An aromatic poly-1,3,4-oxadiazole film material and a method for preparing the same

Abstract

The application relates to an aromatic poly-1,3,4-oxadiazole film material and a preparation method thereof, relates to the technical field of high polymer materials, and solves the problem of poor film flexibility caused by brittle fracture in the graphitization process of the existing POD material. Amino-substituted phthalic acid and substituted succinic anhydride are combined through dehydration to obtain functionalized phthalic acid; the obtained functionalized phthalic acid, p-phthalic acid and hydrazine salt are combined through a polycondensation reaction under the action of fuming sulfuric acid to obtain a POD solution; the POD solution is vacuum-deaerated and filtered, and then is extruded to a coagulation roller through a forming die, and is coagulated through a multistage coagulation bath to obtain a wet film layer; and the obtained wet film is sufficiently washed and dried to obtain the aromatic poly-1,3,4-oxadiazole film material. The application has wide application prospects in the field of high-thermal-conductivity materials, and can be specifically applied to new products such as foldable-screen mobile phones and square batteries.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to an aromatic poly-1,3,4-oxadiazole membrane material and its preparation method. Background Technology

[0002] Aromatic poly-1,3,4-oxadiazole (POD) is a special engineering plastic whose main chain is composed of aromatic heterocyclic oxadiazoles. Due to its tightly stacked rigid framework molecular structure, it possesses excellent heat resistance, flame retardancy, electrical insulation, and mechanical strength, making it widely applicable in numerous fields, including aerospace, electronics, and high-performance fibers. Artificial thermally conductive graphite films, prepared by carbonization and graphitization of POD thin film materials, have advantages such as low cost, regular crystal structure, higher thermal conductivity, and low coefficient of thermal expansion, and have gradually become a research hotspot in recent years. Under high temperatures, the molecular structure of POD undergoes rearrangement and transformation, gradually shifting towards an ordered graphite structure, and ultimately forming a graphite-like layered structure. The resulting graphitized materials have important applications in thermal conductive materials, electrode materials, and high-temperature resistant structural materials.

[0003] However, the rigidity of POD materials during graphitization brings a series of adverse effects. Due to their high hardness and brittleness, stress concentration easily occurs during high-temperature graphitization, leading to cracks or even breakage. Furthermore, the materials are difficult to carbonize using a roll-firing process; currently, only sheet-firing is applicable, resulting in high graphitization costs and poor flexibility in the obtained graphite films, making them unsuitable for applications requiring bending. This not only affects the material's appearance but also reduces its performance and lifespan, increases firing costs, and significantly limits its application range. Therefore, researching and developing novel flexible POD materials to improve material rigidity and meet practical needs is of great significance.

[0004] To achieve better flexibility, combining POD materials with other flexible materials is a common modification method. For example, the Chinese patent document "A Woven Fabric Made of Polyarylene Oxadiazole Filaments and Quartz Fiber Yarn" (Publication No. CN206279302U) discloses a woven fabric formed by interlacing warp and weft yarns to create a mesh. This fabric combines polyarylene oxadiazole filaments and quartz fibers, resulting in high heat resistance and increased flexibility, making it less prone to breakage. While combining POD with other flexible materials can improve the overall flexibility of the material, this method cannot be used as a graphitization raw material, and it cannot avoid the brittle fracture that occurs during the graphitization process of the POD material itself. The material still suffers from problems such as inability to be rolled and the graphite film's poor bending resistance.

[0005] Given the high difficulty in developing flexible POD materials and the inability of traditional composite material approaches to address the problems encountered during graphitization, it is necessary to develop a novel POD material based on chemical molecular design by introducing flexible structural units. Summary of the Invention

[0006] To address the problem of poor membrane flexibility caused by brittle fracture during the graphitization process of existing POD materials, this invention proposes an aromatic poly-1,3,4-oxadiazole membrane material.

[0007] The specific technical solution of the present invention is as follows:

[0008] An aromatic poly-1,3,4-oxadiazole membrane material has the following structural formula:

[0009]

[0010] Where x:y:z = (0.40~1):(0~0.30):(0~0.30), and y and z are not both 0.

