Investigation on The Effect of Chemical Treatment on The Properties of Chemi-Mechanical Pulp from Rapeseed Stem

The influence of chemical consumption on fiber and strength properties of pulp produced using rapeseed stem is evaluated. Three dosages of NaOH (4, 8, 12%) and four dosages of Na2SO3 (8, 10, 12, 14) were applied and treatment duration and temperature were kept constant as 15 minutes and 125ºC. L/W was 7/1. Screened and total yield of pulps were measured as 57-63% and 60.1-68.95%, respectively. The residual lignin and holocellulose in the pulp varied between 19.75-23.8% and 70.1-73.1%, respectively. The unrefined freeness of the pulps were measured as 330-652 ml CSF which were reduced to 194-301 ml CSF after treatment at 1000 revolution in PFI mill. The fiber classification indicated that the portion of R-100 is amounting to 46.3-53% which did not change after refining. Tensile index was measured as 13.25-15.05 Nm/g which was improved to 14.9-17.79 Nm/g upon refining. However, the tear index was not altered as the pulp was refined and it was remained as 3.07-4.36 mNm2/g. The burst index was fairly low as 1-1.3 kPa.m2/g which after refining increased to 2 kPa.m2/g.