Viscosity of dilute and moderately concentrated polymer solutions

Abstract

An equation suggested by Fedors for application to intrinsic viscosity determination of dilute to moderately concentrated solutions is re-examined taking into account polymer swelling behaviour and polymer-solvent interactions. For a given polymer-solvent system, the observed variation of the constant of the equation (defined as the maximum volume fraction to which polymer particles can pack), øm and its estimated values beyond its theoretical limit of unity are the main difficulties in its application. These problems are solved by a suggested modification to the equation, and øm is shown to be less than or equal to unity and constant for many polymer-solvent systems. This modification facilitates the use of the Fedors equation for dilute to concentrated polymer solutions for determining the intrinsic viscosity at a single polymer concentration. © 1993.