The self-reinforcing effect of Nylon 6,6 nano-fibres on CFRP laminates subjected to low velocity impact

This work investigates the mechanical properties of CFR-epoxy laminates interleaved with electrospun Nylon 6,6 nano-fibres. The main goal is to investigate the interaction between the nanofibrous mats interleaved into a laminate and their influence on the property of the whole body and in particular their reinforcing effect. To achieve the purpose, an experimental programme is developed and carried out. Two different nanomodified configurations are suggested and tested together with virgin specimens. All the specimens are subjected to static and dynamic tests to assess their stiffness, harmonic frequencies and damping. The experiments are repeated before and after low velocity impacts in order to investigate the effect of nano-fibres to static and dynamic properties when the laminates are impacted. SEM images of fractured surfaces and the mechanical results were used to attest the benefits brought by the presence of the nanointerleave. Results show that the interaction between the resin and the nano-fibre is the key feature of the reinforcement mechanism. When the resin is undamaged the friction with Nylon increases the damping ratio of nanomodified specimens with respect to that of virgin ones. When the matrix is damaged a fibre-bridging mechanism is revealed, and the nano-fibres increase the damage tolerance of laminates.