Search

High performance thermoplastic elastomers based on ethylene-vinyl acetate rubber (EVM) and ternary polyamide copolymer (tPA) were prepared through a dynamic vulcanization process in the presence of dicumyl peroxide (DCP). The morphology, crystallization, and mechanical properties of the EVM/tPA blends were studied. A phase transition of EVM/tPA blend was observed at a weight ratio of 60/40. The presence of EVM increased the melting enthalpy at the high temperature of tPA, ascribing to the heterogeneous nucleating effect of EVM. The tensile strength of EVM/tPA (70/30) blends was increased up to 20.5 MPa as the DCP concentration increased to 3.5 phr, whereas the elongation at break of the blends kept decreasing as the DCP concentration increased. The addition of ethylene-acrylic acid copolymer (EAA) or maleic anhydride-grafted EVM (EVM-g-MAH) to the EVM/tPA blends both induced finer dispersion of the EVM particles in the tPA phase and improvement in the tensile strength and elongation at break of the blends, which were ascribed to the compatibilization of EAA or EVM-g-MAH. Finally, a high performance EVM/tPA (70/30) thermoplastic elastomer with Shore A hardness of 75, tensile strength of 24 MPa, elongation at break of 361%, and set at break of 20% was obtained by adding 5 wt % of EVM-g-MAH and 3.5 phr DCP. It has great potential in automotive and oil pipeline applications. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Poly(vinyl chloride) (PVC)/acrylonitrile–butadiene rubber (NBR) were mixed with multiwalled carbon nanotubes (MWCNTs) and silicon carbide (SiC) to prepare microwave-absorbing composites. The complex permittivity, direct-current (dc) conductivity, microwave-absorbing performance, morphology, and mechanical properties of the composites were studied. The real and imaginary parts of the permittivity of the composites increased with increasing MWCNT content. The premixing of the MWCNTs with PVC was more beneficial to the dispersion of MWCNTs; this led to a higher dc conductivity and permittivity and better microwave-absorbing performance than the premixing of MWCNTs with NBR for the PVC/NBR/MWCNT composites. The PVC/NBR/MWCNT composites had a minimum reflection loss (RLmin) of −49.5 dB at the optimum thickness of 1.96 mm. The efficient microwave absorption of the PVC/NBR/MWCNT composites was due to a high dielectric loss and moderate permittivity. The incorporation of SiC into the PVC/NBR/MWCNT composites increased the real and imaginary parts of permittivity of the composites. When the SiC content was 70 phr, RLmin decreased to −34.9 dB at a thickness of 3 mm. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

A novel organic–inorganic hybrid of epoxycyclohexyl polyhedral oligomeric silsesquioxane (e-POSS)–grafted carboxylic methoxypolyethylene glycols (mPEG-COOH), that is, a POSS-mPEG graftomer, was synthesized. The grafting reaction of e-POSS and mPEG-COOH was characterized by Fourier transform infrared (FTIR) and 1H-NMR spectroscopy. Then the graftomer was used to develop new composite solid polymer electrolyte (SPE) films with a carboxylated nitrile rubber–epoxidized natural rubber (XNBR-ENR) self-crosslinked blend system as a dual-phase polymer matrix. The self-crosslinked reaction of the XNBR-ENR matrix was investigated using ATR-FTIR. The morphology of the SPE films and the distribution of lithium salt were investigated using field emission scanning electron microscopy and X-ray diffraction, and the result illustrated that the addition of POSS-mPEG could promote and accelerate the dissociation of LiClO4. The best effect within the range of this study was achieved when 25 phr POSS-mPEG was involved. The differential scanning calorimetry analysis proved that the glass-transition temperature of the composite SPE films was reduced with the increase of POSS-mPEG. The ionic conductivity of the composite SPE films was investigated by electrochemical impedance spectroscopy. The highest ionic conductivity in this study of 2.57 × 10−5 S cm−1 was obtained with 25 phr POSS-mPEG loading. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44460.

The effects of processing temperature and bis-[γ-(triethoxysilyl)-propyl]-tetrasulfide (Si69) on crystallization, morphology, and mechanical properties of styrene-butadiene rubber (SBR)/trans-1,4-polyisoprene (TPI) vulcanizate are investigated. The crystallinity and crystalline melting temperature (Tm) of TPI in the vulcanizates with TPI/silica/(Si69) pre-mixed at 150 °C are much lower than that pre-mixed at 80 °C. At the same pre-mixing temperature, the presence of 1 phr Si69 leads to a decreased crystallinity and Tm. The TPI domains with phase size of about 1 μm and silica are well dispersed in the vulcanizate, and TPI crystals get smaller in size and less in amount by pre-mixing TPI, silica and Si69 at 150 °C. The vulcanizates with TPI/silica/(Si69) pre-mixed at 150 °C have decreased tensile strength and modulus at a given extension than that pre-mixed at 80 °C. At the same pre-mixing temperature, the tensile strength and modulus of the vulcanizate increase with the addition of 1 phr Si69. The crystallinity of TPI component in SBR/TPI vulcanizate is effectively controlled by changing processing temperature and adding Si69, which is important for theoretical research and practical application of TPI. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44395.

