Self-stratifying epoxy/silicone coatings

International audienc

Self-stratifying coatings: A review

International audienc

Ru-Pyrochlores: Compositional Tuning for Electrochemical Stability as Cathode Materials for IT-SOFCs

International audienceUsing XRD, impedance spectroscopy, and XPS, it was shown that both Bi2Ru2O7 and Pb2Ru2O6.5, generally announced as attractive electrode materials for IT-SOFCs, chemically react with CGO. In addition, a never-mentioned time-instability under electrochemical measurements with YZS as electrolyte mediates the polarization tests. For Pb2Ru2O6.5, long time experiments (stabilization time > 900 h, previously to complementary electrochemical tests), yields strong increasing of the resistance polarization. Concerning Bi2Ru2O7, a partial transformation into Bi3Ru3O11 is observed after impedance measurements. The investigation of the Bi2−xMxRu2O7−δ (M = Sr, Pb) solid solutions was performed with the aim to improve the catalytic/electric properties. For low x values, it shows a time and chemical stabilization of the electrode/electrolyte cells, able to preserve high electrode performances of these materials. For higher substitution, the chemical/electrochemical instability reappears. According to our polarization measurements versus oxygen pressure and temperature in the so-called “stabilized” samples, the electrode performance appears limited by the diffusion of adsorbed oxygen on the triple point boundary. It is fully compatible with the metallic behavior checked in all the series

One pot flame retardant and weathering resistant coatings for plastics: a novel approach

International audienc

Crossed characterisation of polymer-layered silicate (PLS) nanocomposite morphology: TEM, X-ray diffraction, rheology and solid-state nuclear magnetic resonance measurements

As the nanocomposite properties dramatically depend on the dispersion state of the filler in the matrix, it is essential to develop technical methods to characterise the nanodispersion both qualitatively and quantitatively. In this study, complete characterisations of the nanodispersion of organomodified clays in polyamide 6, polypropylene and poly(butylene terephtalate) are presented and discussed using different analytical tools. All four characterisation methods have been evaluated experimentally. TEM has been used to qualitatively characterise the dispersion. As TEM picture might be not fully representative of the whole sample, many pictures have to be analysed to mirror the global repartition. XRD is particularly adapted to the study of intercalated morphology of nanocomposite since the distance between two platelets can be calculated but needs TEM to provide more complete conclusions. Melt rheology and solid-state NMR are bulk analyses. During the measurement the sample is representative of the material. Rheology is relatively simple to make measurements and to get semi-quantitative data. In connection with NMR, we can get quantitative measurements on the degree of nanodispersion in the nanocomposit