Volume 54 (2000) Issue 7 Pages 969-976,018
Kenaf basts with brown and green epidermis (Hibiscus cannabinis) were subjected to alkaline oxygen pulping to fill up a deficiency of softwood kraft pulp in future. Fifteen % NaOH of bast was necessary for the brown epidermis to decolorize during the pulping. However, the latter yielded crude pulp without colored epidermis by the pulping with 8-15% NaOH at 7kg/cm2 and 110°C for 1h. The crude pulps with kappa numbers of 44-54 in yields of 67-78% based on bast gave oxygen pulps with kappa numbers of 21-31 in yields of 56-59% based on bast when refluxed with 50-70% aqueous AcOH for 1 h. The oxygen pulps were full-bleached by sequence of 5% Pa-1% P-1% Pa-1% P and so forth. Strength properties of the oxygen pulp and full-bleached pulp obtained from both of the bast were compared to the properties of unbleached and bleached kraft pulps of softwood.