Rubber-toughening of plastics

Abstract

Mechanisms of deformation in an ABS emulsion polymer were studied quantitatively by a uniaxial tensile creep method. Craze formation was measured in terms of volume strain, which was calculated from simultaneous observations of longitudinal and lateral strains, and shear deformation was measured in terms of lateral strain. The experiments showed that shear deformation predominated during the early stages of creep, but that the rate of shear deformation fell with time. At stresses below 27 MN m⁻², specimens reached extensions of 5% without significant craze formation: at higher stresses, crazing was observed at strains above about 21/2%. Rates of crazing increased with time and with stress, so that the contribution of crazing to creep was greatest during the later stages of the test, and at the higher stresses. The relevance of these results to engineering applications of ABS polymers is discussed.