Fumed silica silicon dioxide

Silicic acid, disodium salt. See Sodium metasilicate Silicic acid hydrate Silicic acid hydrated. See Silica, hydrated Silicic acid, potassium salt. See Potassium silicate Silicic acid, sodium salt. See Sodium silicate Silicic anhydride Silicium dioxide. See Silica Silicon dioxide. See Novaculite Quartz Silica, fumed Silica Silicon dioxide, diatomaceous. See Diatomaceous earth Silicone... 

Aggregate, alumiiia (alumiiium oxide), cement raw mix, clay, dolomite, fluorspar, kaolin, light weight aggregate, lime, limestone, magnesia (magnesium oxide), pigments, silica (silicon dioxide), silica fume Products... 

Silicon Dioxide occurs in nature as agate, amethyst, chalcedony, flint, quartz, sand, and tridymite. Silicon dioxide is obtained by acid precipitation from a sodium silicate solution to yield veiy fine particles. If silicon dioxide is obtained by the addition of sodium silicate to a mineral acid, the product is termed a silica gel. The pharmaceutical industry uses colloidal silicon dioxide, which is a submicroscopic fumed silica prepared by the vapor phase hydrolysis of a silica compound, such as silicon tetrachloride. Other names for colloidal silicon dioxide include light anhydrous silicic acid, silicic anhydride, and silicon dioxide fumed. Colloidal Silicon Dioxide NF must meet the following standards ... 

On the other hand, the alkoxide system presented several problems in formulation. The system first chosen as a model consisted of a trimethoxymethyl silane crosslinker, 8000 centistoke HEB siloxane, and a catalyst. A number of catalysts were used and each exhibited different cure rates and electrical properties. DuPont tetraalkoxytitante-Tyzor appears to he one of the better catalysts used in this type of curing system. Fillers are usually incorporated into the silicone formulation to improve mechanical properties, promote adhesion, and to serve as light screening and pigment agents. Cab-o-sil, a form of fumed silica, carbon-black, titanium dioxide and calcium carbonate are then used as RTV fillers. 

Fumed Silica. Today colloidal silica (fumed silica) is the most common thixotropic agent in epoxy resins. Fumed silica, an amorphous silicon dioxide, is a versatile, efficient additive used for flow control and thixotropy. Fumed silica has long been the dominant thixotrope employed in the adhesive and sealant industry. 

Silicon Dioxide occurs as an amorphous substance that shows a noncrystalline pattern when examined by X-ray diffraction. It is produced synthetically, either by a vapor-phase hydrolysis process, yielding fumed silica, or by a wet process, yielding precipitated silica, silica gel, colloidal silica, or hydrous silica. Fumed silica is produced in an essentially anhydrous state, whereas the wet-process products are obtained as hydrates or contain surface-adsorbed water. 

Fumed silica occurs as a white, fluffy, nongritty powder of extremely fine particle size and is hygroscopic. The wet-process silicas occur as white, fluffy powders or as white, microcellular beads or granules and are hygroscopic or absorb moisture from the air in varying amounts. All of these forms of Silicon Dioxide are insoluble in water and in organic solvents, but they are soluble in hydrofluoric acid and in hot, concentrated solutions of alkalies. 

Fumed silica appears as a fluffy white powder characterized by an extremly low bulk density down to the range of about 20-50 g f. In contrast, the submicron fumed silica particle consists of amorphous silicon dioxide and, hence, its true density is about 2200 g 1 ... 

The chemistry of a finely divided solid with high surface area is at the borderline between molecular chemistry and physics of solid surfaces. The surface of a finely divided amorphous silica may be understood as a two-dimensional projection of the three-dimensionally linked silicon dioxide tetrahedra. By this the chemistry of the fumed silica surface is dominated by Si-O-Si units and, in particular, dangling surface Si-0 bonds, which will create silanol groups under the influence of humidity at ambient temperature. 

Due to its high surface area, surface chemistry and physics dominate the properties of fumed silica. The O—Si-O being 0.3 to 0.4 nm let estimate about only 20 silicon dioxide units spanning the diameter of a primary particle of amorphous silica. Fumed silica therefore has an extremely high surface to bulk ratio up to about 10 %. This is why even bulk methods of chemical analysis are suitable to follow chemical reactions on its surface elemental analysis, IR or NMR methods, etc. 

