Its glass transition temperature is approximately 105 °C (221 °F). ABS is amorphousand therefore has no true melting point.
ABS is a terpolymer made by polymerizing styrene and acrylonitrile in the presence of polybutadiene.
Theproportions can vary from 15 to 35% acrylonitrile, 5 to 30% butadiene and 40 to 60% styrene.
The result is along chain of polybutadiene criss-crossed with shorter chains of poly(styrene-co-acrylonitrile). The nitrilegroups from neighboring chains, being polar, attract each other and bind the chains together, making ABSstronger than pure polystyrene. The styrene gives the plastic a shiny, impervious surface.
For the majority ofapplications, ABS can be used between −20 and 80 °C (−4 and 176 °F) as its mechanical properties varywith temperature. The properties are created by rubber toughening,
where fine particles of elastomer aredistributed throughout the rigid matrix.