Rayon fibrils

Regenerated Cellulose An attempt was made to fibrillate a regenerated cellulose (1.5 denier 1-9/16 in bright Fiber 40 Rayon from Avtex Fibers Incorporated). The procedure described above was tried, but failed to fibrillate the rayon even after 10 h. Intermittent treatment of the mixture in a strong ultrasonic field did not appear helpful, and Fiber 40 rayon was not tested further. 

At the beginning of the 1980s, interest became focused on developing ACF by the steam activation of conventional carbon fibres (CF), a fibril material whose main application was to reinforce polymer matrix composites. Poly-aciylo-nitril (PAN) based ACF was first produced by Toho Rayon Co. (Japan). At the end of the 1980s, interest centred on developing ACF from inexpensive precursors such as pitch based carbon fibres. 

Figure 10.83). Some attention has also been given to lamellar [267] and folded-chain structures [268]. Examination of rayon by the electron microscope has provided ample evidence for fibrillar structure in rayon. Although the fringed fibril structure shown in Figure 10.83 appears to fit best with the tendency of some rayons to fibrillate in the wet state under certain conditions the fringed micelle structure can also account for observed properties. 

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

Figure 4.18 Cellulose structure (a) Fringed micelle (b) Fringed fibril. Source. Reprinted with permission from Dyer J, Daul GC, Rayon Fibers, Lewin M and Pearce EM eds., Handbook of Fiber Chemistry, Marcel Dekker, New York, 777, 1998. Copyright 1998, CRC Press, Boca Raton, Florida.

Current lyocell, like the almost identical polsmosic viscose rayons developed half a century ago (33), has so far proved to have similarly hmited and variable potential in the fashion textile markets for which it, and the process for making it, was designed. Whether a cheaper, high-fibrillation version would improve lyocell s prospects in nonwovens is still open to debate. 

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