Amorphous Materials, Industrial

In addition several other materials have been reported by industrial companies, but have not at the time of writing been commercialised. These include the product of condensation of 2,2-bis-(p-aminocyclohexyl)propane (VI) (Figure 18.28) with a mixture of adipic and azelaic acid (Phillips Petroleum), a research material produced in the old German Democratic Republic obtained by melt condensation of /ranj -cyclohexane-l,4-dicarboxylic acid (VII) (Figure 18.28) and the two trimethylhexamethylenediamine isomers used in the manufacture of Trogamid T, and another amorphous material (Rilsan N by Ato Chimie). 

L2. Lewis, W. K., Squires, L., and Broughton, G., Industrial Chemistry of Colloidal and Amorphous Materials. Macmillan, New York, 1942. 

There are also colloidal "sols in which dispersed and dispersion mediums are solids (Eg alloys, plastics, glass, some minerals, etc) Refs 1)J. Alexander, "Colloid Chemistry, Theoretical and Applied , 6 volumes, Van Nostrand, NY (1926-1946) 2)W.K.Lewis, L.Squires G.Broughton, "Industrial Chemistry of Colloidal and Amorphous Materials , Macmillan, NY (1943) 3)H.B.Weiser, "Colloid Chemistry , A Textbook, Wiley, NY (1949) 4)A.E. Alexander St P.John-... 

This serves as an example of the extremes one can go if one tmly wants to better understand the process and the form of the compound in the product. This approach is less important for detecting polymorphic form conversion in the solid state, since polymorphic solubility typically varies by less than a factor of two and tablets at very low strength would generally be classified as a type one by the biopharmaceutical classification system. In addition, polymorphs rarely have pronounced differences in chemical stability. On the other hand, if a compound is somewhat unstable and significant amount of amorphous material is potentially present, this approach can be used to determine if it is responsible for drug instability in the tablet formulation. In any event, this reference serves as a very good example of the strength of a powerful approach that has not been widely applied in our industry. 

G.Broughton, "Industrial Chemistry of Colloidal and Amorphous Materials , Macmillan, NY (1943) 3)H.B.Weiset, "Colloid Chemistry , A Textbook, Wiley, NY (1949) 4)A,E.Alexander P.John-... 

Lewis, Squires, and Broughton, Industrial Chemistry of Colloidal and Amorphous Materials, ... 

Discovery of amorphous silicon and its dopability has already had a tremendous impact on industrial applications of amorphous materials. Amorphous Si is now used fairly extensively as a photovoltaic material. In photovoltaic applications, solar photons excite the electrons across the gap and the resulting electron-hole pairs, are driven towards the respective electrodes in order to prevent their recombination. Electron is driven through an external resistance to generate the electrical power. The efficiency of conversion of solar energy to electrical power is characterized by an efficiency factor, r, which is given by. 

Cans, at the turn of the 19lh century, synthesised aluminosilicate materials capable of water softening. He called them Permutits and for many years they were employed as domestic and industrial water softeners, as well as in the treatment of nuclear waste. This, together with the first identification of base exchange in soils (Way [2] and Thompson [3 J), led to the misunderstandings perpetuated in elementary texts that zeolites are responsible for the ion-exchange in soils, and that they are widely used as water softeners. In truth the clay minerals contribute mainly to the ability of soils to take up cations, such as ammonium, and Permutits were amorphous materials with low cation exchange capacities and limited chemical stability. 

In addition to some one hundred papers in broadly diverse areas of chemical engineering, he was coauthor of Industrial Stoichiometry in 1926 and Industrial Chemistry of Colloidal and Amorphous Materials in... 

Organic zeolite analogues are commonly referred to as porous solids. These materials promise a new range of applications, e.g., in pharmaceutical manufacture and in molecular sieves, sensors, and devices. They are crystalline or amorphous materials that permit the reversible passage of molecules through holes on their surface. Porous solids are classified according to pore diameter nanoporous or microporous (< 15 A), mesoporous (15—500 A) and macroporous (>500 A). The natural and synthetic inorganic zeolites with uniform pore sizes of 10-20 A are the classical examples of microporous materials with widespread use in industry. 

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