Flocculation Effect of Macromolecule

Abstract

Citation: Chang Q. Flocculation Effect of Macromolecule. Polym Sci. 2016, 2:1. In the early years, it was found that colloidal dispersions can be made more sensitive to precipitation by the addition of small quantities of macromolecules. These macromolecules are referred to as flocculants currently. The macromolecular flocculants commonly used in early time are polyelectrolytes. Their flocculation mechanism is considered to be the simple charge neutralization. If the charges of macromolecular ions are opposite to that of particles, flocculation and precipitation will take place. But in the later period, it has been discovered that some non-ionic macromolecules, even the macromolecules with the same charge as the colloidal particle have sensitive or flocculation effect. Therefore, neutralization is not the only mechanism of their flocculation. Now we think long-chain additives, such as gelatin, can sometimes bring about a rather loose flocculation by a bridging mechanism in which the molecules are adsorbed with part of their chain on two or more particles. Such flocculation normally occurs over a narrow range of additive concentrations; at higher concentration protective action is obtained, since bridging can occur only under conditions where the remaining particles still have empty surface, thus further adsorption of the additive is possible.