Enhanced thermal conductivity of epoxy composites with hybrid carbon-based functional materials and nano-copper particles

In this paper, we doped nano-copper particles and carbon-based functional materials such as carbon fiber, scaly graphite and multi-walled carbon nanotubes (MWCNTs) into an epoxy in different proportions to investigate the impact of the heat transfer effectiveness on the epoxy. To enhance the heat transfer among the nano-copper particles, carbon-based functional materials are incorporated into a nano-copper/epoxy resin to form a hybrid composites respectively. The thermal conductivities of the prepared composite samples are calculated with a Netzsch LFA 447 laser flash apparatus and a differential scanning calorimeter. The experimental result shows that the thermal conductivity of nano-copper/epoxy composite and carbon-based functional materials/epoxy composite increased with the increasing nano-particles and carbon-based functional materials loading, for example, the thermal conductivity of the composites can amount to 6 times, 4.9 times, 6.8 times and 3 times that of the epoxy alone by adding 80 wt% nano-copper particles, 80 wt% carbon fiber, 30 wt% scaly graphite and 15 wt% MWCNT into an epoxy resin, respectively. The thermal conductivity of hybrid carbon-based functional materials/nano-copper/epoxy composite reaches the peak value that is 4.8 times, 6.1 times and 5.8 times that of the epoxy alone by adding 10 wt% carbon fiber, 15 wt% scaly graphite and 15 wt% MWCNTs into the matrix 40 wt% nano-copper/epoxy material, respectively. However, due to the increased carbon-based functional materials mass augments the viscosity of the polymer materials and leads to the agglomeration of these fillers, nano-particles and base materials, the composite presents a powdery structure, the deterioration of thermal conductivity of the composite is caused as the fillers for example the MWCNT content increases above 15 wt%. The SEM observations also illustrate the fact that increase in carbon-based functional materials mass augments the viscosity of the compound materials and the nano-tubes are agglomerated into large clumps of black powder.