Commercial brominated poly(isobutylene-co-isoprene) (BIIR) rubber has been directly used for the initiation of atom transfer radical polymerization (ATRP) by utilizing the allylic bromine atoms on the macromolecular chains of BIIR. The graft copolymerization of methyl methacrylate (MMA) from the backbone of BIIR which was used as a macroinitiator was carried out in xylene at 85 °C with CuBr/N,N,N′,N″,N″-pentamethyldiethylenetriamine as a catalytic complex. The polymerization conditions were optimized by adjusting the catalyst and monomer concentration to reach a higher monomer conversion and meanwhile suppress macroscopic gelation during the polymerization process. This copolymerization followed a first-order kinetic behavior with respect to the monomer concentration, and the number-average molecular weight of the grafted poly(methyl methacrylate) (PMMA) increased with reaction time. The resultant BIIR-graft-PMMA copolymers showed phase separation morphology as characterized by atomic force microscopy, and the presence of PMMA phase increased the polarity of the BIIR copolymers. This study demonstrated the feasibility of using commercial BIIR polymer directly as a macromolecular initiator for ATRP reactions, which opens more possibilities for BIIR modifications for wider applications. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43408.

In this work, Eu(Pht)3Phen/SBA-15 hybrids were prepared by solution mixing and their morphologies and structures were characterized by X-ray diffraction (XRD), scanning electronic microscopy (SEM), nitrogen adsorption–desorption and transmission electronic microscopy (TEM). The results showed that Eu(Pht)3Phen was successfully incorporated into the channels and assembled onto the surface of SBA-15 and the long range ordered structure of SBA-15 was preserved. The silicone rubber composites with Eu(Pht)3Phen/SBA-15 hybrids were obtained by mechanical blending, and their morphologies and photoluminescence properties were studied. The results showed that the photoluminescence intensities of the composites with the hybrids increased as the content of the hybrids increased. The composite with the hybrids showed higher photoluminescence intensity and longer lifetime compared to the silicone rubber compounded with Eu(Pht)3Phen (Eu(Pht)3Phen/silicone rubber composite), Eu(Pht)3Phen and SBA-15 ([Eu(Pht)3Phen+SBA-15]/silicone rubber composite). Judd-Ofelt theory was used to investigate the local environment of Eu3+ ions in the silicone rubber composites. The photoluminescence quantum efficiency of the silicone rubber composite with Eu(Pht)3Phen/SBA-15 hybrids was calculated to be 31.0%, higher than that of Eu(Pht)3Phen/silicone rubber composite (26.4%) and [Eu(Pht)3Phen+SBA-15]/silicone rubber composite (25.4%). The enhancement in photoluminescence intensity and increase in lifetime and photoluminescence quantum efficiency could be attributed to the rigid structure of SBA-15 which reduced the nonradiative transition rate and the improvement of the dispersion of the hybrids in the composites. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

