POLYMER SWELLING .11. A MOLECULAR INTERPRETATION OF ASSOCIATION IN POLYSTYRENE LIQUID-SYSTEMS

The number (alpha(s)) of adsorbed molecules per phenyl group of polystyrene in solution (determined in this laboratory) was compared with the corresponding number (alpha-BAR) remaining after all of the excess non-adsorbed molecules were eliminated from the corresponding polystyrene-liquid (P-L) system (reported by Guenet). These correlations showed that, for P-L systems with the same polymer tacticity and the same class of liquids (based on similarity of molecular structure), alpha-BAR varies linearly with alpha(s). The fraction of solvated polymer that formed microdomains of associated polymer (owing to the change from alpha(s), to alpha-BAR) and the average number of monomer units in the solvated segments between these microdomains, which serve as quasi-crosslinkages, were estimated on the basis of the corresponding ratio of alpha-BAR to alpha(s). It was inferred from the results obtained that such microdomains of 'rigidized' polymer segments can evolve either via expulsion of already adsorbed solvent molecules or via incorporation of more solvent molecules to those already immobilized by adsorption.