Abstract: The effects of different beating levels on drainability and fiber morphologies of rice straw alkali-oxygen pulps were investigated by PFI mill, and the strength performances of hand-sheets prepared by this pulp were also analyzed. The results showed that the changes of the beating degree and water-retention value were similar in the initial stage and later stage of beating. In the initial stage, the beating degree was rapidly increased to 55-60°SR. Meanwhile, the water-retention value was increased to about 45°SR. When the beating degree was increased to 75°SR from 35°SR, the fiber length changed little with the maximum decrease rate of the pulp without non-fibrous cells (P_nof) of 7.3% and that of the pulp with non-fibrous cells (P_f) of 4%, and more fibrillated fibers were observed during the beating process. The non-fibrous cells played negative roles on both the improvement of pulp drainabilityand the strength properties. The best burst index and tensile index were obtained as the beating degree was 65°SR. In addition, an ever-increasing tendency was found in terms of burst index and tensile index of paper sheets of P_nof with higher beating degree(above 65°SR).

Key words: rice straw alkali-oxygen pulp, non-fibrous cells, beating, strength properties, drainability