DYNAMO-OPTICAL AND ELECTRO-OPTICAL PROPERTIES OF SOLUTIONS OF DIPHENYL-SUBSTITUTED POLY-P-PHENYLENETEREPHTHALATE IN POLAR AND NONPOLAR SOLVENTS

Abstract Flow and electric birefringence have been investigated for solutions of a number of fractions of a para -aromatic polyester using dioxane and dichloroacetic acid as solvents. It was found that, on passing from a nonpolar (dioxane) to a polar solvent, the optical and hydrodynamic properties of the chain do not alter whereas electro-optical characteristics undergo drastic changes. It was shown that in dioxane the hydrodynamic and dynamo-optical characteristics of the polyester under investigation correspond to those of a rigid-chain polymer, whereas the electro-optical correspond to those of a flexible-chain polymer. This unique combination of properties is due to the specific features of the dipole structure of the monomer unit and a considerable difference in the longitudinal and transverse dipole rigidities of the chain of this polyester.