New Isotactic Polypropylenes via Metallocene Catalysts

Spaleck, Walter; Antberg, M.; Aulbach, Michael; Bachmann, Bernd; Dolle, Volker; Haftka, S.; Küber, Frank; Rohrmann, Jürgen; Winter, Andreas

doi:10.1007/978-3-642-79136-9_5

Cited by 92 publications

(124 citation statements)

References 14 publications

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“…Generally speaking, however, heterogeneous catalysts Since the discovery of marvelous metallocene catalysts by Kaminsky and Sinn in 1980, 1 much efin which metallocenes are directly fixed on the solid surface are less active than the correspondfort has been paid to modify the metallocene ligands [2][3][4][5][6][7] as well as to develop active heterogeing homogeneous catalysts. In addition, the complexity arising from the heterogeneity of the surneous metallocene catalysts.…”

Section: Introductionmentioning

confidence: 99%

Syntheses of poly(siloxane)-supported zirconocene catalysts and application to olefin polymerizations

Arai

Uozumi

Soga

1998

J. Polym. Sci. A Polym. Chem.

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Section: Introductionmentioning

confidence: 99%

Syntheses of poly(siloxane)-supported zirconocene catalysts and application to olefin polymerizations

Arai

Uozumi

Soga

1998

J. Polym. Sci. A Polym. Chem.

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“…However, the dimethylsilylene bridged analogue was found to produce isotactic rich poly(propylene), presumably due to the stationary insertion of propylene 15) . These results suggest that the bulkiness of the isopropyl group was not enough to change the propagation mechanism from migratory insertion to stationary insertion for the production of isotactic poly(-propylene), and the slight change of the bridge structure was responsible for these different microstructures.…”

Section: Resultsmentioning

confidence: 97%

“…Based on these results, this catalyst may produce iso-syndio stereo block poly(propylene). Actually, it was reported that Me 2 Si(3-MeCp)(Flu)ZrCl 2 /MAO produced poly(propylene) which had the coexistence of measurable amounts of isotactic and syndiotactic sequences 15) , but further investigations are needed to confirm the formation of this stereo block poly(propylene).…”

mentioning

confidence: 97%

Propylene polymerization with Ph2C(3-RCp)(Flu)ZrCl2 [R = Me, i-Pr, PhCH2, Me3Si] catalysts activated with MAO and Me2PhNH·B(C6F5)4/i-Bu3Al

Yano

Kaneko

Sato

et al. 1999

Macromol. Chem. Phys.

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SUMMARY: Propylene polymerization was conducted with Ph 2 C(R-Cp)(Flu)ZrCl 2 [R = Me, i-Pr, PhCH 2 , Me 3 Si] catalysts in combination with methylaluminoxane (MAO) and dimethylanilinium tetrakis(pentafluorophenyl)borate (Me 2 PhNH N B(C 6 F 5 ) 4 ) as cocatalyst; the dependence of the stereoregularity of poly(propylene) on cocatalysts and bulkiness of the substituents in b -position of the cyclopentadienyl ligand was studied. Methyl and i-propyl substituted metallocene catalysts produce hemi-isotactic poly(propylene). These results are in good agreement with the results of the isopropylidene bridged metallocene analogue. The benzyl substituted metallocene catalyst produces syndiotactic poly(propylene) regardless of the cocatalyst. This means that this substituent group does not affect migration insertion of propylene. Stereoregularity of poly(propylene) obtained with diphenylmethylidene(3-trimethylsilylcyclopentadienyl)(fluorenyl)zirconium dichloride (Ph 2 C(Me 3 SiCp)(Flu)ZrCl 2 ) as a catalyst was significantly influenced by the cocatalyst. Me 2 PhNH N B(C 6 F 5 ) 4 /triisobutylaluminium(i-Bu 3 Al) produces poly(propylene) with 65% racemic and 23% meso pentads at 40 8 C, whereas the MAO activated catalyst produces isotactic rich poly(propylene). Fractionation experiments indicated that Me 2 PhNH N B(C 6 F 5 ) 4 /i-Bu 3 Al forms two active sites, one of them being the same as that of the MAO activated catalyst, the other one producing syndiotactic rich poly(propylene).

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“…1). The tacticity of polypropene prepared with the bridged catalysts 1 and 2 has been reported 19) . In polypropene produced with the silicon-bridged catalyst 2 the mmmm pentad has a relative abundance of 82%, whereas the mmmm pentad in polypropene produced with the ethylene-bridged metallocene 1 has an abundance of 80%.…”

Section: Resultsmentioning

confidence: 99%