Fumed silica is a highly dispersed silicon dioxide of large industrial importance and a wide spectrum of applications. Due to its production in a flame process fumed silica exhibits a smooth and nonporous particle surface. Additionally to its high surface area fumed silica bears isolated and statistically distributed surface silanol groups that render this product hydrophilic. A most important technical reaction, therefore, is the silylation and hydrophobization of the hydrophilic surface. 

SYNS ACTICEL AEROSIL AMORPHOUS SILICA DUST AQUAFIL CAB-O-GRIP II CAB-O-SIL CAB-O-SPERSE CATALOID COLLOIDAL SIUCA COLLOIDAL SILICON DIOXIDE DAVISON SG-67 DICALITE DRI-DIE PESTICIDE 67 ENT 25,550 FOSSIL FLOUR FUMFX) SILICA FUMED SILICON DIOXIDE O LUDOX NALCOAG NYACOL NA ACOL 830 NYACOL 1430 SANTOCEL SG-67 SIUCA, AMORPHOUS SILICIC ANHYDRIDE SIUCON DIOXIDE (FCQ SIUKILL VULKASIL... 

Aerosil Cab-O-Sil Cab-O-Sil MSP-, colloidal silica fumed silica light anhydrous silicic acid silicic anhydride silicon dioxide fumed Wacker HDK. 

Colloidal silicon dioxide is a submicroscopic fumed silica with a particle size of about 15 nm. It is a light, loose, bluish-white-colored, odorless, tasteless, nongritty amorphous powder. 

CAB-O-SPERSE CATALOID COLLOIDAL SILICA COLLOIDAL SILICON DIOXIDE DICALITE DRI-DIE INSECTICIDE 67 FLO-GARD FOSSIL FLOUR FUMED SILICA FUMED SILICON DIOXIDE HI-SEL LO-VEL LUDOX NALCOAG ... 

In The Chemistry of Silica [1], Her used the term silica powders as a broad category encompassing silica gels, precipitated silicas, and fumed or pyrogenic silicas. These are all forms of synthetic amorphous silicon dioxide, a broad category that also includes another form — silica sols or coUoidal silica — that is not a powder, but rather a dispersion of discrete silica particles in a liquid medium. 

Colloidal silicon dioxide. See Silica, colloidal Silica, fumed... 

Fumaric acid, diallyl ester. See Diallyl fumarate Fumaric acid, dibutyl ester. See Dibutyl fumarate Fumaric resin. See Maleic resin Fumed silica Fumed silicon dioxide. See Silica, fumed Fural 2-Furaldehyde Furale. See Furfural... 

CAS 112945-52-5 EINECS/ELINCS 231-545-4 Synonyms Amorphous silica dust Cl 77711 Colloidal silica Colloidal silicon dioxide Eossil flour Eumed silica Fumed silicon dioxide Pigment white 27 Silica, amorphous Silica, amorphous fumed Silica, pyrogenic Silicic anhydride Silicon dioxide Definition High surface area aggregate particles of silica, with min. 89.5% SiOj content Empirical OjSi Formula SiOj... 

Silicon dioxide. See Quartz Silica, fumed Silica... 

Colloidal silicon dioxide. See Silica, colloidal Silica, fumed Colloidal sulfur Synonyms Sulfur, colloidal Definition Pale yel. dried mixt. of sulfur and acacia Uses Antimicrobial in cosmetics Manuf./Distrib. Aldrich http //www.sigma-aldrich.com, Allan http //www.allanchem.com]... 

Fumed silica Fumed silicon dioxide Pigment white 27 Silica, amorphous Silica, amorphous fumed... 

It was postulated that the silicon dioxide molecule is a first intermediate product in the route from silicon tetrachloride to fumed silica. Due to high temperatures in the flame the ortho-silicon acid or meta-silicon acid will not be the main product of silicon tetrachloride hydrolysis or/and oxidation. The silicon dioxide molecule is well known to be stable at high temperatures or in a matrix-isolated state. Therefore, we are able to use silicon dioxide molecules as initial silicon-containing substances to simulate silica particle formation. Meta-silicon acids are able to react with other meta-silicon acid molecules and produce bigger clusters. Three meta-silicon acid molecules form cyclic clusters with four-coordinated silicon atoms and two-coordinated oxygens (Fig. 1). At high temperatures this cluster may loose some water molecules from hydroxyl groups and... 

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