Comparative study of soda, sodaAQ and monoethanolamine pulps from soybean straw

In this study, the main papermaking characteristics of soybean straw (Glycine max) as an agricultural residue were investigated. The fiber biometry and chemical composition of soybean straw were determined. The properties of pulps from Soda, Soda-AQ and Monoethanolamine (MEA) processes were compared. The average fiber length, fiber diameter, lumen diameter, and cell wall thickness were found to be 1 mm, 26.4 µm, 15.67 µm, and 5.3 µm, respectively. Cellulose, lignin, acetone-soluble extractives and ash content were determined as 41, 19, 4.9, and 3.1%, respectively. Soda, Soda-AQ and MEA pulping under optimum conditions resulted in screened yields of 40.5, 35.5 and 49.5 % respectively. Kappa numbers of corresponded pulps were found out 30, 20 and 20 respectively. The selected pulps were refined up to 300 CSF and mechanical and optical properties of the pulps were evaluated. Maximum burst index (2.65 kpam2/g) and tensile index (54.94 Nm/g) were obtained by soda process. Soda-AQ pulp presents the highest opacity (97%) and MEA pulp shows the maximum tear index (6.52mN.m2/g) and highest brightness (30 % ISO).