Influence of symmetry/asymmetry of the nanoparticles structure on the thermal stability of polyhedral oligomeric silsesquioxane/polystyrene nanocomposites

The thermal degradation of two polyhedral oligomeric silsesquioxane/polystyrene (POSS/PS) nanocomposites of formula R₈(SiO_1.5)₈ POSS/PS and R′₁R₇(SiO_1.5)₈ POSS/PS (where R′ = Phenyl and R = Cyclopentyl), at 5% of POSS concentration, was studied in both inert (flowing nitrogen) and oxidative (static air) atmospheres. Compounds were prepared by the polymerization of styrene in the presence of POSS. Degradations were carried out into a thermobalance, in the scanning mode, at various heating rates, and the obtained thermogravimetric (TG) curves were discussed and interpreted. The initial decomposition temperature (T_i), the temperature at 5% mass loss (T_5%), the glass transition temperature (T_g), and the activation energy (E_a) of degradation of nanocomposites were determined and compared with each other and with those of unfilled PS. The T_i, T_5%, and degradation E_a values of nanocomposites were higher than those of neat PS, thus indicating a better heat resistance and lower degradation rate, and then a better overall thermal stability. The use of POSS with a symmetric structure, in the synthesis of PS based nanocomposite, showed a decrease of T_g value not only in respect to asymmetric POSS/PS nanocomposite but also in respect to neat polymer, thus suggesting an influence of filler structure in the thermal properties of the materials. POLYM. COMPOS., 33:1903–1910, 2012. © 2012 Society of Plastics Engineers     

Microstructural characterization of short glass fiber and PAN based carbon fiber reinforced nylon 6 polymer composites

Microstructural characterization of nylon 6/short glass fiber (SGF) and nylon 6/polyacrolonitrile based carbon fibers (PAN‐CFs) of 10 to 40 wt% has been performed by positron lifetime technique (PLT). The positron lifetime parameters viz., o‐Ps lifetime (τ₃), o‐Ps intensity (I₃), and fractional free volume (F_v) of nylon 6/SGF and nylon 6/PAN‐CF composites are correlated with the mechanical properties viz., tensile strength and Young's modulus. The F_v shows negative deviation with the reinforcement of 10 to 40 wt% of PAN‐CF and show positive deviation in nylon 6/SGF from the linear additivity relation. The negative deviation in nylon 6/PAN‐CF composite suggests the induced molecular packing due to the chemical interaction between the polymeric chains of nylon 6 and PAN‐CF. The positive deviation in nylon 6/SGF composite indicates the formation of interface between the polymeric chains of nylon 6 and SGF. The increased crystallinity of nylon 6/SGF and nylon 6/PAN‐CF composites shows the improved mechanical properties of the composites. The hydrodynamic interaction parameter (h), which shows more negative values in nylon 6/SGF than nylon 6/PAN‐CF composites. However, the extent of chemical interaction in nylon 6/SGF is less compare to nylon 6/PAN‐CF composites. This is evident from Fourier transform infrared spectrometry studies. POLYM. ENG. SCI., 58:1428–1437, 2018. © 2017 Society of Plastics Engineers     

On-Line Rheological Measurements and Mechanical Properties of Acrylonitrile-Butadiene-styrene/Corn Starch Composite

In this work, rheological and mechanical properties of acrylonitrile–butadiene–styrene/corn starch composites (ABS/starch) were studied. The composites were prepared using a laboratory-scale, single-screw extruder. Rheological properties were determined using the single-screw extruder, apparent shear rate (γ _a ), apparent shear stress (τ _a ), apparent viscosity (η _a ), non-Newtonian index (n), and flow activation energy at a constant shear rate (E _γ) and constant shear stress (E _τ). Mechanical properties in terms of tensile tests were performed using Testometric M350-10KN, stress at break, strain at break, and Young's modulus were determined. Rheological results showed that the composites are pseudo plastic in behavior, and the apparent viscosity of the composites increases with increasing starch content above the additive rule, which indicates a partial compatibility in the composite. It was also found that the flow activation energy of the composite increases with increasing starch content. The mechanical results showed that the strain at break of the composite decreases sharply by the presence of starch, whereas the Young's modulus increases with increasing starch content.     

