Alternating poly(ester amide)s of glycolic acid and ω-amino acids: Crystalline morphology and main crystallographic data

• Published in: Journal of polymer science. Part B, Polymer physics Vol. 45; no. 7; pp. 815 - 825
• Main Authors: Botines, Emma, Teresa Casas, María, Puiggalí, Jordi
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01-04-2007; Wiley
• Subjects: Applied sciences; electron microscopy; Exact sciences and technology; glycolic acid; Organic polymers; Physicochemistry of polymers; poly(ester amide)s; Properties and characterization; structure; Structure, morphology and analysis; X-ray diffraction; Polyesteramide; X-ray diffraction; Experimental study; Lattice parameters; Single crystal; structure; poly(ester amide)s; Spherulites; glycolic acid; Aliphatic polymer; electron microscopy; Crystal morphology; Hydrogen bond; Crystalline structure
• ISSN: 0887-6266; 1099-0488
• DOI: 10.1002/polb.21077

The unit cell parameters of two alternating poly(ester amide)s constituted by glycolic acid and ω‐amino acid units have been determined by interpretation of X‐ray and electron diffraction patterns. Orthorhombic unit cells containing two chain segments with a nonplanar conformation have been derived. The electron diffraction patterns were rather different from those characteristic of aliphatic polyamides and polyesters with a zig–zag conformation. Chain‐folded lamellar crystals have been obtained by isothermal crystallization of dilute diol or glycerine solutions and the crystalline habit has been studied by means of real space electron microscopy. Polyethylene decoration techniques have been applied to evaluate the regularity of the folding surfaces. Diffraction and morphologic data suggest that hydrogen bonds between amide groups were established along a single direction, which coincides with the preferential crystal growth direction. Spherulites prepared from both evaporation of formic acid solutions and melt crystallization have been also studied. Diffraction data indicate that hydrogen bonds are aligned along the spherulite radius. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 815–825, 2007