Polycarboxylate

Polycarboxylate is a class of polymers that contain multiple carboxylate groups (COO−) within the chain or as pendant units. The repeating carboxylate groups render these polymers anionic in neutral or basic conditions and confer strong hydrophilicity, enabling solubility in water and interactions with metal ions.

The term encompasses polyacrylates and their salts, polymaleates, and related copolymers, as well as specialized polycarboxylate ethers used as concrete superplasticizers. In many materials, carboxylate groups are derived from acrylic or methacrylic acids, or from hydrolyzed esters of such acids.

Structures vary from long chain polyacrylates with pendant carboxylate groups to random or block copolymers that include nonionic blocks. The polymers are commonly prepared by free radical polymerization of acrylic acid or its derivatives, followed by neutralization to sodium, ammonium, or other metal salts. Some formulations employ ether linkages to form polycarboxylate ethers, which are widely used as dispersants.

Applications are diverse. They include dispersants and stabilizers in cementitious systems (notably polycarboxylate ether superplasticizers), water treatment and detergent formulations, paper and textile auxiliaries, and cosmetic thickening agents. Their ability to bind multivalent cations and to impart steric hindrance underpins many of these uses.

Environmental and safety considerations vary by structure and molecular weight. Some polycarboxylates are not readily biodegradable, while modified forms are designed for improved environmental performance. Product-specific regulatory data and handling guidelines should be consulted for particular materials and applications.