Synergetic Effect of Cationic Polymers on Water Repellency of Cellulosic Fiber Network Paper Filled with Waste Lime Sludge.

Lime sludge is commonly generated from the pulping waste liquor in alkali recovery of paper industry. It would cause a significant decrease in the alkyl ketene dimer (AKD) sizing efficiency as used to be the filler for cellulosic fiber networks paper. In the present work, Polyamide-Polyamine-Epichlorohydrin (PAE), Polyetherimide (PEI) and chitosan were used as sizing promoters for addressing the above issue. Results showed that the sizing degree of paper filled with 26% lime sludge could be increased by 83.4%, 68.9% and 49.7%, respectively, at the optimal dosage of PAE, PEI and chitosan. Curing time and curing temperature also had significant impacts on the efficiency of the three sizing promoters. All the three sizing promoters could remove the anionic trash in the wet end. Moreover, PAE could promote the reaction between AKD particles and cellulosic fibers. [ABSTRACT FROM AUTHOR]