Textile fibers chemical constitution

Dyes are classified in accordance with either the chemical constitute or their application to textile fibers for coloring purposes. Table 1 gives this classification... 

Although fibers can be classified in numerous ways, in terms of present-day technology, they are fundamentally classified as(l) natural libers, and (2) synthetic libers. The principal natural fibers are cotton, wool. and. to a much lesser extent, silk. liax. and mohair. Synthetic tihers have made inroads into the use of all natural fibers, bul the greatest impact has occurred in connection with the latter three libers. Cotton continues to be a major textile fiber, measured in terms of billions of pounds used per year. Colton is one of the most versalile of all libers and blends well with synthetics. This is also true of wool, bul lo a somewhat lesser extent. Synthetic Fibers. Introduced in 1910 as a substitute for silk, rayon was the first artificial or synthetic fiber. Rayon, of course, differs completely in chemical constitution from silk. Rayon typifies most reconstituted or synthetic fibers, which perform almost as well and. in a number of respects, far better than their natural counterparts Some of the more recently developed synthetic libers have lilile if any resemblance to naturally available fibers and thus enlirely new types of end-producls with previously unobtainable end-qualities are available,... 

Lastly, synthetic varieties of textiles are present primarily in apparel and are either petroleum-based or blends with natural fibers. Polyester fibers, aramid fibers, acrylics, nylon, polyurethane, olefins (hydrophobic), polylactide (hydrophilic), milk protein-based fibers, and carbonization-based fibers all constitute synthetics which require some level of surface-modification. This includes nonwovens, structures bonded together by entangling fiber or filaments mechanically, thermally, or chemically. 

Asbestos constitutes several types of hydrated silicate mineral fibers. The types of asbestos, their chemical compositions, and CAS Numbers are presented in Table 3.8.1. These substances occur in nature in rocks, silicate minerals, fibrous stones, and underground mines. This class of substances exhibits unique properties of noncombustibility, high resistance to acids, and high tensile strength for which they were widely used in many products, including floor and roofing tiles, cement, textiles, ropes, wallboards, and papers. Because of the health hazards associated with excessive exposure to asbestos, the use of these substances is currently banned. 

The United States was faced with an additional problem because its market remained wide open to textile imports from developing countries. These imports constituted an indirect threat to American producers of chemical fibers. Their first reaction was to reduce their bases in Europe. Du Pont closed its acrylic units in Holland in 1978 and in Northern Ireland in 1980 the following year it ceased production of polyester thread in its Uentrop unit in Germany. Monsanto did likewise in 1979, shutting down its Nylon units in Luxembourg and Scotland and selling its acrylic fiber installations in Germany and Ireland to Montedison. 

Stains are intensively colored substances which, in small amounts, can affect the color and appearance of a textile. The term stain also denotes the discoloration caused by these intensely colored substances. From a physical-chemical point of view, it is useful to distinguish between stains and soils. A soil on a fabric constitutes a separate phase a liquid, a semisolid, or a solid. In contrast, a stain is usually caused by molecules of colored substances deposited on or in fibers. The term stain usually implies a degree of permanency not necessarily associated with soil [9]. 

---