Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
PO: Polymerphysik
PO 6: Poster: Dünne Filme und Grenzfl
ächen
PO 6.5: Poster
Dienstag, 2. März 1999, 14:00–16:00, Foyer
A new research approach: polymerization on flat surfaces — •J. Loos1, P. C. Thuene2, P. J. Lemstra1, and J. W. Niemantsverdriet2 — 1Dutch Polymer Institute, Eindhoven Polymer Labs., NL — 2Schuit Institute of Catalysis, Eindhoven University of Technology, NL
A surface science model for the Phillips ethylene polymerization catalyst has been prepared, by impregnating aqueous CrO3 on a flat silicon (100) substrate covered by amorphous silica [1]. Impregnating in a spin-coating technique offers control over the chromium loading, which was varied between 0.4 and 4.0 Cr/nm2. Upon calcination chromium is anchored to the support over Cr-O-Si ester bonds. The model catalyst polymerize ethylene at a wide temperature range from RT to 160(C and atmospheric pressure after being activated in 80/20 He/O2 at 650(C, confirming its validity as a model for the industrial catalyst. X-ray photoelectron spectroscopy (XPS) investigations of the activated Si surface before and after polymerization show the development of a polymer layer. The surface morphology of the as-polymerizes (nascent) polyethylene is studied using microscopy techniques (optical and atomic force microscope). Time-resolved studies at different polymerization temperatures of the polymer layer formation on the Si substrate lead to a better understanding of the polymerization process.
[1] P. C. Thuene, C. P. J. Verhagen, M. J. G. van den Boer, J. W. Niemantsverdriet J Phys Chem B 101 (1997) 8559