The Effect of Epoxide on Molecular Chain Relaxation on Bisphenol A Epoxy Resin after Curing

Epoxy resin is widely used as insulating materials in the electric power equipment; however, these properties are affected by the dielectric relaxation greatly. In this paper, three kinds of E51 bisphenol A epoxy resin with different epoxides were used to make samples for differential scanning calorimetry experiment, fourier transform infrared spectroscopy test and broadband dielectric spectroscopy experiment to research the effect of epoxide on molecular chain relaxation. The results demonstrate the relaxation of molecular chain determines the complex permittivity at high frequency when the temperature is over glass transition temperature (
$T_{g}$
). Through fitting the complex permittivity, it is found the molecular chain relaxation of epoxy is dipole relaxation polarization. Epoxy resin with higher epoxide has stronger polarization intensity.