EFFECT OF CHEMICAL-STRUCTURE ON ENZYMATIC -HYDROLYSIS OF COPOLYESTERETHERS

Aliphatic copolyesterethers were synthesized from several cyclic ester s with ethylene oxide or propylene oxide by ring-opening copolymerizat ion. The biodegradability was estimated by hydrolysis using lipase (Rh izopus arrhizus) from the chemical structural point of view. The biode gradability was influenced by the polymer composition, substituted met hyl group, methylene chain length, and hydrophilicity. The biodegradab ility has the maximum at a certain composition depending on the ester content, the randomization, and crystallinity. The methyl side group i n the polymer chain suppresses the degradation. The copolymers having long methylene chains have high biodegradability because of flexibilit y of the polymer chain. Hydrophilicity promotes biodegradability. The hydrolyzed products were analyzed by H-1 NMR spectroscopy. The water-s oluble fraction mainly contained ethylene glycol, its oligomers, omega -hydroxycarboxylic acids and polyethers having a carboxylic group at i ts end. The insoluble fraction consisted of degraded copolymers.