Synthesis and properties of phase change microcapsule with SiO2-TiO2 hybrid shell

In this paper, SiO2-TiO2/paraffin phase change microcapsules with different contents of paraffin are prepared via sol-gel method. SiO2-TiO2 act as a shell and paraffin is used as a core. Scanning Electron Microscope (SEM), Laser particle size analyzer, Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffractometer (XRD), Differential Scanning Calorimeter (DSC) and Hot Disk are employed to characterize the morphology, chemical structure and thermal properties of SiO2-TiO2/paraffin microcapsules. The results show that there is no reaction between SiO2-TiO2 and paraffin. The average particle size is 11.38 μm when the encapsulation rate of paraffin is 39.8%. The latent heat and the phase change temperature of the SiO2-TiO2/paraffin microcapsule is 93.7 J/g and 29.0 °C, respectively. After 1000 times of heat storage-release cycles, the latent heat of the microcapsule was decreased by 6.58% and the encapsulation ratio was decreased by 2.62%. The thermal conductivity of the microcapsule is 11.63% higher than that of paraffin.