Polysilsesquioxane / polyetheretherketone composite membrane, preparation method thereof and application of polysilsesquioxane / polyetheretherketone composite membrane in organic mixed solvent separation

Abstract

The invention discloses a polysilsesquioxane / polyether-ether-ketone composite membrane, a preparation method thereof and application of the polysilsesquioxane / polyether-ether-ketone composite membrane in organic mixed solvent separation, and aims to solve the problem of large-area deposition of a defect-free polysilsesquioxane hybrid membrane on a polymer substrate in the prior art. According to the present invention, the 1, 2-bis (triethoxysilyl) ethane polysilsesquioxane precursor is adopted as the raw material to prepare the membrane material, the new membrane preparation method is provided, the processing process is designed and optimized from the aspects of the simplicity and convenience of the membrane preparation process, the industrialization of the membrane separation technology, the improvement of the membrane preparation efficiency and the like, the membrane preparation efficiency is improved, and the certain separation performance is provided; the method has an excellent effect on separation and recovery of methanol / toluene and methanol / dimethyl carbonate.

Description

Technical Field

[0001] The invention belongs to the technical field of membrane separation, and in particular relates to a polysilsesquioxane / polyetheretherketone composite membrane and a preparation method thereof and application thereof in separation of organic mixed solvents. Background Art

[0002] Toluene is a versatile organic solvent widely used in the petroleum and chemical industries, such as paints, rubber, glue silicone sealants, inks, coatings, disinfectants, and leather tanning agents. However, in the industrial production process of toluene (for example, the alkylation reaction of benzene with methanol), the product stream contains a mixture of methanol and toluene, so how to effectively separate methanol / toluene is very important. Dimethyl carbonate (DMC) is a green solvent that combines cleanliness and safety. It is a fuel additive and chemical raw material that can replace phosgene and other harmful substances. Since methanol (MeOH) can produce dimethyl carbonate, efficient separation of azeotropes is essential for the development of dimethyl carbonate. The recovery of organic solvents, including methanol, can provide immediate cost savings and huge environmental benefits for many chemical manufacturing companies. However, many organic-organic mixtures produce azeotropic or near-boiling mixtures that cannot always be easily recovered by conventional distillation. On this basis, the development of an economical and effective separation technology is crucial for the separation of organic solvents.

[0003] Polyetheretherketone (Peek) is composed of repeated 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 known for its high operating temperature and chemical resistance. Its inherent properties are widely used in the synthesis of various separation membranes, especially under harsh conditions. As an ultrafiltration membrane, Peek needs to reduce the pore size of its membrane surface to perform pervaporation separation of organic mixed solvents.

[0004] In recent decades, a variety of microporous materials, including polymers, inorganics, and organic-inorganic hybrid materials, have been extensively studied to obtain high-performance membranes for organic mixed solvent separation. Among them, polysilsesquioxane hybrid membranes, which are composed of organic bridging groups covalently bonded to two silicon atoms, dominate the research on silicon hybrid materials for PV and VP processes. This is mainly due to the amazing thermal and chemical stability, adjustable pore size and affinity, and superior peroxide selectivity of the polysilsesquioxane network structure. These ideal properties originate from the uniform incorporation of different organic bridges in the polysilsesquioxane network through covalent bonds. Polysilsesquioxane has been proven to be a good precursor for the preparation of silicon-based organic-inorganic hybrid membranes. However, large-area deposition of defect-free polysilsesquioxane hybrid membranes on polymer substrates has always been a great challenge.

[0005] All polysilsesquioxane hybrid membranes are prepared on inorganic supports, such as porous Al2O3 supports, with pore sizes of about 200-1000nm. The cost of these ceramic membranes is always higher than that of polymer-based membranes. Therefore, polysilsesquioxane-Al2O3 membranes with complex preparation processes and high costs may not be suitable for large-scale industrial use. In order to overcome this potential disadvantage, and also to realize the industrialization of membrane separation technology as soon as possible, improve membrane preparation efficiency, and shorten membrane preparation time, large-area deposition of defect-free polysilsesquioxane hybrid membranes on existing polymer supports is a difficult problem that needs to be solved at present. Summary of the invention

[0006] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

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

[0008] Therefore, the object of the present invention is to overcome the deficiencies in the prior art and provide a polysilsesquioxane / polyetheretherketone composite film.

