DIELECTRIC ANALYSIS OF CELLULOSE AND ITS VINYLIC COPOLYMERS

The real and imaginary parts of the complex dielectric permittivity, epsilon' and epsilon", for some vinylic copolymers of cellulose [prepared with vinly acetate (VA) and methyl acrylate (MA) and Ce (IV) ions as initiator] and for cellulose were measured over a frequency band of 0.1-10(2) kHz and a temperature range from -40 to 100-degrees-C. In vinylic copolymers of cellulose, we observed one dielectric relaxation attributed to the alpha-relaxation of the vinylic side chain grafted on cellulose. In cellulose dielectric spectra, this relaxation did not appear, but we detected one relaxation that may correspond to the beta-relaxation. For these vinylic copolymers of cellulose, the epsilon" against epsilon' plot gives a skewed arc that closely resembles that of the Davidson-Cole model, with a broader distribution for high frequencies that shows the overlap of several relaxations in the process considered. Some differences observed between the vinylic copolymers of cellulose may be due to the composition and the length of the vinylic side chains and to the frequency of grafting on the cellulose.