High-Performance Lignin-Based Polyurethane Elastomer via Solvent Fractionation

The poor compatibility and low degree of substitution of lignin severely limit its application as a polyol substitute in polyurethane elastomers. Herein, by regulating the molecular weight of lignin, high-content and uniform bonding of lignin in polyurethane (PU) has been achieved. Even at a substitution degree of 15%, lignin can still be fully integrated into the macromolecular chains of PU, resulting in a 27% increase in tensile strength and a 124% increase in elongation at break of the elastomer, respectively. Furthermore, a remarkable enhancement of over 165% in the tensile strength of the elastomer has been realized through adjusting the molecular weight of lignin. And through life cycle assessment, the importance of using lignin as a substitute for polyols has been confirmed. Notably, the thermal stability and surface hydrophobicity of the elastomer have also been significantly improved, and it can be combined with MXene to fabricate composite devices with sensitive strain responsiveness. This promising advancement is expected to promote the green and sustainable development of PU and its application in multifunctional wearable devices.