Morphology and micromechanical behaviour of ethylene cycloolefin copolymers (COC)

Cyclic olefin copolymers (COC) of ethylene and different types of cyclic monomers were investigated in detail. In particular, the influence of the type and the content of cyclic monomers on the micromechanical deformation behaviour was studied using electron microscopy. Several deformation modes as fibrillated crazes, homogeneous deformation zones, shear-bands, and occasionally a combination of some of these deformation structures were observed in these materials. The different deformation modes are correlated with the mechanical properties. A tendency to an increase in brittleness with increasing cyclic monomer content was observed. COC with larger side chains in the cyclic monomer show a more ductile behaviour with the corresponding deformation structures than COC with norbornene.