Issue 18, 2024

Mechanochemical modification of cellulose nanocrystals by tosylation and nucleophilic substitution

Abstract

Cellulose nanomaterials are derived from the most abundant biopolymer on earth, and are gaining importance in the shift from oil-based materials to sustainable alternatives. To facilitate this, sustainable methods to modify these renewable nanostructured materials must be explored, as surface modifications are prerequisite for many nanocellulose applications. Here, we present a solvent-free method for the surface modification of cellulose nanocrystals, encompassing mechanochemistry to convert uncharged or charged CNCs to tosylated CNCs, and for the subsequent versatile nucleophilic substitution with amines and esters. Systematic screening of the reaction parameters revealed key variables – milling time, base type and amount, for tosylation to take place during 60 minutes of ball-milling without major changes to CNC morphology and crystallinity. Both step-wise and one-step in situ nucleophilic substitution of the tosyl CNCs was successful with amine and ester modification. Our results demonstrate how fine-tuning the parameters of solvent-free methods can lead to fast and environmentally benign reactions on cellulose nanomaterials while retaining their structure on the nanoscale.

Graphical abstract: Mechanochemical modification of cellulose nanocrystals by tosylation and nucleophilic substitution

Supplementary files

Article information

Article type
Paper
Submitted
10 Jul 2024
Accepted
14 Aug 2024
First published
20 Aug 2024
This article is Open Access
Creative Commons BY license

Green Chem., 2024,26, 9823-9832

Mechanochemical modification of cellulose nanocrystals by tosylation and nucleophilic substitution

D. Langerreiter, N. L. Attallah, I. Schlapp-Hackl, M. A. Kostiainen and S. Kaabel, Green Chem., 2024, 26, 9823 DOI: 10.1039/D4GC03378G

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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