[0011] The present invention also provides a method for preparing the above-mentioned aromatic poly-1,3,4-oxadiazole membrane material, comprising the following steps:

[0012] Functionalized phthalic acid is synthesized by dehydration of amino-substituted phthalic acid and substituted succinic anhydride;

[0013] The obtained functionalized phthalic acid, terephthalic acid and hydrazine salt were subjected to a condensation reaction in the presence of fuming sulfuric acid to prepare POD solution;

[0014] The POD solution is degassed and filtered under vacuum, then extruded through a forming die onto a coagulation roller. After coagulation in a multi-stage coagulation bath, a wet film layer is obtained. The obtained wet film is thoroughly washed and dried to obtain an aromatic poly-1,3,4-oxadiazole membrane material.

[0015] Preferably, the amino-substituted phthalic acid is 5-aminoisophthalic acid, 2-aminoterephthalic acid, or a mixture thereof;

[0016] The optional structures of amino-substituted phthalic acid are listed below:

[0017]

[0018] The substituted succinic anhydride is one or a mixture of at least two of butyl succinic anhydride, decyl succinic anhydride, dodecyl succinic anhydride, tetradecyl succinic anhydride, hexadecyl succinic anhydride, octadecyl succinic anhydride, allyl succinic anhydride, nonenyl succinic anhydride, and dodecenyl succinic anhydride.

[0019] The alternative structures for replacing succinic anhydride are listed below:

[0020]

[0021]

[0022] Preferably, in the synthesis of the functionalized phthalic acid, the molar ratio of amino-substituted phthalic acid to substituted succinic anhydride is (0.80–1.30):1.

[0023] Preferably, the functionalized phthalic acid is functionalized isophthalic acid, functionalized terephthalic acid, or a mixture thereof; the molar ratio of the functionalized isophthalic acid, functionalized terephthalic acid, and terephthalic acid is (0-0.30):(0-0.30):(0.40-1);

[0024] The molar ratio of the total amount of the hydrazine salt to the functionalized phthalic acid and terephthalic acid is (1.02–1.10):1.

[0025] Preferably, the mass fraction of SO3 in the fuming sulfuric acid is 5% to 50%.

[0026] Preferably, the solid content of the reaction system for the polycondensation reaction is 4–20 wt.%.

[0027] Preferably, the reaction conditions are as follows: stirring at 60-90°C for 1-2 hours, then continuing to heat to 100-120°C and stirring for 1-3 hours, then adding benzoic acid for end-capping, then heating to 130-150°C and stirring for 0.5-2 hours, and ending the reaction after the benzoic acid has dissolved and the end-capping is complete.

[0028] Preferably, the multi-stage coagulation bath is a three-stage coagulation bath, wherein the three-stage coagulation bath uses dilute sulfuric acid solutions of different mass concentrations, with the first stage having a mass concentration of 35-55 wt.%, the second stage having a mass concentration of 20-30 wt.%, and the third stage having a mass concentration of 5-15 wt.%; and the temperature of the multi-stage coagulation bath is 30-60°C.

[0029] Preferably, the drying process is as follows: first, drying at 90-130°C, and then heat-setting at 200-250°C.

[0030] Compared with the prior art, the specific beneficial effects of the present invention are as follows:

[0031] 1. The POD membrane material provided by this invention utilizes inexpensive and readily available amino-substituted phthalic acid and substituted succinic anhydride to synthesize functionalized phthalic acid through dehydration. The existing POD material polymerization production line can be upgraded to synthesize new POD materials by adding comonomers without the need for additional equipment. By selecting raw materials with different substitution structures, the flexibility of the synthesized series of materials can be flexibly controlled.

[0032] 2. The process of this invention significantly improves the flexibility of the final POD film material, ensuring that the material remains intact and does not break during the subsequent high-temperature graphitization process. Furthermore, the material can be carbonized and graphitized through a roll-to-sintering process (roll-to-sinter), which greatly reduces the heat treatment cost compared to the current sheet-to-sintering process (sheet-to-sinter), with its overall cost not exceeding 60% of mainstream heat dissipation materials such as graphene film and PI film.

