Gels synthetic

Sodium aluminate, 2 345t, 358-359 analysis, 2 275-276 economic aspects, 2 275 health and safety factors, 2 276 manufacture, 2 274-275 neutralization, 2 424 physical and chemical properties of, 2 273-274 uses of, 2 276-277 in water treatment, 26 111 Sodium aluminosilicate gels, synthetic zeolites prepared from, 16 831t Sodium aluminosilicates, 12 578 Sodium aluminum hydride, 13 621, 623-624... 

Proteins and nucleic acids are structure controlled monodispersed compounds that typically exhibit narrow bands as analytes on gels. Synthetic polymers, on... 

In the sol-gel synthetic method, the gel graduates from inert background material to product. The underlying chemistry remains the same. The silicon-dioxide network is often generated from tetraethyl orthosilicate (Si(OCH2CH3)4), commonly abbreviated TEOS. An alcoholic solution of TEOS undergoes hydrolysis and condensation when added to water to produce Si02( ) and ethanol ... 

Adsorption. Gaseous components (adsorbates) can be removed and recovered by selective adsorption/desorbtion by means of appropriate solid separation agents (adsorbents), as activated carbon, aluminium oxide, silica gel, synthetic zeolites (molecular sieves). Two types of adsorption may be distinguished Equilibrium Limited Adsorption, and Molecular Sieve Adsorption. 

The sol-gel synthetic technique is used to fabricate a porous structure composed of transition metal aUcoxides. These structures most commonly utilize a siloxane (Si O) to form the backbone structure. The synthesis of these sol-gels involves a hydrolysis of a silicone monomer followed by the condensation of the silica into a porous structure with a three-dimensional networked structure. The physical structures of these sol-gels can be tailored to produce structures with a wide range of useful properties and the chemical surface chemistry can be modified to produce various surface interactions. 

Gash AE, TiUotssynthetic route to transititm and main-group metal oxide aerogels using inorganic salt precursors. J Non Cryst Solids 285 22-28... 

The formation of organized nanostructures with amphiphiles can be used for the encapsulation of inorganic aggregates via processes that are inspired by classical sol-gel synthetic techniques. If linear structures are obtained, removal of the template by calcination or chemical etching generates inorganic nanowires. 

A large number of compoimds have been synthesized by following one or the other variant of sol-gel synthetic protocols, as described by Ganguli and Chatterjee (1997). It is our intention to describe here the most popular procedures and provide examples from the range of compounds synthesized by each of the procedures so as to present each option as a module, and describe some important properties of the products. Also to be described at the end of the Chapter are the procedures used for the fabrication of the so-called powderless ceramics/glass-ceramics mentioned above, and the degree of success achieved so far. 

Despite the fact that soft tissues are made of typical hydrogels, namely high-water content gels, synthetic hydrogels are used very little as biomateiials except for use in soft contact lenses. The reasons why synthetic hydrogels are not used in implantation have been explained here. Sjmthetic hydrogels nevertheless remain useful biomaterials, depending on the application. 

The polymerization of alloocimene [121] is reported in the patent literature I39-I41). Silica gel, synthetic silicates, and various Lewis acids were used as the catalysts. However, no details concerning the structure of the polymeric products were given. More recently, the cationic polymerization of alloocimene was investigated by Jones (71). An intra-intermolecular polymerization mechanism was postulated (11-57). The iodine number of the polymer indicated the loss of two double bonds per monomer unit during polymerization. Interestingly, the use of Ziegler-type catalysts did not yield cyclic polymeric structures (95, 96). 

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