Chemically induced phase separated morphologies in epoxy resin‐hyperbranched polymer blends

The morphology build‐up in toughened epoxy blends using reactive hyperbranched dendritic polymers (HBP) and amine‐cured epoxy resins has been investigated in the present work. By changing the processing conditions or the surface chemistry of the modifier, very different morphologies can be obtained, ranging from homogeneous blends to coarse two‐phase systems. The morphology characterised by electron and optical microscopy has been interpreted combining constitutive equations for phase separation and thermodynamic modelling of phase interactions. The latter model, based on the Flory‐Huggins lattice theory, was modified in order to take into account the addition reactivity of the HBP modifiers. This approach proved successful and can be used as a tool for final morphology prediction in any reactive blend formulation.