DuPont aramid production

The photodegradation of para-aramid in an 0 atmosphere allows the differentiation between the accelerated experimental photooxidative conditions from its usual daylight exposure effects. This study illustrated an estimation of the rates of photooxidation of a commercial para-aramid product (i.e., DuPont s Kevlar-29 woven fabric) based on the oxygen-18-labelled carbon dioxide ( CC and CC ) decarboxylated from the sample. The oxygen-18-labelled atoms, which are inserted in the macromolecules, were analyzed for the photodegradation processes. This technique also allows the radial l O-distribution measurement from the fiber surface toward the fiber center. 

Kwolek s task at DuPont was to find a new kind of fiber that was resistant to acids and bases and that would remain stable at high temperatures. In 1964, she discovered such a product, an aromatic polyamide that was five times as strong as steel with half the density of fiberglass. The material was given the name aramid. Aramid was later marketed under the trade names of Kevlar and Nomex . Today, aramid is one of the most widely used substances in polymer matrix composites. 

Isophthalic acid is produced from m-xylene by processes analogous to those used for terephthalic acid except that five to six times higher pressures are required. The product (m.p. 342°C) is chiefly used for the preparation of the high thermal stability aramid polymer, Nomex (Dupont), used for electrical insulation in thermally aggressive environments. 

Aramid fiber is a proprietary organic product of the E. I. DuPont Corporation, marketed under the trade name Kevlar. The variant called Kevlar 49 is most useful... 

The basic development and the first commercial introduction of these materials were done by DuPont, which continues to be the largest producer. m-Aramid fiber products (staple. 

The situation is very similar on the para side of chemistry. The first and the largest producer—DuPont—has three facilities throughout the world. The largest one in the United States produces essentially all product forms except films. Fiber is also produced in Ireland and Japan. The other producer of p-aramids is Teijin Co., which produces two basic fibers Twaron based on PPTA and Technora based on a copolymer. Twaron is produced in the Netherlands while Technora is manufactured in Japan. 

Source From DuPont Technical Guide for Kevlar Aramid Fiber, H-77848, 4/00 DuPont Technical Guide for Nomex Brand Aramid Fiber, H-52720, 7/01 Teijin Ltd., Teijinconex Heat Resistant Aramids Fiber 02.05 Teijin Ltd., High Tenacity Aramids Fibre Technora TIE-05/87.5 Akzo Nobel, Twaron—Product Information Yarns, Fibers and Pulp. 

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. 

The basic development and the first commercial introduction of aramid materials were done by DuPont, which continues to be the largest producer. MPDI fiber products (staple, continuous filament, yarn, and floe) under the trademark Nomex are produced by DuPont in the United States and Spain. The only other major MPDI producer is Teijin, with its fiber product Teijinconex produced in Japan. The situation is very similar with the PPTA manufacturers. The first and largest manufacturer, DuPont, produces essentially all product forms except films. DuPont s PPTA fibers are known under the trademark Kevlar , p-Aramid fiber is also produced in Ireland and Japan. The other producer of PPTA is Teijin Co., which produces two basic fibers Twaron based on PPTA, and Technora based on the ODA-PPTA copolymer. A small amount of p-aramid fibers (Armos and Rusar ) are produced in Russia, both being based on SVM copolymer [6]. 

Structure. Figure 23.21 shows the structure and cross-sections for an ALIVH product. The PCB consists of laser-produced blind vias. The core material is an epoxy-aramid laminate. The man-made aramid filaments are ideal to be cut with a CO2 or UV laser. If the DuPont Kevlar filaments are added, then the resulting material wiU have a very low coefficient of thermal expansion (CTE).This is useful for mounting ceramic packages and for direct attachment of flip-chip integrated circuits. The structure can be as simple as a two-sided PCB or as complex as a many-layered PCB. The vias consist of a copper-epoxy paste that connects the top and bottom copper foil. If used as a prepreg layer without copper, the vias connect the various ALIVH layer pairs into a multilayer structure. This is not a sequential build-up process, but rather a parallel build-up process. 

Kemgard Smoke suppressants flame retardants, Sherwin-Williams Ketienflex Sulfonamides, Akzo Kevlar Aramid fiber, DuPont Kodar ASA/AES, PETG, Eastman Korad Acrylic Weatherable surfacing for ABS, HIPS, and PVC, Polymer Extruded Products... 

Aramid yarns (Kevlar of DuPont, Twaron of Teijin-Twaron) are produced from poly(p-phenylene terephthalamide), PPTA (2), which is specially developed for fiber spinning and not used in any other application. DuPont had experience with poly(m-phenylene isophthalamide) in a fiber product called Nomex for high-temperature applications. The polymer is produced in dimethylacetamide and the solution is dry-spun. This cannot be done with the stiff-chain para-para analogue PPTA. The polymer does not dissolve in organic solvents. A special polymerization route had to be developed, and the discovery of lyotropic behavior of concentrated solutions in sulfuric acid then led the way to the production of a magnificent new fiber material. 

According to the US Federal Trade Commission (FCT), wholly aromatic PAs are synthetic PAs in which at least 85% of amide groups are bound directly to two aromatic rings [1]. Aromatic PAs were first introduced in commercial applications in the early 1960s by DuPont under the tradename Nomex . It is used extensively in the production of protective apparel, air filtration, thermal and electrical insulation as well as a substitute for asbestos. Later para-aramid called Kevlai was introduced in also market by DuPont in 1973. The chemical structure of the poly(p-phenylene terephtalamides) (PPPT) and the poly(m-phenylene isophtalamides) (PMPI), which are commercial aramids of great economic relevance are shown in Figure 5.1. 

The world productive capacity for the production of para-aramid was over 100 million pounds in 2010. DuPont produces about two-thirds ofthe world capacity with plants in the United States, Northern Ireland, and Japan. Akzo Nobel produces para-aramid in the Netherlands while Teijin Ltd. makes it in Japan. 

Aramid, or aromatic polyamides, were first introduced in conunercial applications in the early 1960s, with a meta-aramid fiber produced by DuPont under the trade name Nomex. This fiber, which handles similarly to normal textile apparel fibers, is characterized by its excellent resistance to heat, as it neither melts nor ignites in normal levels of oxygen. It is used extensively in the production of protective apparel, air filtration, and thermal and electrical insulation. A para-aramid fiber with much higher tenacity and elastic modulus was also developed in the 1960s-1970s by DuPont, which was the first company to introduce a para-aramid fiber, Kevlar, in 1973. A similar fiber called Twaron with roughly the same chemical structure was introduced by Akzo in 1978. 

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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