Acrylic fibers are synthetic fibers made from a polymer (Polyacrylonitrile) with an average molecular weight of ~100,000. To be called acrylic in the U.S., the polymer must contain at least 85% acrylonitrile monomer. Typical comonomers are vinyl acetate or methyl acrylate.
The polymer is formed by free radical polymerization. The fiber is produced by dissolving the polymer in a solvent such as N,N-dimethylformamide or aqueous sodium thiocyanate, metering it through a multi-hole spinnerette and coagulating the resultant filaments in an aqueous solution of the same solvent. Washing, stretching, drying and crimping complete the processing. Acrylic fibers are produced in a range of deniers, typically from 1 to 15. End uses include sweaters, hand-knitting yarns, rugs, awnings, boat covers, a precursor for carbon fiber, and beanies. Production of acrylic fibers is centered in the Far East, declining in Europe and now shut down (except for precursor) in the U.S.
Acrylic is lightweight, soft, and warm, with a wool-like feel. It dyes very well and has excellent colorfastness. It is resilient, retains its shape, and resists shrinkage and wrinkles. It is quite varied in form and sometimes has an appearance similar to wool or cotton.
Acrylic has recently been used in clothing as a cheaper alternative to cashmere, due to the similar feeling of the materials. The disadvantages of acrylic is that it tends to fuzz (or pill) easily and that it does not insulate the wearer as well as cashmere. Many products like fake pashmina or cashmina use this material to create the illusion of cashmere to the consumer.
Acrylic is resistant to moths, oils, and chemicals, and is very resistant to deterioration from sunlight exposure. However, static and pilling can be a problem.