getting a better insight into the chemistry of decomposition of complex flame retarded formulation: New insights using solid state NMR
Publication date: July 2018
Source:Polymer Degradation and Stability, Volume 153 Author(s): N. Hansupo, G. Tricot, S. Bellayer, P. Roussel, F. Samyn, S. Duquesne, M. Jimenez, M. Hollman, P. Catala, S. Bourbigot This paper aims at developing an innovative approach to characterize the char residue of an intumescent coating obtained after a UL1709 furnace test. The intumescent formulation is based on an epoxy resin and contains numerous additives including zinc borate, ammonium polyphosphate and silicate fibers. The purpose is to characterize the numerous reactions that can occur upon burning using crossed methods including Electron Probe Micro-Analysis (EPMA), X-ray diffraction (XRD) and 1D/2D solid state Nuclear Magnetic Resonance (NMR). In particular, it emphasizes the potential of the advanced NMR technique namely two-dimensional Dipolar Heteronuclear Multiple Quantum Correlation (2D D-HMQC) NMR. As a result, EPMA evidenced that B/P and B/Si are located in the same domain suggesting the formation of boron-phosphorus and/or boron-silicone containing compounds on the sample surface. H3BO3 was identified by XRD as a main crystalline specie, additional species (e.g. SiO2, Zn4O(BO2)6) were also identified. The borate, silicate and phosphate chemical species were then characterized using 1D NMR but no definitive assignments could be given. To specify those assignments, 2D D-HMQC NMR was performed and the formation of amorphous borophosphates and borosilicates was evidenced emphasizing the chemical reactivity between the ingredients of the formulation. It was suggested that these species allow reinforcing the char and improving the fire protective properties of the coatings. This work highlights the particular interest of advanced NMR technique, which provides unique information on the characterization of intumescent char.

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July 2018
Synergistic effects of synthetic phosphonium sulfonates with expandable graphite on flame retardancy for EVA rubber blends
Publication date: July 2018
Source:Polymer Degradation and Stability, Volume 153 Author(s): Shijie Hou, Yong Jian Zhang, Pingkai Jiang Synergistic effects of synthetic phosphonium sulfonates (PhSs) bearing different groups with expandable graphite (EG) on flame retardancy properties in poly(ethylene-co-vinyl acetate) (EVA) rubber blends have been studied by limiting oxygen index (LOI), UL-94 test, cone calorimeter test (CCT), and thermogravimetric analysis (TGA). The EVA/EG/PhS composites revealed excellent flame retardancies. Upon adding 2.5
July 2018
Diffusion and hydrolysis effects during water aging on an epoxy-anhydride system
Publication date: July 2018
Source:Polymer Degradation and Stability, Volume 153 Author(s): Guillermina Capiel, Julieta Uicich, Diana Fasce, Pablo E. Montemartini Hydrothermal aging of an epoxy-anhydride network has been studied by means of gravimetric analysis, Fourier transform infrared spectroscopy (FTIR) and modulated differential scanning calorimetry (MDSC). The long-term aging results revealed a fourth stage mechanism in which an initial short diffusional period is followed by the hydrolysis of the ester groups. Degraded materials showed two values of glass transition temperature suggesting a heterogeneous process. Hydrolysis undergoes in preferential sites due to the catalytic effect of the carboxyl acids formed during the chemical degradation. Domains with low crosslinking density and high mobility are formed. At long degradation time, samples presented a unique glass transition temperature around 50
July 2018
Effects of ZnO quantum dots on the photostability of acrylate photopolymers used as recording materials
Publication date: July 2018
Source:Polymer Degradation and Stability, Volume 153 Author(s): Georgia G. Goourey, Pascal Wong-Wah-Chung, Lavinia Balan, Ya
July 2018
Radiation stability of silicon-organic varnish modified with nanoparticles
Publication date: July 2018
Source:Polymer Degradation and Stability, Volume 153 Author(s): M.M. Mikhailov, V.V. Neshchimenko, A.V. Grigorevskiy, A.N. Sokolovskiy, A.S. Bakhtaulova, I.S. Vaschenkov An effect of SiO2 nanoparticles modification on spectra and integral absorption coefficient of silicon-organic varnish KO-859 before and after 30
July 2018
A reactive phosphorus-containing polyol incorporated into flexible polyurethane foam: Self-extinguishing behavior and mechanism
Publication date: July 2018
