Comparison of Stress- and Strain-Induced Polymer Crystallization

Polymer processing is featured with stress-induced crystallization with its microscopic mechanism in competition with stress relaxation. We have set up a platform of molecular simulations on strain-induced polymer crystallization, and studied bulk homopolymers, random copolymers, polymer solutions and blends [1-5]. We further developed a polymer stress relaxation model to gain insights into difference between uniaxial stress- and strain-induced crystallization of homopolymers at various stretching rates and temperatures. We investigated crystallization kinetics and the morphological features with low, medium, and high stretching temperatures. The results show that the stress relaxation of the local chain segment and the overall orientation of the sample has obvious influence on the crystallization behavior at low temperature. The differences between stress- and strain-induced crystallization will facilitate our better understanding of the stress relaxation in polymer processing at the molecular level. The financial support of National Natural Science Foundation of China (Grant No. 21734005) is appreciated!