The influence of various oxidizable structures on the brightness stability of the bleached chemical pulps
2006 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, Vol. 21, no 1, 49-53 p.Article in journal (Refereed) Published
The influence on the brightness stability of various oxidizable structures viz.: lignin, hexenuronic acid and other "non-lignin" structures in kraft Pulps was studied. Samples of pulp of different wood species (spruce, birch, eucalyptus) taken from TCF and ECF bleaching sequences were chemically characterised by kappa number fractionation and subjected to accelerated ageing. It was shown that the selective removal of all oxidizable structures of carbohydrate origin present in the pulp significantly improved the brightness stability. The thermal yellowing of the pulps was found to be proportional to the content of hexenuronic acid groups regardless of the pulp origin or bleaching history. Quantitative determination of the changes during ageing showed that 2-furancarboxylic acid and 5-formyl-2-furancarboxylic acid are formed in the course of decomposition of hexenuronic acid. The difference between the original amount of hexenuronic acid groups in a pulp sample and the sum of the remaining hexenuronic acid together with the 2-furancarboxylic acid and 5-formyl-2-furancarboxylic acid suggests that the latter are involved in further reactions leading to the formation of chromophoric structures. It was also found that 2,3-dihydroxy-2-cyclopenten-1-one (reductic acid) is formed during the ageing.
Place, publisher, year, edition, pages
2006. Vol. 21, no 1, 49-53 p.
bleaching, kraft pulp, 2-furancarboxylic acid, 5-formyl-2-furancarboxylic acid, hexenuronic acid, reductic acid, thermal yellowing
Paper, Pulp and Fiber Technology
IdentifiersURN: urn:nbn:se:kth:diva-8865ISI: 000236358800008ScopusID: 2-s2.0-33645678799OAI: oai:DiVA.org:kth-8865DiVA: diva2:14333
Uppdaterad från submitted till published: 20101005. QC 201010052005-12-022005-12-022014-12-17Bibliographically approved