K-G and Meatballs: Coarse-Grained Simulations of Polymer 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. 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. Software enabling the rapid generation of starting configurations and LAMMPS input files for this class of simulations is available at https://github.com/karnes/K-G-and-Meatballs

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344, release number LLNL-ABS-2008734.