Polymer swelling. Part 21: Studies that correlate adsorptivity with molecular structure in crosslinked polystyrene systems saturated with sulfur-containing organic liquids

The adsorption parameter (α) for the members of five classes of sulfur-containing organic liquids were established in the usual way, and these data were compared to the results observed for the corresponding oxyethers in order to elucidate how the mode of adsorption to the pendent phenyl groups of the polymer at liquid-saturation affects the relative swelling power. The α-values for the thioethers are almost uniformly greater than those for the corresponding oxyethers. The aliphatic oxyethers (R′OR) adsorb unsymmetrically, i.e. the smaller, less complicated, group (R′) lies close to the adsorption site while the other (R) extends away from that site. In contrast, only the branched or multifunctional thioethers and the higher linear aliphatic thioethers are adsorbed in this mode. The lower linear aliphatic thioethers, the non-substituted cyclic thioethers, and the disulfides are adsorbed in the symmetrical mode, i.e. both substituents attached to the sulfur atom extend away from the adsorption site. The manner in which this changeover from one mode to the other affects the α-values in a given homologous series is discussed.