Carbon black fibers

Drubeski et al. [35] investigated the electrical properties of electrically conductive hybrid carbon fiber-carbon black fiber polypropylene composites. These properties were evaluated by resistance measurements and scanning electron microscopy, respectively. 

Choosing carbon black as a filler for fibers has many implications. Figure 19.18 shows the effect of carbon black loading on viscosity in PET. Viscosity depends on the type of carbon black. A reduction of 50% viscosity can be attained at the same carbon black concentration simply by change to another grade of carbon black. Moisture absorption, which affects the drying time, can be substantially reduced (by about 50%) by the selection of the appropriate carbon black. Fiber color and tone are affected by the carbon black type and by the method of its dispersion. 

Excellent insulating properties, along with the abiUty to be stmctural components, make plastics the ideal candidate materials for electrical appHcations. Although generally used as insulators, carbon black or carbon fiber can be added to make plastic materials electrically conductive, thereby expanding their usefulness in the electronics area. 

Antistats such as polyoxyethylenes (151,152) and A/-alkyl polycarbonamide (153) are added to nylon to reduce static charge and improve moisture transport and soil release in fabrics. These additives also alter the luster of fiber spun from bright polymer. Static reduction in carpets is achieved primarily by the use of fibers modified with conductive carbon black (see Antistatic agents Carbon, carbon black). 

Bicomponent technology has been used to introduce functional and novelty effects other than stretch to nylon fibers. For instance, antistatic yams are made by spinning a conductive carbon-black polymer dispersion as a core with a sheath of nylon (188) and as a side-by-side configuration (189). At 0.1—1.0% implants, these conductive filaments give durable static resistance to nylon carpets without interfering with dye coloration. Conductive materials such as carbon black or metals as a sheath around a core of nylon interfere with color, especially light shades. 

Rubber. The mbber industry consumes finely ground metallic selenium and Selenac (selenium diethyl dithiocarbamate, R. T. Vanderbilt). Both are used with natural mbber and styrene—butadiene mbber (SBR) to increase the rate of vulcanization and improve the aging and mechanical properties of sulfudess and low sulfur stocks. Selenac is also used as an accelerator in butyl mbber and as an activator for other types of accelerators, eg, thiazoles (see Rubber chemicals). Selenium compounds are useflil as antioxidants (qv), uv stabilizers, (qv), bonding agents, carbon black activators, and polymerization additives. Selenac improves the adhesion of polyester fibers to mbber. 

Until the end of World War II, coal tar was the main source of these aromatic chemicals. However, the enormously increased demands by the rapidly expanding plastics and synthetic-fiber industries have greatly outstripped the potential supply from coal carbonization. This situation was exacerbated by the cessation of the manufacture in Europe of town gas from coal in the eady 1970s, a process carried out preponderantly in the continuous vertical retorts (CVRs), which has led to production from petroleum. Over 90% of the world production of aromatic chemicals in the 1990s is derived from the petrochemical industry, whereas coal tar is chiefly a source of anticorrosion coatings, wood preservatives, feedstocks for carbon-black manufacture, and binders for road surfacings and electrodes. 

Substitution of some of the alkoxy groups on the polytitanoxanes with glycols, P-diketones or P-ketoesters, fatty acids, diester phosphates or pyrophosphates, and sulfonic acids gives a group of products that are very effective surface-treating agents for carbon black, graphite, or fibers (32). 

Additives are used extensively in compounding this resin. Antioxidants (qv), uv stabilizers, especially carbon black (qv), and fillers (qv) such as glass fibers, sihca, or clay provide properties desirable for various purposes. 

A polymer blend is a physical or mechanical blend (alloy) of two or more homopolymers or copolymers. Although a polymer blend is not a copolymer according to the above definition, it is mentioned here because of its commercial importance and the frequency with which blends are compared with chemically bonded copolymers. Another technologically significant material relative to the copolymer is the composite, a physical or mechanical combination of a polymer with some unlike material, eg, reinforcing materials such as carbon black, graphite fiber, and glass (see Composite materials). 

Adsorption. Many studies have been made of the adsorption of soaps and synthetic surfactants on fibers in an attempt to relate detergency behavior to adsorption effects. Relatively fewer studies have been made of the adsorption of surfactants by soils (57). Plots of the adsorption of sodium soaps by a series of carbon blacks and charcoals show that the fatty acid and the alkaU are adsorbed independently, within limits, although the presence of excess aLkaU reduces the sorption of total fatty acids (58). No straightforward relationship was noted between detergency and adsorption. 

As far as conducting fillers are concerned, we have rather a wide range of choice. In addition to the traditional and long used fillers, such as carbon black and metal powders [13] fiber and flaky fillers on organic or metal bases, conducting textures, etc recently appeared and came into use. The shape of the filler particles varies widely, but only the particle aspect ratio, the main parameter which determines the probability... 

The properties of traditional fillers, such as carbon black, graphite, metal powders, carbon fibers, are described in detail in [13], therefore, new kinds of conducting fillers which have recently appeared will be considered below. 

This changing of the path of crack propagation gives the material the better resistant characters for fracture. The same type of phenomenon occurs in the materials filled with fibers. Fibers play the same role more clearly on reinforcing the materials and make the tensile strength much higher. Thus, surely we can expect that the strand of molecules and the super-networks work in the same manner in the carbon black-hlled mbber, which will be discussed in detail later. 

As discussed in Chapter 10, a wide variety of additives is used in the polymer industry. Stabilizers, waxes, and processing aids reduce degradation of the polymer during processing and use. Dyes and pigments provide the many hues that we observe in synthetic fabrics and molded articles, such as household containers and toys. Functional additives, such as glass fibers, carbon black, and metakaolins can improve dimensional stability, modulus, conductivity, or electrical resistivity of the polymer. Fillers can reduce the cost of the final part by replacing expensive resins with inexpensive materials such as wood flour and calcium carbonate. The additives chosen will depend on the properties desired. 

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