Aramid fibers synthesis

Commercially, 1,3-DNB has been used extensively as an organic intermediate for m -phenylenediamine, a chemical used in the synthesis of aramid fibers and spandex (HSDB 1994). 

Chem. Descrip. N-Cyclohexyl pyrrolidone CAS 6837-24-7 EINECS/ELINCS 229-919-7 Uses Solvent tor plating engineering plastics, esp. EMS applies. dye penetrant tor aramid fibers photo resists gas separation elec, insulating coatings chem. synthesis absorp. of sulfur dioxide and nifric acid aromafic extraction high temp, polyimide processing aid Features Superior resist, to hydrolysis... 

Knijnenberg A, Bos J and Dingemans T J (2010) The synthesis and characterization of reactive poly(p-phenylene terephthalamide)s A route towards compression stable aramid fibers, Polymer... 

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 superior properties of aramid materials were the reason why significant research effort has been devoted to their synthesis. In 1989 there were at least 100 different chemical compositions of aromatic and aromatic-aliphatic polyamides [5] and there are indications that the number has doubled until today. This fact led the U.S. Federal TVade Commission to adopt a definition for aramid designating fibers of the aromatic polyamide type in which at least 85% of the amide linkages are attached directly to two aromatic rings. The compounds corresponding to this definition that have reached commercial stage are only four (Scheme 8.1) poly(r vphenylene isophthalamide) (MPDI), poly(p-phenylene terephthalamide) (PPTA), copoly(p-phenylene-3,4-diphenyl ether terephthalamide) (ODA-PPTA), and poly[5-amino-2(p-aminophenyl) benzimidazole terephthalamide] (SVM).The process of commercialization of every compound has always been the result of a constant trade-off between properties, processability and price. 

In 1976, the Teijin Co. began with production of a copoly(p-aramide) containing a smaller amount of 4,4 -diamono diphenyl ether in addition to p-pheny-lene diamine. The incorporation of the second diamine slightly reduced the strength of the fiber, but it also had two benefits, first, only one solvent was needed for the synthesis (see below) and second, a patent war with DuPont was avoided. Later Teijin also acquired the Twaron production from the Dutch AKZO. Twaron is the trademark of a Kevlar - like poly(p-aramide) developed by AKZO in the years 1968-1978 [35, 36]. It was commercialized in 1978 under the name Arenka and later renamed. 

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