The Structure of Cationic Polyisoprene: Branching versus Cyclization. Issue 16 (21st June 2016)

• Record Type: Journal Article
• Authors: Rozentsvet, Victor A.; Kozlov, Valery G.; Korovina, Nelly A.; Stotskaya, Olesya A.; Gnezdilov, Oleg I.; Kostjuk, Sergei V.
• Is Part Of: Macromolecular chemistry and physics. Volume 217:Issue 16(2016:Aug.)
• Page Start: 1860
• Page End: 1867
• Publication Date: 2016-06-21
• Subjects: cationic polymerization -- fractionation -- microstructure -- polyisoprene; Polymers -- Periodicals; Polymerization -- Periodicals; Synthetic products -- Periodicals; Macromolecules -- Periodicals; 547.7
• DOI: 10.1002/macp.201600129
• Languages: English
• ISSNs: 1022-1352

Abstract

Abstract : The structure, molecular weight, and molecular weight distribution (MWD) of polyisoprene fractions, which were obtained during the fraction of polyisoprene with broad MWD ( M w / M n = 25.6) synthesized with t BuCl/TiCl4 initiating system have been investigated. It is established that chain transfer to polymer leading to branched macromolecules is responsible for the formation of polyisoprene with broad MWD and reduced unsaturation. It is shown for the first time that unsaturation decreased while the content of head and end groups in a single macromolecule increased with increasing molecular weight of polyisoprene fraction. The unsaturated part of the polymer chain consists of presumably trans ‐1, 4‐units independently of the molecular weight of polyisoprene fraction. Abstract : The reduced unsaturation of polyisoprene synthesized via cationic mechanism is consistent only with chain transfer to polymer leading to the formation of branched polymers with numerous head and end groups (up to 20–80).