[0033] 3. The graphitized material prepared by the present invention has both the excellent thermal conductivity of POD structure (thermal conductivity > 1700 W / (m·K)) and good bending resistance (bending resistance (R1, 180 degrees) ≥ 100,000 times), breaking through the limitation that traditional POD graphite materials cannot be used in application scenarios that require bending.

[0034] This invention has broad application prospects in the field of high thermal conductivity materials, and can be specifically applied to new products such as foldable screen phones and square batteries. Detailed Implementation

[0035] To make the technical solutions of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. It should be noted that the following embodiments are only used to better understand the technical solutions of the present invention and should not be construed as limiting the present invention.

[0036] Example 1.

[0037] (1) Preparation of POD solution: Using 5-aminoisophthalic acid and butyl succinic anhydride as raw materials, 18.1 parts of 5-aminoisophthalic acid, 15.6 parts of butyl succinic anhydride and 189.7 parts of N,N-dimethylformamide were mixed by mass and heated under reflux for 12 hours. The mixture was then poured into water to obtain a white precipitate. The precipitate was washed with water and dried to obtain the corresponding functionalized phthalic acid. In a polymerization reactor, 77.8 parts of terephthalic acid, 16.8 parts of functionalized phthalic acid and 71.3 parts of hydrazine sulfate were added. Then, 20% fuming sulfuric acid was added until the solid content was 10% and the mixture was stirred evenly. The temperature was raised to 85°C and stirred for 2 hours. Then, the temperature was raised to 120°C and stirred for 3 hours. 2.1 parts of benzoic acid were added for end-capping. Then, the temperature was raised to 140°C and stirred for 2 hours to obtain the POD solution.

[0038] (2) Preparation of POD membrane material: The POD solution was vacuum degassed and filtered, extruded through a forming die to a coagulation roller, and then coagulated in a three-stage coagulation bath (the first stage coagulation bath was 40℃, 45wt.% dilute sulfuric acid solution; the second stage coagulation bath was 45℃, 25wt.% dilute sulfuric acid solution; and the third stage coagulation bath was 50℃, 10wt.% dilute sulfuric acid solution) to obtain a wet film layer. After thorough washing, the wet film was dried at 110℃ and then heat-set at 250℃ to obtain the POD film. The film thickness was 120μm, and the thickness after graphitization was 40μm.

[0039] Example 2.

[0040] (1) Preparation of POD solution: Using 2-aminoterephthalic acid and butyl succinic anhydride as raw materials, 18.1 parts of 2-aminoterephthalic acid, 15.6 parts of butyl succinic anhydride and 189.7 parts of N,N-dimethylformamide were mixed by mass and heated under reflux for 12 hours. The mixture was then poured into water to obtain a white precipitate. The precipitate was washed with water and dried to obtain the corresponding functionalized phthalic acid. In a polymerization reactor, 77.8 parts of terephthalic acid, 16.8 parts of functionalized phthalic acid and 71.3 parts of hydrazine sulfate were added. Then, 20% fuming sulfuric acid was added until the solid content was 10% and the mixture was stirred evenly. The temperature was raised to 85°C and stirred for 2 hours. Then, the temperature was raised to 120°C and stirred for 3 hours. 2.1 parts of benzoic acid were added for end-capping. Then, the temperature was raised to 140°C and stirred for 2 hours to obtain the POD solution.

[0041] (2) Preparation of POD membrane material: The POD solution was vacuum degassed and filtered, extruded through a forming die to a coagulation roller, and then coagulated in a three-stage coagulation bath (the first stage coagulation bath was 40℃, 45wt.% dilute sulfuric acid solution; the second stage coagulation bath was 45℃, 25wt.% dilute sulfuric acid solution; and the third stage coagulation bath was 50℃, 10wt.% dilute sulfuric acid solution) to obtain a wet film layer. After thorough washing, the wet film was dried at 110℃ and then heat-set at 250℃ to obtain the POD film. The film thickness was 120μm, and the thickness after graphitization was 40μm.

[0042] Example 3.

