The effect of the reaction kinetics on the ionic conductivity for a comblike-type polyether (MEO) electrolyte with lithium bis(trifluoromethane sulfonyl)imide (LiTFSI) was characterized by DSC, complex impedance measurements, and H-1 pulse NMR spectroscopy. The ionic conductivity of these electrolytes was affected by the reaction condition of the methacrylate monomer and revealed by the glass transition temperature (T-g), spin-spin relaxation time (T-2), steric effects of the terminal groups, and the number of charge carriers indicated by the VTF kinetic parameter. In this system, the electrolytes prepared by the reaction heating rate of 10degreesC/min of MEO-H and 15degreesC/min of MEO-CH3 showed maximum ionic conductivity, sigma(i), two to three times higher in magnitude than that of the sigma(i) of the others at room temperature. As experimental results, the reaction kinetic rate affected the degree of conversion, the ionic conductivity, and the relaxation behaviors of polyether electrolytes. (C) 2003 Wiley Periodicals, Inc.