▎ 摘　　要

The use of hybrid filler is a promising strategy for development of thermally conductive polymer composites. This paper reported the measurement of thermal conductivity of the epoxy composite filled with a hybrid filler of graphene nanoplatelet (GNP) and silicon carbide (SiC) microparticles. For this hybrid filler, the effect of the average size of SiC on composite thermal conductivity was examined. The results showed that the thermal synergistic effect was highly affected by the average size of the SiC. By using a hybrid filler of 11% vol. GNP and 9% vol. 1 mu m-size SiC micro-particles thermal conductivity has reached 3.44 W m-1 K-1. This value is 42% higher than the thermal conductivity of pure GNP composite at the same total filler loading. Moreover, additional experimental and theoretical analyses were performed to more explicitly understand the mechanism of thermal synergistic effect. It was shown that the synergistic effect between GNP and SiC is attributed to the more effective formation of thermally conductive pathways through the composite. Our results elucidate the mechanism of the thermal synergistic effect and providing information on hybrid filler design to achieve further improvement in the thermal conductivity of polymer composites.