Effect of active-site density on ethylene polymerization by a series of side-chain functionalised polynorbornene supported half-metallocene catalysts

Abstract

In this research, we attempt to develop soluble polynorbornene (PNB) supported half-metallocene catalysts with different active site density to embody catalytic multifunctionality in ethylene polymerization.  For this purpose, we have synthesized a series of PNB bearing different contents of ancillary donor ligands at side chain by Grubbs ring opening metathesis polymerization and used as supports for a half-metallocene catalyst (e.g. Cp*TiCl₃). Such supported catalysts equip well-defined characteristics in terms of active-site design analogous to the molecular catalyst as well as controlled active-site density in a random coil of a single polymer chain whose size is defined by the Flory radius.