Effect of ABS grafting degree and compatibilization on the properties of PBT/ABS blends

Blends of PBT/ABS and PBT/ABS compatibilized with styrene‐acrylonitrile‐glycidyl methacrylate (SAG) copolymer were prepared by melt blending method. Grafting degree (GD) of ABS influences the morphology and mechanical properties of PBT/ABS blends. ABS can disperse in PBT matrix uniformly and PBT/ABS blends fracture in ductile mode when ABS grafting degree is more than 44.8%, otherwise, agglomeration takes place and PBT/ABS blends fracture in brittle way. On the other hand, the grafting degree of ABS has no obvious influence on the morphology of PBT/ABS blends and PBT/ABS blends fracture in ductile mode when SAG is incorporated since the compatibilization effect. However, PBT/SAG/ABS blends display much lower impact strength values comparing with PBT/ABS when the blends fracture in ductile way. Side reactions in PBT/SAG/ABS blends were analyzed and which were the main reason for the decrease of impact strength of PBT blends. Tensile tests show that the tensile strength and tensile modulus of PBT blends decrease with the increase of ABS grafting degree due to the higher effective volume. PBT/SAG/ABS blends display much higher tensile properties than PBT/ABS blends since the compatibilization effect. POLYM. COMPOS., 28:484–492, 2007. © 2007 Society of Plastics Engineers     

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     

Structure–properties relationship in toughening of poly(butylene terephthalate) with core–shell modifier

The performance of acrylonitrile–butadiene–styrene (ABS) core–shell modifier with different grafting degree, acrylonitrile (AN) content, and core–shell ratio in toughening of poly(butylene terephthalate) (PBT) matrix was investigated. Results show PBT/ABS blends fracture in ductile mode when the grafting degree is high, and with the decrease of grafting degree PBT/ABS blends fracture in a brittle way. The surface of rubber particles cannot be covered perfectly for ABS with low grafting degree and agglomeration will take place; on the other hand, the entanglement density between SAN and PBT matrix decreases because of the low grafting degree, inducing poor interfacial adhesion. The compatibility between PBT and ABS results from the strong interaction between PBT and SAN copolymer and the interaction is influenced by AN content. Results show ABS cannot disperse in PBT matrix uniformly when AN content is zero and PBT/ABS fractures in a brittle way. With the addition of AN in ABS, PBT/ABS blends fracture in ductile mode. The core–shell ratio of ABS copolymers has important effect on PBT/ABS blends. When the core–shell ratio is higher than 60/40 or lower than 50/50, agglomeration or cocontinuous structure occurs and PBT/ABS blends display lower impact strength. © 2006 Wiley Periodicals, Inc. J Appl PolymSci 102: 5363–5371, 2006     

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     

Crystallization behavior of PBT/ABS polymer blends

Poly(butylene terephthalate) (PBT) crystallization behavior is modified by blending it with acrylonitrile‐butadiene‐styrene copolymers (ABS). The effects of ABS on melting and crystallization of PBT/ABS blends have been examined. Most ABS copolymers of different rubber content and styrene/acrylonitrile ratios studied showed little effect on the melting behavior of PBT crystalline phase. However, ABS copolymer with high acrylonitrile content had a significant effect on the crystallization behavior of the PBT/ABS blends. The nucleation rate of the PBT crystalline phase decreased due to the presence of the high acrylonitrile content ABS, whereas the spherulitic growth rate increased significantly. These phenomena are attributed to changes in nucleation and growth mechanisms of PBT crystalline phase promoted by ABS. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 423–430, 1999     

Blends of bisphenol A polycarbonate and rubber‐toughened styrene–maleic anhydride copolymers

The morphology and mechanical properties of polycarbonate (PC) blends with rubber‐toughened styrene–maleic anhydride copolymer materials (TSMA) were investigated and compared with the properties of blends of PC with acrylonitrile–butadiene–styrene (ABS) materials. The PC/TSMA blends showed similar composition dependence of properties as the comparable PC/ABS blends. Polycarbonate blends with TSMA exhibited higher notched Izod impact toughness than pure PC under sharp‐notched conditions but the improvements are somewhat less than observed for similar blends with ABS. Since PC is known for its impact toughness except under sharp‐notched conditions, this represents a significant advantage of the rubber‐modified blends. PC blends with styrene–maleic anhydride copolymer (SMA) were compared to those with a styrene–acrylonitrile copolymer (SAN). The trends in blend morphology and mechanical properties were found to be qualitatively similar for the two types of copolymers. PC/SMA blends are nearly transparent or slightly pearlescent. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1508–1515, 1999     

