Preparation and characterization of lignin-containing self-healing polyurethane elastomers with hydrogen and disulfide bonds

Inspired by biological self-healing phenomena, the preparation of lignin-containing polymer elastomers with a self-healing ability has become the focus of attention. However, the mutually exclusive conflict for the mechanical and self-healing properties of polymer elastomers makes it challenging to optimize both simultaneously. Herein, a facile strategy to prepare lignin-containing polyurethane elastomers based on hydrogen and disulfide bonds with good self-healing properties (> 93%) and tensile strength (10.77 MPa) is reported. The effect of the role of corn stover lignin as a reaction raw material and chain extender, as well as the order of introduction of disulfide bonds on the properties of polyurethane elastomers are explored. The self-healing mechanism for dynamic hydrogen and disulfide bonds in lignin-containing polyurethane elastomers is further elaborated. Due to the aromatic ring structure of lignin and its hydrogen bond interaction with the matrix, the tensile strength of the polyurethane elastomer is improved while maintaining dynamic adaptability and responsiveness. At the same time, the combination of dynamic hydrogen and disulfide bonds improves the self-healing properties of lignin-containing polyurethane elastomers. This research reports a novel high-value application of lignin, which is of great significance for making full use of biomass resources.