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Licensed Unlicensed Requires Authentication Published by De Gruyter December 13, 2011

Mechanoradical formation and its effects on birch kraft pulp during the preparation of nanofibrillated cellulose with Masuko refining

Iina Solala, Aleksander Volperts, Anna Andersone, Tatiana Dizhbite, Nina Mironova-Ulmane, Annikki Vehniäinen, Jaakko Pere and Tapani Vuorinen
From the journal

Abstract

Masuko refining of unbleached kraft birch pulp has been noted to result in more thorough fibrillation than the refining of its bleached counterpart. This result is observed through different fractionation behavior of once refined pulps and is further supported by different relative changes in pulp viscosity. The formation of mechanoradicals during refining is observed with electron paramagnetic resonance spectroscopy, and the role of lignin and hemicelluloses [quantified using kappa number determination and UV resonance Raman (UVRR) spectroscopy] in the progress of refining is discussed. Lignin, a known antioxidant, is capable of stabilizing radicals, which could potentially counteract recombination reactions between highly reactive cellulose radicals. On the other hand, lignin’s ability to promote fibrillation could also lie in its amorphous nature and not solely in its antioxidant characteristics. Furthermore, bleaching removes not only lignin but also hemicelluloses, which affects both the charge density and the structure of the fiber material, and this is another likely contributor to the easier fibrillation of lignin-containing pulps.


Corresponding author. Department of Forest Products Technology, School of Chemical Technology, Aalto University, P.O. Box 16300, 00076 Espoo, Finland

Received: 2011-10-6
Accepted: 2011-11-8
Published Online: 2011-12-13
Published in Print: 2012-05-01

©2012 by Walter de Gruyter Berlin Boston

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