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The thermal degradation of three poly(ester amide)s derived from glycolic acid and different o-amino acids is studied by thermogravimetric analysis (TGA) at different heating rates and the results are compared. Thermal decomposition follows a two-step reaction, the mechanism involved in each step being possible to be determined. Nonisothermal integral isoconversional methods (such as Kissinger, KAS, and Flynn-Wall-Ozawa) and linear equations and differential methods (such as the Friedman expression) were used to obtain the kinetic parameters from TGA and DTGA curves. The complete kinetic triplets are also determined by the Coats-Redfern and the invariant kinetic parameters methodologies. Hydrolytic and enzymatic degradation studies, where weight losses, intrinsic viscosity changes and NMR spectra of degraded samples are evaluated, are also undertaken. The polymers seem interesting because of their application as new biodegradable materials.

The unit cell parameters of two alternating poly(ester amide)s constituted by glycolic acid and x-amino acid units have been determined by interpretation of Xray 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. V V C 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 815-825, 2007

A new regular poly(ester amide) consisting of glycolic acid and 12‐aminododecanoic acid was synthesized by a thermal polycondensation method involving the formation of a metal halide salt. Polymerization could start in liquefied or solid phases, depending on the reaction temperature. The polymerization kinetics were investigated by isothermal and nonisothermal isoconversional methods. The reaction model was selected with both Coats–Redfern and isokinetic relationships. The activation energy was higher when the reaction took place mainly in the solid state. A compensation effect was found between the frequency factor and the activation energy. The thermal properties of the new polymer were studied as well as the isothermal crystallization from the melt state. Melt‐grown spherulites were studied by means of polarizing optical microscopy. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1199–1213, 2006