bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fibers, Olefin
Authors: Wust, Jr. C. J. 
Published: August 2004

Abstract
Olefin fibers, also known as polyolefin fibers, are synthetic fibers of growing commercial importance. Several olefin polymers are capable of forming fibers, but only polypropylene and polyethylene are of practical importance. From the first commercial application of polyethylene in automobile seat covers to multicomponent extrusion for specialty applications, olefin fibers have made a significant impact in the fiber industry. This article reviews the fiber properties, including physical, tensile, chemical, and thermal and ultraviolet stability, which make them ideally suited for these varied applications. Commercial fiber manufacturing and processing is discussed for staple fiber, continuous filament, and directly formed nonwovens. The extrusion, quench, and draw play integral roles in the development of the fiber properties. Bicomponent, high strength, and hard‐elastic fiber technology is examined.
Chloroethanes
Authors: Snedecor Gayle 
Published: August 2004

AbstractThe physical and chemical properties, manufacturing methods, uses, environmental concerns, and toxicity of the following chloroethanes are discussed: 1,1‐dichloroethane, 1,2‐dichloroethane, 1,1,1‐ trichloroethane, 1,1,2‐trichloroethane, 1,1,1,2‐tetrachloroethane, 1,1,2,2‐tetrachloroethane, pentachloroethane, and hexachloroethane.
Flame Retardants, Overview
Authors: Gann Richard G. 
Published: August 2004

AbstractFires result from an ignition source meeting a flammable product. Fire or flame retardants are commonly added to polymeric products to slow or prevent ignition and to reduce the intensity of burning should ignition occur. This article provides an introduction to fire retardants. It presents reasons why fire retardants are useful, general mechanisms for their effectiveness, how the performance of polymer‐retardant composites is measured, a summary of the market for these chemicals, and forces that might change that market.
Phosgene
Authors: Dunlap Kenneth L. 
Published: August 2004

AbstractPhosgene is a colorless, low boiling liquid which is manufactured by reaction of carbon monoxide and chlorine over activated carbon. It is a very toxic substance, and extensive safety procedures and equipment have been developed to help ensure the safe handling of phosgene. Phosgene is an important and widely used intermediate for chemical synthesis. Its primary use is for the manufacture of polyisocyanates for the polyurethane industry. Other uses are the production of polycarbonate, chloroformates, agrochemicals, and intermediates for pharmaceuticals and dyestuffs. Vol. 18, pp. 645–655, 91 refs. to August 1995.
Flame Retardants, Phosphorus
Authors: Weil Edward D. 
Published: August 2004

AbstractOne of the principal classes of flame retardants for plastics and textiles is that of phosphorus, phosphorus‐nitrogen, and phosphorus‐halogen compounds. These flame retardants are also used for wood and paper. The mechanisms of action, which may be in the condensed or vapor phase or in both, are presented. The interactions with other flame retardants are discussed.Commercial phosphorus‐based flame retardants include some inorganic compounds as well as both additive and reactive organic phosphorus systems. These materials range from simple salts to oligomeric compounds and encompass both liquids and solids. Some commercial products are pure compounds. Others are mixtures. The various compounds, corresponding structures, and specific uses are given. The toxicity of these products is discussed.
Chromogenic Materials, Piezochromic
Authors: Drickamer H. G. 
Published: August 2004

Abstract
In its most general sense piezochromism is the change in color of a solid under compression. There are three aspects of the phenomenon: (1) the color of a solid results from the absorption of light in selected regions of the visible spectrum by excitation of an electron from the ground electronic state to a higher level. If the two electronic energy levels are perturbed differently by pressure, compression results in a color change. This is the basic definition of pressure tuning spectroscopy; (2) a discontinuous change of color occurs when a crystalline solid undergoes a first‐order phase transition from one crystal structure to another; (3) the phenomenon of most interest is a change in color of a solid as a result of a change in the molecular geometry of the molecules that make up the solid. Examples of material's piezochromic behavior and the types of transitions involved are discussed.
Plastics Testing
Authors: Furches Barbara J. 
Published: August 2004

