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CN-116544472-B - PPTA modified perfluorinated sulfonic acid proton exchange membrane and preparation method thereof

CN116544472BCN 116544472 BCN116544472 BCN 116544472BCN-116544472-B

Abstract

The invention discloses a PPTA modified perfluorosulfonic acid proton exchange membrane and a preparation method thereof, wherein the PPTA modified perfluorosulfonic acid proton exchange membrane is of a layered structure, an intermediate layer is a perfluorosulfonic acid polymer and PPTA mixed layer, and the preparation method of the perfluorosulfonic acid polymer and PPTA mixed layer comprises the steps of mixing a pore-forming agent, PPTA resin and concentrated sulfuric acid, stirring until the pore-forming agent and the PPTA resin are uniformly dispersed in the concentrated sulfuric acid, and carrying out vacuum deaeration to obtain PPTA porous casting membrane liquid; the PPTA porous casting film liquid is coated on a substrate in a scraping way, the substrate is put into pure water, the substrate is peeled off after solidification, the substrate is soaked in ultrafiltration water to obtain a PPTA porous film, the PPTA porous film is soaked in the perfluorosulfonic acid casting film liquid, and the perfluorosulfonic acid polymer and PPTA mixed layer is obtained after soaking and drying, so that the thermal stability, the mechanical strength and the swelling resistance of the film can be improved by the perfluorosulfonic acid polymer and the PPTA mixed layer, and the membrane also has the advantage of reducing the methanol permeability. The proton conductivity of the composite membrane is increased.

Inventors

  • Su bihai
  • YUAN HAICHAO
  • XU FENG
  • Jia Paipai
  • WANG XIAOJING
  • GAO YANG
  • YANG RONGQIAN

Assignees

  • 河北金力新能源科技股份有限公司

Dates

Publication Date
20260505
Application Date
20230522

Claims (14)

  1. 1. A PPTA modified perfluorinated sulfonic acid proton exchange membrane is characterized by being of a layered structure and comprising an upper layer, a middle layer and a lower layer, wherein the upper layer, the middle layer and the lower layer are sequentially arranged from top to bottom, The middle layer is a mixed layer of perfluorinated sulfonic acid polymer and PPTA; the upper layer and the lower layer are both Nafion resin layers; the preparation method of the mixed layer of the perfluorosulfonic acid polymer and the PPTA comprises the following steps: s1, mixing a pore-forming agent, PPTA resin and concentrated sulfuric acid to obtain a first mixture, stirring the first mixture until the pore-forming agent and the PPTA resin are uniformly dispersed in the concentrated sulfuric acid to obtain a second mixture, and carrying out vacuum defoaming on the second mixture to obtain PPTA porous casting film liquid; S2, the PPTA porous casting film liquid is coated on a substrate in a scraping mode, the substrate is placed in pure water, the substrate is peeled off after solidification, and the substrate is placed in ultrafiltration water to be soaked for 15-30 hours, so that a PPTA porous film is obtained; S3, immersing the PPTA porous membrane into perfluorosulfonic acid casting solution, and drying in a vacuum environment after immersing for 0.5-1.5 h to obtain a perfluorosulfonic acid polymer and PPTA mixed layer, wherein the perfluorosulfonic acid casting solution is a solution formed by dissolving Nafion resin in a solvent.
  2. 2. The PPTA modified perfluorosulfonic acid proton exchange membrane according to claim 1, wherein in S1 said porogen is PEG.
  3. 3. The PPTA modified perfluorinated sulfonic acid proton exchange membrane according to claim 1, wherein in S1, the ratio of the pore-forming agent to the PPTA resin is (1-5) (1-6) in parts by weight.
  4. 4. The PPTA modified perfluorinated sulfonic acid proton exchange membrane according to claim 1, wherein in S1, the ratio of the parts by weight of the pore-forming agent to the parts by volume of the concentrated sulfuric acid is (1-5) (10-25), the parts by weight are mg, the parts by volume are mL, and the concentration of the concentrated sulfuric acid is more than or equal to 97wt%.
  5. 5. The PPTA modified perfluorosulfonic acid proton exchange membrane according to claim 1, wherein in S3, said solvent is one or more of N-methylpyrrolidone, N dimethylformamide, tetrahydrofuran, acetone and ethanol.
  6. 6. The PPTA modified perfluorosulfonic acid proton exchange membrane according to claim 1, wherein in S3, the Nafion resin is dissolved in the solvent by stirring at 60-120 ℃ for 1-10 hours.
  7. 7. The PPTA modified perfluorosulfonic acid proton exchange membrane according to claim 1, wherein the concentration of Nafion resin in the perfluorosulfonic acid casting solution in S3 is 10 to 30wt%.
  8. 8. The PPTA modified perfluorosulfonic acid proton exchange membrane according to claim 1, wherein in S3, the Nafion resin is obtained by drying Nafion solution at 80-100 ℃ for 4-8 hours.
  9. 9. The PPTA modified perfluorosulfonic acid proton exchange membrane according to claim 1, wherein in S3, the drying temperature is 60 to 120 ℃ and the drying time is 5 to 10 hours.
  10. 10. The PPTA modified perfluorosulfonic acid proton exchange membrane according to claim 1, wherein in S1, the stirring speed is 300 to 1000r/min, the stirring time is 1 to 5 hours, and the stirring temperature is 50 to 100 ℃.
  11. 11. The PPTA modified perfluorosulfonic acid proton exchange membrane according to claim 1, wherein the PPTA modified perfluorosulfonic acid proton exchange membrane has a thickness of 10-70 μm; The thickness of the intermediate layer is 10-50 mu m.
  12. 12. The preparation method of the PPTA modified perfluorinated sulfonic acid proton exchange membrane according to any one of claims 1 to 11, which is characterized by comprising the steps of coating perfluorinated sulfonic acid casting solution on the two side surfaces of the intermediate layer to obtain a composite membrane, and drying the composite membrane after the perfluorinated sulfonic acid casting solution is fully soaked.
  13. 13. The method according to claim 12, wherein the time for the perfluorosulfonic acid casting solution to sufficiently infiltrate is 1 to 2 hours.
  14. 14. The method according to claim 12, wherein the condition for drying the composite film is a temperature of 60 to 120 ℃ for 5 to 10 hours.

