University of Oulu

J. A. Sirviö and M. T. Visanko, J. Mater. Chem. A, 2017, DOI: 10.1039/C7TA05668K

Anionic wood nanofibers produced from unbleached mechanical pulp by highly efficient chemical modification

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Author: Sirviö, Juho Antti1; Visanko, Miikka1
Organizations: 1Fibre and Particle Engineering Research Unit, University of Oulu, P.O. Box 4300, 90014 Oulu, Finland
Format: article
Version: accepted version
Access: embargoed
Persistent link: http://urn.fi/urn:nbn:fi-fe201710038869
Language: English
Published: RSC Publishing, 2017
Publish Date: 2018-09-20
Description:

Abstract

Chemical modification of lignocellulosic materials, especially as a pre-treatment in nanocellulose production, has mainly been conducted with lignin-free bleached cellulose pulps. However, non-bleached pulp exhibits several advantages over bleached pulp, namely excluding of the use of hazardous bleaching chemicals, higher yield, and lower cost. In this study, the chemical modification of lignocellulose (groundwood pulp, GWP) with a high lignin content (27.4 wt%) was investigated using a deep eutectic solvent (DES) as a reaction medium. A low-melting DES was easily obtained within one hour by mixing triethylmethylammonium chloride (TEMACl) and imidazole at room temperature. Carboxylated GWP was obtained by adding succinic anhydride to the DES. In mild reaction conditions (2 h at 70 °C), carboxylic acid contents of 1.88–3.34 mmol/g were obtained depending on the anhydride dosage used (5–20 mmol/1 g of pulp) with excellent yield (over 90%). The GWP was more reactive in the pre-treatment step, measuring carboxylic acid contents higher than those of bleached cellulose pulps treated in identical reaction conditions (containing less than 0.5 wt% lignin). After deprotonation of the carboxylic acid groups, highly anionic wood nanofibers (AWNFs) were produced using a microfluidizer. Vacuum filtration was applied in the preparation of self-standing films, which had good mechanical properties and were transparent. The fabricated AWNFs have many potential uses—for instance, in sustainable water purification because of their adjustable surface charge.

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Series: Journal of Materials Chemistry A
ISSN: 2050-7488
ISSN-E: 2050-7496
ISSN-L: 2050-7488
DOI: 10.1039/C7TA05668K
OADOI: https://oadoi.org/10.1039/C7TA05668K
Type of Publication: A1 Journal article – refereed
Field of Science: 221 Nanotechnology
Subjects:
Copyright information: © The Royal Society of Chemistry 2017.