Thermally conductive phenol formaldehyde composites filled with carbon fillers

Abstract Thermally conductive phenol formaldehyde resin (PF)/graphite composites were prepared and the effects of a small amount of carbon fibers and multi-walled carbon nanotubes on the through-plane and in-plane conductivities of the composites were investigated. The use of graphite flakes increases the thermal conductivity of PF resin. The increase in in-plane thermal conductivity is much higher than that in through-plane thermal conductivity due to the layered structure of graphite. By replacing 10 wt% of graphite with carbon fibers, the through- and in-plane thermal conductivities of the PF composite are as high as 8.6 W/(mK) and 31.5 W/(mK), respectively. The partial replacement also improves the flexural properties of the composites.