Enhancing Integrated Performance of Fully Biobased Polyester Elastomers via Crystallizable Aliphatic Soft Segments and Furanic Rigid Segments

To address the environmental persistence of conventional petroleum-based elastomers, a sustainable strategy was developed for fabricating high-performance, fully biobased polyester elastomers. A rigid-segment prepolymer, poly(butylene furandicarboxylate), was synthesized via esterification of dimethyl 2,5-furandicarboxylate with 1,4-butanediol (BDO). In parallel, a flexible prepolymer (PBAD) was prepared from 1,2-propanediol (PDO), BDO, succinic acid (SA), and 1,10-decanedioic acid. Polycondensation of these prepolymers yielded a series of P(BF-PBAD) copolyesters with tunable properties. The crystallization behavior was found to be dominated by the hard segments, while the soft segments also contributed to crystallinity. Increasing PBAD content disrupted hard segment crystallization, yet the materials retained high thermal stability, exhibiting initial degradation temperatures around 330 °C. Notably, these elastomers achieved an outstanding balance between strength and extensibility, with tensile strength of 13–50 MPa and elongation at break of 550–1200%. All samples displayed water contact angles below 90°, confirming their hydrophilic nature. Degradation studies revealed excellent stability in PBS buffer with negligible mass loss, consistent with slow neutral hydrolysis and limited dissolution/diffusion of degradation products, whereas markedly accelerated degradation occurred in alkaline media due to OH–-promoted ester bond cleavage and enhanced leaching of oligomers; in both environments, higher PBAD content further increased the overall degradation rate by promoting medium accessibility and reducing crystallinity. This work successfully synthesized a sustainable biobased polyester elastomer by introducing crystallizable soft segments and systematically varying the contents of soft and hard segments. The resulting elastomer exhibits balanced strength and toughness, excellent thermal stability, hydrophilicity, and controllable degradability, as well as a low melting point that is conducive to processing, demonstrating outstanding integrated performance.