Mechanically Robust, Reprocessable, and Light-Controlled Healable Solvent-Free Lignin-Containing Polyurethane Elastomers Based on Dynamic Phenol-Carbamate Network

In this study, we introduce an innovative one-step, solvent-free approach for preparing lignin-containing polyurethane elastomers (LPUes) with nanomicro phase-separated structure and dynamic dual-cross-linking networks comprising both phenol-carbamate bonds (PCBs) and hydrogen bonds. This distinctive structural design imparted exceptional mechanical properties to the LPUes. The sample containing 22.9 wt % phenolized lignin exhibited tensile strength of 44.6 MPa, elongation at break of 714.6%, and toughness of 148.0 MJ/m3. The abundance of dynamic PCBs also conferred remarkable reprocessing capabilities, with these LPUes retaining over 98% for tensile strength and 94.4% for toughness after two hot-pressing cycles. Moreover, the incorporation of lignin endowed the LPUes with photothermal properties, facilitating efficient light-controlled self-healing and shape-memory functionalities. This work offers an innovative pathway to harmonize the mechanical properties and thermal adaptability in the development of sustainable and high-performance LPUes, thereby opening their avenues for diverse potential applications.