Biaxially strain-induced polymer crystallization studied by dynamic Monte Carlo simulations

Abstract

Polymer crystallization under biaxial stretching is a basic process for rubber-tire strain-hardening performance as well as for plastic film formation. Its specific microscopic mechanism different from that under uniaxial stretching has not yet been systematically investigated. We conducted dynamic Monte Carlo simulations of biaxially strain-induced crystallization in half-half cross-stretched bulk polymers. We found small thermodynamic but significant kinetic differences between biaxially and uniaxially strain-induced polymer crystallizations under the same conditions of strains, temperatures and strain rates. Furthermore, the cross-stretching among neighboring polymers raises a constraint to lamellar thickening in biaxially strain-induced crystallization, which results in low crystallinity and small crystal sizes in agreement with experimental observations. Our simulations brought new insights into a better understanding of biaxially strain-induced polymer crystallization.