ABSTRACT
Acrylonitrile-butadiene-styrene (ABS) copolymers are a large family of thermoplastic materials, containing as elastomeric component a polybutadiene-based copolymer, in the form of a dispersed phase in a thermoplastic matrix of poly(styrene-co-acrylonitrile) (SAN). A number of papers have analyzed the behavior of Polycarbonate (PC)/SAN alloys; such analysis is a useful precursor to the analysis of the more complex multicomponent PC/ABS systems. The morphology and the impact resistance were strongly influenced not only by the alloy composition but also by the melt temperature. An alternation of brittle-to-ductile mechanisms with changing alloy composition was observed from both impact curves and fractography. In fact, moving from PC to PC/ABS alloys with increasing ABS content, plain-strain to plain-stress transitions were observed. Fracture occurring parallel to it yielded an inverse herringbone feature, and the alloy toughness decreased in the second instance. The herringbone was determined by interactions of the main crack with secondary cracks started along the center line.
