Critical review of radiation processing of hydrogel and polysaccharide

Radiation processing of an aqueous solution of polymer initiated by OH radicals formed by radiolysis of water is applied for preparation of hydrogel wound dressing and plant growth promoter. Recently, Fenton reagent that generates OH radicals was successfully applied to synthesize PVP hydrogel. The Fenton reaction also can be applied to the depolymerization of chitosan. These progresses in the syntheses of hydrogel and oligo-chitosan by radiation and non-radiation methods such as hydrolysis, oxidative degradation, photolysis, sonolysis and degradation by microwave are reviewed to survey a possibility to reduce the costs of production. Radiation synthesized hydrogel should target value-added medical products because only radiation can crosslink and sterilize simultaneously. Oligo-chitosan can be produced economically by irradiation of solid chitin by Fenton reagent, if necessary.