Back to Search Start Over

Optimization of a silica supported bis(butylcyclopentadienyl)-zirconium dichloride catalyst for ethylene polymerization

Authors :
Santos, João Henrique Zimnoch dos
Larentis, Ariane
Rosa, Marcelo Barbosa da
Krug, Cristiano
Baumvol, Israel Jacob Rabin
Dupont, Jaïrton
Stedile, Fernanda Chiarello
Forte, Madalena de Camargo
Source :
Macromolecular Chemistry and Physics; April 1999, Vol. 200 Issue: 4 p751-757, 7p
Publication Year :
1999

Abstract

A series of heterogeneous α-olefin polymerization catalysts were prepared by the immobilization of bis(butylcyclopentadienyl)zirconium dichloride, (nBuCp)<INF>2</INF>ZrCl<INF>2</INF>, on a commercial silica support (Grace 948) using different procedures. The preparation parameters, namely, silica activation temperature, grafting temperature, grafting time, and solvent, were evaluated in terms of metal content on silica and ethylene homopolymerization activity. Metal contents were determined by Rutherford back-scattering spectrometry (RBS). In the temperature activation range between 373 and 723 K, silica surface saturation in Zr was found to be around 0.34 wt.-% Zr/SiO<INF>2</INF>. However, polymer polydispersity is shown to decrease with increasing support activation temperature. A better control in the generation of the active surface species was achieved with thermal pretreatment temperatures close to 723 K. The grafting reaction was seen to be immediate. Longer grafting times or higher temperatures bore deactivated species. Practically all the systems were active in ethylene polymerization in the presence of MAO, but the highest yield was obtained after grafting at 353 K for 1 h in toluene solution, employing silica pretreated at 723 K.

Details

Language :
English
ISSN :
10221352 and 15213935
Volume :
200
Issue :
4
Database :
Supplemental Index
Journal :
Macromolecular Chemistry and Physics
Publication Type :
Periodical
Accession number :
ejs2348056
Full Text :
https://doi.org/10.1002/(SICI)1521-3935(19990401)200:4<751::AID-MACP751>3.0.CO;2-2