The toughening of epoxy resins with thermoplastics: 1. Trifunctional epoxy resin-polyetherimide blends

A series of blends has been prepared by adding a polyetherimide, in varying proportions, to a trifunctional epoxy resin, triglycidylparaaminophenol, cured with 4,4′-diaminodiphenylsulphone. All the materials showed two-phase morphology when characterized by dynamic mechanical thermal analysis and scanning electron microscopy. Addition of the thermoplastic resulted in improved fracture properties (K1C and G1C), as measured by three-point bending experiments, although no obvious correlation with blend morphology was observed.