A polysilsesquioxane / polyether ether ketone composite membrane, a preparation method thereof and application thereof in organic mixed solvent separation

Abstract

The application discloses a polysilsesquioxane / polyether ether ketone composite film, a preparation method thereof and application of the composite film in separation of organic mixed solvents, and aims at the problem of depositing a defect-free polysilsesquioxane hybrid film on a polymer substrate in a large area. A film material is prepared by taking 1,2-di(triethoxysilyl)ethane polysilsesquioxane precursor as raw material, a new film preparation method is provided, and the processing technology is designed and optimized from the aspects of simplicity of the film preparation technology, industrialization of the film separation technology and improvement of the film preparation efficiency. The film preparation efficiency is improved, and the film also has certain separation performance, and has excellent effects on separation and recovery of methanol / toluene and methanol / dimethyl carbonate.

Description

Technical Field

[0001] This invention belongs to the field of membrane separation technology, specifically relating to a polysilsesquioxane / polyetheretherketone composite membrane, its preparation method, and its application in the separation of organic mixed solvents. Background Technology

[0002] Toluene is a versatile organic solvent widely used in the petroleum and chemical industries, such as in paints, rubber, adhesives, silicone sealants, inks, coatings, disinfectants, and leather tanning agents. However, in the industrial production of toluene (e.g., the alkylation reaction of benzene and methanol), the product stream contains a mixture of methanol and toluene, making efficient methanol / toluene separation crucial. Dimethyl carbonate (DMC) is a clean and safe green solvent, used as a fuel additive and chemical feedstock, and can replace phosgene and other hazardous substances. Since DMC can be produced from methanol (MeOH), efficient separation of azeotropes is essential for its development. The recovery of organic solvents, including methanol, can provide many chemical manufacturing companies with immediate cost savings and significant environmental benefits. However, many organic-organic mixtures produce azeotropic or near-boiling point mixtures that cannot always be easily recovered through conventional distillation. Therefore, developing a cost-effective separation technology is critical for organic solvent separation.

[0003] Polyether ether ketone (PEEK) is composed of repeating phenyl ether and benzophenone units. Due to its inherent structural characteristics, it exhibits strong chemical resistance in irritating solvents. As an aromatic polymer, PEEK is renowned for its high operating temperature and chemical resistance, and its intrinsic properties are widely used in the synthesis of various separation membranes, especially under harsh conditions. As an ultrafiltration membrane, PEEK requires a reduced pore size on its surface for pervaporation separation of mixed organic solvents.

[0004] In recent decades, extensive research has been conducted on various microporous materials, including polymers, inorganic materials, and organic-inorganic hybrids, to obtain high-performance membranes for the separation of organic mixed solvents. Among these, polysiloxane hybrid membranes, composed of organic bridging groups covalently bonded to two silicon atoms, have dominated research on silicon hybrid materials in PV and VP processes. This is mainly due to the remarkable thermal and chemical stability, tunable pore size and affinity, and superior peroxide selectivity of the polysiloxane network structure. These desirable properties stem from the uniform bonding of different organic bridges within the polysiloxane network via covalent bonds. Polysiloxanes have proven to be excellent precursors for the preparation of silicon-based organic-inorganic hybrid membranes. However, the large-area deposition of defect-free polysiloxane hybrid membranes on polymer substrates remains a significant challenge.

[0005] All polysiloxane hybrid membranes are fabricated on inorganic supports, such as porous Al₂O₃ supports, with pore sizes of approximately 200-1000 nm. The cost of these ceramic membranes is consistently higher than that of polymer-based membranes. Therefore, the complex and costly fabrication process of polysiloxane-Al₂O₃ membranes may not be suitable for large-scale industrial applications. To overcome this potential drawback, and to achieve the industrialization of membrane separation processes as soon as possible, improve membrane fabrication efficiency, and shorten fabrication time, the large-area deposition of defect-free polysiloxane hybrid membranes on existing polymer supports is a current challenge that needs to be addressed. Summary of the Invention

[0006] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0007] In view of the problems existing in the above and / or prior art, the present invention is proposed.

