Preparation method and application of trog base carbon molecular sieve membrane

Abstract

The application belongs to the technical field of membrane preparation and application, and discloses a preparation method and application of a trog base-based carbon molecular sieve membrane. On the basis of a fluorine-containing trog base structure, a phenyl ether structure is introduced into a main chain or a side chain of the trog base through a one-step method by a copolymerization or polymerization mode, the pyrolysis behavior of the trog base is optimized, the fluorine-containing functional group is thermally decomposed into various fluorine-containing gases, the pore is removed at the same time, the phenyl ether structure replaces the N decomposition of the original trog base, and carbon dioxide and other oxygen-containing gases are released instead, the pore size structure is regulated, and finally, the carbon molecular sieve membrane has an optimized pore size structure, so that the carbon molecular sieve membrane has high propylene permeability and high propylene / propane selectivity.

Description

Technical Field

[0001] This invention belongs to the field of membrane preparation and application technology, and discloses a method for preparing and applying a Trog base carbon molecular sieve membrane. Background Technology

[0002] Propylene, as a fundamental chemical in the petrochemical and chemical industries, holds immense industrial significance. Separating propylene from propane is a crucial industrial step for obtaining high-purity propylene. However, due to the similar diameters of propylene and propane (propylene: 4.0 Å, propane: 4.3 Å) and their very close critical temperatures (propylene: 365.2 K, propane: 369.9 K), conventional cryogenic distillation processes for propylene / propane separation are extremely energy-intensive. In recent years, membrane separation technology has emerged as a promising alternative, offering potential advantages in terms of energy and economic feasibility.

[0003] Carbon molecular sieve (CMS) membranes, formed by the pyrolysis of polymer membranes, possess high stability and chemical resistance, and exhibit excellent gas separation performance, making them highly promising for gas separation applications. CMS membranes prepared through controllable processes possess a bimodal pore size distribution structure, including interconnected micropores (7–20 Å) providing high gas flux, and ultramicropores (less than 7 Å) enabling sub-nanometer molecular sieving. The molecular structure of the polymer precursor has a dominant influence on the microstructure and gas transport performance of its derived CMS membranes. This structure-performance relationship creates significant opportunities for designing advanced propylene / propane separation systems based on CMS membranes. However, current CMS membrane precursor designs focus on polyimide (PI) polymers, and many types of PI-CMS membranes derived from PI have also demonstrated excellent propylene / propane separation performance.

[0004] However, polyimide polymers suffer from complex design and synthesis, and are difficult to scale up industrially. Compared to polyimides, which require multiple diamines and dianhydrides for synthesis, terrogallic base polymers (TB), which only require one diamine monomer, offer significant advantages in design and synthesis. A simple one-pot method can synthesize the desired terrogallic base polymer. Furthermore, the unique bicyclic bridged hydrazine structure of TB ensures relatively high selectivity for gases such as hydrogen and carbon dioxide during the pyrolysis to form the CMS structure. However, possibly limited by the low propylene permeability of the original TB-CMS membrane, its propylene / propane separation performance has not yet been studied or explored.

[0005] Therefore, optimizing the pyrolysis of Trog base polymers through structural design and developing CMS membranes with high propylene permeability and propylene / propane selectivity is of great significance for the application of Trog bases in propylene / propane separation. This study provides an oxygen- and fluorine-containing Trog base carbon molecular sieve membrane, its preparation method, and its application. Summary of the Invention

[0006] To achieve the above objectives, the Trog base-based carbon molecular sieve membrane provided by the present invention introduces special fluorine-containing and oxygen-containing functional groups into the main chain or side chain of the Trog base polymer. During the pyrolysis process to form the carbon molecular sieve membrane, the fluorine-containing functional groups are removed to create pores, providing additional permeability to the carbon molecular sieve membrane. The oxygen-containing functional group structure reduces the original decomposition of the N-bridged ring of the Trog base, thereby retaining high selectivity, thus producing a carbon molecular sieve membrane with a specific micropore distribution that can efficiently separate propylene and propane.

