Dielectric method of studying the molecular movement in polydivinylacetals

Abstract

T~E dielectric properties of the polyvlnylacetals prepared by the acetylatmn of polyvmyl alcohol have been stuched m a number of works [1-4] Besides acetal rmgs, the maeromolecules of these polymers also contained a considerable number of umts which carry hydroxyl groups. By forming hydrogen bonds they exert a considerable influence on the kinetic properties of the macromolecule and its segments, increasing the relaxation time of segments and kinetic groups. For this reason we decided to study the polyacetals prepared by the cyclic polymerization of the corresponding monomers of dlvmylacetal, from winch the OH group is absent. The study of the dielectric properties of these polymers [5] showed that the reason for dipole relaxation, particularly the dipole-group process, is the movement of the polar kinetic unit containing the ether oxygen of the side rings [5] The immediate proximity of the polar bonds of the oxygen atoms to the main carbon chain raises the question of the participatmn of the main chain in the process of dipole-group relaxation. The answer can be found by studying the influence of certain factors on the dipole-group loss parameters, the effects of plasticizing low-molecular weight materials on the relaxation time of a given kind of loss for instance Besides this, in view of the ring structure of the maeromoleeule it is interesting to assess the spread of dipole-segmental and chpole-group loss relaxatlon times, and the effective dipole moments of a chain mono-unit.