Influence of MIL-53 on the catalytic performance of metallocene in propylene polymerization

Abstract

In this study, we investigate the application of metal-organic frameworks (MOFs) as a support for metallocene catalysts in the polymerization of propylene. MOFs such as MIL-53 and other conventional supports, SBA-15 and SiO₂, were employed to immobilize the Me₂Si(2-Me-4-PhInd)₂ZrCl₂ catalyst activated with methylaluminoxane (MAO). The effects of the physicochemical properties of these supports on catalytic performance and polymer properties were investigated. MIL-53, characterized by its channel structure, facilitated higher molecular weight polypropylene production and exhibited double the catalytic activity of SBA-15 and SiO₂ supports. The MIL-53/MAO/Me₂Si(2-Me-4-PhInd)₂ZrCl₂ catalyst also demonstrated higher comonomer incorporation and lower polymer melting points. The higher activity, elevated molecular weight, and increased reactivity towards 1-hexene of the MIL-53/MAO/Me₂Si(2-Me-4-PhInd)₂ZrCl₂ catalyst are attributed to the electronic and steric effects of MIL-53. This study underscores the significant role of MOF structure in influencing polymerization behavior and highlights the potential of MOF-supported catalysts for tailored polymer properties.