A high-performance thermally conductive and electrically insulating silver@siloxane/graphene/epoxy composites at low filler content: Fabrication, mechanism study of insulation and thermal conductivity enhancement

Abstract

Polymer composites with electrical insulation and high thermal conductivity are in high demand in the electronics industry. The application potential of electronics material mainly depends on its mechanical properties. In this work, the silver nanoparticles (AgNPs) modified siloxane/graphene nanoplatelet core-shell hybrid (Ag@SiO/GNP) is synthesized through a two-step process. First, hydrolysis-condensation of TEOS and MPS is performed on the surface of pre-treated GNP. Subsequently, AgNPs are decorated on SiO/GNP core-shell hybrids to obtain Ag@SiO/GNP core-shell hybrid. The as-prepared hybrids serve as fillers of epoxy resin (EPR) to prepare Ag@SiO/GNP/EPR composite with high thermal conductivity (1.03W·m−1·K−1, which is 457.2% higher than pure EPR) and good electrical insulation (>1010Ω) at 1 wt% fillers loading. The hydrolysis-condensation of TEOS and saline coupling agent can decline the electrical conductivity of carbon-based materials efficiently, otherwise, the core-shell hybrids can be modified further based on the existing functional groups. The Ag@SiO/GNP/EPR composites exhibit excellent mechanical properties. The mechanism for thermal conductivity improvement of the composites prepared with these core-shell hybrids is demonstrated in detail.