Copolymerization of ethylene and 1-decene by metallocenes: Direct comparison of Me2C(Cp)(Flu)ZrMe2 with Et(Cp)(Flu)ZrMe2

Abstract

Copolymerizations of ethylene with 1-decene have been carried out by using two syndiospecific metallocenes synthesized by modifying the bridge: highly syndiospecific isopropylidene(1-eta (5)-cyclopentadienyl)(1-eta (5)-fluorenyl)-dimethylzirconium (Me2C(CP)(Flu)ZrMe2, 1) and less syndiospecific (1-fluorenyl-2-cyclopentadienylethane) -dimethylzirconium (Et(Cp)(Flu)ZrMe2, 2), in the presence of [Ph3C][B(C6F5)(4)] as a cocatalyst. The ethano bridged 2 compound of smaller dihedral angle showed much higher activity than I compound. The catalytic activities of the two compounds were enhanced about twice when a suitable amount of 1-decene comonomer is present in the feed. The compound IL showed better comonomer reactivity than 2. The properties (T-m, density, and crystallinity) of copolymers seem not to be affected by the type of bridge of the metallocenes, and mainly depend on 1-decene content in the copolymer.