University of Oulu

Juho Antti Sirviö, Anu Maria Kantola, Ari Ämmälä, Cellulose nanofibers from nonbleached and hydrogen peroxide bleached acidic thiourea treated sawdust, Journal of Cleaner Production, Volume 423, 2023, 138824, ISSN 0959-6526,

Cellulose nanofibers from nonbleached and hydrogen peroxide bleached acidic thiourea treated sawdust

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Author: Sirviö, Juho Antti1; Kantola, Anu Maria2; Ämmälä, Ari1
Organizations: 1Fibre and Particle Engineering Research Unit, University of Oulu, P.O. Box 4300, 90014, Oulu, Finland
2NMR Research Unit, University of Oulu, P.O.Box 3000, FIN-90014, Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 4.4 MB)
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Language: English
Published: Elsevier, 2023
Publish Date: 2023-10-31


Here a single-step acidic thiourea delignification without and with sequential hydrogen peroxide bleaching were used as a pre-treatment for producing low-lignin-containing cellulose nanofibers (LCNF) and bleached cellulose nanofibers (BCNF), respectively. Without bleaching, LCNF contained 7 wt% lignin, resulting in a slightly yellowish color in both the water dispersion and film. Despite low gravimetric yield of nanosize fibers, 23 wt% after microfluidization, the LCNF films exhibited notable mechanical strength, with a tensile strength of 174 MPa and a modulus of 11 GPa. Upon introducing an additional bleaching step, the color was eliminated, reducing the lignin content to 3 wt%. This adjustment also led to a significant increase in the gravimetric yield of nanofibers, reaching 78 wt%. The BCNF films demonstrated even higher mechanical performance, with a tensile strength of 207 MPa and a modulus of 12 GPa. LCNF film exhibited a higher contact angle (≈70°) than BCNF (≈60°), presumably due to the higher lignin content of the nonbleached pulp. Furthermore, hot pressing of the films at 150 °C for 18 min substantially enhanced the wet strength of the films by over 50%, attributed to the residual lignin.

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Series: Journal of cleaner production
ISSN: 0959-6526
ISSN-E: 1879-1786
ISSN-L: 0959-6526
Volume: 423
Article number: 138824
DOI: 10.1016/j.jclepro.2023.138824
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
Funding: Part of the work was carried out with the support of the Centre for Material Analysis, University of Oulu, Finland.
Copyright information: © 2023 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (