In‐situ reinforcement of PBT/ABS blends with liquid crystalline polymer

Ternary in‐situ poly(butylene terephthalate) (PBT)/poly(acrylonitrile‐butadienestyrene) (ABS)/liquid crystalline polymer(LCP) blends were prepared by injection molding. The LCP used was a versatile Vectra A950, and the matrix material was PBT/ABS 60/40 by weight. Maleic anhydride (MA) copolymer and solid epoxy resin (bisphenol type‐A) were used as compatibilizers for these blends. The tensile, dynamic mechanical, impact, morphology and thermal properties of the blends were studied. Tensile tests showed that the tensile stregth of PBT/ABS/LCP blend in the longitudinal direction increased markedly with increasing LCP content. However, it decreased sharply with increasing LCP content up to 5 wt%; thereafter it decreased slowly with increasing LCP content in the transverse direction. The modulus of this blend in the longitudinal direction appeared to increase considerably with increasing LCP content, whereas the incorporation of LCP into PBT/ABS blends had little effect on the modulus in the transverse direction. The impact tests revealed that the Izod impact strength of the blends in longitudinal direction decreased with increasing LCP content up to 10 wt%; thereafter it increased slowly with increasing LCP. Dynamic mechanical analyses (DMA) and thermogravimetric measurements showed that the heat resistance and heat stability of the blends tended to increase with increasing LCP content. SEM observation, DMA, and tensile measurement indicated that the additions of epoxy and MA copolymer to PBT/ABS matrix appeared to enhance the compatibility between PBT/ABS and LCP.     

Properties of ternary in situ polycarbonate/polybutylene terephthalate/liquid crystalline polymer composites

Ternary in situ polycarbonate (PC)/polybutylene terephthalate (PBT)/liquid crystalline polymer (LCP) composites were prepared by injection molding. The liquid crystalline polymer used was a versatile Vectra A950. The matrix of composite was composed of PC/PBT 60/40 by weight. A solid epoxy resin (bisphenol type‐A) was used as a compatibilizer for the composites. Dynamic mechanical analysis (DMA) showed that epoxy resin was effective to improve the compatibility between PC and PBT, and between PC/PBT and LCP, respectively. Tensile tests revealed that the stiffness of composites shows little change with the LCP content up to 10 wt %. Above this concentration, the stiffness tended to increase with increasing LCP content. Furthermore, the tensile strengths appeared to increase with increasing LCP content, and their values were close to those predicted from the rule of mixtures. Scanning electron microscopic examination showed that LCP ribbons and short fibrils were developed in the composites containing LCP content ≤10 wt %. However, fine and elongated fibrils were formed in the skin and core sections of the composites when the LCP content reached 25 wt % and above. Thermogravimetric analysis indicated that the thermooxidative stability of the PC/PBT 60/40 blend tended to improve with increasing LCP content. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1827–1835, 1999     

Dynamic‐mechanical analysis of MWNTs‐filled PC/ABS blends

In a systematic manner, the roles of MWNTs as filler and styrene acrylonitrile copolymer‐graft‐maleic anhydride (SAN‐MA) as compatibilizer, individually and together, on dynamic‐mechanical behavior of polycarbonate (PC)‐rich/acrylonitrile butadiene styrene terpolymer (ABS) blend were studied. The investigations were performed using small‐scale mixing in a one‐step procedure with a fixed MWNTs content of 0.75 wt% and a blend composition of PC/ABS = 70/30 w/w. PC/SAN blends and nanocomposites as simpler model system for PC/ABS were also studied to reveal the role of the rubbery polybutadiene (PB) fraction. It is found that the tendency of MWNTs to localize within the PC component in compatibilized PC/ABS was lower than in compatibilized PC/SAN blends. Dynamic mechanical analysis (DMA) revealed the dual role of SAN‐MA as blend compatibilizer and also promoter of MWNTs migration towards PC, where SAN‐MA to MWNTs weight ratio varied between 1 and 4. At the compatibilizer/MWNTs weight ratio of 1, MWNTs localized in PC component of the blends whereas increasing the compatibilizer/MWNTs ratio to 4 led to migration of MWNTs toward SAN or ABS component. In DMA studies, loss modulus normalization of the nanocomposites revealed the coexistence of mobilized and immobilized regions within the nanocomposite structure, as a result of MWNTs and compatibilizer loading. POLYM. ENG. SCI., 54:2696–2706, 2014. © 2014 Society of Plastics Engineers     

