Sample for testing mechanical properties of porous membrane material and preparation and testing method thereof

Abstract

The application relates to the field of membrane material testing, in particular to a sample for testing the mechanical properties of a porous membrane material and a preparation method and a testing method thereof. The preparation method comprises the following steps: determining a pore region contained in a sample to be tested, arranging a clamping edge and a stretching edge which wrap the pore region and are free of holes at the edge of the pore region, the clamping edge is used for providing a site for clamping of a testing device, and the stretching edge is used for providing stretching support, the width of the stretching edge is L, 2d < L < 200d, wherein d is the horizontal center distance between two adjacent pores perpendicular to the stretching direction; the length of the clamping edge is W, M + 2s < W < M + 200s, M is the depth of a fixture of the testing device, and s is the maximum vertical distance of the centers of the outermost adjacent two pores in the stretching direction. When the sample is used for mechanical property testing, the obtained mechanical test results have good repeatability and high accuracy.

Description

Technical Field

[0001] This invention relates to the field of membrane material testing, specifically to a sample for testing the mechanical properties of porous membrane materials, and its preparation and testing methods. Background Technology

[0002] Porous membrane materials refer to membrane structures with uniformly or non-uniformly distributed pores. Porous membranes are suitable for sieving substances in liquids and / or gases by the size of the pores and are widely used in fields such as biomedicine, water treatment, petrochemical production, battery manufacturing, and substance detection.

[0003] Porous membrane materials are subjected to thermal expansion and contraction, compression and bending during assembly, and impact from liquids during use, which puts stress on the porous membrane. Excessive external force can cause the porous membrane to rupture, thus preventing it from performing its corresponding functions. Therefore, porous membrane materials need to undergo mechanical property testing before leaving the factory after production.

[0004] When testing the mechanical properties of porous membrane materials, it is usually necessary to prepare porous membrane samples in advance, fix the ends of the porous membrane samples on the testing instrument, collect the data, and repeat the test on multiple porous membrane samples to determine whether the mechanical properties of the corresponding porous membrane materials meet the requirements.

[0005] Current porous membrane samples are obtained by cutting porous membrane materials to suitable sizes. (See...) Figure 1 and Figure 2 As shown, due to the presence of numerous uniformly or non-uniformly distributed pores on the surface of porous membrane materials, and the varying sizes of these pores, cutting can lead to localized stress concentration if the cutting line is located within the pore area, causing pore rupture. This results in a decrease in the mechanical properties of the corresponding porous membrane sample. Even if the cutting does not occur within the pore area, different samples of the same porous membrane material exhibit significant differences in mechanical properties, leading to low repeatability. Consequently, it becomes difficult to accurately reflect the mechanical properties of the porous membrane material, resulting in low test accuracy and a high risk of misjudgment. Consequently, unqualified products must be discarded and remanufactured, leading to resource waste and increased production costs. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention proposes a sample preparation method for testing the mechanical properties of porous membrane materials. When the test samples prepared by this method are subjected to mechanical property testing, the results show good repeatability and high accuracy, reducing the differences in mechanical property test results of porous membrane materials caused by human error in test sample preparation.

[0007] In a first aspect, the present invention provides a sample preparation method for testing the mechanical properties of porous membrane materials, comprising the following steps: determining the pore region contained in the sample to be tested; setting a clamping edge and a stretching edge that surround the pore region and are without pores at the edge of the pore region; the two clamping edges are arranged opposite to each other; the two stretching edges are arranged opposite to each other; the clamping edge is used to provide a clamping point for the testing equipment; the stretching edge is used to provide tensile support; the width of the stretching edge is L, 2d < L < 200d, where d is the maximum horizontal distance between the centers of the two outermost adjacent pores perpendicular to the stretching direction;

[0008] The length of the clamping edge is W, M+2s<W<M+200s, where M is the depth of the test equipment clamp, s is the maximum vertical distance between the centers of the two outermost adjacent holes along the tensile direction, and the depth refers to the length required in the clamping direction of the test equipment.