[0043] (1) Preparation of POD solution: Using 5-aminoisophthalic acid or 2-aminoterephthalic acid and butyl succinic anhydride as raw materials, 18.1 parts of 5-aminoisophthalic acid or 2-aminoterephthalic acid, 15.6 parts of butyl succinic anhydride and 189.7 parts of N,N-dimethylformamide were mixed by mass, heated under reflux for 12 h, and then poured into water to obtain a white precipitate. The precipitate was washed with water and dried to obtain the corresponding functionalized isophthalic acid or functionalized terephthalic acid.

[0044] In a polymerization reactor, 77.8 parts of terephthalic acid, 8.4 parts of functionalized isophthalic acid, 8.4 parts of functionalized terephthalic acid, and 71.3 parts of hydrazine sulfate were added. Then, 20% fuming sulfuric acid was added until the solid content was 10% and the mixture was stirred evenly. The temperature was raised to 85°C and stirred for 2 hours. Then, the temperature was raised to 120°C and stirred for 3 hours. 2.1 parts of benzoic acid were added for end-capping. Then, the temperature was raised to 140°C and stirred for 2 hours to obtain a POD solution.

[0045] (2) Preparation of POD membrane material: The POD solution was vacuum degassed and filtered, extruded through a forming die to a coagulation roller, and then coagulated in a three-stage coagulation bath (the first stage coagulation bath was 40℃, 45wt.% dilute sulfuric acid solution; the second stage coagulation bath was 45℃, 25wt.% dilute sulfuric acid solution; and the third stage coagulation bath was 50℃, 10wt.% dilute sulfuric acid solution) to obtain a wet film layer. After thorough washing, the wet film was dried at 110℃ and then heat-set at 250℃ to obtain the POD film. The film thickness was 120μm, and the thickness after graphitization was 40μm.

[0046] Example 4.

[0047] (1) Preparation of POD solution: Using 5-aminoisophthalic acid and decylsuccinic anhydride as raw materials, 18.1 parts of 5-aminoisophthalic acid, 24 parts of decylsuccinic anhydride and 189.7 parts of N,N-dimethylformamide were mixed by mass and heated under reflux for 12 hours. The mixture was then poured into water to obtain a white precipitate. The precipitate was washed with water and dried to obtain the corresponding functionalized phthalic acid. In a polymerization reactor, 77.8 parts of terephthalic acid, 21.2 parts of functionalized phthalic acid and 71.3 parts of hydrazine sulfate were added. Then, 20% fuming sulfuric acid was added until the solid content was 10% and the mixture was stirred evenly. The temperature was raised to 85°C and stirred for 2 hours. Then, the temperature was raised to 120°C and stirred for 3 hours. 2.1 parts of benzoic acid were added for end capping. Then, the temperature was raised to 140°C and stirred for 2 hours to obtain the POD solution.

[0048] (2) Preparation of POD membrane material: The POD solution was vacuum degassed and filtered, extruded through a forming die to a coagulation roller, and then coagulated in a three-stage coagulation bath (the first stage coagulation bath was 40℃, 45wt.% dilute sulfuric acid solution; the second stage coagulation bath was 45℃, 25wt.% dilute sulfuric acid solution; and the third stage coagulation bath was 50℃, 10wt.% dilute sulfuric acid solution) to obtain a wet film layer. After thorough washing, the wet film was dried at 110℃ and then heat-set at 250℃ to obtain the POD film. The film thickness was 120μm, and the thickness after graphitization was 40μm.

[0049] Example 5.

[0050] (1) Preparation of POD solution: Using 5-aminoisophthalic acid and dodecyl succinic anhydride as raw materials, 18.1 parts of 5-aminoisophthalic acid, 26.8 parts of dodecyl succinic anhydride and 189.7 parts of N,N-dimethylformamide were mixed by mass and heated under reflux for 12 hours. The mixture was then poured into water to obtain a white precipitate. The precipitate was washed with water and dried to obtain the corresponding functionalized phthalic acid. In a polymerization reactor, 77.8 parts of terephthalic acid, 22.7 parts of functionalized phthalic acid and 71.3 parts of hydrazine sulfate were added. Then, 20% fuming sulfuric acid was added until the solid content was 10% and the mixture was stirred evenly. The temperature was raised to 85°C and stirred for 2 hours. Then, the temperature was raised to 120°C and stirred for 3 hours. 2.1 parts of benzoic acid were added for end-capping. Then, the temperature was raised to 140°C and stirred for 2 hours to obtain the POD solution.

