Abstract:
Due to the shortage in forest based raw materials for paper, the possibility of alternative cellulosic fibrous raw materials have been explored. Among these Kenaf and bagasse draw the attention as promising nonwood fibrous materials. In the present study, fiber characteristics and chemical composition were investigated for the to raw materials. The optimum conditions for their cooking were determined and their blending potentiality was examined. Bagasse has shown the higher cellulose content (51%) with low lignin (17%) while cellulose and lignin contents for kenaf core were (42.0) and (25.0) respectively. The higher ash content was observed in bagasse 3.0%, while kenaf core has shown the lower ash content(2.9%).with regards to fiber characteristics The lumen diameter and double cell wall thickness for bagasse were (10.19 and 7.37µm) and; kenaf bast were (7.75, 2.33 respectively). It was found that the Lumen width affects the beating of the pulp. The Runkle ratio for kenaf bast was (0.31µm) which was lower than bagasse (0.62µm), low Runkle ratio gave higher paper strength, the coefficient of cell rigidity was (0.91µm) for bagasse and kenaf bast for (0.11µm), Pulp yields for the studied materials were 49 and 49.5% for kenaf bast and, 43%-44% for kenaf core 17% and 16%active alkali respectively. The increase in alkali charges has lowered the screened yield from 49.9% to 45% and kappa number from 21 to 18 for bagasse using active alkali charge of 12% and 13% respectively. Bagasse gave acceptable yield and kappa number. Mixtures (50:50 and 70:30) of kenaf core to bast were cooked with 16% active alkali charge to produce the same yield (42%).With regards to paper properties. the burst index for bagasse, at active alkali (12%, 13%) was found to be 2.6kpa*m/g and (2.9kpa*m/g) respectively. Bulk density was 15.41g/cm3 but increased with beating time. Tensile index for Bagasse using active alkali (12%, 13%) was (31and 15.4Nm/g) and increased with beating time to 62 and 78 Nm/g.The bast fiber showed higher tensile index compared to commercial pulp woods(105Nm/g) without beating. The mixture of kenaf bast and kenaf core by ratio (50:50) active alkali (16%) gave tensile index of (61.6Nm/g) and burst index of (1.3kpa*m/g), while burst/core mixture of (70:30) gave tensile index 75.9 and burst index (4 kpa*m/g).Longer fiber with lower cell wall thickness showed significant advantages in physical properties of the produced paper.
