Preparation Of Ethylene Slurry Polymerization Ziegler-Natta Catalysts And Their Polymerization Performance Study

This thesis is based on the study of MgCl₂support titanium Ziegler-Natta catalysts,andtetraethyl orthosilicat(eTEOS)which is a kind of electron donor compound was added intotraditional titanium Ziegler-Natta catalysts. A new and efficient magnesium chloride catalystsupported on titanium was prepared,and its main purpose is to improve the too high contentpowder and oligomer on its plant applications,to tackle the problems such as shortproduction cycle,easy to plug devices etc. on the premise of maintaining outstandingaggregate performance of traditional titanium Ziegler-Natta catalysts,in order to meet theneeds of the polymerization process of innovation and the high-level of performance ofmarket polyethylene products.In this thesis, the new and efficient preparation process of titanium catalyst supportedon MgCl₂was studied systematically, investigating the factors of polymerizationtemperature, Al/Ti mole ratio,hydrogen and1-butene amount on the influence of catalystperformance. The morphology and pore structure of the catalyst were characterized by SEM,BET, and DSC,¹³C-NMR are used to study the structure and properties of the polymer. Theresult showed that the new type of catalyst that added into electron donor obtained highcatalytic activity and high specific surface area. Under the polymerization conditions ofpolymerization temperature of80℃, Al/Ti molar ratio of120and P_H2/P_C2H4=0.62, thepolymer obtained excellent characteristics that were high bulk density (a maximum of0.35g/cm³), little content of tiny powder (a minimum of0.43%) and better particlesmorphology. The result indicated that the addition of electron donor improved thesensitivity of the catalytic hydrogen transfer and copolymerization performance effectively,reduced the content of tiny powder and oligomers in the polymer, in favor of its applicationin industrial installations.