[0007] The technical solution of this invention: A method for preparing a Trog base-based carbon molecular sieve membrane includes the following steps: (1) Preparation of Trog base precursor: Trog base precursors are Trog base copolymers or Trog base polymers; (1.1) Preparation of Trog base copolymer: In an ice-water bath, diamine monomers Ar1 and Ar2 were added to a dimethoxymethane solution in proportion, and then trifluoroacetic acid was added dropwise; after stirring at 20-30℃ for 48-168 h, ammonia was added to stop the reaction; the obtained product was washed repeatedly with deionized water, dissolved in chloroform, precipitated with methanol, filtered and dried to obtain the Trog base copolymer, which contains the following repeating unit structure: Where m+n is the degree of polymerization of the Trog base; The diamine monomer Ar1 is any one of the following: The diamine monomer Ar2 is any one of the following: Among them, the diamine monomer Ar1 is one of the diamine monomers 2,2'-bis(trifluoromethyl)diaminobiphenyl, 3,3-bis(trifluoromethyl)-[1,1-biphenyl]-4,4-diamine and 4,4′-(hexafluoroisopropylidene)diphenylamine. The diamine monomer Ar2 is an oxygen- or fluorine-containing diamine monomer or an oxygen-only diamine monomer, such as 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2'-bis(4-(3-aminophenoxy)phenyl)hexafluoropropane, 9,9-bis(trifluoromethyl)-9H-xanthene-2,7-diamine (CAS 139291-41-1), and 4-[4-[1-[4-(4-aminophenoxy)phenyl]-2,2,2-trifluoro-1-phenylethyl]phenoxy]aniline (CAS No.). One of 152210-12-3), 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-oxodiphenylamine, and 2,2'-bis[4-(4-aminophenoxyphenyl)]propane.

[0008] Furthermore, the molar ratio of diamine monomer Ar1 to diamine monomer Ar2 is 1:9-9:1.

[0009] Furthermore, the total molar ratio of diamine monomers Ar1 and Ar2 to the molar ratio of dimethoxymethane is 1:4-6; the total molar ratio of diamine monomers Ar1 and Ar2 to the molar ratio of trifluoroacetic acid is 1:20-30; and the molar ratio of ammonia is 1-2 times that of trifluoroacetic acid.

[0010] (1.2) Preparation of Trog base polymer: In an ice-water bath, the diamine monomer Ar2 was added to a dimethoxymethane solution, followed by the dropwise addition of trifluoroacetic acid; after stirring at 20-30℃ for 48-168 h, ammonia was added to stop the reaction; the obtained product was washed repeatedly with deionized water, dissolved in chloroform, precipitated with methanol, filtered and dried to obtain the Trog base copolymer, which contains the following repeating unit structure: Where n is the degree of polymerization of the Trog base; The molar ratio of the diamine monomer Ar2 to the molar ratio of dimethoxymethane is 1:4-6; the molar ratio of the diamine monomer Ar2 to the molar ratio of trifluoroacetic acid is 1:20-30; and the molar ratio of ammonia is 1-2 times that of trifluoroacetic acid.

[0011] (2) Preparation of precursors for Trog base-derived carbon molecular sieve membranes: The prepared Trog base copolymer or Trog base polymer was dissolved in chloroform to obtain a solution with a certain mass fraction. After stirring for a certain time, the casting solution was introduced into a glass petri dish. After complete natural evaporation, it was dried under vacuum to obtain the precursor of Trog base-derived carbon molecular sieve membrane.

[0012] The mass fraction of the solution was 1.0-20.0 wt.%; the stirring time was 12-48 h.

[0013] (3) Trog base-derived carbon molecular sieve membrane: The precursor of the Trog base-derived carbon molecular sieve membrane was placed between two quartz clamps and placed in a tube furnace. Protective gas C was introduced, the temperature was raised and maintained for a certain period of time, and then the temperature was lowered to room temperature to obtain the Trog base-derived carbon molecular sieve membrane.

