INVESTIGADORES
FERREIRA Maria Lujan
artículos
Título:
Characterization and Evaluation of Supported rac-Dimethylsilylenebis(indenyl)zirconium Dichloride on Ethylene Polymerization
Autor/es:
FERNANDO C. FRANCESCHINI; TATIANA T. R. DA TAVARES; DANIELA BIANCHINI; MARIA DO CARMO M. ALVES; MARÍA LUJÁN FERREIRA; JOAO H. Z. DOS SANTOS
Revista:
JOURNAL OF APPLIED POLYMER SCIENCE
Editorial:
JOHN WILEY & SONS INC
Referencias:
Lugar: Hoboken -USA; Año: 2009 vol. 112 p. 563 - 571
ISSN:
0021-8995
Resumen:
rac-Dimethylsilylenebis(indenyl)zirconium dichloride was grafted onto commercial methyl aluminoxane modified silica (SMAO) at different loadings (0.1–1.5 wt % Zr/SMAO). Supported catalysts were evaluated in ethylene polymerization with isoprenylaluminum as a cocatalyst. The characterization of two supported catalysts bearing 0.3 and 0.8 wt % Zr/SiO2 by extended X-ray absorption fine structure indicated that the number and the intensity of the peaks beyond the coordination shell, associated with the next nearest neighbors, depended on the Zr concentration. For the catalyst with a higher Zr content, only one peak (2.8 A ˚ ) was observed. The catalyst with 0.3 wt % Zr/SMAO presented two small peaks at 2.8 and 3.8 A ˚ . Polymers produced with the supported catalysts presented lower crystallinity and higher molar mass and polydispersity values in comparison to that produced by the homogeneous one. Gel permeation chromatogram deconvolution suggested the presence of four catalyst sites for the supported systems.