Comparative study on the properties of cross‐linked cellulose nanocrystals/chitosan film composites with conventional heating and microwave curing

Cross‐linking of chitosan film composites was carried out by using conventional heating and microwave curing methods in this study. Non‐cross‐linked and glutaraldehyde (GA) cross‐linked neat chitosan and cellulose nanocrystals (CNC)/chitosan film composites were cured by either conventional oven heating or microwave irradiation. Tensile strength and Young's modulus of chitosan composites were enhanced significantly by the addition of CNC and GA especially for the microwave‐cured samples. The changes in chemical interaction of the chitosan film composites was determined by Fourier transform infrared (FTIR) spectroscopy. The microwave‐cured GA‐cross‐linked chitosan film composites were more thermally stable than non‐cross‐linked and conventionally heated GA‐cross‐linked chitosan film composites due to the formation of a more stable structure between GA and chitosan. Nevertheless, the reduced antimicrobial efficacy of film composites against Escherichia coli, Bacillus subtilis, and Saccharomyces cerevisiae was observed in cross‐linked film composites compared with non‐cross‐linked composites.