• Zanoni, Silvia
• Welle, Alexandre
• Cirriez, Virginie
• Nikolopoulos, Nikolaos
• Weckhuysen, Bm Bert

Abstract

<p>A commercial SiO₂ modified by the addition of a TiO₂ layer on its surface and pore walls offers a support for metallocene-based ethylene polymerization catalysts with a 35 % improved catalytic activity. The effect of such support modification on the catalyst particle fragmentation during polymerization reactions were assessed. This was performed by exposing the internal cross-section of several SiO₂ and Ti/SiO₂-based metallocene catalyst particles, polymerized at a wide range of reaction conditions, with a Focused-Ion Beam Scanning Electron Microscope (FIB-SEM), followed by a semi-quantitative analysis of polymer, catalyst and macropores of each 2D image obtained. The titanation of the SiO₂ lead to a support framework that fractures earlier and more efficiently. This was evidenced by the presence of several empty (polymer-free) cracks along the support dense-shell, found more extensively in the Ti-modified polymerized catalyst particle, which also resulted in a more sustained polymerized particles macroporosity during the course of the reaction.</p>

Topics

• pore
• surface
• polymer
• scanning electron microscopy
• crack
• titanium
• quantitative determination method