Nylon synthetic chemical fibers

Fibers in which the basic chemical units have been formed by chemical synthesis, followed by fiber formation, are called synthetic fibers. Examples include nylon, carbon, boron fibers, organic fibers, ceramic fibers, and metallic fibers. Among all commercially available fibers, Kevlar fibers exhibit high strength and modulus. (Kevlar is a DuPont trademark for poly [p-phenylene diamine terephthalamide].) It is an aromatic polyamide (aramid) in which at least 85% of the... 

The Japanese solution to chemical fiber overcapacities naturally involved MITI which pushed through a 17% cut in existing polyester, Nylon filament, and acrylic fiber capacities between 1978 and 1982. These were linear cuts, however, and did not restrict the range of synthetic fibers developed by each producer, contrary to the specializations that marked the second stage of Europe s approach. 

Nylon. In 1939 the DuPont Company introduced the first truly synthetic textile fiber. Dr. Wallace Carothers invented nylon as a result of his basic research into polymer science. Chemically, nylon is a polyamide fiber. The two major types of nylon polymer are used in textiles type 6,6 which is made by using hexam-ethylene glycol and adipic acid, and type 6, which is made by polymerizing e-caprolactam. Nylon fibers are made by melt-spinning the molten polymer. The result is a continuous filament fiber of indeterminate length. It is spun in many deniers, with its diameter varying from 10 to 50 microns. The cross-section usually is round, trilobal, or square with hollow channels when used as carpet fiber. 

The commonly used synthetic fiber reinforcements are aramid, Nomex , nylon, and Kevlar fibers [19]. The research and development in the fields of synthetic fiber reinforced composites led to the development of aramid fibers. Further research led to the invention of meta and /> r -aramids [20]. Para and meta refer to the positions of the carboxylic and amine groups on the monomer ring. Nomex [21] was produced in the early 1960s and its excellent thermal, chemical, and radiation resistance [22, 23] led to extensive use in defensive clothing, insulation, and as a substitute for asbestos [24]. Additional researches with this /weta-aramid (Nomex) led to the fiber recognized as Kevlar [25]. Kevlar is a / ara-aramid fiber [26]. It was produced and trademarked by DuPont and became commercially accessible in 1973. In the last two decades, the worldwide production and use of aramids has been growing steadily. 

Early examples of application of this reactive CPMD approach were the chemical rearrangement of azulene into naphthalene [62], where new mechanisms and alternative possible pathways were evidenced for the first time, the synthetic organic reactions in supercritical water for the production of nylon synthetic fibers [63], and phase transitions in various materials from zeolites to graphene [64]. 

Chemical fibers are produced from modified natural or synthetic high molecular substances and are classified as artificial ones obtained by chemical processing of natural raw material, commonly cellulose (viscose, acetate), and synthetic ones obtained from synthetic polymers (nylon-6, polyester, aciyl, PVC fibers, etc.). 

Commercial production of PVA fiber was thus started in Japan, at as early a period as that for nylon. However, compared with various other synthetic fibers which appeared after that period, the properties of which have continuously been improved, PVA fiber is not very well suited for clothing and interior uses because of its characteristic properties. The fiber, however, is widely used in the world because of unique features such as high affinity for water due to the —OH groups present in PVA, excellent mechanical properties because of high crystallinity, and high resistance to chemicals including alkah and natural conditions. 

Nylon is similar ia its general chemical stmcture to the natural fiber wool, and therefore all the previously described processes for wool are appHcable to dyeiag nylon with acid, metallised, and other dyes. There are, however, significant differences. Nylon is synthetic, it has defined chemical stmcture depending on the manufactufing process, and it is hydrophobic (see Fibers, POLYAMIDES). 

Naturally occurring fibers such as cotton, cellulose, etc., have short whiskers protruding from the surface, which help to give a physical bond when mixed with rubber. Glass, nylon, polyester, and rayon have smooth surfaces and adhesion of these fibers to the rubber matrix is comparatively poor. In addition, these synthetic fibers have chemically unreactive surfaces, which must be treated to enable a bond to form with the mbber. In general, the fibers are dipped in adhesives in the latex form and this technology is the most common one used for continuous fibers. The adhesion between elastomers and fibers was discussed by Kubo [128]. Hisaki et al. [129] and Kubo [130] proposed a... 

Polyamide fibers, 19 739-772. See also Synthetic polyamides applications for, 19 765-766 chemical properties of, 19 745-747 cross-section shape of, 19 756 dyeability of, 19 758-760 early reactive dyes for, 9 468-470 electrical properties of, 19 745 manufacture of, 19 748-749 modified nylon-6 and nylon-6,6, 19 760-764... 

Phenol is both a man-made chemical and produced naturally. It is found in nature in some foods and in human and animal wastes and decomposing organic material. The largest single use of phenol is as an intermediate in the production of phenolic resins. However, it is also used in the production of caprolactam (which is used in the manufacture of nylon 6 and other synthetic fibers) and bisphenol A (which is used in the manufacture of epoxy and other resins). Phenol is also used as a slimicide (a chemical toxic to bacteria and fungi characteristic of aqueous slimes), as a disinfectant, and in medicinal preparations such as over-the-counter treatments for sore throats. Phenol ranks in the top 50 in production volumes for chemicals produced in the United States. Chapters 3 and 4 contain more information. 

Nearly all cyclohexane is used to make three intermediate chemicals. About 85% goes for caprolactam, and adipic acid. Another 10% goes for hexamethylene diamine (HMD). All three are the starting materials for Nylon 6 or Nylon 66 synthetic fibers and resins. Nylon fiber markets include the familiar applications hosiery, upholstery, carpet, and tire cord. Nylon resins are engineering plastics and are largely used to manufacture gears, washers, and similar applications where economy, strength, and a surface with minimum friction are important. 

Approximately 750,000 tons of benzoic acid is produced globally each year. Benzoic acids greatest use is as an intermediate in the production of other chemicals. More than 90% of benzoic acid production is converted into phenol (C6H5OH, see Phenol) or caprolactam (C6HuNO). Caprolactam is used in the production of nylon and other synthetic fibers. 

Note Accdg to private communication of the late Mr George D. Clift only 1% of DuPont s activities were (as of i960) in explosives, the rest being in various chemicals, synthetic fibers (Nylon, Dacron, Orion, etc),... 

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