Synthesis and properties of a thermotropic copolyester based on 4‐hydroxyacetophenone azine

The synthesis of a thermotropic copolyester based on 4‐hydroxyacetophenone azine (1) and a 50 : 50 (mole ratio) mixture of sebacoyl/dodecanedioyl dichlorides was investigated in chloroform via a low‐temperature solution route. Polymers with an inherent viscosity ηinh between 0,27–1,56 dL · g−1 were characterised by 1H NMR, IR, thermal analyses, gel permeation chromatography and static light scattering techniques: Enantiotropic polymers exhibit a large mesophase range (≈100°C) and the values of both crystal‐nematic and nematic‐isotropic transitions are molecular‐weight dependent. Intrinsic viscosity was determined to relate to molecular weight by [η]/(dL · g−1) = 9,6 · 10−4 M̄ in chloroform at 25°C, and the persistence length was calculated to be of the order of 27 Å.