Year: 2015
Type: review
Abstract: Sets of silica gels: aerogels, xerogels and sintered aerogels, have been studied in the objective to understand the mechanical behavior of these highly porous solids. The mechanical behaviour of gels is described in terms of elastic and brittle materials, like glasses or ceramics. The magnitude of the elastic and rupture modulus is several orders of magnitude lower compared to dense glass. The mechanical behaviours (elastic and brittle) are related to the same kinds of gel characteristics: pore volume, silanol content and pore size. Elastic modulus depends strongly on the volume fraction of pores and on the condensation reaction between silanols. Concerning the brittleness features: rupture modulus and toughness, it is shown that pores size plays an important role. Pores can be considered as flaws in the terms of fracture mechanics and the flaw size is related to the pore size. Weibull's theory is used to show the statistical nature of flaw. Moreover, stress corrosion behaviour is studied as a function of environmental conditions (water and alcoholic atmosphere) and temperature.
Source: Gels
DOI: 10.3390/gels1020256
Institutions: Centre National de la Recherche Scientifique, Aix-Marseille Université, Institut Méditerranéen de Biodiversité et d'Ecologie Marine et Continentale, Institut de Recherche pour le Développement, Universidad del Zulia, Escuela Superior Politecnica del Litoral, Hospital Universitario de Maracaibo, Laboratoire Charles Coulomb, Université Montpellier 2
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,534
OpenAlex ID: W2192943331