TEXTILE FIBERS
A textile fiber is a unit of matter, either natural or manufactured, that forms the basic element of fabrics and other textiles and has a length at least 100 times its diameter. Fibers differ from each other in their chemical nature, cross-sectional shape, surface contour, color, as well as length and diameter. Fibers are classified as either natural or manufactured. A natural fiber is any fiber that exists as a fiber in its natural state. A manufactured fiber is any fiber derived by a process of manufacture from any substance that, at any point in the manufacturing process, is not a fiber. Fibers can also be designated by their chemical make-up as either protein, cellulosic, mineral, or synthetic:
• Protein ibers are composed of polymers of amino acids.
• Cellulosic ibers are made of polymers formed from carbohydrates.
• Mineral (inorganic) ibers may be composed of silica obtained from rocks or sand.
• Synthetic ibers are made of polymers that originate from small organic molecules that combine with water and air.
The generic names for manufactured and synthetic fibers were established as part of the Textile Fiber Products Identiication Act enacted by Congress in 1954 . In 1996, lyocell was named as a new sub-generic class of rayon. The diameter of textile fibers is relatively small, generally 0.0004–0.002 in, or 11–50 µm. Their length can vary from about 7/8 in (2.2 cm) to, literally, miles. Based on length, fibers are classified as either filament or staple fiber. Filaments are a type of fiber having indefinite or extreme length, such as silk or a manufactured fiber. Staple fibers are natural fibers (except silk) or cut lengths of filament, typically being 7/8–8 in (2.2–28.5 cm) in length. The size of natural fibers is usually given as a diameter measurement in micrometers. The size of silk and manufactured fibers is usually given in denier (in the United States) or tex (in other countries). Denier and tex are linear measurements based on weight per unit length. The denier is the weight in grams of 9000 m of the material fibrous. Denier is a direct numbering system in which the lower numbers represent the finer sizes and the higher numbers the larger sizes; glass fibers are the only manufactured fibers that are not measured by denier. A one-denier nylon fiber is not equal in size to a one-denier rayon fiber, however, because the fibers differ in density. Tex is equal to the weight in grams of 1000 m (1 km) of the material. To convert from tex to denier, divide the tex value by 0.1111; to convert from denier to tex, multiply the denier value by 0.1111.
