Extraction of cellulose nanocrystals from areca waste and its application in eco-friendly biocomposite film

Abstract

Areca nut husk fibers are easily available and they are abundant agricultural waste, whose utilization to high value products needs more attention. The present study aims at the extraction of cellulose nanocrystals (CNCs) from areca nut husk fibers and the evaluation of its reinforcement capacity in polyvinyl alcohol (PVA) and chitosan (CS) film. The CNC showed rod-like structures, which were confirmed by TEM and AFM analysis. The diameter of the isolated CNC was 19 ± 3.3 nm; the length was about 195 ± 24 nm with an aspect ratio of 10.2 ± 6.8. The zeta potential of CNC was −15.3 ± 1.2 mV. Fourier Transform Infrared Spectroscopy analysis showed that the non-cellulosic compounds were effectively eliminated, and the X-ray diffraction results showed that CNC had higher crystallinity than the raw, alkali, and the bleached fibers. Thermogravimetric analysis revealed good thermal stability for the CNC. Moreover, the effects of the incorporation of CNC on the optical and tensile behaviours of the bionanocomposite film were investigated. The bionanocomposite film retained the same transparency as the PVA/CS film, indicating that the CNC was disseminated evenly in the film. The incorporation of CNC (3 wt%) to the PVA/CS film enhanced the tensile strength of the bionanocomposite film (9.46 ± 1.6 MPa) when compared to the control films (7.81 ± 1.4 MPa). Furthermore, the prepared nanobiocomposite film exhibited good antimicrobial activity against foodborne pathogenic bacteria and postharvest pathogenic fungi. These findings suggest that the bionanocomposite film might be suitable for food packaging applications.