Effect of partial delignification on defibrillation of Brassica Campestris straw and its performance in transparent film

The study on preparation of lignin-containing cellulose nanofiber (LCNF) with high-yield, high-efficient, low-cost is a great challenge in large-scale production. Regulating hydrogen-bonding network by changing the content of lignin is of great significance to improve the efficiency of defibrillation of cellulose. In this paper, the LCNF with high yield (91.55%) was fabricated by oxidizing Brassica Campestris (BC) straw to partially remove the lignin, followed by ball-milling and high-density ultrasonic treatment. The atomic force microscope results reveal that LCNF exhibit fiber network structure with a typical diameter of 2-5 nm similar to those of elementary crystallites. Variations in the structure and hydrogen bonding characteristics of the products are further determined based on the FT-IR results followed deconvolution fitting, showing that intra and intermolecular hydrogen-bonding energies and distances decrease with the increase of degree of oxidization. Furthermore, the LCNF films with high tensile strength (225.78 MPa), good UV-blocking (80%) and water-resistant were constructed by vacuum assisted filtration. This research will provide an effective and convenient approach to obtain the LCNF materials with high-yield and widen its application fields.