AbstractPlastics testing covers analytical, thermal, physical, and environmental procedures for determining the composition, structure, as well as mechanical and other responses to a variety of environmental conditions of plastic materials. General uses of Fourier transform infrared, nuclear magnetic resonance, Raman, and x‐ray techniques are reviewed and illustrated with specific examples. Developments in neutron and x‐ray scattering techniques, as well as molecular weight determination techniques such as gel‐permeation chromatography and turbidimetric methods, are also covered. Thermal tests, thermogravimetric analysis, differential thermal analysis, differential scanning calorimetry, and dynamic mechanical analysis are all useful for understanding degradation and phase changes in polymers and their influence on material behavior. Several mechanical testing techniques are used in plastics for normal quality control testing and initial application screening of polymers. These tests and those used for more fundamental understanding of polymer response to stress, including fracture mechanics procedures, are referenced. Flammability tests commonly used for plastics include oxygen index, flammability ratings, and smoke generation. Work on the use of cone calorimeters to characterize behavior of plastics under fire conditions is also covered. Finally, environmental testing, chemical exposure, weathering, radiation, and biological agents are reviewed. Emphasis is given to test development or applications reported since 1980.
Plastics Processing
Authors: Xanthos M. , Todd D. B. 
Published: August 2004

AbstractProcessing of plastics comprises a variety of operations involving flow and shaping of polymer melts into finished articles. For thermoplastic resins the most common processing operations are extrusion and molding. In extrusion, solid plastic resin is melted and then shaped in a continuous part of a defined cross section by screw‐conveying and forcing the melt to flow through a die. Die forming is used in pipe and tubing, film, sheet, wire, and cable coating. Molding involves such noncontinuous processes as injection molding, blow molding, rotational molding, and compression molding, in which three‐dimensional parts are made in a closed mold. Molded products are solid, hollow, or foamed. Other thermoplastics operations include thermoforming, calendering, and casting. In contrast to thermoplastics, thermosetting resins use low viscosity components which, through chemical reaction, produce the solid part in the mold. Common processing methods for thermoset systems are compression molding, transfer molding, and injection molding. Specialized techniques developed for fiber‐reinforced thermosets include open‐mold processing, pultrusion, resin transfer molding, and reaction injection molding. Specific processing methods for making low density articles from thermoset polyurethanes are described.
Fine Chemicals
Authors: Pollak Peter , Habegger Erich 
Published: August 2004

AbstractFine chemicals are low volume, high priced chemical intermediates and bulk active ingredients primarily used in the preparation of pharmaceuticals and agrochemicals, but are also used in other specialties, such as household and personal care ingredients, electronic chemicals, and flavors and fragrances. In contrast to specialty chemicals, these intermediates are sold within the chemical industry and according to specifications rather than performance criteria. Fine chemicals typically are manufactured by batch processes in multipurpose plants starting from commodity chemicals and involving several distinct chemical or biotechnological steps. A typical fine chemical plant consists of a “wet” section, where the chemical reactions and the preliminary solid–liquid separations are carried out, and a “dry” section, where the product drying, milling, sieving, and packaging takes place. The wet section is further divided into production trains that allow individual process steps to be performed. The main apparatus are jacketed and agitated 1–10‐m3reaction vessels connected to overhead condensers, and filters resp. centrifuges. The smallest production unit is a “train”. A train consists usually of three jacketed reactors with overhead condensers, head tanks, receivers, and a filtration unit (centrifuge or nutsche). Several trains are regrouped in a production building. A complete plant also comprises an administrative building, R&D, and analytical laboratories, a pilot plant, utilities, maintenance and waste disposal units, and a warehouse.
Propylene Oxide
Authors: Trent David L. 
Published: August 2004

