Synthesis of pH-Sensitive Hydrogel Based on Starch-Polyacrylate Superabsorbent

Abstract

In this article, we synthesize of a novel starch-based superabsorbent hydrogel via graft copolymerization of mixtures of acrylic acid (AA) and 2-Hydroxy ethyl methacrylate (HEMA) onto starch backbones. The polymerization reaction was carried out in an aqueous medium and in the presence of ammonium persulfate (APS) as an initiator and N,N’-methylene bisacrylamide (MBA) as a crosslinker. The hydrogel structures were confirmed by FTIR spectroscopy. Furthermore, the swelling of superabsorbing hydrogels was examined in solutions with pH values ranging between 1 and 13. It showed a reversible pH-responsive behavior at pHs 2 and 8. This on-off switching behavior makes the synthesized hydrogels as an excellent candidate for controlled delivery of bioactive agents. A proposed mechanism for hydrogel formation was suggested and the structure of the product was established using FTIR and SEM spectroscopies.