多孔芳香骨架膜材料的合成及性质研究

发布时间：2018-01-15 21:23

本文关键词：多孔芳香骨架膜材料的合成及性质研究　出处：《吉林大学》2015年硕士论文　论文类型：学位论文

【摘要】：多孔材料由于具有高的比表面积，孔道结构多样性的特点引起了材料领域的科学家们广泛关注，尤其在气体分离与存储领域，多孔材料的应用最为广泛。目前，合成的多孔材料主要为颗粒状的，并且需要苛刻的条件进行气体的存储与分离，因此，将其制备成膜材料将更具有应用价值。本论文设计合成了自身具有孔道结构的多孔芳香骨架化合物（PAF）膜材料并研究其在CO2/N2气体分离方面的性质。多孔芳香骨架化合物（PAFs）是一种刚性芳香结构基元连接而成的有机多孔材料，，具有骨架密度低，稳定性高的特点，其本身的孔结构及其官能团的可加工性被认为是最合适的成膜材料。本论文第二部分中我们首先通过三氟甲磺酸（CF3SO3H）催化含有氰基的芳香单体自身聚合制备出自支撑的柔性膜（PAF-57）。通过FTIR和NMR表征，证实了氰基（-CN）发生了聚合反应生成三嗪环结构，SEM显示膜表面光滑连续，无明显裂缝缺陷。气体分离实验发现该膜有反常的膜分离效果。于是我们又进一步做了气体透量随压力变化的实验：随着进气压力的增大，CO2的透量几乎无明显变化，与此同时N2的透量随着压力增大而增大。因此，理想的气体分离系数逐渐增大。实验测得将N2/CO2（体积比为1:1）的混合气体通过膜时，压力从0.1MPa到0.5MPa时，N2/CO2的分离系数为1.7~4.5，N2的透量从2.3×10-7mol m-2s-1Pa-1增大到7.7×10-7mol m-2s-1Pa-1。在与传统的膜选择性与透量的权衡关系中，PAF-57膜表现出反常的膜分离效果。在较高渗透压力下，该膜将具有更加优异的膜分离效果。本文的第三部分我们用含有烷烃链（-CH3）的有机单体在CF3SO3H为催化剂的条件下，制备出枝状的多孔芳香骨架膜材料（PAF-58）。同样，通过FTIR和NMR等基础表征，证明制备出的PAF-58膜符合设计预期。在273K，1bar条件下，PAF-58膜表现出对CO2很强的吸附能力，CO2/N2吸附分离比为119.3。此归因于膜骨架中含大量碱性给电子基团N，易于与CO2之间发生相互作用，同时烷烃链的引入具有一定的位阻效应，阻碍了N2与膜之间的相互作用，两种作用同时存在，增大了膜的选择性，提高PAF-58膜的气体分离能力。膜分离实验也证实了上面的结果，在室温下，将CO2/N2（体积比1：1）混合气体通过膜后，该膜具有很好的膜分离效果，CO2的透量约为5.2×10-8mol m-2s-1Pa-1。长时间进行膜分离实验时，CO2的透量几乎无变化，说明PAF-58膜具有良好的稳定性。
[Abstract]:Because of its high specific surface area and diversity of pore structure, porous materials have attracted wide attention of scientists in the field of materials, especially in the field of gas separation and storage, porous materials are most widely used. At present, porous materials are widely used in the field of gas separation and storage. The synthesized porous materials are mainly granular and require harsh conditions for gas storage and separation. In this thesis, we designed and synthesized the porous aromatic skeleton compound (PAF) with its own pore structure. Membrane materials and their properties in CO2/N2 gas separation were studied. Porous aromatic matrix compound (PAFs) is an organic porous material with rigid aromatic structure elements, which has the characteristics of low skeleton density and high stability. Its pore structure and the processability of its functional groups are considered to be the most suitable film-forming materials. In the second part of this thesis, we first adopted CF3SO3H- (trifluoromethyl sulfonic acid). The self-polymerization of aromatic monomers containing cyanide was used to prepare the self-supporting flexible membrane PAF-57. It was characterized by FTIR and NMR. It is proved that the surface of the film is smooth and continuous due to the polymerization of cyanobutadiene (CNN) and the formation of triazine ring structure (SEM). There is no obvious crack defect. Gas separation experiment found that the membrane has abnormal membrane separation effect. So we further do the gas permeability with the pressure change experiment: with the increase of inlet gas pressure. The permeability of CO2 hardly changed, while the permeability of N2 increased with the increase of pressure. The ideal gas separation coefficient increases gradually. The experimental results show that when the mixture of N _ 2 / CO _ 2 (volume ratio is 1: 1) passes through the membrane, the pressure ranges from 0.1 MPA to 0.5 MPA. The separation coefficient of N _ 2 / CO _ 2 is 1.7% 4.5. The penetration of N2 increased from 2.3 脳 10-7mol m-2s-1Pa-1 to 7.7 脳 10-7mol. M-2s-1Pa-1. In the tradeoff between traditional membrane selectivity and permeability. PAF-57 membrane shows abnormal membrane separation effect, and it will have better membrane separation effect at higher osmotic pressure. In the third part of this paper, we use organic monomers containing alkane chain-CH3 under the condition of CF3SO3H as catalyst. The branched porous aromatic framework membrane (PAF-58) was prepared. Similarly, FTIR and NMR were used to characterize the prepared PAF-58 membrane. The results showed that the prepared PAF-58 membrane was in line with the design expectation at 273K. The adsorption and separation ratio of CO _ 2 / N _ 2 on PAF-58 membrane was 119.3 under the condition of 1 bar, which was attributed to the existence of a large number of basic electron donor groups N in the membrane skeleton. It is easy to interact with CO2, and the introduction of alkane chain has a certain steric resistance effect, which hinders the interaction between N2 and membrane. The two kinds of interaction exist at the same time, and increase the selectivity of the membrane. The experiment of membrane separation also confirmed the above results. At room temperature, the mixture of CO _ 2 / N _ 2 (volume ratio 1: 1) was passed through the membrane. The membrane has a good membrane separation effect. The permeability of CO _ 2 is about 5.2 脳 10 ~ (-8) mol m ~ (-2) s-1Pa-1.When the membrane separation experiment is carried out for a long time, there is almost no change in the permeability of CO _ 2. It shows that PAF-58 film has good stability.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O625;TB383.2

【参考文献】