Property enhancement in polypropylene ternary blend nanocomposites via a novel poly(ethylene oxide)‐grafted polystyrene‐block‐poly(ethylene/butylene)‐block‐polystyrene toughener–compatibilizer system

Synthesis and characterization of a novel toughener–compatibilizer for polypropylene (PP)–montmorillonite (MMT) nanocomposites were conducted to provide enhanced mechanical and thermal properties. Poly(ethylene oxide) (PEO) blocks were synthetically grafted onto maleic anhydride‐grafted polystyrene‐block‐poly(ethylene/butylene)‐block‐polystyrene (SEBS‐g‐MA). Special attention was paid to emphasize the effect of PEO‐grafted SEBS (SEBS‐g‐PEO) against SEBS‐g‐MA on morphology, static/dynamic mechanical properties and surface hydrophilicity of the resultant blends and nanocomposites. It was found that the silicate layers of neat MMT are well separated by PEO chains chemically bonded to nonpolar SEBS polymer without needing any organophilic modification of the clay as confirmed by X‐ray diffraction and transmission electron microscopy analyses. From scanning electron microscopy analyses, elastomeric domains interacting with MMT layers via PEO sites were found to be distributed in the PP matrix with higher number and smaller sizes than the corresponding blend. As a benefit of PEO grafting, SEBS‐g‐PEO‐containing nanocomposite exhibited not only higher toughness/impact strength but also increased creep recovery, as compared to corresponding SEBS‐g‐MA‐containing nanocomposite and neat PP. The damping parameter of the same nanocomposite was also found to be high in a broad range of temperatures as another advantage of the SEBS‐g‐PEO toughener–compatibilizer. The water contact angles of the blends and nanocomposites were found to be lower than that of neat hydrophobic PP which is desirable for finishing processes such as dyeing and coating. © 2018 Society of Chemical Industry     

Relationship between structure and properties in high‐performance PA6/SEBS‐g‐MA/(PPO/PS) blends: The role of PPO and PS

This work aimed at studying the role of poly(phenylene oxide) (PPO) and polystyrene (PS) in toughening polyamide‐6 (PA6)/styrene‐ethylene‐butadiene‐styrene block copolymer grafted with maleic anhydride (SEBS‐g‐MA) blends. The effects of weight ratio and content of PPO/PS on the morphology and mechanical behaviors of PA6/SEBS‐g‐MA/(PPO/PS) blends were studied by scanning electron microscope and mechanical tests. Driving by the interfacial tension and the spreading coefficient, the “core–shell” particles formed by PPO/PS (core) and SEBS‐g‐MA (shell) played the key role in toughening the PA6 blends. As PS improved the distribution of the “core–shell” particles due to its low viscosity, and PPO guaranteed the entanglement density of the PPO/PS phase, the 3/1 weight ratio of PPO/PS supplied the blends optimal mechanical properties. Within certain range, the increased content of PPO/PS could supply more efficient toughening particles and bring better mechanical properties. Thus, by adjusting the weight ratio and content of PPO and PS, the PA6/SEBS‐g‐MA/(PPO/PS) blends with excellent impact strength, high tensile strength, and good heat deflection temperature were obtained. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45281.     

Effects of compatibilizer and testing speed on the mechanical and morphology behaviors of co‐continuous amorphous copolyester‐polyoxymethylene blends

Co‐continuous amorphous copolyester (PETG)/polyoxymethylene (POM) (50/50 wt%/wt%) blends were prepared using a twin screw extruder followed compression molding. Two types of thermoplastic polyurethane (TPU) (i.e., polyester‐based and polyether‐based) were used to compatibilize the blends system. The thermal properties were characterized by using differential scanning calorimetry (DSC). The mechanical properties of the co‐continuous PETG/POM blends were studies through flexural and single‐edge notch tensile test (SEN‐T). The SEN‐T test was performed at three different testing speeds; 1, 100, and 500 mm/min. Scanning electron microscope (SEM) was used to access the fracture surface morphology. The flexural strength of the PETG/POM blends was decreased in the presence of TPU. This was attributed to the elastomeric nature of the TPU. The compatibilizing effects of TPU on the PETG/POM blends were proven by moderate improvement in the fracture toughness and confirmed by the SEM observation. The SEN‐T fractured surface of the compatibilized blends showed gross matrix shear yielding as compared to the uncompatibilized system. The K_c values of the PETG/POM blends decreased as the testing speed increased. The optimum toughening effect was observed in PETG/POM blends compatibilized with polyether‐based TPU at testing speed of 100 mm/min. The polyether‐based TPU is a more efficient compatibilizer, because the amount required is one‐half that of the polyester‐based counterpart to achieve the same K_c value. This was attributed to the elastomeric nature of the polyether‐based TPU. The softer nature of polyether‐based TPU could provide better toughening effect than the polyester‐based TPU, which is relatively harder in nature. POLYM. ENG. SCI., 45:710–719, 2005. © 2005 Society of Plastics Engineers     