Influence of epoxy resin on the properties of maleic anhydride functionalized acrylonitrile–butadiene–styrene copolymer toughened polyamide 6 blends

Maleic anhydride functionalized acrylonitrile–butadiene–styrene copolymer (ABS‐g‐MA) was used as an impact modifier of polyamide 6 (PA6). Epoxy resin was introduced into PA6/ABS‐g‐MA blends to further improve their properties. Notched Izod impact tests showed that the impact strength of PA6/ABS‐g‐MA could be improved from 253 to 800 J/m with the addition of epoxy resin when the ABS‐g‐MA content was set at 25 wt %. Differential scanning calorimetry results showed that the addition of epoxy resin made the crystallization temperature and melting temperature shift to lower temperatures; this indicated the decrease in the PA6 crystallization ability. Dynamic mechanical analysis testing showed that the addition of epoxy resin induced the glass‐transition temperature of PA6 and the styrene‐co‐acrylonitrile copolymer phase to shift to higher temperatures due to the chemical reactions between PA6, ABS‐g‐MA, and epoxy resin. The scanning electron microscopy results indicated that the ABS‐g‐MA copolymer dispersed into the PA6 matrix uniformly and that the phase morphology of the PA6/ABS‐g‐MA blends did not change with the addition of the epoxy resin. Transmission electron microscopy showed that the epoxy resin did not change the deformation mechanisms of the PA6/ABS‐g‐MA blends. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Compatibilizing effect of styrene–maleic anhydride copolymer on the properties of polyamide‐6/liquid crystalline copolyester composites

Liquid crystalline polymer–polyamide‐6 (LCP/PA6) composites containing 20 wt % LCP content were compatibilized by a random styrene–maleic anhydride copolymer (RSMA). The blending was performed via extrusion followed by injection molding. The LCP employed was a commercial copolyester, Vectra A950. The dynamic mechanical (DMA), rheological, thermal, and mechanical properties as well as the morphology of the composites were studied. The DMA and rheological results showed that RSMA is an effective compatibilizer for LCP/PA6 blends. The mechanical measurements showed that the stiffness, tensile strength, and toughness of the in situ composites are generally improved with increasing RSMA content. However, these mechanical properties deteriorated considerably when RSMA content was above 10 wt %. The drop‐weight dart impact test was also applied to analyze the toughening behavior of these composites. The results show that the maximum impact force (F_max) and crack‐initiation energy (E_init) tend to increase with increasing RSMA content. From these results, it appeared that RSMA prolongs the crack‐initiation time and increases the energies for crack initiation and impact fracture, thereby leading to toughening of LCP/PA6 in situ composites. Finally, the correlation between the mechanical properties and morphology of the blends is discussed. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1964–1974, 2000     

Studies on impact‐modified nylon 6/ABS blends

The objective of this research is to study the effect of using maleic anhydride‐grafted polyethylene‐octene elastomer (POE‐g‐MA) as a compatibilizer on nylon 6/acrylonitile‐butadiene‐styrene (ABS) copolymer blends. With POE‐g‐MA, nylon 6/ABS at a blending ratio of 80/20 showed an optimal result in modified impact property. Scanning electron microscopy (SEM) revealed that the particle sizes of ABS in the dispersed phase diminished as the amount of the added compatibilizer (POE‐g‐MA) increased. The compatibilizer reduced the surface tension between nylon 6 and ABS, thus increasing the compatibility of the two phases. Furthermore, studies of the rheological behavior of the system showed that the shear viscosity of nylon 6/ABS blends also increased with the introduction of POE‐g‐MA. Finally, dynamic mechanical analysis (DMA) experiments showed that adding POE‐g‐MA dramatically improved the impact strength of the blends at room temperature and low temperatures. Polym. Eng. Sci. 44:2340–2345, 2004. © 2004 Society of Plastics Engineers.     

