Improvement of thermal, electrical and mechanical properties of composites using a synergistic network of length controlled-CNTs and graphene nanoplatelets

Improving the utilization of industrial thermal waste and abundant solar thermal energy is of immense significance in energy management and thermal engineering. Latent heat thermal storage is one of the emerging methods that employ the large caloric density of materials mainly as a result of its constant-temperature phase-change process. Herein, paraffin was selected as the phase-change matrix which was reinforced with length controlled-carbon nanotubes (LCCNTs) as the primary filler and graphene nanoplatelets (GNPs) as the secondary reinforcing nanoparticles. Electrical conductivity (EC) of samples was tested, and carbon nanotube (CNT) was proved to be more effective in the increase of EC, than GNP. Furthermore, the thermal conductivity of the fabricated composite phase-change material was measured, and at the filler ratio of 5 phr an enhancement of about 148.0% was found compared with that of pristine paraffin. Optimal CNT/GNP ratios were also determined at the maximum enhancement achieved for each property. To observe the effect of LCCNTs on the mechanical properties of composites, polyester resin-based composites were prepared, and the tensile strength results are reported.