Enhanced swelling and responsive properties of an alginate-based superabsorbent hydrogel by sodium p-styrenesulfonate and attapulgite nanorods

In this work, a series of sodium alginate-g-poly(sodium acrylate-co-sodium p-styrenesulfonate)/attapulgite (NaAlg-g-poly(NaA-co-NaSS)/APT) superabsorbent composites were prepared by graft copolymerization using N,N'-methylenebisacrylamide (MBA) as a crosslinker and ammonium persulfate as an initiator. Fourier transform infrared spectroscopy revealed that NaA and NaSS had been grafted onto NaAlg, and APT participated in polymerization reaction through reactive -OH groups. The introduction of proper amount of NaSS and APT induced the improved surface morphology, swelling capacity, and swelling rate. Moreover, the swelling behaviors of the superabsorbent composites were remarkably influenced by various salt medium, pH buffer solutions and organic solvents, and especially an intriguing swelling-deswelling behavior was observed with altering water/organic solvent ratio.