Structure and mechanical properties of nanodispersed fibrous silicate‐reinforced ethylene–propylene–diene monomer nanocomposites

In this study, ethylene–propylene–diene monomer (EPDM)/fibrillar silicate (FS) nanocomposites were successfully prepared by mechanically blending EPDM with FS, which was modified by silane coupling agent KH570 containing methacryloxy group. The effects of silane content and modified FS on the dispersion of FS and mechanical properties of the composites were investigated. The impact of water in FS on mechanical properties of the composites was also evaluated. The results showed that modified FS could be dissociated into nanofibers dispersing evenly in the EPDM matrix by increasing substantially the loading of silane through the mechanical blending. The optimum loading level of silane coupling agent was up to 24 phr/100 phr FS. Silane KH570 could improve the dispersion of FS and strengthen nanofibers–rubber interfacial adhesion even at the loading of as high as 50 phr FS, making FS to exhibit excellent reinforcement to EPDM. Too much FS could not be completely dissociated into nanofibers, slowing down further improvement. The EPDM/FS composites exhibited the similar stress–strain behavior and obvious mechanical anisotropy with short microfiber‐reinforced rubber composites. With the increase in silane coupling agent and modified FS, the number of nanofibers increased because of the exfoliation of FS microparticles; thus, the mechanical behaviors would become more obvious. It was suggested that the free water in FS should be removed before mechanically blending EPDM with FS because it obviously affected the tensile properties of the composites. Regardless of whether FS was dried or modified, the EPDM/FS composites changed little in tensile strength after soaked in hot water. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Mechanical properties and multiscale characterization of nanofiber–alumina/epoxy nanocomposites

In contrast to the bulk of published nanocomposite studies, in this study we investigated the mechanical properties of alumina/epoxy nanocomposites manufactured with nanofillers having a fiber or whisker morphology. The article describes how ultrasonic dispersion and in situ polymerization were used to incorporate these 2–4 nm diameter fibers (with aspect ratios of 25–50) into a two‐part epoxy resin (Epon 826/Epicure 9551). The use of untreated and surface‐modified nanoparticles is contrasted, and improvements in both the tensile strength and modulus were observed at low filler loadings. Microstructural characterization of the nanocomposites via multiscale digital image analysis was used to interpret the mechanical properties and was found to be useful for direct comparison with other nanocomposites. In addition, superior performance was demonstrated through comparisons with numerous nanocomposites with nanoparticle reinforcements ranging from carbon nanofibers to spherical alumina particles. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Morphology and mechanical properties of heterophasic PP–EP/EVA/organoclay nanocomposites

The effect of vinyl acetat (VA) on the morphological, thermal stability, and mechanical properties of heterophasic polypropylene–(ethylene‐propylene) copolymer (PP–EP)/poly(ethylene vinyl acetate) (EVA)/organoclay nanocomposites was studied. Tailored organoclay C20A was selected to enhance the exfoliation of the clay platelets. Depending on the VA content, there were two morphological organoclay populations in the systems. Both populations were directly observed by scanning transmission electron microscopy and measured by wide‐angle X‐ray diffraction and small‐angle X‐ray scattering. The content of VA in EVA originated spherical and elongated morphologies in the resultant nanocomposites. High‐VA content led to a better intercalation of the organoclay platelets. Measurement of thermal properties suggested that higher VA decreases thermal stability in samples both with and without organoclay, although nanocomposites had higher thermal stability than samples without clay. The storage modulus increased both with nanoclay and VA content. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Mechanical,thermal, and hydrophobic properties of silica aerogel–epoxy composites

Epoxy composites were prepared with different contents of hydrophobic silica aerogel particles to investigate their mechanical, thermal, and hydrophobic properties. The composites, particularly the one containing 1 wt % silica aerogel, showed remarkable toughness and yielding behaviors compared to neat epoxy, with its brittle behavior. As the content of silica aerogel increased, the thermal properties of the composites (e.g., thermal conductivity and thermal stability) improved. This was due to the very low thermal conductivity and high thermal stability of the silica aerogel particles. Moreover, the use of the hydrophobic silica aerogel led to the development of composites with hydrophobic properties. To examine the hydrophobicity more deeply, a series of water‐uptake tests were performed, and the results show that the composite with 3 wt % silica aerogel absorbed 50% less water than the neat epoxy. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45706.     