Polyoxymethylene/thermoplastic polyurethane blends compatibilized with multifunctional chain extender

Novel compatibilized polyoxymethylene/thermoplastic polyurethane (POM/TPU) blends are successfully developed using multifunctional chain extender, Joncryl ADR‐4368, as the compatibilizer. The outstanding compatibilization efficiency of Joncryl on POM/TPU blend was demonstrated by its even higher mechanical properties with only 0.5 wt % of Joncryl than those with 5 wt % of three commonly used compatibilizers. Addition of only 0.5 wt % Joncryl can double the impact strength and significantly improve its tensile strength and flexural strength for POM/TPU (75/25) blend. SEM images show that Joncryl can reduce TPU particle size and enhance the interfacial interactions between POM and TPU. The interparticle distance of TPU in POM/TPU/Joncryl blends was calculated as 0.2 μm, quite close to the critical matrix ligament thickness of POM/TPU blends (0.18 μm). The impact force profile vividly shows that the addition of Joncyl in POM/TPU blends can dramatically increase the total impact energy absorbed by this blend system and enhance the interfacial interactions between POM and TPU. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Acid‐modified carbon nanotubes distribution and mechanical enhancement in polystyrene/elastomer blends

The incorporation of carbon nanotubes (CNTs) is expected as an effective path for tailoring mechanical properties of polymer blends. In this study, acid‐modified multiwalled CNTs (A‐MWCNTs) were introduced into polystyrene/maleic anhydride‐g‐(styrene‐ethylene‐butadiene‐styrene) (PS/SEBS‐MA) blends. By altering the mass ratio of PS/SEBS‐MA from 80/20 to 60/40, the biphase structure of blend was changed from sea‐island‐like type to quasi co‐continuous structure, of different mechanical behaviors. In 80/20 mass ratio, the impact strength was improved while the tensile strength was unchanged with increasing A‐MWCNTs content, whereas a simultaneously toughening and strengthening effect was achieved for the compound with 60/40 mass ratio. Scanning electron microscopy, polarized light microscopy, dynamic mechanical analysis, and rheological measurements were carried out to detect the distribution of A‐MWCNTs in the blends. The results demonstrated as increasing the nanotube loading from 0 to 3 wt%, A‐MWCNTs might gradually migrate into continuous PS phase in 80/20 mass ratio, due to the low content of SEBS‐MA, while they were totally packed in SEBS‐MA region within the entire loading range used in 60/40 mass ratio due to its high content of SEBS‐MA. This study provides guidance on the design and preparation of high performance ternary polymer/elastomer/inorganic filler composites. POLYM. ENG. SCI., 2012. © 2011 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     

Development and characterization of green composites from bio‐based polyethylene and peanut shell

