Study of molecular size in ethylene-propene copolymerization with zirconocene and hafnocene catalysts

Naofumi Naga; Yoshiaki Ohbayashi; Kooji Mizunuma

doi:10.1002/marc.1997.030180912

Study of molecular size in ethylene-propene copolymerization with zirconocene and hafnocene catalysts

Naofumi Naga, Yoshiaki Ohbayashi, Kooji Mizunuma

Research output: Contribution to journal › Article › peer-review

23 Citations (Scopus)

Abstract

Ethylene-propene copolymerization was carried out with Cp₂MCl₂ (Cp = cyclopentadienyl), rac-Et(Ind)₂MCl₂, rac-Me₂Si(Ind)₂MCl₂ (Et = ethylene, Me₂Si = dimethylsilyl, Ind = indenyl, M = Zr or Hf)/methylaluminoxane. In the case of using ansa-hafnocenes, the minimum molecular size (extended chain length) of ethylene-propene copolymer was obtained at about 50 mol-% of propene content in the copolymer. The polymerization activity decreased with increase of propene feed ratio in non-bridged non-specific metallocenes. Higher polymerization activities were observed for the copolymerization compared to ethylene and propene homo-polymerization with ansa-isospecific metallocenes. The factor of molecular size lowering was studied by the chain propagation and chain transfer reaction.

Original language	English
Pages (from-to)	837-851
Number of pages	15
Journal	Macromolecular Rapid Communications
Volume	18
Issue number	9
DOIs	https://doi.org/10.1002/marc.1997.030180912
Publication status	Published - 1997 Sep
Externally published	Yes

ASJC Scopus subject areas

Organic Chemistry
Polymers and Plastics
Materials Chemistry

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title = "Study of molecular size in ethylene-propene copolymerization with zirconocene and hafnocene catalysts",

abstract = "Ethylene-propene copolymerization was carried out with Cp2MCl2 (Cp = cyclopentadienyl), rac-Et(Ind)2MCl2, rac-Me2Si(Ind)2MCl2 (Et = ethylene, Me2Si = dimethylsilyl, Ind = indenyl, M = Zr or Hf)/methylaluminoxane. In the case of using ansa-hafnocenes, the minimum molecular size (extended chain length) of ethylene-propene copolymer was obtained at about 50 mol-% of propene content in the copolymer. The polymerization activity decreased with increase of propene feed ratio in non-bridged non-specific metallocenes. Higher polymerization activities were observed for the copolymerization compared to ethylene and propene homo-polymerization with ansa-isospecific metallocenes. The factor of molecular size lowering was studied by the chain propagation and chain transfer reaction.",

author = "Naofumi Naga and Yoshiaki Ohbayashi and Kooji Mizunuma",

year = "1997",

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doi = "10.1002/marc.1997.030180912",

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T1 - Study of molecular size in ethylene-propene copolymerization with zirconocene and hafnocene catalysts

AU - Naga, Naofumi

AU - Ohbayashi, Yoshiaki

AU - Mizunuma, Kooji

PY - 1997/9

Y1 - 1997/9

N2 - Ethylene-propene copolymerization was carried out with Cp2MCl2 (Cp = cyclopentadienyl), rac-Et(Ind)2MCl2, rac-Me2Si(Ind)2MCl2 (Et = ethylene, Me2Si = dimethylsilyl, Ind = indenyl, M = Zr or Hf)/methylaluminoxane. In the case of using ansa-hafnocenes, the minimum molecular size (extended chain length) of ethylene-propene copolymer was obtained at about 50 mol-% of propene content in the copolymer. The polymerization activity decreased with increase of propene feed ratio in non-bridged non-specific metallocenes. Higher polymerization activities were observed for the copolymerization compared to ethylene and propene homo-polymerization with ansa-isospecific metallocenes. The factor of molecular size lowering was studied by the chain propagation and chain transfer reaction.

AB - Ethylene-propene copolymerization was carried out with Cp2MCl2 (Cp = cyclopentadienyl), rac-Et(Ind)2MCl2, rac-Me2Si(Ind)2MCl2 (Et = ethylene, Me2Si = dimethylsilyl, Ind = indenyl, M = Zr or Hf)/methylaluminoxane. In the case of using ansa-hafnocenes, the minimum molecular size (extended chain length) of ethylene-propene copolymer was obtained at about 50 mol-% of propene content in the copolymer. The polymerization activity decreased with increase of propene feed ratio in non-bridged non-specific metallocenes. Higher polymerization activities were observed for the copolymerization compared to ethylene and propene homo-polymerization with ansa-isospecific metallocenes. The factor of molecular size lowering was studied by the chain propagation and chain transfer reaction.

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