Biodegradable polymers based on renewable resources: Polyesters composed of 1,4 : 3,6-dianhydrohexitol and aliphatic dicarboxylic acid units

Abstract

A series of polyesters was synthesized by the bulk polycondensations of the respective combinations of three stereoisomeric 1,4 : 3,6-dianhydrohexitols [1,4 : 3,6-dianhydro-D-glucitol (1), 1,4 : 3,6-dianhydro-D-mannitol (2), and 1,4 : 3,6-dianhydro-L-iditol (3)] with succinyl dichloride (4a), glutaryl dichloride (4b), adipoyl dichloride (4c), and sebacoyl dichloride (4d). Biodegradability of these polyesters was investigated by three different methods, i.e., degradation in an activated sludge, soil burial degradation, and enzymatic degradation. Although polyesters (7b–7d) based on 3 and polyester 6a derived from 2 and 4a were crystalline and scarcely biodegraded, all the other amorphous polyesters were more or less biodegradable. Biodegradability of the polyesters was found to vary significantly depending on their molecular structures. Soil burial degradation of polyesters in the soil that was treated with antibiotics, together with electron scanning microscopic observation, showed that polyesters 5b and 5c prepared from 1 and 4b or 4c were degraded by both bacteria and filamentous fungi, whereas polyester 5d from 1 and 4d was degraded primarily by filamentous fungi. © 1996 John Wiley & Sons, Inc.