关键词: 氯化镁, 氯化锆, 金属茂络合物, 催化, 丙烯, 聚合

Propylene polymerization was carried out with heterogeneous catalyst prepared by supporting methyl-aluminoxane (MAO) on spherical MgCl2 only and mixing it with rac-Et[Ind]2ZrCl2 before polymerization, which eliminated the need for a supporting step of rac-Et[Ind]2ZrCl2. Under the activation of AlEt3 and lower Al(MAO)/Zr mole ratio, e.g. 150, in the absence of soluble MAO, the fair good activity of catalyst, e.g. 10^7 gPP/mol-Zr·h, could be obtained, which is ten times higher than homogeneous catalyst. The influence of polymerization temperature, pressure of propylene, Al(MAO)/Zr mole ratio and catalyst concentration on polymerization activity and molecular weight of produced polypropylene was strdued. The sequence structure of i-PP produced by homogeneous and heterogeneous catalyst was determined by 13^C NMR spectra. It was found that the isotacticity of i-PP obtained by heterogeneous systems was higher, its pentad sequence [mmmm] increased to 79.5% from 52.6% for homogeneous systems. The particles morphology of catalyst and polymer was observed by scanning electron microscopy (SEM). It was found that the polymer particles showed spherical from, which copy the spherical morphology of catalyst.

Key words: MAGNESIUM CHLORIDE, ZIRCONIUM CHLORIDE, METALLOCENES, CATALYSIS, PROPENE, POLYMERIZATION