High-performance epoxy resin/silica coated flake graphite composites for thermal conductivity and electrical insulation

Silica coated flake graphites as a thermally conductive and electrically insulating filler for epoxy resin composites were fabricated with surfactants and acid-base catalysis by a flexible sol-gel method. The volume resistivity of the silica coated graphite increased from 184 Omega m of the original graphite to 6391 Omega m because the silica coating provides an electrically insulating property. The influences of the silica coated graphite fraction, particle size and surface treatment on the performance of the hot-pressed composites were investigated. The thermal conductivity of the composites increased with incremental of the fillers concentration, as well as with decreasing of the filler size. The silica coated graphite/epoxy resin composites presented a high volume resistivity of 3.11 x 10(9) Omega m and thermal conductivity of 3.08 W m(-1) K-1 at 50 wt% filler loading ratio. The research sets the way toward the choice of a proper treatment for improving the thermal conductivity and electrical insulation of highly filled epoxy matrix composites.