Defibrillation and film formation from partially delignified Brassica campestris stem

We prepared lignin-containing cellulose nanofibers (LCNFs) from Brassica campestris stem and report the properties of the LCNF films. Partial removal of lignin was achieved by oxidizing the stem, followed by ball-milling and high-intensity ultrasonic treatment. Reducing the lignin content from 26 to 20% in the starting material significantly improved the defibrillation efficiency of cellulose. The amount of residual lignin had little impact on the mechanical properties and water contact angle of LCNF films, but showed high UV-absorbance. Graphical abstract