Investigation on the Influence of Alkaline Pre-Extraction of Barley Straw on Soda and Monoethanolamine Pulps Properties

In this study, the alkaline pre-extraction followed with soda and monoethanolamine pulping of barley straw was investigated. The pre-extraction stage with removal of 34percent hemicelluloses due to highest yield was selected as optimum treatment. The results of pulping show that pre-extraction stage resulted in decrease of yield in both pulping processes meanwhile only in soda process the kappa number was influenced with pre-extraction stage. Tensile and burst indices of pulps drop because of pre-extraction stage. Unlike of these indices, the tear index of soda pulp from pre-extracted barley straw has been increased. The brightness of soda pulp from pre-extracted barley straw is increased while the pre-extraction stage has no significant effect on brightness of monoethanolamine pulps. The opacity of pulps remains unchanged after pre-extraction.