[0009] In order to solve the above technical problems, the present invention provides the following technical solution: It is composed of a support body, a transition layer and a polymer sol layer;

[0010] Among them, the support material is polyetheretherketone with a pore size of 1 to 100 nm, the transition layer has the function of shrinking the pore size, 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 the polysilsesquioxane / polyetheretherketone composite film.

[0012] In order to solve the above technical problems, the present invention provides the following technical solutions: comprising:

[0013] The ethanol solvent and the polysilsesquioxane precursor are mixed, and after being fully dissolved, deionized water and hydrochloric acid are added in sequence, and a constant temperature water bath is stirred to perform polymerization reaction to obtain a polysilsesquioxane polymer sol;

[0014] The polysilsesquioxane polymer sol is coated on the polyetheretherketone support body forming the transition layer by a doctor blade coating method, so as to obtain a polysilsesquioxane / polyetheretherketone composite film;

[0015] The molar ratio of the polysilsesquioxane precursor: deionized water: 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 method for preparing 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(triethoxyalkyl)methane and 1,8-bis(triethoxyalkyl)octane.

[0017] As a preferred embodiment of the method for preparing the polysilsesquioxane / polyetheretherketone composite film of the present invention, the stirring temperature of the polymerization reaction in the constant temperature water bath is 30-80° C. and the stirring time is 1-5 hours.

[0018] As 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 comprises:

[0019] The aqueous piperazine solution and the organic 1,3,5-benzenetricarboxylic acid chloride solution are subjected to interfacial polymerization reaction on the support, or polydimethylsiloxane or aminosilicone oil is plasma modified on the support.

[0020] As a preferred embodiment of the method for preparing the polysilsesquioxane / polyetheretherketone composite membrane of the present invention, the interfacial polymerization reaction of the aqueous piperazine solution and the organic 1,3,5-benzenetricarboxylic acid chloride solution on the support body comprises:

[0021] After the polyetheretherketone support is fixed, an aqueous piperazine solution is poured onto the surface of the polyetheretherketone support for a stay reaction, and an organic 1,3,5-benzenetricarboxylic acid chloride solution is poured into the support after removing excess liquid on the surface with a roller, and the solution stays for an interfacial polymerization reaction to form a transition layer, wherein the concentration of the aqueous piperazine solution is 0.5-2wt%, the stay time is 1-5min, and the concentration of the organic 1,3,5-benzenetricarboxylic acid chloride solution is 0.01-0.1wt%, and the stay time is 1-5min;

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

[0023] As a preferred embodiment of the method for preparing the polysilsesquioxane / polyetheretherketone composite film of the present invention, the polysilsesquioxane polymer sol is coated on the polyetheretherketone support forming the transition layer by a doctor blade coating method, comprising:

[0024] The polyetheretherketone support forming the transition layer is fixed, polysilsesquioxane polymer sol is dripped onto one end of the support, and a layer of sol is uniformly coated with a scraper to a thickness of 200-500nm. After calcination and drying, a polysilsesquioxane / polyetheretherketone composite film is formed.

[0025] As a preferred solution of the method for preparing the polysilsesquioxane / polyetheretherketone composite film of the present invention, the speed of the uniform coating is 0.5-5 cm / s.

[0026] As a preferred solution of the method for preparing the polysilsesquioxane / polyetheretherketone composite film of the present invention, the calcination and drying is carried out at a temperature of 50 to 200° C. and for a time of 15 to 60 minutes.

