Polypropylene/silica micro‐ and nanocomposites modified with poly(styrene‐b‐ethylene‐co‐butylene‐b‐styrene)

The effects of different silica loadings and elastomeric content on interfacial properties, morphology and mechanical properties of polypropylene/silica 96/4 composites modified with 5, 10, 15, and 20 vol % of poly(styrene‐b‐ethylene‐co‐butylene‐b‐styrene) SEBS added to total composite volume were investigated. Four silica fillers differing in size (nano‐ vs. micro‐) and in surface properties (untreated vs. treated) were chosen as fillers. Elastomer SEBS was added as impact modifier and compatibilizer at the same time. The morphology of ternary polymer composites revealed by light and scanning electron microscopies was compared with morphology predicted models based on interfacial properties. The results indicated that general morphology of composite systems was determined primarily by interfacial properties, whereas the spherulitic morphology of polypropylene matrix was a result of two competitive effects: nucleation effect of filler and solidification effect of elastomer. Tensile and impact strength properties were mainly influenced by combined competetive effects of stiff filler and tough SEBS elastomer. Spherulitic morphology of polypropylene matrix might affect some mechanical properties additionally. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41486.     

Preparation and performance characteristics of short‐glass‐fiber/maleated styrene–ethylene–butylene–styrene/polypropylene hybrid composites

Eighty/twenty polypropylene (PP)/styrene–ethylene–butylene–styrene (SEBS) and 80/20 PP/maleated styrene–ethylene–butylene–styrene (SEBS‐g‐MA) blends reinforced with 30 wt % short glass fibers (SGFs) were prepared by extrusion and subsequent injection molding. The influence of the maleic anhydride (MA) functional group grafted to SEBS on the properties of SGF/SEBS/PP hybrid composites was studied. Tensile and impact tests showed that the SEBS‐g‐MA copolymer improved the yield strength and impact toughness of the hybrid composites. Extensive plastic deformation occurred at the matrix interface layer next to the fibers of the SGF/SEBS‐g‐MA/PP composites during impact testing. This was attributed to the MA functional group, which enhanced the adhesion between SEBS and SGF. Differential scanning calorimetry measurements indicated that SEBS promoted the crystallization of PP spherulites by acting as active nucleation sites. However, the MA functional group grafted to SEBS retarded the crystallization of PP. Finally, polarized optical microscopy observations confirmed the absence of transcrystallinity at the glass‐fiber surfaces of both SGF/SEBS/PP and SGF/SEBS‐g‐MA/PP hybrid composites. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1303–1311, 2002     

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     

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     

Fabrication and properties of carbon nanotube/styrene–ethylene–butylene–styrene composites via a sequential process of (electrostatic adsorption aided dispersion)‐plus‐(melt mixing)

Carbon nanotube (CNT)/styrene–ethylene–butylene–styrene (SEBS) composites were prepared via a sequential process of (electrostatic adsorption assisted dispersion)‐plus‐(melt mixing). It was found that CNTs were uniformly embedded in SEBS matrix and a low percolation threshold was achieved at the CNT concentration of 0.186 vol %. According to thermal gravimetric analysis, the temperatures of 20% and 50% weight loss were improved from 316°C and 352°C of pure SEBS to 439°C and 463°C of the 3 wt % CNT/SEBS composites, respectively. Meanwhile, the tensile strength and elastic modulus were improved by about 75% and 181.2% from 24 and 1.6 MPa of pure SEBS to 42 and 4.5 MPa of the 3 wt % CNT/SEBS composite based on the tensile tests, respectively. Importantly, this simple and low‐cost method shows the potential for the preparation of CNT/polymer composite materials with enhanced electrical, mechanical properties, and thermal stability for industrial applications. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40227.     

