Novel Thermal Coating for High-Speed Airplanes

In comparison to various other materials, carbon fiber, specifically carbon fiber reinforced polymers (CFRP) remains pre-eminent amongst other materials for use on aeronautical systems. Due to its high specific strength (strength-to-weight ratio), CFRP has been able to carry heavy loads while maintaining a lightweight build. This strength and weight efficiency has allowed for commercial airplanes such as the Airbus A350 and the Boeing-787 Dreamliner to greatly outperform common aluminum frame airplanes. Despite its extraordinary strength and light weight efficiency, when influenced by heat resulting from air resistance, CFRP is known to undergo serious degradation that would significantly decrease the effectiveness of the polymers. To prevent this degradation and maintain the strength of the CFRP, thermal protective layers (TPLs) are designed to shield the CFRP from heat exposure. This research is focused on the examination of the effectiveness of TPLs, that are hybrid compositions of epoxy resins and buckypaper (carbon nanotubes) for 3K 2 × 2 twill carbon-fiber, through experimental methods. Experimental thermal analysis of the CFRP is performed at 225 °C for hot plate testing and 650 °C for heat gun testing. The results show that the addition of buckypaper in the thermal protective layer seemed to detect nearly 48°C less heat on average of the four measured intervals in hot plate tests. From heat gun tests, moreover, it was clearly seen that the carbon fiber TPL that contains the epoxy and buckypaper is dominant in terms of heat dispersion. The anisotropic thermal transport property of nanostructured carbon is expected to spread heat accumulated in hot spots efficiently, preventing the heat from being propagated into the CFRP body material. In the near future, the authors will use analytical method and FEA simulations to explain this heat dissipation phenomena.