Lignin, as a green and environmentally sustainable natural material, is indispensable to be reasonably developed and utilized. Herein, lignin macromolecules are used as raw materials of polyhydroxyl structure to synthesize polyurethane macromolecules. It is found that the optimal mass ratio of lignin to isocyanate group in the synthesis of polyurethane is 95/5. The lignin-based polyurethane putted the lignin as a fulcrum to form a hydrogen bond with the polyurethane macromolecular chain to form a hydrogen bond network structure, so that its elastic recovery rate attains 94.7%. Meanwhile, its tensile strength and breaking elongation rate reach 16.2 MPa and 1049.5% respectively. Furthermore, the lignin-based polyurethane synthesized in this work still maintain excellent mechanical properties after thermal reprocessing. Moreover, the lignin-based polyurethanes prepared by this approach also possess excellent transparency and UV resistance, and the average ultraviolet protection factor (UPF)value of the lignin-based polyurethane hot-pressed fabrics obtained by hot pressing is greater than 50. This work provides an innovative and sustainable strategy for the further application of lignin, a pure natural material, as a bio-based multifunctional additive to packaging, textiles, automotive trim and other fields.

木质素作为一种绿色环保的天然材料，需要合理开发利用。本发明以木质素大分子为多羟基结构的原料合成聚氨酯大分子。发现合成聚氨酯时木质素与异氰酸酯基团的最佳质量比为95/5。木质素基聚氨酯以木质素为支点，与聚氨酯大分子链形成氢键，形成氢键网络结构，其弹性回复率达到94.7%。同时，其拉伸强度和断裂伸长率分别达到16.2 MPa和1049.5%。此外，这项工作中合成的木质素基聚氨酯在热再加工后仍保持优异的机械性能。而且，