木质素脱甲基化改性及其应用的研究(论文10000字)
摘 要
随着石油、煤炭等资源不断被开采消耗，随着能源危机问题的日益严峻，开发化石能源替代品已刻不容缓。木质素作为天然高分子产物，在自然界中储量巨大，具有绿色环保、可再生的优点。因此，如果将工业生产过程副产物木质素转化为化工原料进行再生利用，不仅能够起到节约能源的作用，还可以避免工业废水排放带来的环境污染等一系列问题。然而，由于木质素属于复杂的芳香化合物，结构特点复杂无定形，本身反应活性不高，高值利用率低，限制了其工业化应用。因此，从木质素的结构和性质入手，对其进行改性加工，将对工业生产的促进起到十分重要的作用。改性后的木质素不仅能提高利用率，还能实现木质素在高分子材料领域对石油原料的有效替代，降低对石油等不可再生资源的依赖。如何对其进行改性并高效利用，现已成为各大科研机构的重点研究课题。本文首先筛选不同的催化剂研究其对木质素改性的影响，并对改性后的木质素进行红外、核磁以及GPC表征；然后，使用改性后的木质素代替苯酚制备酚醛树脂胶，并对其性能进行表征，研究其与酚醛树脂胶黏剂在性能指标上的区别。
关键词：木质素改性；脱甲基化；结构表征；树脂胶黏剂
Study on Demethylation Modification of Lignin and Its Application
ABSTRACT
With the continuous consumption of oil, coal, and other resources, as the energy crisis becomes more and more severe, the development of fossil energy alternatives has become an urgent task. As a natural polymer product, lignin has huge reserves in the natural world, and it has the advantages of being green and recyclable. Therefore, if the lignin, a by-product of the industrial production process, is converted into chemical raw materials for recycling, it will not only be able to save energy but also avoid environmental pollution caused by industrial wastewater discharge. However, because lignin belongs to complex aromatic compounds, its structural characteristics are complex and amorphous, its reactivity is not high, and its high value is low, which limits its industrial application. Therefore, starting from the structure and properties of lignin and modifying it will play a very important role in the promotion of industrial production. The modified lignin can not only improve the utilization rate, but also can effectively substitute lignin for petroleum raw materials in the field of polymer materials and reduce dependence on non-renewable resources such as petroleum. How to modify it and use it effectively has become a key research topic for major scientific research institutions. This article first screens different catalysts to study its effect on modification of lignin, and performs FT-IR, 1HNMR and GPC characterization on the modified lignin. Then, the modified lignin is used instead of phenol to make phenolic resin. Its performance was characterized and the difference between its performance and phenolic resin adhesive was studied.
Key words：Lignin modification; Demethylation; Structural characterization; Resin adhesives
目 录
1 绪论………………………………………………………………………………………1
1.1 木质素的分类……………………………………………………………………………1
1.2 木质素的物理性质………………………………………………………………………………..1
1.2.1 颜色……………………………………..…………………………………………………1
1.2.2 溶解度……………………………………..…………………………………………………2
1.2.3 相对分子质量……………………………..…………………………………………………2
1.2.4 相对密度…………………………………..………………………………………..………2
1.3 木质素的化学性质……………………………………………………………………...…………2
1.3.1 木质素的结构…………………………...…………………………………………………3
1.3.2 主要官能团..…………………………...…………………………………………………3
1.4 木质素的提取工艺……………………………………………………………………...…………4
1.4.1 传统提取法………………………...……...…………………………………………………4
1.4.2 有机溶剂提取法..……………………..…...………………………………………………5
1.5 木质素的纯化..…………………………………...………………………………………………5
2 木质素的化学改性研究…………………………………………………………………………………6
2.1 木质素化学改性的概述….……………………………………………………………………7
2.2 木质素化学改性的方法及特点………………………………………………………………7
2.2.1 酚化改性法…………………………………………………………………7
2.2.2 催化还原法…………………………………………………………………7
3 木质素脱甲基化法改性及结构表征……………………………….……………………………………8
3.1 实验原理…………………….……………………………………………………………………8
3.2 实验原料与试剂………..…………………………………………………………………………8
3.3 实验设备与仪器…………….……………………………………………………………………8
3.4 试验方法………………..…………………………………………………………………………8
3.2.1 不同金属盐催化剂对木质素反应活性的影响……...……………………………………8
3.2.2 木质素红外光谱分析………………………………...……………………………………9
3.2.3 木质素的核磁共振分析……………………………...……...……………………………11
3.2.4 木质素的凝胶色谱分析……………………………...…………………………………12
3.5 本章小结……………………………………………………………………………………….12
4 木质素改性酚醛树脂胶黏剂的制备……………………………………。………………………….13
4.1 实验原料……………………………………………………………………………………….13
4.2 反应装置……………………………………………………………………………………….13
4.3 制备方法……………………………………………………………………………………….13
4.4 苯酚制备酚醛树脂胶的表征…………………………………….…………………………….14
4.4.1 固含量…………………………………………………...……………………………….14
4.4.2 粘度………...…………………………………………………………………………….14
4.4.3 pH值……...…………………………………………………………………………….14
4.4.4 游离甲醛含量………………………………………………………………………….15
4.5 木质素酚醛树脂胶的表征…………………………………………………………………….15
4.6 改性木质素与苯酚合成酚醛树脂胶的性能对比…………………………………………….15
结论…………………………………………………………………………………………………………17
致谢…………………………………………………………………………………………………………18
参考文献…………………………………………………….……………………………………………19 |
