Mechanical properties of mendable composites containing self-healing thermoplastic agents

The tensile and compressive properties of mendable composites containing thermoplastic particles as self-healing agents are assessed in this paper. The effects of the type and concentration of thermoplastic healing agent on the mechanical properties of carbon fibre-epoxy composites were determined experimentally by mechanical testing and computationally using finite element analysis. The elastic modulus and failure stress of the mendable composites decreased at a linear rate with increasing weight fraction of thermoplastic agent in the epoxy matrix phase. Microstructural analysis revealed the thermoplastic agents thickened the polymer-rich layers between the plies, and this reduced the average fibre volume content of the mendable composite thereby lowering its mechanical properties. Restoration of the in-plane properties of mendable composites following healing of delamination damage using thermoplastic particles was also assessed. Healing partially restored the compressive modulus of the mendable composites, but had no healing effect on their compressive strength or tensile properties.