styrene-acrylonitrile copolymer

chemical compound
verifiedCite
While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions.
Select Citation Style
Feedback
Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login).
Thank you for your feedback

Our editors will review what you’ve submitted and determine whether to revise the article.

Also known as: SAN

styrene-acrylonitrile copolymer (SAN), a rigid, transparent plastic produced by the copolymerization of styrene and acrylonitrile. SAN combines the clarity and rigidity of polystyrene with the hardness, strength, and heat and solvent resistance of polyacrylonitrile. It was introduced in the 1950s and is employed in automotive parts, battery cases, kitchenware, appliances, furniture, and medical supplies.

SAN consists of styrene units and acrylonitrile units in a ratio of approximately 70 to 30. The two compounds are mixed in bulk-liquid form or in a water-based emulsion or suspension, and polymerization is conducted under the action of free-radical initiators. The resultant plastic material displays better resistance to heat and solvents than does polystyrene alone. The impact resistance of the copolymer is not satisfactory for many engineering applications, however, and styrene and acrylonitrile are therefore often copolymerized with admixtures of butadiene rubber to produce a more shatter-proof product known as ABS, or acrylonitrile-butadiene-styrene copolymer.

This article was most recently revised and updated by William L. Hosch.