Manufacture and Applications

The manufacture of C-fibers generally occurs by the thermal degradation of suitable organic polymers at temperatures between 900 to 3000°C (see Table 5.2-12). The weight loss accompanying the scission of ga.seous molecules (e.g. CH4, CO, N2) should be as low as possible. 

Carbon felt, carbon wool and woven carbon, which due to their isotropic structure only exhibit low mechanical strengths and low elasticity moduli, are manufactured by the pyrolysis of organic textiles. Depending on the form of the starting material utilized e.g. as woven textiles or felt, woven carbon or carbon felt is produced after carbonization. 

The manufacturing process proceeds in two stages, the first comprising the decomposition of the organic material at ca. 300°C (precoking). In the. second stage the precoked material is degraded at ca. lOOO C to elemental carbon in the absence of air. 

Carbon felts are mainly utilized for thermal insulation at high temperatures e.g. in resistive or induction furnaces. Carbon wool is manufactured by decomposing cotton wool or similar materials and is mainly utilized as a packing material for high temperature heat insulation. Its resistance to chemical corrosion makes it suitable as a filter material for corrosive media, as a support for catalysts and for corrosion-resistant linings in chemical plant. 

PAN-fibers are currently mainly utilized for the industrial manufacture of anisotropic reinforcing fibers of the HT- and HM-types. The production process is. shown in the flow chart below (Fig. 5.2-3). 

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Jeanette Scott, ed.. Hollow Fibers Manufacture and Applications, Chemical Technology Keview No. 194, Noyes Data Corp., Park Ridge, N.J., 1981. 

C. J. Boner, Manufacture and Application ofEubricating Greases, Reinhold Publishing Corp., New York, 1954. 

The COP s of specific air conditioners will vary widely with both manufacturer and application. Electricity utility efficiencies will also differ between countries. However, the reason for the economic interest in heat-driven cycles remains clear. Given that primary fuels can cost the consumer approximately 25% of the cost of electricity and that electricity frequently costs more at times of peak demand, there is justification for considering alternative systems. The use of a primary fuel at the point of use can also reduce COj and other emissions. 

V. M. L. Wood, Crystal science techniques in the manufacture of chiral compounds in Chirality and Industry II. Developments in the Manufacture and applications of optically active compounds, A. N. Collins, G. N. Sheldrake, J. Crosby (Eds.), John Wiley Sons, New York (1997) Chapter 7. 

The synthetic dye industry is well over 100 years old with manufacture and application of dyes being carried out globally. Environmentally, the... 

Although chlorophyll and chlorophyllin colorants seem to be easily obtained, in practice their production as natural food colorants is rather difficult. The sensitivity of chlorophylls to certain enzymes, heat, and low pH, and their low tinctorial strength greatly limit their manufacture and application as food additives, principally when the pigments are isolated from the protective environment of the chloroplasts. The well-known instability of chlorophylls prompted extensive research for developing... 

Green Chemistry is the utilization of a set of principles that reduces or eliminates the use or generation of hazardous substances in the design, manufacture and application of chemical processes. This non-regulatory approach for pollution prevention occupies a pivotal position in the management of hazardous substances and has been quite successful as evidenced, for example, in the United States by the Presidential Green Chemistry Challenge Awards. ... 

The vast capacity of SCS-based methods are related to simplicity of manufacturing and application of sensitive elements as well as with their unique response to adsorption of chemically active particles of different nature and structure. 

Rheology is the study of flow and deformation of materials under the influence of external forces. It involves the viscosity characteristics of powders, liquids, and semisolids. Rheological studies are also important in the industrial manufacture and applications of plastic materials, lubricating materials, coatings, inks, adhesives, and food products. Flow properties of pharmaceutical disperse systems can be of particular importance, especially for topical products. Such systems often exhibit rather complex rheological properties, and pharmaceutical scientists have conducted fundamental investigations in this area [58-64],... 

TCP), and pentachlorophenol (PCP), in order of abundance. Minor amounts of other trichlorophenols and dichlorophenols may also be present, as well as recalcitrant polychlorinated phenoxyphenols (PCPPs) and PCDD/Fs as impurities [75, 76]. In Finland, approximately 30,000 tons of CP products were used between 1934 and 1988, when they were banned because of their potential toxicity to humans and the environment [77, 78]. The careless manufacturing and application of wood preservatives together with the lack of suitable waste disposal caused massive contamination of river sediments and sawmill sites. For example, the river Kymijoki in southern Finland was identified as the largest source of dioxins accumulating in fish in the entire Baltic area. Similar products were used in other European countries, especially Nordic countries with a large forestry industry, such as Sweden [79]. 

Detailed accounts of fibers and carbon-carbon composites can be found in several recently published books [1-5]. Here, details of novel carbon fibers and their composites are reported. The manufacture and applications of adsorbent carbon fibers are discussed in Chapter 3. Active carbon fibers are an attractive adsorbent because their small diameters (typically 6-20 pm) offer a kinetic advantage over granular activated carbons whose dimensions are typically 1-5 mm. Moreover, active carbon fibers contain a large volume of mesopores and micropores. Current and emerging applications of active carbon fibers are discussed. The manufacture, structure and properties of high performance fibers are reviewed in Chapter 4, whereas the manufacture and properties of vapor grown fibers and their composites are reported in Chapter 5. Low density (porous) carbon fiber composites have novel properties that make them uniquely suited for certain applications. The properties and applications of novel low density composites developed at Oak Ridge National Laboratory are reported in Chapter 6. 

The main deficiency of existing schemes is that they focus on the exclusion of certain hazardous dyes but do not take into account that it is the conditions of manufacture and application that are the most important determinants of environmental impact [68,70]. 

Baillie, C.A., Castle, J.E., Watts, J.F. and Bader, M.G. (1991). Chemical aspects of interface adhesion between electrolytically oxidised carbon fibers and epoxy resins. In Proc. ICCMI8, Composites Design, Manufacture and Application. (S.W. Tsai and G.S. Springer, eds.), SAMPE Pub. Paper HE. 

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