Study on the Thermal and Dielectric Properties of Epoxy Resin Modified by Boron Nitride Nanosheets

With the development of electrothermal density and miniaturization of power equipment, the insulating materials of power equipment are required to possess a better thermal con-ductivity. In order to solve the problem of low thermal conductivity of traditional epoxy resin(EP), boron nitride nanosheep(BNNS) was prepared by stripping hexagonal boron ni-tride and then incorporated into epoxy to obtain nanocomposites. The test results show that BNNS can effectively improve the thermal conductivity of epoxy resin, and the thermal conductivity of EP-BN with a volume fraction of 25% doping ratio is increased by 528% compared with that of pure epoxy resin. By measuring the dielectric spectrum of the com-posites, it is found that the addition of BNNS will increase the dielectric constant and dielectric loss of the composites, but the increase amplitude is not significant, and the in-crease of temperature will also increase the dielectric constant and dielectric loss of the composites. The trap parameters are obtained by analyzing the thermal stimulated current of the composites. BNNS can shallow the trap depth of EP-BN so as to reduce the energy needed for polarization charge generation, resulting in an increase of the dielectric constant and dielectric loss. The increase of temperature will hardly affect the dielectric depth of the material, but can lead to the increase of the amount of trapped charge, which is also mani-fested as the increase of dielectric constant and dielectric loss of the EP-BN. © 2021, High Voltage Engineering Editorial Department of CEPRI. All right reserved.