Effect of in situ surface‐modified nano‐SiO2 on the thermal and mechanical properties and crystallization behavior of nylon 1010

Nylon 1010 composites filled with two types of surface‐modified SiO₂ nanoparticles (RNS and DNS) were prepared by melt blending. The mechanical properties of the composites were evaluated. The influences of the surface‐modified nano‐SiO₂ on the thermal stability, crystallization behavior, and microstructure of nylon 1010 were investigated by thermogravimetric analysis, differential scanning calorimetry (DSC), X‐ray diffraction, and transmission electron microscopy. And the interfacial interactions between the fillers and polymer matrix were examined using a Fourier transformation infrared spectrometer. It was found that the addition of the surface‐modified nano‐SiO₂ had distinct influences on the thermal stability, mechanical properties, and crystallization behavior of nylon 1010. RNS and DNS as the fillers had different effects on the mechanical properties of nylon 1010. The composites filled with RNS at a mass fraction of 1–5% showed increased break elongation, Young's modulus, and impact strength but almost unchanged or even slightly lowered tensile strength than the unfilled matrix. The DNS‐filled nylon 1010 composites had obviously decreased tensile strength, whereas the incorporation of DNS also contributed to the increase in the Young's modulus of nylon 1010, but less effective than RNS. Moreover, the nylon 1010 composites had better thermal stability than the neat polymer matrix, and the composites filled with RNS were more thermally stable than those filled with DNS. The difference in the crystallinity of neat nylon 1010 and its composites filled with RNS and DNS was subtle, although the surface‐modified nano‐SiO₂ could induce or/and stabilize the γ‐crystalline formation of nylon 1010. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effect of octa(epoxycyclohexyl) POSS on thermal,rheology property,and foaming behavior of PLA composites

Foams of poly(lactic acid) (PLA)/octa(epoxycyclohexyl) polyhedral oligomeric silsesquioxanes (ePOSS) composite were prepared by melt‐mixing and solid‐state foaming methods. A systematic and accurate method was applied to evaluate the effects of epoxy‐based POSS on the structure of dispersion, thermal behavior, and rheological properties of PLA composites. The application of secondary electron–electron back‐scattered diffraction technique was used to observe the cellular micromorphology and micro‐phase dispersion in composite foams, simultaneously. The results indicated that secondary dispersion of POSS aggregates occurred in foaming process. The enhanced melt elasticity, dispersity of POSS, and crystallization morphology of PLA/POSS composite had a significant effect on the controlling foaming behavior. Thus, a homogeneous and finer cellular morphology of PLA/POSS composite foam with high expansion ratio was obtained with a proper content of POSS in the composites. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46399.     

Comparison of the toughening effects of different elastomers on nylon 1010

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 (d_n) 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 d_n, while the limited specific fracture energy increased with increasing d_n when d_n was below 1 μm and then sharply decreased with further increasing d_n. 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     

Octa(aminophenyl) polyhedral oligomeric silsesquioxane/boron‐containing phenol–formaldehyde resin nanocomposites: Synthesis,cured, and thermal properties

Octa(aminophenyl) polyhedral oligomeric silsesquioxane (OAP‐POSS) and boron‐containing phenol‐formaldehyde resin (BPFR) were synthesized, respectively. The BPFR nanocomposites with different OAP‐POSS content (wt%) were prepared, and their properties were characterized. The results show that the thermal degradation process of this nanocomposites can be divided into three stages, and they are all following the first order mechanism. The residual ratio and thermal degradation activation energy E_a of 9 wt% OAP‐POSS/BPFR nanocomposites are both better than others and the E_a increase gradually in three stages, which is 93.3, 134.0, and 181.9 kJ mol⁻¹, respectively. Its residual ratio at 900°C is 36.48%. The mechanical loss peak temperature T_p is 228°C for 12 wt% OAP‐POSSS/BPFR nanocomposites, which is higher 48°C than pure BPFR. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

Electrical and thermal properties of γ‐irradiated nitrile rubber/rice husk ash composites