In this study, a novel Schiff base of melamine used as flame-retardant curing agent for epoxy resins, was synthesized via condensation reaction of 4-hydroxybenzaldehyde with melamine, followed by the addition of 9,10-dihydro-9-oxa-10-phosphaphen-anthrene 10-oxide (DOPO) to the resulting imine linkage. The structure of DOPO-containing melamine Schiff base (P-MSB) was characterized by Fourier transformed infrared spectroscopy, 1H-nuclear magnetic resonance (1H-NMR) and 31P-NMR. The compound (P-MSB) was used as a reactive flame retardant in o-cresol formaldehyde novolac epoxy resin (CNE) to prepare flame-retardant epoxy resins for electronic application. The thermal and flame-retardant properties of the epoxy resins cured by various equivalent ratios phenol formaldehyde novolac (PN) and P-MSB were investigated by the nonisothermal differential scanning calorimetry, the thermogravimetric analysis, and limiting oxygen index test. The obtained results showed that the cured epoxy resins possessed high Tg (165°C) and good thermal stability (T5%, 321°C). Moreover, the P-MSB/CNE systems exhibited higher limiting oxygen index (35) and more char was maintained in P-MSB/CNE systems than that in PN/CNE system and the effective synergism of phosphorus–nitrogen indicated their excellent flame retardancy. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Based on amine-terminated butadiene-acrylonitrile copolymer chemically crosslinked by epoxycyclohexyl polyhedral oligomeric silsesquioxane (POSS), a novel gel polymer electrolyte (GPE) were prepared by introducing one ionic liquid and LiClO4 into the polymer framework. Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and X-ray diffraction analysis confirmed the interaction between the ionic liquid and LiClO4, and this interaction contributes to dissolving LiClO4 salt and increasing the ionic conductivity of GPE. Less content of POSS leads to higher ionic conductivities but lower gel content and modulus. The maximum ionic conductivity of 2.0 × 10−4 S cm−1 (30°C) was achieved and an Arrhenius-type relationship between ionic conductivities and temperatures could be detected over the investigated temperature range. The generated GPE exhibited good electrochemical stability to 4 V from cyclic voltammogram tests, which made this kind of GPE a promising candidate for rechargeable lithium batteries. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Two novel flame-retardant curing agents for epoxy resins, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO)-containing 4-[(phenylamino)methyl]phenol (P-Ph) and DOPO-containing Mannich-type bases (P-DDS-Ph), were synthesized by the condensation of 4-hydroxybenzaldehyde with 4-aminophenol and DDS, respectively, followed by the addition of DOPO to the resulting imine linkage. Chemical structures of these materials were characterized with FTIR, 1H-NMR spectra, 31P-NMR spectra, and elemental analysis. The thermal properties and flame retardancy of o-cresol novolac epoxy resin (CNE) cured with different contents of the phosphorus-containing compounds were investigated by nonisothermal differential scanning calorimetry, thermogravimetric analysis, and limiting oxygen index (LOI). The obtained results showed that more char was formed while containing lower contents of the phosphorus-containing compounds in the P-Ph/CNE and P-DDS-Ph/CNE indicating their excellent flame retardancy. Moreover, the P-DDS-Ph/CNE exhibited higher Tg (224°C) and better thermal stability (T10%, 330°C) than that of P-Ph/CNE. Therefore, the developed P-DDS-Ph/CNE may be potentially used as environmentally preferable products in electronic fields. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

A new organic–inorganic hybrid material was prepared through reactive blending of hydrogenated carboxylated nitrile rubber (HXNBR) with epoxycyclohexyl polyhedral oligomeric silsesquioxanes (epoxycyclohexyl POSS). The structure of the composite was characterized by Fourier transform infrared spectroscopy (FTIR) and solid-state 13C Nuclear Magnetic Resonance spectra (solid-state 13C-NMR). The differential scanning calorimetry (DSC) at different heating rates was conducted to investigate the curing kinetics. A single overall curing process by an nth-order function (1 − α)n was considered, and multiple-heating-rate models (Kissinger, Flynn–Wall–Ozawa, and Crane methods) and the single-heating-rate model were employed. The apparent activation energy (Ea) obtained showed dependence on the POSS content and the heating rate (β). The overall reaction order n was practically constant and close to 1. The isoconversion Flynn–Wall–Ozawa method was also performed and fit well in the study. With the single-heating-rate model, the average Ea for the compound with a certain POSS content, 66.90–104.13 kJ/mol was greater than that obtained with Kissinger and Flynn–Wall–Ozawa methods. Furthermore, the calculated reaction rate (dα/dt) versus temperature curves fit with the experimental data. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

