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This study investigates the operating conditions used in the sodaanthraquinone pulping of Eucalyptus globulus wood after autohydrolysis pretreatment on the yield, kappa number, and brightness of the resulting unbleached pulp. Moreover, strength-related properties of the resulting handsheets was examined to identify the best pulping conditions and compare the outcome with that of a conventional soda-anthraquinone pulping process. The paper strength properties of the pulp were similar to or better than papers made from soda-AQ delignified pulps conducted in a single step. Also, a liquid fraction with a substantial content in hemicellulosic extracts was recovered in the simplified process. Autohydrolysis of the raw material facilitates carrying out soda-AQ pulping under milder conditions. In addition, autohydrolysis improves other properties relative to paper from raw cellulose pulp. Yield, kappa number, and brightness for pulp from solid residues of autohydrolysed eucalyptus wood were similar to those for pulp from untreated eucalyptus wood. [ABSTRACT FROM AUTHOR]

Cationizations of galactomannan- and xylan-type hemicelluloses were performed in a solid state, with 2,3-epoxypropyltrimethylammonium chloride (ETA) as the cationic reagent under alkaline conditions. By this method, the reaction efficiency was significantly increased for all hemicellulose types, up to 90% in the case of xylan. The consumption of reagents was reduced by a factor of ten when compared to the reaction in liquid phase, while comparable values of the degree of substitution (DS) were obtained. By reducing the number of purification steps, the consumption of solvents was limited, and high mass yields were preserved. By all aspects, this method constitutes an economical and environmental gain for the cationization reaction of hemicelluloses. Native hemicelluloses and their cationic derivatives were tested as additives to the pulp slurry in order to increase the dry strength of the paper formed. The cationization of hemicelluloses had a beneficial effect on the mechanical properties of paper, with a supplementary gain of properties compared to the unmodified polysaccharides. Cationic derivatives of a DS 0.3 gave the best results for both polysaccharides, with the galactomannan-type being more efficient than the xylan-type with a 90% increase of the burst index. [ABSTRACT FROM AUTHOR]