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Immobilization of Zirconocene into Silica Prepared by Non‐Hydrolytic Sol‐Gel Method
Author(s) -
Fisch Adriano,
Petry Cristiane F.,
Pozebon Dirce,
Stedile Fernanda C.,
Cardozo Nilo S. M.,
Secchi Argimiro R.,
dos Santos João H. Z.
Publication year - 2006
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.200651311
Subject(s) - methylaluminoxane , catalysis , polymerization , fourier transform infrared spectroscopy , materials science , molar mass distribution , ethylene , polymer chemistry , infrared spectroscopy , sol gel , polymer , silica gel , diffuse reflectance infrared fourier transform , metallocene , scanning electron microscope , nuclear chemistry , chemical engineering , chemistry , organic chemistry , composite material , photocatalysis , engineering , nanotechnology
Concomitant immobilization of zirconocene (Cp 2 ZrCl 2 ) into a silica matrix was performed during the SiO 2 synthesis through non‐hydrolytic sol‐gel method. Two different routes, varying the SiCl 4 :Si(OEt) 4 ratio were evaluated in terms of zirconocene content and catalyst activity in ethylene polymerization, using methylaluminoxane (MAO) as cocatalyst. The catalysts were characterized by Rutherford backscattering spectrometry, Fourier transform infrared spectroscopy, diffuse reflectance spectroscopy, scanning electron microscopy and X‐ray dispersive spectroscopy. The zirconocene content laid between 0.60 and 1.02 wt.% Zr/SiO 2 , depending upon the components ratio employed in the sol‐gel synthesis. Catalyst grains presented of irregular shape (20–100 µm size) and zirconocene distribution was not uniform. Both routes led to supported catalysts active in ethylene polymerization. Catalyst activity was intermediate between that exhibited by the homogeneous and the grafted zirconocene on silica. Resulting polyethylenes presented narrow molecular weight distribution and molecular weight slightly higher than that observed in the case of polymer produced with the homogeneous system.