CN-117162553-B - Improved method for preparing perfluorosulfonic acid ion exchange membrane by melt extrusion blow molding, film prepared by method and application

Abstract

The invention provides an improved method for preparing a perfluorosulfonic acid ion exchange membrane by melt extrusion blow molding, a film prepared by the method and application thereof. The method comprises the steps of (1) fully mixing materials containing perfluorinated sulfonic acid fluorine-type resin, sulfonated graphene and an auxiliary agent in a stirrer according to a proportion, extruding and granulating by an exhaust type double-screw extruder, cooling, drying to obtain master batch, wherein the mass ratio of the perfluorinated sulfonic acid fluorine-type resin to the sulfonated graphene to the 2, 5-diamino-benzene disulfonic acid is 100:10-20:1-3, (2) putting the master batch in a single-screw extruder, melting and extruding, blowing and forming a film by a film blowing machine head, and cooling to obtain a perfluorinated sulfonic acid ionic film, (3) saponifying the perfluorinated sulfonic acid ionic film in the step (2) by using NaOH methanol solution to obtain a perfluorinated sulfonic acid sodium type perfluorinated sulfonic acid hydrogen type ion exchange film, or reacting the perfluorinated sulfonic acid ionic film in the step (2) with an HCl solution to obtain the perfluorinated sulfonic acid hydrogen type ion exchange film.

Inventors

• YANG DAWEI

Assignees

• 苏州科润新材料股份有限公司

Dates

Publication Date

20260505

Application Date

20230901

Claims (7)

1. 1. An improved process for preparing perfluorosulfonic acid ion exchange membrane by melt extrusion blow molding comprising the steps of: (1) Fully mixing materials containing perfluorosulfonic acid fluorine resin, sulfonated graphene and 2, 5-diamino terephthalenesulfonic acid in a stirrer according to a proportion, extruding and granulating by an exhaust type double-screw extruder, cooling and drying to obtain master batches, wherein the mass ratio of the perfluorosulfonic acid fluorine resin to the sulfonated graphene to the 2, 5-diamino terephthalenesulfonic acid is 100:10-20:1-3; (2) Putting the master batch in the step (1) into a single screw extruder, carrying out melt extrusion, carrying out blow molding to form a film through a film blowing machine head, and cooling to obtain a perfluorosulfonic acid ionic film; (3) And (3) saponifying the perfluorinated sulfonic acid ion membrane in the step (2) by using NaOH methanol solution to obtain a perfluorinated sodium sulfonate type perfluorinated sulfonic acid hydrogen type ion exchange membrane, or reacting the perfluorinated sulfonic acid ion membrane in the step (2) with HCl solution to obtain the perfluorinated sulfonic acid hydrogen type ion exchange membrane.
2. 2. The method of claim 1, wherein the vent holes of the vented twin-screw extruder in the step (1) are connected with a vacuum pump, the vacuum degree is 0.1-0.5MPa, the temperature of each section of the vented twin-screw extruder is 280-340 ℃, and the temperature of a machine head is 290-310 ℃.
3. 3. The method of claim 1, wherein the single screw extruder of step (2) has a temperature of from 260 ℃ to 330 ℃ for each stage and a die temperature of from 280 ℃ to 300 ℃.
4. 4. The method of claim 1, wherein the vented twin screw extruder of step (1) and the single screw extruder of step (2) have screws, barrels, and dies made of corrosion-resistant nickel-base alloy steel.
5. 5. The method of claim 1, wherein the sulfonated graphene has a number of layers less than 10, a radial dimension of 200nm to 800nm, a thickness of 6 to 500nm, and an s element content of 0.5 to 18wt%.
6. 6. A perfluorosulfonic acid ion exchange membrane prepared according to the method of any one of claims 1-5.
7. 7. The use of the perfluorosulfonic acid ion exchange membrane according to claim 6 for fuel cells, lithium cells, vanadium cells, chlor-alkali electrolysis, gas separation and photocatalysis.

