bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polybutadiene
Authors: Halasa Adel F. , Massie J. M. 
Published: July 2004

AbstractThe discovery of rubbery elastomers based on 1,3‐butadiene and its derivatives was made in 1926. I. G. Farben developed a process to use sodium polymerization on a commercial scale. The resulting polymer, Buna, made from butadiene and natrium, was tested in passenger car tires, and the results were fairly encouraging since it showed equivalent wear properties to natural rubber compounds.The work on emusion polymerization of butadiene and copolymerization of butadiene and styrene or acrylonitrile began in the 1920s in the United States under the government established Rubber Reserve program. Under this program, Gr‐s and SBR became general‐purpose rubbers even though their tire properties were inferior to natural rubber compounds. Great improvements were made in the emulsion polymerization of 1,3‐butadiene and isoprene, especially with the discovery of chain‐transfer agents used for molecular weight control. Nevertheless, the search for a natural rubber replacement continued in many research laboratories worldwide especially in the United States.
Fibers, Polyester
Authors: Hansen S. M. , Sargeant P. B. 
Published: July 2004

AbstractPolyester fiber is the largest volume, most versatile synthetic fiber in the world. Useful textile fibers of poly(ethylene terephthalate) (PET) were invented in the 1940s and commercially introduced by Du Pont and ICI in the 1950s. A broad range of PET processing options allows the fiber to be engineered for a variety of uses by modifying the filament size, cross‐sectional shape, polymer molecular weight, tensile strength, composition, dyeability, luster, and color, as well as other fiber properties. PET is produced by ester interchange of dimethyl terephthalate and ethylene glycol to form monomer, or by direct esterification of terephthalic acid with ethylene glycol to form oligomer. The low molecular weight monomer or oligomer is polycondensed at high temperature and reduced pressure to form PET polymer.Polyester is melt‐spun over a wide range of spinning speeds depending on the desired use. The mechanical and thermal properties of PET fiber are affected by the degree of molecular orientation and crystallinity, which depend on the fiber formation process used. At low spinning speeds, fibers are usually further drawn to obtain useful tensile properties. At high spinning speeds, useful PET yarns can be obtained directly. Additional processing steps, including drawing, thermal treatment, texturing, and others, significantly influence the fiber physical properties and applications.
Polymers Containing Sulfur, Polysulfones
Authors: El‐Hibri M. Jj 
Published: July 2004

Abstract
This article discusses the synthesis, properties, fabrication, and uses of aromatic polysulfones. These polymers are a class of high performance amorphous thermoplastics characterized by high glass‐transition temperatures, good mechanical strength and stiffness, and excellent thermal and oxidative resistance. They are used in a broad range of engineering applications and continue to find new uses as demands for high temperature plastic materials proliferate. The characteristic structural feature of these polymers is the presence of the para‐linked diphenylsulfone group as part of the backbone repeat unit. Emphasis of the discussion is placed on the three commercially available polysulfones, ie, those based on the polycondensation of 4,4′‐dihalodiphenylsulfone with bisphenol A, 4,4′‐dihydroxydiphenylsulfone, and 4,4′‐dihydroxydiphenyl, respectively. Polymerization techniques discussed include nucleophilic and electrophilic polycondensation routes. Property discussions touch on structure and property relations, thermal, physical, and mechanical properties, as well as other performance characteristics. Blendability of polysulfones with other polymers is also briefly discussed. Applications and uses for polysulfones are described as they pertain to specific resin performance features. Also included is information about commercial sources and costs for these materials.
Polyhydroxy)benzenes
Authors: Leston Gerd 
Published: July 2004

