Polyurethane/n-octadecane@silicon dioxide-polyhydroxyethyl methacrylate form-stable phase change materials with enhanced mechanical properties and thermal energy storage

A kind of polyurethane rubber (PU)/n-octadecane (n-OD)@silicon dioxide (SiO 2 )-polymethyl acrylate (PHEMA) form-stable phase change material (PCM) was fabricated in this paper. n-OD@SiO 2 -PHEMA microcapsules were prepared in one-pot, through interfacial hydrolysis polycondensation of alkoxy silanes and radical polymerization of HEMA. Then, n-OD@SiO 2 -PHEMA microcapsules were added into PU matrix to obtain PU/n-OD@SiO 2 -PHEMA composites. SiO 2 -PHEMA hybrid shell not only provides a shelter for core material, but also increases interfacial bonding between microcapsules with PU and effectively improves the mechanical properties of composites. The morphologies, chemical compositions and crystal structures of microcapsules and composites were characterized by SEM, TEM, FT-IR and XRD methods. The thermal and mechanical properties of the microcapsules and composites were characterized by differential scanning calorimetry and mechanical performance tests. The results show that the thermal and mechanical properties of PU/n-OD@SiO 2 -PHEMA composites were better than those of neat PU. The PU/n-OD@SiO 2 -PHEMA composites endow the microcapsules with improved thermal reliability and leakage proof property. The composites were found as form-stable PCM with low leakage rate. The phase change latent heat of the PU/n-OD@SiO 2 -PHEMA composites was up to 85.1 J/g and the composites can be used for thermal energy storage.