Epoxy/h-BN composites based on oriented boron nitride platelets with high thermally conductivity for electronic encapsulation

Owing to the miniaturization of power electronics and the development of portable and flexible devices, demands for highly thermally conductive, mechanically flexible, and electrically insulating composites have substantially increased. The high thermal conductivity of boron nitride (BN) platelets is expected to endow polymer composites with high thermal conductivity. Whilst BN is a typical two dimensional materials, which has anisotropic thermal conductivity. We have reported an remarkably increase in the in-plane thermal conductivity of the BN/epoxy composites through the fabrication of the horizontally aligned and densely packed BN in the epoxy matrix via a vacuum-assisted self-assembly technique. In addition, we compared the influence of the different BN particle sizes on the thermal conductivity of the composites. In this study, the range of BN particles sizes used are 5-8 μm, 15-20 μm and 25-30μm, respectively. The results indicated that the BN with lager size in matrix renders the composites high thermal conductivity at same content. The larger BN platelets can more easily form conductive chains of filler compared to the smaller filler particles. Meanwhile, the smaller filler particle can more easily scatter phonons suppressing heat transfer. It is clear that epoxy with aligned BN platelets has great promising for high thermal conductive insulating materials for the power microelectronics integrated in packaging.