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Epoxy resins containing Diels-Alder furan and maleimide moieties are presented with the capability to self-heal after exposure to an external heat source. A conventional epoxy amine system has been combined with furfuryl and maleimide functional groups in a two-step process, to avoid major sidereactions, and the concentration of a thermo-reversibly binding cross-linker was considered to balance thermoset and thermoplastic behaviours, and the subsequent self-healing performance.In the context of self-repair technologies an inbuilt 'intrinsic' self-healing system is deemed favourable as the healing agent can be placed in known 'hot spot' regions (i.e. skin-stringer run outs, ply drops and around drilled holes) where operational damage predominately occurs in load bearing aerospace structures. In this study, the mechanical and self-healing performance of furan functionalised epoxy resins containing varying amounts (10, 20, 30 or 40 pph) of bismaleimide were investigated using a bulk epoxy polymer tapered double cantilever beam (TDCB) test specimen geometry. Two forms, a thin film and a bulk material, were evaluated to account for future integration methods into fibre reinforced polymer (FRP) composites. The highest healing efficiency, with respect to the obtained initial load value, was observed from the 20 pph bulk material derivative. The polymers were successful in achieving consistent multiple (three) healing cycles when heated at 150 °C for 5 minutes.This novel investigated Diels-Alder material exhibits favourable processing characteristics for FRP composites as preliminary studies have shown successful coextrution with reinforcing fibres to form free standing films and dry fibre impregnation.

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A facile two‐step process is developed to obtain polyester urethanes that contain various concentrations of thermoreversible Diels–Alder adduct–based bonds for the development of adhesives. Besides linear systems thermoreversible networks have been included in the study. The reactions are verified using IR‐spectroscopy and gel permeation chromatography analysis. The material properties are characterized with solvent exposure tests, dynamic scanning calorimetry, microindentation and rheology and the potential for application as adhesives is tested with an elcometer. Material properties have been found highly tunable for the system, and high adhesive strengths (off‐scale) are found for polyester urethanes that are doped with an intermediate level Diels–Alder functional groups. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44972.