Constructing a highly vertically aligned network of h-BN/CF in silicone rubber composites: Achieving superior through-plane thermal conductivity and electrical insulation

Polymer composites with both high through-plane thermal conductivity (TC) and electrical insulation are desperately needed for the efficient thermal management of modern electronic devices. Herein, a highly vertically aligned network of hexagonal boron (h-BN) nitride/carbon fiber (CF) was constructed in silicone rubber composites via the combination of multistage stretching extrusion, layer-by-layer stacking and hot-pressing procedures. The composites exhibited superior through-plane TC and electrical insulation, simultaneously. The through-plane TC of the composites reached 9.5 W/(m·K) when the content of h-BN and CF was 120 phr and 5 phr, respectively. Meanwhile, the volume resistivity and breakdown voltage of the composites were 1.89 × 1013 Ω cm and 7.7 kV/mm, respectively, since the low content of CF was insufficient to form electrically conductive pathways. Furthermore, both simulation and experimental results indicated that the composites show outstanding heat dissipation performance. The composites with such hybrid networks are very promising for efficient heat dissipation in high-performance electronic devices.