DIELECTRIC DISPERSION STUDIES OF POLYVINYL ACETATE IN TOLUENE

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Abstract
Dielectric measurements were performed on solutions of polyvinyl acetate in toluene at three fixed frequencies over a temperature range. Both the molecular weight of the samples and their concentration in solution were systematically varied. The experiments show that the dielectric behavior of polyvinyl acetate in solution is in better qualitative agreement with the Debye theory of dielectrics than that generally found for solid polymers. Nevertheless serious discrepancies appear when a quantitative comparison is made. It was found that only rough approximations of the molecular size can be made from the Debye theory. Activation energies and entropies for dipole rotation were calculated on the basis of the theory of absolute reaction rates. Small positive values of the entropy were found, indicating restricted dipole rotation. A relatively narrow distribution of relaxation times, approaching that commonly associated with nonpolymeric materials, was found.

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