AbstractThis article describes the tri‐, tetra‐, penta‐, and hexahydroxybenzenes. The tetra‐, penta‐, and hexahydroxybenzenes are also referred to as benzenetetrols, benzenepentol, and benzenehexol, respectively, and the trihydroxybenzenes are more familiarly known by their trivial names, ie, pyrogallol (or pyrogallic acid), hydroxyhydroquinone, and phloroglucinol, for the 1,2,3‐, 1,2,4‐, and 1,3,5‐isomers, respectively. Included are their syntheses, manufacture where applicable, and occurrence. Physical properties, analyses, chemical properties, uses, and toxicity data are described. The chemistry of the (polyhydroxy)benzenes is presented as is that of their derivatives. Related compounds having the basic structure of the various (polyhydroxy)benzenes are also described. Included are their occurrence and chemical and physiological properties. Most of the physiological activities and uses of the (polyhydroxy)benzenes are attributable to their oxidation–reduction potentials; these compounds are strong reducing agents, useful in photographic developers, photosensitive compositions, hair dyes, and chemical analyses. The benzenepolyols and their derivatives have found use in virtually all phases of chemistry: synthesis, antioxidants, heat and light stabilizers, pesticides, in polymers, resins, and adhesives, pharmaceuticals, cosmetics, and food additives, etc.
Polypropylene
Authors: Lieberman Richard B. 
Published: July 2004

AbstractPolypropylene is one of the most widely used thermoplastics, accounting for one‐sixth of total consumption. Many automobiles, textile appliances, and other everyday items contain substantial amounts of these polymers. The ability to manufacture a broad variety of polypropylenes having properties tailored for specific applications is the primary factor in its widespread use. Comonomers, usually ethylene, are often used to provide impact‐modified or lower melting polymers. The types of polymers produced, processing methods, and end use are discussed.Highly stereoselective Ziegler‐Natta catalyst systems are the basis for all propylene polymerization processes. The development of these catalysts, from the early TiCl3systems to the modern, high yield MgCl2‐supported systems, including polymerization mechanisms, is discussed. These catalysts enabled the evolution of these polymerization processes from the early slurry process, to the current liquid monomer or gas‐phase processes. In the future, metallocene catalysts may provide further commercial advances. The Spheripol and Unipol processes are the most notable of the many processes discussed. The large expansion in polypropylene production in the late 1980s was facilitated by the availability of this newer, less costly technology. This expansion, well in excess of growth in consumption, caused a dramatic reduction in polypropylene prices in the 1990s. This expansion was most dramatic in the Far East, where few polypropylene plants existed outside Japan before 1985.
Fluorine‐Containing Polymers, Polychlorotrifluoroethylene
Authors: Millet G. H. , Kosmala J. L. 
Published: July 2004

AbstractPolychlorotrifluoroethylene (PCTFE) is typically manufactured in a suspension or emulsion polymerization process under relatively mild conditions followed by work‐up procedures, primary coagulation, and washing, to remove residual impurities from the polymer. The resulting fluoropolymer is a high molecular weight fluoroplastic with outstanding thermal and chemical resistance properties. Typical use temperatures range from −240 to 200C; contact with halogenated solvents, ethers, and esters should be avoided. The polymer is supplied in either powder or pellet forms, suitable for a variety of plastic melt processing techniques such as compression and injection molding or extrusion processes. The processing temperatures required are usually above 275C, and chrome‐plated equipment should be employed. The molded or extruded parts can be further refined by a variety of machining processes. This specialty plastic exhibits a combination of unique physical properties that include ultralow moisture vapor transmission and outgassing, oxygen compatibility, cryogenic temperature capability, electrical insulation, resistance to cold flow, good radiation resistance, and low coefficient of thermal expansion.
Polyethers
Authors: Owens Kathryn , Kyllingstad Vernon L. 
Published: July 2004

