Thermomechanical and morphological properties of epoxy resins modified with functionalized hyperbranched polyester

Thermomechanical and morphological properties of blends of epoxy monomers and hydroxyl and epoxy functionalized hyperbranched polyesters have been studied. Different properties of the blends were found by changing the cure cycles (a precure step followed by a postcure at higher temperature). All the blends showed phase separation with a particulate morphology. Through the addition of the hydroxyl-ended modifiers, rather than the epoxy-ended, an increase of the viscosity and of the reactivity of the uncured blends was obtained. The blends containing the epoxy functionalized polymer showed some liquid-liquid transitions in the rheological traces, probably because of the phase separation phenomena.