Crystalline structure and thermal property of polyethylene and isotactic polypropylene containing cyclopentane units in the main chain

Naofumi Naga, Michiyo Tsubooka, Shoji Suehiro, Yukio Imanishi

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Polyethylene and isotactic polypropylene having 1,2- or 1,3-disubstituted cyclopentane structures were prepared by copolymerization of ethylene or propylene with cyclopentene (CPE) or 1,5-hexadiene (HD) using zirconocene catalysts. Effect of the cyclopentane structures on the melting point and crystalline structure of the copolymers was investigated. In the case of ethylene-based copolymers, polyethylene containing 1,3-disubstituted cyclopentane structure, poly(ethylene-co-HD), showed a lower degree of melting-point depression and decreasing crystallinity with increasing cyclopentane contents than polyethylene containing 1,2-disubstituted cyclopentane structure, poly(ethylene-co-CPE). Expansion of crystalline unit cell, especially along the a-axis, with increasing cyclopentane content was observed in the wide-angle X-ray diffraction patterns of the poly(ethylene-co-HD). The phenomenon indicated incorporation of 1,3-disubstituted cyclopentane structure in the crystalline phase of polyethylene. On the other hand, both poly(propylene-co-CPE) and poly(propylene-co-HD) showed similar profiles in the relationship between the comonomer content and the melting point or the crystallinity of the copolymers.

Original languageEnglish
Pages (from-to)3041-3047
Number of pages7
Issue number8
Publication statusPublished - 2002 Apr 9


ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics
  • Inorganic Chemistry
  • Materials Chemistry

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