Interfacial modification of high impact polystyrene magnesium hydroxide composites effects on flame retardancy properties

High impact polystyrene (HIPS)/magnesium hydroxide (MH) composites were prepared by melt‐blending. Two kinds of interfacial modifiers were used in this research, maleinated poly[styrene‐b‐(ethylene‐co‐butylene)‐b‐styrene] (SEBS‐g‐MA) triblock copolymer and PS. The effects of the use levels of SEBS‐g‐MA on the flame retardancy of HIPS/elastomer/MH based on unmodified and PS‐modified surface were investigated by TEM, FTIR, and combustion tests (horizontal burning test and cone calorimetry). The combustion results showed that comparing composites containing unmodified MH, the flame retarding properties of composites containing PS‐modified MH were obviously improved. The increased performance can be explained that the PS covered on the surface of MH could further improve dispersion of the filler in matrix. Furthermore, there existed a critical thickness of interfacial boundary for optimum flame‐retarding properties in both ternary composites based MH and PS‐modified MH. When the interfacial boundary relative thickness is less than 0.53, the introduction of SEBS‐g‐MA can improve the dispersion degree, leading the improvement of flame retardancy properties. However, with the increase of interfacial boundary thickness, the SEBS‐g‐MA coating around MH acted as a heat and mass transfer barrier, leading to the reduction of flame retardancy. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Effects of maleated styrene–(ethylene‐co‐butene)–styrene on compatibilization and properties of nylon‐12,12/nylon‐6 blends

Effects of a maleated triblock copolymer of styrene–(ethylene‐co‐butene)–styrene (SEBS‐g‐MA) on compatibilization and mechanical properties of nylon‐12,12/nylon‐6 blends were investigated. The results showed that addition of SEBS‐g‐MA could improve the compatibility between nylon‐12,12 and nylon‐6. Nylon‐12,12 could disperse very well in nylon‐6 matrix, although the dispersion of nylon‐6 was poor when nylon‐6 was the dispersed phase. At a fixed nylon‐12,12/nylon‐6 ratio of 30/70, supertoughness was achieved with addition of 15% SEBS‐g‐MA in weight. Scanning electron microscopy of the impact‐fractured surface indicated that cavitation and matrix shear yielding were the predominant mechanisms of impact energy dissipation. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1446–1453, 2004     

Reactive mixing of PET and PET/PP blends with glycidyl methacrylate–modified styrene‐b‐(ethylene‐co‐olefin) block copolymers

Styrene‐b‐(ethylene‐co‐butylene)‐b‐styrene (SEBS) and styrene‐b‐(ethylene‐co‐propylene) (SEP, SEPSEP) block copolymers with different styrene contents and different numbers of blocks in the copolymer chain were functionalized by melt radical grafting with glycidyl methacrylate (GMA) and employed as compatibilizers for PET‐based blends. Binary blends of PET with both functionalized (SEBS‐g‐GMA, SEP‐g‐GMA, SEPSEP‐g‐GMA) and neat (SEBS, SEP, SEPSEP) copolymers (75 : 25 w/w) and ternary blends of PET and PP (75 : 25 w/w) with various amounts (2.5–10 phr) of both modified and unmodified copolymers were prepared in an internal mixer, and their properties were evaluated by SEM, DSC, melt viscosimetry, and tensile and impact tests. The roles of the chemical structure, grafting degree, and concentration of the various copolymers on blend compatibilization was investigated. The blends with the grafted copolymers showed a neat improvement of phase dispersion and interfacial adhesion compared to the blends with nonfunctionalized copolymers. The addition of grafted copolymers resulted in a marked increase in melt viscosity, which was accounted for by the occurrence of chemical reactions between the epoxide groups of GMA and the carboxyl/hydroxyl end groups of PET during melt mixing. Blends with SEPSEP‐g‐GMA and SEBS‐g‐GMA, at concentrations of 5–10 phr, showed a higher compatibilizing effect with enhanced elongation at break and impact resistance. The effectiveness of GMA‐functionalized SEBS was then compared to that of maleic anhydride–grafted SEBS. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2201–2211, 2005     

