Effect of Cationic Starch and Chitosan on Dry Strength of Bleached Soda Pulps Made of Pre-Extracted and Non-Extracted Bagasse

Abstract

This study focused on the properties of alkaline pulp obtained from the soda pulping of pre-extracted bagasse and the effects of dry strength polymers on mechanical properties of paper in comparison to a paper obtained from nonextracted bagasse. Hot-water pre-extraction was carried out at 135°C for 30 min. Consequently, soda pulping and ECF bleaching were performed on pre-extracted and un-extracted bagasse, under similar conditions. It was found that pre-extraction of about 50% of hemicelloluse of the bagasse decreased total pulping yield, kappa number and increased bleachability of pulps and resulted in a significant loss in tensile and burst strengths of hand-sheets. Then, reinforcing effect of the pulps with chitosan and cationic starch applied in the wet-end were investigated. The results obtained with suitable amounts of chitosan and cationic starch were encouraging, because comparable strengths were obtained from pre-extracted and un-extracted bleached soda bagasse pulps with 1% chitosan and 1.5% cationic starch. According to the results, drop in paper strength due to hemicellulose pre-extraction of the bagasse could be compensated using suitable dry strength polymer. E     Effect of Cationic Starch and Chitosan on Dry   Strength of Bleached Soda Pulps Made of   Pre-Extracted and Non-Extracted Bagasse   Zeinab Khorasani 1, Yahya Hamzeh1*, Alireza Ashori2, and Mohammad Azadfallah 1   1. Faculty of Natural Resources, Department of Wood and Paper Sciences and Technology, University of Tehran, P.O. Box: 31585-4314, Karaj, Iran 2. Department of Chemical Technologies, Iranian Research Organization for Science and Technology (IROST), P.O. Box: 15815-3538, Tehran, Iran Received 2 April 2012, accepted 17 December 201