Formation of glass-like materials from ethyl silicate

Porous Materials

“…Since water is a component of the reaction system, it is bound to affect the porosity of the gels through not only hydrolysis but also because of its high surface tension during drying. Several researchers have investigated the role of water in controlling the gel structure [52][53][54][55][56][57][58][59]. Yoldas [52] has demonstrated that the mole ratio of water to alkoxide clearly affects the oxide content as can be seen from Figure 4.25 and this, in turn, clearly affected the shrinkage characteristics apparently because of different porosities.…”

“…They found that the density of the initial microporous dried film increased with increasing H20/TEOS ratio. Jones et al [56] showed that clear, transparent, glass-like gels can be prepared when the water content in the system exceeded 16%. Below 16% water, the silica system showed good fiber forming ability.…”

“…18, 33, 45, 48, 50, 54--5, 57, 60, 183, 184, 189, 194, 195, 198, 199, 221 ,) 16, 18,22, 33, 34 ceramics 1,5,10,12,14,16,17,31,33, 38,43--4,48,49,50,52,54,55,56, 61, 181, 182, 183, 184, 189, 191, 194, 198, 199 1,5,6,10,12,14,16,17,18,28,38,43,44,50,52,55,56,181,182,183,186,189,194,195,197,198,199 190,191,193,194,198,199, 38,57,184,190,194,197,198,210 188,194,198,199 …”

Magnesia Synthesis via Sol−Gel: Structure and Reactivity

“…When the gels are thermally treated, the magnesium hydroxide (brucite) is dehydroxylated until magnesium oxide is obtained. In previous work it has been shown that pH and water concentrations can be used to control hydrolysis and polymerization. , …”

Propiedades catalíticas de óxido de magnesio y de metales soportados en óxido de magnesio

“…Por tal razón, cabe esperar que el pH de la mezcla reaccionante determine cierto grado de hidroxilación en los geles precursores del MgO y que el tratamiento térmico deshidroxile a la brocita hasta obtener el óxido de magnesio. Un estudio previo sobre la preparación de estos materiales mostró que el pH y la cantidad de agua pueden ser usados para controlar las reacciones de hidrólisis y de polimerización [69,70].…”