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Polymerization of ethene initiated with a mixture of siloxane-bridged mono- and dinuclear zirconocenes

✍ Scribed by Dong-ho Lee; Keun-byoung Yoon; Seok-kyun Noh; Su-chan Kim; Wan-soo Huh

Publisher
John Wiley and Sons
Year
1996
Tongue
English
Weight
285 KB
Volume
17
Category
Article
ISSN
1022-1336

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✦ Synopsis

Abstract

In the polymerization of ethene cocatalyzed with modified methylaluminoxane, the catalyst activities of the siloxane‐bridged dinuclear zirconocenes, tetramethyldisiloxanediylbis(cyclopentadienylindenylzirconium dichloride) (3) and hexamethyltrisiloxanediylbis(cyclopentadienylindenylzirconium dichloride) (4) were lower than that obtained with the siloxane‐bridged mononuclear zirconocene, tetramethyldisiloxanediyldicyclopentadienyldimethylzirconium (1). On the other hand, weight‐average molecular weight M̄~w~ and ratio of weight‐ to number‐average molecular weights M̄~w~/M̄~n~ of polyethene (PE) obtained with 3 or 4 were higher than those of PE obtained with 1. For a binary mixture of 1/3 or 1/4, it was found that the obtained PE exhibits a bimodal molecular weight distribution for an appropriate composition of the mixed zirconocenes. M̄~w~/M̄~n~ of PE could be adjusted by changing the relative concentrations of the two zirconocenes.

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