HIGHLY SUBSTITUTED CATIONIC STARCH AS AN ANIONIC TRASH CATCHER FOR HIGH YIELD PULP CONTAINING FURNISH

摘要

High yield pulp and recycled fibers have found their increased application in papermaking process. There could be a build-up of anionic trash in the system. Traditionally, anionic trash catchers (ATCs), such as PEI and poly-DADMAC, are used to minimize this problem. In this work, an alternative ATC, highly substituted cationic starch (HS-CS), was developed for the same purpose. The efficiency of HS-CS with different DS 0.57-0.97 was determined in DCScontaining furnish and the optimized condition for filler retention was studied when HS-CS was used in the microparticle retention system (CPAM/bentonite). Furthermore, the dynamic flocculation behavior was demonstrated in a dynamic drainage jar (DDJ) equipped with photometric dispersion analyzer (PDA). The results show that HS-CS is a very good ATC. With the addition of HS-CS, the negative effects of DCS on the microparticle retention system can be eliminated and the effectiveness of retention aids can be improved. The results from the dynamic flocculation experiments of DCS-containing furnish support the same conclusion.