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

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

[0029] Beneficial effects of the present invention:

[0030] Aiming at the problem that it is difficult to deposit defect-free polysilsesquioxane hybrid films on polymer substrates over a large area in the prior art, the present invention uses 1,2-bis(triethoxysilyl)ethane as a polysilsesquioxane silicon precursor, forms a transition layer on a polyetheretherketone (Peek) support, and then coats a polysilsesquioxane polymer sol on the transition layer, proposes a new film-making method, changes the sol-gel preparation process, adopts a scraping method to prepare a polysilsesquioxane / polyetheretherketone composite film with a smooth surface and no defects, designs and optimizes the processing technology, improves the film-making efficiency, and has excellent effects in separation and recovery of methanol / toluene and methanol / dimethyl carbonate. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0032] Figure 1 Schematic diagram of the film-making method of the polysilsesquioxane / polyetheretherketone composite film prepared in Example 1 of the present invention.

[0033] Figure 2 Schematic diagram of the membrane separation mechanism of the polysilsesquioxane / polyetheretherketone composite membrane prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0034] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0035] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present 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 term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0037] The raw materials used in the present invention are all commercially available in the art unless otherwise specified, wherein the pore size of the support polyetheretherketone used is 50 nm.

[0038] Example 1

[0039] Reference Figure 1 Flow chart, this embodiment provides a method for preparing a composite film using polyetheretherketone (Peek) as a support, the structural formula of the 1,2-bis(triethoxysilyl)ethanesilane (BTESE) precursor used is shown in Formula I,

[0040]

[0041] The specific steps are:

[0042] 1) Preparation of composite silica polymer sol:

[0043] 1,2-bis(triethoxysilyl)ethanesilane: deionized water: hydrochloric acid = 1:60:0.2;

[0044] 5.93 g of ethanol solution and 3.05 g of deionized water were mixed, and after being fully dissolved, 0.02 g of hydrochloric acid and 1 g of polysilsesquioxane precursor were added in sequence, and the mixture was stirred in a constant temperature water bath at 40° C. for 2 h for polymerization reaction to obtain a composite silica polymer sol (BTESE sol) with a mass fraction of 10 wt %;

[0045] 2) Preparation of transition layer:

[0046] 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%;

[0047] 0.01 g of 1,3,5-benzenetricarboxylic acid chloride and 20 g of n-hexane were mixed and stirred at room temperature until they were completely dissolved to obtain an organic phase 1,3,5-benzenetricarboxylic acid chloride solution with a mass fraction of 0.05 wt%.

[0048] The polyetheretherketone (Peek) support is fixed on the membrane assembly of the interfacial polymerization (a conventional container for fixing the membrane), and the aqueous piperazine solution (1wt%) is poured into the membrane assembly for a residence time of 3 minutes, and then the excess liquid is removed on the surface of the support with a roller, and then the organic phase 1,3,5-benzenetricarboxylic acid chloride solution (0.05wt%) is poured into the membrane assembly for a residence time of 5 minutes, thereby completing the interfacial polymerization reaction to form a transition layer;

[0049] 3) Preparation of polysilsesquioxane / polyetheretherketone (Peek) film:

[0050] The polysilsesquioxane sol solution is loaded on the surface of the support body forming the transition layer by scraping. Specifically, the Peek support body is fixed on the glass plate with tape, 200 μL of BTESE sol (10 wt%) is dropped onto one end of the support body, and then a scraper is used to scrape a layer at a speed of 2 cm / s with a thickness of about 300 nm. The Peek support body after scraping is calcined and dried at 120°C for 25 minutes to obtain a polysilsesquioxane / polyetheretherketone silicone composite film with polyetheretherketone (Peek) as the support body.

[0051] Example 2

[0052] The difference between this comparative example and Example 1 is that the transition layer in the preparation process is adjusted to polydimethylsiloxane (PDMS) for oxygen plasma modification, the modification pressure is set to 20Pa, the power is 200W, and the time is 120s. The other process parameters are the same as those in Example 1, and the polysilsesquioxane / polyetheretherketone composite film of this example is obtained.

[0053] Example 3

[0054] The difference between this comparative example and Example 1 is that the transition layer in the preparation process is adjusted to amino silicone oil for plasma modification, oxygen plasma modification is performed, the modification pressure is set to 20 Pa, the power is 200 W, and the time is 120 s. The other process parameters are the same as those in Example 1, and the polysilsesquioxane / polyetheretherketone composite film of this comparative example is obtained.

