Preparation and characteristics of sodium alginate/Na⁺rectorite- g-itaconic acid/acrylamide hydrogel films

Sodium alginate/Na⁺rectorite-graft-itaconic acid/acrylamide (SA/Na⁺REC-g-IA/AM) hydrogel film was prepared via solution polymerization. The effect of Na⁺REC, KPS, and NMBA content and the ratio of IA to AM on graft ratio, graft efficiency and absorption of liquids were investigated. The structure and morphology were analyzed by FTIR, XRD, TEM and SEM. Results revealed that the optimal Na⁺REC, KPS, and NMBA content and the ratio of IA to AM were 2 wt%, 0.8 wt%, 0.38 wt% and 4, respectively. The hydrogel film was found to exhibit an intercalative structure and coarse surface. The mechanism of graft copolymerization was discussed. A slower and more continuous release of salicylic acid for SA/Na ⁺REC-g-IA/AM composite hydrogel film was shown in vitro drug-controlled release studies, in comparison with SA film. The salicylic acid release mechanism of SA/Na⁺REC-g-IA/AM hydrogel film followed Fickian diffusion.