Determination of Charged Groups in Mechanical Pulp Fibres and Their Influence on Pulp Properties

The content of charged groups, i.e carboxylic and sulfonic acid groups in various kinds of mechanical pulp fibres has been investigated. Special emphasis has been given to the determination of the charged groups located at the fibre surfaces using a polyelectrolyte titration technique. The significance of these charged groups for some physical properties of the pulps has also been evaluated. The results suggest that it is feasible to determine the surface charges of the various kinds of mechanical pulp fibres by applying the polyelectrolyte titration technique. This study also indicates that fibre surface charges can serve as one of the basic chemical parameters to characterise fibre Surface properties, and that both total charged groups and surface charged groups are important for the physical properties of the pulps. 1Present address: Royal Institute of Technology, Department of Wood Chemistry, S-100 44 Stockholm, Sweden. 2Present address: Holmen Paper AB, Braviken Paper Mill, S-601 88 Norrköping, Sweden.