6533b7d4fe1ef96bd12633b1

RESEARCH PRODUCT

A Qualitative Analysis of Secondary Mechanisms in SEC of Polymers Through the Mean Value of the Viscosimetric Exponent

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Abstract Size exclusion chromatography (SEC) universal calibration curves for poly(dimethylsiloxane), polybutadiene and poly(2-vinylpyridine) samples have been obtained in columns packed with cross-linked polystyrene gel using cyclohexane, toluene, benzene, dioxane and tetrahydrofuran as eluents at 25°C. The eluents exhibit different thermodynamic quality for the polymeric solutes and for the gel matrix which is reflected in the values of their Mark-Houwink-Sakurada exponents a. The plots of log(hydrodynamic volume) versus retention volume for the polymeric solutes in different eluents are displaced to higher retention volumes than that of THF-polybutadiene (ideal SEC), evidencing the existence of secondary mechanisms. This elution behavior could be qualitatively explained through the mean average value ā, but a quantitative analysis requires the knowledge of solute—solvent, solvent—gel, solute—gel and ternary interaction parameters.