In the present study, morphological characteristics and chemical composition of the two raw materials (kenaf and bagasse) were investigated. The optimum conditions for their cooking were also determined. Bagasse had the highest cellulose content (51%) with low lignin (17%) compared to cellulose and lignin contents for kenaf core (42.0) and (25.0), respectively. With regards to anatomical characteristics, the lumen diameter and cell wall thickness for bagasse were 10.91 ?m and 7.37?m and for kenafbast were 7.75 ?m and 2.33 ?m, respectively. Runkle ratio for kenafbast was 0.31 which was lower than bagasse (0.62). Cell coefficient of rigidity was0.62 for bagasse and (0.77 for kenafbast). Longer fibers with lower cell wall thickness showed significant advantages in strength properties of the produced paper like the case of paper produced from kenafbast. Pulp yields for the studied materials were 49 and 49.5% for Kenafbast and, 43%-44% for kenaf core with 16% and 17% active alkali respectively. The increase in alkali charges lowered the screened yield from 49.9% to 45% and kappa number from 21 to 18forbagasse using active alkali charge of12% and 13% respectively. Bagasse also gave acceptable yield and kappa number. As for paper properties.the burst index for paper produced from bagasse cooked at 12% active alkali increased from 0.80 to 2.6 kpa m/g with beating time. The tensile index on the other hand, increased from 31.0 to 75.7 Nm/g with increased beating time, while bulk density increased from 5.88 to 9.31 g/cm?. When bagasse was cooked with 13% active alkali the burst index increased from 0.70 to 2.9 kpa m/g with beating time, while tensile index increased from 51.4 to 78.0 Nm/g. The bulk density also increased with beating time from 5.88 to 9.97 g/cm. The brightness was 37%. This indicated that all properties were significantly improved by increasing beating time and using higher active alkali percentage. When kenaf bast was cooked with 17% active alkali, the tensile index of the paper produced decreased from 105 to 79 Nm/g with beating time, while burst index increased first from 4.8 to 5.7 and then decreased to5.1 kpa*m/g with beating time. The decrease in these properties with beating time is due to the breaking of the long fibers of kenaf bast with beating. Kenaf core was cooked with 16% and 17% active alkali. The tensile index of paper in case of 16% active alkali increased from 23.5 to 45.7 Nm/g with increased beating time, while burst index increased from 0,50 to 1.5 kpa*m/g.

: Soda pulping

fiber characteristic

papermaking