MODIFICATION OF JACK PINE TMP LONG FIBERS BY ALKALINE PEROXIDE – PART 1. CHEMICAL CHARACTERISTICS OF FIBERS AND SPENT LIQUOR
The purpose of this work was to improve the quality of jack pine TMP long fibers, particularly with respect to the strength properties, by alkaline peroxide treatment. This paper reports the chemical characteristics of the treated long fibers and the spent liquors originating from various treatments. It was observed that, in comparison with hydrogen peroxide, the alkalinity of the treatment solutions had a greater influence on most fibre characteristics and spent liquor properties.
Pulp yield loss in alkaline peroxide bleaching of aspen CTMP. Part 1: Estimation and impacts
This study elucidate the relationship between yield loss, brightness, and the development of fiber bonding properties in alkaline peroxide bleaching of aspen CTMP. Peroxide bleaching is a compiex process of simultaneously brightening and strengthening pulps with the inevitable removal of pulp components from the fibers. The dissolution of these substances, which include hemicelluloses, lignin, and extractives, entails a loss in pulp yield and the accumulation of dissolved organic substances in the mill water stream. The strong correlation between yield lose and dissolved organic substances (TOC) makes it possible for us to estimate the bleaching yield by measuring the TOC in bleaching filtrates. Bleaching yield may also be estimated by determining the chemical oxygen demand (COD) or the charge density.
Determination of Charged Groups in Mechanical Pulp Fibres and Their Influence on Pulp Properties
Abstract 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 Norrkopi...