Thermal conductivity enhancement with different fillers for epoxy resin adhesives

• Thermal conductive adhesives with 8 different fillers were tested.
• The layer-shape filler is beneficial to form the heat pathways.
• The sharp-corner-shape filler is most difficult to achieve the heat pathways.
• The adhesive filled with the natural graphite has higher thermal conductivity.

Heat dissipation is an important issue for electronic devices. In the present work, we prepared eight kinds of thermal adhesives by filling the epoxy resin with natural graphite, copper, aluminum, zinc oxide, boron nitride, aluminum oxide, diamond and silver powders, and measured the thermal conductivity of all samples. The results show the eight fillers can efficiently improve the thermal conductivity of the epoxy resin. Meanwhile, we found the layer-shape filler is more favorable than the ball-shape filler and the sharp-corner-shape filler to enhance the thermal conductivity of epoxy resin, and the low price layer-shape natural graphite-epoxy adhesive had the highest thermal conductivity up to 1.68 W m−1 K−1 at weight 44.3% of the eight thermal adhesives. All the fillers and the cross sections of thermal adhesives morphologies images were characterized by scanning electron microscopy, and the thermal conductivities of all the samples were measured by Hot Disk TPS-2500 thermal constants analyzer.