[0051] (2) Preparation of POD membrane material: The POD solution was vacuum degassed and filtered, extruded through a forming die to a coagulation roller, and then coagulated in a three-stage coagulation bath (the first stage coagulation bath was 40℃, 45wt.% dilute sulfuric acid solution; the second stage coagulation bath was 45℃, 25wt.% dilute sulfuric acid solution; and the third stage coagulation bath was 50℃, 10wt.% dilute sulfuric acid solution) to obtain a wet film layer. After thorough washing, the wet film was dried at 110℃ and then heat-set at 250℃ to obtain the POD film. The film thickness was 120μm, and the thickness after graphitization was 40μm.

[0052] Example 6.

[0053] (1) Preparation of POD solution: Using 5-aminoisophthalic acid and tetradecyl succinic anhydride as raw materials, 18.1 parts of 5-aminoisophthalic acid, 29.6 parts of tetradecyl succinic anhydride and 189.7 parts of N,N-dimethylformamide were mixed by mass and heated under reflux for 12 hours. The mixture was then poured into water to obtain a white precipitate. The precipitate was washed with water and dried to obtain the corresponding functionalized phthalic acid. In a polymerization reactor, 77.8 parts of terephthalic acid, 24.2 parts of functionalized phthalic acid and 71.3 parts of hydrazine sulfate were added. Then, 20% fuming sulfuric acid was added until the solid content was 10% and the mixture was stirred evenly. The temperature was raised to 85°C and stirred for 2 hours. Then, the temperature was raised to 120°C and stirred for 3 hours. 2.1 parts of benzoic acid were added for end capping. Then, the temperature was raised to 140°C and stirred for 2 hours to obtain the POD solution.

[0054] (2) Preparation of POD membrane material: The POD solution was vacuum degassed and filtered, extruded through a forming die to a coagulation roller, and then coagulated in a three-stage coagulation bath (the first stage coagulation bath was 40℃, 45wt.% dilute sulfuric acid solution; the second stage coagulation bath was 45℃, 25wt.% dilute sulfuric acid solution; and the third stage coagulation bath was 50℃, 10wt.% dilute sulfuric acid solution) to obtain a wet film layer. After thorough washing, the wet film was dried at 110℃ and then heat-set at 250℃ to obtain the POD film. The film thickness was 120μm, and the thickness after graphitization was 40μm.

[0055] Example 7.

[0056] (1) Preparation of POD solution: Using 5-aminoisophthalic acid and hexadecyl succinic anhydride as raw materials, 18.1 parts of 5-aminoisophthalic acid, 32.5 parts of hexadecyl succinic anhydride and 189.7 parts of N,N-dimethylformamide were mixed by mass and heated under reflux for 12 hours. The mixture was then poured into water to obtain a white precipitate. The precipitate was washed with water and dried to obtain the corresponding functionalized phthalic acid. In a polymerization reactor, 77.8 parts of terephthalic acid, 25.7 parts of functionalized phthalic acid and 71.3 parts of hydrazine sulfate were added. Then, 20% fuming sulfuric acid was added until the solid content was 10% and the mixture was stirred evenly. The temperature was raised to 85°C and stirred for 2 hours. Then, the temperature was raised to 120°C and stirred for 3 hours. 2.1 parts of benzoic acid were added for end-capping. Then, the temperature was raised to 140°C and stirred for 2 hours to obtain the POD solution.

[0057] (2) Preparation of POD membrane material: The POD solution was vacuum degassed and filtered, extruded through a forming die to a coagulation roller, and then coagulated in a three-stage coagulation bath (the first stage coagulation bath was 40℃, 45wt.% dilute sulfuric acid solution; the second stage coagulation bath was 45℃, 25wt.% dilute sulfuric acid solution; and the third stage coagulation bath was 50℃, 10wt.% dilute sulfuric acid solution) to obtain a wet film layer. After thorough washing, the wet film was dried at 110℃ and then heat-set at 250℃ to obtain the POD film. The film thickness was 120μm, and the thickness after graphitization was 40μm.