Effect of resin modifiers on the structural properties of epoxy resins

Thermomechanical, mechanical and fracture mechanical properties of modified epoxy resins with two different modifiers are investigated. Carboxyl‐terminated butadiene‐acrylonitrile (CTBN) is used as toughening agent and hexanediole diglycidyl ether (HDDGE) as reactive diluent. Both modifiers are admixed in contents from 0 up to 100 phr (parts per hundred resin) and exhibit flexibilizing and toughening qualities. The glass transition temperature is strongly depressed by the admixed reactive diluent, whereas the tensile modulus exhibits greater dependency on the toughening agent contents. The tensile strength and strain at break values are higher for the formulations with diluent compared to resins with toughening agent. Up to a content of 45 phr both modified systems exhibit comparable fracture toughness values. Only the toughened systems comprise increasing values for modifier amounts higher than 45 phr. For the formulation with both modifiers (toughening agent and diluent) a significantly higher toughness but a reduced glass transition temperature was obtained. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45348.     

Processing–structure–properties relationships of mechanically and thermally enhanced smectite/epoxy nanocomposites

Mechanically reinforced and thermally enhanced smectite/epoxy nanocomposites were synthesized using “direct” (without solvent) and “solvent” processing techniques. The molecular dispersion of smectite clay in the epoxy resin was investigated for its role in the rheology, structure formation, and properties of nanocomposites. The effects of three types of organic modifiers on the dispersion structure were compared. The use of solvent during processing assists in the enhancement of clay exfoliation. Rheology was used as a method to compare the degree of clay delamination in the resin matrix, as well as to estimate the suspension structure. The critical volume fraction (Φ*) and maximal packaging of smectites were determined and used for prediction of the viscosity. The qualitative changes in the nanostructure of suspensions above Φ*, due to flocculation of exfoliated clay layers, were compared with the alteration of the properties of nanocomposites, related to the structure formation and morphology. The curing kinetics were found to depend on both the organic modifier and solvent, but the extent of curing was roughly equivalent for the pure epoxy resin and the nanocomposites. The structure of the nanocomposites, either intercalated or exfoliated, produced by the direct processing technique was controlled by the organic modifier. By using solvent processing, the effect of the solvent dominates that of the organic modifier, presumably leading to exfoliated nanocomposites. The mechanical and thermal properties are strongly enhanced above the Φ* of smectites, and they are significantly dependent on the type of nanocomposite structure and the use of solvent. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2499–2510, 2005     

Simultaneously enhanced impact strength and dielectric properties of an epoxy resin modified with EHTPB liquid rubber

To simultaneously improve the impact strength and dielectric properties of cured epoxy (EP), herein we explore liquid rubber toughened EP based on a nonpolar epoxidized hydroxyl-terminated polybutadiene (EHTPB), where the rubber is covalently bonded to the EP. Fourier transform infrared and nuclear magnetic resonance proved the chemical reaction between EHTPB and EP, which makes the immiscible EHTPB-EP blend change to compatible one. The results indicate that both the impact strength and dielectric properties can be visibly enhanced with the addition of EHTPB and the maximum values are obtained at 10 phr of EHTPB loading. The improved mechanical toughness can be ascribed to the extensive shear yielding induced by the uniformly dispersed EHTPB domains and the enhanced interfacial compatibility between the two components. Moreover, the enhanced electrical resistivity and dielectric breakdown strength as well as the reduced dielectric constant and loss for the EHTPB-EP can be attributed to the combination of the excellent insulating properties of HTPB and dielectrically favorable interfaces. Therefore, the EHTPB-EP with a concurrent improvement in impact strength and dielectric properties can be used as promising insulating materials for high-frequency microelectronics and high-voltage electrical equipment.     