Description

Improved method for preparing perfluorosulfonic acid ion exchange membrane by melt extrusion blow molding, film prepared by method and application Technical Field The invention relates to the field of preparation of perfluorosulfonic acid ion exchange membranes, in particular to an improved method for preparing a perfluorosulfonic acid ion exchange membrane by melt extrusion blow molding, and a membrane prepared by the method and application thereof. Background The perfluorinated sulfonic acid ion exchange membrane (PFSIEM) is a perfluorinated polymer with a polytetrafluoroethylene structure as a framework and a vinyl ether structure with sulfonate at the tail end as a side chain, has good chemical stability and thermal stability, and is a good ion exchange carrier, so PFSIEM is widely used in the fields of chlor-alkali ion membranes, fuel cell membranes and the like. The perfluorinated sulfonic acid ion exchange resin and the membrane have incomparable advantages of other materials in other various electrolytic preparation devices, electrodialysis, chemical catalysis, gas separation, gas drying, sewage treatment, sea water desalination and the like. At present, the perfluorosulfonic acid ion exchange membrane prepared by a melt extrusion blow molding method has the advantages of high thickness precision, uniform longitudinal and transverse strength, no need of trimming, flexible thickness and width change, higher production efficiency and the like. However, the blow molding of the perfluorosulfonic acid ion exchange membrane has a great technical difficulty, because the property of the perfluorosulfonic acid resin is not in accordance with the requirement of blow molding on the resin, for example, a small amount of volatile matters exist to adversely affect the blow molding of the film, a large number of pinhole-shaped air holes are easily formed due to the volatile matters, the resin is a shear-thinning non-Newtonian fluid, the melt viscosity of the resin is obviously changed along with the shear rate, the fluidity and the viscoelasticity of the resin are not in accordance with the requirement in the blow molding process, the film breakage and the like are easily generated, and the film formation is not easy. Disclosure of Invention In view of the problems existing in the background art, the invention aims to provide an improved method for preparing a perfluorosulfonic acid ion exchange membrane by melt extrusion blow molding, which is characterized in that perfluorosulfonic acid fluororesin is modified to meet the requirement of blow molding, so that the perfluorosulfonic acid ion exchange membrane with thinner and more uniform thickness, good dimensional stability and high mechanical strength is obtained, and the conductivity of the ionic membrane is improved after saponification or acidification treatment, so that the practical use requirement is met. The invention provides an improved method for preparing a perfluorosulfonic acid ion exchange membrane by melt extrusion blow molding, which comprises the following steps of (1) fully mixing materials containing perfluorosulfonic acid fluorine-type resin, sulfonated graphene and an auxiliary agent in a stirrer according to a proportion, extruding and granulating by an exhaust double-screw extruder, cooling and drying to obtain master batches, wherein the mass ratio of the perfluorosulfonic acid fluorine-type resin to the sulfonated graphene to 2, 5-diaminoterephthalic acid is 100:10-20:1-3, (2) putting the master batches in a single-screw extruder, performing melt extrusion, performing blow molding through a film blowing machine head, and cooling to obtain a perfluorosulfonic acid ion membrane, (3) saponifying the perfluorosulfonic acid ion membrane in the step (2) by using a methanol solution of NaOH to obtain a sodium perfluorosulfonic acid hydrogen ion exchange membrane, or reacting the perfluorosulfonic acid ion membrane in the step (2) with an HCl solution to obtain the perfluorosulfonic acid hydrogen ion exchange membrane. Optionally, the auxiliary agent is 2, 5-diamino terephthalenesulfonic acid. Optionally, the exhaust hole of the exhaust type double-screw extruder in the step (1) is connected with a vacuum pump, the vacuum degree is 0.1-0.5MPa, the temperature of each section of the exhaust type double-screw extruder is 280-340 ℃, and the temperature of a machine head is 290-310 ℃. Optionally, the temperature of each section of the single screw extruder in the step (2) is 260-330 ℃, and the temperature of the machine head is 280-300 ℃. Optionally, the vented twin screw extruder of step (1) and the single screw extruder of step (2) have screws, barrels, and dies made of corrosion-resistant nickel-base alloy steel. Optionally, the IEC value of the perfluorosulfonic acid ion membrane resin is 0.97-1.05. Optionally, the number of layers of the sulfonated graphene is smaller than 10, the radial dimension is 200-800 nm, the thickness is 6-500 nm, and t