Hydrolytic and enzymatic degradation of copoly(ester amide)s based on l-tartaric and succinic acids

Abstract

The hydrolytic and enzymatic degradation of a series of crystalline copoly(ester amide)s derived from l-tartaric and succinic acids, 1,6 hexanediamine and 1,6-hexanediol with ester/amide groups ratios 3/97, 10/90, 15/85 and 20/80 was investigated. The hydrolytic degradation study was carried out at 37°C in buffered solution at pH 7.4. Changes taking place in sample weight, molecular weight, chemical constitution and thermal properties of the polymer were evaluated. Degradation proceeded with a notable increment in crystallinity and entailing slight but significant changes in the T g and T m temperatures. It was found that copoly(ester amide)s degraded faster than the parent poly(hexamethylene-di- O-methyl- l-tartaramide) and that the rate of degradation increased with the content in ester groups. It was also showed that degradation is accompanied by formation of cyclic succinimide units indicative of a scission mechanism based on the occurrence of intramolecular imidation reactions. The enzymatic degradation of these copoly(ester amide)s with papain was comparatively examined for a preliminary evaluation of their potential biodegradability.