Highly porous aerogels of very low permeability

• Autorzy: Phalippou J. , Woignier T. , Sempéré R. , Dieudonné P.
• Konferencja: International Conference on Sol-Gel materials SGM 2001, Rokosowo, Poland
• Języki publikacji: EN

Abstrakty

EN

In this paper, we firstly investigate the way the pores are created in silica gel during gelation. Then we show that the solid particle arrangement acts on the geometrical pore characteristics (pore volume and pore size distribution). According to the pore size value, the permeability of gels is quite low even if the value of the gel porosity exceeds 95%. Analogous properties can be extended to silica aerogels for which now the solvent is replaced by air. Consequently, and according to their low permeability, light weight aerogels exhibit very striking response to mechanical stresses. Here we report unusual experiments allowing us to estimate the mechanical properties of aerogels thanks to their low value of the average pore size. Moreover, one demonstrates that aerogels may be densified at room temperature using an external isostatic pressure. In that case, the pore size may be tailored with respect to the nature and the characteristics of the starting aerogel. The evolution of the textural properties such as the mean pore size and the specific surface area of these tailored aerogels is investigated as a function of isostatic pressure.

Słowa kluczowe

EN

silica gel; mechanical properties; aerogels

• Wydawca: Oficyna Wydawnicza Politechniki Wrocławskiej
• Czasopismo: Materials Science
• Rocznik: 2002
• Tom: Vol. 20, No. 1
• Strony: 29--42
• Opis fizyczny: Bibliogr. 34 poz.,

Twórcy

autor

Phalippou J.

autor

Woignier T.

autor

Sempéré R.

autor

Dieudonné P.

• Laboratoire des Verres - UMR CNRS 5587, Université de Montpellier 2, Place Eugčne Bataillon, 34095 Montpellier Cedex 5, France