With the development of electrothermal density and miniaturization of power equipment

the insulating materials of power equipment are required to possess a better thermal conductivity. 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 nitride 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 composites

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 increase 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 manifested as the increase of dielectric constant and dielectric loss of the EP–BN.