Craze Initiation in Rolled Glassy Polycarbonate

Abstract

The crazing phenomenon is one of the most interesting problems in the field of polymer engineering science. Many investigations have been carried out to clarify a criterion for craze initiation. The experiments under conditions of uniaxial and biaxial stress states have showed a critical stress or strain criterion. Almost all of these experiments have been carried out by use of isotropic polymers.It is the purpose of this paper to investigate the craze initiation criterion and yield behavior of anisotropic polycarbonate plates obtained by cold rolling. The stresses of craze initiation and yielding and the craze direction were measured as a function of orientation angle between the tensile axis and the rolling direction, under tension in the presence of kerosene.The results are summarized as follows.(1) Elastic modulus increases with an increase in rolling reduction.(2) Critical crazing strain for rolling direction increases considerably with an increase in rolling reduction.(3) Craze direction varies with the orientation angle. This trend can be explained by the maximum principal strain theory.