Elasto-plastic deformation mechanisms of thermoset glassy polymers depending on the structural characteristic of hardener: A molecular dynamics study

Nanomechanisms of elasto-plastic deformation of epoxy polymer have been investigated considering different types of curing agents using the molecular dynamics simulations. We have conducted uniaxial loading-unloading simulations where strain is applied up to 0.15 to observe the distinct plastic behavior of local chain segments. During the deformation, internal potential components such as pair, bond, angle, torsion, and improper energies have been rigorously monitored and their related molecular movements also observed in microscopic level to investigate the deformation energy accommodation. Specifically, irreversible behavior of internal energy components like pair and torsion has been observed and the behavior of torsional angle becomes prominent in epoxy cured by aromatic curing agent. In line with this trend, contribution of internal potential to the total stress has been derived with seperate consideration on the epoxy resin and curing agent. The profile for the stress also denote the contribution of aromatic curing agent on the irreversible behavior corresponding to the internal energy profiles.