The formation of translucent cold‐drawn polypropylene

Abstract The behavior of quenched samples of polypropylene subjected to stress relax–reload cycles during cold drawing has been investigated as a function of quench severity and strain rate. Results obtained by cooling the propagating neck of a drawing sample are also discussed. A translucent cold‐drawn form of the polymer, characterized by a small microvoid content, is observed when the propagating neck boundary is cooled or when stress relax–reload cycles are carried out at sufficiently high strain rates. A small mobility of the chains relative to the local strain rate is postulated as necessary for the formation of the translucent material.