AbstractPropylene oxide, a commercially important chemical worldwide, is very reactive, finding application in many derivative businesses. Use is primarily as an intermediate for a wide array of products, such as polyether polyols for the polyurethane industry; propylene glycol for food, cosmetics, and heat‐transfer fluids; polyglycols as lubricants, antifoam agents, and metalworking fluids; glycol ethers for protective coatings, inks, and cleaners; and isopropanolamines for adhesives, corrosion inhibitors, and agricultural products.Propylene oxide is produced by two process chemistries. The first, and oldest, is the chlorohydrin process. Epoxidation by caustic or milk of lime produces the epoxide. The second process involves the oxidation of an organic such as isobutane or ethylbenzene to the corresponding hydroperoxide, then epoxidation of propylene using the hydroperoxide to the epoxide and an alcohol. The alcohol,tert‐butanol or 1‐phenylethanol, is further processed to provide the commercially viable coproducts, such as methyl‐tert‐butyl ether and styrene. The global capacity for propylene oxide is about half from the chlorohydrin process and a quarter each from the hydroperoxide processes producingtert‐butanol and styrene as coproducts. These and several other potentially commercial processes are discussed.
Pumps
Authors: Nelik Lev 
Published: August 2004

AbstractPumps are used in a wide range of industrial applications in the chemical processing industries. Pumping equipment varies widely in terms of pump type, size, and materials of construction. The two principal pump types, kinetic, which is mainly centrifugal, and positive displacement, are presented and basic operating parameters such as capacity, head, power, efficiency, and specific speed are defined. Fundamentals of operation are discussed, selection guidelines given, and examples of pump applications and reliability concerns provided. Pump auxiliaries such as couplings and seals, as well as effects of cavitation, recirculation, internal hydraulic forces, wear, and corrosion, are described. Cost approximation methodology is presented along with a list of manufacturers.
Antibacterial Agents, Quinolones
Authors: Reuman M. , Lesher G. Y. 
Published: August 2004

AbstractQuinolone carboxylic acids are a class of totally synthetic antibacterial agents which encompass 4‐oxo‐3‐quinolinecarboxylic acids as well as the corresponding 1,8‐naphthyridines, cinnolines, and pyrido [2,3‐d]‐pyrimidines. These classes are illustrated by ciprofloxacin, nalidixic acid, cinoxacin, and piromidic acid, respectively. Established quinolone antibacterial agents are ciprofloxacin, ofloxacin, enoxacin, norfloxacin, and pefloxacin. Quinolones exert their antibacterial activity by interfering with the replication of bacterial DNA by inhibition of the enzyme DNA gyrase. The critical reaction is the negative supercoiling of bacterial DNA, a process involving the breaking and resealing of double‐stranded circular DNA. The general method by which most newer fluoro quinolones are prepared involves a ring closure reaction to form the quinolone nucleus. For the most part quinolones are well tolerated with few reports of adverse reactions, but because of a concern that they cause arthropathy in juvenile animals, quinolones are contraindicated for children and during pregnancy. A second problem is adverse side effects of the central nervous system (CNS) and adverse reactions with other drugs. Earlier quinolones have had little impact on the domestic antiinfective market as their utility was limited primarily to urinary tract infections. Newer quinolones, because of safety, seemingly low propensity toward bacterial resistance, and vastly improved therapeutic utility, enjoy a much greater market share.
Shape‐Memory Alloys
Authors: Schetky L. McDonald 
Published: August 2004

Abstract

Shape‐memory alloys are capable of undergoing reversible phase transitions as a result of temperature, pressure, or other stress‐related changes. These materials exhibit a mechanical type of shape memory called pseudoelasticity and, under certain conditions, linear superelasticity. The recoverable strain or shape is generally

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. Whereas the alloys are primarily nonferrous, some ferrous alloys also exhibit shape memory.

