Polyacrylamide

Polyacrylamide is a water-soluble polymer composed of repeating acrylamide units. It is produced by free-radical polymerization of acrylamide or by partial hydrolysis of polyacrylamide to introduce carboxyl groups, yielding anionic, cationic, or nonionic forms. The degree of hydrolysis and the polymer architecture (linear or crosslinked) determine charge density, solubility, and performance. Commercial polyacrylamides are available as nonionic, anionic, cationic, or amphoteric products, with molecular weights ranging from several million to tens of millions of daltons. Crosslinked variants are used to form gels, notably in laboratory and industrial applications.

Applications of polyacrylamide span water treatment, paper production, mining, and oil recovery. As flocculants and thickening agents, PAMs promote aggregation of particles and improve solid–liquid separation in municipal and industrial wastewater treatment, as well as in sludge dewatering. In the paper industry, they aid retention, drainage, and formation of paper sheets. In mining and mineral processing, PAMs assist flotation and solids handling. In enhanced oil recovery, high-molecular-weight, partially hydrolyzed anionic PAMs increase injected-water viscosity and reduce permeability losses, aiding sweep efficiency. PAMs are also used in soil stabilization, agriculture, cosmetics, and as gel matrices for electrophoresis.

Safety and regulation: residual acrylamide monomer is a health concern, leading to strict manufacturing and handling controls to minimize free monomer content. PAM itself is generally regarded as a relatively inert polymer, but inappropriate use or environmental release at high concentrations can pose risks. Practices and limits are governed by national and international regulations.