A polyimide composite and a method for preparing the same

Abstract

The application provides a polyimide composite material and a preparation method thereof. The polyimide composite material is obtained by mixing a modified layered hydroxide material and polyimide, wherein the modified layered hydroxide material is a PEG-modified layered hydroxide material. The polyimide composite material can effectively improve the H2 / CO2 gas separation efficiency and selectivity, and the preparation method of the polyimide composite material has the advantages of simple process, easy operation and mild reaction conditions.

Description

TECHNICAL FIELD

[0001] The present application relates to a polyimide composite material and a preparation method thereof. BACKGROUND

[0002] With the rapid development of hydrogen fuel cell and other fields, the requirement for hydrogen purity is also getting higher and higher. However, the hydrogen prepared by industry often contains certain impurity gases, such as oxygen, nitrogen, carbon dioxide and the like. How to efficiently remove the impurity gases in hydrogen, especially CO2 gas, is the current research hotspot. The medium separation method is an effective method for removing CO2 impurities in hydrogen, but the preparation process of the reported separation medium materials is complex, the removal efficiency of impurity gases is low, the price is high, and it is difficult to mass production. Adding layered double hydroxide (LDHs) in the preparation process of the separation medium material is an effective method to improve its performance and reduce production cost.

[0003] Layered double hydroxide, also known as hydrotalcite-like compound or anion clay, is a kind of layer columnar compound composed of positively charged metal hydroxide and intercalated exchangeable anions. In recent years, layered hydroxide materials have attracted widespread attention in the fields of gas purification, catalysis, biological imaging and electrode materials due to their low cost, strong stability and adjustable composition. However, the lack of active groups on the layered hydroxide sheet leads to insufficient permeation selectivity, resulting in low efficiency of hydrogen purification. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a polyimide composite material with good permeation performance, high selectivity, simple synthesis method and easy operation.

[0005] To solve the above technical problems, the following technical solutions are adopted in the present application:

[0006] The first object of the present application is to provide a polyimide composite material, which is obtained by mixing a modified layered hydroxide material and a polyimide, wherein the modified layered hydroxide material is a PEG-modified layered hydroxide material.

[0007] Preferably, the mass ratio of the PEG to the layered hydroxide material is 0.01-0.15:1, for example, 0.02:1, 0.03:1, 0.04:1, 0.05:1, 0.06:1, 0.07:1, 0.08:1, 0.09:1, 0.10:1, 0.11:1, 0.12:1, 0.13:1, 0.14:1, etc.

[0008] Further preferably, the mass ratio of the PEG to the layered hydroxide material is 0.03-0.15:1.

[0009] Further preferably, the mass ratio of the PEG to the layered double hydroxide material is 0.03-0.08:1.

[0010] Preferably, the layered double hydroxide material is one or more of Co-Ni layered double hydroxide, Fe-Co layered double hydroxide, Fe-Ni layered double hydroxide.

[0011] Further preferably, the layered double hydroxide material is Co-Ni layered double hydroxide.

[0012] Preferably, the mass ratio of the modified layered double hydroxide material to the polyimide is 0.2-0.8:1, such as 0.3:1, 0.35:1, 0.4:1, 0.45:1, 0.5:1, 0.55:1, 0.6:1, 0.65:1, 0.7:1, 0.75:1, etc.

[0013] Further preferably, the mass ratio of the modified layered double hydroxide material to the polyimide is 0.2-0.6:1.

[0014] Further preferably, the mass ratio of the modified layered double hydroxide material to the polyimide is 0.2-0.5:1.

[0015] Preferably, the polyimide composite material is in the form of a film.

[0016] Further preferably, the thickness of the polyimide composite material in the form of a film is 60-100 μm, such as 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, etc.

[0017] A second object of the present application is to provide a method for preparing the polyimide composite material according to any one of the above, characterized in that it comprises the following steps:

[0018] (1) subjecting a layered double hydroxide material to a hydrothermal treatment in the presence of a first solvent and PEG to obtain a modified layered double hydroxide material;

[0019] (2) mixing the modified layered double hydroxide material obtained in step (1) with a polyimide in a second solvent and drying to obtain the polyimide composite material.