Applications of shape‐memory alloys include those as tubes and valves in piping systems for power plants, ships, and the petroleum industry; use as explosive bolts in the aerospace and construction industry; as packaging devices for electronic materials; and as dental materials, prosthetics, and biomedical devices. Shape‐memory alloys may be found in sensors in automobiles, in consumer products, and generally in smart materials and adaptive structures.
Silicon Compounds, Silicones
Authors: Rich Jonathan , Cella James , Lewis Larry , Stein Judith , Singh Navjot , Rubinsztajn Slawomir , Wengrovius Jeff 
Published: August 2004

AbstractThis article begins with an introduction on common shorthand nomenclature and a history of silicones. The chemistry discussion includes a description of the direct process for formation of monomers, including the methylchlorosilane process. The silicone polymerizations described are condensations, anionic and cationic ring‐opening polymerizations, emulsions, radiation‐induced polymerizations, and plasma reactions. Discussion of silicone network formation includes those formed via peroxides, hydrosilylation, condensation, high energy, and uv radiation. Methods of characterizing silicone networks are discussed, as well as model, monodisperse, and filled networks. A section on silicone properties and uses includes discussion of fluids, heat‐cured rubber, liquid‐injection‐molding rubber, hardcoats, release coatings, and resins. A discussion of resins includes sections devoted to characterization, structure, synthesis, and applications. Room‐temperature‐vulcanized (RTV) silicones are reviewed with sections on moisture‐curable silicones, basic RTV chemistry, RTV compositions, properties, and applications. Analysis and testing of silicones are described, along with chemical analysis, instrumental methods, and determination of physical properties. Important new developments are given on health and environmental aspects of silicones. Economic aspects of the silicones industry are summarized.
Silver Compounds
Authors: Cappel C. Robert 
Published: August 2004

AbstractMost silver compounds are made from aqueous silver nitrate, which in turn is made from silver metal. Silver compounds are found in nature, but are neither ubiquitous nor prevalent. Silver salts are therefore expensive. Much of the silver produced annually in the United States comes from recycled metal. The primary usage of silver compounds occurs in the photographic industry. Silver compounds are also utilized in batteries, as catalysts, to form the reflective backings of mirrors, and for electroplating silver. Silver(I) compounds and complexes are the most stable, although some materials of higher silver oxidation are known. Some aqueous silver solutions serve as antiseptics; other as analytic reagents.
Carbon, Structure, Terminology, and History
Authors: Long J. C. 
Published: August 2004

AbstractElemental carbon, atomic number six in the periodic table, at wt 12.011, occurs naturally throughout the world in either its crystalline (more ordered) or amorphous (less ordered) form. Carbonaceous materials such as soot or charcoal are examples of the amorphous form, whereas graphite and diamond are crystalline. Carbon atoms bond with other carbon atoms as well as with other elements, principally hydrogen, nitrogen, oxygen, and sulfur, to form carbon compounds, which are the subject of organic chemistry. The manufactured form of carbon and graphite is discussed within this article. In their many varying manufactured forms, carbon and graphite can exhibit a wide range of electrical, thermal, and chemical properties that are controlled by the selection of raw materials and thermal processing during manufacture. There are two allotropes of carbon: diamond and graphite. The diamond, or isotropic form, has a crystal structure that is face‐centered cubic with interatomic distances of 0.154 nm. Each atom is covalently bonded to four other carbon atoms in the form of a tetrahedron. The nature of the bonding explains the differences in properties of the two allotropic forms. The hardness of diamond is derived from the regular three‐dimensional network of σ‐bonds. Graphite, or the anisotropic form, has a structure that is composed of infinite layers of carbon atoms arranged in the form of hexagons lying in planes. The electronic ground state of carbon is 1s2, 2s2, 2p2. In diamond, the 2sand 2pelectrons mix to form four equivalent covalent σ‐bonds. In graphite, three of the four electrons form strong covalent π‐bonds with the adjacent in‐plane carbon atoms. The fourth electron forms a less strong bond between the planes. A wide variety and range of bulk carbon forms are available within the industry. In general, commercial forms are loosely characterized as carbon or graphite, but they are distinctly different. The termmanufactured carbonrefers to a bonded granular carbon body whose matrix has been subjected to a temperature typically between 900 and 2400°C.Manufactured graphiterefers to a bonded granular carbon body whose matrix has been subjected to a temperature typically in excess of 2400°C. Natural graphite has been known since the Middle Ages, but carbon was first fabricated by H. Davy in his experiments on the electric arc in the early 1800s. The manufacture of artificial graphite came about only at the end of the nineteenth century, preceded by developments in the fabrication of electrodes. The electric resistance furnace enabled the reaching of approximately 3000°C, the temperature necessary for graphitization. A new application for graphite, its use by E. Fermi in the first self‐sustaining nuclear reaction, was followed by new fields of research and new markets opened by development of the aerospace industries, including the use of carbon and graphite fibers in composite materials.
Coating Processes, Survey
Authors: Cohen Edward D. , Gutoff Edgar B. 
Published: August 2004

