Abstract
Samples of poly(N-vinylacetamide) were characterized by exclusion chromatography on silanized porous glass columns in DMF and DMF + 0.01M LiBr. Chromatograms obtained in pure DMF were very different in appearance from those observed using DMF + 0.01M LiBr. It is proposed that solutions of the polymer in the pure solvents form stable microcrystalline aggregates leading to the appearance of exclusion limit peaks for the higher MW samples. Strong ion-dipole interactions between the polymer and LiBr prevent the formation of such aggregates, resulting in more normal chromatographic behavior.