Fiber material, plastic

For most hydrardic pressure-driven processes (eg, reverse osmosis), dense membranes in hoUow-fiber configuration can be employed only if the internal diameters of the fibers are kept within the order of magnitude of the fiber-wall thickness. The asymmetric hoUow fiber has to have a high elastic modulus to prevent catastrophic coUapse of the filament. The yield-stress CJy of the fiber material, operating under hydrardic pressure, can be related to the fiber coUapse pressure to yield a more reaUstic estimate of plastic coUapse ... 

The mixed monocyclic aromatics are called BTX as an abbreviation for ben2ene, toluene, and xylene (see Btxprocessing). The benzene and toluene are isolated by distillation, and the isomers of the xylene are separated by superfractionation, fractional crystallisation, or adsorption (see Xylenes and ethylbenzene). Bensene is the starting material for styrene (qv), phenol (qv), and a number of fibers and plastics. Toluene (qv) is used to make a number of... 

Ammonia is used in the fibers and plastic industry as the source of nitrogen for the production of caprolactam, the monomer for nylon 6. Oxidation of propylene with ammonia gives acrylonitrile (qv), used for the manufacture of acryHc fibers, resins, and elastomers. Hexamethylenetetramine (HMTA), produced from ammonia and formaldehyde, is used in the manufacture of phenoHc thermosetting resins (see Phenolic resins). Toluene 2,4-cHisocyanate (TDI), employed in the production of polyurethane foam, indirectly consumes ammonia because nitric acid is a raw material in the TDI manufacturing process (see Amines Isocyanates). Urea, which is produced from ammonia, is used in the manufacture of urea—formaldehyde synthetic resins (see Amino resins). Melamine is produced by polymerization of dicyanodiamine and high pressure, high temperature pyrolysis of urea, both in the presence of ammonia (see Cyanamides). 

A rather impressive Hst of materials and products are made from renewable resources. For example, per capita consumption of wood is twice that of all metals combined. The ceUulosic fibers, rayon and cellulose acetate, are among the oldest and stiU relatively popular textile fibers and plastics. Soy and other oilseeds, including the cereals, are refined into important commodities such as starch, protein, oil, and their derivatives. The naval stores, turpentine, pine oil, and resin, are stiU important although their sources are changing from the traditional gum and pine stumps to tall oil recovered from pulping. 

Thermosetting unsaturated polyester resins constitute the most common fiber-reinforced composite matrix today. According to the Committee on Resin Statistics of the Society of Plastics Industry (SPl), 454,000 t of unsaturated polyester were used in fiber-reinforced plastics in 1990. These materials are popular because of thek low price, ease of use, and excellent mechanical and chemical resistance properties. Over 227 t of phenoHc resins were used in fiber-reinforced plastics in 1990 (1 3). PhenoHc resins (qv) are used when thek inherent flame retardance, high temperature resistance, or low cost overcome the problems of processing difficulties and lower mechanical properties. 

FIG. 10-184 Cost of shop-fabricated tanks in mid-1980 with V4-in walls. Multiplying factors on carbon steel costs for other materials are carbon steel, 1.0 mbber-lined carbon steel, 1.5 alnminnm, 1.6 glass-lined carbon steel, 4.5 and fiber-reinforced plastic, 0.75 to 1.5. Multiplying factors on type 316 stainless-steel costs for other materials are 316 stainless steel, 1.0 Monel, 2.0 Inconel, 2.0 nickel, 2.0 titanium, 3.2 and Hastelloy C, 3.8. Multiplying factors for wall thicknesses different from V4 in are ... 

Mechanical Hygrometers Materials such as human hair, wood fiber, and plastics have been used to measure humidity. These methods rely on a change in dimension with humidity. 

J. F. Mandell, Experimental Investigation of the Buckling of Anisotropic Fiber Reinforced Plastic Plates, Air Force Materials Laboratory Technical Report AFML-TR-68-281, October 1968. 

The choice of manufacturing technology for the fabrication of fiber-reinforced plastics or composite materials is intimately related to the performance, economics, and application of the materials. It also depends upon a number of factors, such as component numbers required, item complexity, number of molded surfaces, and type of reinforcement. 

Fiber-reinforced plastics have been widely accepted as materials for structural and nonstructural applications in recent years. The main reasons for interest in FRPs for structural applications are their high specific modulus and strength of the reinforcing fibers. Glass, carbon, Kevlar, and boron fibers are commonly used for reinforcement. However, these are very expensive and, therefore, their use is limited to aerospace applications. 

Fiber-reinforced plastics differ from many other materials because they combine two essentially different materials of fibers and a plastic into a single composite. In this way they are somewhat analogous to reinforced concrete, that combines concrete and steel. However, in the RPs the fibers are generally much more evenly distributed throughout the... 

Thus, it is necessary to allow for the fact that two widely dissimilar materials have been combined into a single unit. In the basic design approach certain fundamental assumptions are made. The first, and most important assumption, is that the two materials act together. With a load applied (stretching, compression, twisting, etc.) the fibers and plastic under load is the same that is, the... 

Fiber reinforced ceramics such as C/SiC, SiC/SiC can be manufactured by the polymer infiltration and pyrolysis technique at reasonable cost. The developed production technique allows the manufacturing of large and complex structures comparable to fiber-reinforced plastics. The material has excellent high temperature resistance, low density, and good damage tolerance, and is therefore well... 

The temperature of the inlet waste gas flow is generally restricted by the choice of materials. Plastic fiber beds are generally restricted to operate below 60°C (140°F). 

Singer, L.S. (1989). Carbon fiber reinforced plastics. In Concise Encyclopedia of Composite Materials (A. Kelly, ed ), Perganion Press. Oxford, pp. 39-55. 

All this is true both for low molecular weight compounds and for polymers. However, relevant differences are found not only in specific structural features, but also in the different intent with which the analysis is carried out. In common otganic stereochemistry, attention is essentially on reactivity Many aspects of regio- or stereoselectivity, as weU as reaction rate, can be explained or predicted in terms of conformation. In contrast, in polymers, the focus of interest is almost always on the physical (or mechanical) properties. It should not be forgotten that polymers are principally used as materials (plastics, fibers, elastomers, etc.) and that their properties are sometimes modified during fabrication. The fabri-cation process may induce the formation of particular structures at the molecular and supetmolecular level, which can often be traced back to conformational factors. 

---