Ethylene–hexene copolymerization by heterogeneous and homogeneous Ziegler–Natta catalysts and the “comonomer” effect

Abstract

Abstract Homopolymerization of ethylene and 1‐hexene and their copolymerizations were compared to investigate the influence of α‐olefin on the enhancement of ethylene polymerization rate ( R p ), which is often referred to as the “comonomer” effect. With the two homogeneous Ziegler–Natta catalysts, Et[Ind] 2 ZrCl 2 /MAO and (π‐C 5 H 5 ) 2 ZrCl 2 /MAO (MAO = methylaluminoxane), hexene causes reduction of R p —in other words a negative “comonomer” effect. In the case of the high activity MgCl 2 supported TiCl 3 catalysts there is a slight positive “comonomer” effect; the R p increases by 25 to 70% with the addition of 15 mol % of hexene. The “comonomer” effects in there catalyst systems are much smaller than that observed for the classical TiCl 3 catalyst. © 1993 John Wiley & Sons, Inc.