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SynopsisPorous polymers were prepared by suspension copolymerization of styrene/divinylbenzene in various ratios together with various quantities of diluents, both solvating and nonsolvating. Parallel bulk polymerizations were made to detect the onset of gelation and phase separation. The dry polymeric beads were examined by a range of techniques: apparent densities; mercury porosimetry; nitrogen sorption/desorption isotherms, vapor sorption, equilibrium swelling, and electron microscopy. The properties of the porous polymers are discussed in tkrms of phase separation during polymerization consequent on either an unfavorable polymer-solvent interaction or a microsyneresis.

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The adsorption behavior on silica of some polystrenes of moderate molecular weight distribution, both singly and in mixtures, has been examined. The adsorption isotherms indicate that, in both a good solvent (trichloroethylene) and under theta conditions, the species of higher molecular weight is preferentially adsorbed at or near full surface coverage, but that the smaller adsorbate has an improved opportunity for adsorption at low surface coverage. The use of tritiated adsorbates substantiate the isotherm data in cyclohexane solution.