Highly Substituted Cationic Starch as an Anionic Trash Catcher for High-Yield Pulp

Abstract

High-yield pulp (HYP) and recycled fibers containing anionic trash are being used increasingly in the manufacture of various paper grades. Traditionally, anionic trash catchers (ATCs), such as PEI, CPAM, and poly-DADMAC, are used to minimize the anionic trash problem. In this work, we studied an alternative ATC, highly substi-tuted cationic starch (HS-CS). We determined the efficiency of HS-CS with different degrees of substitution of 0.57-0.97 in furnish containing dissolved colloidal substances (DCS). Flocculation behavior was also demonstrated in a dynamic drainage jar (DDJ). The results showed that HS-CS is a very good ATC. With the addition of HS-CS, the neg-ative effects of DCS on the microparticle retention system can be minimized and the effectiveness of retention aids can be improved. The results from the dynamic flocculation experiments support the same conclusion.