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Licensed Unlicensed Requires Authentication Published by De Gruyter May 16, 2012

Optical properties of thermomechanical pulp (TMP) obtained from sulfite-pretreated Norway spruce with focus on two-photon spectral imaging (TPSI)

  • Jonas Hafrén EMAIL logo , Erik Nelsson , Hans C. Gerritsen and Arjen N. Bader
From the journal Holzforschung


Chips of Norway spruce have been impregnated with Na2SO3 and refined at two specific energy consumptions levels at full mill scale. The optical properties of thermomechanical pulps (TMPs) obtained were analyzed in terms of brightness, light scattering, opacity, and autofluorescence by spectral imaging. Even at low sulfite dosage (0.24% sulfite by dry weight) light absorption was reduced, and the brightness was elevated, and a clear dose-response effect was observed. Two-photon spectral imaging (TPSI) showed that sulfonation, impregnation, and refining affect the fluorescence properties differently. Compared to native wood, both processed wood chips and pulp fibers revealed blue-shifted fluorescence maxima, a characteristic of shortened conjugated systems. Two subpopulations of fibers with different optical properties were observed, and the fluorescence of one fiber population was red shifted.

Corresponding author. Department of Forest Products, Swedish University of Agricultural Sciences, Box 7008, SE-75007 Uppsala, Sweden

Received: 2011-9-16
Accepted: 2012-4-11
Published Online: 2012-05-16
Published in Print: 2012-10-01

©2012 by Walter de Gruyter Berlin Boston

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