New polymers by copolymerization of ethylene and norbornene with metallocene catalysts

To increase the thermal stability of metallocene-methylaluminoxane catalysts. pentalene bridged zirconocenes and a constrained geometry catalyst were used for the copolymerisation of ethene and norbomene. The constrained geometry catalyst is stable in solution up to 90 degreesC. Surprisingly the molecular weight of the copolymers increases with higher incorporation rates of norbomene. Glass transition temperatures of 120 degreesC are reached. The microstructure of the cyclic olefin copolymers material is more alternating.