ISSN:
1436-2449
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Summary The catalytic performance (activity and polymer properties) of metallocenes with different symmetries in combination with methylaluminoxane (MAO) in the polymerization of propylene has been investigated at different temperatures, under standardized reaction conditions. The zirconocene rac-ethylene (η5-1-indenyl) zirconium (IV) dichloride, with C2 symmetry, produces isotatic polypropylene and isopropylidene(η5-cyclopentadienyl (η5-9-fluorenyl) zirconium (IV) dichloride, with C S symmetry, syndiotactic polypropylene. The degree of the tacticity of these polymers increases with decreasing polymerization temperature. Only atactic polypropylene was formed with the unbridged zirconocenes bis(η5-cyclopentadienyl) zirconium (IV) dichloride and bis(η5-indenyl zirconium (IV) dichloride at any temperature investigated (10–60°C).
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00297608
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