Preparation of composite films based on chitosan and surface-deacetylated chitin nanofibers

Biodegradable polymers, derived from renewable components, are useful in the development of
packaging materials to enhance quality and safety of food products. Among various biopolymers, chitosan has gained increasing interest because of its biodegradability and antimicrobial activities. Nevertheless,
neat chitosan films possess poor mechanical and barrier properties, which limits its packaging applications.
To overcome these drawbacks, the incorporation of reinforcing nanofillers in chitosan would be promising.
In this study, surface-deacetylated chitin nanofibers (ChNFs) were used as a reinforcing agent in chitosan films. ChNFs were successfully extracted from shrimp shells through the chemical treatment and mechanical defibrillation. Field emission scanning electron microscope (FE-SEM) showed that ChNFs were well-dispersed in an aqueous solution due to electrostatic repulsion. The chitosan-based composite films with various concentrations of ChNFs were prepared via solvent casting method, and effect of ChNFs concentrations (0‒10 wt %) on transparency and mechanical properties of the chitosan composite films was evaluated. The results revealed that the addition of 5 wt % ChNFs significantly enhanced tensile strength and Young’s modulus of the chitosan composite films by 83 and 78%, respectively, in comparison with those of the neat chitosan films. However, the addition of ChNFs deteriorated transparency of the composite films in comparison to that of the neat chitosan films.