Molecular-level Plastic Deformation of Polyethylene and Its Dependence on Amorphous Topology

C.R. Locker, J.M. Kim, G.C. Rutledge, A.H. Tsou
ExxonMobil Research and Engineering Co., US

Keywords: molecular dynamics, polyethylene, simulation, deformation

Summary:

Polyethylene (PE) is a semi-crystalline material with a hierarchical morphology and complex deformation behavior. While PE's elastic tensile deformation response can be attributed to the degree of crystallinity, the plastic deformation response, including strain hardening, is typically attributed to the structure of the non-crystalline material. It is difficult to probe this mainly amorphous region experimentally, so molecular-level deformation simulations are used to link the topology within the non-crystalline region to the observed plastic deformation mechanism. Simulation results show that the plastic deformation mechanism depends on the concentration of molecules that link adjacent crystallites, including tie chains and bridging entanglements.