PREPARATION OF HIGH-STRENGTH HIGH-MODULUS REGENERATED CELLULOSE FIBERS FROM LYOTROPIC MESOPHASES

Cellulose triacetate (CTA) fibers were spun from a 35% (w/v) solution of CTA (molecular weight, 95,000) in trifluoroacetic acid (TFA)/CH(2)C L(2) (60/40, v/v) using laboratory-scale spinning equipment, an air ga p, and cold MeOH as the coagulant. The resulting fibers, of large diam eter (ca. 80 mu m) were saponified with a variety of reagents. The reg enerated cellulose fibers had tenacities and moduli as high as 1.6 and 50 GPa, respectively. The fiber properties did not show a dependence on which cellulose polymorph was present. It is suggested that, for hi ghly oriented fibers, the cellulose molecular weight is the primary pa rameter that determines the strength and modulus. This emphasizes the advantages of using a lyotropic cellulosic mesophase which permits rel atively low solution viscosities at high concentrations and high polym er molecular weights. (C) 1995 John Wiley & Sons, Inc.