Stretching fiber-spinning technologies

Figure 4.9 Acrylic fiber structural model showing effect of stretching and relaxation. Source. Reprinted with permission from Capone GJ, Wet-Spinning Technology, Masson JC ed., Acrylic Fiber Technology and Applications, Marcel Dekker, New York, p. 96 and 99, 1995. Copyright 1995, CRC Press, Boca Raton, Florida.

The second ceUulosic fiber process to be commercialized was invented by L. H. Despeissis (4) in 1890 and involved the direct dissolution of cotton fiber in ammoniacal copper oxide Uquor. This solvent had been developed by M. E. Schweizer in 1857 (5). The cuprammonium solution of ceUulose was spun into water, with dilute sulfuric acid being used to neutralize the ammonia and precipitate the ceUulose fibers. H. Pauly and co-workers (6) improved on the Despeissis patent, and a German company, Vereinigte Glanstoff Eabriken, was formed to exploit the technology. In 1901, Dr. Thiele at J. P. Bemberg developed an improved stretch-spinning system, the descendants of which survive today. 

Bicomponent technology has been used to introduce functional and novelty effects other than stretch to nylon fibers. For instance, antistatic yams are made by spinning a conductive carbon-black polymer dispersion as a core with a sheath of nylon (188) and as a side-by-side configuration (189). At 0.1—1.0% implants, these conductive filaments give durable static resistance to nylon carpets without interfering with dye coloration. Conductive materials such as carbon black or metals as a sheath around a core of nylon interfere with color, especially light shades. 

Electrospiiming is a polymer process technique that uses electrostatic forces to uniaxially stretch a viscoelastic jet derived from a polymer solution or melt, to produce crmtinuous nanometric and micrometric fibers, typically assembled into nonwoven mats [1—3]. Advancements in proper material design, in controlling process parameters, and in the use of iimovative spinning devices, have allowed a dramatic expansion of the potentialities of the technology. 

The melt-blown spinning process stretches the polymer melt leaving the capillaries of the spinneret using compressed air stream. The fibers, randomly deposited on a conveyor belt, form a non-woven textile fabric - see the chapter entitled Melt blowing technology in this book. 

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