Abstract
We have found that diffusion of polystyrene into the micropores of packed porous chromatographic columns of a type used for size separations of macromolecules is strongly influenced by the flow rate of the polymer solution through the column and also by the macromolecular size and internal pore size of the column packing. Dilute polymer solutions (0.05 wt.% polystyrene in THF) were pumped continously through the columns (Dupont SEC). Step changes in flow rate were made and the polymer concentration in the column effluent was monitored continuously. When the flow rate was increased, the partition coefficient for polymer between mobile and stationary phase shifted toward more polymer retention in the column, as evidenced by the drop in outlet concentration for several minutes following the step change. Molecular weight, pore size and solvent effects have all been thoroughly investigated. The conclusion is that polymer molecules diffuse into the internal pores of the column packing at a flow ratedependent rate and moreover, they do so to a greater extent the larger the polymer molecule, provided they are not sterically excluded from the pores. This dynamic diffusional partitioning is clearly important in its effect on resolution characteristics of an SEC column and also sheds some light on qualitatively similar observations in polymer flooding for enhanced oil recovery.
Original language | English (US) |
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Pages (from-to) | 452-461 |
Number of pages | 10 |
Journal | Rheologica Acta |
Volume | 19 |
Issue number | 4 |
DOIs | |
State | Published - Jul 1980 |
Externally published | Yes |