Copolymerization of olefins with Kaminsky‐Sinn‐type catalysts

Abstract

Abstract Copolymerizations of ethylene with propene, ethylene with 1‐hexene and propene with 1‐hexene were performed at 40°C under atmospheric using three kinds of Kaminsky‐Sinn‐type catalysts which differ in stereospecificity: Cp 2 ZrCl 2 ‐methylaluminoxane (MAO) (aspecific); Et[IndH 4 ] 2 ZrCl 2 ‐MAO (isopecific); i ‐Pr(Cp)(Flu)ZrCl 2 ‐MAO (syndiospecific). The 13 C NMR analysis of copolymers showed that the incorporation of higher olefins decreases in the following order: i ‐Pr(Cp)(Flu)ZrCl 2 ‐MAO > Et[IndH 4 ] 2 ZrCl 2 ‐MAO > Cp 2 ZrCl 2 ‐MAO, and that stereospecificity is retained even in the copolymerization. The product of monomer reactivity ratios ( r 1 · r 2 ) indicates that poly(propene‐ co ‐1‐hexene) is a statistically random copolymer whereas both poly(ethylene‐ co ‐propene) and poly(ethylene‐ co ‐1‐hexene) have somewhat alternating character regardless of catalyst stereospecificity.