[0014] Furthermore, in the above steps, the protective gas C is either nitrogen or argon; the heating temperature is 550-800℃, and the holding time is 2-6 h.

[0015] The technical advantages of this invention are as follows: Based on the Trog base structure, oxygen- and fluorine-containing functional groups are introduced into the main chain or side chain through copolymerization or polymerization, optimizing the pyrolysis behavior of the Trog base. Specifically, the fluorine-containing functional groups thermally decompose into various fluorine-containing gases, removing the pore-forming components. Simultaneously, the oxygen-containing functional groups replace the nitrogen in the original Trog base, releasing oxygen-containing gases such as carbon dioxide, thus regulating the pore structure. The resulting carbon molecular sieve membrane has an optimized pore structure, giving it high propylene permeability and high propylene / propane selectivity. Attached Figure Description

[0016] Figure 1 The results of thermogravimetric-mass spectrometry (TGA) are shown in the figure. In the figure, a, b, and c are the results of TGA of Trog base polymer, fluorinated Trog base polymer, and oxygen-fluorinated Trog base polymer, respectively, representing the release of N-containing gas, F-containing gas, and O-containing gas during pyrolysis.

[0017] Figure 2 The results are BET test results for carbon molecular sieve membranes obtained by pyrolysis of Trog base polymers, fluorinated Trog base polymers, and oxygen-fluorinated Trog base polymers, respectively. Detailed Implementation

[0018] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and technical solutions.

[0019] Gas permeability test: The permeability test of the Trog basic carbon molecular sieve membrane in this invention is conducted using the constant volume change pressure method, and the test temperature is 35 ℃.

[0020] Example 1 5 mmol of 4,4'-diaminodiphenyl ether and 5 mol of 4,4′-(hexafluoroisopropylidene)diphenylamine were added to 20 mL of dimethoxymethane solution. 85 mL of trifluoroacetic acid was slowly added dropwise to the system under ice-water bath conditions. The reaction mixture was stirred at 25 °C for 96 h. The reaction was terminated by adding 500 mL of ammonia. The resulting product was washed repeatedly with aqueous solution, dissolved again in chloroform, precipitated again in methanol, filtered, and dried under vacuum at 80 °C to obtain the Trog base copolymer.

[0021] 0.2 g of the obtained Trog base copolymer was added to chloroform solvent to prepare a casting solution with a mass fraction of 2.0 wt.%. After stirring for 48 h, the casting solution was poured into a glass petri dish and allowed to evaporate naturally for 24 h, and then dried under vacuum for 48 h.

[0022] Take approximately 4 cm of the obtained membrane. 2 Place it in a tube furnace, introduce protective gas N2, heat to 550℃ and maintain for 2 hours, then allow it to cool naturally to room temperature to obtain the Trog basic carbon molecular sieve membrane.

[0023] Example 2 5 mmol of 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane and 5 mol of 4,4′-(hexafluoroisopropylidene)diphenylamine were added to 20 mL of dimethoxymethane solution. 85 mL of trifluoroacetic acid was slowly added dropwise to the system under ice-water bath conditions. The reaction mixture was stirred at 25 °C for 96 h, and the reaction was terminated by adding 500 mL of ammonia. The resulting product was washed repeatedly with aqueous solution, dissolved again in chloroform, precipitated again in methanol, filtered, and dried under vacuum at 80 °C to obtain the Trog base copolymer.

[0024] 0.2 g of the obtained Trog base copolymer was added to chloroform solvent to prepare a casting solution with a mass fraction of 2.0 wt.%. After stirring for 48 h, the casting solution was poured into a glass petri dish and allowed to evaporate naturally for 24 h, and then dried under vacuum for 48 h.

[0025] Take approximately 4 cm of the obtained membrane. 2 Place it in a tube furnace, introduce protective gas N2, heat to 550℃ and maintain for 2 hours, then allow it to cool naturally to room temperature to obtain the Trog basic carbon molecular sieve membrane.

