Copolymerization of ethylene and 1,7-octadiene, 1,9-decadiene with zirconocene catalysts

Naofumi Naga, Yukio Imanishi

Research output: Contribution to journalArticle

39 Citations (Scopus)

Abstract

Copolymerizations of ethylene and 1,7-octadiene (OD) and 1,9-decadiene (DD) were investigated with various non-bridged and bridged zirconocene catalysts using methylisobutylaluminoxane as a cocatalyst. The resulting copolymers were extracted with boiling o-dichlorobenzene (ODCB), and the structure of the boiling ODCB-soluble part was studied by 1H, 13C NMR and DEPT (distortionless enhancement of polarization transfer) spectroscopy. In the case of ethylene/OD copolymerization, the ligand structure of the zirconocene catalysts strongly affected the propagation mode of OD. The zirconocene catalysts having cyclopentadienyl or pentamethylcyclopentadienyl ligands gave copolymers having 1-hexenyl and 1,3-disubstituted cycloheptane units, derived from 1,2-addition propagation and addition - cyclization propagation of OD, respectively. On the other hand, the zirconocene catalysts with indenyl ligand produced the copolymers having exclusively 1,3-disubstituted cycloheptane units. Furthermore, the copolymer prepared by diphenylmethylene(cyclopentadienyl)(9-fluorenyl)zirconium dichloride was crosslinked. The diastereostructure of the 1,3-disubstituted cycloheptane units in the copolymers was not influenced by the stereospecificity of the catalysts used, and a cis-structure was preferentially formed. In the case of the copolymerization of ethylene and DD, the C2v- symmetric zirconocene catalysts produced the copolymers with 1-octenyl branches derived from 1,2-addition propagation of DD. Other C2- and Cs-symmetric zirconocene catalysts with bulky ligands yielded copolymers with crosslinking structures derived form addition propagation of sidechain unsaturated bond of 1,2-added DD units.

Original languageEnglish
Pages (from-to)2155-2162
Number of pages8
JournalMacromolecular Chemistry and Physics
Volume203
Issue number15
DOIs
Publication statusPublished - 2002 Oct 31
Externally publishedYes

Keywords

  • Copolymerization
  • Stereospecificity
  • Zirconocene catalysts

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Polymers and Plastics
  • Materials Chemistry

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