Enhancing thermal conductivity of silicone rubber via constructing hybrid spherical boron nitride thermal network

In this work, a series of spherical boron nitride/silicone rubber (sBN/SR) composites were prepared, and the influence of different shapes and sizes of BN on the thermal conductivities of the composites was investigated. Additionally, hybrid spherical boron nitride/silicon rubber (hybrid sBN/SR) composites were fabricated by synchronously incorporating two kinds of sBN particles into SR to perfect the thermal conduction paths, and a synergistic effect of the fillers was achieved. The thermal conductivity of the composite could reach 1.70 W/(m·K) at the 35 wt% filler content, which is clearly superior to the composite containing single type of filler and stands at a very high level at such a filler fraction according to the reported literature. Also, the experimental results were supported by the Agari's equation. In addition, the composites show a low hardness (shore A hardness < 60) due to the low filling content. The prepared materials hold great promise in thermal interface materials for thermal management of state-of-the-art electronic equipment.