Styrene-acrylonitrile (SAN) copolymers are transparent plastics with excellent chemical resistance and high heat resistance. They are usually hard and rigid and as a result have good dimensional stability and load-bearing capability. For all the benefits you can reap with SAN resins, they are most often chosen for clear applications because of their transparency.

As with other polymers, properties like tensile strength and resistance to impact are adjusted by changes in molecular weight. Changes in the styrene/acrylonitrile ratio can also contribute to these variations. Tensile strength can range from 10,000 and 12,000 psi and notched Izod impact values range from 0.2 to 0.5 ft.-lb./in.

SAN is not the only styrenic plastic commonly used. ABS or acrylonitrile-butadiene-styrene is used in even larger volumes than SAN. SAN is basically ABS without the rubber. Because it has no rubber, the impact resistance suffers, but heat and chemical resistance, tensile strength and flexural strength are superior.