Summary: The evolution of the morphologies in blends of epoxy/4,4′‐methylenebis(2,6‐dimethylaniline)/polyethersulfone was followed by time‐resolved light scattering, optical microscopy and scanning electron microscopy. The results suggest that, once the diffusion of epoxy molecules cannot follow the geometrical growth, a secondary phase separation occurs, even in the droplet morphology, in which the size of the epoxy‐rich domain grows as usual. The viscoelastic effect of polyethersulfone is also discussed.
Development of morphologies followed by OM: bicontinuous phase separation in the PES‐15.9 blend cured at 140 °C after 80 s.
