|
Title
Use of nitrogen centered peroxide activators to increase the brightening potential of peroxide. II. Optimized conditions
Authors
Q. Y. Hu C. Daneault and S. Robert
Received
January 11, 2011
Published
Volume 45 Issue 5-6 May-June
Keywords
tetraacetylethylenediamine, TAED, hydrogen peroxide, activators, peroxyacetic acid, bleaching,
Abstract
This work focuses on a new TAED/H O bleaching system on spruce-balsam thermomechanical pulp, at low 2 2 consistency. The experiments show that the TAED/H O system improves the brightness of the softwood 2 2 thermo-mechanical pulp significantly (6% ISO), compared to the peroxide system alone. For each fixed molar ratio of TAED/H O , there is an optimum range for alkali addition, for achieving a maximum 2 2 brightness gain of the thermomechanical pulp, a well-defined linear correlation being found between the TAED/H O molar ratio and the optimal alkali charge. An optimal TAED/H O ratio is obtained at 0.7, 2 2 2 2 slightly higher than the theoretical value of 0.5, as due to the saponification reaction of TAED. TAED/H O 2 2 results in pulps being slightly more susceptible to light-induced yellowing in the UV and visible regions of the spectrum, at very long irradiation times. Short term light-induced yellowing is approximately the same for both kinds of pulps.
Link
|
