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Modified expanded polytetrafluoroethylene, preparation method thereof, composite ion exchange membrane and application thereof

A technology of polytetrafluoroethylene and composite ions, which is applied in the direction of ion exchange, ion exchange treatment devices, chemical instruments and methods, etc., can solve the problems of e-PTFE stability and poor uniformity, and achieve good uniformity and stability Effect

Active Publication Date: 2021-12-03
国家电投集团氢能科技发展有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The main purpose of the present invention is to provide modified e-PTFE, its preparation method, composite ion exchange membrane and its application, to solve the problems of poor stability and uniformity of e-PTFE in the prior art

Method used

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  • Modified expanded polytetrafluoroethylene, preparation method thereof, composite ion exchange membrane and application thereof
  • Modified expanded polytetrafluoroethylene, preparation method thereof, composite ion exchange membrane and application thereof
  • Modified expanded polytetrafluoroethylene, preparation method thereof, composite ion exchange membrane and application thereof

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preparation example Construction

[0032] In another typical embodiment of the present application, a preparation method of modified e-PTFE is provided, the preparation method includes: Step S1, impregnating and filling the freezing medium into the pores of e-PTFE to obtain wet material ; Step S2, crystallize at least part of the freezing medium in the wet material to obtain a solid material; Step S3, freeze-dry the solid material to obtain modified e-PTFE.

[0033] In this application, the freezing medium is impregnated and filled into the pores of e-PTFE. After the freezing medium is solidified into a solid, the crystals are highly oriented and the volume expands, and the e-PTFE also expands. The freeze-drying method is then used to remove the freezing medium, which can maintain the structural size of the porous material, thereby maintaining a structure similar to that in the filling state of the freezing medium after removing the freezing medium. The modified e-PTFE prepared by the method of the present appl...

Embodiment 1

[0062] 9 parts by mass of dimethyl sulfoxide and 1 part by mass of water were mixed at 25° C. to form a liquid freezing medium. Use a scraper to scrape the above-mentioned freezing medium, soak 0.05 parts by mass of e-PTFE-1 in the above-mentioned liquid freezing medium for 6 hours, make the liquid completely infiltrate and fill the pores of e-PTFE-1, and obtain wet material e-PTFE-1 . The wet material e-PTFE-1 was ice-crystallized at -30°C for 0.5 h to obtain a solid material. Put the solid material into the freeze-drying equipment, freeze-dry at 0.1Pa ~ 20Pa for 12 h. The initial freeze-drying temperature is -40°C, and the temperature rises slowly during the freeze-drying process at a rate of 5°C / h. After freeze-drying, the modified e-PTFE-1 was obtained. The contact angle between the modified e-PTFE-1 and the perfluorosulfonic acid resin solution at 16s is as follows: figure 2 shown. The properties of modified e-PTFE-1 are shown in Table 1.

Embodiment 2

[0064] The difference from Example 1 is that 1 part by mass of e-PTFE-1 is soaked in the above-mentioned liquid freezing medium.

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Abstract

The invention provides modified expanded polytetrafluoroethylene, a preparation method thereof, a composite ion exchange membrane and application thereof. The average aperture of the modified expanded polytetrafluoroethylene is 0.05-0.5 [mu] m, the porosity is 50-95%, the aperture distribution of more than 99% of pores of the modified expanded polytetrafluoroethylene is within + / -10% of the most probable aperture, and the dispersion coefficient of gram weight of the modified expanded polytetrafluoroethylene is less than 10%. The modified e-PTFE is narrow in pore size distribution, the dispersion coefficient of gram weight is smaller than 10%, so that the modified e-PTFE is good in uniformity; and the modified expanded polytetrafluoroethylene can still keep good mechanical performance when the average pore size and porosity are controlled within the range, so that the modified e-PTFE is good in stability.

Description

technical field [0001] The invention relates to the technical field of modified expanded polytetrafluoroethylene, in particular to modified expanded polytetrafluoroethylene, a preparation method thereof, a composite ion exchange membrane and applications thereof. Background technique [0002] At present, the ion exchange membranes of all vehicle fuel cells are prepared on the basis of perfluorosulfonic acid resin (PFSA), which is mainly determined by two factors: safety, reliability and full life cycle cost. DuPont took the lead in developing the first generation of PFSA ion exchange membrane commercial products in the 1990s, including Nafion112, Nafion115 and Nafion117. This generation of products adopts the melt extrusion process and has good stability and mechanical properties. The second-generation Nafion membrane adopts the solution casting membrane process to reduce the cost, such as Nafion211, Nafion212. In order to solve the problem of the large thickness of the io...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J9/40C08J9/26C08J5/22C08L27/18B01J47/00
CPCC08J9/40C08J9/26C08J5/2237B01J47/00C08J2327/18C08J2201/0482C08J2201/0484
Inventor 贾雯迪张泽天刘昊董天都刘一晨李道喜李丹周朝毅
Owner 国家电投集团氢能科技发展有限公司