Cold rolled ABS. Part 1: The effect of rubber particle size on the tensile properties of ABS before and after cold rolling

The effect of rubber particle size on the tensile properties of rolled and unrolled acrylonitrile‐butadiene‐styrene has been studied by considering model systems consisting of mixtures of a small particle (0.1 micron diam) rubber, S , and a large particle (0.56 micron diam) rubber, L , in an SAN matrix. Before rolling, tensile toughness is characterized by crazing. While both rubber induce matrix crazing, ABS systems containing only the S rubber exhibits early failure due to crack formation, before crazing is propagated very far along the tensile axis. The inefficiency of the small particle rubber is interpreted in terms of high composite yield stress and insufficient distance between particles to allow craze branching. The efficiency of the small particle rubber is improved via the addition of a small amount of large particle, L , rubber to the composite or by a slight degree of cold rolling, both of which enhance craze propagation in the tensile direction. With further rolling, the tensile deformation mode changes from one of localized crazing, which is propagated, to one of uniform deformation, which occurs without crazing.