Preparation and Characterization of Poly(ethylene glycol) Modified Cellulose Acetate Propionate and Its Application for Solid Polymer Electrolyte

Abstract

Cellulose acetate propionate was modified by esterification reaction with poly(ethylene glycol) using DCC/DMAP catalysts. The grafted poly(ethylene glycol) ratio in cellulose acetate propionate backbone were controlled by adjusting the amount of reactant. And the grafting yield could be quantitatively calculated using 1H nuclear magnetic resonance. As grafting yield increased, poly(ethylene glycol) interfered with the interaction between cellulose acetate propionate backbone, resulting in a decrease in the crystallinity and an increase in d-spacing value of cellulose acetate propionate. And due to the flexible poly(ethylene glycol) side-chain, glass transition temperature also decreased linearly with increasing grafting yield. Using the modified cellulose acetate propionate with different grafting yield, the homogeneous dimensionally-stable free-standing films used for solid polymer electrolyte were prepared. Compared with the glass transition temperature before the addition of Li cation, it increased when Li cation was added due to the interaction with poly(ethylene glycol) which could move the Li cation. As the grafting yield of the poly(ethylene glycol) conducting Li cation increased, the ionic conductivity of prepared films also increased.