Salt sensitivity, pH responsivity and kinetic study of chitosan-g-PAA hydrogel

Acrylic acid (aa) monomer was directly grafted onto chitosan using ammonium persulfate (aps) as an initiator and methylenebisacrylamide (mba) as a crosslinking agent under an inert atmosphere. two factors affecting the swelling capacity of the obtained hydrogel, aa and mba concentrations, were studied. the polymer structures were characterized by ftir spectroscopy. maximum water absorbency of the optimized final product was found to be 434 gr/gr. also, i studed manner swelling of product in different solution salty. results shown that the swelling capacity decreased with increasing of ionic strength. farthermore, the swelling of superabsorbant hydrogel was measured in various solutions with ph values ranging from 1 to 12. the hydrogels exhibited the highest swelling at ph 3 and8. also the swelling kinetics in distilled water investigated.