AbstractSix commercially produced largely amorphous polyether elastomers are described. These are polyepichlorohydrin, poly(epichlo‐ rohydrin‐co‐ethylene oxide), poly(epichlorohydrin‐co‐allyl glycidyl ether), poly‐ (epichlorohydrin‐co‐ethylene oxide‐co‐allyl glycidyl ether), poly(propylene oxide‐co‐epichlorohydrin‐co‐allyl glycidyl ether), and poly(propylene oxide‐co‐allyl glycidyl ether). Structure and properties including molecular weight and solution behavior for the raw polymers are discussed. Laboratory and commercial prepayration of the polymers are described. Large‐scale polymerization employs a continuous process with the reactants either in solution or as a slurry. Mixing and milling procedures are described in the commercial processing and fabrication section. Compounding information including the use of curing systems, stabilizers, antioxidants, fillers, and plasticizers is presented as well as physical properties and uses of vulcanizates of these polymers. Health and safety considerations pertaining to handling of the constituent monomers, curing systems, and raw polymers are discussed. Economic aspects are described.
Polymers
Authors: Rosen Stephen L. 
Published: July 2004

Abstract
Polymers are the materials from which plastics, rubbers, and most fibers, surface coatings, and adhesives are made. Biopolymers are important constituents of living organisms. Polymers are classified as thermosets or thermoplastics according to their response to temperature, as addition or condensation polymers according to their mode of synthesis, or as linear, branched, or cross‐linked according to their molecular structure. The microscopic structure of a polymer ultimately determines its macroscopic properties. Important structural features include molecular weight, stereoisomerism, and degree of crystallinity. The glass‐transition temperature and crystalline melting point are key parameters in determining a polymer's applications. The structure of polymer molecules is determined by the polymerization mechanism, either step‐growth (condensation) or chain‐growth (addition). Step‐growth polymerizations generally require high conversions and a close approach to stoichiometric equivalence to achieve high molecular weights. Free‐radical addition is used to manufacture a wide variety of polymers through bulk, solution, suspension, and emulsion processes. Ionic addition permits the synthesis of block copolymers and polymers of uniform molecular weight. Heterogeneous addition (Ziegler‐Natta) polymerization provides control of the steric structure of the polymer.
Polyesters, Unsaturated
Authors: Nava Hildeberto 
Published: July 2004

Abstract
Unsaturated polyester resins have been used commercially since the 1940s, establishing markets for reinforced composite plastics derived from combinations with glass‐fiber reinforcements. The availability of a wide variety of raw materials has encouraged the emergence of a diverse range of resins specifically tailored for many unique products. Fiberglass‐reinforced plastics (FRP) technology facilitates the production of large fabricated products, such as chemical and petroleum storage tanks, and a wide range of marine craft, where low cost ambient processing provides competitive advantages. The technology has also evolved for high temperature automatic molding of high volume body components used for automobiles, trucks, and recreation vehicles. Polyester resins are also used extensively in highly filled cast products for kitchen and bathroom countertop applications; polyester polymer concrete provides corrosion‐resistant surfacing for highways and bridges. High performance resins are formulated to provide optimal corrosion and thermal performance in composite products designed for the chemical process industries. Under the mandates of the U.S. Clean Air and Clean Water Regulations, FRP pipe has emerged as a cost‐effective solution to upgrade inner‐city sewer systems, and FRP duct and scrubber systems are used widely in the pulp, paper, and electrical power industries to contain noxious emissions.
Polyisoprene
Authors: Senyek Michael 
Published: July 2004

AbstractEver since a syntheticcis‐1,4‐polyisoprene with the structure and properties of natural rubber was prepared in 1954 with the then newly discovered Ziegler catalyst, synthetic polyisoprene has been an important elastomer. Various catalysts have been used for synthesizing polyisoprenes, and the two commercially important systems are Ziegler‐Natta and anionic. The manufacture ofcis‐1,4‐polyisoprene and its compounding into formulations useful in making finished goods and articles are discussed. World plant capacities and estimated production figures forcis‐1,4‐polyisoprene are given, along with current polymer cost.trans‐1,4‐Polyisoprene is produced commercially only in Japan. Some of the specifications forcis‐1,4‐polyisoprene (Natsyn) made by The Goodyear Tire & Rubber Co., the sole United States producer, include volatile matter, extractables, ash, and Mooney viscosity. The principal use forcis‐1,4‐polyisoprene is in tires and tire products, and fortrans‐1,4‐polyisoprene is in golf ball covers and orthopedic devices.
Polyaluminum Chlorides
Authors: Siefert Kristine S. 
Published: July 2004

