Method for testing shear tolerance of ion exchange membrane

Abstract

The invention relates to a method for testing the shear tolerance of an ion exchange membrane, and belongs to the technical field of ion exchange membranes. Mechanical durability is one of main evaluation indexes of an ion exchange membrane, a single-cantilever mode of DMA test can test the stress change of a material under shear vibration, but the texture of the ion exchange membrane is too soft, and the ion exchange membrane cannot be used for the single-cantilever test of DMA. According to the invention, the hard sheets are additionally arranged on the two sides of the soft ion exchange membrane, so that the shear stress tolerance test of the ion exchange membrane is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of ion exchange membranes and relates to a shear tolerance test method for ion exchange membranes. Background Art

[0002] Ion exchange membranes, including cation exchange membranes and anion exchange membranes, are an important material in the field of hydrogen energy. Mechanical durability is one of the main evaluation indicators of this membrane for the application process. At present, the main testing methods are achieved through long-term experiments. Taking the proton exchange membrane used in fuel cells as an example, the testing method is to make the proton exchange membrane into a membrane electrode, apply a dry-wet cycle gas environment to the membrane electrode in the fuel cell, so that the membrane electrode will experience strain fatigue in the continuous dry-wet conversion, and test the ultimate mechanical strength of the proton exchange membrane. However, in addition to the tensile strain caused by dryness and wetness, ion exchange membranes are also faced with the risk of shear stress in applications, that is, at the joints of the device (for example, in fuel cells, the junction of the frame and carbon paper), the relative displacement of the two hard materials in the normal direction will exert shear force on the membrane at this location, which is also the main reason for the leakage of ion exchange membranes. So far, there is no effective method to judge the tolerance of ion exchange membranes to shear.

[0003] The single cantilever mode of DMA test can test the stress change of materials under shear vibration, but the texture of ion exchange membrane is too soft to be used for single cantilever test of DMA. Therefore, the present invention adds hard sheets on both sides of the ion exchange membrane by hot pressing method to solve the problem of too soft texture of ion exchange membrane. Summary of the invention

[0004] The object of the present invention is to provide a shear tolerance test method for an ion exchange membrane, which has the characteristic of being easy to detect.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A shear tolerance test method for an ion exchange membrane, wherein the specific operation process of the shear tolerance test method is as follows:

[0007] S1: Prepare the upper pressing plate and the lower pressing plate, punch positioning holes on the surface of the upper pressing plate, and install positioning pins at corresponding positions on the surface of the lower pressing plate;

[0008] S2: Cut the ion exchange membrane into long strips, make holes at both ends of the long strip ion exchange membrane according to the positions of the positioning holes, install the upper hard sheet and the lower hard sheet on both ends of the ion exchange membrane, make holes at the corresponding positions of the upper hard sheet and the lower hard sheet, install and confirm that a 1mm shear gap is reserved in the middle of the ion exchange membrane;

[0009] S3: After the ion exchange membrane and the upper and lower hard sheets are fixed in position, an upper pressing plate and a lower pressing plate are installed on the outside thereof, and the ion exchange membrane and the upper and lower hard sheets are further fixed by a laminating machine;

[0010] S4: Perform DMA single cantilever test on the ion exchange membrane and upper and lower hard sheets obtained by hot pressing in S3.

[0011] Furthermore, the surfaces of the upper and lower hard sheets are coated with hot melt adhesive.

[0012] Furthermore, the shear gap in S2 is 0.5 to 1 mm.

[0013] Furthermore, in S3, the temperature of the laminating machine is 80° C. and the speed is 0.3 m / s.

[0014] DMA test, i.e. dynamic thermomechanical analysis test, is a test method for accurately determining the viscoelasticity, Young's modulus (E*) or shear modulus (G*) of a material by applying a vibration of known amplitude and frequency to a material sample, measuring the applied displacement and the generated force. It is commonly used to study the thermomechanical properties of materials, especially their performance at different temperatures. DMA test can apply stress to the sample by shear, measure the modulus as a function of time or temperature, and thus provide phase change information. This method can reveal the performance changes of the material during heating or cooling, and help to understand the thermal stability and mechanical properties of the material. The results of the DMA test include the glass transition temperature range, the viscosity flow temperature or melting temperature, the secondary relaxation transition temperature, the mechanical loss capacity, and the mechanical properties at different temperatures or frequencies. These data are of great significance for material research and development, quality control, and product performance evaluation. The present invention uses hot melt adhesive to stick the ion exchange membrane to the hard sheet.

[0015] Since the ion exchange membrane is soft and difficult to be shear tested, the present invention uses a laminator (or other thermal composite equipment) to fix the upper and lower hard plates on both sides of the ion exchange membrane with upper and lower pressing plates, and reserves a gap of 0.5 to 1 mm. The reserved gap can easily complete the DMA shear stress tolerance test.

