Nanocomposites flying high for lightning protection
When lightning strikes an aeroplane, the electricity travels through the aircraft's conductive skin and exits from the tail, for example. However, the introduction of advanced composite materials in modern aircraft structures presents special challenges because of their inherent low electrical conductivity. Overcoming these problems was the aim of the 'Development of nanofilled prepreg for aircraft composite structures' (CNMD) project, funded by the EU. The project used epoxy resins modified with carbon nanotubes as matrixes for composite materials with tailored electrical properties. The project team carried out a preliminary feasibility study on epoxy resins modified with carbon nanotubes. These project activities provided useful indications on the parameters for processing the pre-impregnated composite, or prepreg. Nanotubes were pre-mixed with the epoxy components in the system and then dispersed either by ultrasound or using three roll-milling methods. These prepregs were then used to manufacture a series of composite panels. CNMD consortium members used the panels to determine the processability as well as the mechanical and electric properties of the composites. By optimising the manufacturing parameters, they were able to produce defect-free, high-quality nano-modified panels. The project demonstrated that the modified material has improved properties, including enhanced electrical conductivity. An evaluation of a lightning strike by CNMD demonstrated that the modified panels also have improved resistance to lightning. Now completed, the project has proved the technology's potential for application in aircraft structures, and component manufacturers will now be able to fully exploit the benefits of nanocomposites. In addition, nano-modified materials have great potential for automotive, rail transport and wind turbine blades applications.
