Abstract: A comb polymer(CP350) with oligo-oxyethylene side chains of the type-(CH₂ CH₂O)₇CH₃ was prepared from methyl vinyl ether/maleic anhydride copolymer and poly(ethylene glycol) methyl ether.The polymer can dissolve LiNO₃ salt to form homogeneous amorphous polymer electrolyte.This electrolyte system was first found to have two class glass transitions,and the two T_gs were observed to increase with increasing salt content.The ionic conduction was measured by using the complex impedance method,and conductivities were investigated as functions of temperature and salt concentration.At 25℃,the ionic conductivity maximum of this system can get to 3.72×10^-5S/cm at the [Li]/[EO] ratio of 0.057.The appearance of the conductivity maximum has been interpreted as being due to the effect of T_g and the so called physical crosslinks.The temperature dependence of the ionic conductivity displaying non-Arrhenius behaviour can be analyzed using the Vogel-Tammann-Fulcher equation and interpreted on the basis of the configurational entropy model.

Key words: Solid polymer electrolytes, Complex impedance spectrum, Two class glass transition, VTF behaviour