The toughness of three different elastomer-toughened nylon 1010 blends was investigated via standard notched Izod impact test and single edge notched three-point bending test. The toughness of nylon 1010 blends varies much with different elastomer types and components. All three kinds of nylon/elastomer/maleated-elastomer blends showed high impact strength (over 50 kJ m−2) as long as at appropriate blending ratios. With increasing maleated elastomer content, brittle-ductile transition was observed for all three kinds of elastomer-toughened nylon 1010 blends. The number average dispersed particle size (dn) of ethylene-1-octene copolymers or ethylene-vinyl acetate copolymers toughened nylon 1010 blends significantly decreased from over 1 to 0.1 μm with increasing corresponding maleated elastomer content. Investigation on the fracture toughness showed the dissipative energy density gradually increased with decreasing dn, while the limited specific fracture energy increased with increasing dn when dn was below 1 μm and then sharply decreased with further increasing dn. The energy consumed in the outer plastic zone was the main part of the whole energy dissipated during the fracture process. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Ethylene–vinyl acetate rubber (EVM) vulcanizates with excellent mechanical properties were obtained with magnesium hydroxides (MH) and methacrylic acid (MAA). MAA significantly improved the mechanical properties of the MH-filled EVM vulcanizates. The tensile strength, Shore A hardness, and tensile set modulus of the EVM vulcanizates significantly increased with increasing MAA content. The tensile strength of the MH-filled EVM vulcanizates increased from 12.3 to 18.5 MPa after the addition of 2.5 phr MAA when the MH content was fixed at 60 phr. The gross crosslink density and ionic crosslink density increased with increasing MAA content. The glass-transition temperature and tan δ slightly decreased with increasing MAA content. Morphological study showed that MAA obviously improved the dispersion of the MH particles in the EVM matrix. The thermal stability of the EVM vulcanizates was obviously enhanced after the addition of MAA. Fourier transform infrared analysis indicated that MAA reacted with MH to form magnesium methacrylates, and there was a polymerization of MAA during the curing process in the existence of peroxide. An ionic crosslink bond was thought to be formed on the surface of the MH aggregates; this resulted in a possible structure where MH aggregates were considered as crosslink points. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Synergistic effects of the natural clays unexfoliated vermiculite (VMT), exfoliated vermiculate (EVMT), and montmorillonite (MMT) on the intumescent flame retardance of polypropylene were investigated systematically with the usual fire testing methods. The limiting oxygen index (LOI) of flame-retardant polypropylene (FRPP) filled with 30 wt % intumescent flame retardants (IFRs) composed of ammonium polyphosphate and pentaerythritol were increased from 30 to 33 vol % for VMT and MMT and to 36 vol % for EVMT when 1 wt % IFR was substituted for clay. The synergistic effectivities calculated on the basis of increases in the LOI values were 1.4 for VMT, 1.3 for MMT, and 1.6 for EVMT. Cone calorimetry also revealed the existence of a synergistic effect. EVMT had the best performance for lowering the peak values of the heat release rate and smoke production rate. The thermogravimetric analysis results show that EVMT had the best performance for increasing the char residue of FRPP higher than 650°C compared with VMT and MMT. The high content of iron and the small particle size of EVMT may have been responsible for its high synergistic effect at a low filling level. No remarkable variations of the diffraction peaks were observed in the X-ray diffraction patterns of the original clay and the clay in FRPP. All of the formulations, with or without clay, exhibited small variations in the mechanical properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

