CONCENTRATION-DEPENDENCE OF ELUTION VOLUMES IN SIZE EXCLUSION CHROMATOGRAPHY OF POLYMER-MOLECULES .2. POLY(METHYL METHACRYLATE) IN IDEAL SOLVENT

The concentration effects occurring in size exclusion chromatography of polymer molecules were investigated for the case of elution of macromolecules in an ideal solvent. Increases in the elution volumes with polymer concentration evidently are detectable with the high efficiency columns employed. The concentration dependence of elution volumes is much lower than that previously determined with good solvents. The main factor contributing to the shift of elution volumes seems to be the viscosity of the polymer solutions, but another effect appears also to be present. In semiconcentrated solutions of polymer molecules in ideal solvents a continuous contraction of the polymer chains apparently occurs, below their unperturbed dimensions, similar to that happening when the temperature of ideal solutions is decreased. More investigation on this point is needed.