Miscibility of binary blends of ethylene/norbornene copolymers: Comparison to a lattice cluster theory

The mutual miscibility of five binary ethylene/norbornene copolymers of the NxE1−x/NyE1−y type where x and y represent the norbornene content in the first and second copolymers, respectively (with x/y of 0.36/0.52, 0.36/0.56, 0.36/0.62, 0.46/0.60 and 0.46/0.66), in five different compositions was studied by rheology and differential scanning calorimetry. Most of the blends do not obey the principle of time–temperature superposition, i.e., they can be considered as thermorheologically complex, and hence immiscible. The experimental data from rheology were compared to a recent lattice cluster theory. The theoretical miscibility diagram correctly predicts the experimental cases for most blend compositions except for the very asymmetric compositions.