Probing into morphology evolution of magnesiumethoxide particles as precursor of Ziegler-Nattacatalysts

Mg(OEt)2 with spherical morphology is one of the most important precursors for the preparation of industrialZiegler-Natta catalysts. In the present article, morphology evolution of Mg(OEt)2 particles is studied in the courseof the synthesis. The morphology of Mg(OEt)2 particles is observed throughout the process by SEM. The resultsshow that Mg(OEt)2 particles are formed through i) seed generation on Mg surfaces, ii) seed growth and isolationas independent particles, and iii) further growth and shaping into smoother and more spherical particles. The sizeof Mg sources greatly affects the rates of these processes to different extents. A larger size of Mg leads to slowerseed formation and growth, and detachment of clustered seeds, making the fnal particles larger and less spherical,respectively. The crystal growth of Mg(OEt)2 is also affected by the size of Mg sources, which in turn differentiatesthe pore size distribution to affect the catalyst composition and performance. Polyolefns J 3:47-57

Keywords:

Ziegler-Natta catalysts , magnesium ethoxide , morphology , polymerization , particle evolution