[0026] Example 3 10 mmol of 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane was added to 20 mL of dimethoxymethane solution, and 85 mL of trifluoroacetic acid was slowly added dropwise under ice-water bath conditions. The reaction mixture was stirred at 25 °C for 96 h, and the reaction was terminated by adding 500 mL of ammonia. The resulting product was washed repeatedly with aqueous solution, dissolved again in chloroform, precipitated again in methanol, filtered, and dried under vacuum at 80 °C to obtain the Trog base polymer.

[0027] 0.2 g of the obtained polymer was added to chloroform solvent to prepare a casting solution with a mass fraction of 2.0 wt.%. After stirring for 48 h, the casting solution was poured into a glass petri dish and allowed to evaporate naturally for 24 h, and then dried under vacuum for 48 h.

[0028] Take approximately 4 cm of the obtained membrane. 2 Place it in a tube furnace, introduce protective gas N2, heat to 550℃ and maintain for 2 hours, then allow it to cool naturally to room temperature to obtain the Trog basic carbon molecular sieve membrane.

[0029] Example 4 By replacing the 4,4′-(hexafluoroisopropylidene)diphenylamine monomer in Example 2 with 2,2′-bis(trifluoromethyl)diaminobiphenyl, while keeping other steps the same, a Trog basic carbon molecular sieve membrane was prepared.

[0030] Example 5 In Example 2, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane was replaced with 9,9-bis(trifluoromethyl)-9H-xanthon-2,7-diamine, while keeping all other steps the same, to prepare the Trog basic carbon molecular sieve membrane.

[0031] Example 6 In Example 2, 2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane was replaced with 4-[4-[1-[4-(4-aminophenoxy)phenyl]-2,2,2-trifluoro-1-phenylethyl]phenoxy]aniline, while keeping all other steps the same, to prepare the Trog basic carbon molecular sieve membrane.

[0032] Example 7 In Example 2, the molar amount of 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane was replaced with 1 mmol, and the molar amount of 4,4′-(hexafluoroisopropylidene)diphenylamine was replaced with 9 mmol, while keeping other steps the same, to prepare the Trog basic carbon molecular sieve membrane.

[0033] Example 8 In Example 2, the molar amount of 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane was replaced with 2 mmol, and the molar amount of 4,4′-(hexafluoroisopropylidene)diphenylamine was replaced with 8 mmol, while keeping all other steps the same, to prepare the Trog basic carbon molecular sieve membrane.

[0034] Example 9 In Example 2, the molar amount of 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane was replaced with 3 mmol, and the molar amount of 4,4′-(hexafluoroisopropylidene)diphenylamine was replaced with 7 mmol, while keeping other steps the same, to prepare the Trog basic carbon molecular sieve membrane.

[0035] Example 10 In Example 2, the molar amount of 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane was replaced with 4 mmol, and the molar amount of 4,4′-(hexafluoroisopropylidene)diphenylamine was replaced with 6 mmol, while keeping other steps the same, to prepare the Trog basic carbon molecular sieve membrane.

[0036] Example 11 In Example 2, the molar amount of 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane was replaced with 6 mmol, and the molar amount of 4,4′-(hexafluoroisopropylidene)diphenylamine was replaced with 4 mmol, while keeping all other steps the same, to prepare the Trog basic carbon molecular sieve membrane.

[0037] Example 12 In Example 2, the molar amount of 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane was replaced with 7 mmol, and the molar amount of 4,4′-(hexafluoroisopropylidene)diphenylamine was replaced with 3 mmol, while keeping all other steps the same, to prepare the Trog basic carbon molecular sieve membrane.

[0038] Example 13 In Example 2, the molar amount of 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane was replaced with 8 mmol, and the molar amount of 4,4′-(hexafluoroisopropylidene)diphenylamine was replaced with 2 mmol, while keeping all other steps the same, to prepare the Trog basic carbon molecular sieve membrane.

[0039] Example 14 In Example 2, the molar amount of 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane was replaced with 9 mmol, and the molar amount of 4,4′-(hexafluoroisopropylidene)diphenylamine was replaced with 1 mmol, while keeping all other steps the same, to prepare the Trog basic carbon molecular sieve membrane.

[0040] Compare with Example 1 10 mmol of 4,4'-diamino-3,3'-dimethylbiphenyl was added to 20 mL of dimethoxymethane solution, and 85 mL of trifluoroacetic acid was slowly added dropwise under ice-water bath conditions. The reaction mixture was stirred at 25 °C for 96 h, and the reaction was terminated by adding 500 mL of ammonia. The resulting product was washed repeatedly with aqueous solution, dissolved again in chloroform, precipitated again in methanol, filtered, and dried under vacuum at 80 °C to obtain the Trog base polymer.

[0041] 0.2 g of the obtained polymer was added to chloroform solvent to prepare a casting solution with a mass fraction of 2.0 wt.%. After stirring for 48 h, the casting solution was poured into a glass petri dish, allowed to evaporate naturally for 24 h, and then dried under vacuum for 48 h.

[0042] Take approximately 4 cm of the obtained membrane. 2 Place it in a tube furnace, introduce protective gas N2, heat to 550 ℃ and maintain for 2 h, then allow it to cool naturally to room temperature to obtain a carbon molecular sieve membrane.

[0043] Compare with Example 2 10 mmol of 2,2'-bis(4-(3-aminophenoxy)phenyl)hexafluoropropane was added to 20 mL of dimethoxymethane solution. An ice-water bath was then added to the system, followed by the slow addition of 85 mL of trifluoroacetic acid. The reaction mixture was stirred at 25 °C for 96 h, and the reaction was terminated by adding 500 mL of ammonia. The resulting product was washed repeatedly with aqueous solution, dissolved again in chloroform, precipitated again in methanol, filtered, and dried under vacuum at 80 °C to obtain the Trog base polymer.

[0044] 0.2 g of the obtained polymer was added to chloroform solvent to prepare a casting solution with a mass fraction of 2.0 wt.%. After stirring for 48 h, the casting solution was poured into a glass petri dish, allowed to evaporate naturally for 24 h, and then dried under vacuum for 48 h.

[0045] Take approximately 4 cm of the obtained membrane. 2 Place it in a tube furnace, introduce protective gas N2, heat to 550℃ and maintain for 2 hours, then allow it to cool naturally to room temperature to obtain a carbon molecular sieve membrane.

[0046] Compare with Example 3 10 mmol of 4,4'-diaminodiphenyl ether was added to 20 mL of dimethoxymethane solution. An ice-water bath was then added to the system, followed by the slow addition of 85 mL of trifluoroacetic acid. The reaction mixture was stirred at 25 °C for 96 h, and the reaction was terminated by adding 500 mL of ammonia. The resulting product was washed repeatedly with aqueous solution, dissolved again in chloroform, precipitated again in methanol, filtered, and dried under vacuum at 80 °C to obtain the Trog base polymer.

[0047] 0.2 g of the obtained polymer was added to chloroform solvent to prepare a casting solution with a mass fraction of 2.0 wt.%. After stirring for 48 h, the casting solution was poured into a glass petri dish, allowed to evaporate naturally for 24 h, and then dried under vacuum for 48 h.

[0048] Take approximately 4 cm of the obtained membrane. 2 Place it in a tube furnace, introduce protective gas N2, heat to 550℃ and maintain for 2 hours, then allow it to cool naturally to room temperature to obtain a carbon molecular sieve membrane.

[0049] Table 1 shows the gas permeability and selectivity (35°C, 2 Bar) of the carbon molecular sieve membranes prepared in the control example and the example.

