Synthesis and Investigation of Swelling Behavior of Grafted Alginate/Alumina Superabsorbent Composite

In this study a novel alginate‐g‐poly(acrylic acid)/alumina composite was synthesized and characterized. Preparation of the composite hydrogels involved free radical polymerization of a combination of alginate, acrylic acid (AA) and distilled water, in appropriate amounts and N,N‐methylene bisacrylamide (MBA) as crosslinking agent. The composite formation was confirmed by Fourier transform infrared spectroscopic (FT‐IR). The surface morphologies of the synthesized hydrogels were assessed by scanning electron microscopy. Systematically, the different variables of the graft copolymerization were optimized to achieve maximum swelling capacity. The swelling of superabsorbent hydrogels was measured in various solutions with pH values ranging from 0 to 14. In addition, the pH reversibility, on–off switching behavior, swelling kinetics in distilled water and the absorbency under load (AUL) were investigated.