POLYMER ELECTROLYTES BASED ON POLYESTERS OF THIODIPROPIONIC ACID .1. SYNTHESIS, CHARACTERIZATION AND IONIC-CONDUCTIVITY MEASUREMENTS

A series of aliphatic polyesters of 3,3'-thiodipropionic acid and line ar glycols containing a different number of ethylene oxide groups has been prepared and characterized. These polymers show low values of gla ss transition temperature and appear, at room temperature, as highly v iscous liquids, in which LiClO4 can be dissolved easily. The resulting transparent semi-solid solutions behave as polymer electrolytes with high ionic conductivity, which has been investigated as a function of LiClO4 concentration, temperature and chemical structure, i.e. the num ber of thioether sulfur and ether oxygen atoms in the backbone. The ma in factors that affect conductivity are the glass transition temperatu re and the solvating capacity for the lithium ions. It was found that both the oxygen and sulfur atoms contribute to solvating lithium ions.