Functionalization and optimization of cellulose-based filaments
Time: Thu 2026-10-29 10.00
Location: F3 (Flodis), Lindstedtvägen 26
Language: English
Subject area: Fibre and Polymer Science
Doctoral student: Mu-Rong Wang , Fiberprocesser
Opponent: Prodessor Steve Eichhorn, University of Bristol, England
Supervisor: Professor L. Daniel Söderberg, Fiberprocesser, Wallenberg Wood Science Center; Doktor Korneliya Gordeyeva, Wallenberg Wood Science Center, Fiberprocesser; Docent Tomas Rosén, Wallenberg Wood Science Center, Fiberprocesser; Doktor Anastasia Riazanova, Wallenberg Wood Science Center, Fiberprocesser
QC 20261005
Abstract
Cellulose nanofibers (CNF) are among the most promising renewable building blocks for high-performance materials. The combination of TEMPO-mediated oxidized cellulose nanofibers (TCNF) with a flow-focusing channel yields the strongest bio-based filaments reported to date. This thesis follows TCNF filaments through their full processing life cycle: controlling the flowing dispersion, spinning parameters, drying temperature, recycling process, and functionalizing, and asking how each stage determines the structure and properties of the filaments.
The flowing dispersion is monitored in situ by integrating a flow-focusing geometry directly into a polarized optical microscope (POM). Spinnability is shown to be governed by the homogeneity of the fiber network rather than individual dimensions, providing a predictive criterion that replaces batch-by-batch trial-and-error testing. Post-spinning thermal drying reshapes filament structure and mechanics through two competing effects: moderate heating degrades performance, whereas high-temperature densification and co-crystallization restore strength to the single-fiber value. Circularity is addressed by redispersing dried filaments into a spinnable dispersion: blending with fresh TCNF restores colloidal stability and spinnability while retaining a large fraction of the original mechanical performance. Finally, the filaments are functionalized into carbon-fiber composites whose mechanical and thermal-transport behavior extends the flow-focusing platform from purely structural fibers toward functional, thermally conductive materials.
Together, these studies establish a coherent, resource-conscious framework for engineering the properties of bio-based cellulose filaments across their full life cycle, from the flowing dispersion to a recyclable, functional fiber.