A series of tough thermosetting resins based on the incorporation of amine-terminated poly(aryl ether ketone) oligomeric derivatives into commercial epoxy/amine resins, through a solventless process, have been evaluated. It is shown that when the amine-terminated oligomer is loaded at a level sufficient to form a material consisting of a lightly crosslinked thermoplastic continuous phase with epoxy/amine-rich inclusions, the fracture energy of the system increases by 350-750%, with either no loss or a slight increase in modulus, with respect to the unmodified commercial epoxy/amine resin, while possessing glass transition temperatures greater than the neat thermoplastic material. These tough resins are processable by conventional thermoset technology, as the system is initially a miscible low viscosity ternary melt consisting of a commercial epoxy, an amine-terminated oligomeric modifier, and an amine curing agent. Room temperature B-stage tack and drape is also maintained to allow for conventional prepreg lay-up procedures. The toughest systems combine the toughness characteristics of thermoplastic systems with the processing characteristics of thermosetting systems into a unique hybrid material. Phase separation occurs with curing and results in a lightly-crosslinked thermoplastic-rich phase and a highly-crosslinked epoxy/amine-rich phase. The thermal and mechanical properties are shown to be dependent on the morphology of the system which is determined by the loading level of oligomer for a given curing cycle. Three morphologically distinct systems are discussed. The synthesis, processing, solvent, thermal and mechanical properties of resins formulated with amine-terminated tertiary-butylhdroquinone, methylhydroquinone and bisphenol A based poly(aryl ether ketone) oligomers with various commercial epoxy resins are reported, and the properties are related to the observed phase separated morphology. The material represent conventionally processable high performance thermosetting resins with significantly increased fracture energies and equivalent moduli, with respect to the unmodified materials.
