Irena Pulko, Peter Krajnc*
University of Maribor, Faculty of Chemistry and Chemical Engineering, Laboratory for Organic and Polymer Chemistry, Smetanova 17, 2000 Maribor, Slovenia E-mail: peter.krajnc@uni-mb.si 

Abstract
Sphere shaped polymer supports with styrene and 4-nitrophenylacrylate as monomers and divinylbenzene (DVB) or ethyleneglycoldimethacrylate (EGDMA) as crosslinkers were prepared by free radical polymerization in suspension medium. Ratio of monomers as well as the crosslinking degree varied in order to test the influences on bead size distribution, swelling and polymer network flexibility. The amount of crosslinker had an effect on bead size, average bead diameters being between 10 μm and 35 μm when 5% of crosslinker was applied and between 35 μm and 55 μm when 20% was used. The crosslinking degree also affected swelling in dichloromethane, water, methanol, toluene and acetonitrile, being more intense with lower concentrations of DVB or EGDMA. The flexibility of polymer network was investigated using reactions with 1,8-diaminooctane. High degrees of additional crosslinking was observed, namely between 58 and 95% indicating high flexibility of polymer network.

Key words: polymer supports, 4-nitrophenilacrylate, suspension polymerisation, bead size distribution