Nylon
Nylon was the first truly synthetic fiber to be commercialized (1939). Nylon was developed in the 1930s by scientists at Du Pont, headed by an American chemist Wallace Hume Caruthers (1896-1937). It is a polyamide fiber, derived from a diamine and a dicarboxylic acid, because a variety of diamines and dicarboxylic acids can be produced, there are a very large number of polyamide materials available to produce nylon fibers. The two most common versions are nylon 66 (polyhexamethylene adiamide) and nylon 6 (Polycaprolactam, a cyclic nylon intermediate). Raw materials for these are variable and sources used commercially are benzene (from coke production or oil refining), furfural (from oat hulls or corn cobs) or 1,4-butadiene (from oil refining). The chemical reactions are as follows.
Fiber types are produced commercially in various parts of the world. Nylon 66 has been preferred in North American markets, whereas nylon 6 is much more popular in Europe and elsewhere. Nylon is produced by melt spinning and is available in staple, tow, monofilament, and multi-filament form. The fiber has outstanding durability and excellent physical properties. Nylons are semi-crystalline polymers. The amide group -(-CO-NH-)- provides hydrogen bonding between polyamide chains, giving nylon high strength at elevated temperatures, toughness at low temperatures, combined with its other properties, such as stiffness, wear and abrasion resistance, low friction coefficient and good chemical resistance. These properties have made nylons the strongest of all man-made fibers in common use. Because nylons offer good mechanical and thermal properties, they are also a very important engineering thermoplastic. For example, 35% of total nylon produced is used in the automobile industry . There are several commercial nylon products, such as nylon 6, 11, 12, 6/6, 6/10, 6/12, and so on. Of these, the most widely used nylon products in the textile industry are formed of nylon 6 and nylon 6/6. The others are mainly used in tubing extrusion, injection molding, and coatings of metal objects .
Nylon’s outstanding characteristic in the textile industry is its versatility. It can be made strong enough to stand up under the punishment tire cords must endure, fine enough for sheer, high fashion hosiery, and light enough for parachute cloth and backpacker’s tents. Nylon is used both alone and in blends with other fibers, where its chief contributions are strength and abrasion resistance. Nylon washes easily, dries quickly, needs little pressing, and holds its shape well since it neither shrinks nor stretches.