Filler Aerogels

The third family of research grade materials is less well defined and encompasses aerogels of carbon [81,82] designed mesoscopic void structures in C3 with nanostruc-tured fillers [51,83], composites with nanocarbon fillers [24,82,84 88] and carbon-heterostructure [54,89-94] compounds. The references stated here are only examples for a wide range of activities stemming from the efforts to synthesize novel nanostruc-tured composites. These materials often exhibit unusual surface properties and are used in electrochemical and catalytic applications rather in the domain of traditional C3 compounds where mechanical properties dominate the application profile. 

Very finely divided colloidal silica powders can also be obtained by treating certain silicate minerals such as clay or calcium silicate with acid, followed by suitable heat treatment in an alkaline medium. Similarly, finely divided colloidal silicas can be produced by precipitating silica from a solution of sodium silicate with carbon dioxide. Such precipitated silicas are commonly used as reinforcing fillers, for elastomers because they are extremely finely divided, and the ultimate particles are easily broken apart. Finely divided aerogels of silicas may be employed, such as those described by Kistler in U.S. Pat. Nos. 2,093,454 and 2,249,767. 

Silica fillers are generally used with silicone rubbers. These materials with particle sizes in the range 0.003-0.03 pm are prepared by combustion of silicon tetrachloride (fume silicas), by precipitation, or as an aerogel. 

Vacuum panels have been stndied as a means to improve thermal insolation for a long time. Several insnlating fillers, snch as silica and perlite powders [1, 2, 3], fibre glass [4, 5], and aerogels [6, 7, 8] have been proposed as core materials for VIP, each of them... 

Lee K (2007) Organic aerogels reinforced with inorganic fillers. US Patent 2007/0259979. 

Synthetic silica types are used in coatings less as filler than as thixotropic, antisettling and matting additives. The different types include pyrogenic silica, precipitated silica and silica aerogels and hydrogels. They consist of coagulated amorphous spherical particles of very fine... 

Selection of raw materials for adhesives is very important to reduce environmental loads. At first, the raw materials should be environment fnendly. Synthetic polymers have relatively larger energy consumption in this production process than other materials such as fillers, including alumina powders, silica aerogels, caldum carbonate or talc consisting of minerals. Therefore, the composition of an adhesive is influential to the total environmental loads. In addition, if an adhesive is burned in the disposal process of the product bonded with it, carbon dioxide is emitted. As seen above, the presence of fillers can help to reduce the carbon dioxide emission because the portion of polymer in the adhesive decreases. 

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