Polymerization of methyl acrylate by a 2,6-bis(2-benzimidazyl)pyridine zirconium dichloride/MAO catalyst system

Abstract

A novel non-metallocene Zr(IV) complex bearing a bianionic form of the ligand 2,6-bis(2-benzimidazolyl)pyridine is synthesized. This Zr complex is an active catalyst for the polymerization of MA via coordination polymerization in the presence of methylaluminoxane MAO. The activity and MWD are increased as the polymerization temperature increases. The maximum activity is observed at Al/Zr molar ratio of 100 and the deactivation is shown above 100, resulting from an inactive bimetallic complex between catalyst and free TMA presented in MAO. Decrease in MWD is observed with higher MAO concentration due to its role in chain transfer during the chain propagation.