Résumé
Polyurethane aerogels were prepared via sol-gel synthesis and dried with supercritical carbon dioxide (CO2) according to catalyst concentration. The influence of this parameter was investigated, first in order to modify the reaction kinetics, then to study its impact on several characteristics. It was observed that this parameter influences the global shrinkage and the bulk density of the resulting materials. The effect of catalyst concentration on the dry samples was then studied in terms of textural, thermal and mechanical properties, thanks to scanning electron microscopy (SEM), nitrogen (N2) adsorption, non-intrusive mercury (Hg) porosimetry, thermal conductivity measurements and uniaxial compression tests. Results allowed us to identify correlations between these characteristics and to determine an optimal density range for thermal and mechanical compromise associated with a fine internal mesoporous texture.