DIELECTRIC-RELAXATION AND ELECTRIC MODULUS BEHAVIOR IN POLY(VINYL ALCOHOL)-BASED COMPOSITE SYSTEMS

The ultraviolet spectra of pure and lead salt-poly(vinyl alcohol) (PVA ) composite films were studied at room temperature. Blending of PVA wi th lead acetate and lead nitrate cause a considerable change in the UV spectrum, indicating electronic structure modifications. The complex permittivity (epsilon) and the complex electric modulus (M*) of the p ure PVA and the PVA-based composite films were investigated between 30 0 and 400 K in the 100 Hz-100 kHz frequency range. The frequency depen dence of the permittivity is influenced by the space-charge polarizati on. The interfacial polarization is manifested at high temperature and becomes important only above the PVA glass transition temperature and below 1 kHz. Dielectric properties of PVA-lead nitrate composite reve aled that the salt is complexed with PVA through hydrogen bonding. (C) 199G John Wiley & Sons, Inc.