Abstract: Shape-stabilized phase change materials (PCMs) were prepared by incorporation of capric-palmitic acid (CA-PA) eutectic mixtures within the expanded perlite (EP) via vacuum impregnation.The chemical stability,microstructure,thermal properties and thermal stability of PCMs were characterized by Fourier transform infrared spectroscopy,scanning electron microscopy,differential scanning microscopy and thermogravimetry.The results indicated that CA-PA was impregnated into EP by physical attraction.The optimal mass fraction of CA-PA adsorbed on EP was 55%,and the latent heats of fusion and solidification were 81.5 J/g and 79.7 J/g,respectively,with the corresponding melting and solidification temperatures of 27.9℃ and 19.1℃.The thermal properties of PCMs kept almost unchanged after 1 000 melting-freezing cycles.