ABSTRACT
ABSTRACT: Four kinds of supported catalysts A, B, C and D were prepared and compared. The catalyst composition and microstructure was studied via surface properties measurement, IR and XPS. The polymerizing ability was evaluated and the corresponding polymers were characterized using isotacticity measurement, 13C-NMR and DSC. As a result, the polymerization activities are in the order of A > B > D > C, which are in accordance with the order of surface area value of the four kind of catalysts. XPS data showed that the Ti2P3/2 peaks of catalyst move to a lower energy range, and the value is in the order of Cat A > B > D = C. This indicates that the TiCl4 ⋅ MgCl2 ⋅ DBP (di-butyl phthalate) binding energy of different catalyst are in the same order with that of XPS. Which lead to the isotactic index and the [mm] value of polymers of four catalysts are in the order of Cat A > B > D > C and the Tm of four catalysts are in the order of Cat A > B > C > D. Therefore, we show that the combination ability of complexe TiCl4 ⋅ MgCl2 ⋅ DBP could influence the polymer isotacticity and the polypropylene melting point increases with the isotacticity.