Morphology and mechanical properties of high‐impact polystyrene/elastomer/magnesium hydroxide composites

Ternary composites of high‐impact polystyrene (HIPS), elastomer, and magnesium hydroxide filler encapsulated by polystyrene were prepared to study the relationships between their structure and mechanical properties. Two kinds of morphology were formed. Separation of elastomer and filler was found when a nonpolar poly[styrene‐b‐(ethylene‐co‐butylene)‐b‐styrene] triblock copolymer (SEBS) was incorporated. Encapsulation of filler by elastomer was achieved by using the corresponding maleinated SEBS (SEBS‐g‐MA). The mechanical properties of ternary composites were strongly dependent on microstructure. In this study, the composites with separate dispersion structure showed higher elongation, modulus and impact strength than those of encapsulation structure. Impact‐fracture surface observation showed that the toughening mechanism was mainly due to the massive cavitation and extensive matrix yielding. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:5184–5190, 2006     

Mechanical properties of wollastonite‐reinforced polypropylene composites modified with SEBS and SEBS‐g‐MA elastomers

Mechanical properties of isotactic polypropylene/wollastonite/styrene rubber block copolymers (iPP/wollastonite/SRBC) composites were studied as a function of elastomeric poly(styrene‐b‐ethylene‐co‐butylene‐b‐styrene) triblock copolymer (SEBS) and SEBS grafted with maleic anhydride (SEBS‐g‐MA) content from 0 to 20 vol%. Microphase morphology was stronger influenced by SRBC elastomers than by different wollastonite types. Higher encapsulation ability of SEBS‐g‐MA than SEBS caused more expressive core‐shell morphology and consequently higher notched impact strength as well as yield parameters, but lower Young's modulus. Higher ductility of the composites with SEBS than with SEBS‐g‐MA has been primarily caused by better miscibility of the polypropylene chains with SEBS molecules. Surface properties of components and adhesion parameters also indicated that adhesion at SEBS‐g‐MA/wollastonite interface, which was stronger than the one at the SEBS/wollastonite interface, influenced higher encapsulation of wollastonite particles by SEBS‐g‐MA. POLYM. ENG. SCI., 47:1873–1880, 2007. © 2007 Society of Plastics Engineers     

Mechanical properties of glass bead‐ and wollastonite‐filled isotactic‐polypropylene composites modified with thermoplastic elastomers

Mechanical properties of the isotactic‐polypropylene/glass bead (iPP/GB) and iPP/wollastonite (iPP/W) composites modified with thermoplastic elastomers, the poly(styrene‐b‐ethylene‐co‐butylene‐b‐styrene) copolymer (SEBS) and corresponding block copolymer grafted with maleic anhydride (SEBS‐g‐MA), were investigated. An increase in toughness of iPP with the elastomers was associated with a decrease in rigidity and strength. Mechanical performance of iPP increased more with acicular W than with spherical GB due to reinforcing effect of W. Comparing the (iPP/GB)/SEBS and (iPP/W)/SEBS composites having the separate microstructure, strength and toughness values of the iPP/GB and iPP/W composites increased more with SEBS‐g‐MA at the expense of rigidity due to the core‐shell microstructure with strong interfacial adhesion. Moreover, the iPP/W composite exhibited superior mechanical performance with 2.5 and 5 vol% of SEBS‐g‐MA because of a positive synergy between the core‐shell microstructure and reinforcing effect of acicular W. The extended models revealed that the elastomer and filler particles in the (iPP/GB)/SEBS and (iPP/W)/SEBS composites acted individually due to the separate microstructure. However, the rigid GB and W particles encapsulated with the thick elastomer interlayer (R₀/R₁ = 0.91) in the (iPP/GB)/SEBS‐g‐MA and (iPP/W)/SEBS‐g‐MA composites acted like neither big elastomer particles nor like individual rigid particles, inferring more complicated failure mechanisms in the core‐shell composites. POLYM. COMPOS., 31:1285–1308, 2010. © 2010 Society of Plastics Engineers     