Preparation and properties of MWCNTs/poly(acrylonitrile‐ styrene‐butadiene)/epoxy hybrid composites

Poly(acrylonitrile‐styrene‐butadiene) (ABS) was used to modify diglycidyl ether of bisphenol‐A (DGEBA) type epoxy resin, and the modified epoxy resin was used as the matrix for making multiwaled carbon tubes (MWCNTs) reinforced composites and were cured with diamino diphenyl sulfone (DDS) for better mechanical and thermal properties. The samples were characterized by using infrared spectroscopy, pressure volume temperature analyzer (PVT), thermogravimetric analyzer (TGA), dynamic mechanical analyzer (DMA), thermo mechanical analyzer (TMA), universal testing machine (UTM), and scanning electron microscopy (SEM). Infrared spectroscopy was employed to follow the curing progress in epoxy blend and hybrid composites by determining the decrease of the band intensity due to the epoxide groups. Thermal and dimensional stability was not much affected by the addition of MWCNTs. The hybrid composite induces a significant increase in both impact strength (45%) and fracture toughness (56%) of the epoxy matrix. Field emission scanning electron micrographs (FESEM) of fractured surfaces were examined to understand the toughening mechanism. FESEM micrographs reveal a synergetic effect of both ABS and MWCNTs on the toughness of brittle epoxy matrix. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Properties of polycarbonate/acrylonitrile‐butadiene‐styrene/talc composites

The morphology, tensile, impact properties, and thermal expansion behavior of polycarbonate (PC)/acrylonitrile‐styrene‐butadiene (ABS)/talc composites with different compositions and mixing sequences were investigated. From the studies of morphology of the PC/ABS/talc composites, it was observed that some talc particles were located in both the PC and the ABS phases of the blend but most were at the interface between the PC and ABS phases for every mixing sequence. Aspect ratios of the talc particles determined by TEM image analysis reasonably matched values computed from tensile modulus using composite theory. The thermal expansion behavior, or CTE values, was not significantly influenced by the mixing sequence. The impact strength of the PC/ABS/talc composites depended significantly on the mixing sequence; a premix with PC gave the poorest toughness. The molecular weight of the PC in PC/talc composites was found to be significantly decreased. It appears that the impact strength of the PC/ABS/talc composites is seriously compromised by the degradation of the PC caused by talc. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Preparation and properties of TiO2‐filled poly(acrylonitrile‐butadiene‐styrene)/epoxy hybrid composites

Poly (acrylonitrile‐butadiene‐styrene) (ABS) was used to modify diglycidyl ether of bisphenol‐A type of epoxy resin, and the modified epoxy resin was used as the matrix for making TiO₂ reinforced nanocomposites and were cured with diaminodiphenyl sulfone for superior mechanical and thermal properties. The hybrid nanocomposites were characterized by using thermogravimetric analyzer (TGA), dynamic mechanical analyzer (DMA), universal testing machine (UTM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The bulk morphology was carefully analyzed by SEM and TEM and was supported by other techniques. DMA studies revealed that the DDS‐cured epoxy/ABS/TiO₂ hybrid composites systems have two T_gs corresponding to epoxy and ABS rich phases and have better load bearing capacity with the addition of TiO₂ particles. The addition of TiO₂ induces a significant increase in tensile properties, impact strength, and fracture toughness with respect to neat blend matrix. Tensile toughness reveals a twofold increase with the addition of 0.7 wt % TiO₂ filler in the blend matrix with respect to neat blend. SEM micrographs of fractured surfaces establish a synergetic effect of both ABS and TiO₂ components in the epoxy matrix. The phenomenon such us cavitation, crack path deflection, crack pinning, ductile tearing of the thermoplastic, and local plastic deformation of the matrix with some minor agglomerates of TiO₂ are observed. However, between these agglomerates, the particles are separated well and are distributed homogeneously within the polymer matrix. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Mechanical properties and morphology of LCP/ABS blends compatibilized with a styrene–maleic anhydride copolymer

A co‐polyester liquid crystalline polymer (LCP) was melt blended with an acrylonitrile–butadiene–styrene copolymer (ABS). LCP fibrils are formed and a distinct skin/core morphology is observed in the injection moulded samples. At higher LCP concentration (50 wt%), phase inversion occurs, where the dispersed LCP phase becomes a co‐continuous phase. While the tensile strength and Young's modulus remain unchanged with increasing LCP content up to 30 wt% LCP, a significant enhancement of the modulus at 50 wt% LCP is observed due to the formation of co‐continuous morphology. The blend modulus is lower than the values predicted by the rule of mixtures, suggesting a poor interface between the LCP droplets and ABS matrix. A copolymer of styrene and maleic anhydride (SMA) was added in the LCP/ABS blends during melt blending. It is observed that SMA has a compatibilizing effect on the blend system and an optimum SMA content exists for mechanical properties enhancement. SMA improves the interfacial adhesion, whereas excess of SMA reduces the LCP fibrillation. Copyright © 2003 Society of Chemical Industry     

