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Molecular weight control and end group functionalization of polynorbornene by Ni(II)-initiated polymerization of norbornene in the presence of ethylene and ɑ-olefins

Molecular weight control and end group functionalization of polynorbornene by Ni(II)-initiated... AbstractHigh-molecular-weight vinyl-type polynorbornene (PN) was obtained in high yields by a highly active nickel-based phosphorane iminato complex in the presence of methylaluminoxane. Termination of norbornene polymerization by functionalized ɑ-olefins yielded soluble end group functionalized polynorbornenes of controlled molecular weight. The impact of the ɑ-olefins on yield and Mn depends significantly on the sterical situation at the olefins. No proof for the incorporation of the olefin at any other position than the chain end was observed. Considerations based on yields and Mn suggest that the Ni hydride species, which is most likely formed upon β-H elimination reaction in the scheme of olefin addition to the growing PN chain, initiates a new PN chain; in other words, chain transfer occurs through β-H elimination reaction. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png e-Polymers de Gruyter

Molecular weight control and end group functionalization of polynorbornene by Ni(II)-initiated polymerization of norbornene in the presence of ethylene and ɑ-olefins

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Publisher
de Gruyter
Copyright
© 2013 by Walter de Gruyter GmbH & Co.
ISSN
2197-4586
eISSN
1618-7229
DOI
10.1515/epoly.2001.1.1.150
Publisher site
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Abstract

AbstractHigh-molecular-weight vinyl-type polynorbornene (PN) was obtained in high yields by a highly active nickel-based phosphorane iminato complex in the presence of methylaluminoxane. Termination of norbornene polymerization by functionalized ɑ-olefins yielded soluble end group functionalized polynorbornenes of controlled molecular weight. The impact of the ɑ-olefins on yield and Mn depends significantly on the sterical situation at the olefins. No proof for the incorporation of the olefin at any other position than the chain end was observed. Considerations based on yields and Mn suggest that the Ni hydride species, which is most likely formed upon β-H elimination reaction in the scheme of olefin addition to the growing PN chain, initiates a new PN chain; in other words, chain transfer occurs through β-H elimination reaction.

Journal

e-Polymers – de Gruyter

Published: Dec 1, 2001

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