In the present work, different compatibilizers, namely polyethylene‐graft‐maleic anhydride (PE‐g‐MA), polypropylene‐graft‐maleic anhydride (PP‐g‐MA), and polystyrene‐block‐poly(ethylene‐ran‐butylene)‐block‐polystyrene‐graft‐maleic anhydride (SEBS‐g‐MA) were used on green composites derived from biobased polyethylene and peanut shell (PNS) flour to improve particle–polymer interaction. Composites of high‐density polyethylene/peanut shell powder (HDPE/PNS) with 10 wt % PNS flour were compatibilized with 3 wt % of the abovementioned compatibilizers. As per the results, PP‐g‐MA copolymer lead to best optimized properties as evidenced by mechanical characterization. In addition, best particle–matrix interface interactions with PP‐g‐MA were observed by scanning electron microscopy (SEM). Subsequently HDPE/PNS composites with varying PNS flour content in the 5–30 wt % range with PP‐g‐MA compatibilizer were obtained by melt extrusion and compounding followed by injection molding and were characterized by mechanical, thermal, and morphological techniques. The results showed that PNS powder, leads to an increase in mechanical resistant properties (mainly, flexural modulus, and strength) while a decrease in mechanical ductile properties, that is, elongation at break and impact absorbed energy is observed with increasing PNS flour content. Furthermore, PNS flour provides an increase in thermal stability due to the natural antioxidant properties of PNS. In particular, composites containing 30 wt % PNS powder present a flexural strength 24% and a flexural modulus 72% higher than the unfilled polyethylene and the thermo‐oxidative onset degradation temperature is increased from 232 °C up to 254 °C thus indicating a marked thermal stabilization effect. Resultant composites can show a great deal of potential as base materials for wood plastic composites. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43940.     

Compatibilizing Effect of SEBS for Electrical Properties of LDPE/PS Blends

Summary: In the previous study, we observed compatibilizing effects of low density polyethylene (LDPE)/polystyrene (PS) with polystyrene‐block‐poly(ethylene‐co‐butylene)‐block‐polystyrene (SEBS), a triblock copolymer. Blends consisting of 70 wt.‐% LDPE and 30 wt.‐% PS were prepared with a SEBS concentration of up to 10 wt.‐%. This study examined the electrical properties such as the electrical breakdown, water tree length, permittivity and tan δ in the blends. The possibility of using these blends as insulating material substitutes for LDPE was investigated. The electrical breakdown strength reached a maximum of 66.67 kV/mm, which is superior to 50.27 kV/mm of the LDPE used as electrical insulators for cables. In addition, the water tree length decreased with increasing SEBS concentration. The water tree lengths of the blends containing SEBS were shorter than that of the LDPE. The permittivity of the blends was 2.28–2.48 F/m, and decreased with increasing SEBS concentration with the exception of S‐0. Tan δ of the blends increased smoothly with increasing SEBS content.

Breakdown strength , water tree length, permittivity and tan δ of the LDPE/PS/SEBS blends and raw materials.     

Characteristics of impact modified polystyrene/organoclay nanocomposites

The poor impact resistance of Polystyrene (PS) was enhanced by the addition of elastomeric material, SEBS‐g‐MA. To prevent the reduction in strength and stiffness, organoclay Cloisite® 25A was used as filler and introduced into the matrix by a corotating twin screw extruder. Throughout the study, the clay content was kept at 2 wt%, whereas the content of SEBS‐g‐MA was varied between 5 and 40 wt%. It was found that Cloisite® 25A displays well dispersion in the ternary nanocomposites and the degree of dispersion increases with the elastomer content. The elastomeric phase has a greater viscosity than pure PS. Thus, as expected, at low elastomer contents, it forms the dispersed phase in the matrix as droplets. Transmission electron microscopy results show that the clay layers reside at the interphase between PS and elastomer and also inside the elastomeric phase. Owing to the location of the clay particles, the average elastomer domain size in ternary nanocomposites are found to be greater than that in the relative binary blends of PS‐(SEBS‐g‐MA). Moreover, with the organoclay addition, phase inversion point shifts to lower elastomer contents. The mechanical test results showed that the nanocomposites containing 15 and 20 wt% SEBS‐g‐MA have the optimum average domain size that results in high‐impact strength values without deteriorating the tensile properties. POLYM. COMPOS., 31:1853–1861, 2010. © 2010 Society of Plastics Engineers.     

