Copolyesteramides .9. Random 6-iminohexanoyl 12-oxydodecanoyl copolyesteramides

Random copolyesteramides composed of NH(CH2)(5)CO (6A) and O(CH2)(11)CO (12E) units were prepared by co-polymerization/condensation of 6-hexanolactam with 12-hydroxydodecanoic acid. Lactam elimination during the reactions limited the attainable 6A content to ca. 70 mol-%. The properties of the materials differ markedly from those of the isomeric O(CH2)(5)CO/NH(CH2)(11) CO random copolymers. Those with up to 20 mol-% 6A units are crystalline and essentially modified 12E polymers. Thereafter, up to ca. 55 mol-% 6A, the materials were of an intermediate, relatively homogeneous phase character, a discrete polyamide phase appearing incipiently only at still higher 6A contents. The random nature of the copolymers was confirmed by C-13 NMR spectroscopy, and IR examination showed the prevalence of amide-ester hydrogen bonding at lower 6A contents together with a degree of intramolecular sub-crystalline order in the 12E component over the range from 20-60 mol-% 6A. It is suggested that the copolymer texture in this range is largely controlled by the preferred conformation of the (CH2)(11) units of the ester component. Some properties, including the unit cell parameters, of the little-known 12E polyester, [poly(12-oxydodecanoyl)], are reported.