Synthesis and water sorption studies of pH sensitive poly(acrylamide-co-itaconic acid) hydrogels

Superabsorbent copolymers of acrylamide (Am) and itaconic acid (ItA) were prepared by free radical solution polymerization using sodium persulfate and N,N,N′,N′-tetramethylenediamine (TMEDA) as initiating system at 35 °C. Two series were prepared. The first series (SA series) used varied amount of itaconic acid and fixed amount of N,N′-methylenebisacrylamide (MBAm), while in the second series (SB series) the amount of (MBAM) changed and the amount of itaconic acid was fixed. The swelling behavior was studied at room temperature and the swelling percentage, swelling kinetics parameters such as initial swelling rate, swelling rate constant, and diffusion parameters were determined. The effect of pH and saline sensitivity on swelling behavior was also studied.