1. Institute of Macromolecular Compounds of the Academy of Sciences of the U.S.S.R., 199004 Leningrad, U.S.S.R.;2. Institute of Polymer Chemistry, Polish Academy of Sciences, Zabrze, Poland
Abstract:
Hydrodynamic (sedimentation, diffusion and viscometry) and optical [flow birefringence (FB)] properties of solutions of p-aromatic copolyesters obtained by the polycondensation of three components with various molar ratios of N, D and T, have been investigated. Independent methods of quantitative evaluation of the parameter of equilibrium rigidity, the length of the statistical Kuhn segment, for the most rigid of copolymers soluble in tetrachloroethane with the molar ratio of components N:D:T = 0.7:0.3:1 gave the values of A = 160·10?10 m (translational friction) and 180·10?10 m (FB). The equilibrium chain rigidity of an insoluble p-aromatic polyester containing no D component, ensuring chain flexibility and polymer solubility, was evaluated from the dependence of birefringence on copolymer composition. The value of the statistical Kuhn segment obtained in this case A = (500–800)·10?10m is close to that for the most rigid aromatic polyamide-poly-p-benzamide.
