Synthesis and absorbency of gelatin-graft-poly(sodium acrylate-co-acrylamide) superabsorbent hydrogel with saltand pH-responsiveness properties

Abstract

Abstract:In this article, we synthesize a novel gelatin-based superabsorbent hydrogel via graft copolymerization of mixtures of acrylic acid (AA) and acrylamide (AAm) onto gelatin 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. The effect of grafting variables, i.e. concentration of MBA and APS, AA/AAm weight ratio, and reaction time and temperature, was systematically optimized to achieve a hydrogel with swelling capacity as high as possible. The swelling behavior of these absorbent polymers was also investigated in various salt solutions. Results indicated that the swelling capacity decreased with an increase in the ionic strength of the swelling medium. Furthermore, the swelling of superabsorbing hydrogels was examined in solutions with pH values ranging between 1.0 and 13.0. It showed a reversible pH-responsive behavior at pHs 2.0 and 7.0. This on-off switching behavior makes the synthesized hydrogels an excellent candidate for controlled delivery of bioactive agents. Finally, the swelling kinetics of the synthesized hydrogels with various particle sizes was preliminarily investigated.

Preparation and swelling behavior of pH-sensitive and saltresistant amphoteric semi-IPNs hydrogels based on starch phosphate and poly[2-[(methacryloyloxy) ethyl] trimethylammonium] chloride

“…To further increase the content of crosslinker will decrease the space between the polymer chains, and the resulted hydrogel could not be expanded enough. Similar trend has been reported in previous work [10]. However, in this work, it was found the optimal content of crosslinker was less than that in other case [18].…”

“…Material's biodegradability has been focused because of the renewed attention to environmental protection issues [9,10]. As a result, starch, as a natural macromolecule, is widely used in superabsorbent hydrogels by graft copolymerization of hydrophilic monomers.…”

Protein‐ and homo poly(amino acid)‐based hydrogels with super‐swelling properties

“…[35] Gelatin-g-poly(NaAA-cl-AM) hydrogel was synthesized through simultaneous crosslinking and graft polymerization of AA/AM mixtures onto gelatin. [36] The optimum reaction conditions to obtain maximum swelling (275 g/g in deionized water) were found to be MBA 0.043 M, AA 0.49 M, AM 0.13 M, APS 0.02 M, 608C, and 180 min. The hybrid hydrogels in 0.15 M salt solutions showed appreciable swelling capacity (e.g.…”

Novel superabsorbent copolymers of partially neutralized methacrylic acid and acrylonitrile: synthesis, characterization and swelling characteristics

“…[3][4][5][6][7][8] Hence, they find increasing applications in bioseparations and in controlled drug delivery systems. [9][10][11] Hydrogels can be neutral, anionic, or cationic as determined by the pendant groups incorporated in the backbone. The network rendered hydrophilic by the presence of functional groups such as hydroxyl (-OH), carboxylic (-COOH), amidic (-CONH-), sulfonic (-SO 3 H), etc.…”