Molecular simulation of the effect of epoxy side chains on the microstructure and trap characteristics of the cured system

Abstract

Epoxy resin is widely used in power equipment as encapsulation insulation material, but its development and application are affected by its thermal stability, charge accumulation, and poor thermal conductivity. In this paper, epoxy resin’s properties are improved by side-linked grafting, and the microstructure and trap properties of epoxy resin that are grafted with Si-O covalent bond, C-F covalent bond, lipid ring structure, and benzene ring are studied by molecular dynamics method. The simulated structure shows that the epoxy side links do not affect the amorphous structure, but the molecular segment mobility, the number, and the free volume of hydrogen bonds will be affected by the system’s chemical structure. Among them, the introduction of bisphenol AF can increase the free volume of the system, improve molecular segments’ mobility, and affect the formation of hydrogen bonds. Molecular segments’ movement can be inhibited by Alicycles’ introduction. The hydrogen bond energy and hydrogen bond quantity of the system will be increased by the new hydroxyl group’s introduction. The system’s thermal conductivity is reduced by epoxy side links. The grafting of specific polar structures in the epoxy resin system can introduce deep hole traps and shallow electron traps.