Research Progresses in Internal and External Electron Donors for Propylene Polymerization Catalyzed by Ziegler-Natta Systems

The progresses in the internal electron donors and external electron donors for propylene polymerization with Ziegler-Natta catalysts were reviewed. The mechanisms of the internal electron donors and external electron donors used for propylene polymerization,and structure of the active sites and the catalytic kinetics of Ziegler-Natta catalysts were explored. What is more,the effects of the external electron donors on the catalyst activity,the stereo-regularity of the product polypropylene and its molecular weight distribution,the crystallization properties,and the isotactic sequence distribution were discussed.