WOOD RESEARCH Volume 70, Number 2, 2025
GANIS LUKMANDARU, MUHAMMAD AKBAR FAQIH, and SIGIT SUNARTA

PULPING AND PAPERMAKING POTENTIAL OF ACACIA AULACOCARPA BENTH WOOD IN INDONESIA

In this study, samples from 27-year-old Acacia aulacocarpa grown on a plantation were examined to determine suitable kraft pulping conditions and properties for paper production. The results showed that A. aulacocarpa had a high basic density of 0.65 g/cm3 and a short fiber length of 0.84 mm. The derived values for Runkel, slenderness, and flexibility ratios were 1.02, 53.01, and 0.48, respectively. Five different active alkali concentrations ranging from 14% to 22%, with intervals of 2% were applied for kraft cooking. The percentages of reject, kappa number, and residual active alkali of black liquor were negatively related to the charge applied in pulping runs. Pulping with 18% active alkali content obtained a screened yield of 51.4% at a kappa number of 34.1. The 20% active alkali cook had the highest mechanical properties of the handsheets. The burst and tear indices met the Indonesian National Standard for leaf (hardwood) bleached kraft

WOOD RESEARCH Volume 64, Number 6, 2019
Vladimír Mašura, Balberčák Jozef, Kuňa Vladimír, and Radoslav Mikulášik

Reaction phases of the wood constituents’ degradation during kraft cooking of spruce chips

In this study, the changes of the individual constituents of wood, mainly lignin fraction, and carbohydrate fraction of partially delignified wood chips were investigated. The concentration of alkali during kraft cooking of spruce chips were characterized with respect to the time of kraft cooking, consumed alkali and also to the time-temperature variable (H-factor). The observation brought a new fact, that the extraction of lignin and degradation of the carbohydrate fraction as well as the wood residue itself, were realized in two different reaction phases: initial and residual. The power form dependences between the studied constituents of the wood during kraft cooking were interpreted in a logarithmic coordinate system by the straight line relationship.