Acrylonitrile butadiene styrene (ABS)

ABS is a terpolymer made by polymerizing styrene and acrylonitrile in the presence of polybutadiene. The proportions can vary from 15% to 35% acrylonitrile, 5% to 30% butadiene and 40% to 60% styrene. The result is a long chain of polybutadiene criss-crossed with shorter chains of poly(styrene-co-acrylonitrile). The nitrile groups from neighboring chains, being polar, attract each other and bind the chains together, making ABS stronger than pure polystyrene. The acrylonitrile also contributes chemical resistance, fatigue resistance, hardness, and rigidity, while increasing the heat deflection temperature. The styrene gives the plastic a shiny, impervious surface, as well as hardness, rigidity, and improved processing ease. The polybutadiene, a rubbery substance, provides toughness and ductility at low temperatures, at the cost of heat resistance and rigidity. For the majority of applications, ABS can be used between ?20 and 80 �C (?4 and 176 �F), as its mechanical properties vary with temperature. The properties are created by rubber toughening, where fine particles of elastomer are distributed throughout the rigid matrix.

Applications

ABS's light weight and ability to be injection molded and extruded make it useful in manufacturing products such as drain-waste-vent (DWV) pipe systems. Musical instruments such as recorders, plastic oboes and clarinets, piano movements, and keyboard keycaps are commonly made out of ABS. Other uses include golf club heads (because of its good shock absorbance), automotive trim components, automotive bumper bars, binoculars, inhalers, monoculars, nebulizers, non-absorbable sutures, tendon prostheses, drug-delivery systems tracheal tubes,[13] enclosures for electrical and electronic assemblies (such as computer cases), protective headgear, whitewater canoes, buffer edging for furniture and joinery panels, luggage and protective carrying cases, pen housing, and small kitchen appliances. Toys, including LEGO and Kre-O bricks, are a common application Household and consumer goods comprise the major applications of ABS.