Source:Polymer Degradation and Stability, Volume 153 Author(s): Wen-Hui Rao, Zong-Min Zhu, Shui-Xiu Wang, Ting Wang, Yi Tan, Wang Liao, Hai-Bo Zhao, Yu-Zhong Wang A novel liquid phosphorus-containing polyol named as PDEO was prepared via reactions between ethylene glycol and phenylphosphonic dichloride. PDEO reacts with the -NCO-terminated prepolymers and forms urethane linkages in the chain extending reaction step, thus, it was used to prepare inherently flame-retardant flexible polyurethane foams (FPUFs). The structure and properties of flame-retardant FPUFs were characterized by scanning electron microscopy (SEM), tensile measurements, limiting oxygen index (LOI), vertical burning tests, cone calorimeter tests and thermogravimetric analysis (TGA). The vertical burning test demonstrated that fire extinguished instantly after the withdrawn of the pilot flame, while the PDEO loading was only 10
July 2018
Facile synthesis and characterization of activated star-shaped itaconic acid based thermosetting resins
Publication date: July 2018
Source:Polymer Degradation and Stability, Volume 153 Author(s): Arash Jahandideh, Nima Esmaeili, Kasiviswanathan Muthukumarappan Novel star-shaped thermosetting resins were synthesized by condensation-reaction of itaconic acid and glycerol, followed by treatment of the oligomers, by methanol and allyl alcohol. Employing 1H and 13C NMR and FT-IR, the chemical structures of the resins were studied. The thermomechanical properties were evaluated by Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analysis (DMA). Viscometry and thermogravimetric analyses (TGA) were also employed to study the rheological and thermal properties of samples. The viscosity of the methanol-treated resin was 4.2
July 2018
High-performance flame retardant epoxy resin based on a bi-group molecule containing phosphaphenanthrene and borate groups
Publication date: July 2018
Source:Polymer Degradation and Stability, Volume 153 Author(s): Shuo Tang, Lijun Qian, Yong Qiu, Yuping Dong A flame retardant named ODOPB-Borate constructed by phosphaphenanthrene (DOPO) and borate groups was synthesized via esterification reaction between boric acid and 10-(2,5-dihydroxyphenyl)-10-H-9-oxa-10-phosphaphenanthrene-10-oxide (ODOPB). The molecular structure of ODOPB-Borate was characterized and verified. To research the group synergistic effect of phosphaphenanthrene and borate groups, ODOPB-Borate was incorporated into epoxy resin, diglycidyl ether of bisphenol-A (DGEBA), cured by 4,4-diamino-diphenyl sulfone (DDS). ODOPB-Borate increased the LOI and particularly improved the UL94 classification of epoxy resin thermosets, and also reduced the heat release of epoxy thermosets. Further, the decrease of total mass loss value of thermoset containing ODOPB-Borate revealed that ODOPB-Borate facilitated the EP composites to form more residue. The analyzed pyrolysis route of ODOPB-Borate revealed that ODOPB part mainly exerted quenching effect in gas phase and the borate part mostly remained in condensed phase and promoted charring effect and smoke suppressing effect. The synergistic effect from phosphaphenanthrene and borate groups endowed epoxy resins with flame retardancy. Moreover, ODOPB-Borate also increased the glass transition temperature and impact strength of epoxy resin.
July 2018
Identifying the role of the acidic comonomer in poly(acrylonitrile-co-itaconic acid) during stabilization process through low temperature electron beam irradiation
Publication date: July 2018
Source:Polymer Degradation and Stability, Volume 153 Author(s): Dong Won Cho, Ravindra V. Ghorpade, Sung Chul Hong The stabilization behavior of poly (acrylonitrile-co-itaconic acid) (PAI) by using electron beam irradiation (EBI) was investigated to identify the role of itaconic acid (IA). EBI was employed as a tool to generate radicals, which induced a cold stabilization reaction at room temperature and excluded ionic and thermally induced radical-mediated stabilization reactions. Fourier transform infrared spectroscopy was employed to quantitatively track the structural evolution of the PAI during stabilization. The stabilization reactions of the PAIs successfully progressed with higher EBI dosages at room temperature. More efficient cyclization reactions were observed for the PAIs with increased amounts of IA, because of the increased amorphous regions of the PAIs with a higher level of IA. The extents of the cyclization values of the PAIs normalized to their crystallinity values were similar to each other regardless of the IA contents, indicating the absence of an ionic initiation mechanism of IA at room temperature. In addition, the incorporation of IA units in PAIs increased the polarity and oxophilicity of the PAIs, thereby inducing facilitated oxygen uptake reactions, as evidenced by the high concentrations of conjugated carbonyl groups in the stabilized structures.

