BIODEGRADABILITY OF POLYESTERS HAVING TETRAHYDROPYRAN RINGS IN THEIR BACKBONES

Biodegradability of several homo- and copolyesters, containing tetrahy dropyran rings in their backbones with or without pendant groups, was investigated by degradation tests, both in soil and in an activated sl udge. These polyesters were hydrolytically degraded to lower molecular weight compounds, and eventually to hydroxytetrahydropyran carboxylic acids, at different rates, depending on their molecular structure. Qu antitative determination of carbon dioxide, generated during the treat ment with the activated sludge, showed that the hydrolysates from poly esters 2 and 10, without pendant alkoxycarbonyl groups, were cataboliz ed by microorganisms. It was concluded from these results that at leas t the polyesters without pendant groups were biodegradable, and that p olyester 10, consisting of 2,6-linked tetrahydropyran rinp, underwent biodegradation more readily than polyester 2, consisting of 2,5-linked tetrahydropyran rings. (C) 1994 John Wiley & Sons, Inc.