[0050] In Table 1, Comparative Example 1 is the original Trog base polymer, without any additional fluorinated or oxygen-containing functional groups; Comparative Example 2 is a fluorinated-oxygen-free Trog base polymer; and Comparative Example 3 is a Trog base polymer prepared from oxygen-only monomers. Example 1 is a semi-fluorinated, semi-oxygenated Trog base copolymer prepared from fluorinated monomers and oxygen-only monomers in a molar ratio of 1:1; Example 2 is a Trog base copolymer prepared from fluorinated monomers and fluorinated-oxygen monomers in a molar ratio of 1:1; Example 3 is a polymer prepared from fluorinated-oxygen monomers; Example 8 is a Trog base copolymer prepared from fluorinated monomers and fluorinated-oxygen monomers in a molar ratio of 8:2; and Example 13 is a Trog base copolymer prepared from fluorinated monomers and fluorinated-oxygen monomers in a molar ratio of 2:8. Characterization results Figure 1 , Figure 2 Together with the actual gas performance test results in Table 1, they illustrate the mechanism by which the types and contents of fluorine-containing and oxygen-containing functional groups in the Trog base precursor regulate and optimize the structure and performance of its derived carbon molecular sieve membrane. Figure 1In contrast to the original Trog base polymer without fluorine or oxygen functional groups in Comparative Example 1, which mainly released HCN and NH3 during thermal decomposition, the fluorine-containing Trog base polymer-derived carbon molecular sieve membrane in Comparative Example 2 exhibited additional fluorine-related gas release during thermal decomposition, resulting in a significant expansion of the bimodal pore structure and an increase in pore volume. The carbon molecular sieve membranes in Comparative Examples 2, 1, 2, 3, 8, and 13, which contain fluorine functional groups, also showed significantly higher gas permeability. The effect of oxygen-containing functional groups on the Trog base-derived carbon molecular sieve membrane was reflected in improved selectivity. The oxygen-only Trog base polymer-derived carbon molecular sieve membrane in Comparative Example 3 showed a significant improvement in selectivity compared to the original Trog base carbon molecular sieve membrane in Comparative Example 1. Furthermore, the introduction of fluorine- and oxygen-containing functional groups into the Trog base can achieve a dual improvement in permeability and selectivity. Figure 1 The results show that the fluorinated functional groups of the fluorinated-oxygen-containing Trog base polymer in Example 3 generate additional fluorinated gases through thermal decomposition, and its oxygen-containing functional groups reduce the release of nitrogen-containing gases such as HCN and NH3 by transforming into additional CO2 and COF3 gases during pyrolysis. As a result, the permeability and selectivity of its derived carbon molecular sieve membrane are improved in both directions.

[0051] Furthermore, compared to the fluorine-containing Trog base polymer-derived carbon molecular sieve membrane of Comparative Example 2 or the oxygen-containing Trog base polymer-derived carbon molecular sieve membrane of Comparative Example 3, the permeability and selectivity of the carbon molecular sieve membrane are simultaneously improved with the gradual introduction of fluorine-containing and oxygen-containing functional groups. This can be demonstrated by the simultaneous improvement of permeability and selectivity of the carbon molecular sieve membranes of Examples 1, 8, 2, 13 and 3.

[0052] Overall, compared with the original Trog base-derived carbon molecular sieve membrane of Control Example 1, the propylene permeability and propylene and propane selectivity of the Trog base-derived carbon molecular sieve membrane gradually increased with the gradual increase of oxygen-containing functional groups and fluorine-containing functional groups, and the performance of Example 3 reached the highest value.

Claims

1. A method for preparing a Trog base-carbon molecular sieve membrane, characterized in that, Includes the following steps: (1) Preparation of Trog base precursor: The preparation of Trog base precursors is the preparation of Trog base copolymers or Trog base polymers; (2) Preparation of precursors for Trog base-derived carbon molecular sieve membranes: The prepared Trog base copolymer or Trog base polymer was dissolved in chloroform to obtain a solution with a certain mass fraction. After stirring for a certain time, the casting solution was introduced into a glass petri dish. After complete natural evaporation, it was dried under vacuum to obtain the precursor of Trog base-derived carbon molecular sieve membrane. (3) Trog base-derived carbon molecular sieve membrane: The precursor of the Trog base-derived carbon molecular sieve membrane was placed between two quartz clamps and placed in a tube furnace. Protective gas C was introduced, the temperature was raised and maintained for a certain period of time, and then the temperature was lowered to room temperature to obtain the Trog base-derived carbon molecular sieve membrane.

