Enhancing the porous structure of swellable poly(acrylic acid-co-acrylamide) crosslinked by N-Maleyl chitosan via introducing foaming agents and non-ionic surfactant

Abstract

A fast-swelling porous poly (acrylic acid co-acrylamide) crosslinked by N-Maleyl chitosan superabsorbent hydrogels were prepared by free radical graft copolymerization reaction for partially neutralized acrylic acid (AA), acrylamide (Am) using ammonium persulphate (APS) as an initiator, and N-Maleyl chitosan (N-MACH) as crosslinker. The structure of the synthesized hydrogels were investigated by FTIR spectroscopy and scanning electron microscope (SEM). Acetone and sodium bicarbonate were used as porosity generator (porogens) during the polymerization process. Surfactant (span 80) was used as a micelle template and foam stabilizer. The swelling studies showed improvement of hydrogel behavior with increasing of crosslinker concentration. Otherwise, the porous structure and swelling rate of the hydrogels improved by the incorporation of acetone and NaHCO3. While the incorporation of span 80 in the gelling process can enhance the porosity structure. Morphological studies showed that the porosity generators and surfactant created highly porous structures. The density of all the highly porous superabsorbents hydrogels (HPSH) synthesized was ranged from 0.6 to 1.04 g/cm3. These HPSHs exhibited a higher rate of swelling at time range from 28 to 269 min.

Keywords

• Hydrogel
• Polymer
• Chitosan
• Foaming agents
• Surfactant