Modification of softwood kraft pulp fibres using hydrogen peroxide at acidic conditions
Journal article, 2020

The aim of this work was to provide softwood kraft pulp fibres with new functionalities by the introduction of carbonyl groups. Carbonyl groups are known to affect properties such as wet strength through the formation of covalent bonds, i.e. hemiacetals. The method developed involves oxidation using hydrogen peroxide at mildly acidic conditions. It was found that the carbonyl group content increased with both increasing temperature and residence time when oxidized at acidic conditions. The number of carboxylic groups, however, remained approximately constant. There was virtually no increase in carbonyl groups when oxidation was performed at alkaline conditions. The maximum increase in carbonyl groups was found at a residence time of 90 min, a reaction temperature of 85 °C and a pH of 4. These conditions resulted in an increase in carbonyl groups from 30 to 122 µmol/g. When formed into a sheet, the pulp oxidized at acidic conditions proved to maintain its structural integrity at aqueous conditions. This indicates the formation of hemiacetal bonds between the introduced carbonyl groups and the hydroxyl groups on the carbohydrate chains. Thus, a possible application for the method could be fibre modification during the final bleaching stage of softwood kraft pulp, where the wet strength of the pulp could be increased.

Bleaching

Hydrogen peroxide

Wet strength

Carbonyl groups

Cellulose oxidation

Author

Axel Martinsson

Chalmers, Chemistry and Chemical Engineering, Chemical Technology, Chemical Reaction Engineering

Merima Hasani

Chalmers, Chemistry and Chemical Engineering, Chemical Technology, Chemical Reaction Engineering

Wallenberg Wood Science Center (WWSC)

A. Potthast

University of Natural Resources and Life Sciences, Vienna

Hans Theliander

Chalmers, Chemistry and Chemical Engineering, Chemical Technology, Chemical Reaction Engineering

Wallenberg Wood Science Center (WWSC)

Cellulose

0969-0239 (ISSN)

Vol. In Press

Subject Categories

Paper, Pulp and Fiber Technology

Polymer Technologies

Organic Chemistry

DOI

10.1007/s10570-020-03245-z

More information

Latest update

6/3/2020 6