Crazing of polycarbonate at cryogenic temperature: Effect of specimen thickness

Abstract Polycarbonate sheets of varying thickness were subjected to tensile testing in a nitrogen environment at 77 K. Crazes were detected in the thinnest specimens, but the tendency to craze diminished with increasing specimen thickness. Diffusion of the environment into the skin layer of the specimen, as a proportion of the total thickness of the stressed system, is considered to have a major effect on the probability of crazing. A sandwich model, consisting of plasticized skin layer through diffusion of the environment and unplasticized core, is developed to account for the observations.