▎ 摘　　要

A simple approach is developed to obtain a multiscale network of heat conducting by filling spherical alumina (S-Al2O3) and graphene nanoplatelets (GnPs) into silicone rubber (SR). This unique structure effectively minimizes the thermal contact resistance between fillers and matrix. The physical properties of the composites are characterized by thermal conductivity, density, and tensile strength. A high thermal conductivity of 3.37 Wm(-1) K-1 has been achieved, which is 47.1% higher than the single filler at the same loading. A strong and obvious synergistic effect has been observed as S-Al2O3 and GnPs filled into silicone rubber matrix. It is interesting that the composites with GnPs have the lower density (2.62 g/cm(3), reduced by 6%) and the superior tensile performance, compared to silicone rubber composite with neat S-Al2O3. The composites have the potential applications in heat dissipation of light-emitting diode.