Sustainable rosin acid ester as internal electron donors in Ziegler-Natta catalysts for synthesis of isotactic polypropylene with high melt flow rate

In this contribution, novel bio-derived rosin acid ester compounds have been developed and used as internal electron donors to prepare MgCl2 supported titanium catalysts for propylene polymerization. The results of the polymerization showed that tri-n-amyl maleate, triiso-amyl maleate and tri-n-heptyl maleate as internal electron donors in Ziegler-Natta catalysts all have high polymerization activity and stereoregularity. In particular, the Ziegler-Natta catalyst with tri-n-amyl maleate as the internal electron donor has the highest activity (up to 33.4 kgPP·gCat−1·h−1) for propylene polymerization and the isotacticity of polypropylene is as high as 96.8% determined by 13C NMR. Simultaneously, the obtained polypropylene with a relatively broad molecular weight distribution of 9.0 and melt flow rate of 160.3 g/10 min, which is beneficial to processing and has practical industrial application value when used as the basic material of melt blown cloth for medical mask.