[0008] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a polysilsesquioxane / polyetheretherketone composite film.

[0009] To solve the above-mentioned technical problems, the present invention provides the following technical solution: it is composed of a support, a transition layer and a polymer sol layer;

[0010] The support material is polyetheretherketone with a pore size of 1~100nm. The transition layer has a pore size shrinking function. The polymer sol layer material is polysilsesquioxane polymer sol. The transition layer is formed on the support and the polymer sol layer is coated on the surface of the transition layer.

[0011] Another object of the present invention is to provide a method for preparing a polysilsesquioxane / polyetheretherketone composite film.

[0012] To solve the above-mentioned technical problems, the present invention provides the following technical solution: including,

[0013] Ethanol solvent and polysilsesquioxane precursor are mixed and fully dissolved. Deionized water and hydrochloric acid are added sequentially, and the polymerization reaction is carried out by stirring in a constant temperature water bath to obtain polysilsesquioxane polymer sol.

[0014] The polysilsesquioxane polymer sol is coated onto the polyetheretherketone support forming the transition layer using a blade coating method to obtain a polysilsesquioxane / polyetheretherketone composite film;

[0015] The molar ratio of the polysilsesquioxane precursor to deionized water to hydrochloric acid is 1:6~240:0.2~1, and the mass fraction of the polysilsesquioxane polymer sol is 5~10 wt%.

[0016] As a preferred embodiment of the preparation method of the polysilsesquioxane / polyetheretherketone composite film of the present invention, the polysilsesquioxane precursor includes one of 1,2-bis(triethoxysilyl)ethane, 1,2-bis(triethoxysilyl)ethylene, 1,2-bis(triethoxysilyl)acetylene, 1,2-bis(triethoxysilyl)methane, and 1,8-bis(triethoxysilyl)octane.

[0017] As a preferred embodiment of the preparation method of the polysilsesquioxane / polyetheretherketone composite film of the present invention, the stirring temperature for the polymerization reaction in the constant temperature water bath is 30~80℃, and the stirring time is 1~5h.

[0018] In a preferred embodiment of the method for preparing the polysilsesquioxane / polyetheretherketone composite film of the present invention, the method for forming the transition layer on the polyetheretherketone support includes,

[0019] Interfacial polymerization of an aqueous piperazine solution and an organic 1,3,5-benzenetriformyl chloride solution is carried out on a support, or polydimethylsiloxane or amino silicone oil is plasma modified on a support.

[0020] In a preferred embodiment of the method for preparing the polysilsesquioxane / polyetheretherketone composite film of the present invention, the step of causing the aqueous piperazine solution and the organic 1,3,5-benzenetricarboxyl chloride solution to undergo an interfacial polymerization reaction on a support includes,

[0021] After the polyetheretherketone (PEEK) support is fixed, an aqueous piperazine solution is poured onto the surface of the PEEK support and allowed to react. After removing excess liquid from the surface with a roller, an organic 1,3,5-benzotricarboxylic acid chloride solution is poured in and allowed to react at the interface to form a transition layer. The concentration of the aqueous piperazine solution is 0.5-2 wt%, the residence time is 1-5 min, and the concentration of the organic 1,3,5-benzotricarboxylic acid chloride solution is 0.01-0.1 wt%, the residence time is 1-5 min.

[0022] The plasma modification of polydimethylsiloxane or aminosilicone oil on the support is carried out by oxygen plasma modification, wherein the plasma treatment pressure is 15~25Pa, the treatment power is 150~250W, and the treatment time is 60~180s.

[0023] In a preferred embodiment of the method for preparing the polysilsesquioxane / polyetheretherketone composite film of the present invention, the method includes: coating a polysilsesquioxane polymer sol onto a polyetheretherketone support forming a transition layer using a blade coating method, comprising:

[0024] The polyether ether ketone (PEEK) support forming the transition layer is fixed, and polysilsesquioxane polymer sol is dropped onto one end of the support. A layer of sol with a thickness of 200~500 nm is uniformly coated by a scraper. After calcination and drying, a polysilsesquioxane / PEEK composite film is formed.

