Comprehensive structural characterization of polyisoprene synthesized via cationic mechanism. Issue 15 (12th May 2016)

• Record Type: Journal Article
• Authors: Rozentsvet, Victor A.; Korovina, Nelly A.; Stotskaya, Olesya A.; Kuznetsova, Marianna G.; Peruch, Frederic; Kostjuk, Sergei V.
• Is Part Of: Journal of polymer science. Volume 54:Issue 15(2016)
• Page Start: 2430
• Page End: 2442
• Publication Date: 2016-05-12
• Subjects: cationic polymerization -- polyisoprene -- microstructure; 547
• DOI: 10.1002/pola.28118
• Languages: English
• ISSNs: 0887-624X

Abstract

ABSTRACT: The microstructure of polyisoprene synthesized with t BuCl/TiCl4 initiating system is investigated using 1D and 2D (HSQC and HMBC) NMR spectroscopy. It is found that trans ‐1, 4‐units with regular (head‐to‐tail) and inverse (tail‐to‐tail) and (head‐to‐head) enchainments are predominant structures of unsaturated part of polymer chain, while 1, 2‐ and 3, 4‐units are presented in minor amounts. The new methodology for the quantitative calculation of the content of different structural units in polyisoprene chain including both types of inverse trans ‐1, 4‐addition (tail‐to‐tail and head‐to‐head) is proposed. It is shown that head groups consist of tert ‐butyl group connected to trans ‐1, 4‐unit of polyisoprene chain. In addition, two types of chlorine‐containing end groups are found ( trans ‐4, 1‐Cl and 4, 3‐Cl), while conjugated double bonds at the chain end are totally absent. The methodology for the calculation of number‐average functionality by tert ‐butyl head and chlorine end groups, respectively, is developed. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem.2016, 54, 2430–2442 Abstract : The assignment of all signals in NMR spectra to atoms of a cationic polyisoprene chain has been made. Particularly, two types of chlorine‐containing end groups are found ( trans ‐4, 1‐Cl and 4, 3‐Cl) and observed for the first time, while conjugated double bonds at the chain end are totally absent. In addition, the new methodology for quantitative calculation of the content of different structural units in the polyisoprene chain, including both types of inverse trans ‐1, 4‐addition (tail‐to‐tail and head‐to‐head) is proposed.