gamma-Ray Irradiation Practical Conditions for Low Molecular Weight Chitosan Material Production

摘要

The present work focuses on the y-ray irradiation doses and conditions(dry solid state,solid state dispersing in 0.5-2 % aqueous H_2O_2 solution,solid state dispersing in 1% aqueous acetic acid,and 2% aqueous K_2S_2O_8)to determine the level that the molecular weight of chitosan is lowered significantly without changing its primary structure.Molecular weight of chitosan(10~5-10~6 Dalton)is reduced approximately 50% under the gamma-ray dose of 20 kGy in the dry solid state.The decrease in molecular weight is enhanced up to 80% when chitosan is suspended in 0.5-2 % aqueous H_2O_2 solution during y-ray irradiation.In either condition,the backbone structure of the irradiated product is maintained with little change in the terminal chain.In the cases of(i)chitosan suspended in 2% aqueous K_2S_2O_8 and(ii)chitosan in 1% aqueous acetic acid,chitosans lose their primary structures and physical properties.