Molecular weights cycloolefin copolymers

Depending on the application, different demands are placed on the melt viscosity of the polymer. For injection molding applications, lower melt viscosities are required than for extrusion applications. For a given comonomer composition and processing temperature, the melt viscosity of the cycloolefin copolymers increases with the mean molecular weight. 

E-N copolymers made by single-site catalysts are characterized by narrow molecular weight distributions, which make technical processing easier. The first commercial E-N copolymer products by early transition metal catalysts are already available. In contrast, late transition metal catalysts, which are more tolerant to polar functional groups, need further developments to be efficiently used in olefin-cycloolefin copolymerizations. 

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