醇解木质素基聚氨酯薄膜的合成与性能研究

Synthesis and Properties of an Alcoholysis Lignin-based Polyurethane Film

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。

Alcoholysis lignin was isolated from the water-insoluble part of the liquefaction product of eucalyptus chips in which ethylene glycol and 1-（4-sulfobutyl）-3-methylimidazolium hydrosulfate were used as the solvent and the catalyst. The lignin was used to prepare a lignin-based polyurethane film by reacting it with polyethylene glycol （PEG 400） and hexamethylene diisocyanate （HDI）. The results showed that when the lignin content was 20% and the isocyanate index was 1.9, the maximum tensile strength of lignin-based polyurethane film was 11.77 MPa and the elongation at break was 362.98%. The addition of lignin could improve the thermal stability of polyurethane. The glass transition temperature （Tg） increased with the increase of lignin content. When the lignin content is 20%, the increase of the isocyanate index has little effect on the thermal stability of the lignin-based polyurethane film, and the Ts increases with the increase of the isocyanate index gradually.