Electrical properties of PI films with high thermal conductivity

Abstract

Polyimide (PI) films with excellent mechanical, chemical and high resistance properties, which are a kind of good insulating material in electrical equipment. The electrical equipment is oriented to the design of miniaturization and power maximization, and the high-power electrical equipment working for a long time produces a lot of heat, which results in equipment deformation and insulation layer aging. In this paper, high thermal conductive PI films were prepared by using nanoscale boron nitride (BN) silane coupling agent (KH550) surface modification, nanometer alumina and silica to improve the heat dissipation problem in electrical devices to work for long hours. These thermal conductive fillers are added in polyamide acid (PAA) with different mass ratios during the high thermal conductive PI film preparation. When the mass ratio of 6:2:2, the thermal conductivity filler reaches 10%, and the thermal conductivity of the film reaches 0.72 W/m . K. Moreover, the AC withstands voltage test results show that the AC breakdown electrical field strength of high thermal conductivity composite PI film is 12.6% higher than that of the pure one. The volume resistivity is basically unchanged.