Abstract:

To address the issue of poor stability in practical applications and expand the application range of inorganic hydrated salt phase change materials for low-and medium-temperature thermal energy storage, we designed a composite phase change material by coating a dual-network hydrogel composed of polyacrylamide and sodium alginate with Na₂SO₄·10H₂O (sodium sulfate decahydrate, SSD). The resulting inorganic hydrated salt composite phase change material exhibited a phase change temperature range of 30—45 ℃. The microstructure, chemical composition, crystal structure, and thermophysical properties of the phase change hydrogels were characterized using SEM, FT-IR, XRD, and DSC. The results demonstrated the successful encapsulation of SSD within the dual-network hydrogel, forming a composite phase change hydrogel with high thermal conductivity, shape stability, and excellent temperature control properties. At an SSD mass fraction of 70%, the melting enthalpy reached 123.91 J/g for the phase change hydrogel. After 500 thermal cycles, he latent heat of phase change and temperature remained stable for the phase change hydrogel, indicating good thermal cycle stability. This study effectively addressed concerns regarding the poor stability of inorganic hydrated salt-based phase change materials while providing new insights and theoretical data support for future applications in low- to medium-temperature thermal energy storage.

Key words: sodium sulfate decahydrate, dual-network hydrogels, phase change material, thermal properties