[0020] Preferably, in step (1), the hydrothermal treatment is performed at 100-180°C (e.g. 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, 165°C, 170°C, 175°C, etc.) for 2-6 hours (e.g. 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, etc.).

[0021] Further preferably, in step (1), the hydrothermal treatment is performed at 120-180°C for 2-4 hours.

[0022] Preferably, in step (1), the reaction system is subjected to ultrasonic stirring for 1-3 hours (e.g. 1.5 hours, 2 hours, 2.5 hours, etc.) before the hydrothermal treatment.

[0023] Further preferably, in step (1), the reaction system is subjected to ultrasonic stirring for 1.5-2.5 hours before the hydrothermal treatment.

[0024] Preferably, in step (1), after the hydrothermal treatment, the product is washed, centrifuged, and dried to obtain the modified layered double hydroxide material.

[0025] Preferably, in step (2), the mixing is performed under ultrasonic stirring for 4-6 hours (e.g. 4.5 hours, 5 hours, 5.5 hours, etc.).

[0026] Further preferably, in step (2), the mixing is performed under ultrasonic stirring for 4-5 hours.

[0027] In the present application, the power of the ultrasonic stirring is controlled to be 150-200W.

[0028] Preferably, in step (2), after the mixing, the system is laid flat and dried at 50-70°C (e.g. 55°C, 60°C, 65°C, etc.) for 40-50 hours (e.g. 41 hours, 42 hours, 43 hours, 44 hours, 45 hours, 46 hours, 47 hours, 48 hours, 49 hours, etc.) to obtain the polyimide composite material in the form of a film.

[0029] Further preferably, the polyimide composite material is obtained after drying at 55-65°C for 45-50 hours.

[0030] Preferably, the first solvent is selected from one or more of methanol, ethanol, and acetone.

[0031] Further preferably, the first solvent is selected from methanol and / or ethanol.

[0032] Preferably, the second solvent is selected from one or more of methanol, ethanol, isopropanol and acetone.

[0033] Further preferably, the second solvent is selected from ethanol and / or isopropanol.

[0034] Preferably, the preparation method further comprises a step of preparing a layered hydroxide material, which comprises: adding ZIF-67 and nickel nitrate hexahydrate in a third solvent, stirring magnetically at 80-100℃ (for example 85℃, 90℃, 95℃, etc.) for 0.5-2 hours (for example 1 hour, 1.5 hours, etc.), and obtaining the layered hydroxide material after washing, centrifugation and drying.

[0035] Further preferably, the stirring is performed magnetically at 85-95℃ for 0.5-1.5 hours.

[0036] Further preferably, the third solvent is selected from ethanol and / or methanol.

[0037] Still further, the third solvent is selected from ethanol.

[0038] Further preferably, the mass ratio of the ZIF-67 to the nickel nitrate hexahydrate is 2-4:1, for example 2.5:1, 3:1, 3.5:1.

[0039] Still further, the mass ratio of the ZIF-67 to the nickel nitrate hexahydrate is 2.5-3.5:1.

[0040] The amount of solvent used in the preparation process of the present application only needs to ensure that the solvent is excessive, and there is no special requirement.

[0041] Compared with the prior art, the present application has the following advantages:

[0042] The polyimide composite material of the present application is obtained by mixing the layered hydroxide modified by PEG with polyimide, and has the advantages of simple operation, simple synthesis route and mild reaction conditions; the polyimide composite material provided by the present application has good permeability, good selectivity and strong stability, and effectively improves the H2 / CO2 gas separation efficiency and selectivity. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 The scanning electron microscope image of the modified layered hydroxide / polyimide composite material prepared in Example 2 of the present application. DETAILED DESCRIPTION

[0044] The application will be further described in connection with the following examples. However, the application is not limited to the following examples. The implementation conditions used in the examples can be further adjusted according to different requirements of specific use, and the implementation conditions not specified are conventional conditions in the industry. The technical features involved in each embodiment of the application can be combined with each other as long as there is no conflict.

