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

Thermally conductive polymer composites with high glass transition temperatures (T-g) 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 T-g of up to 275 degrees C. Moreover, the linear expansion coefficient (alpha) of the composite with a BN content of 30 wt% (48.89 x 10(-6) degrees C-1) was 15% smaller than that of the pristine epoxy. The use of epoxysilane functional-ized BN provided improved dispersibility in the epoxy matrix, thus reducing the interface thermal resis-tance 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 degrees C, and this excellent thermal conductivity was maintained at temperatures up to 150 degrees C. Furthermore, the single-lap shear strength at 150 degrees 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. (C) 2021 Published by Elsevier Ltd.