Lyotropic Liquid Crystalline Behaviour of Aromatic Polyamides(I) -Factors Affecting the Critical Concentration of Sulfuric Acid Solution of Poly($\rho$-phenyleneterephthalamide)-

방향족 폴리아미드 용액의 액정 특성(I) -Poly($\rho$-phenyleneterephthalamide) 황산용액의 임계농도에 영향을 미치는 인자-

Several poly(ρ-phenyleneterephthalamide)s (PPD-T's) with different molecular weights were prepared. The molecular weight of PPD-T was assessed by the inherent viscosity, and the viscosity of the solution of PPD-T in sulfuric acid was measured with a Hake viscometer. The factors affecting the critical concentration of liquid crystal formation was investigated. The critical concentration was increased with increasing temperature but reduced with increasing the inherent viscosity of PPD-T. The viscosity of anisotropic phase was increased with increasing temperature and gave negative values of flow activation energy. Above the critical concentration, a nematic liquid crystalline texture was developed.