Liquid chromatography of polymer mixtures applying combination of exclusion and full adsorption/desorption mechanisms .3. Role of adsorption column and adsorbing eluent

Full adsorption/desorption plus size exclusion chromatography (FAD/SEC) is a useful procedure for the analysis and molecular characterization of complex polymer systems. The constituents of polymer mixture are selectively adsorbed and retained within a properly designed FAD column using an appropriate adsorption-promoting eluent. The retained polymers are then successively and selectively desorbed into an adjacent SEC column in which separation according to the size of macromolecules takes place, The FAD/SEC procedure was tested in model binary polymer mixtures of polystyrene plus poly(methyl methacrylate) and polystyrene plus poly(vinyl acetate). The role of both the FAD column size and the eluent applied for polymer adsorption was elucidated. It was shown that after the desorbing eluent was introduced, the zone of original adsorption-promoting eluent leaving the FAD column together with the desorbed polymer may affect the resulting SEC retention volumes, Therefore, it was necessary to optimize both above experimental parameters, chat is, FAD column size and the strength of adsorption-promoting eluent to obtain precise data on both molar mass and molar mass distribution of polymer constituents.