Continuous alkali filaments

Rayon. Viscose rayon, like cotton, is comprised of cellulose. In the manufacturing process, wood pulp is treated with alkali and carbon disulfide to form cellulose xanthate. Subsequently, the reaction mass is forced through a spinneret and precipitated in an acid coagulation bath as it is formed into a continuous filament. The fiber has a round striated cross-section. Rayon staple is made by breaking the continuous strands into staple-length fibers. Viscose rayon is conventionally produced in diameters varying from 9 to 43 microns. 

Silkworm silk is another protein-based fiber produced naturally by the silkworm, B. Mori or other varieties of moth, and it is the only naturally and commercially produced continuous filament. Silkworm silk fiber is composed of a fibroin core and a sericin casing, and is relatively rigid because the sericin causes the filaments to adhere to one another. After the desericin treatment (with alkali treatment) silk has high tenacity, high luster, and good dimensional stability. A triangle cross section is its typical stracture, which results in the luster of silkworm silk (Fig. 2.10). 

E glass—a calcium aluminosilicate with less than about 2 wt% alkali developed in the 1930s for electrical insulation applications. It has good electrical resistivity because of its low alkah content. Because of its excellent mechanical properties, its use has spread, particularly for glass-reinforced plastics. (Over 90 percent of all continuous-filament fiber is E glass.) However, it has poor acid durability. 

Fiberglass - Low-iron, low-alkali, low-moisture, low-cost, airfloated kaolin is used in the manufacture of continuous filament fiberglass. 

---