Architecture of biodegradable copolyesters containing aromatic constituents

Aliphatic/aromatic copolyesters, especially those synthesized from butanediol, adipic acid and terephthalic acid, have been shown to represent biodegradable plastics of high commercial interest. Within a range of approx. 30-55 mol% terephthalic acid in the acid components such copolymers are an acceptable compromise between use properties and degradation rate. The behaviour of aromatic intermediates has been examined by use of specially synthesized aromatic model oligomers. Oligomers with a degree of polymerization of one and two are rapidly degraded by microorganisms; for longer oligomers, only a chemical hydrolysis is postulated at higher temperatures. By means of enzymatic hydrolysis of monomeric model esters with a lipase it was shown that the rigidity, especially of the diacid component, influences the accessibility of the ester bonds to the action of the lipase. (C) 1998 Elsevier Science Limited. All rights reserved.