Bio-based Hydrogel Formed by Gamma Irradiation

Abstract

ARBOXYMETHYL chitosan (CMCt) was synthesized through ….. carboxymethylation reaction for chitosan. The prepared (CMCt) was subjected to crosslinking reaction by using γ-radiation. Different process parameters were investigated to clarify the effect of radiation dose, pH, and time upon the gel fraction and swelling properties of the produced hydrogels. The gel fraction was reduced after radiation dose 20 KG. The swelling% was dependent on the paste concentrations. At higher paste concentrations, 30-40% higher doses of γ-radiation, 20 KG, were required for optimum swelling. The high concentration paste, 40%, showed superior swelling in alkaline medium, pH > 8, while lower concentration paste manifested optimum swelling in neutral medium, pH = 7. The prepared (CMCt) hydrogels were characterized by FTIR, SEM, DSC and swelling kinetics.Keywords: Carboxymethyl chitosan (CMCt), Hydrogel, γ-ray radiation, Swelling, FTIR, SEM and DSC.Hydrogels are three-dimensional structure of cross-linked polymer, which have affinity for water absorption (1) . The hydrogel matrix has been hold by chemical or physical cross-linking that involves hydrophilic groups of homopolymers or copolymers (2) . Hydrogels swell in water by retaining a significant fraction of water within the pores structure without dissolving (3) . Several applications for hydrogels have been developed in biomedical and industrial fields such as artificial implants, contact lenses, enzyme immobilization (4)(5)(6) . Recent applications for hydrogels are interesting in drug delivery and agriculture in which water release from hydrogel is essential features (7)(8)(9)(10)(11)(12) . Radiation crosslinking is considered as clean and effective method for hydrogel preparation. On comparison with conventional hydrogel preparation, cross-linking through irradiation process did not need initiators, or chemical cross-linking. Radiation methods are efficient and safe alternative for cross-linking without using toxic additives (13) . Lugao reviewed the application of radiation processing in preparing hydrogels (14) . It was shown that the radiation technique is a powerful tool for controlling the degree of cross-linking of the produced hydrogels. Hydrogels, biodegradable and biocompatible polymers, obtained by irradiation cross-linking have a variety of applications, in different fields, such as biomedical devices (15) and control release of drug (16) .