本文選題：聚苯并咪唑 + 二氮芴�。� 參考：《蘭州大學》2017年碩士論文

【摘要】：芳香型聚苯并咪唑(PBI)具有良好的熱化學穩(wěn)定性和力學性能,廣泛應用于耐火纖維,防腐涂層,航空航天及燃料電池等領域。在PBI結構中,弱堿性咪唑環(huán)可吸附磷酸,從而具備質(zhì)子傳導能力,因此磷酸摻雜聚苯并咪唑薄膜被看作是最具潛力的高溫質(zhì)子交換膜。但是,傳統(tǒng)聚苯并咪唑因其剛性結構而導致較差的溶解加工性能,極大地限制了其實際應用。因此,研究制備新型易溶可加工聚苯并咪唑具有重要的實際意義。本文從分子結構設計出發(fā),通過合成四胺、二酸單體,成功將吡啶,醚鍵,大體積的苯側基和扭曲、非共面的二氮芴Cardo結構引入聚苯并咪唑主鏈,得到了一系列機械性能、熱化學穩(wěn)定性良好的易溶聚苯并咪唑,通過磷酸摻雜,所得質(zhì)子交換膜具有良好的質(zhì)子傳導率和穩(wěn)定性。主要研究內(nèi)容如下:1、制備了含扭曲非共面結構的Cardo型芳香二酸單體:9,9-雙(4-羧苯基)-4,5-二氮芴。并與2,6-雙(3,4-二氨基苯基)-4-苯基吡啶通過程序升溫法制備了易溶聚苯并咪唑聚合物。對比兩種不同結構的四胺單體3,3',4,4'-聯(lián)苯四胺與2,6-雙(3,4-二氨基苯基)-4-苯基吡啶對聚合物性能的影響,闡明非共面結構對聚苯并咪唑溶解性的影響。結果表明,該新型聚苯并咪唑在常溫下在多種常用極性非質(zhì)子有機溶劑(如DMF、DMAc、DMSO、NMP)中有優(yōu)異的溶解性。而且芳雜環(huán)的引入并沒有減弱該聚合物的熱、化學穩(wěn)定性,制備的兩種聚合物薄膜5%熱損失溫度為318 oC,10%熱損失溫度為540 oC。另外,在5 mol/L的磷酸溶液中,吡啶四胺結構聚苯并咪唑(PyTAB-PBI)磷酸摻雜水平達到8.12,高于聯(lián)苯四胺結構聚苯并咪唑(TAB-PBI)的6.40,其質(zhì)子傳導率也由0.046 S cm-1提高到0.068 S cm-1。2、通過分子結構設計,制備了含醚及二氮芴Cardo型芳香二酸單體:9,9-雙(4-羧苯氧基)-4,5-二氮芴,以此將柔性醚鍵引入聚苯并咪唑分子主鏈,改善分子鏈的柔性,使分子鏈容易翻轉,增加分子鏈間的距離,從而減小分子鏈間的相互作用力,改善其溶解性能。醚鍵的存在導致該聚合物熱穩(wěn)定性有略微降低,5%熱損失溫度為204 oC。另外,聚苯并咪唑薄膜通過不同濃度(5、7、9、11 mol/L)的磷酸摻雜測試表明,在9 mol/L的磷酸溶液中,該膜磷酸摻雜水平達到12.37,在干燥狀態(tài),180 oC時質(zhì)子傳導率為0.072 S cm-1。3、通過分子結構設計,合成側鏈含有羥基的四胺單體:2,6-雙(3,4-二氨基苯基)-4-羥苯基吡啶。在聚苯并咪唑側鏈引入羥基,與主鏈的咪唑環(huán)形成離子交聯(lián)結構。分子間的氫鍵存在使膜的溶解性能有所降低,溶解性測試表明在羥基含量高于60%時,聚合物在加熱至100 oC后才可以完全溶解。交聯(lián)結構增強了膜的尺寸穩(wěn)定性,側鏈含羥基的PBI膜比不含羥基的PBI膜溶脹率降低30%左右。聚合物側鏈的羥基易磷酸分子之間形成橋聯(lián)結構,使一部分磷酸分子固定在分子鏈上,磷酸摻雜水平較不含羥基PBI膜略微提高。
[Abstract]:Aromatic polybenzimidazole (PBI) has good thermochemical stability and mechanical properties. It is widely used in refractory fibers, anticorrosive coatings, aerospace and fuel cells. In PBI structure, phosphoric acid can be adsorbed by weak basic imidazole ring, which has the proton conduction ability. Therefore, phosphoric acid doped polybenzimidazole film is considered as the most potential high temperature proton exchange membrane. However, due to its rigid structure, traditional polybenzimidazole has poor solubility and processing performance, which greatly limits its practical application. Therefore, it is of great practical significance to study the preparation of new soluble and processable polybenzimidazole. Based on the molecular structure design, a series of mechanical properties of polybenzimidazole were obtained by synthesizing tetraamine, diacid monomer, pyridine, ether bond, large volume benzyl side group and twisted, non-coplanar fluorene Cardo structure into the main chain of polybenzimidazole. The readily soluble polybenzimidazole with good thermochemical stability was prepared by phosphoric acid doping and the proton exchange membrane had good proton conductivity and stability. The main contents of this study are as follows: 1. Cardo aromatic diacid monomers with distorted noncoplanar structure: 1. 