Morphology and thermal/mechanical properties of alkyl‐imidazolium‐treated rectorite/epoxy nanocomposites

A novel organic rectorite (OREC) was prepared by treating the natural sodium‐rectorite (Na‐REC) with ionic liquid 1‐hexadecyl‐3‐methylimidazolium bromide ([C₁₆mim]Br). X‐ray diffraction (XRD) analysis showed that the interlayer spacing of the OREC was expanded from 2.23nm to 3.14nm. Furthermore, two types of OREC/epoxy nanocomposites were prepared by using epoxy resin (EP) as matrix, 2‐ethyl‐4‐methylimidazole (2‐E‐4‐MI) and tung oil anhydride (TOA) as curing agents, respectively. XRD and transmission electron microscope (TEM) analysis showed that the intercalated nanocomposite was obtained with addition of the curing agent 2‐E‐4‐MI, and the exfoliated nanocomposite was obtained with addition of the curing agent TOA when the OREC content was less than 2 wt %. For the exfoliated nanocomposite, the mechanical and thermal property tests indicated that it had the highest improvement when OREC content was 2 wt% in EP. Compared to pure EP, 60.3% improvement in tensile strength, 26.7% improvement in bending strength, 34% improvement in bending modulus, 14°C improvement in thermal decomposition temperature (T_d) and 5.7°C improvement in glass transition temperature (T_g) were achieved. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Effects of spherical silica on the properties of an epoxy resin system

The spherical silica powders were prepared by using an oxygen–acetylene flame method. After spheroidization, a scanning electron microscope investigation revealed that the spheroidization efficiency of the powder was nearly 100%, XRD patterns indicated that the raw crystal silica became amorphous silica. In this study, composites of spherical silica and an epoxy resin were prepared with a homogenizer, followed by a stepwise thermal curing process. The thermal stability and thermal degradation behavior of the composites were studied by a thermogravimetric analyzer. Meanwhile, the effects of spherical silica powder on dynamic mechanical, coefficient of thermal expansion, and mechanical properties of epoxy/silica composites were also investigated. The initial decomposition temperature and mechanical properties increased significantly after adding the spherical silica into the composite. The maximum properties of thermal stability and mechanical properties were observed when spherical silica accounted for 30% of the system. The thermal expansion had been significantly reduced by the addition of silica. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Structure and properties of polyurethane–silica nanocomposites

Nanocomposites with different concentrations of nanofiller were prepared by adding nanosilica filler to the single‐phase polyurethane matrix. A control series was prepared with the same concentrations of micron‐size silica. The nanosilica filler was amorphous, giving composites with the polyurethane that were transparent at all concentrations. The nanocomposites displayed higher strength and elongation at break but lower density, modulus, and hardness than the corresponding micron‐size silica‐filled polyurethanes. Although the nanosilica showed a stronger interaction with the matrix, there were no dramatic differences in the dielectric behavior between the two series of composites. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 133–151, 2000     

Enhanced oil resistance and mechanical properties of nitrile butadiene rubber/lignin composites modified by epoxy resin

This is probably the first report on developing nitrile butadiene rubber (NBR) composites with enhanced performance s via lignin bridged epoxy resin in the rubber matrix. NBR/lignin masterbatch has been prepared through latex‐compounding method, and then epoxy resin (F51) was added in the NBR/lignin compounds by the melt compounding method. Lignin‐epoxy resin networks were synthesized in situ during the curing process of rubber compounds through epoxide?hydroxyl reactions. Compared with lignin filler, lignin‐F51 networks showed an improved oil resistance ability and led to increased mechanical properties, crosslinking density, and thermal stability of the rubber composites. This method provides a new insight into the fabrication of novel interpenetrating polymer networks in rubber composites and enlarges the potential applications of lignin in high performance rubber composites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42922.     

