ABS PLASTICS.

The letters ABS identify the family of acrylonitrile-butadiene-styrene. Common trade names for these materials are Cycolac, Magnum, and Lustran. They generally are opaque and distinguished by a good balance of properties, including high impact strength, rigidity, and hardness over a temperature range of -40 to 230 F (-40 to 110 C). Compared to other structural or engineering plastics, they are generally considered to fall at the lower end of the scale. Medium impact grades are hard, rigid, and tough and are used for appearance parts that require high strength, good fatigue resistance, and surface hardness and gloss. High impact grades are formulated for similar products where additional impact strength is gained at some sacrifice in rigidity and hardness. Low-temperature impact grades have high impact strength down to -40 F (-40 C). Again, some sacrifice is made in strength, rigidity, and heat resistance. Heat-resistant, high-strength grades provide the best heat resistance-continuous use up to about 200 F (93 C), and a 264 lb/in ² (1.8 MPa) heat deflection temperature of around 215 F (102 C). Impact strength is about comparable to that of medium impact grades, but strength, modulus of elasticity, and hardness are higher. At stresses above their tensile strength, ABS plastics usually yield plastically instead of rupturing, and impact failures are ductile. Because of relatively low creep, they have good long-term load-carrying ability. This low creep plus low water absorption and relatively high heat resistance provide ABS plastics with good dimensional stability. Transparent grades are available. ABS plastics...