Investigation on Properties of Soda and Soda/AQ Pulps from Corn Stalk

Soda and soda-AQ pulping of corn stalk applying different charges of active alkali and pulping time was studied. The average value of fiber length, diameter and cell wall thickness were measured as 1.03 mm, 23.64 µm and 5.26 µm, respectively. The content of alcohol-acetone extractives, cellulose, lignin, extractives soluble in 1% NaOH and ash content of corn stalk were determined as 15%, 51.2%, 23%, 45.95% and 2%, respectively. Pulping with four levels of sodium hydroxide (12, 14, 16 and 18%, based on NaOH), and two cooking times (15 and 30 minutes) and constant cooking temperature at 145 ºC was performed. 0.1% AQ was added to soda/AQ cooking liquor. After analyzing the pulping yield and kappa number, two pulps were selected (NaOH; 12, 18%, cooking time; 15 minutes and cooking temperature; 145 ºC) as brown and bleachable stock, respectively. Eventhougth addition of 0.1% AQ showed no significant effect on pulping yield, but its effect on paper strength properties was significant. The result of handsheet evaluation revealed that the strength of pulp produced applying 18% NaOH, 0.1% AQ, and 15 minutes pulping time with breaking length of 8.21 km, and 80.59 N.m/g tensile index was superior to other pulping conditions. The tear index of the pulp produced applying 12% NaOH, 0.1% AQ and 15 minutes pulping time was determined as 10.60 mNm2/g. The burst index of pulp produced using 18% NaOH, 15 minutes pulping time without AQ addition, was the highest.