Abstract
Iran is facing a severe lack of fibrous raw materials for paper production. Kenaf (Hibiscus cannubinus L.) is a superior complement to wood as a source of fiber. Kenaf bast fibers are excellent for making pulp and paper of various grades due to the presence of high alpha cellulose (56.43), holocellulose (77.71), and ultimate fiber length (2.77 mm). Fiber length is an important factor in the development of tear and tensile properties. The aim of this work is to study the effect of charge alkali (20 and 25% oven dried, as NaOH) and cooking time (30, 60, 90, 120, 150, and 180 min) of kenaf bast fiber on soda and soda-anthraquinone (AQ) pulp yield, kappa number, rejects, and strength properties of their handsheets. Results indicated that alkali charge and cooking time had significant influence on kappa number, yield, and rejects of pulps, whereas PFI revolution had only a minimal effect, especially at higher cooking times. The soda method was modified by adding 0.2% anthraquinone, and the resultant pulps displayed an increase in pulp yield and reduction in both kappa number (by 6 to 9 units) and screening rejects. The strength properties obtained with the two cooking processes used were compared, and those provided by soda-AQ process were found to be best. Regarding handsheet properties, a significant improvement in tensile index could be obtained by the soda-AQ process, compared to the soda process.Download PDF