a b s t r a c tBlends of commercial epoxy monomer with a 4,4 0 -diaminodiphenylsulfone hardener and poly(e-caprolactone) (PCL) were evaluated for their potential as a self-healing matrix for fiber-reinforced composites, based on their room temperature toughness and stiffness and their capacity for healing when subjected to a moderate heating cycle. Analysis of the microstructure and thermal properties of the blends indicated three types of morphology to result from polymerization-induced phase separation during cure, depending on the PCL content, including an interconnected particulate epoxy phase and a co-continuous PCL phase above 23 vol% PCL. While the mechanical performance diminished with increasing PCL content, toughness recovery after healing at 150°C for 30 min strongly increased. Blends with 25 vol% PCL showed a healing efficiency in excess of 70%, while retaining suitable room-temperature mechanical properties (a tensile modulus of 1.5 GPa and a tensile strength of about 20 MPa), and were concluded to be promising candidates for self-healing composites.
Vacuum Assisted Resin Infusion Molding (VARIM) with low vacuum pressure difference was used to manufacture woven glass fibre-reinforced epoxy resin plates, with a fibre volume fraction of approx. 50 vol% and containing ethyl phenylacetate (EPA)-filled capsules for self-healing purposes. Capsules were introduced by functionalising the fabrics through manual dispersion. We investigated the capability of autonomously healing delaminations induced by static loading in Mode I and II. Healing did not take place for composite samples; this was attributed to the presence of bare fibres on the crack plane and to the reduction of EPA diffusion into the matrix in the presence of fibres both of which hinder the swelling mechanism responsible for healing the cracks.
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