Deformation mechanism of polystyrene toughened with sub‐micrometer monodisperse rubber particles

Core–shell polybutadiene‐graft‐polystyrene (PB‐g‐PS) rubber particles with different ratios of polybutadiene to polystyrene were prepared by emulsion polymerization through grafting styrene onto polybutadiene latex. The weight ratio of polybutadiene to polystyrene ranged from 50/50 to 90/10. These core‐shell rubber particles were then blended with polystyrene to prepare PS/PB‐g‐PS blends with a constant rubber content of 20 wt%. PB‐g‐PS particles with a lower PB/PS ratio (≤70/30) form a homogeneous dispersion in the polystyrene matrix, and the Izod notched impact strength of these blends is higher than that of commercial high‐impact polystyrene (HIPS). It is generally accepted that polystyrene can only be toughened effectively by 1–3 µm rubber particles through a toughening mechanism of multiple crazings. However, the experimental results show that polystyrene can actually be toughened by monodisperse sub‐micrometer rubber particles. Scanning electron micrographs of the fracture surface and stress‐whitening zone of blends with a PB/PS ratio of 70/30 in PB‐g‐PS copolymer reveal a novel toughening mechanism of modified polystyrene, which may be shear yielding of the matrix, promoted by cavitation. Subsequently, a compression‐induced activation method was explored to compare the PS/PB‐g‐PS blends with commercial HIPS, and the result show that the toughening mechanisms of the two samples are different. Copyright © 2006 Society of Chemical Industry     

Effect of crystalline microstructure near the particle/matrix interface on the toughening of syndiotactic polystyrene/polyamide‐6 blends

Toughening behavior of semicrystalline polymers was investigated using syndiotactic polystyrene (sPS)/polyamide 6(PA‐6) blends compatibilized with maleic‐anhydride functionalized poly (styrene‐b‐(ethylene‐co‐butylene)‐b‐styrene) SEBS‐MA triblock copolymer. The effect of interparticle distance and crystal microstructure near the particle/matrix interface of the blends were studied. The morphology studies revealed that the size and interparticle distance of the dispersed PA‐6 particles decreased with increasing SEBS‐MA concentration. sPS/PA‐6 blends exhibited sharp brittle‐ductile transitions at a critical interparticle distance of 0.25 μm. With the increase of the compatibilizer concentration beyond a certain level, it was observed that the further addition resulted in decreased impact strength. This could be attributed to the formation of a separate phase in the matrix by the additional SEBS added. The TEM studies showed that when the interparticle distance is below 0.25 μm, the matrix ligaments between the inclusions will be filled with well‐oriented crystalline material of reduced plastic resistance. From DSC and X‐ray diffraction studies of model thin films, it was found that the fraction of small and imperfect crystallites near the particle/matrix interface increased with decreasing interparticle distance. This resulted in decreased yield stress of the whole matrix with increasing concentration of SEBS‐MA accompanied by changes in the fracture mode from brittle to tough. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Effects of carbon nanofibers on the fracture,mechanical, and thermal properties of PP/SEBS‐g‐MA blends

Polypropylene/maleated (styrene‐ethylene‐butadiene‐styrene) (PP/SEBS‐g‐MA) blends reinforced with 0.2–2.5 wt% carbon nanofibers (CNFs) were prepared by injection molding. The structure, thermal, mechanical, and fracture behaviors of PP/SEBS‐g‐MA blends and their nanocomposites were studied. Wide‐angle X‐ray diffraction (WAXD) results showed that the SEBS‐g‐MA and/or CNF additions do not induce a structural change of PP. Tensile measurements showed that the Young's modulus and tensile yield strength increase with the increasing filler content. Izod impact and essential work of fracture test results demonstrated that CNFs are beneficial to improve the impact strength and specific essential work of fracture of PP/SEBS‐g‐MA blends. Therefore, tough PP‐nanocomposites can be achieved by melt‐blending low fractions of CNFs and appropriate elastomer contents. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

Toughening of polylactic acid using styrene ethylene butylene styrene: Mechanical,thermal, and morphological studies

