Effects of frequency and thermal conductivity on dielectric breakdown characteristics of epoxy/cellulose/BN composites fabricated by ice-templated method

Epoxy resin has been extensively used in the electrical systems and electronic devices. However, it is still a challenge to fabricate highly thermally conductive but electrically insulating epoxy composites. In this work, epoxy/cellulose/BN (EP/C-BN) composites were fabricated by ice-templated method. More importantly, the effects of frequency and thermal conductivity on dielectric breakdown characteristics, supported by the experiments of dielectric breakdown characteristics, infrared thermal imaging and finite simulation analysis, were studied. The as-prepared EP/C-BN composites exhibit a maximum thermal conductivity of 1.19 W/(m·K), and notably improved breakdown time at high frequency (324% higher than that of EP at 44 kHz). This work gives significant insight into the design of the thermal management polymers working at high frequency and high voltage fields.