A study of the effect of isomerism in a pendant radical on intramolecular interaction in polymers

Abstract

THE investigation of molecular interaction in condensed systems is one of the important tasks involved in the study of the structure of materials. One of the methods of investigating molecular interaction in both liquids and polymers is the s tudy of dielectric polarization and the determination of effective dipole moments. Determination of the dipole moment of a polar substance in a nonpolar solvent gives the magnitude/~0, the dipole moment of the molecule in isolation, which characterizes the structure of the compound in question. On the other hand the dipole moment calculated from experimental data on the basis of the statistical theory of polarization for liquids gives the value of the effective dipole moment, which is dependant both on /l 0 and a molecular interaction in the condensed system. In contrast to liquids, in a number of polymers when studied in solution at infinite dilution in a nonpolar solvent it has been found that the effective dipole moment per monomer unit differs from the dipole moment of the isolated molecule [1, 4]. This is associated with the fact tha t in the isolated polymer chain intramolecular interaction occurs between the separate monomer units, leading to correlation in the orientation of the polar groups. Thus in the case of polymers the value of the effective dipole moment of a single monomer unit in an isolated polymer chain is determined by the relationship