Experimental investigation of the fire behaviour of a carbon-PEKK composite used for aeronautical applications

Composite materials used for aerospace applications are vulnerable when exposed to high temperatures. Therefore, the development and the using of these materials are strictly framed by aviation regulations where severe fireproof requirements must be accomplished. In the light of this, experimental research is of crucial importance in the understanding of the thermal behaviour of composites materials for aircraft parts, especially when they might be exposed to high-temperature or fire conditions. In this context, thermal degradation of the thermoplastic resin polyether-ketone-ketone (PEKK) with carbon reinforcement is studied. This composite belongs to the polyaryletherketone (PAEK) family, which is known for its high performances. The carbon-PEKK thermal behaviour is evaluated from small scale to medium by scale by means of thermogravimetric analysis, Differential scanning calorimetry, Py-GC-MS and cone calorimeter. The different experiments demonstrate the high thermal performance of the carbon-PEKK composite. Indeed, the latter does not present any decomposition below 500°C, as well as a low amount of volatiles emitted during the resin decomposition. The cone calorimeter experiments confirm the results obtained at small scale and demonstrate that the low yield of volatiles induces a low amount of heat release when exposed to a radiative heat flux. Moreover, the samples present a reduced temperature on the backward face. Finally, these results suggest that the carbon-PEKK might ensure the confinement of a fire as well as a limitation of the fire spread.