[0009] According to an embodiment of the present invention, 10d < L < 150d, preferably 30d < L < 120d, and further, 50d < L < 100d, for example, L is any point value or any range of two point values ​​among 8d, 15d, 25d, 35d, 40d, 50d, 60d, 70d, 80d, 90d, 110d, 115d, 130d, and 145d.

[0010] According to an embodiment of the present invention, M+10s < W < M+150s, preferably M+50s < W < M+100s, and more preferably M+60s < W < M+80s. For example, W is any point value or a range of any two points among M+s, M+10s, M+20s, M+30s, M+40s, M+50s, M+60s, M+70s, M+80s, M+90s, M+100s, M+110s, M+120s, M+130s, M+140s, and M+150s.

[0011] According to an embodiment of the present invention, setting non-porous clamping edges and stretching edges at the edge of the pore region includes the following steps: determining that the length of one set of non-porous sides opposite the pore edge in the current sample to be tested is greater than M+2s, and the width of another set of non-porous sides is greater than 2d, and cutting the edge of the sample to be tested to obtain a sample film with a clamping edge length greater than M+2s and a stretching edge width greater than 2d.

[0012] According to an embodiment of the present invention, if it is determined that the length of a set of non-porous sides opposite the pore edge in the current sample to be tested is less than or equal to M+2s, and / or the width of another set of non-porous sides is less than or equal to 2d, a sample membrane containing the current pore region is re-prepared, and the length of the clamping edge in the sample membrane is greater than M+2s, and the width of the stretching edge is greater than 2d.

[0013] According to an embodiment of the present invention, the pore size of the porous membrane is 30-3000 μm, preferably 50-1000 μm, and more preferably 100-500 μm.

[0014] According to an embodiment of the present invention, the pores of the porous membrane are uniformly or non-uniformly distributed.

[0015] According to an embodiment of the present invention, the porous membrane may have the same or different pore sizes.

[0016] According to an embodiment of the present invention, the pores on the porous membrane are circular, elliptical, strip-shaped, rhomboid, triangular, trapezoidal, other polygonal or other patterned graphic structures, such as circular.

[0017] According to an embodiment of the present invention, the porous membrane is a single-layer structure or a multi-layer structure, for example, a 1 to 10-layer structure. Preferably, the different layers of the porous membrane have the same or different structures.

[0018] According to an embodiment of the present invention, the thickness of the porous membrane is 100 nm to 200 μm.

[0019] According to an embodiment of the present invention, the porous membrane is made of metal, metal oxide, or polymer.

[0020] According to an embodiment of the present invention, the metal is one or more of copper, gold, silver, aluminum, lead, titanium, cadmium, zinc, platinum, indium, and selenium.

[0021] According to an embodiment of the present invention, the metal oxide is one or more of silver oxide, copper oxide, cuprous oxide, aluminum oxide, lead oxide, titanium dioxide, titanium tetrachloride, nickel oxide, zinc oxide, cadmium oxide, and platinum oxide.

[0022] According to an embodiment of the present invention, the polymer is polymerized by polymer monomers selected from the group consisting of ethylene, pyrrole, thiophene, aniline, styrene, vinylacetic acid, 3-vinylpyridine, vinyltoluene, vinyl silicone oil, vinyl sulfonic acid, vinyl benzyl chloride, 1-vinylimidazolium, 2-vinylpyrazine, 2-vinylthiophene, 2-vinylaniline, 3-vinylpyridine, 3-vinylaniline, 4-vinylpyridine, N-vinylcarbazole, vinylcyclohexane, vinylsulfonyl chloride, sodium vinylsulfonate, styrene, phenylvinyl sulfone, 3-vinylbenzoic acid, 4-vinylbenzoic acid, N-vinylacetamide, and 4-hydroxybutylvinyl... The polymer is at least one of the following: ether, N-vinylpyrrolidone, dodecyl vinyl ether, allyl vinyl sulfonic acid, 2-vinyl-1,3-dioxolane, acrylic acid, acrylamide, 2-methyl-1-vinylimidazolium, triethylene glycol divinyl ether, vinyl acetate, diethylene glycol monovinyl ether, polyethylene glycol methyl ether methacrylate, acryloyl chloride, acrylic anhydride, 2-phenylacrylic acid, 4-acryloylmorpholine, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxyethyl acrylate, N-vinylcaprolactam, acrylonitrile, and ethylene glycol monovinyl ether, for example, the polymer being one or more of polypyrrole, polythiophene, polyaniline, poly(p-styrene), poly(p-phenylene), and their derivatives.

[0023] Secondly, the present invention also provides a sample for testing the mechanical properties of porous membrane materials prepared by the above method. The sample includes a pore region and a clamping edge and a stretching edge disposed at the edge of the pore region. The clamping edge is used to provide a clamping point for the testing equipment, and the stretching edge is used to provide tensile support to prevent stress concentration. The width of the stretching edge is L, 2d < L < 200d, where d is the maximum horizontal distance between the centers of the two outermost adjacent pores perpendicular to the stretching direction.

[0024] The length of the clamping edge is W, M+2s<W<M+200s, where M is the depth of the clamping device, 2mm≤M≤20mm, s is the maximum vertical distance between the centers of the two outermost adjacent holes along the tensile direction, and the depth refers to the length required by the clamping direction of the testing device.

[0025] According to an embodiment of the present invention, 10d < L < 150d, preferably 30d < L < 120d, and further, 50d < L < 100d, for example, L is any point value or any range of two point values ​​among 8d, 15d, 25d, 35d, 40d, 50d, 60d, 70d, 80d, 90d, 110d, 115d, 130d, and 145d.

[0026] According to an embodiment of the present invention, the length is M+10s < W < M+150s, preferably M+50s < W < M+100s, and more preferably M+60s < W < M+80s. For example, W is any point value or a range of any two points among M+s, M+10s, M+20s, M+30s, M+40s, M+50s, M+60s, M+70s, M+80s, M+90s, M+100s, M+110s, M+120s, M+130s, M+140s, and M+150s.

[0027] According to an embodiment of the present invention, the pore distribution, thickness, pore diameter and material of the porous membrane are defined as described above.

[0028] Thirdly, the present invention also provides a method for testing the mechanical properties of porous membrane material samples as described above, comprising the following steps:

[0029] The porous membrane material samples were fixed on a mechanical property testing instrument for testing, and test data were collected.

[0030] According to an embodiment of the present invention, fixing the porous membrane material sample on a mechanical property testing instrument includes: placing the porous membrane material sample in the testing area of ​​the mechanical property testing instrument and fixing the clamping edge of the porous membrane material sample.

[0031] According to an embodiment of the present invention, the test is a tensile test.

[0032] According to an embodiment of the present invention, the tensile test includes the following steps: using a tensile clamp to fix the porous membrane material sample relative to the two clamping edges, and uniformly stretching the porous membrane material sample along the tensile direction at a set tensile speed until the porous membrane material breaks.

[0033] According to an embodiment of the present invention, the tensile test further includes the following steps: recording the stress-strain curve and the degree of deformation; obtaining the tensile strength based on the stress-strain curve; and obtaining the elongation based on the degree of deformation.

[0034] Beneficial effects

[0035] The inventors unexpectedly discovered that when the width L of the stretched edge of the porous membrane sample satisfies 2d < L < 200d, where d is the maximum horizontal distance between the centers of the two outermost adjacent holes perpendicular to the stretching direction; and the length W of the clamping edge satisfies M+2s < W < M+200s, where s is the maximum vertical distance between the centers of the two outermost adjacent holes along the stretching direction, the mechanical test results obtained when the porous membrane sample is subjected to mechanical property testing show good repeatability and high accuracy. Compared with the prior art, where the mechanical properties of different samples from the same batch vary greatly, repeatability is low, and misjudgment is easy to occur, leading to resource waste and high production costs, the porous membrane sample of the present invention can effectively avoid misjudgment, thereby avoiding resource waste and reducing production costs. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of a porous membrane with a cut pore matrix arrangement in the prior art;

[0037] Figure 2 This is a schematic diagram of a porous membrane with staggered cut pores in the prior art;

[0038] Figure 3 This is a schematic diagram of s, d, w, and L in a porous membrane;