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     

Rheological behaviors of glass bead‐ and wollastonite‐filled polypropylene composites modified with thermoplastic elastomers

Steady‐ and oscillatory‐shear rheological behaviors of polypropylene/glass bead (PP/GB) and PP/wollastonite (PP/W) melts modified with thermoplastic elastomers, poly(styrene‐b‐ethylene‐co‐butylene‐b‐styrene) copolymer (SEBS) and the corresponding block copolymer grafted with maleic anhydride (SEBS‐g‐MA), were examined by means of a parallel‐plate rheometer. With adding the elastomers (SEBS and SEBS‐g‐MA) and fillers (spherical GB and acicular W) to PP, viscosity especially at low shear rates and shear‐thinning flow behavior at high shear rates were pronounced as evidenced quantitatively by Carreau–Yasuda (CY) parameters, but Cox–Merz analogy became weakened. Besides, melt‐elasticity in terminal region and relaxation time (t_c) in crossing point increased, indicating an enhancement in quasi‐solid behavior of molten PP. Comparing with the elastomers, rheological behaviors of molten PP were more influenced with adding the rigid fillers, especially with W due to distinct acicular shape of W particles. SEBS‐g‐MA elastomer more affected rheological behaviors of the ternary composites than SEBS elastomer, implying that SEBS elastomer and the filler particles behaved individually (i.e., development of separate microstructure) in (PP/GB)/SEBS and (PP/W)/SEBS ternary composites, but core‐shell microstructure developed with strong interfacial adhesion by adding SEBS‐g‐MA elastomer, and the filler particles encapsulated with the thick SEBS‐g‐MA elastomer interlayer (i.e., core‐shell particles) acted like neither big elastomer particles nor like individual rigid particles in melt‐state. Moreover, effects of SEBS‐g‐MA elastomer reached a maximum on rheological behaviors of (PP/W)/SEBS‐g‐MA ternary composite, indicating a synergy between core‐shell microstructure and acicular W particles. Correlations between oscillatory‐shear flow properties and microstructures of the blends and composites were evaluated using Cole–Cole (CC), Han–Chuang (HC), and van Gurp–Palmen (vGP) plots. COMPOS., 2012. © 2012 Society of Plastics     

Mechanical,thermal, and morphological properties of maleic anhydride‐g‐polypropylene compatibilized and chemically modified banana‐fiber‐reinforced polypropylene composites

Composites were prepared with chemically modified banana fibers in polypropylene (PP). The effects of 40‐mm fiber loading and resin modification on the physical, mechanical, thermal, and morphological properties of the composites were evaluated with scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Infrared (IR) spectroscopy, and so on. Maleic anhydride grafted polypropylene (MA‐g‐PP) compatibilizer was used to improve the fiber‐matrix adhesion. SEM studies carried out on fractured specimens indicated poor dispersion in the unmodified fiber composites and improved adhesion and uniform dispersion in the treated composites. A fiber loading of 15 vol % in the treated composites was optimum, with maximum mechanical properties and thermal stability evident. The composite with 5% MA‐g‐PP concentration at a 15% fiber volume showed an 80% increase in impact strength, a 48% increase in flexural strength, a 125% increase in flexural modulus, a 33% increase in tensile strength, and an 82% increase in tensile modulus, whereas the heat deflection temperature increased by 18°C. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Process–structure–property relationship in ternary short‐glass‐fiber/elastomer/polypropylene composites

