New Protein-Based Hydrogel with Superabsorbing Properties: Effect of Monomer Ratio on Swelling Behavior and Kinetics

In this paper we report an efficient synthesis of hydrolyzed collagen-g-poly(sodium acrylate-co-2-hydroxyethyl acrylate) hydrogel through chemical cross-linking by graft copolymerization of these two monomers onto the protein backbone in the presence of a cross-linker. Infrared spectroscopy and thermogravimetric analysis (TGA) were carried out to confirm the chemical structure of the hydrogel. Moreover, morphology of the samples was examined by scanning electron microscopy (SEM). To investigate the effect of monomer ratio on swelling behavior in various media three hydrogels with different acrylic acid/2-hydroxyethyl acrylate (AA/HEA) weight ratios were synthesized and swelling capacity was assessed. Moreover, the swelling of hydrogels were measured in solutions with pH ranging 1 to 12, and additionally, the swelling kinetics of the synthesized hydrogels were studied. The absorbency under load (AUL) of hydrogel was also investigated by using an AUL tester at various applied pressures.