MODELLING OF AAm-co-ALGINATE HYDROGELS SWELLING KINETICS

Abstract

In this study, cross-linked acrylamide -co-alginat hydrogels were synthesized by free radical polymerization in aqueous solutions of acrylamide and of acrylamide with sodium alginate as comonomer. For each copolymerization, four different compositions were used and in all systems a concentration of a crosslinker such as oxalic acid and polyethylene glycol dimethacrylate (PEGDMA(500)) was employed. As a result of swelling tests, the influence of crosslinkers and the relative content of sodium alginate on the swelling properties in the hydrogels were examined and modeled. Acrylamide-co-alginate hydrogels were swollen in the range 12.72-25.52 g(water)/g(dry) (gel) in water, while acrylamide hydrogels swelled in the range 8.5-10.37 g(water)/g(dry gel). The swelling capacity was found to increase significantly with increase in alginate concentration. The diffusion coefficients (D) of acrylamide-co-alginat hydrogels was calculated in the range 3.39 x 10(-10) -4.34 x 10(-10) m(2) s(-1). The experimental swelling data was fitted to three models. The first order swelling kinetic model showed the best fit for all acrylamide-co-alginat hydrogels.