Effects of Dopamine-Modified and Organic Intercalation on the Thermophysical Properties of Octadecane/Expanded Vermiculite Composite Phase Change Materials

For phase change materials (PCMs) confined in porous structure, the interface interaction between the PCM and the porous skeleton is the key factor to determine the thermal storage performance of PCM. In this study, the modified expanded vermiculite (EVM) was prepared by dopamine modification and DTA(+) intercalation method and a series of EVM-based composite phase change materials with form shape (fs-CPCMs) were prepared by physical impregnation using n-octadecane as PCMs. The heat storage performance of the composite phase change materials were improved obviously, and the encapsulation ratio is increased to 84.7% and 83.1%. The nonisothermal crystallization process of prepared composite phase change material were further studied. The effects of dopamine modification and organic intercalation on the encapsulation performance of EVM-based fs-CPCMs were analyzed. The results of XRD, FT-IR, thermal cycle, and TGA tests showed that EVM-based composite phase change materials had good chemical compatibility, thermal reliability, and thermal stability. This study provides a theoretical basis for the preparation of EVM-based fs-CPCMs with high thermal stability and good heat storage performance.