Cross-linking of cellulose nanofiber films with glutaraldehyde for improved mechanical properties

In this work, we present a method to improve the mechanical properties of CNF films by replacing the secondary hydrogen bonding in CNF films with glutaraldehyde (GA)-based covalent bonds using acidic catalysts. The CNF film treated with GA exhibits similar to 180% higher tensile strength than that for the untreated CNF film. In terms of the elastic modulus, the film shows a value of 12.3 GPa, which is similar to 160% higher compared to the untreated CNF film. Using Fourier transform infrared (FTIR) and X-ray diffraction (XRD) analyses on the films, it was found that the mechanical properties of the GA-treated films were significantly affected by the relationship between the degree of GA cross-linking and the reduction in the crystallinity index of the CNFs. (C) 2019 Elsevier B.V. All rights reserved.