Chromatographic adsorption of polystyrene

The fractionation of polystyrene by adsorption column chromatography has been investigated at room temperature. The adsorbent used was activated carbon suspended on Celite. The experiments were carried out on mixtures of characterized polystyrene fractions using MEK (a poor solvent), toluene (a better solvent), and tetralin (a good solvent) as eluents. It was found that; (1) the better the solvent, the higher the molecular weight portion which can be eluted out; (2) the better the solvent, the greater the total amount of the polymer which can be recovered from the column; (3) the lower molecular weight homologs are eluted out before the higher molecular weight homologs; (4) by controlling certain factors, e.g., the moisture, the chromatograms obtained were satisfactorily reproducible in detail. By using successively MEK, toluene, and Tetralin, polystyrene can be fractionated in a single passage through a column with about 80% total recovery of the polymer on the column. Optimum fractionation in a single passage is obtained by eluting with appropriate mixtures of the above solvents in order of increasing solvent power of the mixture to the polymer. These results correlate with existing information on the adsorption of polystyrene from solution.