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.
Chemical characterization of different mechanical pulp fines
Different mechanical pulp fines were characterized chemically and the role of chemical composition in determining their papermaking properties was evaluated. The chemical composition (surface and bulk lignin, carbohydrates and extractives) of the fines varied widely. There were indications that variations, at least to some extent, were connected to the differences in the physical properties of fines. Correlations between the chemical components of the fines from different processes and sheet properties were not found; conversely in the refining of a TMP pulp, the chemical and physical properties of the fines produced developed simultaneosly, contributing e.g. to sheet strength. It was shown that sheet properties were not determined by any single physical or chemical property of fines alone, but that sheet characteristics are formed by a combination of several factors. It was concluded that the surface content of extractives and hemicelluloses as well as the proportion of the fibrillar material were the most important characteristics contributing to the tensile strength of a fines sheet.
A pilot plant study of alkaline peroxide bleaching of chemimechanical pulps from E. regnans
On compare deux methodes de blanchiment au peroxyde d'hydrogene alcalin (blanchiments PREX et dans le raffineur) appliquees a des pâtes chimicomecaniques d'Eucalyptus regnans. On examine l'energie specifique de raffinage, les proprietes optiques et les proprietes physico-mecaniques des pâtes obtenues.