Sequential poly(ester amide)s derived from glycine were synthesized by a two-step method, involving a final thermal polyesterification. Molecular weights were in general higher than those obtained with the previously reported synthesis on the basis of interfacial polyamidation. Polymers with stiff units like oxaloyl or terephthaloyl residues were thermally characterized and their degradability studied by using different types of enzymes. Polymers containing short diols are degradable in papain solutions, the degradation rate being higher for oxalic derivatives.

ABSTRACT:Two new sequential poly(ester amide)s (PEAs) derived from 1,4-butanediol, sebacic acid, and L-alanine (PABA8) or glycine (PGBG8) are prepared and characterized. For comparative purposes the related polyesters (PEs) 4,10 and 6,10 are also studied. The calorimetric analysis shows that the inclusion of amino acids improves the thermal properties such as the melting temperature without a significant reduction in their thermal stability. All polymers show hydrolytic and enzymatic degradability. The degradation rates of the PEAs are higher for the alanine derivative (PABA8) because of its low crystallinity and the higher specificity of the essayed proteolytic enzymes. The PEs are only degraded faster when enzymes with esterase activity are employed.