Thermal characterizations of the graphite nanosheets reinforced paraffin phase-change composites

Two paraffin composites filled separately with randomly distributed graphite nanosheets (R-GNs) and oriented graphite nanosheets (O-GNs) were fabricated, and their thermal properties and structural characteristics were investigated. The experimental results show that a conductive network at 1.0 wt.% graphite nanosheet (GN) loading was found. The thermal conductivities of the R-GNs/paraffin and the O-GNs/paraffin composites are 4.47 ± 0.15 and 1.68 ± 0.07 W/m K, respectively, when 5.0 wt.% GNs were introduced. The Maxwell–Euken model and the modified rule of mixtures model were proposed to predict the thermal conductivities of the R-GNs/paraffin and the O-GNs/paraffin composites, respectively. The melting point and the solid–liquid phase transition temperature of the R-GNs/paraffin composites are approximately 53 and 60 °C, respectively, and neither of these values was significantly affected by the presence of GNs. Decreases in the latent heat of the R-GNs/paraffin composites with increased GN loading were also found.