Authors:A. Squali, L. Montagne, P. Vast, G. Palavit and J. M. Buisine
By thermobarometric analysis, we have investigated gels and coacervates of polyphosphates systems (x MO-y P2O5-z CaO-n H2O, whereM=Na or Mg) and studied their physico-chemical transformations until 1000 bars. In every case, the same general shape is obtained for the thermobarograms. A strong pressure increment is first observed bounded to the expansion of the sample under temperature effect. Then, between 100 and 110‡C, a free water release is detected by an important and progressive decrement of pressure issue from a strong volume decrement. At higher temperature, the hydrolysis of the systems is turned into pressure increments. Such experiments are the first showing that, by thermobarometric analysis, physico-chemical transformations can be easily studied. Moreover, for the first time, a negative volume change at a transformation obtained by increasing the temperature has been able to be observed by thermobarometric analysis.
Authors:J. B.Nagy, J. N. Coleman, A. Fonseca, A. Destrée, Z. Mekhalif, N. Moreau, L. Vast and J. Delhalle
Organic polymers -
carbon nanotubes nanocomposites are synthesized either by mechanical mixing of
the two components or by covalently linking the nanotubes to the matrix. The
various procedures will be overviewed and the determining factors will be
identified for the best mechanical properties of the composites. On the other
hand, it will be shown that for highest electrical conductivity much smaller
amounts of carbon nanotubes are needed if the nanotubes can be aligned. The
thermal conductivity of the nanocomposites will also be overviewed. Finally,
together with nanoclay particles, nanotubes are inducing remarkable flame
retardant properties in the nanocomposites materials.