Polylactic acid, PLA, derived from renewable resources has gained great attention nowadays owing to their sustainability, biodegradability, superior property, and transparency. However, intrinsic brittleness and low toughness severely limits its variety of applications. Blending of PLA with other polymers is more economical and more flexible technique for the property improvement of PLA. In this study, Styrene Ethylene Butylene Styrene (SEBS) and Maleic Anhydride grafted SEBS (MA‐g‐SEBS) are used as toughening agents to study their effect for its toughness, high strength and heat resistance on PLA. PLA/SEBS and PLA/Maleic Anhydride grafted SEBS blends were prepared under four different compositions by melt mixing technique using a corotating twin–screw extruder after optimizing the mixing conditions. The mechanical properties of the blends such as tensile, flexural, and impact strengths were investigated using specimens prepared by injection molding process. The percentage elongation and impact strength of PLA/MA‐g‐SEBS blends were found to be increased significantly by 540 and 135%, respectively in comparison with virgin PLA and PLA/SEBS blends. However, tensile strength and modulus of PLA/SEBS and PLA/MA‐g‐SEBS blends decreased compared with pristine PLA. SEM behaviour supported the higher impact property of PLA with the incorporation of modified SEBS via multiple crazing and cavitation mechanisms. DSC study also supported greater compatibility between maleated SEBS and PLA. POLYM. ENG. SCI., 56:669–675, 2016. © 2016 Society of Plastics Engineers     

Toughened polyoxymethylene by polyolefin elastomer and glycidyl methacrylate grafted high‐density polyethylene

Ternary blends of polyoxymethylene (POM), polyolefin elastomer (POE), and glycidyl methacrylate grafted high density polyethylene (GMA‐g‐HDPE) with various component ratios were studied for their mechanical and thermal properties. The size of POE dispersed phase increased with increasing the elastomer content due to the observed agglomeration. The notched impact strength demonstrated a parabolic tendency with increasing the elastomer content and reached the peak value of 10.81 kJ/m² when the elastomer addition was 7.5 wt%. The disappearance of epoxy functional groups in the POM/POE/GMA‐g‐HDPE blends indicated that GMA‐g‐HDPE reacted with the terminal hydroxyl groups of POM and formed a new graft copolymer. Higher thermal stability was observed in the modified POM. Both storage modulus and loss modulus decreased from dynamic mechanical analysis tests while the loss factor increased with increasing the elastomer content. GMA‐g‐HDPE showed good compatibility between the POM matrix and the POE dispersed phase due to the reactive compatibilization of the epoxy groups of GMA and the terminal hydroxyl groups of POM. A POM/POE blend without compatibilizer was researched for comparison, it was found that the properties of P‐7.5(POM/POE 92.5 wt%/7.5 wt%) were worse than those of the blend with the GMA‐g‐HDPE compatibilizer. POLYM. ENG. SCI., 57:1119–1126, 2017. © 2017 Society of Plastics Engineers     

Morphology and mechanical properties of polyamide 12 blends with styrene/ethylene–butylene/styrene rubbers with and without maleation

Blends of polyamide 12 (PA12) with styrene/ethylene–butylene/styrene (SEBS) and maleic anhydride grafted SEBS (SEBS‐g‐MA) were prepared by twin‐screw extrusion and injection molding. The morphology, mechanical properties, and dynamic mechanical properties of the blends were studied. The morphology of the blends was evaluated from the etched surfaces of cryogenically fractured specimens with scanning electron microscopy. The morphological parameters showed that the PA12/SEBS‐g‐MA blends (PM series) exhibited a finer and more uniform rubber dispersion than the PA12/SEBS blends (PS series) because of the interfacial chemical reactions. SEBS functionalization via maleic anhydride grafting strongly affected the morphological parameters, such as the domain size, interfacial area per unit of volume, and critical interparticle distance, but the distribution of the rubber domains in the blends was less affected. Tensile and impact studies showed that the PS blends had worse mechanical properties than the PM blends. The tensile strength and elongation at break of the PM blends were considerably greater than those of the PS blends. The fracture toughness and energy values determined for notched Charpy specimens in high‐speed impact tests were markedly higher for the PM blends than for the PS blends. A similar observation was obtained from instrumented falling weight impact studies. Dynamic mechanical analysis confirmed the incompatibility of the blend components because the glass‐transition temperatures of PA12 and the rubber phase (SEBS and SEBS‐g‐MA) were not affected. © 2005 Wiley Periodicals, Inc. J Appl polym Sci 95: 1376–1387, 2005     

Toughening and compatibilization of polyphenylene sulfide/nylon 66 blends with SEBS and maleic anhydride grafted SEBS triblock copolymers