[0045] In view of the defects of the prior art, a new modified layered hydroxide / polyimide composite material is urgently needed. After long-term research and a large number of practices, the inventor has come up with the technical solution of the present application. The technical solution, its implementation process and principles will be further explained as follows.

[0046] The application provides a polyimide composite material, which is obtained by mixing a modified layered hydroxide material and a polyimide, wherein the modified layered hydroxide material is a PEG-modified layered hydroxide material.

[0047] The application adopts PEG-modified layered hydroxide to mix with polyimide to obtain a polyimide composite material. The PEG is used to modify LDHs, which increases the number of active groups on the layered hydroxide sheet, effectively enhances the H2 / CO2 gas separation efficiency and selectivity of the polyimide composite material. At the same time, the wettability of the PEG-modified LDHs on the surface of the polyimide is improved, so that the LDHs particles are uniformly arranged on the surface of the polyimide, effectively improving the permeability and structural stability of the polyimide composite material. The process for preparing the polyimide composite material provided by the application is simple, easy to operate and has the advantages of mild reaction conditions, etc., which provides an effective method for preparing a polyimide composite material with excellent performance.

[0048] The application will be further described in connection with the following examples. However, the application is not limited to the following examples. The implementation conditions used in the examples can be further adjusted according to different requirements of specific use, and the implementation conditions not specified are conventional conditions in the industry. The technical features involved in each embodiment of the application can be combined with each other as long as there is no conflict.

[0049] Example 1

[0050] The ZIF-67 and nickel nitrate hexahydrate with a mass ratio of 3:1 were added to an ethanol solution, and stirred magnetically at 90°C for 1 h. After washing, centrifugation and drying, a layered hydroxide LDHs material was obtained. 1 g of the LDHs material was added to an ethanol solution, and 10 mg of PEG was added thereto after uniform stirring. The solution was stirred under ultrasonic power of 180 W for 2 h. The solution was hydrothermally treated at 100°C for 6 h, and then washed, centrifuged and dried to obtain a modified LDHs material. 1 g of the modified LDHs material was added to an ethanol solution, and 1.25 g of a polyimide material was added thereto. The solution was stirred under ultrasonic power of 180 W for 6 h. The solution was poured on a glass plate, and uniformly scraped and coated. The coated glass plate was dried at 60°C for 48 h, and then demolded after cooling to obtain a PEG-modified modified layered hydroxide / polyimide composite film material.

[0051] Example 2

[0052] The ZIF-67 and nickel nitrate hexahydrate with a mass ratio of 3:1 were added to an ethanol solution, and stirred magnetically at 90°C for 1 h. After washing, centrifugation and drying, a layered hydroxide LDHs material was obtained. 1 g of the LDHs material was added to an ethanol solution, and 50 mg of PEG was added thereto after uniform stirring. The solution was stirred under ultrasonic power of 180 W for 2 h. The solution was hydrothermally treated at 150°C for 4 h, and then washed, centrifuged and dried to obtain a modified LDHs material. 1 g of the modified LDHs material was added to an ethanol solution, and 2 g of a polyimide material was added thereto. The solution was stirred under ultrasonic power of 180 W for 4 h. The solution was poured on a glass plate, and uniformly scraped and coated. The coated glass plate was dried at 60°C for 48 h, and then demolded after cooling to obtain a PEG-modified modified layered hydroxide / polyimide composite film material.

[0053] The scanning electron microscope image of the PEG-modified modified layered hydroxide / polyimide composite material obtained in this example is shown in FIG. 2. Figure 1 As can be seen from FIG. 2, the LDHs particles on the composite material obtained in this example are uniformly arranged on the surface of the polyimide. Figure 1 As can be seen from FIG. 2, the LDHs particles on the composite material obtained in this example are uniformly arranged on the surface of the polyimide.

[0054] Example 3

[0055] ZIF-67 and nickel nitrate hexahydrate with a mass ratio of 3:1 were added to an ethanol solution, stirred magnetically at 90°C for 1 h, washed, centrifuged, and dried to obtain layered hydroxide LDHs material. 1 g of the LDHs material was added to a methanol solution, 150 mg of PEG was added thereto after uniform stirring, and ultrasonic stirring was performed at an ultrasonic power of 180 W for 2 h; hydrothermal treatment was performed at 180°C for 2 h, and the material was washed, centrifuged, and dried to obtain modified LDHs material. 1 g of the modified LDHs material was added to an ethanol solution, 5 g of polyimide material was added thereto, and ultrasonic stirring was performed at an ultrasonic power of 180 W for 4 h; the solution was poured onto a glass plate, uniformly scraped, dried at 60°C for 48 h, and demolded after cooling to obtain a PEG-modified modified layered hydroxide / polyimide composite film material.

[0056] Example 4

[0057] ZIF-67 and nickel nitrate hexahydrate with a mass ratio of 3:1 were added to an ethanol solution, stirred magnetically at 90°C for 1 h, washed, centrifuged, and dried to obtain layered hydroxide LDHs material. 1 g of the LDHs material was added to a methanol solution, 150 mg of PEG was added thereto after uniform stirring, and ultrasonic stirring was performed at an ultrasonic power of 180 W for 2 h; hydrothermal treatment was performed at 180°C for 2 h, and the material was washed, centrifuged, and dried to obtain modified LDHs material. 1 g of the modified LDHs material was added to an ethanol solution, 5 g of polyimide material was added thereto, and ultrasonic stirring was performed at an ultrasonic power of 180 W for 4 h; the solution was poured onto a glass plate, uniformly scraped, dried at 60°C for 48 h, and demolded after cooling to obtain a PEG-modified modified layered hydroxide / polyimide composite film material.

[0058] Example 5

[0059] ZIF-67 and nickel nitrate hexahydrate with a mass ratio of 3:1 were added to an ethanol solution, stirred magnetically at 90°C for 1 h, washed, centrifuged, and dried to obtain layered hydroxide LDHs material. 1 g of the LDHs material was added to a methanol solution, 150 mg of PEG was added thereto after uniform stirring, and ultrasonic stirring was performed at an ultrasonic power of 180 W for 2 h; hydrothermal treatment was performed at 180°C for 2 h, and the material was washed, centrifuged, and dried to obtain modified LDHs material. 1 g of the modified LDHs material was added to an ethanol solution, 5 g of polyimide material was added thereto, and ultrasonic stirring was performed at an ultrasonic power of 180 W for 4 h; the solution was poured onto a glass plate, uniformly scraped, dried at 60°C for 48 h, and demolded after cooling to obtain a PEG-modified modified layered hydroxide / polyimide composite film material.

[0060] Example 6

[0061] The ZIF-67 and nickel nitrate hexahydrate with a mass ratio of 3:1 were added to an ethanol solution, and stirred magnetically at 90°C for 1 h. The layered hydroxide LDHs material was obtained by washing, centrifuging and drying. 1 g of the LDHs material was added to an ethanol solution, and 250 mg of PEG was added thereto. The solution was stirred under ultrasonic power of 180 W for 2 h. The modified LDHs material was obtained by hydrothermal treatment at 100°C for 6 h, washing, centrifuging and drying. 1 g of the modified LDHs material was added to an ethanol solution, and 1.25 g of the polyimide material was added thereto. The solution was stirred under ultrasonic power of 180 W for 6 h. The solution was poured on a glass plate, and was evenly scraped and dried at 60°C for 48 h. After cooling, the modified layered hydroxide / polyimide composite film material was obtained by demolding.

[0062] Comparative Example 1

[0063] The ZIF-67 and nickel nitrate hexahydrate with a mass ratio of 3:1 were added to an ethanol solution, and stirred magnetically at 90°C for 1 h. The layered hydroxide LDHs material was obtained by washing, centrifuging and drying. 1 g of the LDHs material was added to an ethanol solution, and 2 g of the polyimide material was added thereto. The solution was stirred under ultrasonic power of 180 W for 4 h. The solution was poured on a glass plate, and was evenly scraped and dried at 60°C for 48 h. After cooling, the layered hydroxide / polyimide composite film material was obtained by demolding.

