Thermally conductive phenol formaldehyde composites filled with carbon fillers

•Thermally conductive PF composites were prepared by compounding PF resin with carbon fillers.•Synergistic effect on thermal conductivity is achieved by replacing graphite with carbon fibers.•Carbon fibers provide higher thermal conductivity and better reinforcement than MWNTs.

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.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide