Preparation and Characterization of Paraffin@CLPS/MS Phase Change Microcapsules for Thermal Energy Storage

Abstract In this study, a series of encapsulated micro phase change material (EMPCM) based on industrial paraffin and inorganic‐organic hybrid shell was reported. The microcapsules (28#P@CLPS/MS) were synthesized with 28#paraffin (28#P) as phase change material (PCM), crosslinked polystyrene (CLPS) as flexible organic shell and modified nano SiO 2 (MS) as rigid inorganic shell, via a Pickering emulsion polymerization method. MS reduces the interfacial tension of water and plays a good emulsification effect. Secondly, after polymerization, the mechanical stability of the microcapsule shell can be enhanced, and the thermal reliability of the phase change microcapsules can be improved. The morphology, thermal energy storage capacity, and structure of microcapsules were characterized and analyzed. Besides, the grafting ratio of nano SiO 2 on the heat storage properties of microcapsules was investigated. When the graft ratio of nano‐SiO 2 was 4.2 %, the prepared microcapsules with highst paraffin content (54.37 %) and encapsulation efficiency (95.15 %). The synthesized microcapsules with regular spherical shape and size range of 1–5 μm, latent heat capacity (T m 28.20 °C, 86.35 J/g) and good thermal stability. Besides, the chemical composition of the microcapsules did not change after 500 cycles, and the latent heat did not decrease. Our research shows that Pickering emulsion polymerization is a convenient, economical and green method for the preparation of highly stable energy storage microcapsules.