Silicone-based alumina composites synthesized through in situ polymerization for high thermal conductivity and thermal stability

Silicone-based alumina composites for high thermal conductivity and thermal stability were fabricated through in situ polymerization, in which silanol groups were formed by a hydrolysis reaction with methyltriethoxysilane (MTES), dimethyldiethoxysilane (DMDES) and phenyltrimethoxysilane (PhTMS). Then, the silanol groups were polymerized in situ on the surface of alumina powders, which greatly improved the wettability and dispersity of the hybrid alumina powders in the matrix. When the hybrid alumina powder loading was 80 vol%, the silicone-based alumina composites presented a thermal conductivity of 2.92 W m−1 K−1, which was 15.3 times higher than that of the pure silicone resin. Furthermore, the silicone-based alumina composites showed a high thermal stability with a weight loss of less than 2.2% at 400 °C.