Abstract
ABSTRACT Temperature-dependent dielectric relaxation studies of different viscosity grade Polyvinylpyrrolidones (PVP), PVP K-15, PVP K-30 and PVP K-90 having molecular weight 10,000 gmol−1, 40,000 gmol−1 and 360,000 gmol−1 respectively has been done in the frequency region 10 MHz to 50 GHz using Time domain reflectometry (TDR) technique. The frequency-dependent complex dielectric permittivity spectra have been explored by the Havriliak-Negami expression and is explained by the single relaxation model. The PVP molar concentration comprises the concentration domain of 0.0017 ≤ c/M ≤ 0.0176 for PVP-water system. The values of static dielectric constant (ε0), relaxation time (τ) and the empirical parameter (β) have been determined using non-linear least squares fit method along with the thermodynamic properties (activation enthalpy, entropy and free energy) of aqueous solutions of polymers.
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