AbstractAluminum chloride hydroxide, AlCl(OH)2, AlCl2(OH), products, commonly known as polyaluminum chlorides (PAC), are used for a wide variety of industrial applications. Other names for PAC are basic aluminum chloride, polybasic aluminum chloride, aluminum hydroxychloride, aluminum oxychloride, and aluminum chlorohydrate. The presence of polymeric, aluminum‐containing cations, the distribution of which can differ greatly, typifies PAC products. Commercially, PAC has been used in water and wastewater treatment in Japan, the former USSR, and Europe since about 1970, and in the United States since the early 1980s. Aluminum chlorohydrate, Al2Cl(OH)5, a specialty PAC product, has been utilized as an antiperspirant for over 50 years. Physical and chemical properties of the numerous PAC products can vary considerably. PAC products are usually aqueous solutions, although solid products are also sold. Solutions range from colorless to amber and from clear to hazy in appearance. A generic manufacturing process for PAC involves the addition of base to aluminum chloride solution. A common process for the manufacture of aluminum chlorohydrate involves the addition of metallic Al to aluminum chloride. Liquid polyaluminum chloride is acidic and corrosive to common metals. Suitable materials for construction of storage and handling facilities include synthetic rubber‐lined steel, corrosion‐resistant fiber glass‐reinforced plastics (FRP), ceramics, tetrafluoroethylene polymer (PTFE), and others. Polyaluminum chloride products used in the treatment of potable (drinking) water must be approved by the National Sanitation Foundation (NSF). Aluminum chlorohydrate for topical use as an antiperspirant is regulated by the FDA.
Polymers, Environmentally Degradable
Authors: Swift Graham 
Published: July 2004

AbstractEnvironmentally degradable polymers are a new technology being developed in response to polymer waste‐management, effects of which are threatening to consume valuable landfill sites and are detracting from the aesthetics of land‐ and seascapes. These polymers are one of a range of technologies that are addressing the problem; others include recycle, incineration, and continued landfill. Environmentally degradable polymers include water‐soluble polymers and plastics and degrade by oxidation, hydrolysis, irradiation (photodegradation), and biological pathways. The principal opportunities for this technology are in the niche markets for plastic used in food packaging, agriculture, hygienic products, and other applications with difficult‐to‐recover options; and for water‐soluble polymers in general, which are not sufficiently readily recoverable for one of the alternative disposal technologies to be of value.
Polychloroprene
Authors: Witsiepe W. K. 
Published: July 2004

AbstractPolychloroprene has been in commercial use for over 60 years, but continues to be the elastomer of choice for dynamic applications requiring moderate heat and oil resistance, or where long‐term environmental resistance is required. The material is manufactured by emulsion polymerization of 2‐chloro‐1,3‐butadiene. The properties of the product can be optimized for specific end uses by selection of polymerization conditions, by use of comonomers such as 2,3‐dichlorobutadiene and methacrylic acid, and by choice of the method used to control molecular weight. The kinetics of the polymerization process and the structure of the polymer have been studied in detail and related to polymer properties. Commercial products vary widely in properties depending on the intended end use and the details of the manufacturing process. Tough crystalline or ionomeric polymers are preferred for adhesive applications, whereas softer, more flexible polymers are preferred for mechanical goods applications. The latter polymers may be compounded and fabricated by substantially all the techniques used for manufacture of rubber goods by molding, extrusion, or calendering operations. Lattices are used for various bonding and adhesive applications as well as for dipped goods requiring toughness in the unreinforced film.
Potassium
Authors: Chiu Kuen‐Wai 
Published: July 2004

