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Multifunctional self‐healing composites have great potential in several applications, i.e., from automotive to aerospace. This study examines the self‐healing behavior of carbon fiber reinforced composites by depositing jet‐spun cyclic olefin copolymer (COC) meshes on dry carbon fiber plies before lamination with epoxy resin (EP). Three different laminates were prepared, including neat EP/CF and two composites with 4 wt.% and 8 wt.% of COC in the form of a jet‐spun network as a healing agent. The introduction of COC mesh reduced flexural stress by 26% and interlaminar shear strength by 50%. Mode I interlaminar fracture toughness (GI) was evaluated and specimens were mended at 110°C by resistive heating generated by an electrical current flowing within the samples. The laminates containing 8 wt% COC reported a healing efficiency, evaluated as the ratio between the GI and as the ratio of the maximum load (PMAX) of virgin and healed samples, of 9.4% and 33.7%, respectively. Fractography analysis highlighted the poor adhesion between the COC mesh and EP matrix, and several COC microfibers were trapped inside the epoxy matrix, hindering their diffusion inside the crack zone, which limited the healing capability of the prepared laminates. [ABSTRACT FROM AUTHOR]

The elevated brittleness of commercial grades of poly(lactic acid) (PLA) may limit their use in several engineering applications. Therefore, the aim of this work is to develop a PLA‐based material possessing well‐balanced stiffness and toughness. Composites were prepared by blending PLA with increasing contents (from 10 to 30 wt%) of a thermoplastic polyurethane (TPU) and a fixed concentration (5 wt%) of carbon fibers (CFs), to tune the mechanical properties of the resulting materials. In order to increase the interfacial adhesion between CFs and polymeric phase, CFs were subjected to an acidic modification, by treating them in solution of H2SO4 and HNO3. The prepared composites were characterized from a chemical, rheological, morphological, and thermo‐mechanical point of view. Fourier transform infrared spectroscopy showed that the fiber surface reactivity was significantly enhanced by the acid treatment, with the introduction of reactive functional groups on CFs. Rheological and dynamic‐mechanical tests confirmed that the introduction of acid‐treated CFs implied strong fiber–matrix interactions. Thanks to the presence of the acid treated CFs, an important increase in tensile modulus and maximum stress was obtained for all the compositions. In particular, samples containing 10 wt% of TPU showed +74% tensile modulus and +43% maximum stress with respect to the unfilled blends. Moreover, the elongation at break of PLA was significantly improved (+81%) with the addition of 30 wt% of TPU. It was therefore demonstrated that the adopted approach could be effective for the preparation of novel PLA‐based materials with tailorable and well‐balanced properties that could find application in various technological fields. [ABSTRACT FROM AUTHOR]