A novel polyacrylamide nanocomposite hydrogel reinforced with natural chitosan nanofibers

Polyacrylamide (PAM) was used as a matrix material for fabricating novel nanocomposite hydrogels reinforced with natural chitosan nanofibers (CNFs) via in situ free-radical polymerization. The nanocompositeʹs structure, strength, morphology and rheological properties were investigated. The results showed that the CNFs had a strong interaction with PAM through hydrogen and covalent bondings. The CNFs acted as a multifunctional cross-linker and a reinforcing agent in the hydrogel system. The compression strength and storage modulus of the nanocomposite hydrogels were significantly higher than those of the pure PAM hydrogels and the corresponding PAM/chitosan semi-interpenetrating polymer network (PAM–SIPN) hydrogels. The swelling ratio (SR) of the nanocomposite hydrogels was lower than that of the PAM hydrogel, but was similar to that of the PAM–SIPN hydrogel. Among the CNF contents used, the 1.5 wt% CNF loading level showed the best combined swelling and mechanical properties for the hydrogels.