Studies of GNS/paraffin composites on thermal properties and thermal conductivity

Thermal properties and thermal conductivity of paraffin wax reinforced with graphite nanosheet (GNS) were investigated. The GNS was prepared via a simple chemical method by stirring natural graphite flake in aqueous acid solution and subsequently subjected to heat treatment. Field emission scanning electron microscope (FESEM) was employed for morphological study. Thermal properties, including melting point, phase change temperature, and latent heat were tested using Differential Scanning Calorimeter (DSC), and thermal conductivity was measured using laser-flash analyzer (LFA). It is found that the thermal conductivity increases from 0.37 W/mK for pure paraffin to 4.59 W/mK when 5.0 wt% GNS were introduced into paraffin. The DSC results show that the first peak at 43.2 and the second one at 61.5 oC correspond to solid-solid and solid-liquid phase change, respectively. It is also found that the latent heat of GNS/paraffin composites decreases with increasing of GNS loading.