Encyclopedia of Fiber & Textile Technology

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• Acetate fibers, the so-called acetate silk fibers, are man-made fibers that are molded from solutions of cellulose acetate in organic solvents. The two main types of acetate fibers are diacetate cellulose and triacetate cellulose fibers. Triacetates contain at least 92 percent acetylated cellulose groups while diacetates contains only about 76 percent acetylated cellulose groups. The diacetate fiber is officially called acetate while the triacetate cellulose is called triacetate. Acetate fibers are soft and pleasant to the touch. They are dyed only with special types of dyes, which are unsuitable for most other fibers. Triacetate fibers are less hygroscope and have a greater elasticity and wrinkle resistance than articles made of diacetate fibers.

• Acetate or disperse dyes are finely dispersed water insoluble non-ionic dye particles of low surface energy. They  directly diffuse into the fiber and thereby dye it. These dyes were developed to dye (partially) hydrophobic thermoplastic fibers such as acetate, triacetate, nylon, polyester, and acrylic. Some suitable chemical compounds for disperse dyes include coumarins, anthraquinone, methines, naphthalimides, nitrodiphenylamines and quinophthalones having no on only a few ionic solubilizing groups.¹

• Acrylic fibers are synthetic fibers made from polyacrylonitrile with an average molecular weight of about 100,000. For a fiber to be called "acrylic" in the US, the polymer must contain at least 85% acrylonitrile monomer.² Typical co-monomers are vinyl acetate and methyl acrylate. This fiber was first created by DuPont in 1941 and trademarked under the tradename Orlon. It is manufactured as a filament, and then cut into short staple length fibers similar to wool hairs, and spun into yarns. Acrylic fabrics are lightweight, soft, and warm, with a wool-like feel and, therefore, can be made to mimic other fibers, such as cotton and wool or can be blended with them.

• Air-jet spinning, also known as Vortex or fasciated yarn spinning, was first developed by Du Pont in 1960s and successfully introduced in the 1980s. The first commercially successful system employed two opposing air jets (two-nozzle air-jet or twin-jet). In this process, staple fibers are first drafted using a system of several pairs of rollers. The fibers are then threaded through the twin-jet assembly that produces a vortex in the nozzles which causes the fibers to twist, mostly on the yarn surface. Air-jet spinning is used mainly for spinning short staple fibers, particularly cotton and polyester blends.⁴

• Antistatic finishes: Many synthetic fibers have insufficient conductivity to dissipate any charge that might accumulate. This is for example the case with unfinished polyester which can collect sufficient charge on the surface to spontaneously discharge which gives rise to a spark that discharges the accumulated charge. This can result in a mild shock to the person wearing the apparel. To prevent the buildup of electric charge, synthetic fibers are often treated with an antistatic finish making the fiber conductive enough to dissipate high charge densities before sparks can form.

• Aramid Fibers are extremely resilient and heat-resistant synthetic fibers in which the fiber-forming substance is a long-chain synthetic polyamide. The fiber is produced by spinning a solid fiber from a liquid chemical blend. Aramid fibers have excellent heat resistance, very low flammability, and good chemical resistance to most organic solvents. They also have outstanding mechanical properties including a high strength-to-weight ratio, excellent dimensional stability, and outstanding abrasion resistance and tenacity (difficult to cut or fray).

• Arselon is the only fiber in the world made of polyoxadiazole polymer. The fiber can be produced via solution spinning, using a solution of the polymer in either the polymerization solvent or another solvent for the polymer.³ Arselon possesses properties very similar to those of m-aramid including high strength, excellent dimensional stability, and high heat resistance and is used for similar applications including heat resistant garments, plastic reinforcements for hoses, tires and belts, heat and chemical resistant filters.

• Azlon is the generic name for a manmade fiber in which the fiber-forming substance is composed of any regenerated, naturally occurring protein. The fiber-forming substance can be derived from various naturally occurring proteins such as skimmed milk (casein), eggs (albumin), as well as corn and soy (zein). The fiber has a soft and warm touch like cashmere, is skin-friendly, and has excellent breathability. It is also easy to dye with bright and shiny colors and high dyeing rate.