PVC–rubber blends. VI. The structure

Abstract

Abstract The dependence of the dynamic shear modulus of blends of polyvinyl chloride and rubber on the temperature and concentration of the rubber was investigated. For a calculation of a theoretical value of the modulus a formula recently derived by Uemura and Takayanagi was adopted. This formula is based on the assumption of a two‐phase system, in which one phase is a continual matrix and the other is discrete spherical particles, and of perfect adhesion between the phases. Most of the theories that clarify the part played by rubber in rubber‐modified vitreous materials are based on these assumptions. In most cases we have found a good conformity between the theoretical and experimental values of the modulus. In a certain system with an outstanding impact strength, however, a severe discrepancy has been found. This implies that the present structural explanation of the high impact strengths of two‐phase systems is not quite generally applicable.