Preparation of cellulose nanocrystals extracted from kenaf fiber with natural deep eutectic solvent

Abstract

The sustainable green approach is predominant and needed for developing functional nanomaterials. Thus, this article uses a green, non-toxic, and possible recovery chemical pre-treatment using a natural deep eutectic solvent to increase the productivity of isolated cellulose nanocrystals (CNC). Furthermore, extraction and characterization of CNC from kenaf fiber using a 2:1 molar ratio of lactic acid and choline chloride were performed. Indeed, various techniques like infrared Fourier transform spectroscopy, X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy, and transmission electron microscopy are used for the deep analysis/characterization of CNC. The results showed that the morphology created by an efficient natural deep eutectic solvent treatment produces CNC with rod and rectangular-shaped structures, whereas a nano-sized needle-like structure was observed in TEM analysis. X-ray results show a higher intensity peak at 22.66° of CNC, and the crystallinity of obtained CNC was 81.2%. Based on the findings, isolated CNC have better morphology. Furthermore, thermally stable CNC is produced compared to traditional CNC-isolated processes. Thus, we believe the green solvent used in the article for the isolation of CNC gives extra advantages compared to the traditional isolation process summarized in the literature.