Shape-stable hydrated salt based composite phase change materials with good flexibility, thermal reliability, and flame-retardant properties

Novel eutectic-MEG phase change material (PCM) was prepared by physical blend methods using sodium acetate trihydrate, glycine, disodium hydrogen phosphate dodecahydrate, and hydrophilic modified expanded graphite (MEG). The eutectic-MEG was introduced into silicone rubber to prepare the low-cost and shape-stable composite PCM (SSPCM). SEM analysis showed that the dispersion of the eutectic-MEG mixture was homogeneous in the SSPCMs. The flexibility of SSPCM improved with the increased amount of silicone rubber. Additionally, the thermal cycle and anti-leakage experiments suggested that SSPCM possessed good thermal reliability. SSPCM-55 showed an enthalpy value of 128.1 J/g, melting temperature of 48.36 °C, thermal conductivity of 0.81 W/(m·K), subcooling degree of 2.7 °C, only 2.7 % enthalpy loss after 100 heating and cooling cycles, and leakage rates of 2.65 %. The limiting oxygen index (LOI) values of all the SSPCMs were above 90 %, and they passed the UL-94 test with a V-0 rating. In addition, as the content of hydrated salts increased, the capacity of phase change thermal storage was significantly improved. This study provides beneficial ideas for the preparation of multifunctional PCMs in building energy conservation and thermal management of electronic products.