A new type of epoxy resin curing agent, containing pendant phenol functions, was synthesized by the free-radical copolymerization of N-(4-hydroxyphenyl) maleimide with dicyclopentadiene (DCPD) monomer in the presence of a radical initiator. The chemical structure was characterized with Fourier transform infrared spectroscopy and nuclear magnetic resonance. The molecular weight of the new curing agent was determined by gel permeation chromatography. The activity and activation energy of this new curing agent with o-cresol formaldehyde novolac epoxy (CNE) was investigated with a nonisothermal differential scanning calorimetry technique at different heating rates. The thermal properties of the cured polymers were evaluated with thermogravimetric analysis, and the results exhibit good thermal stability. In addition, this new curing agent with CNE showed low moisture absorption because of the hydrophobic nature of the DCPD structure. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Flame retardant polycarbonate (FRPC) with 0.2 wt % additives of potassium perfluorbutane sulfonate and polydimethylsiloxane was found to achieve V-0 rate at 1.6 mm thickness without significantly affecting the mechanical properties of PC. Condensed aromatic bonds with a small amount of SiO bonds were found in the UL-94 burning residues tested by FTIR spectra. A compact char layer with cavities inside was formed on the surface of the sample during the rapid decomposition of FRPC, and the concentration of Si was found to be much higher inside the surface of the char layer than that outside the surface analyzed by SEM-EDX, which was related to the synergistic effects of the two flame retardants of PPFBS and PDMS. A schematic diagram was designed to describe the mechanism of the FRPC. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Ethylene-vinyl acetate rubber (EVM) vulcanizates cured by dicumyl peroxide (DCP) with excellent mechanical properties were obtained by adding superfluous magnesium hydroxides (MH)/methacrylic acid (MAA). Different factors such as the DCP content and MH content were investigated to reveal their effects on the properties of the MH/MAA-filled EVM vulcanizates. The formulation of DCP of 2 phr, MH of 60 phr, and MAA of 5 phr is recommended for the EVM vulcanizates with excellent mechanical properties. The stress relaxation and stress softening behavior of MH/MAA-filled EVM vulcanizates were studied. The stress relaxation and stress softening became faster and more obvious with increasing MH content. The hot air aging resistance of EVM vulcanizates filled with different fillers such as silica and high abrasion furnace were compared, and the MH/MAA-filled EVM vulcanizates had the best aging resistance at 40-phr filler content. The MH/MAA-filled EVM vulcanizates had excellent flame retardancy due to the high MH content. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Styrene–maleic anhydride copolymer (SMA) with higher MA content (21.8 wt %) than reported SMA (mostly 8 wt %) was used as a compatibilizer for poly(2,6-dimethyl-1,4-phenylene oxide) (PPO)/polyamide 6 (PA6) blends by in situ formed PA-g-SMA during melt processing. The tensile strength and flexural strength of PPO/PA blends were greatly increased by the addition of SMA. The morphology of PPO/PA/SMA (30/70/variable) was investigated by scanning electron microscopy, and the addition of SMA led to a significant decrease in the particle size of the dispersed PPO phase. Melting and crystallization of PPO/PA/SMA blends were studied by differential scanning calorimetry, and the results showed that the addition of SMA could improve the compatibility between PPO and PA. The in situ reaction between PA and SMA was confirmed by Fourier transform infrared analysis. SMA was an effective compatibilizer for PPO/PA blends, and its compatibilization mechanism was discussed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Solid polymer electrolytes based on acrylonitrile-butadiene rubber (NBR) and LiClO4 were prepared and their conductivity was evaluated. The effect of nitrile group CN/LiClO4 mole ratio on the conductivity was investigated. The maximum conductivity of 1.21 × 10−4 S cm−1 (20°C) was achieved in the NBR/LiClO4 composite at the CN/LiClO4 mole ratio of 1/2.5, which was in accordance with the strongest coordination between CN and Li+ indicated by Fourier transform infrared spectrometry measurement. The conductivity was further increased by two to three times when 30 phr epoxy resin was introduced into NBR, and the conductivity could retain around the maximum value with the CN/LiClO4 mole ratio ranged from 1/2.5 to 1/3.5, while the conductivity of NBR/LiClO4 composite existed a decrease in the same range. Field emission scanning electron microscopy and atomic force microscopy characterization showed that epoxy resin significantly improved the dispersion of LiClO4, leading to better surface smoothness of NBR/epoxy resin/LiClO4 composite film and contributing to the increase of ionic conductivity. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Poly(2,6-dimethyl-1,4-phenylene oxide)/polyamide 6 (PPO/PA6 30/70) blends were impact modified by addition of three kinds of maleated polystyrene-based copolymers, i.e., maleated styrene-ethylene-butylene-styrene copolymer (SEBS-g-MA), maleated methyl methacrylate-butadiene-styrene copolymer (MBS-g-MA), and maleated acrylonitrile-butadiene-styrene copolymer (ABS-g-MA). The mechanical properties, morphology and rheological behavior of the impact modified PPO/PA6 blends were investigated. The selective location of the maleated copolymers in one phase or at interface accounted for the different toughening effects of the maleated copolymer, which is closely related to their molecular structure and composition. SEBS-g-MA was uniformly dispersed in PPO phase and greatly toughened PPO/PA6 blends even at low temperature. MBS-g-MA particles were mainly dispersed in the PA6 phase and around the PPO phase, resulting in a significant enhancement of the notched Izod impact strength of PPO/PA6 blends from 45 J/m to 281 J/m at the MBS-g-MA content of 20 phr. In comparison, the ABS-g-MA was mainly dispersed in PA6 phase without much influencing the original mechanical properties of the PPO/PA6 blend. The different molecule structure and selective location of the maleated copolymers in the blends were reflected by the change of rheological behavior as well.

