Preparation of Polyhedral Oligomeric Silsesquioxane-Supported Ziegler–Natta Catalyst and Its Application for Stereoselective Propylene Polymerization

Abstract

In this study, a polyhedral oligomeric silsesquioxane (POSS)-MgCl bisupported TiCl₄ catalyst was synthesized through the treatment of trisilanolisobutyl POSS with Grignard reagent, followed by anchoring TiCl₄. The resulting catalyst could catalyze the propylene polymerization with very high activity after activation by a cocatalyst. Meanwhile, it is noteworthy that, as the cage structure of POSS contains a silicone ether structure, the isotactic index of the obtained polypropylene (PP) exceeds 90%, even in the absence of an electron donor. Additionally, because of the uniform dispersion of POSS in the PP matrix during polymerization and good interfacial compatibility, the obtained PP/POSS nanocomposites possess not only excellent thermal stability but also excellent mechanical properties. Therefore, a high-activity catalytic propylene stereoselective polymerization catalyst was developed and provided a feasible method for the fabrication of high-performance PP/POSS nanocomposites.