Mechanistic study on the effects of co-catalyst on ethylene polymerization over supported vanadocene catalyst

In this work, fundamental insight into the multifaceted role of co-catalyst in activation, propagation, and chain exchange of vanadocene in the immobilized single-site olefin polymerization catalyst has been obtained. The kinetics were followed for various Al/V ratios, at the same polymerization temperature with aluminium diethyl monochloride (DEAC) or triisobutylaluminium (TIBA) as co-catalyst. The results put forward a plausible deactivation reaction path of the catalyst for aluminium diethyl monochloride (DEAC) with irregular morphology of polyethylene particle due to the interaction between halogen atom and vanadium atom. This experimental set of data is supported by a computational investigation at the DFT level that rationalizes specific effects in the presence of co-catalyst at the molecular scale. This joint investigation offers a basic understanding for further catalyst developments in the field of supported metallocene catalyst for olefin polymerization.