In this study, styrene‐b‐ethylene/butylene‐b‐styrene triblock copolymer (SEBS) and maleic anhydride grafted SEBS (SEBS‐g‐MA) were used as compatibilizers for the blends of polyphenylene sulfide/nylon 66 (PPS/PA66). The mechanical properties, including impact and tensile properties and morphology of the blends, were investigated by mechanical properties measurements and scanning electron microscopy. Impact measurements indicated that the impact strength of the blends increases slowly with elastomer (SEBS and SEBS‐g‐MA) content upto 20 wt %; thereafter, it increases sharply with increasing elastomer content. The impact energy of the elastomer‐compatibilized PPS/PA66 blends exceeded that of pure nylon 66, implying that the nylon 66 can be further toughened by the incorporation of brittle PPS minor phase in the presence of SEBS or SEBS‐g‐MA. The compatibilization efficiency of SEBS‐g‐MA for nylon‐rich PPS/PA66 was found to be higher than SEBS due to the in situ forming SEBS interphase between PPS and nylon 66. The correlation between the impact property and morphology of the SEBS‐g‐MA compatibilized PPS/PA66 blends is discussed. The excellent impact strength of the nylon‐rich blends resulted from shield yielding of the matrix. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Environmental weathering of (linear low‐density polyethylene)/(soya powder) blends compatibilized with polyethylene‐grafted maleic anhydride

Blends containing various percentages of linear low‐density polyethylene and soya powder were prepared. The effects of polyethylene‐graft‐(maleic anhydride) (PE‐g‐MA) as a compatibilizer and soya powder content on the natural weathering were investigated. Blends without PE‐g‐MA were used as controls. The soya powder was varied from 5 to 40 wt% of the blends, and PE‐g‐MA was used at 50 wt% based on soya powder content. The samples were exposed to natural weathering in the northern part of Malaysia for 1 year. Higher decreases in tensile strength and elongation at break of the controls were observed as compared to those of the PE‐g‐MA compatibilized blends after the natural weathering. The Young's modulus of both controls and compatibilized blends increased over the environmental exposure period. A control sample lost 8.8% of its original weight after 1 year of weathering, whereas a compatibilized blend lost 7.5 wt% during the same period. J. VINYL ADDIT. TECHNOL., 2012. © 2012 Society of Plastics Engineers     

Impact modification of polyacetal by thermoplastic elastomer polyurethane

The main goal of this study was impact modification of polyacetal [polyoxymethylene (POM)] with thermoplastic elastomer polyurethane (TPU). We modified the impact strength of POM 10‐fold. The mechanical properties, thermal behavior, and morphology of POM/TPU blends consisting of 5 to 50% of TPU were studied. It was found that the best impact modification of the blends was at 15% concentration of TPU and the maximum elongation at break was at 30% concentration of TPU. The impact strength of POM/TPU blends can be improved by using diphenylmethane diisocyanate (MDI) as compatibilizer. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2573–2582, 2002     

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     

Morphology of nylon 1212 toughened with a maleated EPDM rubber

BACKGROUND: Polyamides, or nylons, are an attractive class of engineering polymers due to their excellent strength and stiffness, low friction and chemical and wear resistance. However, they are highly notch‐sensitive, i.e. they are often ductile in the un‐notched state, but fail in a brittle manner when notched. A super‐tough nylon 1212 was prepared by blending nylon 1212 with ethylene propylene diene monomer (EPDM) grafted with maleic anhydride (MA). The morphologies of Izod impact fracture surfaces as well as xylene‐etched surfaces of the nylon were thoroughly investigated using scanning electron microscopy (SEM). RESULTS: The fracture morphology and the impact strength of the nylon 1212 blends are very well correlated. The impact fracture surface of the blends exhibits certain characteristic features, such as the observation of fiber‐like sticks when etched with boiling xylene, formed during the impact fracture process. SEM images of xylene‐etched surfaces as well as the results of X‐ray energy dispersive spectroscopy suggest that the successful toughening of nylon 1212 with EPDM‐graft‐MA is due to the reaction between the anhydride of EPDM‐graft‐MA and the amine end‐groups of nylon 1212, leading to the formation of a homogenous graft copolymer system. CONCLUSION: The copolymer system, acting as a surfactant, reduces the interfacial tension between nylon 1212 and EPDM‐graft‐MA and produces a highly compatible super‐tough nylon 1212. Copyright © 2008 Society of Chemical Industry