Comparing the effect of alkali charge and treatment time on the properties of bagasse and eastern cottonwood cold soda pulp

Abstract

The purpose of this study was to compare the effects of various concentrations of sodium hydroxide and treatment times on the properties of bagasse and Eastern cottonwood (Populus deltoids) cold soda pulp and paper. The cold soda pulp was prepared using various concentrations of sodium hydroxide (5, 10, 15% based on oven dry weight), different treatment times (20, 40, 60 min.), and constant liquor to wood ratio of 10:1 at 25 ºC and atmospheric pressure. The pulp prepared after 40 min treatment time was selected and refined to the freeness of 400 ml CSF. Analysis of the properties of hand sheets was conducted based on completely randomized design. Duncan multiple range grouping test was used to classify the properties of papers. The results indicated that, the yield of pulp obtained from Eastern cottonwoodand bagasse pulp varied between 86.54% to 94.52% and 70.65 to 87.32% respectively. The absorbed alkali was varied from 2.15% to 4.78 % for Eastern cottonwood and 3.06% to 6.80% for bagasse. Eastern cottonwood had the highest yield, thickness and strength properties whereas the highest absorbed alkali and paper density were observed in bagasse. It was observed that as the concentration of sodium hydroxide was increased from 5% to 15%, the yield of pulp and the thickness of paper decreased, while the absorbed alkali, density and the strength properties of paper increased. In general, the cold soda pulp from Eastern cottonwood provided higher quality compared with bagasse under the same pulping conditions.

Keywords

• Cold soda pulp
• Bagasse
• eastern cottonwood
• populus deltoids
• yield
• alkali absorption
• Strength properties