[0058] Example 8.

[0059] (1) Preparation of POD solution: Using 5-aminoisophthalic acid and octadecyl succinic anhydride as raw materials, 18.1 parts of 5-aminoisophthalic acid, 35.3 parts of octadecyl succinic anhydride and 189.7 parts of N,N-dimethylformamide were mixed by mass and heated under reflux for 12 hours. The mixture was then poured into water to obtain a white precipitate. The precipitate was washed with water and dried to obtain the corresponding functionalized phthalic acid. In a polymerization reactor, 77.8 parts of terephthalic acid, 27.2 parts of functionalized phthalic acid and 71.3 parts of hydrazine sulfate were added. Then, 20% fuming sulfuric acid was added until the solid content was 10% and the mixture was stirred evenly. The temperature was raised to 85°C and stirred for 2 hours. Then, the temperature was raised to 120°C and stirred for 3 hours. 2.1 parts of benzoic acid were added for end-capping. Then, the temperature was raised to 140°C and stirred for 2 hours to obtain the POD solution.

[0060] (2) Preparation of POD membrane material: The POD solution was vacuum degassed and filtered, extruded through a forming die to a coagulation roller, and then coagulated in a three-stage coagulation bath (the first stage coagulation bath was 40℃, 45wt.% dilute sulfuric acid solution; the second stage coagulation bath was 45℃, 25wt.% dilute sulfuric acid solution; and the third stage coagulation bath was 50℃, 10wt.% dilute sulfuric acid solution) to obtain a wet film layer. After thorough washing, the wet film was dried at 110℃ and then heat-set at 250℃ to obtain the POD film. The film thickness was 120μm, and the thickness after graphitization was 40μm.

[0061] Comparative Example 1.

[0062] (1) Preparation of POD solution: In the polymerization reactor, add 86.4 parts of terephthalic acid and 71.3 parts of hydrazine sulfate by mass, then add 20% fuming sulfuric acid until the solid content is 10% and mix evenly. Heat to 85℃ and stir for 2h, then continue to heat to 120℃ and stir for 3h. Add 2.1 parts of benzoic acid to end cap, then heat to 140℃ and stir for 2h to obtain POD solution.

[0063] (2) Preparation of POD membrane material: The POD solution was vacuum degassed and filtered, extruded through a forming die to a coagulation roller, and then coagulated in a three-stage coagulation bath (the first stage coagulation bath was 40℃, 45wt.% dilute sulfuric acid solution; the second stage coagulation bath was 45℃, 25wt.% dilute sulfuric acid solution; and the third stage coagulation bath was 50℃, 10wt.% dilute sulfuric acid solution) to obtain a wet film layer. After thorough washing, the wet film was dried at 110℃ and then heat-set at 250℃ to obtain the POD film. The film thickness was 120μm, and the thickness after graphitization was 40μm.

[0064] Comparative Example 1 uses conventional monomer polymerization without introducing flexible structural units.

[0065] Example of results.

[0066] The physical properties of the POD films and the properties of the prepared graphite films corresponding to Examples 1-8, Comparative Example 1, and commercially available samples were tested, and the test results are shown in Table 1.

[0067] Table 1

[0068]

[0069] As shown in the table above, the POD material prepared using this invention exhibits higher elongation at break and lower tensile strength. Compared to commercially available POD materials, its flexibility is significantly improved, and the flexibility of the synthesized series of novel POD materials is flexibly adjustable. Therefore, the POD material prepared using this invention is suitable for film formation and roll-to-roll processes, which is of great significance in meeting practical needs.

[0070] The graphitized material obtained by this invention has both the excellent thermal conductivity of POD structure (thermal conductivity > 1700 W / (m·K)) and good bending resistance (bending resistance (R1, 180 degrees) ≥ 100,000 times), breaking through the limitation that traditional POD graphite materials cannot be used in application scenarios that require bending, and can be applied to new products such as foldable screen mobile phones and square batteries.

