Polyacrylamides

Polyacrylamides (PAM) are synthetic polymers derived from acrylamide units. They are typically water-soluble and can be prepared as linear polymers or lightly crosslinked networks. By controlling the degree of hydrolysis, PAM can be nonionic, anionic, or cationic, with the charge density affecting conformation, solubility, and application performance.

Polyacrylamides are produced mainly by free-radical polymerization of acrylamide in aqueous solution. The process can yield high-molecular-weight polymers suitable for use as thickening and flocculation agents. Partial hydrolysis converts some amide groups to carboxyl groups, creating anionic PAM; specialized formulations can be cationic to target negatively charged particles.

Key properties include high molecular weight, water solubility, and the ability to form viscoelastic solutions. Crosslinked PAM, achieved with crosslinkers such as N,N'-methylenebisacrylamide, forms gels used in chromatography and electrophoresis; non-crosslinked PAMs are common as additives in industrial processes.

Applications are broad. In water treatment, PAMs act as flocculants and retention aids to aggregate solids for removal. In papermaking, they improve retention and drainage. In agriculture, hydrolyzed PAMs improve soil water retention and structure. In oil and gas, they are used as polymer flooding agents to increase viscosity and sweep efficiency.

Safety and environmental considerations focus on residual acrylamide monomer, which is a neurotoxin and potential carcinogen. Manufacturing and formulation aim to minimize residual monomer, and PAMs are used with regulatory controls to manage exposure and environmental impact.