<p>Poly(lactic acid) (PLA) is brittle with a low elongation-at-break, severely limiting its applications. To address this challenge, we synthesized a novel furan‑based copolyester, poly(ethylene furanoate‑co‑dodecylene furanoate) (PEDF), containing rigid furan rings for strength retention and long dodecylene segments for flexibility, and melt‑blended it with PLA to effectively improve ductility with high tensile strength. The results confirmed that the high molecular weight random copolymer PEDF was successfully synthesized. DSC and DMA tests indicate that the introduction of PEDF can reduce the glass transition temperature of PLA and enhance its molecular chain mobility. The tensile test shows that the elongation-at-break of PEDF is as high as 1033.6%. When the PEDF content is 30 wt%, the elongation-at-break is increased by 31.8 times compared to PLA, significantly improving the toughness of PLA. SEM revealed that the addition of PEDF changed the fracture mode of PLA from brittle fracture to ductile fracture. The XRD results indicate PEDF has clear crystallization ability, and as its content increases, the proportion of crystalline phases in the blends gradually increases. Compared with PLA, PEDF has a lower complex viscosity, while the blends contain 20 and 30 wt% PEDF exhibit higher complex viscosity due to the interaction between PLA and PEDF.</p> Graphical abstract <p></p>