abstract
The present study aimed to evaluate the effect of active alkali charge, in kraft cooking of Eucalyptus globulus wood, on the properties of the laboratory-produced tissue paper. Eucalyptus wood chips were cooked under similar conditions at four different active alkali (AA) levels of 16, 19, 21, and 23 % and DEDED sequence was used for subsequent ECF bleaching. Pulps were analyzed for their intrinsic viscosity, chemical composition, and fiber morphology, while the corresponding papers (20 g/m(2)) were examined for their strength properties, absorptivity, and softness. It was demonstrated that changes in the AA upon cooking, not only affected the chemical composition of the obtained pulps and their intrinsic viscosity, but also the fiber's shape (e.g., curl and kink). These changes caused variations in the properties of laboratory-produced tissue papers. Thus, the increase in AA led to paper with lower tensile strength, but with better softness. Even though the increase of AA in cooking led to bulkier papers, their absorptivity was not significantly enhanced. This was explained, at least in part, by the lower water retention of the pulps obtained from cooking with higher AA.
keywords
PAPER
subject category
Forestry; Materials Science
authors
Henriques, A; Evtuguin, DV
our authors
Dmitry Evtyugin
Associate Professor with Aggregationacknowledgements
This work was carried out under the Project Inpactus-innovative products and technologies from eucalyptus, project no. 21874 funded by Portugal 2020 through European Regional Development Fund (ERDF) in the frame of COMPETE 2020 n 246/AXIS II/2017 and also by the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 & UIDP/50011/2020,financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement.