Monitoring fibrillation in the mechanical production of lignocellulosic micro/nanofibers from bleached spruce thermomechanical pulp

The present work aims at assessing the main characteristics of lignocellulosic micro/nanofibers (LCMNF) from bleached thermomechanical pulp (BTMP) from spruce while glimpsing the suitability of cationic demand (CD) as effective monitoring parameter of the fibrillation process. For this, BTMP was mechanically refined at different times in a Valley beater, aiming at determining the required refining time and fiber length to be later fibrillated in a high-pressure homogenizer. It was found that 150 min treatment is required to avoid clogging in the pressure chambers of the homogenizer. The mechanically treated BTMP was gradually passed through a high-pressure ho-mogenizer, leading to four LCMNF with different fibrillation degree. The main characteristics of the LCMNF were determined, as well as the effect that high-pressure homogenization may generate onto the LCMNF structure. It was observed that CD is a robust parameter to monitor the fibrillation process, as it is a good indicator of the LCMNF characteristics. In addition, it was found that WRV may not be a good indicator of the extent of fibrillation for LCMNF, as the lignin content varies with the homogenization intensity. Finally, the limitations of CD as mon-itoring parameter and perspectives on this regard are provided to the reader. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study assessed the main characteristics of lignocellulosic micro/nanofibers from bleached thermomechanical pulp while considering cationic demand as an effective monitoring parameter of the fibrillation process. The mechanically treated pulp was passed through a high-pressure homogenizer to produce different fibrillation degrees of LCMNF, with CD identified as a robust parameter for monitoring the process. WRV was found to not be a reliable indicator of fibrillation extent due to lignin content variations.