Superabsorbent Sponge and Membrane Prepared by Polyelectrolyte Complexation of Carboxymethyl Cellulose/Hydroxyethyl Cellulose-Al³⁺

A novel carboxymethyl cellulose/ hydroxyethyl cellulose-Al³⁺(CMC/HEC-Al³⁺) hydrogel was prepared through electrostatic complexing between the anionic polyelectrolyte CMC and cationic cross-linking agent Al³⁺. The structure and properties of the hydrogel were characterized using FTIR, TGA, and SEM. The viscoelasticities of the swollen hydrogel were measured using the rheology test. The results indicated that a porous network structure was formed in the hydrogel. The content of CMC, HEC, and Al³⁺can significantly affect its structure and characteristics. A sponge and membrane were prepared from the CMC/HEC-Al³⁺hydrogel by freeze-drying and oven drying, respectively. Their swelling behaviors were investigated in water and saline solutions, and quantified with a swelling kinetic simulation. The results indicated that electrostatic effects, physical entanglement, and intra- and intermolecular hydrogen bonds contributed to the cross-linking network structure, with the electrostatic effect acting as the dominant force. In all, both superabsorbent sponge and membrane prepared from CMC/HEC-Al³⁺hydrogel showed excellent swelling behavior and could be used in dressing wounds.