Microstructural characteristics of glass bead‐ and wollastonite‐filled isotactic‐polypropylene composites modified with thermoplastic elastomers

Microstructural characteristics of isotactic‐polypropylene/glass bead (iPP/GB) and iPP/wollastonite (iPP/W) composites modified with thermoplastic elastomers, poly(styrene‐b‐ethylene‐co‐butylene‐b‐styrene) copolymer (SEBS) and corresponding block copolymer grafted with maleic anhydride (SEBS‐g‐MA), were investigated. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and dynamic mechanical analyses (DMA) showed that the iPP/SEBS and iPP/SEBS‐g‐MA blends were partially compatible two‐phase systems. Well‐dispersed spherical GB and acicular W particles without evidence of interfacial adhesion were observed in the iPP/GB and iPP/W binary composites respectively. Contrary to the blends, melt flow rates of the iPP/GB and PP/W composites decreased more with SEBS‐g‐MA than with SEBS because of enhanced interfacial adhesion with SEBS‐g‐MA elastomer. The SEM analyses showed that the ternary composites containing SEBS exhibited separate dispersion of the rigid filler and elastomer particles (i.e., separate microstructure). However, SEBS‐g‐MA elastomer not only encapsulated the spherical GB and acicular W particles completely with strong interfacial adhesion (i.e., core‐shell microstructure) but also dispersed separately throughout iPP matrix. In accordance with the SEM observations, the DSC and DMA revealed quantitatively that the rigid filler and SEBS particles in iPP matrix acted individually, whereas the rigid filler particles in the ternary composites containing SEBS‐g‐MA acted like elastomer particles because of the thick elastomer interlayer around the filler particles. The Fourier transform infrared analyses revealed an esterification reaction inducing the strong interfacial adhesion between the SEBS‐g‐MA phase and the filler particles. POLYM. COMPOS., 31:1265–1284, 2010. © 2009 Society of Plastics Engineers     

In situ composites from blends of polycarbonate and a thermotropic liquid‐crystalline polymer: The influence of the processing temperature on the rheology,morphology, and mechanical properties of injection‐molded microcomposites

This work was aimed at understanding how the injection‐molding temperature affected the final mechanical properties of in situ composite materials based on polycarbonate (PC) reinforced with a liquid‐crystalline polymer (LCP). To that end, the LCP was a copolyester, called Vectra A950 (VA), made of 73 mol % 4‐hydroxybenzoic acid and 27 mol % 6‐hydroxy‐2 naphthoic acid. The injection‐molded PC/VA composites were produced with loadings of 5, 10, and 20 wt % VA at three different processing barrel temperatures (280, 290, and 300°C). When the composite was processed at barrel temperatures of 280 and 290°C, VA provided reinforcement to PC. The resulting injection‐molded structure had a distinct skin–core morphology with unoriented VA in the core. At these barrel temperatures, the viscosity of VA was lower than that of PC. However, when they were processed at 300°C, the VA domains were dispersed mainly in spherical droplets in the PC/VA composites and thus were unable to reinforce the material. The rheological measurements showed that now the viscosity of VA was higher than that of PC at 300°C. This structure development during the injection molding of these composites was manifested in the mechanical properties. The tensile modulus and tensile strength of the PC/VA composites were dependent on the processing temperature and on the VA concentrations. The modulus was maximum in the PC/VA blend with 20 wt % VA processed at 290°C. The Izod impact strength of the composites tended to markedly decrease with increasing VA content. The magnitude of the loss modulus decreased with increasing VA content at a given processing temperature. This was attributed to the anisotropic reinforcement of VA. Similarly, as the VA content increased, the modulus and thus the reinforcing effect were improved comparatively with the processing temperature increasing from 280 to 290°C; this, however, dropped in the case of composites processed at 300°C, at which the modulus anisotropy was reduced. Dynamic oscillatory shear measurements revealed that the viscoelastic properties, that is, the shear storage modulus and shear loss modulus, improved with decreasing processing temperatures and increasing VA contents in the composites. Also, the viscoelastic melt behavior (shear storage modulus and shear loss modulus) indicated that the addition of VA changed the distribution of the longer relaxation times of PC in the PC/VA composites. Thus, the injection‐molding processing temperature played a vital role in optimizing the morphology‐dependent mechanical properties of the polymer/LCP composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Preparation and properties of PC/SAN alloy modified with styrene‐ethylene‐butylene‐styrene block copolymer