The copolymer of pyrrole and aniline, poly(pyrrole-co-aniline), has been prepared by chemical oxidation of corresponding monomer mixtures with ammonium peroxysulfate. Techniques of FTIR, SEM-EDS, and BET surface area measurement were used to characterize the structure and morphology of the copolymer. The electrochemical properties of the copolymer were investigated by cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. The results indicated that poly(pyrrole-co-aniline) was about 100–300 nm in diameter and showed better electrochemical capacitive performance than polypyrrole and polyaniline. The specific capacitance of the copolymer electrode was 827 F/g at a current of 8 mA/cm2 in 1 mol/L Na2SO4 electrolyte. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

The mechanical properties, flame retardancy, hot-air ageing, and hot-oil ageing resistance of ethylene-vinyl acetate rubber (EVM)/hydrogenated nitrile-butadiene rubber (HNBR)/magnesium hydroxide (MH) composites were studied. With increasing HNBR fraction, elongation at break and tear strength of the EVM/HNBR/MH composites increased, whereas the limited oxygen index and Shore A hardness decreased slightly. Hot-air ageing resistance and hot-oil ageing resistance of the composites became better with increasing HNBR fraction. Thermal gravimetric analysis results demonstrated that the presence of MH and low HNBR fraction could improve the thermal stability of the composites. Differential scanning calorimeter revealed that the glass transition temperature (Tg) of the composites shifted toward low temperatures with increasing HNBR fraction, which was also confirmed by dynamic mechanical thermal analysis. Atomic force microscope images showed MH has a small particle size and good dispersion in the composites with high HNBR fraction. The flame retardancy, extremely good hot-oil ageing, and hot-air ageing resistance combined with good mechanical properties performance in a wide temperature range (−30°C to 150°C) make the EVM/HNBR/MH composites ideal for cables application. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Poly(butylene succinate-co-adipate) (PBSA) and two types of SiO2 (hydrophilic or hydrophobic) were used to modify poly(L-lactic acid) (PLLA). The mechanical properties, rheological and thermal behavior, phase morphology, and thermal stability of PLLA/PBSA/SiO2 composites were investigated. The impact strength, flexural strength, and modulus of PLLA/PBSA blends increased after the addition of hydrophobic SiO2 without decreasing the elongation at break, and the elongation at break monotonically decreased with increasing hydrophilic SiO2 content. The melt elasticity and viscosity of the PLLA/PBSA blend increased with the addition of SiO2. The hydrophilic SiO2 was encapsulated by the dispersed PBSA phase in the composites, which led to the formation of a core–shell structure, whereas the hydrophobic SiO2 was more uniformly dispersed and mainly located in the PLLA matrix, which was desirable for the optimum reinforcement of the PLLA/PBSA blend. The thermogravimetric analysis results show that the addition of the two types of SiO2 increased the initial decomposition temperature and activation energy and consequently retarded the thermal degradation of PLLA/PBSA. The retardation of degradation was prominent with the addition of hydrophobic SiO2. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Octavinyl POSS (vPOSS) and epoxycyclohexyl POSS (ePOSS) were separately incorporated into the poly(lactic acid)/poly(butylene succinate-co-adipate) (PLA/PBSA) blend by melt mixing. Field emission scanning electron microscopy and X-ray diffraction analysis revealed that vPOSS existed as crystalline aggregates, whereas ePOSS was more uniformly dispersed in the composites. The storage modulus and complex viscosity slightly decreased after the addition of vPOSS, but significantly increased after the addition of ePOSS, indicating the higher melt elasicity and broader processing window of the PLA/PBSA after the addition of ePOSS. The chloroform solutions of PLA/PBSA/ePOSS composites were turbid in appearance, and the extracted POSS showed absorbant peaks assigned to the vibration of OH and CO groups in the Fourier transform infrared spectroscopy analysis, indicating the reactions between ePOSS and the PLA/PBSA. Polarized optical microscopy analysis revealed that the two types of POSS could act as nucleating agents for PLA, and enhance its crystallization ability. Thermal gravimetric analysis showed that the addition of the two types of POSS increased the decomposition temperature and activation energy, consequently retarding the thermal degradation of PLA/PBSA. The retardation of degradation is more significant with the addition of ePOSS, for the reactions reduced the end groups of PLA/PBSA as well as the molecular chain mobility. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci 2009

The thermal stability of nylon 1010/polyhedral oligomeric silsesquioxane (POSS) composites prepared by melt blending was investigated with thermogravimetric analysis. The octavinyl POSS (vPOSS) and epoxycyclohexyl POSS (ePOSS) were used, and it was found that nylon/vPOSS composites have higher integral procedure decomposition temperature and char yield at 800°C than nylon/ePOSS composites. The Doyle–Ozawa (model-free) and Friedman (model-fitting) methods were used to characterize the nonisothermal decomposition kinetics of nylon 1010 and its composites. The activation energy (Ea), reaction order (n), and the natural logarithm of frequency factor of nylon 1010 were 267 kJ/mol, 1.0, and 47 min−1, respectively, in nitrogen. After the addition of POSS, the Ea of nylon 1010 considerably increased, whereas n had less change. The Ea steadily increased with increasing conversion and with increasing heating rate. The lifetime of nylon 1010 and its composites decreased with increasing temperature. At a given temperature, POSS significantly prolonged the lifetime of nylon 1010. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

The maleated poly(ethylene 1-octene) (POE-g-MAH)-toughened and glass fiber (GF)-reinforced nylon 1010 was prepared by melting extrusion. A good trade-off between stiffness and toughness was obtained by the combination of POE-g-MAH and GF. The essential work of fracture (EWF) model was used to characterize the fracture behavior of nylon/POE-g-MAH/GF composites. With increasing GF content, the energy consumed in outer plastic zone gradually decreased, and the work consumed in inner fracture process zone reached the maximum value at the GF content of 10 wt %. Morphology investigations showed that POE-g-MAH was uniformly dispersed in nylon/POE-g-MAH (80/20) blend, and the nylon around POE-g-MAH particles suffered a great plastic deformation in the impact test. For nylon/POE-g-MAH/GF composites, large plastic deformation occurred in the matrix around GF rather than around rubber particles. Dynamic mechanical analysis showed that GF significantly increased the storage and loss moduli and decreased value of tan δ, but had little effect on its position. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Heterometal alkoxide clusters of lanthanide and sodium, LnNa8[OC(CH3)3]10(OH) [where Ln = Nd (1) or Yb (2)], which were synthesized by the metathesis reaction of LnCl3 with NaOC(CH3)3 and NaOH in a 1 : 10 : 1 molar ratio in high yields and fully characterized including X-ray analysis for 2, were found to be highly active catalysts in the ring-opening polymerization of e-caprolactone and trimethylene carbonate and their copolymerization. All of the polymers obtained showed a unimodal molecular weight distribution, indicating that 1 and 2 could really be used as single-component catalysts. The dependence of catalytic activity on the lanthanide metals was observed: Yb < Nd. A coordination–insertion mechanism for the ring-opening polymerization is proposed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

