Method for enhancing fracture tensile strength of PBI/HP3O4 cast by sol-gel method

A technology of PBI-H3PO4 and tensile strength at break, which is applied in the field of material science and can solve the problem of low tensile strength at break of membranes

Inactive Publication Date: 2009-01-07
NORTHEASTERN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The present invention is aimed at the PBI/H cast by PBI-phosphoric acid sol-gel method 3 PO 4 To solve the problem of low tensile strength at break of the film, provide a PBI/H that enhances

Method used

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  • Method for enhancing fracture tensile strength of PBI/HP3O4 cast by sol-gel method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0051] Mix PBI powder and phosphoric acid solution with a mass concentration of 85%, add 8g of PBI powder per 100mL of 85wt% phosphoric acid solution, and heat to 200°C under nitrogen atmosphere to form a uniform reddish-brown PBI-H 3 PO 4 sol, then PBI-H 3 PO 4 The sol is poured on the flat plate, and the high-temperature PBI-H 3 PO 4 The sol is spread horizontally on the flat plate to form a high temperature PBI-H with a thickness of 0.05mm 3 PO 4 Sol film.

[0052] Will contain high temperature PBI-H 3 PO 4 Put the plate of the sol film horizontally in the refrigerator, freeze at -18±3°C for 24 hours, and then freeze the PBI / H 3 PO 4 The membrane is separated from the plate. Prepare a phosphoric acid solution with a mass concentration of 20%. PBI / H after freezing 3 PO 4 The membrane is completely soaked in the prepared phosphoric acid solution, sealed at room temperature, soaked in a nitrogen atmosphere for 1h, and the solution is mixed with PBI / H 3 PO 4 Intr...

Embodiment 2

[0057] High temperature PBI-H 3 PO 4 The preparation method of the sol film is the same as in Example 1, and the thickness is 0.10mm.

[0058] Will contain high temperature PBI-H 3 PO 4 Put the plate of the sol film horizontally in the refrigerator, freeze at -18±3°C for 28 hours, and then freeze the PBI / H 3 PO 4 The membrane is separated from the plate. Prepare a phosphoric acid solution with a mass concentration of 40%. PBI / H after freezing 3 PO 4 The membrane was completely soaked in the prepared phosphoric acid solution, sealed at room temperature, soaked in a nitrogen atmosphere for 2 hours, and the solution was mixed with PBI / H 3 PO 4 Intramembrane acid balance; then PBI / H 3 PO 4 The membrane was taken out, and the acid on the surface of the membrane was removed with filter paper.

[0059] In PBI / H 3 PO 4 Before the membrane was deformed, the PBI / H 3 PO 4 The membrane was fixed flat between two flat plates, and dried in an oven at 85±5°C for 9 hours; then...

Embodiment 3

[0062] High temperature PBI-H 3 PO 4 The preparation method of the sol film is the same as in Example 1, and the thickness is 0.20mm.

[0063] Will contain high temperature PBI-H 3 PO 4 Put the flat plate of the sol film horizontally in the refrigerator, freeze at -18±3°C for 36 hours, and then freeze the PBI / H 3 PO 4 The membrane is separated from the plate. Prepare a phosphoric acid solution with a mass concentration of 60%. PBI / H after freezing 3 PO 4 The membrane was completely soaked in the prepared phosphoric acid solution, sealed at room temperature, soaked in a nitrogen atmosphere for 3 hours, and the solution was mixed with PBI / H 3 PO 4 Intramembrane acid balance; then PBI / H 3 PO 4 The membrane was taken out, and the acid on the surface of the membrane was removed with filter paper.

[0064] In PBI / H 3 PO 4 Before the membrane was deformed, the PBI / H 3 PO 4 The film was fixed flat between two plates, and dried in an oven at 85±5°C for 10 hours; then th...

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Abstract

A method for enhancing the breaking tensile strength of a PBI/H3PO4 film which is cast by a sol-gel method is characterized in that the powders of poly2, 2'-(metaphenylene)-5, 5'- bisbenzimidazole (PBI) are mixed with a phosphoric acid (H3PO4) solution, and is heated up to the temperature of 190 to 200 DEG C under the condition of nitrogen environment to form homogeneous reddish-brown PBI-H3PO4 sol; then the PBI-H3PO4 sol is dumped on a flat plate, and the high temperature sol is horizontally spread on the flat plate by a film blade to form high temperature PBI-H3PO4 sol film with 0.05 to 0.50mm thickness, the sol film is gelated into the film under the condition of freezing and then is prepared into phosphoric doped PBI film with enhanced breaking tensile strength, which satisfies a proton exchange film fuel cell for the requirements of acid doping level aspects of film electrolyte, by the phosphoric acid solution immerse method, the phosphoric acid solution heating treatment method or the organic solvent heating treatment method. The method of the invention has a short operating cycle and simple, convenient and feasible processing steps, and is easy to operate; the breaking tensile strength of the PBI-H3PO4 film being treated by enhancement is 6 to 16 MPa.

Description

technical field [0001] The invention belongs to the field of material science, in particular to PBI / H casted by enhanced sol-gel method 3 PO 4 Method for film tensile strength at break. Background technique [0002] As a clean, efficient and stable power supply technology, proton exchange membrane fuel cell (PEMFC) has good application prospects in the development of green and environment-friendly automobiles, portable devices and other fields. High-temperature proton exchange membrane fuel cells (operating temperature 80-180°C) have become a research hotspot due to their advantages of simplifying water and heat management systems and improving CO tolerance. Phosphoric acid (H 3 PO 4 ) doped poly 2,2'-(m-phenylene)-5,5'-bibenzimidazole (PBI) film due to its outstanding thermal stability, good electrical conductivity, and low methanol permeability etc. have attracted the attention of researchers in the development of high-temperature PEMFC, and have been applied to the d...

Claims

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Application Information

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IPC IPC(8): C08J5/22C08L79/04C08K3/32
Inventor 何荣桓杨景帅车全通
Owner NORTHEASTERN UNIV
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