Influence of carbon chain length and odd-even effect on the properties of Azelaic acid-Based aliphatic Polyesters

Abstract To adjust and optimize the structure and characteristics of biodegradable polybutylene succinate (PBS)-type polyesters, seven aliphatic polyesters with different chain lengths are being synthesized by introducing 1,9-azelaic acids. The results indicate that except for poly(propylene azelate) (PPAz), the melting points of the six polyesters progressively increase with increasing carbon chain length. The XRD analysis reveals that the odd-even effect exerts a certain influence on the diffraction peaks. Specifically, the diffraction angles of odd-odd carbon polyesters demonstrate a systematic shift compared to those of odd-even carbon polyesters. Except for PPAz and poly(hexylene azelate) (PHAz), the hydrophilicity of the polyesters decreases with increasing chain length, with poly(butylene azelate) (PBAz) being the most hydrophilic polyester. The thermal decomposition temperatures of the seven polyesters exceed 315.0 °C, indicating good thermal stability. Among them, poly(decylene azelate) (PDAz) exhibits the highest thermal decomposition temperature, reaching as high as 358.1 °C. Enzyme hydrolysis studies show that poly(pentylene azelate) (PPeAz) has the best biodegradability, with the polyester experiencing 100% weight loss after 12 h of enzymatic degradation.