Comparative alkaline pulping of two bamboo species from Sudan

Two potential bamboo species (Oxytenanthera abyssinica and Bambusa vulgaris) growing in Sudan were examined as to their suitability for pulping and papermaking, by different alkaline pulping methods. Their physical, morphological and chemical characteristics are reported. The pulping trials were carried out by kraft-AQ, soda, soda-AQ, alkaline sulphite-AQ (AS/AQ) and ASAM methods, as well as by the kraft method - taken as a reference; ASAM pulping gave the best results as to the yield, degree of delignification, mechanical and optical pulp properties. The best Oxytenanthera abyssinica pulps obtained gave, within a totally chlorine free bleaching sequence (OQ₁O/PQ ₂P), bleached pulps of 82% ISO brightness, suitable for writing and printing paper grades. The different fibre morphology and chemical composition of the two bamboos were reflected in their response to pulping and in the pulp properties. The Oxytenanthera abyssinica pulps were similar to hardwood kraft pulp, while the Bambusa vulgaris ones, with extremely high tear strength, were close to softwood kraft pulps, which recommends them as a welcome substitute for coniferous wood and for use, either alone or in blends, in flexible packaging paper grades.