polyacrylonitriili

Polyacrylonitrile, also known as PAN, is a synthetic polymer derived from the monomer acrylonitrile. Its repeating unit is -CH2-CH(CN)-, giving a stiff, high-molar-mass material with a high density of nitrile groups along the backbone. PAN is produced by free-radical polymerization in various media, often with small amounts of comonomers to adjust processing or properties. Commercial PAN typically contains a high proportion of acrylonitrile, with controlled molecular weight and distribution.

PAN can be processed into fibers, films, and molded articles. In fiber form, PAN is usually spun from a polymer solution or latex and then drawn to increase strength. The polymer is relatively stiff and thermally stable, but it has limited solubility in common solvents; it dissolves in select solvents such as certain nitrile-containing or high-boiling solvents at elevated temperatures, and is more easily handled in solution or latex form for spinning.

A major use of PAN is as a precursor for carbon fibers. PAN fibers undergo stabilization (cyclization) in air at elevated temperatures, typically around 200–300°C, followed by carbonization at higher temperatures (often 1000–1500°C) in inert environments. This conversion yields carbon fibers with high tensile strength and stiffness, used in aerospace, automotive, and sporting goods applications. PAN chemistry also supports copolymerization and modifications to tailor spinning, stabilization, and carbonization behavior.

Health and safety considerations center on the acrylonitrile monomer, which is toxic and potentially carcinogenic. The polymer itself is generally less hazardous, but residual monomer and processing conditions require appropriate controls.