A one-step and solvent-free strategy for high lignin-containing polyurethane elastomers with excellent mechanical and...

Lignin, a renewable and biodegradable polymer, offers a promising alternative to petroleum-based polyols for polyurethane elastomer synthesis. However, its complex structure poses challenges, such as poor dispersibility and reactivity. This study introduces a novel one-step and solvent-free method for synthesizing lignin-containing polyurethane elastomers (SF-LPUes-ONE) with a high lignin substitution rate of at least 30 wt%. By directly incorporating a dispersion of ethanol-extracted lignin and long-chain polyols into the reaction with isocyanates, we successfully prepared SF-LPUes-ONE with remarkable mechanical properties. The tensile strength, elongation at break, and toughness of the resulting sample reached 42.3 MPa, 584.7 %, and 110.0 MJ/m³, respectively. In addition, the phenolic hydroxyl groups in lignin endowed SF-LPUes-ONE with excellent anti-aging resistance, ensuring sustained high performance under demanding conditions. Furthermore, the dynamic hydrogen bonding and chemical cross-linking dual-network endowed SF-LPUes-ONE with exceptional shape memory capabilities, achieving shape fixation and recovery rates exceeding 99 % after 3 cycles. This work demonstrates a green and efficient approach to high-performance lignin-based polyurethane elastomers, showcasing their potential for broad industrial applications.