Smart electroactive self-repairable coating involving end-of-life aircraft prepregs by mechanical recycling

Abstract

The environmental impact of the Carbon Fiber Reinforced Polymers (CFRPs) industry, particularly due to waste generation during manufacturing and end-of-life phases, is compelling major industrial entities to reconsider a circular economy approach for their materials and to comply with emerging regulations. This study explores the potential of recycled carbon fibers (rCFs) derived from the mechanical recycling of prepreg waste. Mechanical recycling was selected for its cost-effectiveness and moderate environmental impact, recovering short rCFs with lengths below 200 μm. These rCFs, which retain excellent electrical properties, are incorporated into an epoxy matrix with Polycaprolactone (PCL) to create a multifunctional coating with self-healing capabilities. The resulting composite material exhibited significant improvements in electrical conductivity, achieving up to 16.50 S/m, and demonstrated effective Joule effect heating, exceeding 200 °C with 20 V applied for a composite containing 15 wt% rCF. The self-healing efficiency for surface cracks, activated by the Joule effect, reached 80–90 %, resulting in a 99 % reduction in energy consumption compared to conventional oven heating. Notably, the self-healing mechanism was characterized in real-time within a scanning electron microscope for the first time, providing a comprehensive evaluation of the process. This innovative coating offers promising applications in aviation for anti-icing, deicing, and maintenance reduction, as well as in residential settings as an energy-efficient floor heating solution. This research underscores the potential of mechanically recycled CFRPs to produce high-value, sustainable materials, promoting a circular economy and reducing the environmental footprint of the aeronautical sector.