高反应性木质素的高效提取及其制备生物聚氨酯泡沫

为了解决木质素参与聚氨酯泡沫反应存在结构复杂、纯度低、分子质量大、反应性较低等问题,本研究以天然竹粉为原料,利用氯化胆碱(ChCl)和草酸六水合物(Oad)制备低共熔溶剂(DES)作为提取溶剂,结合超声波辅助技术提取高活性酚羟基木质素,并将其作为反应单体替代部分石化多元醇,通过全水发泡法制备木质素聚氨酯泡沫(LPUF),并对其化学结构、微观形貌和力学性能进行分析。研究结果表明:基于DES超声波辅助处理未破坏木质素的基本结构,LPUF成功制备;较优的提取工艺条件为提取温度80℃、超声波作用时间0.5 h、超声波功率70 W,此条件下木质素含酚羟基8.8%、提取率高达87.8%。当木质素与聚乙二醇200(PEG-200),聚乙二醇400(PEG-400)和六亚甲基二异氰酸酯(HDI)的质量比为1∶84∶23∶155,所制备的木质素聚氨酯泡沫LPUF-2,平均孔径261.66μm,弹性模量3 MPa,经1000次压缩循环,LPUF-2最大应力为22.26 kPa,仍能保持初始应力的84%以上,显示出优异的力学性能及稳定性。

溶剂型木质素在聚氨酯改性材料中的应用

溶剂型木质素(organosolv lignin)与传统木质素盐类相比具有反应活性基团含量高、容易直接与异氰酸酯反应形成聚氨酯。介绍溶剂型木质素的制备、结构特点以及在木质素改性聚氨酯泡沫材料领域的应用,实验结果表明,溶剂型木质素可以替代部分多元醇,制备聚氨酯泡沫材料。木质素改性聚氨酯泡沫材料保温性能良好,又能降低生产成本,有推广应用的前景。

Performance characterization, of rigid polyurethane foam with refined alkali lignin and modified alkali lignin

The two kinds of rigid polyurethane （PU） foams were prepared with respectively adding the refined alkali lignin and alkali lignin modified by 3-chloro-1,2-epoxypropane to be instead of 15% of the polyether glycol in weight. The indexes of mechanical performance, apparent density, thermal stability and aging resistance were separately tested for the prepared PU foams. The results show that the mechanical property, thermal insulation and thermal stability for PU foam with modified alkali lignin are excellent among two kinds of PU foams and control samples. The additions of the refined alkali lignin and modified alkali lignin to PU foam have little effect on the natural aging or heat aging resistance except for decreasing hot alkali resistance apparently. Additionally, the thermal conductivity of modified alkali lignin PU foam is lowest among two kinds of PU foams and control samples. The alkali lignin PU foam modified by 3-chloro-1,2-epoxypropane could be applied in the heat preservation field.