Short‐glass‐fiber (SGF)‐reinforced polypropylene (PP) composites toughened with a styrene/ethylene butylene/styrene (SEBS) triblock copolymer were injection molded after extrusion. Furthermore, a maleic anhydride (MA)‐grafted SEBS copolymer (SEBS‐g‐MA) was used as an impact modifier and compatibilizer. The effects of the processing conditions and compatibilizer on the microstructure and tensile and impact performance of the hybrid composites were investigated. In the route 1 fabrication process, SGF, PP, and SEBS were blended in an extruder twice, and this was followed by injection molding. In route 2, or the sequential blending process, the elastomer and PP were mixed thoroughly before the addition of SGF. In other words, either PP and SEBS or PP and SEBS‐g‐MA pellets were premixed in an extruder. The produced pellets were then blended with SGF in the extruder, and this was followed by injection molding. The SGF/SEBS‐g‐MA/PP hybrid fabricated by the route 2 process exhibited the highest modulus, yield stress, tensile stress at break, Izod impact energy, and Charpy drop weight impact strength among the composites investigated. This was due to the formation of a homogeneous SEBS elastomeric interlayer at the SGF and matrix interface of the SGF/SEBS‐g‐MA/PP hybrid. This SEBS rubbery layer enhanced the interfacial bonding between SGF and the matrix of the SGF/SEBS‐g‐MA/PP hybrid. The correlations between the processing, microstructure, and properties of the hybrids were investigated. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1384–1392, 2003     

Styrene‐ethylene/butylene‐styrene blends for improved constrained‐layer damping

The influence on the adhesion to some metal surfaces and the damping properties of various modified styrene‐ethylene/butylene‐styrene (SEBS) materials was evaluated. Modification of the different phases of the SEBS with resins was shown to have a large effect on the damping properties of the polymers, which were evaluated by dynamic mechanical analysis (DMA). A small amount of maleic anhydride grafted onto the EB block was found to lead to a significant improvement in the adhesion of the polymer to some metal surfaces without affecting the damping properties of the polymers. The results of the DMA tests on the polymers were used to calculate the composite loss factor (CLF) for a steel laminate, which consisted of two steel plates with a polymeric layer in between, according to the theory proposed by Ross, Ungar, and Kerwin. The calculated results were compared with the measured CLFs determined in vibrating beam tests (VBTs). The agreement between the calculated and measured values was quite fair, provided that the DMA values used for the calculations were recalculated to the actual higher frequencies used in the VBTs, using the time–temperature superposition principle. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2865–2876, 2001     

Effect of poly [styrene‐b‐(ethylene‐co‐butylene)‐b‐styrene] (SEBS) and maleic anhydride‐grafted SEBS triblock copolymers in immiscible blends of (polyamide‐6)/polycarbonate: Morphology‐mechanical properties relationships

The effects of using maleated poly[styrene‐b‐(ethylene‐co‐butylene)‐b‐styrene] triblock copolymer (SEBS‐g‐MAH) and unmodified SEBS (unSEBS) on the phase morphology and mechanical properties of immiscible polymer blends of polyamide‐6 (PA‐6) and polycarbonate (PC) are investigated. Different binary, ternary, and quaternary blends were prepared by using a Brabender® co‐rotating twin‐screw extruder. The weight ratio of unSEBS to SEBS‐g‐MAH was changed to probe the phase morphology and mechanical properties. The results revealed that the mechanical properties of (PA‐6)/PC/(unSEBS/SEBS‐g‐MAH) blends were considerably governed by the unSEBS to SEBS‐g‐MAH weight ratio. Morphological investigation based on the spreading coefficient concept confirmed the results of scanning electron microscopy, indicating encapsulation of unSEBS domains around the PC core‐forming component in the presence of reactive SEBS‐g‐MAH precursor. Moreover, larger unSEBS‐PC composite droplets appeared throughout PA‐6 matrix upon increasing the ratio of unSEBS to SEBS‐g‐MAH, until reaching a maximum value. In the case of the (PA‐6)/PC blend compatibilized with a 50/50 combination of unSEBS and SEBS‐g‐MAH, the highest mechanical properties, i.e., tensile strength, impact resistance, and strain at break, were achieved owing to compatibilizing effect of virgin and maleated SEBS constituents. J. VINYL ADDIT. TECHNOL., 21:245–252, 2015. © 2014 Society of Plastics Engineers     

