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.
Original language | English |
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Pages (from-to) | 477-483 |
Journal | Holzforschung |
Volume | 66 |
Issue number | 4 |
DOIs | |
Publication status | Published - 2012 |
MoE publication type | A1 Journal article-refereed |
Keywords
- electron paramagnetic resonance
- free radicals
- hexenuronic acid
- lignin
- Masuko refining
- mechanoradicals
- nanofibrillated cellulose
- UV resonance Raman spectroscopy