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     

Toughening of poly(l‐lactide) modified by a small amount of acrylonitrile−butadiene−styrene core‐shell copolymer

A small amount of acrylonitrile‐butadiene‐styrene (ABS) core shell copolymer particles are used to improve the toughness of poly(l ‐lactide) (PLLA) matrix. The incorporation of ABS copolymer dramatically increased the elongation yield at break of PLLA. For PLLA blend with 6.0 wt % ABS copolymer particles, the elongation yield at break increased by 28 times and the notched impact strength improved by 100% comparing with those of neat PLLA. Fourier transformed infrared (FTIR) and dynamic mechanical analysis (DMA) and scanning electron microscopy (SEM) measurement results indicated that the special polarity interaction between ester group of PLLA matrix and nitrile group of PSAN shell phase enhanced the interfacial adhesion between PB rubber phase and PLLA matrix and promoted the fine dispersion of ABS particles in PLLA matrix. Meanwhile, ABS core shell particles also showed a certain extent of effects on the crystallinity behavior of PLLA. A small amount of ABS particles became the nucleating sites, and then the degree of crystallinity of PLLA/ABS blends increased. However, the notched impact of PLLA blends decreased because of the aggregation of more ABS particles. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42554.     

Development of lightweight thermoplastic composites based on polycarbonate/acrylonitrile–butadiene–styrene copolymer alloys and recycled carbon fiber: Preparation,morphology, and properties

Thermoplastic composites of polycarbonate (PC)/acrylonitrile–butadiene–styrene copolymer (ABS) alloys reinforced with recycled carbon fiber (RCF) were prepared by melt extrusion through a twin‐screw extruder. The RCF was first cleaned and activated with a concentrated solution of nitric acid and was then surface‐coated with diglycidyl ether of bisphenol A as a macromolecular coupling agent. Such an approach is effective to improve the interfacial bonding between the fibers and the PC/ABS matrix. As was expected, the reinforcing potential of the RCF was enhanced substantially, and furthermore, the mechanical properties, heat distortion temperature, and thermal stability of PC/ABS alloys were significantly improved by incorporating this surface‐treated RCF. The composites also obtained a reduction in electrical resistivity. The morphologies of impact fracture surfaces demonstrated that the RCF achieved a homogeneous dispersion in the PC/ABS matrix due to good interfacial adhesion between the fibers and the matrix. In addition, the introduction of RCF into PC/ABS alloys also resulted in an increase in the storage moduli of the composites but a decrease in the loss factors. It is prospective that, with such good performance in mechanical data, heat resistance, and electrostatic discharge, the RCF‐reinforced PC/ABS composites exhibit a potential application in industrial and civil fields as high‐performance and lightweight materials. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Influence of the tert‐dodecyl mercaptan content in poly(acrylonitrile‐butadiene‐styrene) on properties of chlorinated polyvinyl chloride/poly(acrylonitrile‐butadiene‐styrene) blends

A series of poly(acrylonitrile‐butadiene‐styrene) (ABS) grafting modifiers were synthesized by emulsion grafting poly(acrylonitrile‐styrene) (SAN) copolymer onto polybutadiene (PB) latex rubber particles. The chain transfer reagent tert‐dodecyl mercaptan (TDDM) was used to regulate the grafting degree of ABS and the molecular weight of SAN copolymers. By blending these ABS modifiers with Chlorinated polyvinyl chloride (CPVC) resin, a series of CPVC/ABS blends were obtained. The morphology, compatibility, and the mechanical properties of CPVC/ABS blends were investigated. The scanning electron microscope (SEM) studies showed that the ABS domain all uniformly dispersed in CPVC matrix. Dynamic mechanical analyses (DMA) results showed that the compatibility between CPVC and SAN became enhanced with the TDDM content. From the mechanical properties study of the CPVC/ABS blends, it was revealed that the impact strength first increases and then decreases with the TDDM content, which means that the compatibility between CPVC and the SAN was not the only requirement for maximizing toughness. The decreasing of tensile strength and the elongations might attribute to the lower entanglement between chains of CPVC and SAN. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

