| Abstract
| - The molecular weights of ethene−norbornene copolymers, produced with various metallocene− and amidocyclopentadienyl−methylaluminoxane (MAO) catalysts, have been determined by high-temperature gel-permeation chromatography: with one exception, increasing molecular weights werefound with an increasing norbornene content in the copolymer. This observation is due to the fact thatthe β-hydride elimination process is not possible in the case of norbornene, because of special stericconditions of the cis-2,3-exo inserted norbornene; other possible termination reactions are discussed,considering the specialties of the norbornene. The effect of the catalyst structure on the molecular weightsis discussed in terms of steric and electronic factors of the different ligands: sterically less hinderedligands produce ethene−norbornene copolymers with relatively low molecular weights; ligands with alarger extension and electron-pushing effect such as the fluorenyl ligand, induced the formation of highmolecular weights. Additional alkyl groups at the indenyl or fluorenyl ligand increased the molecularweights additionally.
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