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Porous 4-Vinylpyridine-Divinylbenzene Copolymers– Varying Porosity in Different Bead Sizes of a Single Batch

Abstract Ion-exchangers, adsorbents, supported catalysts, etc, derived from porous copolymer beads are employed as medium in fine chemical separation processes. In these processes the exchange of reagents completes earlier in the smaller beads than in the larger beads in the same lot, which reduces the separation efficiency. So, it is potentially advantageous to preferentially introduce the macropores in the larger beads, as the macropores provide fast access to the reagents into the inner portions of the beads. In this study, camphor-a sublimable organic compound was employed as a diluent to create porosity in 4-vinylpyridinedivinylbenzene copolymer beads produced by o/w suspension polymerization technique. Camphor preferentially introduced macropores in the larger beads in the reaction. The results are explained on the basis of removal of diluent by sublimation phenomenon from the polymerizing droplets at a faster rate from the smaller beads as compared to the larger beads in the same batch.