Abstract: A method of preparing a metal oxide which is dispersible in organic matrices such as apolar organic liquid wherein a product mixture is formed by adding sol of the metal oxide to an aqueous suspension of a sulfonic acid modifier, the modified metal oxide being recovered from the product mixture.
Type:
Application
Filed:
April 21, 2005
Publication date:
June 19, 2008
Inventors:
Thomas J. Martin, April J. Arthur, C.Todd Hancock, Victoria L. Stolarski
Abstract: Glassy articles are prepared by subjecting to hydrolysis and policondensation a solution or suspension of a suitable precursor, mainly comprising a silicon alkoxide, and by drying the obtained gel in a pressure chamber, the gel solvent having been substituted by a non-protic solvent, mainly acetone, under nitrogen flowing, at temperature and pressure conditions lower than the gel solvent critical values. The dried gel is then densified by a thermal treatment.
Type:
Grant
Filed:
December 23, 2003
Date of Patent:
February 27, 2007
Assignee:
Degussa Novara Technology, S.p.A.
Inventors:
Giulio Boara, Massimo Sparpaglione, Lorenzo Costa
Abstract: Pyrogenically prepared silicon dioxide with the following physicochemical properties: 1. Average particle size (D50 value) D50?150 nm (dynamic light scattering, 30 wt %) 2. Viscosity (5 rpm, 30 wt %) ??100 m·Pas 3. Thixotropy of Ti (?(5 rpm))/(?(50 rpm))?2 4. BET surface area 30-60 m2/g 5. Compacted bulk=100-160 g/L 6. Original pH?4.5 that can be used for the preparation of dispersions and glass bodies.
Type:
Grant
Filed:
December 8, 2003
Date of Patent:
May 10, 2005
Assignee:
Degussa AG
Inventors:
Monika Oswald, Gerrit Schneider, Klaus Deller
Abstract: Disclosed is a method for fabricating high-purity silica glass using a sol-gel processing that includes the steps of: (a) mixing a deionized water with a fluorine compound and a dispersion agent to prepare an aqueous premix solution; (b) mixing the aqueous premix solution with a fumed silica; (c) mixing the resulting mixture to form a dispersed sol; (d) aging the sol at the ambient temperature to stabilize silica particles; and, (e) removing air voids from the sol and adding a gelation agent.
Abstract: A dispersion comprising fine porous inorganic oxide particles, e.g., silica gel particles, wherein the particles have a median particle size below three microns. The dispersed particles have a porosity after drying in which at least about 0.50 cc/g of pore volume is from pores having a pore size of 600 Å or less as determined by nitrogen porosimetry. Embodiments prepared from silica gel have porosity after drying in which at least about 0.7 cc/g of pore volume is from pores having a diameter of 600 Å or smaller. The particles of the dispersion also can be described as having viscosity derived pore volume of at least about 0.5 g/cc. The dispersion is prepared by forming a dispersion from inorganic oxides having sufficient rigid structure to maintain porosity after milling and drying. After the inorganic oxide is selected, it is milled to have a median particle size of 0.05 to about 3 microns.
Abstract: The present invention relates to a process for the preparation of organically modified aerogels, comprising
a) the preparation of a silicic acid sol having a pH of ≦4.0 from an aqueous water glass solution, with the aid of at least one organic and/or inorganic acid;
b) polycondensation of the resulting silicic acid sol to a SiO2 gel by the addition of a base;
c) washing the gel obtained in Step b) with an organic solvent until the water content of the gel is ≦5% by weight;
d) surface-silylating the gel obtained in Step c), and
e) drying the surface-silylated gel obtained in Step d), characterized in that at least one acid forms difficultly soluble salts with the cations of the water glass in the silicic acid sol, and that before Step b) the resulting difficultly soluble salts are extensively precipitated and separated from the silicic acid sol.
Abstract: Sticky high water content gelled fire extinguisher compositions hold the antage of providing a high water content, slightly viscous (sticky) gel with flow properties similar to water. The ability of this material to stick to burning surfaces is what sets it apart from water extinguishers. Not only are fires extinguished, but also surfaces are cooled by the sticky gel as the water evaporates. The basic gelled fire extinguisher composition is comprised of about 88 weight percent water and about 12 weight percent of a 7 nanometer particle size silicon dioxide gellant. The silicon dioxide gellant is available as EH5 tradename by Cabot for this silicon dioxide gellant. Other ingredients such as dispersants, wetting agents and flame retardants can be used as additives in combination with the gelling agent. The actual gel system is inexpensive, made from readily available ingredients and easily prepared.
Type:
Grant
Filed:
March 16, 1998
Date of Patent:
December 14, 1999
Assignee:
The United States of America as represented by the Secretary of the Army
Inventors:
William D. Stephens, Leo K. Asaoka, Christi L. Salter