title: Differences in residual lignin properties between Betula verrucosa and Eucalyptus urograndis kraft pulps.
abstract: By comparing the ultrastructural features of two oxygen delignified hardwood kraft pulps (Eucalyptus urograndis and Betula verrucosa), we have demonstrated a marked difference in their residual lignin properties. In this study, properties such as crystallinity and crystal size of cellulose, molecular weights, carboxyl group contents, and carbohydrate compositions of the two kraft pulps were compared. The examined pulps were in our observations relatively similar. A significant difference, however, was observed in the size exclusion chromatography measurements, which indirectly suggested that a significant portion of residual lignin in eucalyptus pulp was associated with cellulose. Birch pulp, in contrast, exhibited a more conventional tendency for hardwood pulps: lignin mainly associated with hemicelluloses.
authors.affiliation: Helsinki University of Technology, Department of Forest Products Technology, Laboratory of Forest Products Chemistry, P.O.Box 6300, FIN-02015 TKK, Finland.
authors.forename: Tuomas A
authors.initials: TA
authors.lastname: Hänninen
authors.forename: Eero
authors.initials: E
authors.lastname: Kontturi
authors.forename: Akira
authors.initials: A
authors.lastname: Isogai
authors.forename: Tapani
authors.initials: T
authors.lastname: Vuorinen
mesh_terms: D029662:Betula / Q000737:chemistry*; D002241:Carbohydrates / Q000737:chemistry; D002850:Chromatography, Gel; D005052:Eucalyptus / Q000737:chemistry*; D008031:Lignin / Q000737:chemistry*; D008970:Molecular Weight; D014934:Wood / Q000737:chemistry*
chemical_list: D002241:Carbohydrates; D008031:Lignin