Estimation of Solubility Parameters from Refractive Index Data

THE solubility parameter, δ , of a polymer or compound is a measure of intermolecular forces and is useful for the studies of many polymer characteristics, particularly glass transition temperatures 1 , solubilities and diffusion or transport properties. 2 It is therefore highly desirable to have a convenient method for quickly estimating δ values of polymers. It was suggested by Hildebrand and Scott, and later by Scatchard, that solubility parameters could be calculated from optical data such as refractive index measurements 3,4 . In this article we report some semiempirical correlations between solubility parameters and refractive indices for a series of model compounds and polymers. This work refers only to hydrocarbon and other organic materials; further work would be required to determine if an extension to inorganic polymers is possible.