ELECTRON DONORS IN ZIEGLER-NATTA CATALYSTS FOR PROPYLENE POLYMERIZATION AND ITS MECHANISM

Electron donors in Ziegler-Natta catalysts have very important effects on the improvement of stereoregularity for Polypropylene, but the mechanism behind the effects is not understood clearly, which results in some difficulty on the development and application of new electron donor, in recent years, the researches on effect mechanism and to seek new electron donors have been carried out very popularly, which also is the direction to improve Ziegler-Natta catalysts. In this paper, the progress in development of new electron donors, such as the diether as internal donor and alkoxysilane as external donor, was reviewed, also the effects of electron donor on stereoregularity of PP were introduced, and some general accepted conclusions about the mechanism were summarized, in the end, the development in this area was prospected.