Polyisobutene
Polyisobutene (polyisobutylene) is a class of organic polymers prepared by polymerization of isobutene. The polymers often have the formula MeC[CHCMe]X (Me = CH, X = H, F). They are typically colorless gummy solids. Polymerization is typically initiated with a strong Bronsted or Lewis acid. The molecular weight (MW) of the resulting polymer determines the applications. Low MW polyisobutene, a mixture of oligomers with Ms of about 500, is used as plasticizers. Medium and high MW polyisobutenes, with M ≥ 20,000, are components of commercial adhesives.