Structures of polyethylene and copolymers of ethylene with 1‐octene and oligoethylene produced with the Cp₂ZrCl₂ and [(C₅Me₄)SiMe₂N(t‐Bu)]TiCl₂ catalysts

Abstract

Abstract Polymerization of ethylene and copolymerizations of ethylene with 1‐octene and oligoethylene having a vinyl end group were conducted with Cp 2 ZrCl 2 and [(C 5 Me 4 )SiMe 2 N(t‐Bu)]TiCl 2 a as catalysts, and the structures of the resulting polymers were analyzed in detail. The Cp 2 ZrCl 2 catalyst combined with methylalumoxane (MAO) gives polyethylene with vinyl, vinylidene and trans ‐vinylene groups. The use of Al(iC 4 H 9 ) 3 /(C 6 H 5 ) 3 C · B(C 6 F 5 ) 4 as cocatalyst produces polyethylene predominantly containing trans ‐vinylene groups. Polyethylene with vinyl end groups was obtained selectively with [(C 5 Me 4 )SiMe 2 N(t‐Bu)]TiCl 2 MAO as catalyst. The types and contents of CC double bonds in polyethylene markedly depend upon the metallocene compound as well as as the cocatalyst. In the copolymerizations the [(C 5 Me 4 )SiMe 2 N(t‐Bu)]TiCl 2 MAO catalyst system, on the other hand, gives poly[ethylene‐ co ‐(1‐octene)] with a high content of 1‐octene and a polyethylene containing an appreciable amount of long‐side‐chain oligoethylene.