Preparation and Characterization of Sodium Sulfate Decahydrate-Sodium Acetate Trihydrate Shape-Stabilized Phase ChangeMaterials

Inorganic hydrated salt phase change materials(PCMs) have the advantages of large latent heat, wide sourcerange, and no poison, and they are widely used in thefield ofbuilding energy conservation. In this study, sodium sulfatedecahydrate (SSD) and sodium acetate trihydrate (SAT) wereprepared into binary eutectic hydrated salt (EHS) by the meltblending method. The EHS was respectively impregnated intoporous adsorption materials, such as attapulgite and expandedperlite, to prepare two shape-stabilized phase change materials (SSPCMs) by the vacuum impregnation method. The chemicalstructure, crystal phase, and combination mode of eutectic salts and SSPCMs were determined by Fourier transform infraredspectroscopy and X-ray diffraction techniques. The results show that there is no chemical reaction between porous adsorptionmaterials and eutectic salt but a physical combination. Scanning electron microscopy results show that the eutectic is well-adsorbedin the porous structure of attapulgite or expanded perlite. Differential scanning calorimetry results show that, when the molar ratio ofSSD/SAT is 0.71:0.29, the phase transition temperature of EHS is 28.5 degrees C and the phase transition enthalpy is 128.1 J/g. Borax (1.5wt %) can effectively reduce the subcooling of binary EHS from 10.8 to 0.7 degrees C. Adding 25 wt % attapulgite can completely adsorbthe PCMs; the phase change enthalpy is 92.1 J/g; and after 200 cycles, the enthalpy decreases by 24.6%. Encapsulated bypolyurethane, the enthalpy value of SSPCMs only decreases by 10.4% after 200 thermal cycles, showing that the thermal stability issignificantly improved.