Mini-Encyclopedia of Papermaking Wet-End Chemistry
Part Two: Definitions and Concepts

Microparticle Effect

The microparticle effect consists of a strong increase in drainage rates when a papermaking furnish is treated with anionic colloidal substances such as colloidal silica, bentonite, or certain highly branched anionic polymers. The effect is observed only if the furnish has been pretreated with (a) a sufficient level of cationic additives so that the furnish has a near-neutral or positive zeta potential, (b) a sufficient level of very-high-mass polymer such as cationic polyacrylamide or cationic starch, and (c) hydrodynamic shear to reduce the level of fiber-to-fiber flocculation.

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This page is maintained by Martin hubbe, Associate Professor of Wood and Paper Science, NC State University, m_hubbe@ncsu.edu .