Post fire behavior of carbon fibers Polyphenylene Sulfide- and epoxy-based laminates for aeronautical applications: A comparative study

Through the comparison of two carbon fiber-reinforced polymers (Epoxy and Polyphenylene Sulfide - PPS), this work was aimed at investigating the influence of different fire conditions on the high temperature tensile mechanical behavior. In order to better understand the influence of matrix nature on post-fire properties, the fiber - or matrix-dominated mechanical responses of laminates have been investigated by means of quasi-isotropic or angle-ply stacking sequences. Compared to carbon/PPS laminates, the mechanical properties of carbon/Epoxy laminates are higher in the virgin state (no prior fire exposure). The analysis of the post fire tensile properties shows that prior severe fire exposures are more detrimental to carbon/Epoxy than to carbon/PPS laminates. Although the PPS matrix behavior is highly ductile at a test temperature higher than glass transition temperature, it clearly appears that the decrease in the tensile properties laminates of PPS-based composites is much slower than the one observed in carbon/Epoxy laminates subjected to severe prior fire conditions. Provided the heat flux is high enough to lead to the outset of pyrolysis, PPS-based composites yield higher amounts of char, whose formation retains the structural integrity of fire-damaged composites.