Abstract
Potassium, the third element in the alkali metal series, is manufactured by a reduction process using sodium and potassium chloride, operated at high temperature. Sodium chloride is the by‐product.
Potassium is itself a powerful reducing agent and can serve as an electron source for many chemical reactions. It forms liquid–metal alloys with other alkali metals. The potassium–sodium liquid alloys are ideal for use as heat‐transfer, electrical contact, and hydraulic fluids.
Commercially important potassium derivatives prepared from potassium metal include potassium–sodium alloys, alkoxides, amides, hydride, graphite, and superoxide. Most are utilized as reducing agents. A potassium–sodium dispersion provides higher reaction surface and allows reduction at lower temperatures than the individual metals. Potassium alkoxides are strong, nonnucleophilic bases that have good solubilities, selectivities, and stabilities, and are ideal for deprotonation reactions. Potassium graphite, an intercalation compound, can serve as a solid reducing agent. Potassium superoxide, a radical anion, is a strong oxidizing agent, generating oxygen in contact with moisture and carbon dioxide.
Fluorine Compounds, Inorganic, Potassium
Authors: Papcun John R. 
Published: July 2004

AbstractThe two stable forms of potassium with fluorine of commercial significance are the normal fluoride and potassium bifluoride. Potassium fluoride is used in the manufacture of silver solder fluxes and in fluxes for various metallurgical operations. Polyurethane foams can be formed with KF and it is used as a catalyst for the reaction of adiponitrile carbonate and a polyester polyol. Potassium bifluoride is used in the electrolyte for cells in fluorine manufacture, and fluxes for a wide variety of metal joining applications utilize KHF2, usually in combination with potassium pentaborate, boric acid, and other fluorides and chlorides. Physical and chemical properties are discussed.
Powder Metallurgy
Authors: Johnson Peter K. 
Published: July 2004

Abstract
Johnson, Peter K. (Metal Powder Industries Federation, APMI International). Powder metallurgy uses metal powder as the raw material to manufacture products, especially precision metal shapes and parts. The process is cost effective in producing simple or complex parts at or very close to final dimensions. These parts are finding increasing consumer and industrial applications in automobile engines and transmissions, aerospace hardware, home appliances, power tools and hardware, computer disk drives, and surgical implements.
Powder metallurgy products include tungsten lamp filaments, self‐lubricated bearings, various magnet, tools, metal‐matrix composites, and electrical components. Use of the technology continues to grow in importance. Superalloys intermetallics, and nanoscale powders are all formed from powder techniques. Processes for producing metal powders are reviewed, and powder characteristics, are discussed.
Basically a chipless metalworking process, powder metallurgy typically uses more than 97% of the starting raw materials in the finished part. The new‐shape advantage makes it a process of choice for precision metal components at reduced manufacturing costs. Various production processes for consolidating metal powders into shapes such as traditional compacting and sintering, rapid solidification, cold and hot isostatic pressing, metal injection molding, powder forging and rolling, and spray forming are reviewed.
Printing Processes
Authors: Taggi Arthur J. , Walker Peter 
Published: July 2004

AbstractThe role of chemical technology in printing processes is changing. These changes are driven by cost, convenience, and environmental pressures. Rapid advances in alternative media and computer technology are enabling the incorporation of electronic processes into the printing workflow to meet industry cost and performance needs. Elements of the printing process from image creation, capture, assembly, storage, movement, approval, duplication, output, and distribution are examined. The continuing role of chemical printing processes such as lithography, flexography, letterpress, screen printing, and thermal printing, as well as the various media and inks employed, is described. The opportunities provided by electronic technology are also presented. The newer electronic digital processes involve consumable materials that are based on chemical systems more suited to the changing needs of the printing industry. The new digital systems capabilities are discussed in terms of their impact on industry practices and workflow. Technologies that are changing the nature of the printing industry include thermal imaging, electrophotography, and ink‐jet printing.