Acta Chimica Sinica ›› 2001, Vol. 59 ›› Issue (10): 1783-1787. Previous Articles     Next Articles

Original Articles

球形MgCl2负载的MAO/rac-Et[Ind]2ZrCl2催化剂催化丙烯 聚合

关吉吉;郑莹;焦书科   

  1. 北京化工大学材料科学与工程学院;中国石油化工集团公司北京化工研究院
  • 发布日期:2001-10-15

Spherical MgCl2 supported MAO/rac-Et[Ind]2ZrCl2 catalyst for propylene polymerization

Guan Jiji;Zheng Ying;Jiao Shuke   

  • Published:2001-10-15

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

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