Synthesis, characterization and swelling behavior investigation of gela-tin-g-poly(acrylic acid-co-itaconic acid)

A novel pH-responsive superabsorbent hydrogel based on gelatin was prepared through cros-slinking copolymerization of poly (acrylic acid) and poly (itaconic acid). The copolymerization conditions including monomers, initiator, gelatin and crosslinker concentration, reaction temper-ature, and neutralization percent were systematically optimized to achieve a hydrogel with swel-ling capacity as high as possible. The hydrogels structure was confirmed using Fourier-transform infrared, thermogravimetric analysis, differential scanning calorimetric and scanning electron microscopy. The swelling of the superabsorbing hydrogel was examined in buffer solutions with pH ranged 3-12. Moreover, the swelling of the hydrogel was conducted in 0.15 M aqueous solu-tions of NaCl, CaCl2, and AlCl3. Due to the high swelling capacity in salt solutions, the hydrogel may be referred to as "low-salt sensitive" superabsorbent.