Effect of Boiling Water Pre-Treatment on Yield and Physical, Optical and Mechanical Properties of Neutral Sulfite Semi Chemical Pulp of Wheat Straw

In this study the effect of boiling water pretreatment on yield and optical, physical and mechanical properties of NSSC (Neutral Sulfite Semi Chemical) pulp of Golestan province wheat straw was investigated. Splinted wheat straw was pretreated with the boiling water (100 degrees) in the 10:1 ratio for 30 minutes. NSSC pulping carried out at constant condition including liquor to straw 10:1, maximum temperature 160ºC for 30 minutes. In order to study the effect of NaOH on strength properties of paper in some cases only Na2S03 were used. After pulping defibration was done by laboratory refiner to achieve 380±25ml (CSF). Hand sheets from each pulp with 60 gr/m² were made. The strength properties determined on the basis of TAPPI standard. Results show that pretreatment have a desirable effect on increasing the strength properties of papers such as and tensile, burst, breaking length, stiffness and density, except RCT strength other strengths of paper increase. Measuring the freeness of pulps showed that by increasing chemical contents specially NaOH freeness, yield, thichness and bulk decreased and density increased.