[0025] In a preferred embodiment of the preparation method of the polysilsesquioxane / polyetheretherketone composite film of the present invention, the uniform coating speed is 0.5~5cm / s.

[0026] In a preferred embodiment of the preparation method of the polysilsesquioxane / polyetheretherketone composite membrane of the present invention, the calcination and drying temperature is 50~200℃ and the time is 15~60min.

[0027] Another object of the present invention is to provide an application of a polysilsesquioxane / polyetheretherketone composite membrane in the separation of organic mixed solvents.

[0028] As a preferred embodiment of the application of the polysilsesquioxane / polyetheretherketone composite membrane of the present invention in the separation of organic mixed solvents, wherein: the polysilsesquioxane / polyetheretherketone composite membrane separates the organic mixed solvents through pervaporation, wherein the separation system of the organic mixed solvents includes methanol / toluene and methanol / dimethyl carbonate.

[0029] Beneficial effects of this invention:

[0030] This invention addresses the problem of existing technologies' difficulty in depositing defect-free polysilicon silsesquioxane hybrid films over large areas on polymer substrates. Using 1,2-bis(triethoxysilyl)ethane as the polysilicon silsesquioxane silicon precursor, a transition layer is formed on a polyether ether ketone (PEEK) support. Then, a polysilicon silsesquioxane polymer sol is coated onto the transition layer, proposing a novel film-forming method. Furthermore, the sol-gel preparation process is modified, employing a blade coating method to prepare a smooth, defect-free polysilicon silsesquioxane / PEEK composite film. The optimized processing technology improves film-forming efficiency, demonstrating excellent performance in the separation and recovery of methanol / toluene and methanol / dimethyl carbonate. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0032] Figure 1 This is a schematic diagram of the film-forming method of the polysilsesquioxane / polyetheretherketone composite film obtained in Example 1 of the present invention.

[0033] Figure 2 This is a schematic diagram of the membrane separation mechanism of the polysilsesquioxane / polyetheretherketone composite membrane prepared in Example 1 of the present invention. Detailed Implementation

[0034] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0035] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0036] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0037] Unless otherwise specified, all raw materials used in this invention are commercially available in the field. Among them, the pore size of the support polyether ether ketone is 50 nm.

[0038] Example 1

[0039] Reference Figure 1 The flowchart illustrates a method for preparing a composite membrane using polyetheretherketone (PEEK) as a support. The structural formula of the 1,2-bis(triethoxysilyl)ethane (BTESE) silicon precursor used is shown in Formula I.

[0040]

[0041] Formula (I);

[0042] The specific steps are as follows:

[0043] 1) Preparation of composite silicon polymer sol:

[0044] 1,2-Di(triethoxysilyl)ethane:deionized water:hydrochloric acid = 1:60:0.2;

[0045] 5.93g of ethanol solution and 3.05g of deionized water were mixed and fully dissolved. Then, 0.02g of hydrochloric acid and 1g of polysilsesquioxane precursor were added in sequence. The mixture was stirred in a constant temperature water bath at 40℃ for 2h to carry out the polymerization reaction, and a composite silicone polymer sol (BTESE sol) with a mass fraction of 10wt% was obtained.

[0046] 2) Preparation of the transition layer:

[0047] 1 g of anhydrous piperazine and 99 g of deionized water were mixed and stirred at room temperature until completely dissolved to obtain an aqueous piperazine solution with a mass fraction of 1 wt%.

[0048] 0.01 g of 1,3,5-benzenetricarboxyl chloride and 20 g of n-hexane were mixed and stirred at room temperature until completely dissolved to obtain an organic phase 1,3,5-benzenetricarboxyl chloride solution with a mass fraction of 0.05 wt%.

[0049] A polyetheretherketone (PEEK) support is fixed on an interfacially polymerized membrane module (a conventional container used to fix the membrane). An aqueous piperazine solution (1 wt%) is poured into the membrane module and held for 3 min. Then, excess liquid is removed from the support surface with a roller. Next, an organic phase 1,3,5-benzenetricarboxyl chloride solution (0.05 wt%) is poured into the membrane module and held for 5 min. This completes the interfacial polymerization reaction and forms a transition layer.

