A kind of sulfur-modified thermosetting polymer proton exchange membrane and preparation method thereof

Abstract

The invention belongs to the field of polymer electrolyte materials for fuel cells, and particularly relates to a sulphur-modified thermosetting polymer proton exchange membrane and a preparation method thereof. The proton exchange membrane comprises a base body rubber material, a metal unsaturated sulfonate, a vulcanizing activator, a vulcanizing accelerator and sulphur. According to the preparation method, in-situ sulfonation modification and in-situ sulphur modification of rubber are simultaneously completed in a high-temperature hot-pressing process, sulfonic acid groups are effectively grafted on a rubber molecular chain, and a large amount of cyclical sulfides is generated, thus the glass-transition temperature of the rubber is greatly increased, the rubber is transformed into thermosetting plastics, and therefore excellent size stability, heat stability, chemical stability and electrochemical stability are endowed to the proton exchange membrane. The preparation method provided by the invention is simple in process, high in efficiency and low in cost, and is environmental-friendly; the prepared sulphur-modified thermosetting polymer proton exchange membrane has the advantages of high proton conductivity, low methanol permeability, high size stability and the like, and can meet the use requirement of a direct-methanol fuel cell.

Description

technical field [0001] The invention belongs to the field of fuel cell polymer electrolyte materials, in particular to a sulfur-modified thermosetting polymer proton exchange membrane and a preparation method thereof. Background technique [0002] As one of the key components of direct methanol fuel cells, the proton exchange membrane is responsible for the dual role of conducting protons and separating the anode and cathode, and should meet the following requirements: (1) high proton conductivity; (2) low methanol permeability; ( 3) Good thermal stability, chemical stability, and dimensional stability; (4) Good mechanical properties; (5) Low price. At present, perfluorosulfonic acid proton exchange membranes, represented by Nafion, which are widely used in medium and low temperature hydrogen fuel cells, have high proton conductivity and good chemical stability, but they are also expensive and have high methanol permeability. In addition, the fluorine-containing substances ...

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Problems solved by technology

The above methods all prepare a proton exchange membrane with a certain thickness through solution film formation. The disadvantages are: organic solvents are usually toxic and easy to cause pollution, the film formation time is long, the requirements for film formation conditions are high, and the process is relatively complicated.

Its disadvantages are: (1) the degree of sulfonation is not easy to control, because the sulfonation reaction process of direct sulfonation of chlorosulfonic acid is uncontrollable; The vulcanized rubber usually has an uneven distribution of sulfonate groups, resulting in poor performance of the membrane; (3) Chlorosulfonic acid is a strong oxidizing acid, its oxidizing property is stronger than that of concentrated sulfuric acid, and the safety of the operation process is poor

Patent CN102775628A reports the use of metal unsaturated sulfonate to prepare a polymer proton exchange membrane with a cross-linked structure, but the glass transition temperature of the obtained proton exchange membrane is lower than room temperature, and it is still an elastomer at room temperature , its dimensional stability, thermal stability, and electrochemical stability cannot be guaranteed, and the water absorption rate of the film is high

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