ISSN:
0025-116X
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Ethylene polymerization, catalyzed by Cp2TiEtCl or Cp2TiMeCl and cocatalyzed by oxyaluminium compounds, formed via hydrolysis of AlEtCl2, AtEt2Cl, AlEt3, AlMeCl2, AlMe2Cl, AlMe3, and AlEt(OBu)Cl, was studied. The cocatalytic activity of oxyaluminium compounds was found to decrease with increasing number of alkyl substituents in the corresponding alanes. The only inactive cocatalyst from the oxyaluminium compounds studied is the one formed via hydrolysis of AlEt(OBu)Cl. Oxyaluminium compounds from methylalanes are substantially less active than those from ethylalanes. If the same aloxane cocatalyst is employed, the catalytic activities of both Cp2TiEtCl and Cp2TiMeCl are similar. The molecular weight distributions of polyethylene are narrow for the systems Cp2TiRCl/(oxyaluminium compounds from AlEtCl2); fairly broader distributions were found for systems Cp2TiRCl/(oxyaluminium compounds from AlMeCl2). Systems with oxyaluminium compounds from dialkyl- or trialkylalanes yield polyethylene with distinctly bimodal distribution curves. The mechanism of ethylene polymerization catalyzed by titanocene systems cocatalyzed by oxyaluminium compounds is discussed.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/macp.1981.021820413
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