[0039] Figure 4 This is a schematic diagram of the preparation of a porous membrane material mechanical property test sample in Example 1 of the present invention;

[0040] Figure 5 This is a schematic diagram of the preparation of a porous membrane material mechanical property test sample in Example 2 of the present invention;

[0041] Figure 6 This is a schematic diagram of the porous membrane material mechanical property test sample prepared in Example 3 of the present invention. Detailed Implementation

[0042] The method of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0043] In the following examples, the mechanical properties of the membrane material were tested using an INSTRON68SC-1 universal testing machine. The required width of the clamping area on both sides was 10 mm (i.e., the M value mentioned above; the M value may vary depending on the testing equipment).

[0044] See Figure 3 The left image shows a porous copper film. Figure 3The right image is an enlarged view of the upper right corner of the left image. The right image shows that 's' is the vertical distance between the centers of the two outermost adjacent holes along the stretching direction, and 'd' is the horizontal distance between the centers of the two outermost adjacent holes perpendicular to the stretching direction. Figure 3 Since all the pore diameters in the membrane are the same, any two adjacent pores can satisfy the condition. When the porous membrane has pore diameters that are not the same, s is the maximum vertical distance between the centers of the two outermost adjacent pores along the stretching direction, and d is the maximum horizontal distance between the centers of the two outermost adjacent pores perpendicular to the stretching direction. In this invention, the horizontal distance refers to the distance perpendicular to the stretching direction, and the vertical distance refers to the distance parallel to the stretching direction.

[0045] Example 1

[0046] A sample preparation method for testing the mechanical properties of porous membrane materials includes the following steps:

[0047] S1, Select as follows Figure 4 The porous membrane shown in the left figure is a copper membrane with a thickness of 8 micrometers. It has the pore distribution shown in the figure, with a pore diameter of 200 micrometers. The maximum vertical distance s between the centers of the two outermost adjacent pores along the stretching direction is 450 micrometers. The maximum horizontal distance d between the centers of the two outermost adjacent pores perpendicular to the stretching edge direction is 400 micrometers. The length W corresponding to the edge of the porous membrane and the clamping edge is 12 millimeters, and the width corresponding to the stretching edge is 500 micrometers. L < 2d. Proceed to step S2.

[0048] S2. Prepare a porous membrane sample with an edge clamping length W of 13 mm and a stretching edge width L of 2 mm. The overall size of the porous membrane sample is 10 cm x 1.5 cm, and the pore distribution in the porous membrane is as follows: Figure 4 Same as shown.

[0049] Test Example 1

[0050] The tensile strength and elongation of five samples prepared using the method in Example 1 were tested using the universal testing machine described above. The test method is as follows: the sample clamping edge was fixed on the universal testing machine fixture, and the fixture was controlled to stretch the sample at a fixed speed of 50 mm per minute. The change curve of tensile stress with stretching distance was obtained until the sample was broken.

[0051] The maximum tensile stress is obtained from the tensile stress variation curve. Dividing this stress by the initial cross-sectional area of ​​the sample yields the tensile strength. The elongation is calculated based on the change in length of the sample in the tensile direction before and after stretching.

[0052] The tensile strengths of the five samples were 280 MPa, 277 MPa, 281 MPa, 275 MPa, and 286 MPa, respectively, and the elongations were 2.1%, 2.0%, 2.1%, 2.0%, and 2.1%, respectively. The differences in tensile strength and elongation among the different samples were small, indicating that the samples prepared in Example 1 had high repeatability and high test accuracy.

[0053] Comparative Example 1

[0054] With a thickness of 8 micrometers, having Figure 4 The porous copper film shown in the left figure was directly cut into samples with a size of 10 cm x 1.5 cm. The holes on the clamping edge and the stretching edge were cut off. As a control sample, the tensile strength and elongation of the five samples prepared in this comparative example were tested using the universal testing machine mentioned above, according to the method of Test Example 1.

