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. [ABSTRACT FROM AUTHOR]