Development of a new generation of composites with Self-responsive functions: Self-sensing, Self-heating and Self-curing

This contribution deals with the design of composites having integrated self-responsive functionalities based on nanostructured forms of carbon, such as multi-wall carbon nanotubes and expanded graphite. In particular, the study focuses on three different smart functions strongly desired in the field of aeronautical materials: self-sensing, self-curing and smart thermal management. These responsive functions are based on two physical phenomena: the piezoresistivity (changes in the electrical resistivity of the composites resulting from mechanically applied strains) and the Joule effect (heat generated by the current flow through the composite). In the first case, the adopted approach allows the detection of micro-damages in the materials that a visual inspection is unable to detect. In the second case, the heat generated through the joule effect allows avoiding the ice growth on the most vulnerable parts of the aircraft. In the third case, the heat generated through the joule effect in the uncured filled resin is exploited to promote polymerization reactions of the resin (electro-curing). The results evidence that this last methodology can be really very effective, highlighting different advantages with respect to the polymerization of the resin in an oven or autoclave. It is a save-energy process that allows a higher curing degree and as a consequence a better mechanical performance with respect to traditional curing processes.