The thermal degradation behavior of styrene-butadiene-styrene triblock copolymer (SBS) and SBS/multiwalled carbon nanotubes (MWCNTs) composites prepared by solution processing and melt mixing, respectively, was investigated using nonisothermal thermogravimetric analysis (TGA). The kinetic parameters of the activation energy (Ea) for degradation, preexponential factor A, and the reaction order (n) were evaluated by the Flynn-Wall-Ozawa, Kissinger, and Coats-Redfern methods, respectively. Ea increased and n decreased after the incorporation of 3 wt % of MWCNTs into the SBS. The Ea of SBS/MWCNTs composite prepared by melt mixing was higher than that by solution processing, which was attributed to the good dispersion of MWCNTs in SBS and the interactions between MWCNTs and SBS. The gases evolved during thermal degradation at a nitrogen atmosphere were studied by Fourier transform infrared spectroscopy (FTIR) coupled with the TGA. Aliphatic and aromatic CH peaks appeared simultaneously in FTIR spectra, indicating the thermal degradation of SBS proceeds by a random chain scission process. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Bis(3-triethoxysilylpropyl) tetrasulfide (TESPT) was used to improve the interfacial adhesion between cotton fiber and natural rubber (NR). The crosslink density, interfacial adhesion, mechanical properties, dynamic mechanical properties, and morphology of NR/cotton fiber composites were investigated. The composites with TESPT had higher crosslink density, better mechanical properties, higher initial modulus, and higher yield strength than the composites without TESPT because of the difference in interfacial adhesion. The results of an interfacial adhesion evaluation, the high storage modulus and low damping values of the composites with TESPT, and the coarse surfaces of the pullout fibers implied the enhancement of interfacial adhesion. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Polypropylene (PP)/octavinyl polyhedral oligomeric silsesquioxane (OvPOSS) composites were prepared by physical blending or reactive blending methods. The comparison of the PP/OvPOSS composites prepared by these two methods was investigated by mechanical tests, thermogravimetric analysis, and cone calorimeter. The graft ratio of OvPOSS to PP chain increased with increasing OvPOSS and dicumyl peroxide content for the reactive blending composites. The reactive blending composites had better mechanical properties, thermal stability than physical blending composites. The peak of the heat release rate and mass loss rate of PP/OvPOSS had also decreased, indicating better flame retardancy of PP/OvPOSS composites. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

The intercalation process and microstructural development of polybutadiene rubber (BR)/clay nanocomposites cured with sulfur were systematically investigated with respect to the organic modifier (primary and quaternary ammonium compounds) of the clay. X-ray diffraction spectra were recorded at various stages of processing to obtain information about the intercalation process. The rubber–filler interactions was examined on the basis of the surface free energy, stress-softening effect, and crystallization behavior. A well-ordered intercalated structure was obtained in the primary ammonium modified clay (POMMT) and quaternary ammonium modified clay (QOMMT) filled with BR composite. The BR/Q-OMMT composites showed higher mechanical properties and higher hysteresis under tension and lower crystallization abilities than the BR/P-OMMT composites. The results also show that higher interfacial interactions existed between QOMMT and BR than between P-OMMT and BR.

The rheological behavior of polypropylene/novolac blends was investigated with special reference to the effects of the blend ratio, compatibilization, and dynamic cure. The polypropylene and all the polypropylene/novolac blends presented evidence of shear-thinning behavior. The novolac, compatibilizer, and dynamic cure had dramatic effects on the rheological behavior of the polypropylene. Various rheological plots, including plots of the viscosity, storage modulus, loss modulus, and loss angle, Han plots, and Cole–Cole plots, were used to analyze the polypropylene/novolac blends. The results showed that the compatibilization together with the dynamic cure could increase the viscosity and modulus because of the formation of a grafting polymer between the maleic anhydride grafted polypropylene and the curing novolac resin. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007

Epoxycyclohexyl polyhedral oligomeric silsesquioxane (epoxy–POSS) was used to prepare a chain-extended poly(butylene terephthalate) (PBT) with a twin-screw extruder. The effect of epoxy–POSS on the melt flow index, mechanical properties, rheological behavior, and thermal properties of chain-extended PBT was investigated. PBT had an intrinsic viscosity of 1.1 dL/g and a carboxy1 content of 21.6 equiv/106 g, but the PBT chain-extended with 2 wt % epoxy–POSS had an intrinsic viscosity of 1.7 dL/g and a carboxy1 content lower than 7 equiv/106 g. After the addition of epoxy–POSS, the melt flow index of PBT dramatically decreased, the elongation at break increased greatly, the tensile strength increased slightly, and the thermal stability was also improved. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Ethylene–propylene–diene terpolymer foam was prepared by two different processing routes. The microstructure and mechanical properties of the foams with wide relative density ranging from 0.11 to 0.62 have been studied via scanning electron microscopy and mechanical testing, respectively. Scanning electron microscopy shows that the foam with lower relative density has a unique bimodal cell size structure, which the larger cells inlay among the smaller cells, while the foam articles with higher relative density have thicker cell walls with few small cells. The compressive stress–strain curves show that the foam articles with lower relative density have three regimes: linear elastic, a wide slightly rising plateau, and densification, while the foam articles with higher relative density have only two regimes: the longer linear elastic and densification. The relative modulus increases with the increase in the relative density. The contribution of the gas trapped in the cell to the modulus could be neglected. The energy absorbed per unit volume is relationship with the permitted stress and the relative density. The efficiency and the ideality parameter were evaluated from the compressive stress–strain plots. The parameters were plotted against stress to obtain maximum efficiency and the maximum ideality region, which can be used for optimizing the choice for practical applications in cushioning and packaging. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007

