Nylon stockings, polyamides

The amide linkage characterizes nylons. In the first commercial nylon, nylon-6,6, R = (CH2 )g and R = (CH2 )4. Nylon-6,6 is familiar as a textile fiber (nylon stockings) and a molded plastic (see Polyamides). 

The fiftieth anniversary of the announcement of nylon as the first synthetic organic textile fiber by the Du Pont Co. on October 27,1938 was celebrated as a significant event by the textile industry in 1988 (1,2). The announcement was the culmination of the fundamental research efforts of W. H. Carothers and his team at Du Pont (3). Carothers synthesized diamines from C2 to C18 in order for them to react with a variety of aliphatic dicarboxylic acids to make polyamides for evaluation as fibers (4—10). Alicyclic and aromatic diamines and dicarboxylic acids were also included. Nylon-6,6 was ultimately selected for scale-up and development because of its favorable melting point ( 260° C), best balance of properties, and lower manufacturing cost. The pilot plant for nylon-6,6 was completed in Wilmington, Delaware, in July, 1938, and a product was introduced on the market as Exton brisdes for Dr. West s toothbrushes (2). The first nylon filament plant was built in 1939 at Seaford, Delaware, and nylon stockings went on sale on October 24,1939 only to residents of Wilmington, and then nationally, on May 15, 1940 (2). 

As mentioned in Chapter 1, the commercial development of nylons was an outcome of the fundamental researches into polymerization which were begun in 1929 by Carothers of E.I. du Pont de Nemours and Co. Several polyamides and polyesters were investigated nylon 6,6 (see later for nomenclature) was first synthesized in 1935 and was selected as the most promising fibre-forming material. Commercial production was started in 1938 nylon stockings were put on trial sale in 1939 and became generally available in the UJS.A. in 1940. The... 

Polyamide is the term used to describe polymers containing the amide group. It is also commonly known as Nylon, which was the generic name given to the material by DuPont, the company that developed this material in the 1930s. By 1940, the whole of the USA was supplied with Nylon stockings such was the impact of this material. The most common types of polyamide... 

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]. 

An additional, important, type of chain polymers is the polyamides, polyesters, and polyurethanes [195-197], Among the polyamides, nylon is a very important member. In Figure 2.38, the repeating unit of one of the member of the nylon family, that is, the repeating unit of polyhexamethylene adipamide, or nylon 6,6 is represented [8,195]. As was previously commented, nylon is applied in stockings, ropes, fabrics, and has other uses. 

Nylon 6,6, a polymer composed of many amide bonds, was the first synthetic fiber and one of the most iucrative products ever invented at DuPont. Because nyion is strong and durable, and can be spun into a fiber that resembles the silk produced by silkworms, nylon found immediate use in making parachutes, clothing, stockings, and rope. Nylon 6,6 is a polyamide that can be prepared by joining a diacid chloride and a diamine together. In Chapter 22, we learn about amides and other acyl derivatives of carboxylic acids. 

Three billion pounds of nylon and related polyamides are produced annually. About 60% of that total goes to make the nylon fiber used in home furnishings such as carpet. The remainder is used largely as a textile fiber in clothing (shirts, dresses, stockings, underwear, etc.) and as tire cord. Minor but important uses include fasteners, rope, parachutes, paintbrushes, and electrical parts (see I Figure 6.4). In medicine, nylon is used in specialized mbing. Nylon sutures were the first synthetic sutures and are still used. 

Many of the properties of natural silk are closely approached by synthetic fibers based on polyamide and polyester. Before the introduction of polyamide 6,6, the first fully synthetic fiber, high-quality women s stockings, for example, were made from natural silk and cheap ones were made from cotton. The new nylons" were silklike and quickly displaced both natural silk and cotton from the stocking material market. 

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