Polyisoprene

Polyisoprene is a collective name for polymers that are produced by polymerization of isoprene. In principle, four different isomers can form. Cis-1,4-polyisoprene, which is also called isoprene rubber, is a major ingredient of natural rubber. Trans-1,4-polyisoprene is a major ingredient of gutta-percha. Annual worldwide production of polyisoprene was 13,000 kilotonne in 2007.[1]

Pieces of polyisoprene in Hutchinson's Research and Innovation center in France.

Property
Four isomers of Polyisoprene

The percentage of repeating units of polyisoprene comprising each type of polymer bond is dependent on the reaction mechanism.

Anionic chain polymerization, which is initiated by n-Butyllithium, produces cis-1,4-polyisoprene dominant polyisoprene. 90–92% of repeating units are cis-1,4-, 2–3% trans-1,4- and 6–7% 3,4-units.[2]

Coordinative chain polymerization: With Ziegler–Natta catalyst TiCl4/Al(i-C4H9)3, more pure Cis-1,4-polyisoprene is formed. Natural rubber is more pure cis-1,4-polyisoprene. With Ziegler–Natta catalyst VCl3/Al(i-C4H9)3, trans-dominant polyisoprene is formed.[3]


1,2 and 3,4 dominant polyisoprene is produced MoO2Cl2 catalyst supported by phosphorus ligand and Al(OPhCH3)(i-Bu)2 co-catalyst.[4]

Usage

Natural Gutta-percha and synthesized trans-1,4-polyisoprenes are used for golf balls. Natural rubber and synthesized cis-1,4-polyisoprene are used for elastomer.

Polyisoprene condoms provide an alternative to traditional latex condoms.

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See also

References
  1. Sebastian Koltzenburg, Michael Maskos, Oskar Nuyken, Polymere: Synthese, Eigenschaften und Anwendungen, Springer, Berlin, 2012, S. 424.
  2. Jürgen Falbe, Manfred Regitz (Hrsg.): CD Römpp Chemie Lexikon, Thieme, Stuttgart, 1995.
  3. Bernd Tieke, Makromolekulare Chemie, 3. Auflage, Wiley-VCH, Weinheim, 2014, S. 149.
  4. 1,2- and 3,4-rich polyisoprene synthesized by Mo(VI)-based catalyst with phosphorus ligand Polymer Science Series B September 2016, Volume 58, Issue 5, pp 495–502
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