The effects of both the rice husk ash (RHA) loading and fumed silica (FS) loading on the structure, thermal stability, and electrical properties of acrylonitrile–butadiene rubber (NBR) composites were studied. The filler loading were chosen to be 5 and 20 phr for RHA and 5 and 30 phr for silica. Also, the effect of the γ‐irradiation dose (25 kGy) on these parameters was investigated. The structure and thermal stability were studied with X‐ray diffraction and thermogravimetric analysis techniques. Furthermore, some electrical parameters, such as the direct‐current electrical conductivity (σ_dc), activation energy (E_a), dielectric constant (?′), and dielectric loss (?″), were determined. The incorporation of both RHA and FS resulted in improved thermal stability after γ irradiation at 25 kGy. The loading of FS on NBR was shown to decrease σ_dc, ?′, and ?″ and increase E_a. On the other hand, the loading of RHA showed the opposite trend. Finally, γ irradiation of NBR composites filled with both fillers decreased the values of σ_dc, ?′, and ?″ for all the samples, which followed the trend for the unirradiated composites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Thermal conductivity and thermal properties of POSS/polytriazole organic–inorganic hybrid material

To decrease the thermal conductivity of polytriazole‐based fiber reinforced composites, an organic–inorganic POSS/polytriazole hybrid resin was obtained. The influences of various proportions of POSS on thermal conductivity and the thermal properties of hybrid materials were emphatically investigated. The results show that POSS incorporation resulted in not only decreased thermal conductivity but also increased T_g and thermal decomposition temperature. The enhancement was ascribed to the nanoscale effect of POSS structure and the fact that the POSS framework has a high heat resistance property. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41967.     

Thermal properties of extruded injection‐molded poly(lactic acid) and milkweed composites: Degradation kinetics and enthalpic relaxation

To determine the degree of compatibility between poly(lactic acid) (PLA) and different biomaterials, PLA was compounded with milkweed fiber, a new crop oil seed. After oil extraction, milkweed remaining cake retained approximately 10% residual oil, 47% protein, and 10% moisture. The fiber (300 μm) was added at 85 : 15 and 70 : 30 PLA : Fiber and blended by extrusion (EX) followed by injection molding (IM). Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used for testing the composites. After melting in the DSC sealed pans, composites were cooled by immersion in liquid nitrogen and aged (stored) at room temperature for 0, 7, 15, and 30 days. After storage, samples were heated from room temperature to 180°C at 10°C/min. The pure PLA showed a glass transition (T_g) at 60.3°C and the corresponding ΔCp was 0.464 J/g/°C followed by crystallization and melting transitions. The enthalpic relaxation (ER) of neat PLA and composites steadily increased as a function of storage time. Although the presence of fiber had little effect on ER, IM reduced it. The percentage crystallinity of neat unprocessed PLA dropped by 95 and 80% for the EX and IM, respectively. The degradation activation energy (E_a) of neat PLA exhibited a significant drop in nitrogen environment, whereas increased in air, indicating PLA resistant to heat degradation in the presence of oxygen. Overall, IM appeared to decrease E_a of the composites, whereas milkweed significantly reduced E_a values in nitrogen environment. Enzymatic degradation of the composites revealed higher degradation rate for the EX samples versus IM, whereas 30% milkweed exhibited higher weight loss compared to the 15%. The degradation mechanism was observed by looking at the percent conversion as a function of E_a from the TGA data, where multisteps degradation occurred mostly in air. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Epoxy/POSS organic–inorganic hybrids: Viscoelastic,mechanical properties and micromorphologies

A series of epoxy resin (EP)/octa(aminpropyl)silsesquioxane (POSS‐NH₂) organic–inorganic hybrid composites (EP/POSS‐NH₂ 100/0, 95/5, 90/10, and 80/20 wt/wt) were prepared by melt casting and then curing. Viscoelastic and mechanical properties of these composites were studied by dynamic mechanical analysis and mechanical testing, respectively. Scanning electron microscopy was used to study of the micromorphologies of the composites and to elucidate the toughening mechanisms of POSS‐NH₂. POSS units incorporated into the epoxy network showed good compatibility with the resin matrix. Phase separation was not observed even at high POSS content (20 wt%). Incorporation of POSS macromer into the epoxy network after curing increased the glass transition temperature, slightly narrowed the temperature range widths of the glass transition, and lowered the intensities of their loss moduli peaks of the resultant composites. The glass transition temperature of EP/POSS‐NH₂ composites increased significantly with increasing POSS content at lower POSS content (<10 wt%), while increased slightly at higher POSS content. Both impact and flexural strengths of the hybrids reached their optimum values when 10 wt% content of POSS was introduced. POLYM. COMPOS., 28:175–179, 2007. © 2007 Society of Plastics Engineers.     

