Fusible, Elastic, and Biodegradable Polyesters of 2-Pyrone-4,6-Dicarboxylic Acid (PDC)

Abstract

2-Pyrone-4,6-dicarboxylic acid (PDC), a chemically stable metabolic intermediate of lignin, 1,4-butanediol, and succinic anhydride were polymerized in the presence of an appropriate catalyst, such as Sb2O3, TiO(acac)2, and CH3SO3H, to afford the corresponding polyesters. The molecular weight (Mn) of the polyesters exceeded 10,000, but they were soluble in the common organic solvents when the PDC feed ratio was <10 mol %. Furthermore, the polyesters showed well-defined melting points ranging from 82 to 107 °C and, consequently, the fusibility was realized for the first time for the PDC polymers. Films of these PDC polyesters lacked sufficient mechanical strength, but blended films with poly(L-lactic acid) were found to improve the elastic features. The degradation behaviors of the PDC polyesters were investigated by the biodegradability test or the accelerated hydrolysis tests. Comparison between the obtained PDC polyester and poly(butylene succinate) revealed a remarkable increase in the biodegradability by copolymerization with PDC.