2. The preparation method according to claim 1, characterized in that, Preparation of Trog base copolymer: Diamine monomers Ar1 and Ar2 were added to a dimethoxymethane solution in a specific ratio in an ice-water bath, followed by the dropwise addition of trifluoroacetic acid. The mixture was stirred at 20-30°C for 48-168 h, and then ammonia was added to terminate the reaction. The resulting product was washed repeatedly with deionized water, dissolved in chloroform, precipitated with methanol, filtered, and dried to obtain the Trog base copolymer. The Trog base copolymer contains the following repeating unit structure: Where m+n is the degree of polymerization of the Trog base; The diamine monomer Ar1 is one of the diamine monomers 2,2'-bis(trifluoromethyl)diaminobiphenyl, 3,3-bis(trifluoromethyl)-[1,1-biphenyl]-4,4-diamine and 4,4′-(hexafluoroisopropylidene)diphenylamine; The diamine monomer Ar2 is one of 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2'-bis(4-(3-aminophenoxy)phenyl)hexafluoropropane, 9,9-bis(trifluoromethyl)-9H-xanthon-2,7-diamine, 4-[4-[1-[4-(4-aminophenoxy)phenyl]-2,2,2-trifluoro-1-phenylethyl]phenoxy]aniline, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-oxodiphenylamine, and 2,2'-bis[4-(4-aminophenoxyphenyl)]propane.

3. The preparation method according to claim 2, characterized in that, The molar ratio of diamine monomer Ar1 to diamine monomer Ar2 is 1:9-9:1; The total molar ratio of diamine monomers Ar1 and Ar2 to the molar ratio of dimethoxymethane is 1:4-6; the total molar ratio of diamine monomers Ar1 and Ar2 to the molar ratio of trifluoroacetic acid is 1:20-30; and the molar ratio of ammonia is 1-2 times that of trifluoroacetic acid.

4. The preparation method according to claim 1, characterized in that, Preparation of Trog base polymer: Diamine monomer Ar2 was added to a dimethoxymethane solution in an ice-water bath, followed by the dropwise addition of trifluoroacetic acid. The mixture was stirred at 20-30°C for 48-168 h, and then ammonia was added to terminate the reaction. The resulting product was washed repeatedly with deionized water, dissolved in chloroform, precipitated with methanol, filtered, and dried to obtain the Trog base copolymer. The Trog base copolymer contains the following repeating unit structure: Where n is the degree of polymerization of the Trog base; The diamine monomer Ar2 is one of 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2'-bis(4-(3-aminophenoxy)phenyl)hexafluoropropane, 9,9-bis(trifluoromethyl)-9H-xanthon-2,7-diamine, 4-[4-[1-[4-(4-aminophenoxy)phenyl]-2,2,2-trifluoro-1-phenylethyl]phenoxy]aniline, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-oxodiphenylamine, and 2,2'-bis[4-(4-aminophenoxyphenyl)]propane.

5. The preparation method according to claim 4, characterized in that, The molar ratio of the diamine monomer Ar2 to the molar ratio of dimethoxymethane is 1:4-6; the molar ratio of the diamine monomer Ar2 to the molar ratio of trifluoroacetic acid is 1:20-30; and the molar ratio of ammonia is 1-2 times that of trifluoroacetic acid.

6. The preparation method according to any one of claims 1-5, characterized in that, In step (2), the mass fraction of the solution is 1.0-20.0 wt.%; the stirring time is 12-48 h.

7. The preparation method according to any one of claims 1-5, characterized in that, In step (3), the protective gas C is either nitrogen or argon; the heating temperature is 550-800℃ and the holding time is 2-6 h.

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