Preparation and characterization of chitosan based hydrogels chemical cross‐linked by oxidized cellulose nanowhiskers

A novel hydrogel with superior mechanical properties were prepared using chitosan chemical cross‐linked with oxidized cellulose nanowhiskers (CNWs). An increased cross‐linking degree (6–40%) between chitosan and oxidized CNWs was found with the increased oxidation level of CNWs. A series of experiments were performed to evaluate the effect of oxidation level of CNWs on hydrogel properties. The morphology results showed that the cross‐linking reaction increased the hydrogels network density and the porous structure showed more compact and regular. Besides, the change in the morphology properties has an influence on hydrogels swelling behavior, exhibiting relatively reduced water content, and swelling ratio. The rheological measurements exhibited 263% and 394% improvements in storage modulus and loss modulus, respectively, and the maximum compressive stress confirmed an increasement by about 509%, were observed from the hydrogels cross‐linked by oxidized CNWs, compared with noncross‐linked hydrogels. Moreover, the resistance toward thermal degradation of the chitosan hydrogels was also increased by chemical cross‐linking. POLYM. COMPOS., 40:2432–2440, 2019. © 2018 Society of Plastics Engineers