Effects of Mechanical Stress on Cohesive Energy and Energy Level Distribution of Bisphenol-A Epoxy Resin

Epoxy resin is widely used in the field of electrical equipment insulation. In this paper, the effects of mechanical stress on cohesive energy and energy level distribution of epoxy resin were investigated. Tensile stress reduces the cohesive energy density of epoxy resin and accelerates the insulation deterioration. On the contrary, the compressive stress can restrain the insulation deterioration. The van der Waals interaction plays a more important role in changing the cohesive energy. The band gap of epoxy resin decreases and the polarizability increases under tensile stress. Under compression stress, the band gap increases and the polarizability decreases. The changes of molecular local state and polarization can affect the charge transport characteristics, which reveals the relationship between the insulation deterioration and the mechanical stress. The conclusion is helpful to understand the insulation failure mechanism of epoxy resin under mechanical stress.