Preparation and characterization of environmentally friendly agar/kappa-carrageenan/montmorillonite nanocomposite hydrogels

In the present study, for the first time, agar/kappa-carrageenan and agar/kappa-carrageenan/montmorillonite hydrogel materials were prepared by the free-radical crosslinking reaction of agar and kappa-carrageenan in the presence of triethylene glycol divinyl ether (TEGDE) as the crosslinker agent. Here, montmorillonite (MMT) modified with phenylalanine was used as additive agent. Agar/kappa-carrageenan hydrogel materials with and without MMT were characterized by FTIR, SEM and XRD analyses. The effect of free radical initiator (ammonium persulfate, APS) concentration, crosslinking agent (TEGDE) concentration, reaction temperature, polysaccharide ratio and MMT concentration on the swelling performance and surface property of hydrogel material was investigated and optimum reaction conditions were determined. Maximum equilibrium swelling capacity of the agar/kappa-carrageenan hydrogel was found to be 2523 % under the optimum conditions ([APS] = 5 x 10(-4) M, [TEGDE] = 5 x 10(-4) M, T = 70 degrees C and m(agar):m(kappa-carrageenan) = 1:4). An increase of the MMT content within hyrogel matrix led to a decrease in the swelling values of hydrogels. All of the hydrogels prepared in various formulations exhibited non-Fickian swelling behavior. New hydrogel materials obtained from this study could be potential candidates for biomedical applications.