[0055] The tensile strengths of the five samples tested were 220 MPa, 180 MPa, 165 MPa, 269 MPa, and 242 MPa, respectively, and the elongations were 1.1%, 0.9%, 0.7%, 1.3%, and 1.2%, respectively. Compared with the test results of Example 1, the tensile strength and elongation obtained using the samples of Comparative Example 1 decreased significantly. More significantly, the tensile strength and elongation of the five samples in Comparative Example 1 showed large differences, indicating poor repeatability of the test results and making it difficult for the test data to reflect the true mechanical properties of the samples.

[0056] Example 2

[0057] A sample preparation method for testing the mechanical properties of porous membrane materials includes the following steps:

[0058] S1, Select as follows Figure 5 The porous membrane shown in the left figure is a copper film with a thickness of 8 micrometers. This porous membrane has the following properties: Figure 5 The pore distribution shown has a pore diameter of 300 micrometers. The maximum vertical distance s between the centers of the two outermost adjacent pores along the stretching direction is 800 micrometers. The maximum horizontal distance d between the centers of the two outermost adjacent pores perpendicular to the stretching direction is 800 micrometers. The length W of the non-porous edge corresponding to the top and bottom of the porous membrane and the clamping edge is 15 millimeters. The width L of the non-porous edge corresponding to the left and right sides of the porous membrane and the stretching edge is 5 millimeters. W > 10 millimeters + 2s, L > 2d. Proceed to step S2.

[0059] S2. Retain 4 mm of the non-porous edges on the left and right sides of the sample to form a 4 mm wide stretching edge. Retain 14 mm of the non-porous edges on the top and bottom of the sample to form a 14 mm long clamping edge. Cut the sample to obtain a porous membrane sample with an overall size of 10 cm x 1.5 cm.

[0060] Using the universal testing machine described above, and following the method in Test Example 1, the tensile strength and elongation of the five samples prepared in this embodiment were tested.

[0061] The tensile strengths of the five samples were 288 MPa, 272 MPa, 281 MPa, 285 MPa, and 279 MPa, respectively, and the elongations were 2.2%, 2.0%, 2.1%, 2.2%, and 2.1%, respectively.

[0062] The small differences in tensile strength and elongation test results among different samples indicate that the samples prepared in this embodiment have good repeatability.

[0063] Example 3

[0064] A sample preparation method for testing the mechanical properties of porous membrane materials includes the following steps:

[0065] S1, Select as follows Figure 6 The porous membrane shown in the left figure is a copper film with a thickness of 6 micrometers. This porous membrane has the following properties: Figure 6 The pore distribution shown has a pore diameter of 100 micrometers. The maximum vertical distance s between the centers of the two outermost adjacent pores along the stretching direction is 300 micrometers. The maximum horizontal distance d between the centers of the two outermost adjacent pores perpendicular to the stretching direction is 300 micrometers. The length W of the non-porous edge corresponding to the clamping edge at the top and bottom of the porous membrane is 16 millimeters. The width L of the non-porous edge corresponding to the stretching edge on the left and right sides of the porous membrane is 6 millimeters. W > 10 millimeters + 2s, L > 2d. Proceed to step S2.

[0066] S2. Retain a 3 mm width for the non-porous areas on the left and right sides of the sample as stretching edges, and retain a 13 mm width for the non-porous edges on the top and bottom of the sample as clamping edges. Cut the sample to obtain an overall size of 12 cm x 1.2 cm.

[0067] The tensile strength and elongation of five samples prepared using the method described in this embodiment were tested using the universal testing machine and the method of Test Example 1.

[0068] The tensile strengths of the five samples were tested to be 312 MPa, 309 MPa, 311 MPa, 315 MPa, and 299 MPa, respectively, and the elongations were 0.8%, 0.7%, 0.8%, 0.8%, and 0.7%, respectively. The differences in tensile strength and elongation among the different samples were small, indicating that the samples prepared in this embodiment have good repeatability.

