Fragments of Heterocyclic Copolyamide Phase Diagrams

Fragments of a ternary phase diagram of the system heterocyclic copolyamide—DMAA/LiCl—precipitant (H₂O and isobutanol) are obtained. The temperature—concentration boundary of the phase transition for sulfuric-acid solutions of the heterocyclic copolyamide in the region of the existence of isotropic and anisotropic phases is determined. A hypothesis is advanced concerning the relatively high thermodynamic rigidity of the copolyamide molecules, close to the rigidity of PABI but less than the rigidity of PPTA.