Thermal and dynamic mechanical behavior of ethylene/norbornene copolymers with medium norbornene contents

A range of ethylene/norbornene copolymers were synthesized using the commercially available rac-Et(Ind)(2)ZrCl2 metallocene catalyst. A large window of norbornene contents, between 30 and 55 mol % was used to facilitate the interpretation of the results. The polymers were characterized by means of wide-angle X-ray scattering, differential scanning calorimetry, and dynamic mechanical thermal analysis. The X-ray diffractograms showed two amorphous halos, the low-angle one increasing in the intensity with norbornene content. Calorimetric and dynamic mechanical results led to a linear relation between the glass transition temperature and the norbornene content. (C) 2001 John Wiley & Sons, Inc.