Thermally conductive epoxy/boron nitride composites with high glass transition temperatures for thermal interface materials

Abstract

Thermally conductive polymer composites with high glass transition temperatures (Tg) are of interest for electronic devices in aerospace applications. Here, epoxy/boron nitride (BN) composites were fabricated using a highly heat-resistant epoxy as a polymer matrix and epoxysilane functionalized BN as thermally conductive filler. These composites exhibited excellent processability and high Tg of up to 275 °C. Moreover, the linear expansion coefficient (α) of the composite with a BN content of 30 wt% (48.89 × 10−6 °C−1) was 15% smaller than that of the pristine epoxy. The use of epoxysilane functionalized BN provided improved dispersibility in the epoxy matrix, thus reducing the interface thermal resistance and increasing the thermal conductivity. The thermal conductivity of the composite containing 30 wt% BN was 142% higher than that of the epoxy alone at 25 °C, and this excellent thermal conductivity was maintained at temperatures up to 150 °C. Furthermore, the single-lap shear strength at 150 °C reached 11.66 MPa. Notably, the prepared thermally conductive composite with outstanding thermal management characteristics exhibited excellent performance when used as a thermal interface material for electronic devices.