Structure–performance relationship in Ziegler–Natta olefin polymerization with novel core–shell MgO/MgCl2/TiCl4 catalysts

The impact of support architectures on the olefin polymerization performance of heterogeneous Ziegler–Natta catalysts has been scarcely understood due to the complexity of pore system and the fragmentation-induced structural changes during polymerization. In this communication, a series of novel core–shell MgO/MgCl2/TiCl4 catalysts were synthesized by utilizing poreless single-crystal MgO nanoparticles as a non-fragmentable core material. Employing these catalysts, we have successfully established a structure–performance relationship (SPR) that the propylene polymerization activity is perfectly proportional to the catalyst surface area for the first time. On the other hand, polymer properties were found to be decided by active site natures independently of the surface area.

Graphical abstractStructure–performance relationship between the catalyst surface area and olefin polymerization activity was firstly established in heterogeneous Ziegler–Natta polymerization by utilizing novel core–shell MgO/MgCl2/TiCl4 catalysts.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Core-shell MgO/MgCl2/TiCl4 catalysts as model Ziegler-Natta catalysts. ► First structure-performance relationship in Ziegler-Natta olefin polymerization. ► Single-crystal MgO core thinly covered by MgCl2/TiCl4 catalytic components. ► The MgO/MgCl2/TiCl4 catalysts were poreless and non-fragmentable. ► Proportional relation between surface area and propylene polymerization activity.