Abstract
A coating replaces air at the interface of a substrate with a new material. Coatings are applied to surfaces for both functional and decorative reasons. The processes whereby the fluid that forms the coating is transferred to a substrate, which may be a stationary support or a traveling web, are reviewed. Steps in the coating process include: preparation of the coating fluid, metering the fluid to a desired coating weight, application of the coating fluid, and removal of the solvent and drying.
The relationships between such factors as the nature of the substrate, the coating fluid rheology, coating solvent, coating uniformity and speed, number of layers, and whether the coating is to be continuous or intermittent, are considered for the various coating methods. Knife, roll, blade, gravure, slot, and extrusion coaters for single‐layer coating are presented as are the slide and precision curtain methods used for multilayer coating. Dryers and drying fundamentals are also described.
Acrylic Ester Polymers, Survey
Authors: Novak Ronald W. 
Published: August 2004

Abstract
The nature of the R group in its formula determines the properties of each acrylic ester and the polymers it forms. Polymers of this class are distinguished by their water‐clear color and stability on aging. Acrylic monomers are extremely versatile building blocks. They readily polymerize or copolymerize with a variety of other monomers. Copolymers with methacrylates, vinyl acetate, styrene, and acrylonitrile are commercially significant. Although the acrylics have a higher cost than many other monomers their unique characteristics and efficiency offset the higher cost. Acrylic ester polymers can be made to hydrolyze to poly(acrylic acid) or an acid salt and the corresponding alcohol. Two principal processes are used for the manufacture of monomeric acrylic esters: the semicatalytic Reppe process and the propylene oxidation process, the latter of which is preferred because of economy and safety. The toxicities of acrylic monomers range from moderate to slight. The vast majority of all commercially prepared acrylic polymers are copolymers of an acrylic ester monomer with one or more different monomers. Copolymerization has led to the development of many different resins for a variety of applications. Acrylic polymers are considered to be nontoxic, and are used primarily in coatings, textiles, adhesives, and paper.
Tellurium and Tellurium Compounds
Authors: Hoffmann James E. , King Michael G. , Carapella S. C. , Oldfield J. E. , Putnam R. D. 
Published: August 2004

AbstractTellurium is the most metallic of the abundant chalcogens. In many of its chemical properties it still resembles oxygen, sulfur, and selenium.Tellurium is produced as a by‐product at copper refineries throughout the world. The main uses for tellurium are as a free‐machining additive in both ferrous and nonferrous metallurgy, in chemicals (30%), and in electrical applications such as solar cells and thermoelectrics. Applications of tellurium are frequently limited by the small quantities available. Tellurium and tellurium compounds generally have a low environmental impact.
Chromogenic Materials, Thermochromic
Authors: Greenberg Charles B. 
Published: August 2004

Abstract
Thermochromism is a reversible change in spectral properties as a result of heating and cooling. Usually the response is visible. It is observed in complexed metals, in both inorganic and organic materials generally, and in all phases of matter, though predominately in solids and solutions. There are thousands of examples in the solid and liquid phases, a few examples of which are given here. These examples have been selected to indicate the scope of transition mecanisms tat contribute to this interesting chromogenic materials category. The breadth of the subject is evident from the bibliography. It includes, on the one hand, literature that has been generated in the circle of the inorganic chemist, as well as references that are from the literature of the physicist and also the organic chemist. Indeed, thermochromism is an encompassing subject.