Ethylene--norbornene Copolymerization Using a Dual Catalyst System in the Presence of a Chain Transfer Agent.

Ethylene--norbornene copolymers were synthesized by a dual catalyst system at three concentrations of norbornene in the feed and variable amounts of ZnEt₂, as a possible chain transfer agent. The dual catalyst system consists of two -metallocenes, isopropyliden(ηcyclopentadienyl)(η⁵-indenyl)zirconium dichloride () and isopropyliden(η⁵-3-methylcyclopentadienyl)(η⁵-fluorenyl)zirconium dichloride (), activated with dimethylanilinium tetrakis(pentafluorophenyl)borate, in presence of TIBA. Values of norbornene content, molecular mass, glass transition temperature, and reactivity ratios and of copolymers prepared in the presence of + are intermediate between those of reference copolymers.