Study of the Fragmentation Process of Different Supports for Metallocenes by Laser Scanning Confocal Fluorescence Microscopy (LSCFM)
✍ Scribed by Yong-Jun Jang; Corinna Naundorf; Markus Klapper; Klaus Müllen
- Publisher
- John Wiley and Sons
- Year
- 2005
- Tongue
- English
- Weight
- 675 KB
- Volume
- 206
- Category
- Article
- ISSN
- 1022-1352
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✦ Synopsis
Abstract
**Summary:**The fragmentation of supports, a key issue for the polymerization of olefins via supported metallocene catalysts, was investigated by laser scanning confocal fluorescence microscopy (LSCFM). Metallocenes were immobilized on silica and on two organic supports, namely polystyrene latex particles and a polystyrene resin, which were stained by fluorescent perylene dyes. All supported catalysts showed different activities in the ethylene polymerization under the same reaction conditions. Recording fluorescence images of the polyolefin product beads at different polymerization times by LCSFM proved different fragmentation processes for the catalyst. While for the µm‐sized polystyrene resins almost no fragmentation was observed, supports based on aggregated latex particles fragmented throughout the bead from the beginning, corresponding to the multi‐grain model established for Ziegler‐catalysts. For the silica particles a fragmentation starting from the outer spheres to the core was detected, confirming in a fast and easy way the layer‐by‐layer model developed by electron microscopy studies.
SEM images of the catalyst supported on (A) microsized PS beads, (B) nanosized PS beads and (C) silica gel.
magnified imageSEM images of the catalyst supported on (A) microsized PS beads, (B) nanosized PS beads and (C) silica gel.