How polymer entanglements retard melt crystallization

Abstract

We performed dynamic Monte Carlo simulations of polymer crystallization to investigate the retardation mechanism of the topological entanglements among chain molecules on the quiescent melt crystallization. Various extents of entanglements in the melts were prepared and were characterized by the average entangled chains around each polymer, with the calculation method similar with the primitive path analysis of polymer entanglements. Kinetic analysis of primary crystal nucleation for melt crystallization revealed that the higher entanglements slightly raise the nucleation barrier assigned to the higher fold-end surface free energy. We found that during crystallization the higher entanglements generate longer loops and tie molecules and thus bring the topological entropic constraints to the folding-end surface of lamellar crystals. The topological constraints furthermore hinder the thickness of lamellar crystals to suppress the harvest of crystallinity. Our observations are consistent with the previously reported phenomena and bring new insights into the microscopic mechanisms of polymer melt crystallization under the influence of the interchain topological entanglements.