Mechanochemical modification of cellulose nanocrystals by tosylation and nucleophilic substitution

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 modifi...

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Bibliographic Details
Published inGreen chemistry : an international journal and green chemistry resource : GC Vol. 26; no. 18; pp. 9823 - 9832
Main Authors Langerreiter, Daniel, Attallah, Nashwa L., Schlapp-Hackl, Inge, Kostiainen, Mauri A., Kaabel, Sandra
Format Journal Article
LanguageEnglish
Published Cambridge Royal Society of Chemistry 01.01.2024
Subjects
Amines
Ball milling
Biopolymers
Cellulose
Cellulose esters
Crystals
Esters
Nanocrystals
Nanomaterials
Nanostructured materials
Nanotechnology
Parameter modification
Solvents
Substitution reactions
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Summary: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.
ISSN:1463-9262
1463-9270
DOI:10.1039/D4GC03378G