The effect of hydrophilic modification of expanded graphite on the thermophysical properties of magnesium chloride hexahydrate

Magnesium chloride hexahydrate, as a phase change materials, is investigated usually to store solar energy. Here, the effect of hydrophilic modification of expanded graphite with Triton X-100 on the thermophysical properties of magnesium chloride hexahydrate was presented. Differential scanning calorimetry, scanning electron microscope, Fourier transform infrared spectroscopy and thermal gravimetric analysis, etc., were used. The magnesium chloride hexahydrate/hydrophilic expanded graphite composite phase change materials had more excellent thermal characteristics than magnesium chloride hexahydrate/expanded graphite composite phase change materials and pure magnesium chloride hexahydrate. The results showed that hydrophilic expanded graphite could better promote the endothermic and exothermic properties of magnesium chloride hexahydrate. After hydrophilic modification, the composites with higher melting enthalpy, better thermal conductivity and less supercooling were obtained. And the leakage test demonstrated that the hydrophilic modification of expanded graphite can reduce the leakage of magnesium chloride hexahydrate powerfully.