Study on the High Charge Density Polyamine System in Controlling Dissolved and Colloidal Substances of High-Yield Pulp

Abstract

In recent years High yield pulp (HYP) is being used at an increasing rate to replace bleached hardwood kraft pulp in the manufacturing of high quality paper products. However, HYP has more dissolved and colloidal substances (DCS), when compared with fully bleached kraft pulp. In general these DCS have an anionic character, and they often disturb the papermaking process. In the paper, the effects of high charge density polyamine (PA) single, dual and triple system on DCS control in high yield pulp were studied. The results showed that the DCS control effects of the PA/HCS (high cationic starch)/CPAM (cationic polyacrylamide) triple system were better than the PA/HCS dual system and the PA single system. In the PA/HCS/CPAM triple system, when the dosage of the PA was 0.06% and the dosage was 0.1% and 0.05% for HCS and CPAM, respectively, the zeta potential of pulp increased by a certain degree, drainage property of pulp improved remarkably, the turbidity of the DCS water was near to zero, and the cationic demand of DCS water decreased by 70.8%. The microscope photograph of fibers also confirmed that the polymers in the PA/HCS/CPAM triple system had very good synergetic effects on the removal of DCS in high yield pulp.