Preparation and performance analysis of low-temperature SiO2 aerogel-based phase change composites

Shape-stabilized SiO2 aerogel phase change composites (PCCs) was prepared by physical adsorption method with SiO2 aerogel as support material, and then used for secondary packaging.The optimal adsorption ratio of SiO2aerogel and phase change materials was explored, and microscopic morphology, chemical composition, pore structure, phase change characteristics, thermal reliability, shape stability and thermal insulation performance of composites were also characterized. The results show that the PCCs with 80%(mass fraction) phase change material (LS-80) has the optimization proportion, the composites exhibit shape-stability during the phase change process, and the melting point and melting enthalpy are -15.6 ℃ and 170.2 J/g respectively. The successful adsorption of SiO2 aerogel makes the specific surface area, pore size and pore volume of LS-80 reduced to 59 m2/g, 13 nm and 0.2 cm3/g. After 20 thermal cycles, the latent heat of packaged phase change material is decreased by 13.4%, while the SL-80 is only decreased by 2.8%, which proves good thermal reliability. Besides, the thermal conductivity of the composites is reduced and the thermal insulation capacity is enhanced due to the addition of SiO2 aerogel. The results provide experimental basis for the application of SiO2 aerogel PCCs in the field of cold chain logistics.