MAN-MADE FIBRE

fibre whose chemical composition, structure, and properties are significantly modified during the manufacturing process. Man-made fibres are spun and woven into a huge number of consumer and industrial products, including garments such as shirts, scarves, and hosiery; home furnishings such as upholstery, carpets, and drapes; and industrial parts such as tire cord, flame-proof linings, and drive belts. The chemical compounds from which man-made fibres are produced are known as polymers, a class of compounds characterized by long, chainlike molecules of great size and molecular weight. Many of the polymers that constitute man-made fibres are the same as or similar to compounds that make up plastics, rubbers, adhesives, and surface coatings. Indeed, polymers such as regenerated cellulose, polycaprolactam, and polyethylene terephthalate, which have become familiar household materials under the trade names rayon, nylon, and Dacron (trademark), respectively, are also made into numerous nonfibre products, ranging from cellophane envelope windows to clear plastic soft-drink bottles. As fibres, these materials are prized for their strength, toughness, resistance to heat and mildew, and ability to hold a pressed form. Man-made fibres are to be distinguished from natural fibres such as silk, cotton, and wool. Natural fibres also consist of polymers (in this case, biologically produced compounds such as cellulose and protein), but they emerge from the textile manufacturing process in a relatively unaltered state. Some man-made fibres, too, are derived from naturally occurring polymers. For instance, rayon and acetate, two of the first man-made fibres ever to be produced, are made of the same cellulose polymers that make up cotton, hemp, flax, and the structural fibres of wood. In the case of rayon and acetate, however, the cellulose is acquired in a radically altered state (usually from wood-pulp operations) and is further modified in order to be regenerated into practical cellulose-based fibres. Rayon and acetate therefore belong to a group of man-made fibres known as regenerated fibres. Another group of man-made fibres (and by far the larger group) is the synthetic fibres. Synthetic fibres are made of polymers that do not occur naturally but instead are produced entirely in the chemical plant or laboratory, almost always from by-products of petroleum or natural gas. These polymers include nylon and polyethylene terephthalate, mentioned above, but they also include many other compounds such as the acrylics, the polyurethanes, and polypropylene. Synthetic fibres can be mass-produced to almost any set of required properties. Millions of tons are produced every year. Outline of Coverage This article reviews the composition, structure, and properties of man-made fibres, both regenerated and synthetic, and then describes the ways in which they are spun, drawn, and textured into useful fibres. For a full understanding of the material from which these fibres are made, it is recommended that the reader begin with the article industrial polymers, chemistry of. For an indication of the place occupied by man-made fibres in the overall coverage of polymers in see Industrial Polymers: Outline of Coverage. any raw, hairlike material that is used to produce yarns and fabrics and that includes fibres made by modifying natural materials (such as cellulose) and synthetic fibres made by chemical synthesis. Non-man-made fibres are called natural fibres. Cellulosic fibres are derived through chemical processing of short cotton fibres, or linters, and from wood pulp; they include rayon, acetate, and triacetate. Other materials modified to produce fibres include protein, glass, metals, and rubber. Synthetic fibres, produced from chemicals combined into large molecules called polymers, include such types as acrylic, modacrylic, nylon, polyester, and polyurethane. Individual manufacturers apply trademarked names to their own form of such fibres, such as Antron, Cumuloft, Qiana, Orlon, Dacron, and Lycra. Man-made fibres are usually produced by converting the fibre-forming substance to a fluid state, either by melting or by employing a solvent, to form a spinning liquid. In the spinning, or extruding, operation, the liquid is fed through holes in a spinneret, a device performing much the same function as the spinneret of the silkworm. In the formation of man-made fibres, the term spinning applies to the process of forcing the liquid through the spinneret holes; the same word is applied to the production of yarn by twisting together either natural or man-made fibres or combinations of both. The emerging liquid is hardened, forming a fibre having great length, called a filament, which is subjected to a stretching, or drawing, operation, increasing the alignment of its molecules. Variations and special properties can be introduced during the manufacturing process. Long filaments may be used to make yarn or may be cut into short, uniform lengths forming staple and then twisted together to form yarn. As the variety of new man-made fibres increased, as various fibres were blended together, and as special finishes were applied, fabric care presented new problems to the consumer; a trend developed employing permanent labels specifying garment care. Compare natural fibre. Additional reading Jacqueline I. Kroschwitz (ed.), Encyclopedia of Polymer Science and Engineering, 2nd ed., 17 vol. (198590), is the most comprehensive source of information on polymer science and includes articles on the major topics treated in this article; it is also available in a condensed, 1-vol. edition, Concise Encyclopedia of Polymer Science and Engineering (1990). Two additional reference works are Geoffrey Allen and John C. Bevington (eds.), Comprehensive Polymer Science: The Synthesis, Characterization, Reactions & Applications of Polymers, 7 vol. (1989); and Joseph C. Salamone (ed.), Polymeric Materials Encyclopedia, 12 vol. (1996). Books on polymer science for the nonscientific reader are Hans-Georg Elias, Mega Molecules (1987; originally published in German, 1985); and Raymond B. Seymour and Charles E. Carraher, Giant Molecules: Essential Materials for Everyday Living and Problem Solving (1990).Two good reference books on synthetic fibres are R.W. Moncrieff, Man-Made Fibres, 6th ed. (1975); and F. Happey (ed.), Applied Fibre Science, 3 vol. (197879), a very thorough source. Martin Grayson (ed.), Encyclopedia of Textiles, Fibers, and Nonwoven Fabrics (1984), compiles subject articles from the multivolume Encyclopedia of Chemical Technology. Herman F. Mark, S.M. Atlas, and E. Cernia (eds.), Man-Made Fibers: Science and Technology, 3 vol. (196768), provides in-depth reviews of selected fibres. Andrzej Ziabicki, Fundamentals of Fibre Formation: The Science of Fibre Spinning and Drawing (1976), is a treatise for the expert on fibre spinning. H.H. Yang, Nomex Aramid Fibre, in Menachem Lewin and Jack Preston (eds.), High Technology Fibers, part C (1993), pp. 77178, and Kevlar Aramid Fiber (1993), describe two types of aromatic polyamide fibres, while Yang's Aromatic High-Strength Fibers (1989), is the definitive work on the structure and property relationships for polymers used to make ultrahigh-strength, high-modulus fibres. J. Preston