Significantly improved thermal conductivity of silicone rubber and aligned boron nitride composites by a novel roll-cutting processing method

Abstract Composites of silicone rubber (MVQ) incorporated with aligned boron nitride (ABN) were prepared by two different processing methods, namely the stacking-cutting and roll-cutting methods, and compared with the pure MVQ and MVQ/unaligned BN composites that were prepared by mechanical mixing. The effect of the content and average diameter of BN on the thermal conductivity of the MVQ/ABN and MVQ/BN composites was investigated, and the accompanying mechanism was revealed. The results showed that the thermal conductivity of the composites increased with increasing BN content. The thermal conductivity of the MVQ/ABN composites was significantly improved in comparison with that of the MVQ/BN composites because the aligned BN can construct more efficient thermal conductive pathways than the unaligned BN. The BN composite sample with an average diameter of 30 μm exhibited higher thermal conductivity than that with an average diameter of 10 μm. Furthermore, the thermal conductivity of the MVQ/ABN composites prepared by the roll-cutting method was higher than that prepared by the stacking-cutting method. A maximum thermal conductivity of 6.3 W/(m·K), which was 5.5 time that of the MVQ/BN composites, was achieved when the BN content was 250 phr and its average diameter was 30 μm.