Polynosic fiber

Polynosic fibers were produced for a time in several countries, including France, the United States, and Japan, but it soon became evident that they were too brittle for the textile market. Research workers soon began to modify the viscose and spinning conditions to produce several versions of hybrid fibers. 

About the same time when the polynosic fibers were developed in Japan, the producers of high-strength tire yam successfully adapted the process to produce staple fiber. These fibers had good dry and wet strength and wet-moduli sufficient to overcome the stretching and... 

In contrast to cotton, the normal viscose fiber has a strongly diminished dimensional stability, which can be traced back in part to the low molecular weight and in part to the poorer orientation of the cellulose chains. In the new modal fibers (polynosic fibers and high-wet-strength fibers), both factors are improved by the following precautionary procedures. The... 

Polynosic fiber n. A high-wet-modulus rayon staple having a microfibular structure of fibers. The molecular chain length of the cellulose forming the fiber is about twice as long as in conventional rayon. 

High wet modulus (HWM) viscose fibers Polynosic-fiber 27-44 48,49,75,76,78... 

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. 

FIGURE 10.86 Rayon fibers showing fibrillation on treatment with nitric acid (a) high wet-modulus (b) crimped HWM and (c) polynosic. 

The fibers that were produced were given wide recognition, especially in France where the name polynosics originated. They had a unique fibrillar structure, high strength wet and dry, low elongation (8 11%), relatively low water retention, and very high wet-modulus of 1 g/den (0.9 cN/dtex). Their resistance to caustic soda was exceptional for rayon in fabrics, they had the firm, crisp hand of cotton. 

Normal fibers Crimped fibers High-wet-strength fibers Polynosic modal fibers... 

The polynosic rayons enjoyed a revival of fortimes in the 1990s when the new lyocell fiber produced by Courtaulds (Tencel )—a solvent spim fiber with polynosic properties— became popular in ladies apparel and denim. By 2001 however the Toyobo Tufcel plant in Japan had been closed and at the time of writing, it is likely to be transferred to China where lower labor costs would allow it to compete more effectively with lyocell (see below). 

Regenerated fiber viscose, polynosic, cuprammonuium, acetate rayon, Tencel... 

Fibers performance Lyocell Normal viscose fibers Polynosic Modal Cuprammonium Cotton Polyester... 

High-wet-modulus rayons (polynosic rayons) have been developed in recent years. These fibers are produced from high-grade cellulose starting materials, and the formation and decomposition of cellulose xanthate is carried out under the mildest of conditions to prevent degradation of the cellulose chains. 

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