Effects of alkylene spacer length of 2-pyrone-4,6-dicarboxylic acid polyesters on biodegradability and metal adhesive properties

Abstract 2-Pyrone-4,6-dicarboxylic acid (PDC) is a lignin-derived biometabolic intermediate that can be produced on a large scale by using transforming bacteria and can be directly polymerized by polycondensation with diols to produce biomass polyesters. In the present study, a variety of PDC-based polyesters were successfully synthesized by direct polymerization between PDC and diols with different alkyl chain lengths. The thermal, crystalline, and mechanical properties of a series of PDC polyesters were fully characterized. The biodegradability of the PDC polyesters was investigated by biodegradation tests in a confined simulated environment using pond water. There was a clear correlation between the biodegradation rate, alkylene spacer length, and polymer hydrophilicity. In addition, the PDC polyesters exhibited excellent adhesive properties to various metals, and their adhesive properties gradually decreased with a decrease in the PDC content in the polymers. The excellent adhesion to an aluminum plate with the lap-shear strength of up to 15.26 MPa was demonstrated and this value is comparable to those of the-state-of-the-art commercial quick-drying metal adhesives.