Reaction‐induced phase separation and resulting thermomechanical and surface properties of epoxy resin/poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) blends cured with 4,4′‐diaminodiphenylsulfone

We investigated the phase separation, cure kinetics and thermomechanical properties of diglycidyl ether of bisphenol‐A/4,4′‐diaminodiphenylsulfone/poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) (PEO–PPO–PEO) triblock copolymer (TBCP) blends. Fourier transform infrared spectroscopy, differential scanning calorimetry, and atomic force microscopy revealed that the blends exhibited heterogeneous phase morphology in which the TBCP formed dispersed domains in epoxy matrix, due to reaction induced phase separation. A fraction of phase‐separated PEO phase underwent partial crystallization whereas another fraction formed interphases between the dispersed domains and epoxy matrix. Moreover, the dispersed PEO chains improved the compatibility and interfacial adhesion between the matrix and domains and, consequently, significantly improved the mechanical properties of epoxy resin. Furthermore, the thermal degradation studies and contact angle measurements disclosed that the dispersed domains were well protected by the epoxy matrix. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44406.     

Morphology and mechanical and viscoelastic properties of rubbery epoxy/organoclay montmorillonite nanocomposites

The morphology and mechanical and viscoelastic properties of rubbery epoxy/organoclay montmorillonite (MMT) nanocomposites were investigated with wide‐angle X‐ray scattering (WAXS), transmission electron microscopy (TEM), tensile testing, and dynamic mechanical thermal analysis. An ultrasonicator was used to apply external shearing forces to disperse the silicate clay layers in the epoxy matrix. The first step of the nanocomposite preparation consisted of swelling MMT in a curing agent, that is, an aliphatic diamine based on a polyoxypropylene backbone with a low viscosity for better diffusion into the intragalleries. Then, the epoxy prepolymer was added to the mixture. Better dispersion and intercalation of the nanoclay in the matrix were expected. The organic modification of MMT with octadecylammonium ions led to an increase in the initial d‐spacing (the [d₀₀₁] peak) from 14.4 to 28.5 Å, as determined by WAXS; this indicated the occurrence of an intercalation. The addition of 5 phr MMTC18 (MMT after the modification) to the epoxy matrix resulted in a finer dispersion, as evidenced by the disappearance of the diffraction peak in the WAXS pattern and TEM images. The mechanical and viscoelastic properties were improved for both MMT and MMTC18 nanocomposites, but they were more pronounced for the modified ones. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 103: 3547–3552, 2007     

Investigation of nanostructure and properties of aromatic–aliphatic polyamide‐based nanocomposites with clay additives

Aromatic–aliphatic polyamide/clay nanocomposites were produced using solution intercalation technique. Surface modification of the clay was performed with ammonium salt of aromatic diamine and the polyamide chains were produced by condensation of 4‐aminophenyl sulfone with sebacoyl chloride (SCC) in dimethyl acetamide. Carbonyl chloride endcapped polymer chains were prepared by adding extra SCC near the end of polymerization reaction. The nanocomposites were investigated for organoclay dispersion, water absorption, mechanical, and thermal properties. Formation of delaminated and intercalated nanostructures was confirmed by X‐ray diffraction and TEM studies. Tensile strength and modulus improved for nanocomposites with optimum organoclay content (8 wt %). Thermal stability and glass transition temperatures of nanocomposites increased relative to pristine polyamide with augmenting organoclay content. The amount of water uptake for these materials decreased as compared with the neat polyamide. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation and properties of nylon 6/carboxylic silica nanocomposites via in situ polymerization

