Granular aerogels

Figure 7 Directional-hemispherical solar transmission tdh as a function of density p for different aerogels granular aerogel (diamond) low-density aerogel tiles from LLNL (L. W. Hrubesh, squares) aerogel tiles from DESY, Hamburg (G. Poelz, filled circles) specimens made by P. Wang (University of Wiirzburg) at pH 13 (open circles) and pH 11 (asterisks). Thickness of all specimens was 20 mm.

Azevedo, M.N., N. Xiang and C. Fackler. 2011. Low frequency absorption and attenuation of granular aerogel composites. 40th International Congress and exposition on noise control engineering 2011, INTER-NOISE 2011, INCEJ and ASJ, September 4-7, in Osaka, Japan. 

Figure 45.8 Cross-section of the granular aerogel-based glazing, consisting of two glass panels with a low-emissivity coating on the inside, two gaps, and an aerogel-filled PMMA double-skin sheet [25].

Silica-gel ndsotbents are composed of a rigid three-dimensional network of spherical particles of amorphous colloidal silica (Si02). They were reparted as early as 1640 and commercial production was begun around 1919. The surface area is generated by the very flue size of the colloidal panicles. They exhibit surface areas from as little as 100 m2/g for the "aerogels" to over 800 m2/g, The product is provided both in granular and spherical forms. 

One of the most promising options of flexible insulation materials to be used for translucent foil structures involves granular silica aerogel as insulation material - see Fig. 12.2 (Cremers, 2008). Not only does aerogel have excellent thermal-insulation properties (see r-values and /-values in Fig. 12.3), but it is translucent as well. 

Granular Silica Aerogel (Nanogel ) by Cabot Corp. 

Broecker FJ, Heckmann W, Fischer F, Mielke M, Schroeder J, Stange A (1986) Stmctural analysis of granular silica aerogel. Springer Proc Phys 6 160-166... 

Broecker F J, Heckmann W, Fischer F et al (1985) Structural Analysis of Granular Silica Aerogels. In Fricke J (ed) International Symposium on Aerogels 6, Springer, Heidelberg... 

Figure 26.11. Influence of the system pressure (vacuum quality) on the effective thermal conductivity of granular and monolithic silica aerogel (as measured by the hot-wire technique under ambient conditions) [28].

Polymeric aerogels were developed as binders for foundry sands in the last decade to solve certain problems, which are typical for classical organic binders. In the last few years, organic and inorganic aerogels were developed in granular form as additive to foundry sands to improve certain properties such as metal penetration, fineness, and collapsibility. 

Abstract Cabot Corporation manufactures a hydrophobic aerogel in granular form sold worldwide. This contribution outlines the history of the company, the basic Cabot process, and several but not exhaustive applications in the field of architectural daylighting, building insulation, oil and gas pipelines, LNG and cryogenic applications, outdoor gear and apparel, coatings and specialty chemicals, and personal care. Four different products are described and their properties are discussed. 

Nano-additives Aerogels are a nano-stmctured granular additive to foundry sand improving mould and core properties... 

Forest, L., V. Gibiat, and A. Hooley. 2001. Impedance matching and acoustic absorption in granular layers of silica aerogels. Journal of Non-Crystalline Solids 285(1-3) 230-235. 

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