Prediction of mechanical properties of EPON 862 (DGEBF)-W (DETDA) using MD simulations

The present study). A quad oligomer of DEGBF cross-linked with DETDA was used for the calculations. A MD model of the epoxy was built using the amorphous module of Material Studio (Accelrys Inc.). The Polymer Consistent Force Field (PCFF) was used in the simulation. The amorphous structure was achieved by giving periodic boundary conditions and then subjected to an energy minimization using the ensemble of the constant-volume and temperature (NVT). The structure was equilibrated for 100 picoseconds (ps) followed by a MD equilibration at room temperature for another 200 ps. Since at room temperature most of the atoms are in static mode, the atoms were excited using simulation temperatures above the glass transition temperatures. In an attempt of finding the global energy minimum, simulated annealing runs were carried out starting at elevated temperatures and atmospheric pressure using the ensembles of the constant number of particles, constant-pressure and constant temperature (NPT). The temperature was gradually lowered to room temperature level. Each subsequent simulation was started from the final configuration obtained at the preceding temperature. Density of the epoxy at each temperature was calculated from the average specific volume and glass transition temperature (T g) was estimated based on the discontinuity in the slope of the density-temperature plot. The amorphous structure obtained at room temperature was analyzed to determine the fundamental mechanical properties of EPON 862-W. Copyright © 2010 by the American Institute of Aeronautics and Astronautics, Inc.