Eco-Friendly Preparation of Hydrophobic and Flexible Nanocellulose Fibers without Further Modification

These non-modified hydrophobic and lipophilic nanocellulose fibers (CNFs) are clean and efficient and prepared using alternating boiling of biological solutions (pectin lyase and chemical additives) and weak acid solution (i.e., sodium chlorite and acetic acid), which enrich the source of nanocellulose and reduce the environmental pollution caused by the preparation process. The prepared CNFs were systematically characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectrum, cellulose component analysis, small-angle X-ray scattering, X-ray diffraction, contact angle (CA), rheological energy, toxicity, and volume distribution. The best yield of CNFs was 40.64%, with a low crystallinity of 58.57% and a high volume distribution of 14%. The CNFs are extracted by this alternate cooking with weak acid solution and biological solutions, which solves the low productivity and high pollution caused by traditional inorganic chemical acid, without solid acid pollution, and meets the requirements of material cleaning and finishing. The water CA and oil CA of CNFs were 110 and 13.7°, respectively. It indicated that the CNFs prepared by this method can be hydrophobic without further modification. The CNFs are non-toxic and have good cytocompatibility based on the toxicity test result. It has a great possibility for using in the field of medical materials.