Synthesis and characterization of cellulose-g-polyoxyethylene (2) hexadecyl ether solid–solid phase change materials

A series of novel solid–solid phase change materials, namely, cellulose-g-polyoxyethylene (2) hexadecyl ether (Cellulose-g-E2C16) copolymers, were synthesized using toluene 2,4-diisocyanate (TDI) as a coupling reagent in the ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl). The optimum prepolymerization conditions were determined to be 25 °C and 75 min without catalyst, and the optimum reaction conditions of the grafting step were 90 °C, 6 h and 0.1 wt% dibutyltin dilaurate (DBTDL, weight percent of TDI). The successful grafting was confirmed by FTIR and 1H-NMR. The properties of the Cellulose-g-E2C16 copolymers were investigated by DSC, TG and XRD. It is shown that the heat storage ability and phase change temperature of Cellulose-g-E2C16 copolymers depended on the degree of substitution. The crystalline type of the grafted E2C16 was not affected by the cellulosic backbone. Compared with E2C16, Cellulose-g-E2C16 copolymers showed better thermal stability. They are expected to be widely applied in the area of thermal energy storage.