Coarse-grained molecular dynamics simulation on strain-hardening and fracture behaviors of polycarbonate: Effect of polydispersity and spatial distribution

Abstract

Coarse-grained molecular dynamics simulation of polycarbonate is utilized to investigate the relationship between molecular structure (i.e., polydispersity and molecular spatial distribution) and strain-hardening and fracture behavior of polycarbonate. We find that strain-hardening modulus and chain extensibility, which are the constitutive parameters of the Eindhoven Glassy Polymer model are highly affected by spatial distribution but are insensitive to polydispersity. This is attributed to the higher rate of nonaffine deformation in the structure with a high radius of gyration. On the other hand, maximum stress at fracture is highly influenced by both spatial distribution and polydispersity due to the ability to sustain entanglements at larger strain. We suggest the phenomenological expression of maximum stress as a function of the radius of gyration, the number of entanglements, and polydispersity.