High-tenacity rayon

Cotton Cuprammonium Regular rayon viscose rayon High-tenacity viscose rayon Saponified acetate rayon Cellulose acetate (secon- dary) Cellulose tri- acetate... 

It is generally accepted that, all other things being equal, the lower the secondary creep, the better the fiber is in terms of wear, shape retention, and crease resistance. This does not mean that glass, which has no secondary creep, is better in abrasion resistance than high tenacity viscose rayon, which has secondary creep, because the respective energy absorption capacities of these two materials, exclusive of secondary creep, are not equal. Nor does it mean that fibers that exhibit secondary creep are of no value. For fabrics to meet the requirements of wear, crease resistance, and shape retention, the load and extension yield points should not be exceeded during use. 

Table 7. Grafting of styrene onto cellulose by mutual irradiation method. (Cellulose High tenacity rayon (P v = 293) Monomer mixture Styr. MeOH H20 = 20 72 8 polymerization = 50 °C in vacuum, 20 hr (2 x 10s rad)]...

Interest in the manufacture of different forms of rayon has resulted in the production of regular rayon, hollow viscose, spun-dyed filaments and staple rayon, crimped rayon and surface modified fibers, high tenacity rayon and high wet modulus (polynosic) rayon fibers. In chemical composition, viscose rayon and cotton are alike they are both cellulose. 

The differences between regular and high-tenacity rayon are to be found in the degree of degradation of the cellulose which has occurred during preparation of the viscose, the degree of crystallization, the size of the crystallites, the degree of orientation and the fine structure and uniformity of the filament. 

E.D. Pa. 1992), where the federal government ownership of installations, equipment, and pipehnes associated with a high-tenacity rayon plant made the government Uahle as an owner for cleanup costs and E.I. du Pont de Nemours v. United States, 365 F.3d 1367,1372 (Fed. Cir. 2004), where the federal government was hahle for CERCLA costs under an open-ended contract indemnification clause in the contract with the owner and operator of the ordnance plant. 

Washing, bleaching, and twisting into cords follow. The rayon fibers can be drawn or stretched up to 100% of their original length to enable crystalline orientation to produce a high-tenacity rayon suitable for tires. 

Figure 6.10 Effect of hydrogen chloride vapor on weight loss during pyrolysis of continuous filament high tenacity rayon fiber from Teijin Co. Source Adapted from Shindo A, Nakanishi Y, Soma I, Carbon Fibers from Cellulose Fibers, AppI Polym Symposia, No 9, 271-284, 1969.

High-tenacity rayon is produced by stretching the fibers so that the molecular chains run parallel to the filament axis and a number of small crystalline regions act as anchors for the cellulose chains. Tire cord stretched in this way has greater tensile strength. 

As modifiers, PEGs improve cellulose filaments by giving them an all-skin structure with reduced swelling tendency and higher wet and dry strength. These properties are required for industrial rayon for car tires, for high-tenacity textile rayon, and for high-tenacity rayon staples. 

Nylon is used extensively today for reinforcement in bias truck, bus, off-the-road, and other tires used in the construction industry. Nylon historically took the place of rayon because of its superior fatigue resistance, high tenacity, and toughness. DuPont was granted the original patent for the synthesis of nylon-6,6 in 1935. 

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