Ultra‐Strong and Tough Bio‐Based Polyester Elastomer with Excellent Photothermal Shape Memory Effect and Degradation Performance

Abstract The exploitation of bio‐based materials derived from renewable resources represents a pivotal strategic approach in addressing environmental pollution and alleviating the scarcity of fossil resources. 2,5‐Furandicarboxylic acid (FDCA) is the most potential substitute for terephthalic acid. Lignin is the most abundant aromatic biomass resource. However, the preparation of high‐performance lignin/FDCA‐based bio‐polyesters remains a formidable challenge. Herein, a multifunctional lignin‐modified polyester elastomer (LFPEe) is designed using FDCA‐based polyester oligomer (PPeF) and lignin (AOH) as building blocks. The LFPEe exhibits superior mechanical properties with the optimum tensile strength, fracture strain, and elastic recovery ratio up to 58.9 MPa, 610% and 88.9%, respectively, attributing to the formation of dual cross‐linking network with nanophase separation structure. Furthermore, leveraging the inherent characteristics of lignin, the LFPEe demonstrates excellent light‐controlled shape memory and excellent UV shielding performance. This innovative work not only breaks the performance dependence of FDCA‐based polyester on high molecular weight but also highlights a novel paradigm for value‐added utilization of lignin in sustainable bio‐polyesters.