FURTHER-STUDIES ON BIODEGRADATION OF ALIPHATIC POLY(ESTER-AMIDES)

Two types of aliphatic poly(ester-amides) (PEAs) were subjected to mic robial degradation in basal mineral salt broth, under the attack of a yeast, Cryptococcus laurentii, at 20 degrees C. PEA-I copolymers were made by the anionic ring-opening copolymerization of of epsilon-caprol actone and epsilon-caprolactam, whereas PEA-II copolymers were synthes ized by a two-step polycondensation reaction of hexanediol-1,6, hexane diamine-1,6, and adipoyl chloride. These copolymers were found to be r eadily degradable under biotic conditions, based on weight loss, GPC, NMR spectroscopy, and tensile property measurements. Compared to abiot ic hydrolysis, biodegradation occurred much faster under milder condit ions. Furthermore, NMR spectroscopic analysis proved that the biodegra dation of poly(ester-amides) involves the enzymatic hydrolysis of este r groups on the backbones of polymers into acid and hydroxyl groups. N o breakdown of amide bonds was observed under the given biotic conditi ons. (C) 1993 John Wiley & Sons, Inc.