Impact behavior and fracture morphology of acrylonitrile–butadiene–styrene resins toughened by linear random styrene–isoprene–butadiene rubber

A novel toughening modifier, styrene–isoprene–butadiene rubber (SIBR), was used to improve the impact resistance and toughness of acrylonitrile–butadiene–styrene (ABS) resin via bulk polymerization. For comparison, two kinds of ABS samples were prepared: ABS‐1 was toughened by a conventional modifier (a low‐cis polybutadiene rubber/styrene–butadiene block copolymer), and ABS‐2 was toughened by SIBR. The mechanical properties, microstructures of the as‐prepared materials, and fracture surface morphology of the specimens after impact were studied by instrumented notched Izod impact tests and tensile tests, transmission electron microscopy, and scanning electron microscopy, respectively. The mechanical test results show that ABS‐2 had a much higher impact strength and elongation at break than ABS‐1. The microscopic results suggested that fracture resistance of ABS‐1 only depended on voids, shear yielding, and few crazing, which resulted in less ductile fracture behavior. Compared with ABS‐1, ABS toughened by linear random SIBR (ABS‐2) displayed the synergistic toughening effect of crazing and shear yielding, which could absorb and dissipate massive energy, and presented high ductile fracture behavior. These results were also confirmed by instrumented impact tests. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Phase morphology development during processing of compatibilized and uncompatibilized PBT/ABS blends

The development of the multiphase morphology of uncompatibilized blends of poly(butylene terephthalate) (PBT) and acrylonitrile–butadiene–styrene terpolymer (ABS) and PBT/ABS blends compatibilized with methyl‐methacrylate glycidyl‐methacrylate (MMA‐GMA) reactive copolymers during compounding in a twin‐screw extruder and subsequent injection molding was investigated. Uncompatibilized PBT/ABS 60/40 (wt %) and compatibilized PBT/ABS/MMA‐GMA with 2 and 5 wt % of MMA‐GMA showed refined cocontinuous morphologies at the front end of the extruder, which coarsened towards the extruder outlet. Coarsening in uncompatibilized PBT/ABS blends is much more pronounced than in the compatibilized PBT/ABS/MMA‐GMA equivalents and decreases with increasing amounts of the MMA‐GMA. For both systems, significant refinement on the phase morphology was found to occur after the blends pass through the extruder die. This phenomenon was correlated to the capacity of the die in promoting particles break‐up due to the extra elongational stresses developed at the matrix entrance. Injection molding induces coarsening of the ABS domains in the case of uncompatibilized PBT/ABS blends, while the reactive blend kept its refined phase morphology. Therefore, the compatibilization process of PBT/ABS/MMA‐GMA blends take place progressively leading to a further refinement of the phase morphology in the latter steps, owing to the slow reaction rate relative to epoxide functions and the carboxyl/hydroxyl groups. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 102–110, 2007     

Toughening of polyamide 6 with a maleic anhydride functionalized acrylonitrile–butadiene–styrene copolymer

Maleic anhydride functionalized acrylonitrile–butadiene–styrene (ABS‐g‐MA) copolymers were prepared via an emulsion polymerization process. The ABS‐g‐MA copolymers were used to toughen polyamide 6 (PA‐6). Fourier transform infrared results show that the maleic anhydride (MA) grafted onto the polybutadiene phase of acrylonitrile–butadiene–styrene (ABS). Rheological testing identified chemical reactions between PA‐6 and ABS‐g‐MA. Transmission electron microscopy and scanning electron microscopy displayed the compatibilization reactions between MA of ABS‐g‐MA and the amine and/or amide groups of PA‐6 chain ends, which improved the disperse morphology of the ABS‐g‐MA copolymers in the PA‐6 matrix. The blends compatibilized with ABS‐g‐MA exhibited notched impact strengths of more than 900 J/m. A 1 wt % concentration of MA in ABS‐g‐MA appeared sufficient to improve the impact properties and decreased the brittle–ductile transition temperature from 50 to 10°C. Scanning electron microscopy results show that the shear yielding of the PA‐6 matrix was the major toughening mechanism. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Toughening modification of poly(vinyl chloride)/ α‐methylstyrene‐acrylonitrile‐butadiene‐styrene copolymer blends via adding chlorinated polyethylene

