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由X光粉末图和聚合数据得到:研磨法制聚乙烯高效催化剂TiCl_4-MgCl_2,研磨的作用是使层型结构的载体MgCl_2沿结合力较弱的层间碎裂变为～100的微晶,提供足够的比表面,使TiCl_4达单分子层分散,TiCl_4被烷基铝还原产生Ti~(3+)在载体表面呈单原子分散,基本上都可起活性中心作用,这就是高效的根源,MgCl_2和TiCl_3具有类似的层型结构且Mg~(2+)和Ti~(3+)半径相近,是MgCl_2作为良好载体的结构基础,活性组分作单分子层分散,基本上都可起活性中心作用,这一“高效机理”可推广用于其它聚烯烃高效催化剂,文中还讨论了活性中心聚合速度和其它有关高效催化剂结构机理问题。
From the X-ray powder images and the polymerization data, we get: The polycrystalline polyethylene catalyst TiCl_4-MgCl_2 is ground by grinding method, the effect of the grinding is to change the layer structure carrier MgCl_2 into ~ 100 microcrystal along the weaker interlaminar layer, Sufficient specific surface, TiCl_4 up to the monolayer dispersion, TiCl_4 by Al-alkyl aluminum reduction Ti ~ (3 +) in the carrier surface was single-atom dispersion, can basically act as the active center, which is the source of high efficiency, MgCl_2 And TiCl_3 have a similar layered structure and Mg 2+ and Ti 3+ have similar radius and are the structural basis of MgCl 2 as a good carrier. The active components are monolayer dispersed and can basically act as an active center This “efficient mechanism” can be extended to other polyolefine efficient catalysts. The rate of polymerization of the active site and other structural mechanisms of efficient catalysts are also discussed.