Cellulose nanocrystals reinforced κ-carrageenan based UV resistant transparent bionanocomposite films for sustainable packaging applications.

In this work, κ-carrageenan bionanocomposite films were prepared by solution casting of a mixture of κ-carrageenan, glycerol, and various amounts of cellulose nanocrystals (CNCs, 0-9 wt.%). The structure and morphology of the bionanocomposite films were characterized by Fourier-transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, and scanning electron microscopy. Compared with κ-carrageenan films, the κ-carrageenan bionanocomposite films showed better mechanical and barrier properties (water and UV) and thermal stability. The water contact angle increased from 23.30° to 71.80° and the water vapor permeation decreased from 8.93 gm-1 s-1 Pa-1 to 4.69 × 10-11 gm-1 s-1 Pa-1 in the κ-carrageenan films loaded with 9-7 wt.% CNCs, respectively. The tensile strength and elongation at break of the films increased from 38.33 ± 3.79 MPa to 52.73 ± 0.70 MPa and from 21.50 ± 3.72% to 28.27 ± 2.39%, respectively, after CNC loading increased from 0 wt.% to 7.0 wt.%. These results indicated that the κ-carrageenan nanocomposite films have potential applications in food packaging.