Acrylonitrile butadiene styrene
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From Wikipedia, the free encyclopedia
For other uses, see ABS (disambiguation).
Acrylonitrile butadiene styrene
Monomers in ABS polymer
A subset of common crosslinking motifs in ABS
ABS polymer grains
Identifiers
CAS Number 9003-56-9
ChemSpider None
ECHA InfoCard 100.127.708
PubChem CID 24756
CompTox DTXSID70858757
Dashboard (EPA
)
Properties
Chemical (C8H8·C4H6·C3H3N)n
formula
Density 1.060–1.080 g/cm3[1]
Solubility in Insoluble in water
water
Related compounds
Related Acrylonitrile, butadiene and styrene (monomer
compounds
s)
Except where otherwise noted, data are given for materials in
their standard state (at 25 °C [77 °F], 100 kPa).
verify (what is ?)
Infobox references
Acrylonitrile butadiene styrene
Physical properties
Density (ρ) 0.9–1.53 g/cm3; median,
1.07 g/cm3
Flammability 1.00
Thermal properties
Thermal conductivity (k) 0.1 W/(m·K)
Linear thermal expansion 12×10−5 K−1
coefficient (α)
Chemical resistance
Acids—concentrated Good
Acids—dilute Excellent
Alcohols Poor
Aldehydes Poor
Alkalis Excellent
Aromatic hydrocarbons Poor
Esters Poor
Halogenated hydrocarbons Poor
Ketones Poor
[2][3]
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]
ABS is amorphous and therefore has no true melting point.
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 crisscrossed 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.
Properties[edit]
ABS provides favorable mechanical properties such as impact resistance, toughness, and rigidity
when compared with other common polymers.[3] A variety of modifications can be made to improve
impact resistance, toughness, and heat resistance. The impact resistance can be amplified by
increasing the proportions of polybutadiene in relation to styrene and also acrylonitrile, although this
causes changes in other properties. Impact resistance does not fall off rapidly at lower temperatures.
Stability under load is excellent with limited loads. Thus, by changing the proportions of its
components, ABS can be prepared in different grades. Two major categories could be ABS for
extrusion and ABS for injection molding, then high and medium impact resistance. Generally ABS
would have useful characteristics within a temperature range from −20 to 80 °C (−4 to 176 °F).[5]