[0050] 3) Preparation of polysilsesquioxane / polyetheretherketone (Peek) membrane:

[0051] The polysilsesquioxane sol solution was loaded onto the surface of the support to form the transition layer using a scraping method. Specifically, the Peek support was fixed to a glass plate with tape, and 200 μL of BTESE sol (10 wt%) was dropped onto one end of the support. Then, a layer of approximately 300 nm thick was scraped uniformly at a speed of 2 cm / s using a scraper. The Peek support was then calcined and dried at 120 °C for 25 min to obtain a polysilsesquioxane / polyetheretherketone organosilicon composite film with polyetheretherketone (Peek) as the support.

[0052] Example 2

[0053] The difference between this comparative example and Example 1 is that the transition layer in the preparation process is modified with oxygen plasma using polydimethylsiloxane (PDMS). The modification pressure is set to 20 Pa, the power to 200 W, and the time to 120 s. All other process parameters are the same as in Example 1, resulting in the polysilsesquioxane / polyetheretherketone composite membrane of this example.

[0054] Example 3

[0055] The difference between this comparative example and Example 1 is that the transition layer in the preparation process was modified with amino silicone oil by plasma, and oxygen plasma was used for modification. The modification pressure was set to 20 Pa, the power to 200 W, and the time to 120 s. All other process parameters were the same as in Example 1, resulting in the polysilsesquioxane / polyetheretherketone composite membrane of this example.

[0056] Comparative Example 1

[0057] The difference between this comparative example and Example 1 is that the modification step of the transition layer is omitted (i.e., step 2 is omitted). The remaining steps are the same as in Example 1, and the polysilsesquioxane / polyetheretherketone composite film of this comparative example is obtained.

[0058] Comparative Example 2

[0059] The difference between this comparative example and Example 1 is that the calcination and drying temperature in step 3) of the preparation process was adjusted to 50°C, while the remaining process parameters were the same as in Example 1, resulting in the polysilsesquioxane / polyetheretherketone composite film of this comparative example.

[0060] Separation test:

[0061] The membranes prepared in Examples 1-3 and Comparative Examples 1 and 2 were used for pervaporation of methanol / toluene and methanol / dimethyl carbonate solutions to remove methanol. The inlet pressure was controlled at 100 kPa and the test temperature was 50 °C. The feed composition was: 10% methanol, 90% toluene; 10% methanol, 90% dimethyl carbonate. The methanol flux and separation factor were measured, and the results are shown in Table 1.

[0062] Table 1

[0063]

[0064] As shown in Table 1, changes in the transition layer significantly affect the membrane separation performance. Plasma modification of polydimethylsiloxane activates the PDMS surface, enhancing its hydrophilicity, strengthening interfacial interactions, and facilitating the diffusion of monolayer molecules to its surface. This modification of the PDMS matrix surface ultimately allows methanol molecules to permeate the membrane in large quantities, increasing the methanol permeation flux. Plasma modification of amino silicone oil allows the amino groups in the amino silicone oil to react with BTESE, enhancing the membrane's hydrophilicity and promoting the permeation of methanol in large quantities. Interfacial polymerization can prepare ultrathin polymer layers with nanoscale dimensions, and the pore size and membrane thickness of the transition layer can be adjusted by changing the time of the organic phase. This allows for better control of the membrane size, which is beneficial for reducing the membrane pore size and enabling the top-layer BTESE to perform better separation. Furthermore, from... Figure 2It can be seen that, due to the adjustment of the pore size, methanol molecules with smaller pore sizes can pass through the membrane, while toluene or dimethyl carbonate molecules with larger pore sizes cannot pass through the membrane.

[0065] After polysilsesquioxane sol is coated onto the Peek support, different calcination temperatures have a certain impact on the membrane separation performance. Low-temperature calcination will increase the content of Si-OH groups on the membrane surface and increase the pore size, making it easier for methanol molecules to pass through the membrane, thereby increasing the methanol permeation flux.

