Poly(4,4r-terephthanilidealkylamide)s에 관한 연구(II) -유성학적 성질과 섬유의 성질-

Studies on the Poly(4,4r-terephthanilidealkylamid)s (II) - Rheological Properties and Fibre Performance-

The critical concentration (C*) of poly(4,4'-terephthanilidealkylamid)s (PTAA's) with methylene units more than 6 seemed to be beyond the solubility limit of H2SO4. Solution of poly(4,4'-therphthanilideadipamide) (PTAd) in H2SO4. exhibited lyotropic liquid crystalline properties. Applying shear forces on the lyotropic PTAd solution fibrillar structure was easily developed. Further, solutions of PTAd in H2SO4. exhibited non-zero yield values above C* on the plots of square root of loss modulus against square root of frequency. These yield values seemed to be invariant up to the saturation concentration(Cs), but they were abruptly increased above Cs. In general, tanδ was decreased as concentration was increased. However, in case of lyotropic systems, a slight increase of tanδ was observed in the vicinity of Cs. With increasing temperature, viscosity of isotropic and anisotropic phases was normally decreased, while that of biphases was increased. The nematicisotropic phase transition temperature (TNI) was increased as concentration was increased. On the whole, TNI estimated from rheological measurements exhibited a good correlation with that determined from polarizing microscope observations. The optimum dope concentration assessed from rheological parameters agreed well with the spinning experiments. In general, effects, of spinning and heat-treatment conditions on the mechanical properties were more pronounced with PTAd fibre spun from anisotropic dope than the other PTAA fibres spun from isotropic dope.