Shaping the Future: Surface-Modified Cellulose Nanofibrils (CNFs) for Multifunctional 3D-Printable Hybrid Materials

Abstract

Cellulose nanofibrils (CNFs) are well-known biodegradable, renewable, and biocompatible materials that can be extracted from lignocellulosic materials via various chemical, mechanical, or enzymatic processes. Typically, CNFs obtained by mechanical processes are in aqueous media, generating viscous dispersion. The abundant numbers of hydroxy groups on their surface are a double-edged sword when utilizing CNFs: while those functions lead to some drawbacks such as hygroscopic character, instability in many organic solvents, strong interfibrillar hydrogen interactions (leading to fibril aggregation), they can also participate in many chemical modifications through specific reactions. This thesis presents a surface modification pathway for CNFs, beginning with their conversion into CNF-based macroinitiators (CNF-MI) in a single step, followed by a Cu0-mediated radical polymerization (SET-LRP) to graft polymers onto the CNF surface. The introduction of polymers onto their surface allows to change the properties and the behavior of the CNF drastically. By carefully selecting the appropriate monomers, CNF can be adapted and is suitable for many applications.