Dielectric spectroscopy studies on (PVP plus PVA) polyblend film

The thermal behavior of (PVP + PVA) polyblend film have been examined using differential scanning calorimetry and scanning electron microscopy. Capacitance and loss tangent values of polyvinyl pyrrolidone (PVP) + polyvinyl alcohol (PVA) polyblend film were measured in the frequency range 1-100 kHz and temperature range 298-423 K. Dielectric permittivity of real part (epsilon ') was obtained from capacitance data and dielectric permittivity of imaginary part (epsilon '') was obtained from real part of dielectric permittivity and loss tangent values. The decrease in dielectric permittivity was observed with increasing frequency and also observed increase in dielectric permittivity with increasing temperature. The complex dielectric constant (epsilon*) has been described by the electric modulus M* = (1 /epsilon*) = M ' + iM ''. The data of M* has been analysed by the stretched exponential decay of the electric field, Phi(t) = exp-(t/tau(0))(beta). (c) 2005 Elsevier B.V. All rights reserved.