Towards the design of a mixture of diether and succinate as an internal donor in a MgCl2-supported Ziegler–Natta catalyst

Abstract

Insight into the impact of mixed internal donors, comprising bis-methoxymethyl-fluorene (BMF) and 2,2-diisopropyl succinate (DIS), on the crystalline structure of MgCl₂ supported Ziegler–Natta catalysts is developed. The propylene polymerization performance of the catalysts is studied and compared with related single internal electron donor systems. A study of the crystalline structure of the catalysts reveals that an increase in the DIS content leads to a relatively higher amount of the α-form over the β-form in the catalyst matrix. The catalyst performance is explained through the coordination nature and composition of the internal donors. Molecular weight analysis shows that the molecular weight distribution of these systems is within the range 2.8–3.3. Meanwhile, in these systems an increase in the DIS content is conducive to improving not only the relative content but also the lamellar thickness of the polymer chains. A promising feature of the obtained results is that they provide guidelines for synthesizing desired polymer properties through a change in the mixture of internal donors in the catalysts.