High-performance conductive thermoplastic composites poly(ether ketone ketone) (PEKK)/silver nanowires were elaborated by melt blending. Silver nanowires (AgNWs) with high aspect ratio (ξ~220) were elaborated through the polyol process in presence of poly(vinyl pyrrolidone) (PVP) and ethylene glycol. Scanning electron microscopy observations of nanowires were performed after an adapted cleaning process. The dispersion of NWs in the polymeric matrix was evaluated. A very low percolation threshold of 0.6 vol% was obtained. Electrical conductivity values obtained above the percolation threshold were among the highest measured for low-filled conductive polymer composites. The influence of AgNWs on the PEKK matrix has been investigated by differential scanning calorimetry and dynamic mechanical analyses. It is important to note that thermal and dynamic mechanical performances of the polymeric matrix were preserved in composites.

Poly ether ketone ketone (PEKK) with different proportion of meta phenyl links were investigated by combining differential scanning calorimetry and dynamic mechanical analysis. The influence of the Terephthalyl/Isophthalyl isomers (T/I) ratio on the vitreous phase is mild, the shift of the glass transition is limited to a few degrees and the vitreous G′ is only sensitive to the content of the crystalline phase. Contrarily, the increase of meta isomers is responsible for a significant decrease of the melting temperature (Tm) by 60 °C, which considerably facilitates processing. The modification of interchain interactions in the crystalline phase might be implied. A series of thermal protocols evidenced that the difference of crystallization behavior is also dependent upon the T/I isomer ratio. A time and temperature dependence of annealing on the double melting behavior of PEKK was observed. Regarding the mechanical behavior, the observed reinforcing effect due to the crystalline phase was more prominent in the rubbery state than in the glassy state. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43396.

New multifunctional composites with high through-thickness electrical conductivity were elaborated with carbon fiber (CF) reinforced PEKK filled with silver nanowires (AgNWs). Composites were fabricated by film stacking at high temperature for the first series of samples and by powder impregnation for the second series. Morphological analysis of composites was performed by scanning electron microscopy (SEM) in order to check impregnation quality of carbon fibers and dispersion of AgNWs across the ply. Electrical conductivity was measured in the out-of-plane direction of laminates and recorded as a function of the volume fraction of silver nanowires. It was observed that the presence of small fractions of AgNWs (~1.5 vol%) within the carbon fiber reinforced PEKK increased the transverse conductivity of non-filled CF/PEKK laminates by at least 3 orders of magnitude. The maximum conductivity achieved by laminates is 250 S m À1. These new multifunctional composites may be used as structural high performance composites for electromagnetic shielding, or lightning strike protection.