Nylon 6/carboxylic acid‐functionalized silica nanoparticles (SiO₂‐COOH) nanocomposites were prepared by in situ polymerization of caprolactam in the presence of SiO₂‐COOH. The aim of this work was to study the effect of carboxylic silica on the properties of the nylon 6 through the interfacial interactions between the SiO₂‐COOH nanoparticles and the nylon 6 matrix. For comparison, pure nylon 6, nylon 6/SiO₂ (unmodified) and nylon 6/amino‐functionalized SiO₂ (SiO₂‐NH₂) were also prepared via the same method. Fourier transform infrared spectrometer (FTIR) spectroscopy was used to evaluate the structure of SiO₂‐COOH and nylon 6/SiO₂‐COOH. The results from thermal gravimetric analysis (TGA) indicated that decomposition temperatures of nylon 6/SiO₂‐COOH nanocomposites at the 5 wt % of the total weight loss were higher than the pure nylon 6. Differential scanning calorimeter (DSC) studies showed that the melting point (T_m) and degree of crystallinity (X_c) of nylon 6/SiO₂‐COOH were lower than the pure nylon 6. Mechanical properties results of the nanocomposites showed that nylon 6 with incorporation of SiO₂‐COOH had better mechanical properties than that of pure nylon 6, nylon 6/SiO₂, and nylon 6/SiO₂‐NH₂. The morphology of SiO₂, SiO₂‐NH₂, and SiO₂‐COOH nanoparticles in nylon 6 matrix was observed using SEM measurements. The results revealed that the dispersion of SiO₂‐COOH nanoparticles in nylon 6 matrix was better than SiO₂ and SiO₂‐NH₂ nanoparticles. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Flame retardancy and mechanical properties of ferrum ammonium phosphate–halloysite/epoxy polymer nanocomposites

To recycle the nitrogen (N) and phosphorus (P) from wastewater, ferrum ammonium phosphate (FAP)–halloysite nanotubes (HNTs) were synthesized with simulated wastewater containing N, P, and Fe pollutants as raw materials. The adsorption–chemical precipitation in situ method was used to synthesize the target products, and the optimal conditions for the synthesis of the FAP–HNTs were obtained. Fourier transform Infrared (FTIR) spectroscopy, energy‐dispersive spectroscopy (EDS), scanning electron microscopy, transmission electron microscopy, and thermogravimetric analysis were conducted to characterize the samples. The FAP particle size was 20–30 nm in the FAP–HNTs. The FTIR spectra demonstrated that a small amount of water in the FAP–HNTs promoted the curing reaction. The FAP–HNTs and Exolit OP 1230 (OP) were introduced into epoxy (EP) to prepare the polymer nanocomposites. The heat release rate (HRR) and flammability of the EP composites were tested by microscale combustion calorimetry and UL‐94 instruments. The mechanical properties of the EP composites also were tested by a tension testing system. The results indicate that the flame retardancy and mechanical properties of the EP composites were improved by FAP–HNT. The addition of FAP–HNT and OP gave rise to an evident reduction of HRR and a prolonged burning time for the EP. EP/FAP–HNT/OP (20) (where 20 is the loading weight percentage) passed the UL 94 V‐0 rating. The analysis of the char revealed the synergy of the FAP–HNTs and OP in reducing the flammability of the polymers. We concluded that these polymers show potential for applications in wastewater treatment and N/P recycling. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41681.     

Preparation and properties of poly(dimethyl siloxane)–colloidal silica/functionalized colloidal silica nanocomposites

Aqueous spherical colloidal silica (CS) particles with a diameter of 15 ± 5 nm were modified with three different types of monofunctional silane coupling agents to prepare functionalized colloidal silica (FCS) particles. The effects of the surface chemistry of the FCS were studied as a function of the CS/FCS loading in the poly(dimethyl siloxane) (PDMS) polymer. The prepared PDMS–CS/FCS composites were investigated for their physical properties both in the cured and uncured states. The extent of filler–filler and filler–polymer interactions was found to vary with the type of functionalizing agent used to treat the surface of the CS. The filler–filler interaction appeared to be predominant in the PDMS–CS composites, and improved filler–polymer interaction was indicated in the case of the PDMS–FCS composites. The composites containing CS treated with methyltrimethoxysilane exhibited relatively better optical and mechanical properties compared to the other PDMS–FCS composites. This study highlighted the importance of judiciously choosing functionalizing agents to achieve PDMS–FCS composites with predetermined optical and mechanical properties. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Mechanical and morphological properties of organic–inorganic,hybrid, clay‐filled,and cyanate ester/siloxane toughened epoxy nanocomposites