Description

PPTA modified perfluorinated sulfonic acid proton exchange membrane and preparation method thereof Technical Field The invention belongs to the technical field of batteries, and particularly relates to a PPTA modified perfluorinated sulfonic acid proton exchange membrane and a preparation method thereof. Background Along with the increasing serious environmental pollution and energy crisis problems, green renewable energy has become an urgent need of the present society, and Proton Exchange Membrane Fuel Cells (PEMFCs) are expected to be a high-efficiency and environment-friendly energy device, and have very broad application prospects. As a current research hot spot, the proton exchange membrane fuel cell does not involve the combustion process of hydrogen and oxygen in the power generation process, so the proton exchange membrane fuel cell is not limited by the Carnot cycle, and has higher energy conversion rate. Among them, direct methanol fuel cells called sixth generation fuel cells have attracted much attention in various fields such as industry and academia. Proton exchange membranes are one of the core components, and should have high proton conductivity, mechanical properties and resistance to swelling. The perfluorinated sulfonic acid proton exchange membrane (Nafion) used at present has excellent electrochemical performance, acceptable mechanical strength and good oxidation stability, but has poor blocking effect on methanol fuel, high fuel permeability, larger water swelling, easy degradation under high temperature conditions, low proton conductivity under low humidity conditions, high cost and incapability of fully playing the performance advantages of direct methanol fuel cells. Accordingly, more and more research is being directed to the development of fluorine-containing or non-fluorine-containing proton exchange membranes. CN106159301a discloses a preparation method of perfluorosulfonic acid proton exchange membrane, the invention provides a preparation method of perfluorosulfonic acid proton exchange membrane by electrophoresis, the method has simple preparation process, easy operation, short preparation time and easy industrial production. However, the invention fails to improve the mechanical stability of the perfluorosulfonic acid proton exchange membrane. CN104558649a discloses a PVDF modified perfluorosulfonic acid proton exchange membrane and a preparation method thereof. According to the invention, PVDF is uniformly compounded into the perfluorosulfonic acid proton exchange membrane through ammonia water crosslinking, so that the mechanical stability and the dimensional stability of the composite proton exchange membrane are effectively improved, and the methanol permeability is reduced, but the proton conductivity is not improved to a great extent, and the practical application of the composite proton exchange membrane is limited. Disclosure of Invention Aiming at the defects of the prior art, the invention aims to provide a preparation method of a perfluorosulfonic acid proton exchange membrane modified by PPTA, which is characterized in that perfluorosulfonic acid and a PPTA porous membrane are compounded to obtain a perfluorosulfonic acid polymer and PPTA mixed layer, so that the mechanical strength and swelling resistance of the membrane are improved, the methanol permeability is reduced, and simultaneously, perfluorosulfonic acid casting membrane liquid is coated on the upper side and the lower side of the perfluorosulfonic acid polymer and PPTA mixed layer, so that the proton conductivity of the composite membrane can be increased to a certain extent. The invention further aims to provide a PPTA modified perfluorinated sulfonic acid proton exchange membrane. The invention is realized by the following technical scheme. A preparation method of a mixed layer of a perfluorinated sulfonic acid polymer and PPTA comprises the following steps: S1, mixing a pore-forming agent, PPTA resin (poly-paraphenylene terephthalamide resin) and concentrated sulfuric acid to obtain a first mixture, stirring the first mixture until the pore-forming agent and the PPTA resin are uniformly dispersed in the concentrated sulfuric acid to obtain a second mixture, and carrying out vacuum defoaming on the second mixture to obtain PPTA porous casting film liquid; In S1, the porogen is PEG. In the step S1, the stirring speed is 300-1000 r/min, and the stirring time is 1-5 h. In S1, the temperature of stirring is 50-100 ℃. In the S1, the ratio of the pore-forming agent to the PPTA resin is (1-5) (1-6) in parts by weight. In S1, the concentration of the concentrated sulfuric acid is more than or equal to 97 percent. In S1, the ratio of the mass parts of the pore-forming agent to the volume parts of the concentrated sulfuric acid is (1-5): (10-25), the unit of the mass parts is mg, and the unit of the volume parts is mL. S2, the PPTA porous casting film liquid is coated on a substrate in a scraping mode, the s