The mechanical properties and creep behavior of epoxy polymer under the marine environment: A molecular dynamics investigation

This study aims to investigate the creep evolution and related performance degradation of epoxy resin polymers in marine environment using molecular simulation. Based on the all-atomic models of epoxy resin, the effect of different moisture absorption rate and different salt solution concentrations on the mechanical properties and creep evolution is studied at several different tensile levels from the micro scale. The present simulation results show that higher moisture absorption rate or salt solution concentration is more likely to lead to creep failure of epoxy system. There is a threshold stress in the creep failure process of epoxy system, and the threshold stress in salt solution environment is lower than that in water environment. The microscopic analysis reveals the movement ability of epoxy resin fragments in the marine environment is stronger than that in the water environment. In the process of creep failure accompanied by energy change, the bond energy of epoxy system remains unchanged, while the non-bond energy increases gradually. These changes of microstructure and energy together determine the macroscopic creep failure of epoxy resin system in marine environment. The results of this study are expected to be a meaningful reference for the practical application of epoxy polymers in marine environment and the further study of creep mechanism.