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Polybenzimidazole with sulfonated side chain and preparation method thereof

A polybenzimidazole and benzimidazole technology, which is applied in the parts, electrical components, circuits and other directions of fuel cells, can solve the problems of low proton conductivity, complex reaction process, and difficulty in quantitative execution.

Active Publication Date: 2013-05-01
UNIV OF SCI & TECH OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Among them, the use of strongly basic metal hydrides requires the reaction system to be strictly anhydrous, and the reaction process is complicated and difficult to carry out quantitatively.
More importantly, the number of sulfonic acid groups in the side chain sulfonated polybenzimidazoles synthesized by these N-alkylation modification methods is always smaller than that of benzimidazole groups (theoretically, most The acidic sulfonic acid group will be neutralized by the basic benzimidazole group, resulting in a greatly reduced number of protons that can be dissociated) and it is difficult to achieve that the number of sulfonic acid groups is greater than the number of benzimidazole groups, which leads to A low proton conductivity (typically below 10 -3 S / cm level) but cannot meet the requirements of proton exchange membrane fuel cells

Method used

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  • Polybenzimidazole with sulfonated side chain and preparation method thereof
  • Polybenzimidazole with sulfonated side chain and preparation method thereof
  • Polybenzimidazole with sulfonated side chain and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] Embodiment 1: the synthesis of dibenzimidazole monomer

[0044] Take the synthesis of a dibenzimidazole monomer as an example: 1.0 moles of 3,3'-benzidine (purity 97%), 2.0 moles of 4-phenoxybenzoyl chloride (purity 97%) and 0.5 liter of N-methylpyrrolidone into a 1.0 liter reaction flask with nitrogen gas, mechanically stirred at 25°C for 12 hours, then heated to 180°C for 4 hours, cooled and poured into dilute NaOH aqueous solution, filtered, and water and ethanol repeated washing, vacuum drying to obtain dibenzimidazole monomer (yield 90%) can be directly used in the next step of polymerization. In the infrared spectrum at 1625cm -1 (C=N, moderately strong) the characteristic absorption peak of imidazole appears, and the reaction formula is as follows:

[0045]

Embodiment 2

[0047] In turn, 1.00 moles of 4,4'-diphenyl ether dicarboxylic acid, 0.99 moles of the dibenzimidazole monomer synthesized in Example 1, and 0.01 moles of 2,2'-bis(3-sulfonated propoxy)bis Disodium benzene, and 4 liters of Eaton's reagent were added to a nitrogen-filled reaction bottle, stirred and reacted at 80°C for 48 hours, and the reaction solution was poured into a large amount of deionized water while it was hot to obtain a polymer precipitate, filtered and washed repeatedly with deionized water until the filtrate is neutral, the obtained polymer is soaked in 0.1mol / L dilute NaOH solution at room temperature for 24 hours, then washed repeatedly with deionized water until the washing solution is neutral, and vacuum dried to obtain Na + Polymers with side chains containing sulfonic acid groups in the form of polymers. In the infrared spectrum at 1646cm -1 The characteristic absorption peak of carbonyl group appears on the left and right and the absorption peak of carboxy...

Embodiment 3

[0052] 1.00 mole of 4,4'-diphenyl ether dicarboxylic acid, 0.50 mole of dibenzimidazole monomer synthesized in Example 1, 0.50 mole of 2,2'-bis(3-sulfonated propoxy)bis Disodium benzene, prepared according to the method of Example 2, and 4 liters of Eaton's reagent were added to a nitrogen-filled reaction bottle, stirred and reacted at 100°C for 24 hours, and the reaction solution was poured into a large amount of deionized water while it was hot to obtain a polymer precipitate, filtered And wash repeatedly with deionized water until the filtrate is neutral, soak the obtained polymer with 0.1mol / L dilute NaOH solution at room temperature for 24 hours, then wash repeatedly with deionized water until the washing liquid is neutral, and vacuum dry to obtain Na + Polymers with side chains containing sulfonic acid groups in the form of polymers. In the infrared spectrum at 1646cm -1 The characteristic absorption peak of carbonyl group appears on the left and right and the absorptio...

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Abstract

The invention provides polybenzimidazole with a sulfonated side chain. The content of sulfonic acid groups in polybenzimidazole is controllable. The polybenzimidazole with the sulfonated side chain can be used for preparing a proton exchange membrane with high conductivity, good mechanical performance and low price. The invention further provides a preparation method for polybenzimidazole with the sulfonated side chain. In addition, the invention further provides the proton exchange membrane.

Description

technical field [0001] The invention relates to the field of polymers and their preparation, in particular to a side chain sulfonated polybenzimidazole and a preparation method thereof. Background technique [0002] Proton exchange membrane fuel cell (PEMFC) is regarded as a clean and efficient energy source in the 21st century due to its remarkable advantages such as high energy conversion rate, low temperature start-up, and no pollution. The proton exchange membrane is a key component of PEMFC, which mainly plays the role of conducting protons and isolating fuel and oxidant. At present, the commonly used proton exchange membranes are Nafion series perfluorosulfonic acid membranes produced by DuPont of the United States, but perfluorosulfonic acid membranes are expensive and have high methanol fuel permeability, so the development of new low-cost proton exchange membranes has become a research hotspot. Among them, sulfonated aromatic polymers such as polyetherketone, polye...

Claims

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Application Information

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IPC IPC(8): C08G73/18H01M8/02H01M2/16
CPCY02E60/12Y02E60/50
Inventor 徐铜文张正辉
Owner UNIV OF SCI & TECH OF CHINA