𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Sol–Gel Synthesis of Microporous Amorphous Silica from Purely Inorganic Precursors

✍ Scribed by Maria-José Muñoz-Aguado; Miguel Gregorkiewitz

Publisher
Elsevier Science
Year
1997
Tongue
English
Weight
146 KB
Volume
185
Category
Article
ISSN
0021-9797

No coin nor oath required. For personal study only.

✦ Synopsis

Aqueous sodium silicate solutions and hydrochloric acid were used to prepare silica gels without any additives. In order to establish the optimum conditions for the preparation of microporous and monodisperse gels, the sol-gel reaction has been studied as a function of pH, concentration of silicate, time, and temperature. From 29Si NMR spectroscopy it was found that polycondensation sets on immediately after mixing the reagents, with a continuous increase of the fraction of 4-connected silicate tetrahedra (Q4) at the expense of Q1 and Q2. Polycondensation continues beyond the gelation point for 1 7, the order increases rapidly with pH. Gels formed at pH > 7 had an electrostatic nature and redissolved in water, whereas for pH

📜 SIMILAR VOLUMES

Sol–Gel Synthesis and Characterization o
Sol–Gel Synthesis and Characterization of Microporous Silica Membranes: II. Tailor-Making Porosity
✍ Wilma J. Elferink; Balagopal N. Nair; Renate M. de Vos; Klaas Keizer; Henk Verwe 📂 Article 📅 1996 🏛 Elsevier Science 🌐 English ⚖ 163 KB

It has been reported in the literature that the composition Unsupported silica membranes were prepared by acid-catalyzed of the synthesis solution influences the structure of the spehydrolysis and condensation of tetraethylorthosilicate. The possicies in the sol (3) and, hence, the final structure o

ChemInform Abstract: Sol—Gel Synthesis o
ChemInform Abstract: Sol—Gel Synthesis of Amorphous Calcium Phosphate and Sintering into Microporous Hydroxyapatite Bioceramics.
✍ P. LAYROLLE; A. ITO; T. TATEISHI 📂 Article 📅 2010 🏛 John Wiley and Sons ⚖ 36 KB 👁 2 views

Sol-Gel Synthesis of Amorphous Calcium Phosphate and Sintering into Microporous Hydroxyapatite Bioceramics. -An amorphous, nanosized, and carbonate-containing Ca phosphate powder (Ca:P ratio of 1.67) is synthesized from Ca(OEt) 2 and H 3 PO 4 in ethanol via sol-gel process. The powder is pressed at

Synthesis and characterization of nanoco
Synthesis and characterization of nanocomposite of polyimide–silica hybrid from nonaqueous sol–gel process
✍ Ging-Ho Hsiue; Jem-Kun Chen; Ying-Ling Liu 📂 Article 📅 2000 🏛 John Wiley and Sons 🌐 English ⚖ 433 KB 👁 2 views

Polyimide-silica (PI-SiO 2 ) hybrids with a nanostructure was obtained using the nonaqueous sol-gel process by polycondensation of phenyltriethoxysilane in a polyamic acid solution. Self-catalyzed hydrolysis of phenyl-substituted akoxysilane and modification on the polyimide structure are applied an