Synthesis and characterization of acrylamide-co-acrylic acid copolymeric hydrogels

The influence of type and content of crosslinkers and the degree of neutralization on swelling and rheological properties of Acrylamide-co-Acrylic acid (AAm-co-AAc) hydrogels was studied. AAm-co-AAc copolymeric hydrogels were synthesized by solution copolymerization initiated by ammonium persulphate (APS) as thermal initiator. Two types of crosslinkers : N,N-methylenebisacrylamide (MBAAm) and polyethylene glycol diacrylate-250 (PEGDA-250) were used. The swelling properties of prepared hydrogels were examined by gravimetric measurement and the flow properties were investigated by Brookfield viscometer. The effect of crosslink density and crosslinker type on the swelling behavior and viscosity of the hydrogels were discussed. Both swelling and viscosity of these hydrogels were sensitive to the degree of neutralization. Flow curves indicated that these gels exhibit a pseudoplastic behavior and their rheological properties can be described by power law model.