Correlation between configuration/conformation of zirconocenes on the stereoselectivity of the propylene polymerization reaction |
| |
Authors: | Mario R Meneghetti Madalena C Forte Jairton Dupont |
| |
Affiliation: | (1) Grupo de Catálise, Instituto de Química, UFRGS, Av. Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil;(2) Centro de P&D, PPH Cia. de Polipropileno, Pólo Petroquímico de Triunfo, RS, Brazil |
| |
Abstract: | 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 ( 5-1-indenyl) zirconium (IV) dichloride, with C2 symmetry, produces isotatic polypropylene and isopropylidene( 5-cyclopentadienyl ( 5-9-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( 5-cyclopentadienyl) zirconium (IV) dichloride and bis( 5-indenyl zirconium (IV) dichloride at any temperature investigated (10–60°C). |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|