The influence of the diluent system on the porous structure formation of copolymers based on 2-vinylpyridine and divinylbenzene. Diluent system: II-n-heptane/toluene

Anion-exchange resins based on 2-vinylpyridine (2VP) and divinylbenzene (DVB) were synthesized by suspension polymerization in the presence of a diluent mixture of n-heptane (HEP) and toluene (TOL) at different compositions. The effects of the composition of the diluent mixture and crosslinking degree (DVB content) on the porous properties of the resins were evaluated. It was found that the development of porosity was attained whenever the content of n-heptane in the diluent mixture was increased for all DVB contents employed. The resins were characterized by mercury porosimetry, BET surface area determination, and apparent density, swelling in methanol. The optical appearance and surface morphology of the copolymer beads were examined by optical and scanning electron microscopies (SEM), respectively.