Hydrogels are 3-D crosslinked hydrophilic polymer networks that absorb large amounts of water up to hundred or thousand times of its dead weight without dissolving. Hydrogels can be prepared starting from hydrophilic monomers, prepolymers or existing hydrophilic polymers. They can be prepared by two methods: chemical and irradiation. Gamma Radiation can be used as a initiator and a cross linker. Graft copolymerization of hydrophilic monomers and polyfunctional comonomers, leads to the formation of hydrophilic network structures. Cross-linking during polymerization is an important factor that yields a network polymer, which will not dissolve in water, and can absorb and retain water under low load. In the present study, hydrophilic hydrogels based on poly (2-)Dimethyl)amino ethyl methacrylate( as synthetic monomer and sodium alginates as natural polymer (AG) were prepared by gamma irradiation. Excellent water absorption and water retention abilities was shown by the synthesized copolymer for the first time. Optimization of the experiments were carried out by design of experimental methods. For investigation of the effect of reaction variables on water absorbency of the hydrogels, the synthetic conditions were systematically optimized through studying the influential factors, including , dose rate irradiation and concentration of monomer and alginate. The effect of grafting variables were systematically optimized to achieve a hydrogel with a maximum swelling capacity. The swelling of superabsorbent hydrogels was measured in various solutions with pH values ranging from 1 to 13. Factors which influence the water uptake of hydrogel such sensitivity to the salt solution, swelling kinetics in distilled water, PH reversibility and on–off switching were investigated. The hydrogel was characterized using FTIR spectroscopy, TGA and SEM.The hydrogel behaviour is influenced by two main parameters, ie grafting percentage and extent of crosslinking. By increasing these two parameters the extent of uptake, is reduced. Generally environmental factors such as ionic strength, Ph, partical size of hydrogel and chemical structure of the swelling medium can influence the adsorption capacity of the hydrogel
