Study of Thermal Conductivity and Dielectric Properties of Electrospun Epoxy Resin Composites

Driven by the swift advancement of energy vehicle drive motor technology, higher requirements have been put forward for the heat dissipation and insulation of potting materials under high power density. The lower thermal conductivity (TC) of epoxy resin (EP) as an encapsulation material limits its application, and the TC of EP can be effectively improved by filling high TC fillers. In this paper, h-BN was modified using dopamine, so that abundant amino and hydroxyl reactive groups were introduced on the surface of h-BN, which were able to covalently bond with EP and optimize the interfacial bonding ability between <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{h}-\text{BN}$</tex> and EP matrix, and composites were also prepared by blending polycarbonate (PC) with EP and utilizing the low dielectric and high insulating properties of PC by the electrostatic spinning method. The surface chemistry and microstructure of the modified h-BN were probed by Fouriertransform infrared spectroscopy and scanning electron microscopy. The results showed that when the mass fraction of h-BN was 30 %, the maximum out-of-plane TC and in-plane TC were <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0.54 \mathrm{W} / \mathrm{m} \cdot \mathrm{K}$</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$1.19 \mathrm{W} / \mathrm{m} \cdot \mathrm{K}$</tex>, which were increased by 200 % and 98.3 %, respectively, and also possessed excellent insulating and dielectric properties, which provided a reliable preparation solution for the high TC epoxy potting compounds for drive motors.