Crystalline structure of polydecamethylene terephthaloyl-di-p-oxybenzoate and the associated features of thermotropic mesomorphism of this polymer

The structure of the crystalline lattice of polydecamethylene terephthaloyl-di-p-oxybenzoate has been established. The identity period along the axis of the macromolecule includes two monomer units with a conformation differing from the completely elongated. The parameters of the rhombic cell a=53.7, b=39.9, c=57.7 A. The disposition of the chains in the cell is characterized by the presence of a skewed layer which unites the exits of the end phases of the mesogenic groups containing phenyl residues. This implies the possible existence of a smectic structure with the periodicity approx. 25 A. Variants of structure explaining the origin of the large elementary cell are presented.