Flow-induced crystallization of a polyethylene liquid above the melting temperature and its nonequilibrium phase diagram

Abstract

Manufacturing of plastics is typically performed via flow processing of a polymer melt. Semicrystalline polymers, such as polyethylene (PE), play a critical role in the global plastics markets, but fundamental understanding of how process flow conditions affect their properties is lacking. Nonequilibrium molecular dynamics of a PE liquid above its melting point revealed reversible transitions from coiled, biphasic, stretched, pretransitional, and crystalline phases with applied stress in elongational flow. A nonequilibrium phase diagram was developed for the thermodynamic state space.