[0066] Modifying the Peek membrane surface with a transition layer can reduce the surface pore size. Three different modification methods were used for this transition layer. First, an interfacial polymerization reaction was carried out on the Peek membrane surface using an aqueous piperazine solution and an organic 1,3,5-benzenetriformyl chloride solution. Second, polydimethylsiloxane (PDMS) was plasma-modified on the Peek membrane surface, reacting with oxygen ions. Finally, amino silicone oil was plasma-modified on the Peek membrane surface. These three methods were used to form a transition layer to reduce the porosity of the Peek membrane surface.

[0067] Interfacial polymerization utilizes the polymerization reaction of two highly reactive monomers or prepolymers (usually polyamines and polyacrylamide chlorides) at the interface of two immiscible solvents (aqueous and organic phases) to form an ultrathin layer on a porous support. The most common method for preparing composite membranes using interfacial polymerization involves reacting an aqueous piperazine solution with an organic 1,3,5-benzenetricarboxylic acid chloride solution. Because interfacial polymerization can produce ultrathin polymeric layers at the nanoscale, these membranes exhibit both high selectivity and permeability at low pressures, making them a highly regarded and important method in the field of membrane separation.

[0068] Example 4

[0069] The difference between this embodiment and Example 1 is that the residence time of the organic phase 1,3,5-benzenetricarboxylic acid chloride solution in the membrane module in step 3) of Example 1 was adjusted to 1 min, 3 min, and 7 min, respectively. All other process parameters were the same as in Example 1. Different polysilsesquioxane / polyetheretherketone composite membranes were obtained in this embodiment. The membrane performance was tested according to the separation test method described above and compared with that of Example 1. The results are shown in Table 2.

[0070] Table 2

[0071]

[0072] As can be seen from Table 2, the residence time of the organic phase is crucial to the pore size of the transition layer of the membrane. When the residence time is 5 min, the separation factor is the largest, which indicates that the transition layer is fully formed and fills the pores on the Peek surface, allowing the top layer to perform better separation. However, when the residence time is 1 min and 3 min, although there is still some separation performance, the separation factor is too low, which indicates that the residence time is too short, resulting in the formation of the transition layer not being able to completely fill the pores on the Peek surface.

[0073] Example 5

[0074] The difference between this embodiment and Example 1 is that the BTESE concentration in the preparation process was adjusted to 0, 5 wt%, 7.5 wt%, and 12.5 wt%, respectively. All other process parameters were the same as in Example 1. The polysilsesquioxane / polyetheretherketone composite membrane of this embodiment was obtained. The membrane performance was tested according to the separation test method described above and compared with that of Example 1. The results are shown in Table 3.

[0075] Table 3

[0076]

[0077] As can be seen from Table 3, regardless of whether it is a methanol / toluene or methanol / dimethyl carbonate separation system, the membrane material prepared in Example 1 of this invention has the best separation selectivity. When the BTESE sol concentration in the membrane preparation process is changed to 7.5 wt%, the methanol flux increases slightly, but the selectivity decreases significantly. When the BTESE sol concentration is changed to 5 wt%, both the flux and the separation factor decrease significantly. This is because the reduced BTESE sol concentration cannot completely fill the pores on the Peek surface with the transition layer, resulting in membrane defects, which leads to a decrease in both flux and separation factor.

[0078] In summary, this invention provides a method for preparing a polysilsesquioxane / polyetheretherketone composite membrane for the separation of organic mixed solvents via pervaporation. Addressing the problem of existing methods involving large-area deposition of defect-free hybrid silica membranes on polymer substrates, this invention proposes a novel membrane preparation method from the perspectives of simplifying the membrane preparation process, industrializing membrane separation technology, and improving membrane preparation efficiency. The optimized processing technology enhances membrane preparation efficiency while also exhibiting certain separation performance, demonstrating excellent results in the separation and recovery of methanol / toluene and methanol / dimethyl carbonate.

