University of Oulu

ACS Appl. Mater. Interfaces 2017, 9, 3, 2846-2855

Cellulose nanofibrils from nonderivatizing urea-based deep eutectic solvent pretreatments

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Author: Li, Panpan1; Sirviö, Juho Antti1; Haapala, Antti2;
Organizations: 1Fibre and Particle Engineering Research Unit, University of Oulu, P. O. Box 4300, FI-90014 Oulu, Finland
2Wood Materials Science, University of Eastern Finland, P. O. Box 111, FI-80101 Joensuu, Finland
Format: article
Version: accepted version
Access: open
Online Access: PDF Full Text (PDF, 4.3 MB)
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Language: English
Published: American Chemical Society, 2017
Publish Date: 2019-12-03


Deep eutectic solvents (DESs) are a fairly new class of green solvents applied in various fields. This study investigates urea-based DES systems as novel pretreatments for cellulose nanofibril production. In the experiments, deep eutectic systems having urea and ammonium thiocyanate or guanidine hydrochloride as a second component were formed at 100 °C and then applied to disintegrate wood-derived cellulose fibers. The DES-pretreated fibers were nanofibrillated into three different levels of mechanical treatments with a microfluidizer, and their properties were analyzed. Moreover, nanofibril films were fabricated by solvent casting method. Both DES systems were able to loosen and swell the cellulose fiber structure as indicated by the increase in the lateral dimension of the fibers. Nonpretreated birch cellulose fibers had difficulties in mechanical nanofibrillation as clogging of the chamber occurred often. However, cellulose nanofibrils with widths ranging from 13.0 to 19.3 nm were successfully fabricated from DES-pretreated fibers with both systems. Translucent nanofibril films generated from DES-pretreated cellulose nanofibrils had good thermal stability and mechanical properties, with tensile strengths of approximately 135–189 MPa and elastic modulus of 6.4–7.7 GPa. Consequently, both urea-based DESs showed a high potential as environmentally friendly solvents in the manufacture of cellulose nanofibrils.

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Series: ACS applied materials & interfaces
ISSN: 1944-8244
ISSN-E: 1944-8252
ISSN-L: 1944-8244
Volume: 9
Issue: 3
Pages: 2846 - 2855
DOI: 10.1021/acsami.6b13625
Type of Publication: A1 Journal article – refereed
Field of Science: 215 Chemical engineering
Funding: The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acsami.6b13625.
Copyright information: This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS applied materials & interfaces, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see