Synthesis, Swelling, Diffusion and Cationic Dye Adsorption Studies of Semi-IPN Sodium Alginate/Poly(HEMA-co-MA) Hydrogels

In this study, the novel pH-sensitive s-IPN consist of sodium alginate integrated with poly(HEMA-co-MA) hydrogel matrix are prepared by using two-step methodology. In the first step, 2-hydroxyethyl methacrylate (HEMA)/maleic acid (MA) copolymeric hydrogels are prepared by gamma radiation polymerization. Then, poly(HEMA-co-MA) hydrogel was immersed in sodium alginate solution (SA) and finally gamma radiation polymerization was carried out. The swelling, pH-sensivity and diffusion properties of the prepared s-IPN gels in deionized water and in dye solutions were investigated. Methylene Blue (MB) was used as a model dye. MB adsorption capacities of the hydrogels were found to be 0.26, 0.40 and 13.77 mg MB/g dry gel in PHEMA, P(HEMA-co-MA) and s-IPN SA/P(HEMA-co-MA) hydrogels, respectively. MB release data was fitted to various kinetic models to study the dye release behavior. The MB release from all the prepared hydrogels fitted the Korsmeyer-Peppas model. Swelling, diffusion and MB adsorption properties of the new s-IPN hydrogel were improved with the inclusion of SA and MA in the gel structure.