Environmental Stress Crazing of Rigid Polyvinylchloride

Abstract

The crazing which is induced in various environmental liquids has a very important influence on the long time strength of polymer.
Here, the craze initiating time and the craze propagation rate of rigid polyvinylchloride were measured in various liquids. And the following results were obtained.
(1) The Gibbs' free energy change which was introduced previously by the authors as a parameter to predict the possibility of the environmental stress cracking of polypropylene, could be adapted to the crazing time of rigid polyvinylchloride also.
(2) In the transient region of craze propagation, the relation between the craze length l and time t was expressed by the equation of l=P(t-t₀)^Q, where P and Q were constants. The craze induction period, t₀, was introduced conveniently, which was determinable experimentally.
(3) Under a relatively low stress, the craze propagation rate was very small, and actually no propagation seemed to take place. The actual allowable stress was different depending upon the kinds of environments.