Enhanced Thermally Conductive Silicone Grease by Modified Boron Nitride

In this work, a chemical modification method was used to prepare silicone grease with high thermal conductivity. We report two preparation methods for thermal conductive fillers, which are hydroxylated boron nitride-grafted carboxylic silicone oil (h-BN-OH@CS) and amino boron nitride-grafted carboxylic silicone oil (h-BN-NH2@CS). When h-BN-OH@CS and h-BN-NH2@CS were filled with 30 wt% in the base grease, the thermal conductivity was 1.324 W m−1K−1and 0.982 W m−1K−1, which is 6.04 and 4.48 times that of the base grease (0.219 W m−1K−1), respectively. The interfacial thermal resistance is reduced from 11.699 °C W−1to 1.889 °C W−1and 2.514 °C W−1, respectively. Inorganic filler h-BN and organic filler carboxylic silicone oil were chemically grafted to improve the compatibility between h-BN and the base grease. The covalent bond between functionalized h-BN and carboxylic silicone oil is stronger than the van der Waals force, which can reduce the viscosity of the silicone grease.Keywords:silicone grease;boron nitride;thermal conductivity;interfacial thermal resistance;chemical modification