Swelling and mechanical properties of superabsorbent hydrogels based on Tara gum/acrylic acid synthesized by gamma radiation.

The main objective is to develop a new superabsorbent system especially for using in diaper applications. In this study, hydrogels based on Tara gum/acrylic acid (TG/AAc) were prepared by gamma irradiation, in the presence of N,N'-methylenebisacrylamide (MBAAm) as a crosslinking agent. The polymeric networks formed were characterized by FT-IR and evaluated by swelling studies as a function of MBAAm concentration, temperature and nature of the swelling medium. The swelling kinetics of the hydrogels was studied in terms of the diffusion exponent "n". The results showed that the water diffusion into hydrogels is a non-Fickian type. Mechanical measurements (stress-strain) curves of hydrogels were evaluated to calculate the shear modulus values and the average molecular weight between crosslinks (Mc). Moreover, the absorption under load at 37°C of water and urea aqueous solutions (as a major component of urine) by TG/AAc hydrogels was determined.