[0071] Furthermore, the raw materials for this invention are readily available, the synthesis is simple, and the production efficiency is high. The technology can be upgraded simply by adding comonomers to existing production lines, without requiring additional equipment investment. It has a significant cost advantage, with its overall cost not exceeding 60% of mainstream heat dissipation materials such as graphene films and PI films, and it has broad application prospects in the field of high thermal conductivity materials.

[0072] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. An aromatic poly-1,3,4-oxadiazole film material, characterized by, The structure is as follows: ， Wherein, R is any one of butyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, allyl, nonenyl, and dodecenyl; x:y:z = (0.40~1):(0~0.30):(0~0.30), and y and z are not both 0.

2. A method for preparing the aromatic poly-1,3,4-oxadiazole membrane material as described in claim 1, characterized in that, Includes the following steps: Functionalized phthalic acid is synthesized by dehydration of amino-substituted phthalic acid and substituted succinic anhydride; The obtained functionalized phthalic acid, terephthalic acid and hydrazine salt were subjected to a condensation reaction in the presence of fuming sulfuric acid to prepare POD solution; The POD solution is degassed and filtered under vacuum, then extruded through a forming die onto a coagulation roller. After coagulation in a multi-stage coagulation bath, a wet film layer is obtained. The obtained wet film is thoroughly washed and dried to obtain an aromatic poly-1,3,4-oxadiazole membrane material.

3. The method for preparing the aromatic poly-1,3,4-oxadiazole membrane material according to claim 2, characterized in that, The amino-substituted phthalic acid is 5-aminoisophthalic acid, 2-aminoterephthalic acid, or a mixture of the two; The substituted succinic anhydride is one or a mixture of at least two of butyl succinic anhydride, decyl succinic anhydride, dodecyl succinic anhydride, tetradecyl succinic anhydride, hexadecyl succinic anhydride, octadecyl succinic anhydride, allyl succinic anhydride, nonenyl succinic anhydride, and dodecenyl succinic anhydride.

4. The method for preparing the aromatic poly-1,3,4-oxadiazole membrane material according to claim 2, characterized in that, The molar ratio of the amino-substituted phthalic acid to the substituted succinic anhydride is (0.80~1.30):

1.

5. The method for preparing the aromatic poly-1,3,4-oxadiazole membrane material according to claim 2, characterized in that, The functionalized phthalic acid is functionalized isophthalic acid, functionalized terephthalic acid, or a mixture of the two; the molar ratio of the functionalized isophthalic acid, functionalized terephthalic acid, and terephthalic acid is (0~0.30):(0~0.30):(0.40~1); The molar ratio of the total amount of the hydrazine salt to the functionalized phthalic acid and terephthalic acid is (1.02~1.10):

1.

6. The method for preparing the aromatic poly-1,3,4-oxadiazole membrane material according to claim 2, characterized in that, The mass fraction of SO3 in the fuming sulfuric acid is 5% to 50%.

7. The method for preparing the aromatic poly-1,3,4-oxadiazole membrane material according to claim 2, characterized in that, The solid content of the reaction system for the polycondensation reaction is 4~20 wt.%.

8. The method for preparing the aromatic poly-1,3,4-oxadiazole membrane material according to claim 2, characterized in that, The reaction conditions are as follows: stirring at 60~90℃ for 1~2h, then continuing to heat to 100~120℃ and stirring for 1~3h, then adding benzoic acid for end-capping, then heating to 130~150℃ and stirring for 0.5~2h, and ending the reaction after the benzoic acid has dissolved and the end-capping is complete.

9. The method for preparing the aromatic poly-1,3,4-oxadiazole membrane material according to claim 2, characterized in that, The multi-stage coagulation bath is a three-stage coagulation bath, which uses dilute sulfuric acid solutions of different mass concentrations. The mass concentration of the first stage is 35~55 wt.%, the mass concentration of the second stage is 20~30 wt.%, and the mass concentration of the third stage is 5~15 wt.%. The temperature of the multi-stage coagulation bath is 30~60℃.

10. The method for preparing the aromatic poly-1,3,4-oxadiazole membrane material according to claim 2, characterized in that, The drying process is as follows: first, the product is dried at 90~130℃, and then heat-set at 200~250℃.

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