Acrylonitrile butadiene styrene

Acrylonitrile butadiene styrene (ABS) (chemical formula (C8H8)x·(C4H6)y·(C3H3N)z) is a common thermoplastic polymer. Its glass transition temperature is approximately 105 °C (221 °F).[4][failed verification] ABS is amorphous and therefore has no true melting point.

Acrylonitrile butadiene styrene

Monomers in ABS polymer

ABS polymer grains
Identifiers
  • 9003-56-9 Y
ChemSpider
  • None
ECHA InfoCard 100.127.708
Properties
(C8H8·C4H6·C3H3N)n
Density 1.060–1.080 g/cm3[1]
Insoluble in water
Related compounds
Related compounds
Acrylonitrile, butadiene and styrene (monomers)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references
Acrylonitrile butadiene styrene
Physical properties
Density (ρ)0.9–1.53 g/cm3; median, 1.07 g/cm3
Flammability1.00
Thermal properties
Thermal conductivity (k)0.1 W/(m·K)
Linear thermal expansion coefficient (α)12×10−5 K−1
Chemical resistance
AcidsconcentratedGood
AcidsdiluteExcellent
AlcoholsPoor
AldehydesPoor
AlkalisExcellent
Aromatic hydrocarbonsPoor
EstersPoor
Halogenated hydrocarbonsPoor
KetonesPoor
[2][3]

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.[3] 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.[5] The properties are created by rubber toughening, where fine particles of elastomer are distributed throughout the rigid matrix.