Effect of the filler size and content on the thermomechanical properties of particulate aluminum nitride filled epoxy composites

Polymer matrix composites based on brominated epoxy as the matrix and aluminum nitride (AlN) particles as the filler were prepared. The influences of the size, content, and size distribution of AlN on the thermomechanical properties, including the glass‐transition temperature (T_g), coefficient of thermal expansion (CTE), dynamic storage modulus (E′), dynamic loss modulus (E″), and loss factor (tan δ), of the composites were investigated by thermomechanical analysis and dynamic mechanical analysis. There was a total change trend for T_g; that is, T_g of the composites containing nano‐aluminum nitride (nano‐AlN; 50 nm) was lower than that of the micro‐aluminum nitride (micro‐AlN; 2.3 μm) filled composites, especially at high nano‐AlN contents. The T_g depression of the composites containing nano‐AlN was related to the aggregation of nano‐AlN and voids in the composites. On the other hand, the crosslink density of the epoxy matrix decreased for nano‐AlN‐filled composites, which also resulted in a T_g depression. The results also show that E′ and E″ increased, whereas tan δ and CTE of the composites decreased, with increasing the AlN content or increasing nano‐AlN fraction at the same AlN content. These results indicate that increasing the interfacial areas between AlN and the epoxy matrix effectively enhanced the dynamic modulus and decreased CTE. In addition, at a fixed AlN content of 10 wt %, a low E′ of pre‐T_g (before T_g temperature) and high T_g were observed at the smaller weight ratio of nano‐AlN when combinations of nano‐AlN plus micro‐AlN were used as the filler. This may have been related to the best packing efficiency at that weight ratio when the bimodal filler was used. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Study on thermal enhancement mechanism of POSS‐containing hybrid nanocomposites and relationship between thermal properties and their molecular structure

In this study, a series of poly(4‐acetoxystyrene) (PAS)‐octavinyl polyhedral oligomeric silsesquioxane (POSS) blends and the polystyrene (PS)‐octavinyl POSS blends were prepared by the solution‐blending method and characterized with Fourier transform infrared (FTIR), X‐ray diffraction (XRD), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA) techniques. The results show that the glass‐transition temperature (T_g) of the PAS‐POSS blends increases at a relatively low POSS content and then decreases at a relatively high POSS content. POSS can effectively improve the thermal stability of the PAS‐POSS blends at low POSS content, and T_g of PAS‐POSS blends decreases with the increase in POSS content at relatively high POSS content. However, the T_g of the PS‐POSS blends persistently decreases even at very low POSS content. T_g change mechanism was investigated in detail by XRD, TEM, and FTIR spectra. The influence mechanism of POSS content and dispersion in composites, and parent polymer structure on thermal properties of the blends was investigated in detail. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Curing and pyrolysis of cresol novolac epoxy resins containing [2‐(6‐oxido‐6H‐dibenz(c,e)(1,2)oxaphosphorin‐6‐yl)‐1,4‐naphthalenediol]

