Phase Change Composites Based on Double-Shell Microcapsules with High Latent Heat and Low Leakage Rate for Thermal Energy Storage and Temperature Regulation

A series of novel paraffin (Pn)@polymethyl methacrylate (PMMA)@silicon dioxide (SiO2) double-shell phase change microcapsules (Pn@PMMA@SiO2) were designed by interfacial polycondensation and radical polymerization, and then Pn@PMMA@SiO2 were embedded in high density polyethylene (HDPE) to fabricate HDPE/Pn@PMMA@SiO2 phase change composites (PCCs) by melt blending. The effect of PMMA contents on Pn@PMMA@SiO2 and Pn@PMMA@SiO2 contents on PCCs were investigated, respectively. Thermal and anti -permeable properties of Pn@PMMA@SiO2 and PCCs were characterized by differential scanning calorimetry (DSC) and leakage rate tests. The results showed that the enthalpy and leakage rate of Pn@PMMA@SiO2 with 10 wt% PMMA were 156.6 J/g and 1.85 %, which displayed outstanding latent heat storage/release capability and good anti-permeable property. And the PCCs with 40 wt% Pn@PMMA@SiO2 displayed dependable thermal energy storage capability as well, which could reach to 52.7 J/g. In addition, the tensile strength of PCCs-40 could be up to 19.9 MPa, and the density of PCCs was decreased with introduction of Pn@PMMA@SiO2. Hence, the new kind of PCCs can be used for thermal management and temperature regulation for lightweight building materials.