[0079] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for producing a polysilsesquioxane / polyether ether ketone composite film, characterized by: Comprising, The ethanol solvent and polysilsesquioxane precursor are mixed, and after being fully dissolved, deionized water and hydrochloric acid are added in sequence, and a polymerization reaction is carried out in a constant-temperature water bath under stirring to obtain a polysilsesquioxane polymer sol; The polysilsesquioxane polymer sol is coated on the polyether ether ketone support forming a transition layer by a doctor blade method to obtain a polysilsesquioxane / polyether ether ketone composite film. The molar ratio of the polysilsesquioxane precursor, deionized water and hydrochloric acid is 1:6-240:0.2-1, and the mass fraction of the polysilsesquioxane polymer sol is 5-10 wt%. The method for forming the transition layer on the polyether ether ketone support comprises, The aqueous piperazine solution and the organic phase 1,3,5-benzene tricarbonyl chloride solution are subjected to interfacial polymerization on the support or the polydimethylsiloxane or amino silicone oil on the support is subjected to oxygen plasma modification.

2. The method for producing a polysilsesquioxane / polyether ether ketone composite film according to claim 1, characterized by: The polysilsesquioxane precursor comprises one of 1,2-bis(triethoxysilyl)ethane, 1,2-bis(triethoxysilyl)ethylene, 1,2-bis(triethoxysilyl)acetylene, 1,2-bis(triethoxysilyl)methane and 1,8-bis(triethoxysilyl)octane.

3. The method for producing a polysilsesquioxane / polyether ether ketone composite film according to claim 1, characterized by: The stirring temperature of the constant-temperature water bath for the polymerization reaction is 30-80°C, and the stirring time is 1-5 h.

4. The method for producing a polysilsesquioxane / polyether ether ketone composite film according to claim 1, characterized by: The interfacial polymerization of the aqueous piperazine solution and the organic phase 1,3,5-benzene tricarbonyl chloride solution on the support comprises, After the polyether ether ketone support is fixed, the aqueous piperazine solution is poured on the surface of the polyether ether ketone support to stay for reaction, the excess liquid on the surface is removed by a roller, and then the organic phase 1,3,5-benzene tricarbonyl chloride solution is poured to stay for interfacial polymerization to form a transition layer, wherein the concentration of the aqueous piperazine solution is 0.5-2 wt%, the staying time is 1-5 min, the concentration of the organic phase 1,3,5-benzene tricarbonyl chloride solution is 0.01-0.1 wt%, and the staying time is 1-5 min. The plasma treatment pressure for the plasma modification of the polydimethylsiloxane or amino silicone oil on the support is 15-25 Pa, the treatment power is 150-250 W, and the treatment time is 60-180 s.

5. The method for producing a polysilsesquioxane / polyether ether ketone composite film according to claim 1, characterized by: The polysilsesquioxane polymer sol is coated on the polyether ether ketone support forming a transition layer by a doctor blade method to obtain a polysilsesquioxane / polyether ether ketone composite film. The polyether ether ketone support forming a transition layer is fixed, the polysilsesquioxane polymer sol is dropped on one end of the support, a doctor blade is used to uniformly coat a layer of sol with a thickness of 200-500 nm at a constant speed, and a polysilsesquioxane / polyether ether ketone composite film is formed after calcination and drying.

6. The method for producing a polysilsesquioxane / polyether ether ketone composite film according to claim 5, characterized by: The speed of the uniform coating is 0.5-5 cm / s.

7. The method for producing a polysilsesquioxane / polyether ether ketone composite film according to claim 5, characterized by: The temperature of the calcination and drying is 50-200°C, and the time is 15-60 min.

8. A polysilsesquioxane / polyether ether ketone composite film, characterized by: The polysilsesquioxane / polyether ether ketone composite film is prepared by the preparation method of any one of claims 1-7, and is composed of a support, a transition layer and a polymer sol layer, the support material is polyether ether ketone, the pore size is 1-100 nm, the polymer sol layer material is a polysilsesquioxane polymer sol, the transition layer is formed on the support, and the polymer sol layer is coated on the surface of the transition layer.

9. The use of the polysilsesquioxane / polyether ether ketone composite film prepared by the preparation method according to any one of claims 1 to 7 in separating organic mixed solvents, characterized in that: The polysilsesquioxane / polyether ether ketone composite membrane separates organic mixed solvents by pervaporation, wherein the separation system of the organic mixed solvents includes methanol / toluene, methanol / dimethyl carbonate.

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