Design and preparation of novel shapeable PEG/SiO2/AA shape-stabilized phase change materials based on double-locked network with enhanced heat storage capacity for thermal energy regulation and storage

A facile method to prepare polyethylene glycol/silicon dioxide/acrylic acid shape-stabilized phase change materials (PEG/SiO2/AA SSPCMs) with various PEG mass fractions was developed by combining sol-gel method with in-situ polymerization. In PEG/SiO2/AA SSPCMs, PEG acted as the phase change materials and silica gel cross-linked with M served as the supporting materials. The prepared SSPCMs could be moulded with any shape and easily cutted into slices or powder, all shapes of which could remain solid without any leakage when the temperature went far beyond the melting point of PEG up to 120 degrees C. SEM results showed that the PEG/SiO2/AA SSPCMs exhibited the stable double-locked network by impregnating PEG into the cross-linked structure of silica gel and AA. Fourier transform infrared spectroscopy (FTIR) demonstrated there were not only physical adsorption but also cross-linked restrictions between PEG and the supporting materials. Thermogravimetric analysis (TGA) and thermal cyclic tests showed that PEG in the composites possessed an excellent thermal stability and reliability. Differential scanning calorimetry (DSC) measurement showed that the latent heat of the composites was higher than theoretical value and the increment percentage of the measured latent heat value to the theoretical one can even be as high as 49.5%. Moreover, PEG/SiO2/AA SSPCMs exhibited a good two-direction thermal regulation around a heat source, which has great potential for energy conservation and thermal regulation. (C) 2019 Elsevier B.V. All rights reserved.