In this study, poly (vinyl chloride) (PVC)/α‐methylstyrene‐acrylonitrile‐butadiene‐styrene copolymer (AMS‐ABS) (70/30)/chlorinated polyethylene (CPE) ternary blends was prepared. With the addition of CPE, it did not exert a negative influence in both the glass transition temperature and heat distortion temperature. Thermogravimetric analysis showed that addition of CPE did not play a negative role in the thermal stability. With regard to mechanical properties, high toughness was observed combined with the decrease in tensile strength and flexural strength. With the addition of 15 phr CPE, the impact strength increased by about 21.0 times and 8.5 times in comparison with pure PVC and PVC/AMS‐ABS (70/30) blends, respectively. The morphology correlated well with the impact strength. It was also suggested from the morphology that shear yielding was the major toughening mechanisms for the ternary blends. And there existed a change in the fibril structures that are observed in scanning electron microphotographs. Our present study shows that combination of AMS‐ABS and CPE improves the toughness without sacrificing the heat resistance, and the value of notched impact strength can be enhanced to the same level of super‐tough nylon. POLYM. ENG. SCI., 54:378–385, 2014. © 2013 Society of Plastics Engineers     

Influence of core–shell particles structure on the morphology and brittle‐ductile transition of PBT/ABS‐g‐GMA blends

The performance of glycidyl methacrylate (GMA) functionalized acrylonitrile‐butadiene‐styrene core–shell impact modifiers (R‐ABS) with varied GMA content, crosslinking degree of rubber phase, core–shell ratio, and initiator type in toughening of poly(butylene terephthalate) (PBT) was investigated. Results show that 1 wt% GMA is sufficient to induce a pronounced improvement of the impact strength of PBT and too much GMA induces the crosslinking of R‐ABS. Divinylbenzene improves the crosslinking degree of polybutadiene and decreases its cavitation ability. The brittle‐ductile transition shifts to higher R‐ABS content. When the core–shell ratio of R‐ABS is beyond 70/30, compatibilization reaction is not sufficient to retard the agglomeration of core–shell particles. R‐ABS particles with the core–shell ratio between 50/50 and 60/40 are suitable. Initiator type can influence the internal structure of R‐ABS. For R‐ABS prepared with azobisisobutyronitrile (AIBN) as initiator, big subinclusion structure decreases its toughening ability. R‐ABS prepared with redox initiator shows better toughening behavior. POLYM. COMPOS., 2013. © 2012 Society of Plastics Engineers     

Synthesis of functionalized copolymers and their compatibilization effects on acrylonitrile butadiene styrene/poly(butylene terephthalate) blends

In this study, the copolymers of methyl methacrylate-co-glycidyl methacrylate (MGD) with different epoxy contents and molecular weights, the styrene-co-glycidyl methacrylate (SGD) and methyl methacrylate-co-maleic anhydride (MAD) were synthesized. The synthesized copolymers, styrene-co-maleic anhydride (SMA) and styrene-acrylonitrile-co-glycidyl methacrylate (SAG) were used as compatibilizers to enhance the impact strength of the acrylonitrile butadiene styrene/poly(butylene terephthalate) (ABS/PBT). The effects of differences in the structure, reactive group type, and molecular weight of the compatibilizers on the mechanical properties, phase morphology, melt viscosity, thermal stability, and melting temperature of the blend were studied. The results showed that functionalized copolymers were successfully synthesized with high monomer conversions. Addition of the functionalized copolymers increased melt viscosity but did not considerably affect thermal stability, tensile strength, flexural strength and melting temperature of the ABS/PBT blends. The compatibilizers improved the dispersion of the PBT phase and prevented brittle fracture, thereby increasing the impact strength of the blend. Among the studied compositions, the ABS/PBT/MGD-5 blend exhibited the highest impact strength of 25.8 kJ/m² and an appropriate melt flow index of 19.1 g/10 minutes. The compatibilizer should have an appropriate molecular weight to improve the interface bonding force. Regarding the melting viscosity, the reactive group content and compatibilizer dosage should be adjusted to ensure high impact strength.     

