Flocculation of polystyrene particles with cationic polyelectrolytes

Abstract

Monodisperse polystyrene particles, with surface carboxyl groups, have been prepared by emulsion polymerization. These have been used in flocculation studies with two commercially available cationic polyelectrolytes, one of low and the other of high molecular weight. Surface charge density of the particles was reduced by lowering pH, and increased by adding anionic surfactant. The effect of these changes on the flocculation behaviour has been investigated. The results, together with electrophoretic data, indicate that polymer bridging is a significant mechanism for the high-molecular weight flocculant, but that the low-molecular-weight polymer is effective mainly as a result of charge neutralization.