Untersuchungen zur Porosität und Polarität von hochquervernetzten PS/DVB-Copolymeren im Hinblick auf Eigenschaften in der RP-HPLC

In utilizing Ugelstad's activated swelling procedure monodisperse PS/DVB beads measuring about 5 µm in diameter were prepared for chromatographic use in packed columns. The variation of their porosity was achieved by altering the diluent and/or the crosslinker concentration. 10 different diluents, both solvent- and nonsolvent-types, were used in this case. Divinylbenzene was used as crosslinker having concentrations of 55, 80 or 100%. The variation of the beads polarity was achieved by incorporation of protected monomers, which exhibited compatibility with the seeded polymerization procedure. These protected monomers, e.g. p-acetoxystyrene, got hydrolyzed after polymerization yielding hydroxyl moieties. The size and morphology of these particles were examined by scanning electron microscopy. For the analysis of the internal porous structure inverse size exclusion chromatography was conducted. The chromatographic properties in reversed phase mode were analyzed by separation of homologous n-alkyl benzenes using an acetonitrile/water eluent. The results are showing a connection between the applied conditions during polymer synthesis, the observed sizes and porous properties and between the separation characteristics in reversed phase mode. This polymer beads library also provides the possibility for further optimization of this polymerization procedure regarding separation problems in RP-HPLC.