Effect of reactive compatibilizers on the mechanical properties of polycarbonate/poly(acrylonitrile-butadi styrene) blends

Polycarbonate (PC)/poly(acrylonitrile-butadiene-styrene) (ABS) blends compatibilized with both maleic anhydride (MA)-grafted polypropylene and solid epoxy resin (bisphenol type-A) were injection molded. The effects of the compatibilizer additions on the morphology and mechanical properties of the PC/ABS blends were investigated. Tensile and Izod impact tests revealed that the addition of epoxy at 2 phr level to the MA-grafted PC/ABS 70/30 blend led to a significant increase in both tensile ductility and impact strength. Consequently, epoxy content of 2 phr level was added to all the blends investigated. Moreover, tensile tests showed that the yield strength of PC decreased almost linearly with increasing ABS content. However, the tensile modulus showed a positive deviation from the rule of mixtures. Both MA copolymer and epoxy were effective to compatibilize the PC/ABS blends containing ABS content up to 30 wt%. In this case, the impact strength of these compatibilized blends was close to that of PC. Above 40 wt% ABS content, the impact strength of the compatibilized PC/ABS blends decreased significantly. Scanning electron microscopic examination showed that the ABS tends to disperse as large domains in PC matrix of the uncompatibilized PC/ABS blends. However, the size of ABS domains of PC/ABS blends with ABS I 30 wt% was reduced dramatically owing to the incorporation of both compatilizers. (C) 1999 Elsevier Science Ltd. All rights reserved.