Thermal conductivity and electric breakdown strength properties of epoxy/ alumina /boron nitride nanosheets composites

摘要

Dielectric polymer composites with high thermal conductivity and high electric breakdown strength are needed for high voltage devices. Epoxy resins is an excellent electrically insulating material, but low thermal conductivity limits its applications. This work aims to effectively enhance the thermal conductivity and keep the breakdown strength of composites as high as possible. In this study, α-alumina (α-Al2O3) particles with an average size of 0.2μm, and boron nitride nanosheets (BNNSs) with an average diameter of 1μm and thickness of around 40nm were homogeneously mixed with epoxy resin, and a three-phase composite was thus obtained. The superiority of this method is that three-phase composites not only show significantly increased thermal conductivity but also have higher breakdown strength in comparison with that of the two-phase α-Al203/epoxy composites. It is clear that epoxy with hybrid fillers has great promising for high thermal conductive insulating materials for the high voltage insulation.