This study investigates the curing kinetics, thermal properties and decomposition kinetics of cresol novolac epoxy (CNE) with two curing agents, 2‐(6‐oxido‐6H dibenz(c,e)(1,2) oxaphosphorin‐6‐yl)‐1,4‐benzenediol (ODOPN), and phenol novolac (PN). In comparison with the conventional PN system, introducing ODOPN, a phosphorus‐containing bulky pendant group, into CNE increases T_g by 33°C, char yield from 30% to 38%, and LOI from 22 to 31. The DSC curing study reveals that the E_a of the CNE/ODOPN epoxy can be obtained by Kissinger's method. The resulting E_a values indicate that the catalytic effect of EMI is insignificant on CNE/ODOPN but is marked on CNE/PN, whose E_a was reduced from 131.5 to 75.6 KJ/mole. This result may be caused by the fact that the symmetric diol attached to the 1 and 4 positions of the naphthalene ring in ODOPN sets up a steadily resonating structure and inhibits the catalytic action. Further investigating the conversion ratio with curing temperature yielded experimental data that agreed closely with Kaiser's model. The orders of the autocatalyzed reaction, m, and the crosslinking reaction, n, are close to 0.5 and 1.0, respectively, independently of the scan rate. Finally, the TGA decomposition study by Ozawa's method demonstrates that the mean E_a declines with the phosphorus content, because the easy decomposition of the phosphorus compound in the initiation stage facilitates the formation of an insulating layer. However, results in this study further reveal an increasing tendency for E_a with decomposition conversion for an ODOPN/PN mixture with the ODOPN content of over 50%, probably because of the retardation of gas diffusion by the insulating layer of phosphorus compound.     

A study on the curing kinetics of epoxycyclohexyl polyhedral oligomeric silsesquioxanes and hydrogenated carboxylated nitrile rubber by dynamic differential scanning calorimetry

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 (E_a) 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 E_a 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     

Anionic nylon 6/TiO2 composite materials: Effects of TiO2 filler on the thermal and mechanical behavior of the composites

The nylon 6‐based composite materials containing untreated and surface‐treated TiO₂ particles with 3‐aminopropyltriethoxysilane (APTEOS), as coupling agent were prepared by in situ anionic polymerization of ε‐caprolactam in the presence TiO₂ as a filler using the rotational molding technique. The thermal behavior and mechanical properties of the neat nylon 6 and its composites were investigated using various techniques such as differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), a tensile and flexural test and impact strength. Experimental results revealed that both untreated and surface‐modified TiO₂ had distinct influence on the melting temperature (T_m), crystallization temperature (T_c), and degree of crystallinity (α_DSC), thermal stability, storage modulus (E′), and loss factor (tan δ), and mechanical properties of nylon 6 matrix. Dynamical mechanical analysis indicated that addition of TiO₂ particles into nylon 6 matrix increased both the storage modulus and the glass transition temperature. The corresponding values of nylon 6 composites with modified filler were higher than that of nylon 6 composite with untreated TiO₂ particles. Tensile and flexural characteristics of the nylon 6 composites were found to increase while the elongation at break and impact strength with increase in TiO₂ concentration relative to neat nylon 6. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

The influence of chain‐ends on the thermal and rheological properties of some 40/60 PES/PEES copolymers

Four random, differently ended (? Cl, ? NH₂, ? OH, and ? COO^?), polyethersulfone/polyetherethersulfone (PES/PEES) copolymers were studied to investigate the influence of chain ends on thermal and rheological behaviors. The number average molar mass (M_n ≈ 9500 g·mol^?1) and the PES/PEES ratio (40/60) of all copolymers investigated were checked by ¹H NMR spectra. Thermal degradations were carried out in the scanning mode and initial decomposition temperatures (T_i) and activation energy values of degradation (E_a) were obtained. Glass transition temperature (T_g) was determined by differential scanning calorimetry and complex viscosity (η*) by rheological measurements in isothermal heating conditions (T = 270°C). All parameters determined were largely affected by copolymer chain ends and decreased according to the same order, ? OH > ? NH₂ > ? Cl > ? COO^?. The results were discussed and interpreted. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

Chemical Bonding between Phenolic Resins and Polyhedral Oligomeric Silsesquioxanes (POSS) in Inorganic–Organic Hybrid Nanocomposites

