EFFECT OF EXTRACTIVE REMOVAL ON KRAFT PULP PROPERTIES OF ACACIA AULACOCARPA WOOD

Abstract

Acacia aulacocarpa A.Cunn. ex Benth is considered a potential source of fiber for the pulping and paper-making industries. This study aimed to evaluate the properties of Acacia aulacocarpa kraft pulp in relation to the presence of extractive. A separate assessment was conducted on the chemical composition and pulp properties of the sapwood and heartwood. Extractive removal was achieved with various organic solvents including n-hexane, ethanol, and hot water in successive steps. The results showed that heartwood and sapwood had different chemical characteristics affecting pulping outcomes. The total extractive content of heartwood (12.45%) was substantially higher than in sapwood (3.62%) with ethanol soluble being the major fraction ranging from 69% to 86%. Without extractive removal, only slight differences were found in the screened yield, kappa number, viscosity, as well as redness and yellowness values of pulps. Heartwood pulps had more hexeneuronic acid content and were darker than sapwood pulps. After extractive removal, substantial differences were found in screened yield, hexeneuronic acid content, and brightness. The sapwood part showed a considerable increase in screened yield (38.21% to 45.93%) than heartwood (37.21% to 40.92%). This suggested that components of sapwood extractive might inhi bit delignification during pulping.