Copolymerization of ethylene with norbornene or 1-octene using supported ionic liquid systems

Abstract

Copolymerization of ethylene with norbornene (E/NB) and ethylene with 1-octene (E/Oct) is performed using supported ionic liquid (SIL) systems, in which metallocene (Cp2VCl2) or post-metallocene [VCl2(salenCl2)] vanadium catalysts are immobilized in pyridinium chloroaluminate ionic liquid supported on silica. The studied SIL catalysts show higher activities as well as stability than their non-supported analogues. In addition, higher activities and better comonomer incorporation are observed for norbornene (above 30 mol%). The comonomer incorporation has considerable influence on copolymer molecular weight (Mw), melting temperature, crystallinity degree, and microstructure of the copolymers. Molecular-weight distribution is relatively narrow (1.5 ≤ Mw/Mn ≤ 3.0), which indicates the presence of single-site catalyst systems.