Organic–inorganic hybrids involving cyanate ester and hydroxyl‐terminated polydimethylsiloxane (HTPDMS) modified diglycidyl ether of bisphenol A (DGEBA; epoxy resin) filled with organomodified clay [montmorillonite (MMT)] nanocomposites were prepared via in situ polymerization and compared with unfilled‐clay macrocomposites. The epoxy‐organomodified MMT clay nanocomposites were prepared by the homogeneous dispersion of various percentages (1–5%), and the resulting homogeneous epoxy/clay hybrids were modified with 10% HTPDMS and γ‐aminopropyltriethoxysilane as a coupling agent in the presence of a tin catalyst. The siliconized epoxy/clay prepolymer was further modified separately with 10% of three different types of cyanate esters, namely, 4,4′‐dicyanato‐2,2′‐diphenylpropane, 1,1′‐bis(3‐methyl‐4‐cyanatophenyl) cyclohexane, and 1,3‐dicyanato benzene, and cured with diaminodiphenylmethane as a curing agent. The reactions during the curing process between the epoxy, siloxane, and cyanate were confirmed by Fourier transform infrared analysis. The results of dynamic mechanical analysis showed that the glass‐transition temperatures of the clay‐filled hybrid epoxy systems were lower than that of neat epoxy. The data obtained from mechanical studies implied that there was a significant improvement in the strength and modulus by the nanoscale reinforcement of organomodified MMT clay with the matrix resin. The morphologies of the siloxane‐containing, hybrid epoxy/clay systems showed heterogeneous character due to the partial incompatibility of HTPDMS. The exfoliation of the organoclay was ascertained from X‐ray diffraction patterns. The increase in the percentage of organomodified MMT clay up to 5 wt % led to a significant improvement in the mechanical properties and an insignificant decrease in the glass‐transition temperature versus the unfilled‐clay systems. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Temperature and frequency‐dependent creep and recovery studies on PVDF‐HFP/organo‐modified layered double hydroxides nanocomposites

A series of poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP) loaded with various contents of layered double hydroxides (LDHs) nanoparticles were prepared via a melt mixing method. Detailed investigations on LDH dispersion state in the polymeric matrix conducted by TEM revealed intercalated/exfoliated, and agglomerated structures at low (1 wt %) and high (>3 wt %) loadings of LDH contents, respectively. Wide angle X‐ray scattering and DSC results showed that incorporation of LDH into PVDF‐HFP matrix reduced its overall crystallinity and helped to form polar crystallites, while the crystal size at 020 crystallographic directions was found to be most affected by presence and dispersion state of LDH in the matrix. TGA results showed LDH improved thermal stability of matrix however, unlike many other nanomaterials it significantly reduced the residual mass which highlights catalytic role of LDH in degradation of residual carbon char. Detailed analysis on creep and recovery data over wide range of selected temperatures revealed that the creep compliance of nanocomposites are basically controlled by crystallinity and presence of LDH at low and high temperatures, respectively. Based on obtained storage modulus and creep compliance master curves it was also found that the influence of LDH on decreasing the creep compliance and improving viscoelastic properties of PVDF‐HFP over long time period and over high frequency ranges becomes more pronounced. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46352.     

Reprocessing effects on polypropylene/silica nanocomposites

A polypropylene matrix was melt compounded with a given amount (2 vol %) of both untreated (hydrophilic) and surface treated (hydrophobic) fumed silica nanoparticles with the aim to investigate the influence of the time under processing conditions on the microstructure and thermo‐mechanical properties of the resulting materials. Chain scission reactions induced by thermal processing caused a remarkable decrease of the melt viscosity, as revealed by the melt flow index values of both neat matrix and nanocomposites, but the degradative effect was significantly hindered by the presence of silica nanoparticles. It was observed that the size of nanofiller aggregates noticeably decreased as the compounding time increased, especially when hydrophobic silica nanofiller was considered. While the melting temperature seemed to be unaffected by the processing time, a remarkable embrittlement of the samples was observed for prolonged compounding times. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40242.