Study of compatibility,morphology structure and mechanical properties of CPVC/ABS blends

Compatibility, morphology structure, and mechanical properties of CPVC/ABS (Chlorinated polyvinyl chloride/acrylonitrile‐butadiene‐styrene) blends were studied. The core‐shell ratios of ABS were set at 40/60 and 70/30. The interface interactions between ABS and CPVC were changed by modifying the acrylonitrile (AN) content of the shell. The compatibility of CPVC with the shell of ABS was studied by the blends of CPVC/SAN with different AN content in SAN. Dynamic mechanical analysis results of CPVC/SAN were in accordance with the morphological properties of CPVC/ABS. The mechanical properties of CPVC/ABS blends in which the polybutadiene content was set to 15 wt % were studied. Results showed, with the change of AN content, the impact strength followed different way for CPVC/ABS blends with different core‐shell ratios of ABS because of the influence of the compatibility. When the core‐shell ratio was 40/60, the CPVC/ABS blends were much ductile in more widely AN range than the blends, whereas the core‐shell ratio of ABS was 70/30. The differences also showed in the SEM micrographs by the investigation of toughening mechanism. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Blends of poly(vinyl chloride) with α‐methylstyrene‐acrylonitrile‐butadiene‐styrene copolymer: Thermal properties,mechanical properties,and morphology

Binary blends of poly(vinyl chloride) (PVC) with α‐methylstyrene‐acrylonitrile‐butadiene‐styrene copolymer (AMS‐ABS) were prepared via melt blending. A single glass transition temperature (T_g) was observed by differential scanning calorimetry, thus indicating that PVC is miscible with the α‐methylstyrene‐acrylonitrile‐styrene in AMS‐ABS. The results from attenuated total reflection Fourier transform infrared spectra indicated that specific strong interactions were not available in the blends. With increasing amounts of AMS‐ABS, both heat distortion temperature and thermal stability were increased considerably. With regard to mechanical properties, flexural and tensile properties decreased with increasing AMS‐ABS content. A synergism was observed in impact strength. The morphology of both impact‐fractured and tensile‐fractured surfaces, observed by scanning electron microscopy, correlated well with the mechanical properties. It is suggested that there was a transition of fracture mechanisms with the changing composition of the binary blends—from shear yielding for blends rich in PVC to cavitation for blends rich in AMS‐ABS. J. VINYL ADDIT. TECHNOL., 19:1–10, 2013. © 2013 Society of Plastics Engineers     

Effects of the polybutadiene/poly(styrene‐co‐acrylonitrile) ratio in a polybutadiene‐g‐poly(styrene‐co‐acrylonitrile) impact modifier on the morphology and mechanical behavior of acrylonitrile–butadiene–styrene blends

Polybutadiene‐g‐poly(styrene‐co‐acrylonitrile) (PB‐g‐SAN) impact modifiers with different polybutadiene (PB)/poly(styrene‐co‐acrylonitrile) (SAN) ratios ranging from 20.5/79.5 to 82.7/17.3 were synthesized by seeded emulsion polymerization. Acrylonitrile–butadiene–styrene (ABS) blends with a constant rubber concentration of 15 wt % were prepared by the blending of these PB‐g‐SAN copolymers and SAN resin. The influence of the PB/SAN ratio in the PB‐g‐SAN impact modifier on the mechanical behavior and phase morphology of ABS blends was investigated. The mechanical tests showed that the impact strength and yield strength of the ABS blends had their maximum values as the PB/SAN ratio in the PB‐g‐SAN copolymer increased. A dynamic mechanical analysis of the ABS blends showed that the glass‐transition temperature of the rubbery phase shifted to a lower temperature, the maximum loss peak height of the rubbery phase increased and then decreased, and the storage modulus of the ABS blends increased with an increase in the PB/SAN ratio in the PB‐g‐SAN impact modifier. The morphological results of the ABS blends showed that the dispersion of rubber particle in the matrix and its internal structure were influenced by the PB/SAN ratio in the PB‐g‐SAN impact modifiers. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2165–2171, 2005     

The effect of recycling number on the mechanical,chemical, thermal,and rheological properties of PBT/PC/ABS ternary blends: With and without glass‐fiber

