PREPARATION AND PROPERTIES OF POLYMER SOLID ELECTROLYTES USING POLY(VINYL ALCOHOL) AND THERMALLY RESISTIVE POLY[ARYLENE(1,3-IMIDAZOLIDINE-2,4,5-TRIONE-1,3-DIYL)] AS MATRIX POLYMERS

Poly(vinyl alcohol) (PVA) and heat-resistive poly[arylene(1,3-imidazolidine-2,4,5-trione-1,3-diyl)] (poly(parabanic acid), PPA) with a T(g) of 350-degrees-C dissolve alkali metal salts such as Li [CF3SO3], LiBF4, LiClO4, and NaBF4 in high concentrations (1.0-1.5 g/g of the polymer). Complex impedance analysis of the polymer electrolytes thus obtained gives normal patterns usually observed for polymer electrolytes. The PVA-based polymer electrolytes have the electric conductivity (sigma) of 10(-5.5)-10(-3.5) S cm-1 at 20-degrees-C and at 1 g of Li salt/g of PVA, whereas the PPA-based polymer electrolytes exhibit the sigma value of 10(-7)-10(-5.5) S cm-1 under the same conditions. Temperature dependence of the sigma value obeys Arrhenius type equation for both types of polymer electrolytes; the activation energies are in the range 50-107 kJ mol-1. The PPA-lithium salt polymer electrolytes exhibit good heat resistance at 170-degrees-C and sigma value of about 10(-2) S cm-1 at 170-degrees-C. IR spectrum of the PVA-Li[CF3SO3] composite shows absorption bands originating from PVA and Li[CF3SO3] and no apparent shift of the nu(OH) band of PVA is observed. [(n-C4H9)4N]Y (Y = BF4, PF6) shows relatively low solubility in PVA (ca. 0.25 g/g of PVA). T(g) of PVA and PPA is lowered by making the composite with the lithium salt.