POLYMER-BASED PACKING MATERIALS FOR REVERSED-PHASE LIQUID-CHROMATOGRAPHY - STERIC SELECTIVITY OF POLYMER GELS PROVIDED BY DILUENTS AND CROSS-LINKING AGENTS IN SUSPENSION POLYMERIZATION

The effects of Preparation conditions on the pore structures and chromatographic properties of porous polymer gels were studied. The diluents in suspension copolymerization of methyl methacrylate with a divinyl monomer affected the size and volume of micropores as well as those of the macropores. The use of a non-solvent to the polymer such as alkanes and n-alkyl alcohols resulted in polymer gels with micropores of smaller size and volume, accompanied by large macropores. Preferential retention of rigid, compact solutes was observed with such polymer gels due to the size-exclusion effect of the micropores. In contrast, better solvation of the polymer with cyclohexanol during polymerization resulted in gels with micropores of larger size and volume, leading to the preferential retention of bulky molecules, while producing macropores of smaller size and volume. Preferential retention of rigid, compact solutes was also observed with gels with higher cross-linking density.