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July 2018
Fire resistant polyphenols based on chemical modification of bio-derived tannic acid
Publication date: July 2018
Source:Polymer Degradation and Stability, Volume 153 Author(s): Zhiyu Xia, Weeradech Kiratitanavit, Patrick Facendola, Sammaiah Thota, Shiran Yu, Jayant Kumar, Ravi Mosurkal, Ramaswamy Nagarajan Utilization of renewable materials for the development of safer and nontoxic flame retardants has been of interest from environmental safety and sustainability perspective. Tannic acid (TA) is an abundantly available bio-based polyphenol that exhibits good intumescence and char forming characteristics upon being subjected to heat. Intumescence and char formation are important prerequisites for certain types of effective flame retardant (FR) additives. However, the potential for utilizing TA as an FR has been limited by its poor thermal stability. A single step chemical modification process that overcomes the limitations of TA while allowing the utilization of its beneficial properties is reported here. TA was crosslinked using interfacial polycondensation with terephthaloyl chloride to yield tannic acid terephthalate (TAT). The complex structure of TAT necessitated the synthesis of several model compounds based on methyl gallate (MG) to facilitate the complete structural characterization of TAT using FTIR and 1H NMR. TAT is thermally stable up to 230
July 2018
A non-destructive method for crack quantification in photovoltaic backsheets under accelerated and real-world exposures
Publication date: July 2018
Source:Polymer Degradation and Stability, Volume 153 Author(s): Addison G. Klinke, Abdulkerim Gok, Silas I. Ifeanyi, Laura S. Bruckman The long-term durability of photovoltaic modules is paramount for the continued growth of the industry. Polymer backsheets are of particular concern since they provide electrical insulation and an environmental barrier. In this study, 23 freestanding, multilayer backsheets with nine unique material combinations underwent four different weathering exposures under accelerated and real-world conditions. Besides changes in color and gloss, the induced degradation included parallel or mudflat cracks on 11 backsheets, sometimes in combination with delamination or blistering. Similar degradation has been observed in previous studies and is concerning since cracks compromise the mechanical integrity and electrical safety of backsheets. Quantitative parameters are desirable to reliably classify categories of cracks and supply unbiased features for statistical analysis in predictive lifetime models. We developed an analysis technique that utilizes surface profilometry data to quantify the depth, width, area, spacing, and number of cracks. Parameters are automatically extracted from the raw data by an algorithm running on a high performance distributed computing cluster. Our algorithm excelled at characterizing parallel cracks with minimal de-adhesion, and only an estimated 4% of crack detections were false positives. The addition of humidity and temperature variation formed up to three times as many cracks on a photodose basis compared to dry, constant temperature exposures. Cracks in real-world and accelerated exposures propagated to similar depths with equivalent photodoses; however, the number of cracks formed in accelerated exposures was far greater on a photodose basis. Of samples that cracked, the best performing backsheet configuration was polyvinyl fluoride/poly (ethylene-terephthalate)/polyethylene (PVF/PET/PE) while the least durable was PET/PET/ethylene-vinyl acetate. None of the six PVF/PET/PVF backsheets cracked in any of the exposures.
July 2018
Effect of crystallinity on CF/PPS performance under weather exposure: Moisture, salt fog and UV radiation
Publication date: July 2018
Source:Polymer Degradation and Stability, Volume 153 Author(s): Natassia L. Batista, Mirabel C. Rezende, Edson C. Botelho The crystalline content of a composite can affect its performance under environmental conditions. The objective of this study is to evaluate the influence of the crystallinity degree of CF/PPS composites to hygrothermal, salt fog and ultraviolet/condensation conditioning. DSC and DMA results, and Young's modulus and ILSS values were used to evaluate the changes in the thermal and mechanical properties of CF/PPS composites after conditioning. The crystallinity degree showed to affect the water uptake and the severity of degradation. Differences up to 40% were found among the mechanical properties values depending on the crystallinity. In the hygrothermal and salt fog conditioning the least crystalline laminates were mostly degraded. In contrast, in the ultraviolet/condensation conditioning the composites with the highest crystalline contents were more affected.
July 2018
Hydrolytic degradation of d-mannitol-based polyurethanes
Publication date: July 2018
Source:Polymer Degradation and Stability, Volume 153 Author(s): Luc

Poly(hexamethylene 2,5-furandicarboxylate) copolyesters containing phosphorus: Synthesis, crystallization behavior, thermal, mechanical and flame retardant properties
Publication date: July 2018
Source:Polymer Degradation and Stability, Volume 153 Author(s): Guoqiang Wang, Min Jiang, Qiang Zhang, Rui Wang, Xiaoling Qu, Guangyuan Zhou A series of phosphorus-containing poly (hexamethylene 2,5-furandicarboxylate)s (PHFCs) were synthesized from available biobased 2,5-furandicarboxylic acid (FDCA), 1,6-hexanediol (HDO), and 2-carboxyethyl (phenyl)phosphinic acid (CEPPA). Microstructure, molecular weight and its distribution, crystallization behavior, thermal, mechanical and flame retardant properties were characterized. Moreover, the effects of composition on various properties were investigated systematically. All PHFCs exhibited the excellent thermal stability. Glass transition temperature of PHFC slightly decreased with the increasing of CEPPA. Furthermore, nano-TiO2 not only improved the molten drops phenomenon, but also increased the crystallization rate. The limiting oxygen index of PHFC with 10
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