Abstract
Taking inspiration from nature allows to engineer materials that possess improved performance, durability and reliability. For instance, living systems repair themselves spontaneously when their biological tissues are injured. Similarly, a material that self-heals when cracked or damaged has the potential to significantly augment its life-time and at the same reduce environmental impact (higher sustainability).
This work is focused on the fabrication of a fibre-reinforced composite, whose aggregating matrix is a thermosetting epoxy resin that is here demonstrated to possess self-healing capability. The composite is designed in such a way to follow the “Close Then Heal” strategy, as for human skin. The chemical and mechanical characterization of the material is discussed, first by studying the bare resin, and then by investigating self-healing of the carbon fiber composite once artificially damaged and re-healed. The study focuses in particular to the most critical failure mode of fibre-reinforced composites: i.e. delamination, which is known to be catastrophic. The results show that the composite self-repairs for a limited number of cycles and that the recovery of the mechanical properties, assessed by comparing the response of the composite before and after cyclic failures/repairs, decreases gradually with the subsequent cycles. The study also shows that the application of pressure allows to reach a more efficient repair, while the microscopic investigation highlights the great potential also in terms of morphological distribution of the fibers within the hosting matrix. The morphology of the re-healed samples is found to be fully recovered with respect to the initial undamaged samples.