9- (4-carboxyphenyl) -4- (4-) -5-diazofluorene was prepared. The soluble poly (benzimidazole) polymer was prepared by temperature-programmed method with 2o 6 bis (3 O 4 diaminophenyl) -4 phenyl pyridine. The effects of two kinds of tetraamine monomers, 3- (3-)-(3-)-(4-diaminophenyl) -4-phenyl-pyridine, on the solubility of poly (benzimidazole) were compared with those of 2o _ 6bis (3o _ 4-diaminophenyl) -4-phenylpyridine. The effect of non-coplanar structure on the solubility of polybenzimidazole was discussed. The results show that the novel polybenzimidazole has excellent solubility in a variety of commonly used polarity non-proton organic solvents such as DMFX DMAC DMSON NMP at room temperature. Moreover, the introduction of aromatic heterocycles did not weaken the thermal and chemical stability of the polymer. The 5% heat loss temperature of the two polymer films was 318 OC 10% and the heat loss temperature was 540 OC. In addition, in 5 mol / L phosphoric acid solution, the phosphoric acid doping level of PyTAB-PBI was 8.12, which was higher than that of TAB-PBI (6.40), and the proton conductivity was increased from 0.046 S cm-1 to 0.068 S cm-1.2. In this paper, the ether and fluorene Cardo aromatic diacid monomer: 9 ~ 9- bis (4-carboxyphenoxy) -4o _ 5- diazofluorene was prepared. The flexible ether bond was introduced into the main molecular chain of poly (benzimidazole), which improved the flexibility of the molecular chain, made the molecular chain easy to flip and increased the distance between the molecular chains. Therefore, the interaction force between molecular chains is reduced and the solubility is improved. The presence of ether bond leads to a slight decrease in the thermal stability of the polymer by 5% to 204 OC. In addition, the phosphoric acid doping of polybenzimidazole thin films at different concentrations (5 ~ 7 ~ 9 ~ 9 ~ 11 mol / L) shows that in 9 mol / L phosphoric acid solution, the phosphoric acid doping level of the film is 12.37, and the proton conductivity is 0.072 S ~ (cm ~ (-1) at a dry state of 180oC, which is designed by molecular structure. In this paper, a tetraamine monomer with hydroxyl groups in the side chain was synthesized. The hydroxyl group was introduced into the side chain of polybenzimidazole and the ionic crosslinking structure was formed with the imidazole ring of the main chain. The solubility of the membrane was decreased by the existence of hydrogen bond between molecules. The solubility test showed that when the hydroxyl content was higher than 60 鈩，

本文編號：2079202