Structural data on regular poly(ester amide)s derived from even diols, glycine, and terephthalic acid

The crystalline structure of two sequential poly(ester amide)s derived from glycine, tereplithalic acid, and 1,6-hexanediol or 1,12-dodecanediol has been investigated using X-ray and electron diffraction and real space electron microscopy. Crystal packing shows features of both polyamides and polyesters. The structures of the two studied poly(ester amide)s are characterized by the establishment of strong hydrogen-bond interactions along a single direction. The morphology of lamellar crystals has been investigated, their high aspect ratio being consistent with the existence of a preferential crystal growth direction. A deviation from an all-trans conformation has been detected for both polymers. Differences in crystal packing have been found depending on the number of aliphatic methylene groups. In this way, orthorhombic and triclinic unit cells have been deduced for the dodecanediol and the hexanediol derivatives, respectively. Their structures are based on a different arrangement of sheets constituted by hydrogen-bonded molecular chains.