The relationship between kappa number and oxidizable structures in bleached kraft pulps
2002 (English)In: Journal of Pulp and Paper Science (JPPS), ISSN 0826-6220, Vol. 28, no 8, 262-266 p.Article in journal (Refereed) Published
The relationship between residual oxidized lignin structures in spruce and birch kraft pulps and their kappa number contribution after each stage in an ODEQP (spruce) and an OQ(OP)Q(PO) (birch) sequence, respectively, has been investigated. Analysis by a modified kappa number method (OxDem kappa number) as well as by determination of permanganate oxidation equivalents on various isolated residual lignin samples revealed that the relationship between the lignin content and kappa number gradually changes as the bleaching sequence proceeds, giving values that differ substantially from that found in unbleached kraft pulp. These effects can be attributed to the successive oxidative fragmentation of aromatic rings and the formation of carboxyl and non-aromatic unsaturated structures in the residual lignin structure. Therefore, a kappa number determination on pulp which has been subjected to an oxidative stage will result in an underestimation of the lignin content.
Place, publisher, year, edition, pages
2002. Vol. 28, no 8, 262-266 p.
Betula, Bleached pulps, Chlorine free bleaching, Kappa number, Kraft pulps, Lignin content, Multistage process, Oxidation, Picea
Paper, Pulp and Fiber Technology
IdentifiersURN: urn:nbn:se:kth:diva-8862ISI: 000177411900003OAI: oai:DiVA.org:kth-8862DiVA: diva2:14330
QC 201010042005-12-022005-12-022010-10-04Bibliographically approved