N-octanoic acid-based phase change composites synthesized by absorption polymerization for efficient thermal energy storage

Due to their high latent heat capacity near the phase change temperature, phase change materials (PCMs) have been extensively employed in passive thermal management and energy storage. Low thermal conductivity and leakage are, nevertheless, two ongoing limitations in PCMs thermal applications. In this work, a novel absorption polymerization process was carried out to prepare poly(methyl methacrylate)/expanded graphite/n-octanoic acid (PMMA/EG/OA) phase change composites (PCCs) having high thermal conductivity, enthalpy, encapsulation efficiency, as well as leakproofness. The PMMA/EG/OA PCCs are prepared in a two-step process: absorption of OA and methyl methacrylate (MMA) into the EG networks; and subsequent polymerization of MMA to cover the EG absorbed OA. The PCCs exhibit a latent heat capacity greater than 110 J/g, an encapsulation efficiency of approximately 100 %, and a thermal conductivity of 0.75-3.58 W/(m.K) at EG loadings of 6-15 wt%. Moreover, the PCCs display outstanding dynamical responsiveness and prolonged cycling reliability. Absorption polymerization is an efficient and profitable approach for producing high-performing PCCs that can be used for a variety of thermal-related areas, including thermal harvesting for renewable energy, building energy conservation, as well as thermal management of electrical devices.