The effect of electerical conductivity on the performance and interaction of cationic starch- anionic nanosilica in pulp slurry

As the papermaking fibers contain negative charge, therefore some polymer additives used in the pulp slurry, possess counter-ions (cationic polyeletrolyte). Meanwhile, due to increase of electrical conductivity (EC) in the suspension, the performance of many polyelectrolytes encounter some problems. Hence, according to the efforts for the water system closure, less raw water consumption, and therefore higher EC of the pulp suspension, how the performance of polyelectrolyte-based additives such as cationic starch-anionic nanosilica is adversely affected. In this due, the effectiveness of EC on the performance of the mentioned additive combination was investigated. The results confirmed that the EC negatively affected the performance of the wet-end additive system; although the amount of effectiveness was dependent on the type of the pulp property. Such that for low polyelectrolyte dosage and high EC, in certain properties, the positive effect of this additive system was not significant anymore. But, in the case of some other properties such as internal bond and freeness, despite of the negative effects of high EC, the performance of cationic starch-anionic nanosilica system was significantly remarkable.