Polyisobutene (polyisobutylene) is a class of organic polymers prepared by polymerization of
isobutene
Isobutylene (or 2-methylpropene) is a hydrocarbon with the chemical formula . It is a four-carbon branched alkene (olefin), one of the four isomers of butylene. It is a colorless flammable gas, and is of considerable industrial value.
Producti ...
. The polymers often have the formula Me
3C
H2CMe2sub>nX (Me = CH
3, X = H, F). They are typically colorless gummy solids.
Polymerization is typically initiated with a strong Brønsted or
Lewis acid. The
molecular weight
A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bioch ...
(MW) of the resulting polymer determines the applications. Low MW polyisobutene, a mixture of
oligomers with
Mns of about 500, is used as
plasticizer
A plasticizer ( UK: plasticiser) is a substance that is added to a material to make it softer and more flexible, to increase its plasticity, to decrease its viscosity, and/or to decrease friction during its handling in manufacture.
Plasticiz ...
s. Medium and high MW polyisobutenes, with M
n ≥ 20,000, are components of commercial
adhesives.
[{{cite encyclopedia , author1=Kenneth S. Whiteley , author2=T. Geoffrey Heggs , author3=Hartmut Koch , author4=Ralph L. Mawer , author5=Wolfgang Immel , title=Polyolefins , encyclopedia=Ullmann's Encyclopedia of Industrial Chemistry , year=2005 , publisher=Wiley-VCH , place=Weinheim , doi=10.1002/14356007.a21_487]
See also
*
Butyl rubber
Butyl rubber, sometimes just called "butyl", is a synthetic rubber, a copolymer of isobutylene with isoprene. The abbreviation IIR stands for isobutylene isoprene rubber. Polyisobutylene, also known as "PIB" or polyisobutene, (C4H8)n, is the ho ...
*
Polybutene Polybutene is an organic polymer made from a mixture of 1-butene, 2-butene, and isobutylene. Ethylene steam cracker C4s are also used as supplemental feed for polybutene. It is similar to polyisobutylene (PIB), which is produced from essentially ...
References
Organic polymers