[0069] The specific embodiments of the present invention have been described above by way of example. However, the scope of protection of the present invention is not limited to the above exemplary embodiments. Any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A sample preparation method for testing the mechanical properties of porous membrane materials, characterized in that, The steps include: determining the porous region contained in the sample to be tested; setting a clamping edge and a stretching edge that surround the porous region without holes at the edge of the porous region; the two clamping edges are arranged opposite each other; the two stretching edges are arranged opposite each other; the clamping edges are used to provide clamping points for the test equipment; the stretching edges are used to provide tensile support; the width of the stretching edge is L, 2d < L < 200d, where d is the maximum horizontal distance between the centers of the two outermost adjacent holes perpendicular to the stretching direction; The length of the clamping edge is W, M+2s<W<M+200s, where M is the depth of the test equipment clamp and s is the maximum vertical distance between the centers of the two outermost adjacent holes along the tensile direction. Furthermore, the dimensions of the two stretching edges and the two clamping edges should be the same.

2. The sample preparation method for testing the mechanical properties of porous membrane materials according to claim 1, characterized in that, 10d < L < 150d.

3. The sample preparation method for testing the mechanical properties of porous membrane materials according to claim 2, characterized in that, 30d < L < 120d.

4. The sample preparation method for testing the mechanical properties of porous membrane materials according to claim 1, characterized in that, M+10s < W < M+150s.

5. The sample preparation method for testing the mechanical properties of porous membrane materials according to claim 4, characterized in that, M+50s < W < M+100s.

6. The sample preparation method for testing the mechanical properties of porous membrane materials according to any one of claims 1 to 5, characterized in that, Setting non-porous clamping and stretching edges at the edge of the pore region includes the following steps: determining that the width of one set of non-porous sides opposite the pore edge in the current sample to be tested is greater than M+2s, and the width of another set of non-porous sides is greater than 2d, and cutting the edge of the sample to be tested to obtain a sample film with a clamping edge length greater than M+2s and a stretching edge width greater than 2d.

7. The sample preparation method for testing the mechanical properties of porous membrane materials according to any one of claims 1 to 5, characterized in that, Setting non-porous clamping and stretching edges at the edge of the pore region includes the following steps: determining that the width of one set of non-porous sides opposite the pore edge in the current sample to be tested is less than or equal to M+2s, and / or the width of another set of non-porous sides is less than or equal to 2d, re-preparing a sample membrane containing the current pore region, wherein the length of the clamping edge in the sample membrane is greater than M+2s, and the width of the stretching edge is greater than 2d.

8. The sample preparation method for testing the mechanical properties of porous membrane materials according to any one of claims 1 to 5, characterized in that, The porous membrane has a pore size of 30–3000 μm.

9. The sample preparation method for testing the mechanical properties of porous membrane materials according to claim 8, characterized in that, The porous membrane has pores that are uniformly or non-uniformly distributed, and the pore sizes of the porous membrane may be the same or different.

10. The sample preparation method for testing the mechanical properties of porous membrane materials according to any one of claims 1 to 5, characterized in that, The porous membrane has a single-layer or multi-layer structure.

11. The sample preparation method for testing the mechanical properties of porous membrane materials according to claim 10, characterized in that, The porous membrane has a 1-10 layer structure; And / or, the thickness of the porous membrane is 100 nm to 200 μm.

12. The sample preparation method for testing the mechanical properties of porous membrane materials according to any one of claims 1 to 5, characterized in that, The porous membrane is made of metal, metal oxide, or polymer.

13. The sample preparation method for testing the mechanical properties of porous membrane materials according to claim 12, characterized in that, The metal is one or more of copper, gold, silver, aluminum, lead, titanium, cadmium, zinc, platinum, indium, and selenium.

14. A sample for testing the mechanical properties of porous membrane materials prepared by the method according to any one of claims 1-13, the sample comprising a pore region and a clamping edge and a stretching edge disposed at the edge of the pore region, the clamping edge being used to provide a clamping point for the testing equipment, and the stretching edge being used to provide tensile support to prevent stress concentration; the width of the stretching edge is L, 2d < L < 200d, where d is the maximum horizontal distance between the centers of the two outermost adjacent pores perpendicular to the stretching direction, and the length of the clamping edge is W, M+2s < W < M+200s, wherein... M is the depth of the test equipment fixture, and s is the maximum vertical distance between the centers of the two outermost adjacent holes along the tensile direction.

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