Hydrodynamic and conformational properties of a phenyl-substituted para-aromatic polyester in dioxane and dichloroacetic acid☆

Intrinsic viscosity and translational diffusion (in two solvents: dioxane and dichloroacetic acid), as well as velocity sedimentation (in dioxane) were studied for 18 fractions and the original samples of phenyl-substituted poly-p-phenyleneterephthalate in the range of M = (2.9–86.3) × 103. On change from a non-polar to a polar solvent, the intrinsic viscosity (and consequently also molecular conformation) of the studied polymers remains unchanged. Nevertheless, an increase in characteristic diffusion (ηD/T) was observed for the high-molecular fractions. From the measurements in dioxane, the length of the Kuhn segment of the polymer molecules, A = (260 ± 40) A, and their hydrodynamic diameter, d = (15 ± 5) A, were determined.