Preparation and characterization of expanded perlite/paraffin composite as form-stable phase change material

•EP/PA composite has melting temperature 27.56°C and latent heat 80.9J/g.•EP/PA composite containing paraffin as 60wt.% shows the best thermal properties without any liquid leakage problem.•The melting temperature and latent heat of the EP/PA composite does not change after repeated thermal cycling.•The homogeneous EP/PA composite can be obtained by the direct incorporation method. In this study, a form-stable expanded perlite/paraffin (EP/PA) composite was prepared by absorbing paraffin into porous networks of expanded perlite. The form-stable composite was characterized by using Differential scanning calorimetry (DSC), Thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscope (SEM) techniques and leakage test. The melting temperature and latent heat of the form-stable EP/PA composite containing 60wt.% paraffin were determined as 27.56°C and 80.9J/g, which showed good thermal energy storage property, thermal stability and thermal reliability. In addition, the FT-IR results revealed that there was no chemical interaction between the expanded perlite and the paraffin. By means of the direct impregnation method, the paraffin was distributed uniformly in the EP/PA composite without liquid leakage. All the results suggested that the form-stable EP/PA composite has great potential in building applications for thermal energy storage.