CRACK INITIATION AND FIBER CREEP IN POLYETHYLENE

A critical appraisal has been carried out of the creep performance of the fibrils in the pre-crack damage zone (craze) of a series of polyethylene homo- and copolymers. It has been shown that by assuming that the fibrils are drawn to the natural draw ratio of the material, a correlation can be established between the creep rate of oriented specimens and the stress crack performance of the material. The existence of such a correlation paves the way to simpler and faster testing routines and to a better understanding of the factors controlling stress crack performance.