Multifunctional hybrid composite films based on biodegradable cellulose nanofibers, aloe juice, and carboxymethyl cellulose

Abstract

Cellulose nanofibers isolated from birch kraft pulp were incorporated into carboxymethyl cellulose-based films as a mechanical strength enhancer, and aloe juice was used as an antibacterial agent. Fourier-transform spectroscopy was performed and indicated the presence of hydrogen bonds that enhance the intermolecular interactions between the carboxymethyl groups and cellulose nanofibers in the prepared film. The incorporation of 5 wt% cellulose nanofibers significantly increased the tensile strength to 21-fold that of films lacking the nanofibers. The addition of aloe juice resulted in films with strong antibacterial activities against E. coli and S. aureus that prolong the shelf life of fresh pork. Cellulose nanofibers and aloe juice both increase the thermal stability and glass transition temperature of the carboxymethyl cellulose-based films, with little effect on the whiteness, transmittance, and wettability of these films. The rheological properties were characterized and revealed competitive interactions between cellulose nanofibers, carboxymethyl cellulose-based films, and aloe juice. The results show that the modified film is a promising material for use in food packaging.