Synthesis of polyolefins with unique properties by using metallocene-type catalysts

Yukio Imanishi, Naofumi Naga, Michiyo Tsubooka

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

Copolymerization of ethylene and 1,5-hexadiene (HD) by zirconocene catalysts proceeded via cyclization-addition mechanism to form 1,3-didsubstituted cyclopentane structure in the polyethylene chain. The 1,3-cyclopentane structure was found to be taken in the crystalline structure of polyethylene (isomorphism) by partially chainging the trans zigzag chain into gauche conformation, thereby, inducing a transformation of orthorhombic crystal to pseudohexagonal crystal. Copolymerization of ethylene and cyclopentene (CPE) by zirconocene catalysts yielded copolymers having 1,2-disubstituted cyclopentane structure in the polyethylene chain. The 1,2-cyclopentane structure was not taken into the crystalline structure of polyethylene. The melting point (Tm) and the crystallinity (Xc) of polyethylene decreased by copolymerization of HD or CPE, and the Tm- and Xc-decreasing effect of CPE was stronger than HD. For copolymers of propylene and HD or CPE obtained with isospecific zirconocene catalyst, the isomorphism was not ovserved.

Original languageEnglish
Pages (from-to)45-62
Number of pages18
JournalMacromolecular Symposia
Volume195
DOIs
Publication statusPublished - 2003 Jun 1
Externally publishedYes

Keywords

  • 1,5-hexadiene
  • Copolymerization
  • Ethylene
  • Isomorphism
  • Zirconocene catalyst

ASJC Scopus subject areas

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

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