Evidence of the Quasi‐Living Character of the ansa‐Zirconocene/MAO‐Catalyzed Copolymerization of Ethylene and Norbornene

The kinetics of the ethylene‐norbornene copolymerization, catalyzed by rac‐Et(Ind)₂ZrCl₂/MAO, 90%rac/10%meso‐Et(4,7‐Me₂Ind)₂ZrCl₂/MAO and rac‐H₂C(3‐tert‐BuInd)₂ZrCl₂/MAO was followed by sampling from the reaction mixture at fixed time intervals. Catalyst activity, copolymer composition and molar mass were studied as a function of time. The polymers showed an unusually low polydispersity and a significant increase in their molar mass with time, suggesting a quasi‐living polymerization.