The recycling possibilities of poly(butylene terephthalate)/polycarbonate/acrylonitrile–butadiene–styrene (PBT/PC/ABS) ternary blend with and without glass‐fiber content were investigated using repeated injection molding process. In this study, PBT/PC/ABS ternary blends were reprocessed at five times and the results were presented after each recycling process. The recycling possibility of PBT/PC/ABS ternary blend was evaluated by measuring the mechanical, chemical, thermal, and rheological properties. Mechanical properties were determined by the tensile strength, yield strength, strain at break, elastic modulus, impact strength, flexural strength, and flexural modulus. Chemical and thermal properties were evaluated by Fourier transform infrared spectroscopy, differential scanning calorimetry, thermal gravimetric analysis, and scanning electron microscopy. Rheological properties of the ternary blends were studied by melt flow index measurement. From the results, it was found that mechanical properties of recycled composites were better than virgin PBT/PC/ABS ternary blends. POLYM. COMPOS., 35:2074–2084, 2014. © 2014 Society of Plastics Engineers     

ABS/SAN/中粘度PMMA三元共混物的性能研究

制备不同配比的丙烯腈－丁二烯－苯乙烯（ABS）／苯乙烯－丙烯腈（SAN）／中粘度聚甲基丙烯酸甲酯（PMMA）合金，分别测试其缺口冲击强度、拉伸强度、热变形温度、熔体流动指数等，结果表明：ABS／SAN可以引发中粘度PMMA产生大量的银纹，从而大幅度提高共混物的冲击强度；引入中粘度PMMA可以提高ABS／SAN的耐热性能；添加中粘度PMMA，合金的流动性能呈现下降的趋势。     

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     

Melt processing,mechanical, and fatigue crack propagation properties of reactively compatibilized blends of polyamide 6 and acrylonitrile–butadiene–styrene copolymer

Within a IUPAC study, melt processing, mechanical, and fatigue crack growth properties of blends of polyamide 6 (PA 6) and poly(acrylonitrile–butadiene–styrene) (ABS) were investigated. We focused on the influence of reactive compatibilization on blend properties using a styrene–acrylonitrile–maleic anhydride random terpolymer (SANMA). Two series of PA 6/ABS blends with 30 wt % PA 6 and 70 wt % PA 6, respectively, were prepared with varying amounts of SANMA. Our experiments revealed that the morphology of the matrix (PA 6 or ABS) strongly affects the blend properties. The viscosity of PA 6/ABS blends monotonically increases with SANMA concentration because of the formation of high‐molecular weight graft copolymers. The extrudate swell of the blends was much larger than that of neat PA 6 and ABS and decreased with increasing SANMA concentrations at a constant extrusion pressure. This observation can be explained by the effect of the capillary number. The fracture resistance of these blends, including specific work to break and impact strength, is lower than that of PA 6 or ABS alone, but increases with SANMA concentration. This effect is most strongly pronounced for blends with 70 wt % PA 6. Fatigue crack growth experiments showed that the addition of 1–2 wt % SANMA enhances the resistance against crack propagation for ABS‐based blends. The correlation between blend composition, morphology and processing/end‐use properties of reactively compatibilized PA 6/ABS blends is discussed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Influence of ABS type on morphology and mechanical properties of PC/ABS blends

The morphology and the mechanical properties of polycarbonate (PC) blends with different acrylonitrile–butadiene–styrene (ABS) materials were investigated. PC/ABS blends based on a mass-made ABS with 16% rubber and large (0.5–1μm) rubber particles are compared to blends based on an emulsion-made ABS with 50% rubber and small, monodisperse (0.12 μm) rubber particles over the full range of blend compositions. The blends with the bulk ABS showed excellent impact strength for most compositions, and those containing 50 and 70% PC exhibited ductile to brittle transition temperatures below that of PC. The blends with the emulsion ABS showed excellent toughness in sharp notch Izod impact tests at room temperature and in standard notch Izod impact tests at low temperatures near the T_g of the rubber. By melt blending the various ABS materials with a styrene–acrylonitrile (SAN 25) copolymer, materials with lower rubber concentrations were obtained. These materials were used in blends with PC to make comparisons at constant rubber concentration of 5, 10, and 15%. The results of this investigation show that brittle ABS materials can produce tough PC–ABS blends. It is apparent that small rubber particles toughen PC–ABS blends at lower rubber concentrations and at lower temperatures than is possible with large rubber particles. However, additional work is needed to understand the nature of toughening in these PC–ABS blends with different rubber phase morphologies. It is of particular interest to understand the exceptional ductility of some of the blends at low temperatures. © 1994 John Wiley & Sons, Inc.