A polycarbonate (PC)/ poly (styrene-co-acrylonitrile) (SAN) alloy modified with styrene-ethylene-butylene-styrene (SEBS) block copolymer was prepared and the influence of SEBS content, PC content, and types of modifier on Izod notched impact strength, tensile strength, flexural strength, and Vicat softening temperature was studied. The results showed that the addition of SEBS could obviously increase the Izod notched impact strength and the elongation at break and decrease the tensile and flexural strength and Vicat softening temperature. PC/SAN alloy modified with SEBS had better mechanical properties than the PC/SAN alloy modified with ABS. DSC analysis and SEM photographs revealed that the SEBS was not only distributed in the SAN phase but also distributed in PC phase in a PC/SAN/SEBS alloy while the ABS was mainly distributed in SAN phase in a PC/SAN/ABS alloy. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007

In this article, the dynamic vulcanization process was applied to polypropylene (PP)/Novolac blends compatibilized with maleic anhydride-grafted PP (MAH-g-PP). The influences of dynamic cure, content of MAH-g-PP, Novolac, and curing agent on mechanical properties of the PP/Novolac blends were investigated. The results showed that the dynamically cured PP/MAH-g-PP/Novolac blend had the best mechanical properties among all PP/Novolac blends. The dynamic cure of Novolac improved the modulus and stiffness of the PP/Novolac blends. The addition of MAH-g-PP into dynamically cured PP/Novolac blend further enhanced the mechanical properties. With increasing Novolac content, tensile strength, flexural modulus, and flexural strength increased significantly, while the elongation at break dramatically deceased. Those blends with hexamethylenetetramine (HMTA) as a curing agent had good mechanical properties at HMTA content of 10 wt %. Scanning electron microscopy (SEM) analysis showed that dynamically cured PP/MAH-g-PP/Novolac blends had finer domains than the PP/MAH-g-PP/Novolac blends. Thermogravimetric analysis (TGA) results indicated that the incorporation of Novolac into PP could improve the thermal stability of PP. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007

Wollastonite reinforced polypropylene (PP/CaSiO3) composites were prepared by melt extrusion. A silane coupling agent and a maleic anhydride grafted PP (PP-g-MA) were used to increase the interfacial adhesion between the filler and the matrix. The increased adhesion observed by scanning electron microscopy (SEM) resulted in improved mechanical properties. A model was applied to describe the relationship between the interfacial adhesion and tensile properties of PP/CaSiO3 composites. There is stronger interfacial adhesion between silane-treated CaSiO3 and polymer matrix containing PP-g-MA as a modifier. Results of dynamic mechanical thermal analysis (DMTA) showed that stronger interfacial adhesion led to higher storage modulus. The influence of CaSiO3 particles on the crystallization of PP was studied by using differential scanning calorimetry (DSC). The introduction of CaSiO3 particles does not affect the crystallization temperature and crystallinity of PP matrix significantly.

Peroxide curing of brominated butyl rubber (BIIR) is an attractive topic, but the degradation of BIIR during the curing is a drawback needed to be overcome. Coagent assisted peroxide curing system is an attractive and effective choice in order to increase the crosslink density of rubbers. 1,2-polybutadiene (1,2-PB) is used as a crosslinking coagent for the curing of BIIR by dicumyl peroxide (DCP), and the effect of 1,2-PB on the curing characteristics, crosslink density, and mechanical properties is investigated. The addition of 1,2-PB affects the curing characteristics of BIIR compound and significantly increases the crosslink density of BIIR vulcanizates. With increasing 1,2-PB content, the tensile strength and stresses at a given extension of BIIR vulcanizates increase, but the elongation at break decreases. A stress-softening effect of the carbon black filled BIIR vulcanizates is observed and becomes more pronounced with increasing 1,2-PB content. The addition of 1,2-PB increases the stress relaxation index of BIIR. GPC and 13C-NMR results indicate 1,2-PB participates in the crosslinking reaction, and the existence of 1,2-PB component in the insoluble fraction of BIIR/1,2-PB vulcanizates is confirmed by solid-state 13C-NMR. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43280.