Thermally Conductive and Electrically Insulated Silicone Rubber Composites Incorporated with Boron Nitride−Multilayer Graphene Hybrid Nanofiller

Thermally conductive and electrically insulating composites are important for the thermal management of new generation integrated and miniaturized electronic devices. A practical and eco-friendly electrostatic self-assembly method was developed to prepare boron nitride-multilayer graphene (BN-MG) hybrid nanosheets. Then, BN-MG was filled into silicone rubber (SR) to fabricate BN-MG/SR composites. Compared with MG/SR composites with the same filler loadings, BN-MG/SR composites exhibit dramatically enhanced electrical insulation properties while still maintaining excellent thermal conductivity. The BN-MG/SR with 10 wt.% filler loading shows a thermal conductivity of 0.69 W·m-1·K-1, which is 475% higher than that of SR (0.12 W·m-1·K-1) and only 9.2% lower than that of MG/SR (0.76 W·m-1·K-1). More importantly, owing to the electron blocking effect of BN, the electron transport among MG sheets is greatly decreased, thus contributing to the high-volume resistivity of 4 × 1011 Ω cm for BN-MG/SR (10 wt.%), which is fourorders higher than that of MG/SR (2 × 107 Ω·cm). The development of BN-MG/SR composites with synergetic properties of high thermal conductivity and satisfactory electrical insulation is supposed to be a promising candidate for practical application in the electronic packaging field.