Hybrid Filler with Nanoparticles Grown in Situ on the Surface for the Modification of Thermal Conductive and Insulating Silicone Rubber

Insulating materials with high thermal conductivity have become the key to solving the internal heat problem of electronic components. In this study, two fillers were prepared by the in situ generation method. The uniform distribution of silicon dioxide (SiO2) nanoparticles and silver (Ag) nanoparticles on the surface of graphene oxide (GO) and silicon carbide (SiC) was proved by characterization methods such as micromorphology (TEM and SEM) and elemental analysis (XPS), respectively. The fillers above prepared were then added to silicone rubber (SR) to improve its thermal conductivity. SiO2 nanoparticles attached to the GO surface were compatible with the SR matrix, so the thermal resistance of the interface between the GO and the matrix was reduced. The thermal conductivity of Ag nanoparticles generated on the SiC surface was significantly better than that of SiC whiskers. Besides, the composite filler was more conducive to the formation of a heat conduction path, so the thermal conductivity of silicone rubber was improved. In addition, the composite SR maintained pleasing electrical insulating properties, and the volume resistivity of all samples was above 1013 Ω·cm. The prepared composite filler and composite SR provide ideas for developing high-performance thermally conductive and insulating polymers.