[0064] Comparative Example 2

[0065] 50 mg of PEG was added to an ethanol solution, and 2 g of the polyimide material was added thereto. The solution was stirred under ultrasonic power of 180 W for 4 h. The solution was poured on a glass plate, and was evenly scraped and dried at 60°C for 48 h. After cooling, the PEG-modified polyimide film material was obtained by demolding.

[0066] The layered hydroxide / polyimide composite materials prepared in Examples 1 to 6 and Comparative Examples 1 and 2 were tested for H2 / CO2 gas separation performance under the conditions of 25°C and 1.8 MPa, and the thickness of the layered hydroxide / polyimide composite material of each of the examples and the comparative examples was 80 μm. The results are shown in Table 1.

[0067] Table 1

[0068]

[0069] As shown in Table 1, the permeation coefficient and selectivity of the PEG modified layered hydroxide / polyimide composite prepared by the present application are significantly better than those of the unmodified layered hydroxide / polyimide composite. In particular, the PEG modified layered hydroxide / polyimide composite prepared in Example 2 of the present application has good permeation performance and selectivity, and significantly improves the H2 / CO2 gas separation efficiency. If the PEG is excessive, the selectivity of the composite remains excellent, but the permeation performance of the material significantly decreases. If the layered hydroxide is discarded and the PEG is directly modified polyimide, the permeation performance and selectivity of the material are both poor.

[0070] The above detailed description of the present application is intended to enable those skilled in the art to understand and implement the present application, and is not intended to limit the protection scope of the present application. Any equivalent changes or modifications made according to the spirit and principle of the present application shall be covered within the protection scope of the present application.

Claims

1. A polyimide composite, characterized by, The polyimide composite is obtained by mixing a modified layered hydroxide material and a polyimide, wherein the mass ratio of the modified layered hydroxide material to the polyimide is 0.2-0.8:1, the modified layered hydroxide material is a PEG-modified layered hydroxide material, and the layered hydroxide material is a Co-Ni layered double hydroxide.

2. The polyimide composite of claim 1, wherein The mass ratio of the PEG to the layered hydroxide material is 0.01-0.15:

1.

3. The polyimide composite of claim 1, wherein The polyimide composite is in the form of a film.

4. A method for producing the polyimide composite according to any one of claims 1 to 3, characterized by, The method comprises the following steps: (1) obtaining a modified layered hydroxide material by hydrothermally treating a layered hydroxide material and PEG in the presence of a first solvent; (2) mixing the modified layered hydroxide material obtained in step (1) and a polyimide in a second solvent, and drying to obtain the polyimide composite.

5. The production method according to claim 4, characterized by, In step (1), the hydrothermal treatment is performed at 100-180°C for 2-6 hours; and / or, in step (1), the reaction system is subjected to ultrasonic stirring for 1-3 hours before the hydrothermal treatment; And / or, in step (1), the modified layered hydroxide material is obtained by washing, centrifuging and drying the product after the hydrothermal treatment.

6. The preparation method according to claim 4, characterized in that, In step (2), the mixing is performed under ultrasonic stirring for 4-6 hours; and / or, in step (2), the polyimide composite in the form of a film is obtained by laying the mixed system flat and drying at 50-70°C for 40-50 hours.

7. The preparation method according to claim 4, characterized in that, The first solvent is selected from one or more of methanol, ethanol and acetone; and / or, the second solvent is selected from one or more of methanol, ethanol, isopropanol and acetone.

8. The preparation method according to claim 4, characterized in that, The method further comprises a step of preparing a layered hydroxide material, which comprises adding ZIF-67 and nickel nitrate hexahydrate in a third solvent, magnetically stirring at 80-100°C for 0.5-2 hours, and washing, centrifuging and drying to obtain the layered hydroxide material.

9. The preparation method according to claim 8, characterized in that, The third solvent is selected from ethanol and / or methanol; And / or, the mass ratio of the ZIF-67 to the nickel nitrate hexahydrate is 2-4:1.

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