Blends of poly(2,6‐dimethyl‐1,4‐phenylene oxide)/polyamide 6 toughened by maleated polystyrene‐based copolymers: Mechanical properties,morphology, and rheology

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. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Nanostructured thermosetting epoxy systems modified with poly(isoprene‐b‐methyl metacrylate) diblock copolymer and polyisoprene‐grafted carbon nanotubes

Nanostructured thermosetting composites based on an epoxy matrix modified with poly(isoprene‐b‐methyl methacrylate) (PI‐b‐PMMA) block copolymer were prepared through PI block segregation. Morphological structures were examined by means of atomic microscopy force microscopy. As epoxy/pristine multi‐walled carbon nanotubes (MWCNT) systems were found to present big agglomerations, with a very poor dispersion of the nanofiller, epoxy/PI‐b‐PMMA/MWCNT systems were prepared by using polyisoprene‐grafted carbon nanotubes (PI‐g‐CNT) to enhance compatibility with the matrix and improve dispersion. It was found that the functionalization of MWCNT with grafted polyisoprene was not enough to totally disperse them into the epoxy matrix but an improvement of the dispersion of carbon nanotubes was achieved by nanostructuring epoxy matrix with PI‐b‐PMMA when compared with epoxy/MWCNT composites without nanostructuring. Nevertheless, some agglomerates were still present and the complete dispersion or confinement of nanotubes into desired domains was not achieved. Thermomechanical properties slightly increase with PI‐g‐CNT content for nanostructured samples, whereas for nonnanostructured epoxy/PI‐g‐CNT composites they appeared almost constant and even decreased for the highest nanofiller amount due to the presence of agglomerates. Compression properties slightly decreased with block copolymer content, while remained almost constant with nanofiller amount. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Mechanical and thermal properties of SEBS‐g‐MA compatibilized halloysite nanotubes reinforced polyethylene terephthalate/polycarbonate/nanocomposites

In this study, the effect of maleic anhydride grafted styrene‐ethylene‐butylene‐styrene (SEBS‐g‐MA) content on mechanical, thermal, and morphological properties of polyethylene terephthalate/polycarbonate/halloysite nanotubes (PET/PC/HNTs) nanocomposites has been investigated. Nanocomposites of PET/PC (70 : 30) with 2 phr of HNTs were compounded using the counter rotating twin screw extruder. A series of formulations were prepared by adding 5–20 phr SEBS‐g‐MA to the composites. Incorporation of 5 phr SEBS‐g‐MA into the nanocomposites resulted in the highest tensile and flexural strength. Maximum improvement in the impact strength which is 245% was achieved at 10 phr SEBS‐g‐MA content. The elongation at break increased proportionately with the SEBS‐g‐MA content. However, the tensile and flexural moduli decreased with increasing SEBS‐g‐MA content. Scanning electron microscopy revealed a transition from a brittle fracture to ductile fracture morphology with increasing amount of SEBS‐g‐MA. Transmission electron microscopy showed that the addition of SEBS‐g‐MA into the nanocomposites promoted a better dispersion of HNTs in the matrix. A single glass transition temperature was observed from the differential scanning calorimetry test for compatibilized nanocomposites. Thermogravimetric analysis of PET/PC/HNTs nanocomposites showed high thermal stability at 15 phr SEBS‐g‐MA content. However, on further addition of SEBS‐g‐MA up to 20 phr, thermal stability of the nanocomposites decreased due to the excess amount of SEBS‐g‐MA. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42608.     

Tribological behavior of polyamide 66‐based binary and ternary composites

Friction and wear characteristics of polyamide 66 (PA66) and the composites of organoclay modified by styrene–ethylene/butylene–styrene triblock copolymer grafted with 1.84 wt% of maleic anhydride (SEBS‐g‐MA) were studied using an Universal Micro Tribometer reciprocating friction and wear tester. The morphologies of the wear tracks of PA66 and the composites were observed using a scanning electron microscope. The results showed that plastic deformation induced by the traction of the harder steel ball occurred on the worn surfaces of PA66 and the composite which were reinforced by SEBS‐g‐MA copolymer. It was found that the average frictional coefficient and specific wear rate of PA66/SEBS‐g‐MA binary composite are lowest under the same conditions. This indicates that toughness and wear resistance of PA66 matrix are improved with the incorporation of SEBS‐g‐MA copolymer. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers