Acrylamide-Based Anionic Polyelectrolytes and Their Applications: A Survey

摘要

Water-soluble polymers are found in a very broad range of industrial applications. An important class of these is acrylamide-based polymers which bear negative charges along the polymer chain and are called anionic polyelectrolytes. These negatively charged polymers are widely used as flocculants, rheology control agents, and adhesives. They are employed especially in oil field operations as viscosity control agents for enhanced oil recovery and to a lesser degree in engineering fluids used for lubrication, for effluent reclaiming, and for opening oil passage channels in oil-bearing rock. Paper manufacture, mining, and water treatment processes also benefit from the use of acrylamide-based polymers to flocculate solids in aqueous dispersions. The acrylamide-based polymers are made by the free-radical polymerization of acrylamide and its derivatives via bulk, solution, precipitation, suspension, emulsion, and copolymerization techniques. Among these, solution polymerization is a preferred technique because of difficulty with temperature and agitation control in bulk polymerization and the cost of surfactants and solvents for suspension, emulsion, and precipitation polymerization. The anionic polymers may interact with particles in aqueous dispersions in several ways that result in the stability or instability of the dispersions. The particles in solid-liquid phases can be destabilized through three main mechanisms which promote flocculation and cause destabilization. These mechanisms are polymer bridging, charge neutralization, and polymer adsorption. The particles in solid-liquid phases can be stabilized by the anionic polymers through both electrostatic and steric repulsive forces.