Graphene and carbon black have been dispersed in a high performance thermoplastic polymer, the poly(ether ketone ketone), to improve its electrical conductivity. The dispersion of graphene has a significant influence on the percolation threshold. A simple exfoliation protocol to obtain graphene monolayers has led to a significant decrease of the percolation threshold from 4.2 to 1. 9 vol%. To the best of our knowledge, it is one of the lowest percolation values for unfunctionalized graphene dispersed by melt blending in a high performance thermo plastic matrix. The conductivity value above the percolation threshold (1.2 S•m-i) means that graphene was not degraded during the elaboration process. Below the percolation threshold, Maxwell-Wagner-Sillars phenomenon increases the dielectric permittivity from 2.7 to 210 for PEKK/6 vol% graphene at 180 °C and 1 Hz. Dynamic mechanical analyses have shown that mechanical moduli were not significantly modified by conductive particles until 6 vol%.

a b s t r a c tA model poly-epoxy surface formed by the reaction of DGEBA and EDA is studied by the combination of experiments and DFT calculations. A special synthesis protocol is presented leading to the formation of a surface that is smooth (S a < 1 nm), chemically homogeneous, and that presents a low-defect density (0.21 m −2 ), as shown by AFM characterizations. Then, XPS is used for the determination of the elemental and functional groups' surface composition. DFT allows the identification and assignment of individual bonds contributions to the experimental 1s core-level peaks. Overall, we demonstrate that such a model sample is perfectly suitable for a use as a template for the study of poly-epoxy surface functionalization.

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