Three classes of inorganic–organic hybrid phenolic resin/polyhedral oligomeric silsesquioxane (POSS) nanocomposites were synthesized. Multifunctional dichloromethylsilylethylheptaisobutyl-POSS (POSS-1), trisilanolheptaphenyl-POSS (POSS-2), and poly(phenylsilsesquioxane) uncured POSS (POSS-3) were employed. Nonfunctional POSS-4 (octaisobuty1-POSS) was blended into the uncured phenolic resin and cured under the same conditions used for the other three nanocomposite classes. Weight ratios of 99/1, 97/3, 95/5 and 90/10 were prepared for the POSS-1, 2 and 4 series and 99/1, 97/3 and 95/5 ratios for the POSS-3 nanocomposites. POSS-1 incorporation into this phenolic resin network increases T _g and broadens the tan peak (DMTA) range. T _g and E′ values at T>T _g both increase with higher POSS-1 content. In contrast, incorporating 5 wt% of POSS-2 into the phenolic resin network lowers T _g to 193 from 213°C for the neat phenolic resin. All values of E′ for POSS-2 composites were higher, than those of the phenolic control in both glassy and rubbery regions. The T _g values of the 1 and 10% POSS-2 systems were higher. Incorporating 10 wt% of POSS-1 or POSS-2 improved the heat distorsion temperature and moduli (E′=123 and 201 GPa at 265°C, respectively, versus 56 GPa for the pure phenolic resin). Increases in E′ for T>T _g and T<T _g were also observed for all POSS-3 nanocomposites. However, the E′ at T>T _g and the T _g values of the POSS-4 composites were lower than those of the control resin. Octaisobutyl POSS-4 cannot form chemical bonds to the resin and could be extracted from its composites with THF. POSS derivatives were not present in residues extracted by THF from the phenolic resins containing POSS-1, 2 or 3, because each of these derivatives were chemically bound within the phenolic resin. Subsequent heating cycles produce much larger increases in T _g and E′ values in the rubbery region for the POSS-1, 2 and 3 composites than for the neat phenolic resin or for the POSS-4 systems. An erratum to this article can be found at     

Polypropylene/natural rubber composites filled with recycled newspaper: Effect of chemical treatment using maleic anhydride‐grafted polypropylene and 3‐aminopropyltriethoxysilane

A study on effect of chemical treatment using maleic anhydride‐grafted polypropylene (MAPP) and 3‐aminopropyltiethoxysilane (3‐APE) was investigated. The performance of the MAPP and 3‐APE were investigated by means of torque development, mechanical properties, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy morphology, and water absorption. The results revealed that the use of MAPP or 3‐APE in the composites has increased the stabilization torque, tensile strength, Young's modulus, water absorption, and thermal stability of the PP/NR composites. The incorporation of MAPP in the composites shows higher stabilization torque, tensile strength, E_B, Young's modulus, and lower water uptake when compared with the use of 3‐APE in the PP/NR composites. TGA and DSC results indicated that primary and secondary peak of DTG curve, initial degradation temperature (T₀), degradation temperature (T_deg), melting temperature (T_m), heat of fusion of composites (ΔH_f(com)), crystallinity of composites (X_PP), and PP (X_PP) increased, while total weight loss and thermal degradation rate decreased for both treated composites. The MAPP‐treated RNP‐filled PP/NR composites were found to be more thermal resistance and more crystalline than 3‐APE‐treated filled PP/NR RNP composites. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

Mechanical properties,thermal stability,and thermal degradation kinetics of silicone rubber/ethylene-vinyl acetate copolymer/magnesium sulfate whisker composites compatibilized by ethylene-acrylic acid copolymer

Silicone rubber/ethylene-vinyl acetate copolymer/magnesium sulfate whisker composites containing ethylene-acrylic acid copolymer (MS/SR/EVM/EAA) as a compatibilizer were successfully prepared. Moreover, the magnesium sulfate whisker surface was modified with 3 wt% of silane coupling agent (KH570), resulting in composites including (unmodified magnesium sulfate whisker) uMS/SR/EVM, (modified magnesium sulfate whisker) mMS/SR/EVM, and mMS/SR/EVM/EAA were compared. The values of thermal decomposition activation energy (E_a) calculated by the two different methods (Kissinger and Friedman methods) show that the composites filled with 5 and 20 phr whiskers have lower values of activation energy (E_a) than the SR/EVM blend. The tensile strength of composites with a 5 phr modified whisker is 14.5 MPa, which is higher than that of the SR/EVM blend and uMS5/SR/EVM composite. The tear strength of the composite with 20 phr mMS is 51.6 kN m⁻¹, much higher than that of the composite with 20 phr uMS and SR/EVM blend. The mechanical properties were also investigated after thermal aging of the composites at 85°C for 48 h. The thermal conductivity of the composites with high filler loading was studied.