[0016] Beneficial effects of the present invention:

[0017] By adding hard sheets on both sides of the soft ion exchange membrane, the shear stress tolerance test of the ion exchange membrane can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0019] Figure 1 A method of fixing the upper and lower hard sheets to the ion exchange membrane by heat pressing;

[0020] Figure 2 DMA single cantilever test method;

[0021] Figure 3 Example 1 Ion exchange membrane temperature scanning curve;

[0022] Figure 4 Example 2 Ion exchange membrane time scan curve;

[0023] Figure 5 Example 3 Ion exchange membrane frequency scanning curve. DETAILED DESCRIPTION

[0024] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0025] Example 1

[0026] S1: Prepare the upper pressing plate and the lower pressing plate, punch positioning holes on the surface of the upper pressing plate, and install positioning pins at corresponding positions on the surface of the lower pressing plate;

[0027] S2: Cut the ion exchange membrane into long strips, make holes at both ends of the long strip ion exchange membrane according to the positions of the positioning holes, install the upper hard sheet and the lower hard sheet on both ends of the ion exchange membrane, make holes at the corresponding positions of the upper hard sheet and the lower hard sheet, install and confirm that a 1mm shear gap is reserved in the middle of the ion exchange membrane;

[0028] S3: After the ion exchange membrane and the upper and lower hard sheets are fixed in position, an upper pressing plate and a lower pressing plate are installed on the outside thereof, and the ion exchange membrane and the upper and lower hard sheets are further fixed by a laminating machine, and the laminating machine temperature is 80°C and the speed is 0.3m / s;

[0029] S4: The ion exchange membrane and the upper and lower hard sheets obtained by hot pressing in S3 are subjected to DMA single cantilever test. In this embodiment, the test is carried out at 1 Hz and the temperature is scanned. The test results are as follows: Figure 3 shown.

[0030] Example 2

[0031] S1: Prepare the upper pressing plate and the lower pressing plate, punch positioning holes on the surface of the upper pressing plate, and install positioning pins at corresponding positions on the surface of the lower pressing plate;

[0032] S2: Cut the ion exchange membrane into long strips, make holes at both ends of the long strip ion exchange membrane according to the positions of the positioning holes, install the upper hard sheet and the lower hard sheet on both ends of the ion exchange membrane, make holes at the corresponding positions of the upper hard sheet and the lower hard sheet, install and confirm that a 1mm shear gap is reserved in the middle of the ion exchange membrane;

[0033] S3: After the ion exchange membrane and the upper and lower hard sheets are fixed in position, an upper pressing plate and a lower pressing plate are installed on the outside thereof, and the ion exchange membrane and the upper and lower hard sheets are further fixed by a laminating machine, and the laminating machine temperature is 80°C and the speed is 0.3m / s;

[0034] S4: The ion exchange membrane and the upper and lower hard sheets obtained by hot pressing in S3 are subjected to DMA single cantilever test. In this embodiment, the stress-time curve test is carried out at 100°C and 30Hz. The test results are as follows: Figure 4 shown.

[0035] Example 3

[0036] S1: Prepare the upper pressing plate and the lower pressing plate, punch positioning holes on the surface of the upper pressing plate, and install positioning pins at corresponding positions on the surface of the lower pressing plate;

[0037] S2: Cut the ion exchange membrane into long strips, make holes at both ends of the long strip ion exchange membrane according to the positions of the positioning holes, install the upper hard sheet and the lower hard sheet on both ends of the ion exchange membrane, make holes at the corresponding positions of the upper hard sheet and the lower hard sheet, install and confirm that a 1mm shear gap is reserved in the middle of the ion exchange membrane;

[0038] S3: After the ion exchange membrane and the upper and lower hard sheets are fixed in position, an upper pressing plate and a lower pressing plate are installed on the outside thereof, and the ion exchange membrane and the upper and lower hard sheets are further fixed by a laminating machine, and the laminating machine temperature is 80°C and the speed is 0.3m / s;

[0039] S4: Perform DMA single cantilever test on the ion exchange membrane and upper and lower hard sheets obtained by hot pressing in S3. In this embodiment, a frequency sweep test is performed at 100°C. The test results are as follows: Figure 5 shown.

[0040] When the present invention is used:

[0041] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A shear tolerance test method for an ion exchange membrane, characterized in that: The specific operation process of the shear tolerance test method is as follows: S1: Prepare the upper pressing plate and the lower pressing plate, punch positioning holes on the surface of the upper pressing plate, and install positioning pins at corresponding positions on the surface of the lower pressing plate; S2: Cut the ion exchange membrane into long strips, make holes at both ends of the long strip ion exchange membrane according to the positions of the positioning holes, install the upper hard sheet and the lower hard sheet on both ends of the ion exchange membrane, make holes at the corresponding positions of the upper hard sheet and the lower hard sheet, install and confirm that a 1mm shear gap is reserved in the middle of the ion exchange membrane; S3: After the ion exchange membrane and the upper and lower hard sheets are fixed in position, an upper pressing plate and a lower pressing plate are installed on the outside thereof, and the ion exchange membrane and the upper and lower hard sheets are further fixed by a laminating machine; S4: Perform DMA single cantilever test on the ion exchange membrane and upper and lower hard sheets obtained by hot pressing in S3.

2. The shear tolerance test method of an ion exchange membrane according to claim 1, characterized in that: The upper and lower hard sheets are coated with hot melt adhesive on the side contacting the ion exchange membrane.

3. The shear tolerance test method of an ion exchange membrane according to claim 1, characterized in that: The shear gap in S2 is 0.5-1 mm.

4. The shear tolerance test method of an ion exchange membrane according to claim 1, characterized in that: In S3, the temperature of the laminating machine is 80° C. and the speed is 0.3 m / s.

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