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以醇解木质素、聚乙二醇和六亚甲基二异氰酸酯(HDI)为原料合成聚氨酯薄膜,探讨了异氰酸酯指数以及木质素添加量对木质素基聚氨酯薄膜热性能和机械性能的影响。结果表明:木质素添加量为20%,异氰酸酯指数为1.9时木质素基聚氨酯膜的力学性能指标达到最佳,其拉伸强度为11.77 MPa,断裂伸长率为362.98%。木质素的添加可以改善聚氨酯热稳定性。木质素基聚氨酯薄膜的玻璃化转变温度(T_g)随木质素添加量的增大有明显的提高。木质素的添加量为20%时,异氰酸酯指数的增大对木质素聚氨酯薄膜的热稳定性影响不大,T_g随异氰酸酯指数的增大逐渐增大。
Polyurethane films were synthesized from alcohol - lignin, polyethylene glycol and hexamethylene diisocyanate (HDI). The effects of isocyanate index and lignin content on the thermal and mechanical properties of lignin - based polyurethane films were also discussed. The results showed that the mechanical properties of the lignin - based polyurethane films reached the best when the lignin content was 20% and the isocyanate index was 1.9. The tensile strength was 11.77 MPa and the elongation at break was 362.98%. The addition of lignin can improve the thermal stability of polyurethane. The glass transition temperature (T_g) of lignin-based polyurethane film increased obviously with the increase of lignin content. When the content of lignin is 20%, the increase of isocyanate index has little effect on the thermal stability of lignin polyurethane film, T_g increases with the increase of isocyanate index.