Influence of the incorporation of fine calcium carbonate particles on the impact strength of polypropylene/polystyrene‐block‐poly(ethylene butene)‐block‐polystyrene blends

The Izod impact strength of two kinds of ternary composites was investigated. One consisted of polypropylene (PP), the triblock copolymer polystyrene‐block‐poly(ethylene butene)‐block‐polystyrene (SEBS), and calcium carbonate (CaCO₃) particles, and the other consisted of PP, carboxylated SEBS (C‐SEBS), and CaCO₃ particles. The mean size of the CaCO₃ particles was about 160 nm. According to scanning electron microscopy observations, the composite with SEBS showed a morphology in which SEBS domains and CaCO₃ particles were independently dispersed in the PP matrix. On the other hand, the composite with C‐SEBS showed a morphology in which CaCO₃ particles were encapsulated by C‐SEBS; that is, a core–shell structure was formed. The Izod impact strength of the composite with SEBS was higher than that of the composite with C‐SEBS and the PP/SEBS and PP/C‐SEBS binary blends. According to observations of the fractured surface, the stress‐whitened area was larger in the composite with SEBS than in the composite with C‐SEBS and the PP/SEBS and PP/C‐SEBS binary blends. The toughening mechanism of the composite, using nanometer‐sized CaCO₃ particles in combination with SEBS, was examined. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Modification of tensile and impact properties of poly(butylene terephthlate) by incorporation of styrene‐ethylene‐butylene‐styrene and maleic anhydride‐grafted‐SEBS (SEBS‐g‐MA) terpolymer

Tensile behavior and impact strength of poly(butylene terephthlate) (PBT)/styrene‐ethylene‐butylene‐styrene (SEBS) copolymer blends were studied at SEBS volume fraction 0–0.38. Tensile modulus and strength decreased, whereas breaking elongation increased with SEBS content. Predictive models are used to evaluate the tensile properties. Strength properties were dependent on the crystallinity of PBT and phase adhesion. The normalized notched Izod impact strength increased with the SEBS content; at Φ_d = 0.38, the impact strength enhanced to five times that of PBT. Scanning electron microscopy was used to examine phase morphology. Concentration and interparticle distance of the dispersed phase influenced impact toughening. In the presence of maleic anhydride‐grafted SEBS (SEBS‐g‐MAH), the tensile modulus and strength decreased significantly, while normalized relative notched Izod impact strength enhanced to 7.5 times because of enhanced interphase adhesion. POLYM. ENG. SCI., 53:2242–2253, 2013. © 2013 Society of Plastics Engineers     

Phase structure and morphology of wollastonite‐reinforced polypropylene composites modified with SEBS and SEBS‐g‐MA elastomers

Supermolecular structure of isotactic polypropylene/wollastonite/styrenic rubber block copolymers composites were studied as a function of elastomeric poly‐ (styrene‐b‐ethylene‐co‐butylene‐b‐styrene) triblock copolymer (SEBS) and the SEBS grafted with maleic anhydride (SEBS‐g‐MA) content (from 0 to 20 vol%) by optical, scanning, and transmission electron microscopy, wide‐angle X‐ray diffraction and differential scanning calorimetry. Wollastonite particles disturbed the spherulitization of polypropylene matrix. Both elastomers affected the crystallization of polypropylene matrix mainly by solidification effect. Although SEBS‐g‐MA encapsulated wollastonite particles more expressive than SEBS forming thus core‐shell morphology in higher extent, scanning electron micrographs indicated more constrained wollastonite particles in fractured surfaces of composites with SEBS elastomer. Moreover, SEBS‐g‐MA disorientated wollastonite particles and affected reorientation of the polypropylene crystallites stronger than SEBS elastomer. POLYM. ENG. SCI., 47:2145–2154, 2007. © 2007 Society of Plastics Engineers