On void formation during the simulated tensile testing of polymer-filler particle composites

We simulate a series of model polymer composites, composed of linear polymer strands and spherical, monodisperse filler particles (FP). These molecular dynamics simulations implement a coarse-grained, bead-spring force field and we vary several formulation parameters to study their respective influences on material properties. These parameters include FP radius, FP volume fraction, temperature, and the polymer-polymer, FP-FP, and polymer-FP interaction potentials. Uniaxial extension of the simulation cells allows direct comparison of mechanical reinforcement (or weakening) provided by the FP. We focus on the formation of microscopic voids during simulated tensile testing of glassy polymer composites and quantify how the characteristic spatial and morphological arrangement of these voids is a function of interaction potentials used in the simulation. We discuss the implications of these findings in the context of polymer composite design and formulation.