Preparation of Multifunctional Silicone Rubber Composites with Expanded Graphite-Encapsulated Phase Change Materials for Thermal Management

Organic phase change materials (PCMs), with their stable operating temperatures, high heat storage capabilities, and noncorrosive properties, hold significant potential for efficient heat storage and thermal management applications. However, their low thermal conductivity and leakage susceptibility severely restrict the practical applications of PCMs. Herein, we developed a phase change material and used it as a filler to prepare a phase change composite elastomer through integrating paraffin wax (PW) as the thermal storage material and expanded graphite (EG) as both thermal conductivity enhancer and structural support. Boron nitride (BN) in the composites serves dual functions: constructing a synergistic dual thermally conductive network with EG while ensuring electrical insulation. Then, the multifunctional elastomer composites filled with PCM led to good thermal conductivity of 1.18 W·m^–1·K^–1, energy storage density (14.58 J/g), and high electrical resistance of more than 10¹⁴ (Ω·cm). The network structure, as evidenced by characterization, achieves the effective encapsulation of PCMs within the elastomer matrix while maintaining structural integrity during phase transitions. This research offers an approach to creating multifunctional, thermally conductive thermal interface material with good heat storage and low thermal resistance.