CROSSLINKING OF POLYVINYL 1-IMIDAZOLE IN SOLUTION INDUCED BY GAMMA-RADIATION

The radiation induced crosslinking of PVI was investigated in aqueous and methanolic solutions. Several samples of PVI were prepared by polymerization of the monomer in methanol and in CCl4 solutions and they were subjected to the crosslinking process. Gel doses were determined in solutions containing different amounts of polymer and the corresponding radiolytic yields of crosslinking were calculated. The relationships between sol fraction and dose on the one hand and gel dose and polymer concentration on the other were different from those observed earlier with solutions of PNVP irradiated under similar conditions. These results were explained by the reactivity of the double bonds in the imidazole groups. These double bonds may add small radicals generated by radiolysis of the solvent, thereby increasing the yield of polymeric radicals; they can also add polymeric radicals resulting in a higher yield of crosslinking. The polymers prepared from CCl4 solutions contain chlorine atoms. It was found that these polymers crosslink with much higher yields due to radiolytic sensitization. The swelling of the various gels in water was measured. These gels exhibit interesting complexing properties with respect to proteins and this effect may have applications in the pharmaceutical field. © 1990.