Research on Thermal Conductivity of Graphene-Paraffin Composite Phase Change Materials

Abstract

In this study, the thermal conductivity of paraffin matrix was improved by adding functional graphene. Composite phase change materials (PCMs) based on paraffin and acid-treated graphene were prepared and tested at various treatment temperatures (90, 120, and 150°C) with varying mass fractions of the filler. Preliminary acid treatment of graphene reduced the interfacial thermal resistance and improved the dispersion stability of the filler in the matrix due to the introduction of functional groups onto its surface. The following key characteristics were determined for the obtained samples: dispersion stability of graphene, micromorphological structure, and chemical compatibility of the components. Fourier-transform infrared spectroscopy results showed that graphene treated with acid at 120°C exhibited more pronounced absorption peaks, indicating a higher content of O–H, C=O, and C–O bonds compared to graphene treated at other temperatures. Thermal conductivity measurements of the composite PCM samples at various temperatures revealed that at 60°C, the maximum increase in thermal conductivity (23.2%) relative to pure paraffin was observed for the paraffin composite with 0.1 wt% acid-treated graphene (treated at 120°C). This confirms that the acid treatment temperature of 120°C is optimal. When the mass fraction of graphene in this composite was increased to 0.9%, the thermal conductivity reached 0.314 W/(m K), which is 49.55% higher than that of pure paraffin.