Polyamide synthetic fibers

PPG-40 diethylmonium chloride lubricant, synthetic fibers polyamides Dimethyl, methyl (polypropylene oxide) siloxane... 

Figure 38-12. Cross sections of diflerent synthetic fibers. Polyamide filaments with round (above left) and trilobal (above right) cross sections a bicomponent filament with a poly(hexamethylene diamine) core and a poly(e-caprolactam) mantle (below left) and a polyester filament with a triangular cross section (below right) (Institut fiir angewandte Mikroskopie der Frauenhofer-Gesellschaft, Karlsruhe.)...

PP fibers are the most recent synthetics to achieve commercial importance. They appeared on the fiber market in the early 1970s and represent by now the fourth major class of fibers besides the other traditional synthetic fibers polyamides (PAs), polyesters (PESs), and polyacrylics. Their starting point was the application of Ziegler and Natta s method for the production of isotactic PPs, which can be processed into films and fibers. Montecatini applied for the patents in 1954 [1, 2],... 

The information in Table 2.10 shows that NIR techniques also allow the characterization of textile products made from natural fibers (cotton, wool, blends) or from synthetic fibers (polyamide, polyester, blends). In this case, NIR reflectance spectroscopy is mostly applied, and provides the advantage of testing a sample rapidly (within minutes), without destroying its integrity. Moreover, with the aid of sophisticated commercial instruments, not only quantitative analyses but also... 

However, because of the low melting poiats and poor hydrolytic stabiUty of polyesters from available iatermediates, Carothers shifted his attention to linear ahphatic polyamides and created nylon as the first commercial synthetic fiber. It was nearly 10 years before. R. Whinfield and J. T. Dickson were to discover the merits of poly(ethylene terephthalate) [25038-59-9] (PET) made from aromatic terephthaUc acid [100-21-0] (TA) and ethylene glycol [107-21-1] (2G). 

PyraZolines. l,3-Diphenyl-2-pyia2olines (7) (Table 2) aie obtainable from appiopiiately substituted phenyUiydiazines by the Knoii reaction with either P-chloro- or P-dimethylaminopropiophenones (30,31). They are employed for brightening synthetic fibers such as polyamides, cellulose acetates, and polyacrylonitriles. 

Synthetic Fiber and Plastics Industries. In the synthetic fibers and plastics industries, the substrate itself serves as the solvent, and the whitener is not appHed from solutions as in textiles. Table 6 Hsts the types of FWAs used in the synthetic fibers and plastic industries. In the case of synthetic fibers, such as polyamide and polyester produced by the melt-spinning process, FWAs can be added at the start or during the course of polymerization or polycondensation. However, FWAs can also be powdered onto the polymer chips prior to spinning. The above types of appHcation place severe thermal and chemical demands on FWAs. They must not interfere with the polymerization reaction and must remain stable under spinning conditions. 

Sulfur dyes are used mainly for dyeing textile ceUulosic materials or blends of ceUulosic fibers (qv) with synthetic fibers such as acryUc fibers, polyamides (nylons), and polyesters. They are also used for sHk (qv) and paper (qv) in limited quantities for specific appHcations. Solubilized sulfur dyes are used on certain types of leathers (qv). 

The primary driving forces behind investigation of new solvents include environmental concerns and the abiUty to form Hquid crystals in the new solvent systems. By analogy with Kevlar, a synthetic aromatic polyamide fiber, spinning from a Hquid crystalline solution should yield cellulose fibers with improved strength, as has been demonstrated in laboratory experiments. 

It is difficult for dye solutions in water to penetrate synthetic fibers such as polyester, cellulose triacetate, polyamides, and polyacryUcs which are somewhat hydrophobic. The rate of water imbibition differs with each fiber as shown in Table 1 as compared to viscose (see Fibers, regenerated CELLULOSics), which imbibes water at the rate of 100% (1). The low imbibition rate is attributed to the high T obtained when the polymeric fibers are drawn. During this drawing operation the polymer chains become highly oriented and tightly packed, forming a stmcture practically free of voids. 

Disperse dyes are water-iasoluble, aqueous dispersed materials that are used for dyeiag hydrophobic synthetic fibers, including polyester, acetate, and polyamide. 

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). 

This particular reaction is performed on an industrial scale e-caprolactam 7 is used as monomer for polymerization to a polyamide for the production of synthetic 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... 

Polyamides are the second largest group of synthetic fibers after polyesters. However, they were the first synthetic fibers that appeared in the market in 1940. This was the result of the work of W. H. Carothers in USA who developed nylon 66. At about the same time nylon 6 was also developed in Germany by I. G. Farben. Both of these nylons still dominate the market for polyamides. However, due to patent restrictions and raw materials considerations, nylon 66 is most extensively produced in USA and nylon 6 is most extensively produced in Europe. 

Wallace Carothers and coworkers at DuPont synthesized aliphatic polyesters in the 1930s [Furukawa, 1998 Hounshell and Smith, 1988]. These had melting points below 100°C, which made them unsuitable for firber use. Carothers then turned successfully to polyamides, based on the theoretical consideration that amides melt higher than esters. Polyamides were the first synthetic fibers to be produced commercially. The polyester and polyamide research at DuPont had a major impact on all of polymer science. Carothers laid the foundation for much of our understanding of how to synthesize polymeric materials. Out of that work came other discoveries in the late 1930s, including neoprene, an elastomer produced from chloro-prene, and Teflon, produced from tetrafluoroethylene. The initial commercial application for nylon 6/6 was women s hosiery, but this was short-lived with the intrusion of World War II. The entire nylon 6/6 production was allocated to the war effort in applications for parachutes, tire cord, sewing thread, and rope. The civilian applications for nylon products burst forth and expanded rapidly after the war. 

Some of the main uses [33,34] of polyamides or nylons are for synthetic fibers for the tire, carpet, stocking, and upholstery industries. Use of polyamides as molding and extrusion resins for the plastics industry is also of increasing importance [38]. 

In February 1935, a fiber known in the laboratory as fiber 66 was produced that held promise for commercialization. The 66 refers to the number of carbon atoms in the reactants used to produce it. In the case of fiber 66, the two sixes refer to the six carbon atoms in adipic acid and six carbon atom in hexamethylenediamine, H2N(CH2)6NHr Fiber 66 was the first nylon produced. Like rayon, nylon is a generic term used for a group of synthetically produced polyamides. The name nylon was not introduced until 1938 after an extensive discussion by DuPont on what to call fiber 66. There are several versions of how the name nylon was coined, but one claims that nylon was a modification of norun (no run), which was modified into a unique name that could be used to market the product. DuPont officials had hoped to keep the name secret until the 1939 World s Fair, but leaks and patent preparation forced them to reveal the name early. DuPont did not trademark the name, but promoted the material genetically as nylon. 

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