[0055] Comparative Example 1

[0056] The difference between this comparative example and Example 1 is that the modification step of the transition layer is omitted, that is, step 2) is omitted, and the remaining steps are referred to Example 1 to obtain the polysilsesquioxane / polyetheretherketone composite film of this comparative example.

[0057] Comparative Example 2

[0058] The difference between this comparative example and Example 1 is that the calcination and drying temperature in step 3) in the preparation process is adjusted to 50° C., and the other process parameters are the same as those in Example 1, to obtain the polysilsesquioxane / polyetheretherketone composite film of this comparative example.

[0059] Split Testing:

[0060] The membranes prepared in Examples 1 to 3 and Comparative Examples 1 and 2 were used for methanol / toluene and methanol / dimethyl carbonate solution pervaporation demethanolation, and the inlet pressure was controlled to be 100 KPa and the test temperature was 50° C. The feed liquid composition was: 10% methanol, 90% toluene; 10% methanol, 90% dimethyl carbonate, and the methanol flux and separation factor were measured. The results are shown in Table 1.

[0061] Table 1

[0062]

[0063] As can be seen from Table 1, the change of the transition layer also significantly affects the separation effect of the membrane. Polydimethylsiloxane is plasma modified. Plasma treatment can activate the PDMS surface, improve its hydrophilicity, enhance the interaction of the interface and make the monolayer molecules diffuse more easily to its surface, so that the surface of the PDMS substrate can be modified, and finally the methanol molecules can pass through the membrane in large quantities, increasing the permeation flux of methanol. Amino silicone oil is plasma modified. The amine group in the amino silicone oil can react with BTESE, enhance the hydrophilicity of the membrane, and promote the large amount of methanol to pass through the membrane. The interfacial polymerization method can prepare an ultra-thin polymer layer with nanometer scale, and the pore size of the transition layer and the thickness of the membrane can be adjusted by changing the time of the organic phase, which can better control the size of the membrane, which is conducive to reducing the pore size of the membrane and making the top layer BTESE play a better separation performance. In addition, 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.

[0064] After the polysilsesquioxane sol is coated on the Peek support, different calcination temperatures have a certain influence on the membrane separation performance. Low-temperature calcination will increase the Si-OH group content on the membrane surface and increase the pore size, making it easier for methanol molecules to pass through the membrane, thereby increasing the permeation flux of methanol.

[0065] Modifying the Peek membrane surface with a transition layer can achieve the purpose of reducing the surface pore size. For the modification of the transition layer, we used three different modification methods. The first is to perform interfacial polymerization reaction between the aqueous phase piperazine solution and the organic phase 1,3,5-benzenetricarboxylic acid chloride solution on the Peek membrane surface; the second is to perform plasma modification on the Peek membrane surface with polydimethylsiloxane (PDMS) to react with oxygen ions; the third is to perform plasma modification on the Peek membrane surface with amino silicone oil. The above three methods are used to form a transition layer to reduce the pores on the Peek membrane surface.

[0066] Interfacial polymerization is the process of using two highly reactive monomers or prepolymers (usually polyamines and polyacyl chlorides) to undergo a polymerization reaction at the interface of two immiscible solvents (aqueous phase and organic phase), thereby forming an ultra-thin layer on a porous support. The most common method for preparing composite membranes by interfacial polymerization is to react an aqueous piperazine solution with an organic 1,3,5-benzenetricarboxylic acid chloride solution. Since interfacial polymerization can prepare an ultra-thin polymer layer at the nanoscale, this type of membrane has both high selectivity and permeability at low pressure, and thus has received much attention and importance in the field of membrane separation.

[0067] Example 4

[0068] The difference between this embodiment and embodiment 1 is that the residence time of the organic phase 1,3,5-benzenetricarboxylic acid chloride solution in step 3) of embodiment 1 in the membrane assembly is adjusted to 1 min, 3 min, and 7 min, respectively, and the other process parameters are the same as those in embodiment 1, and different polysilsesquioxane / polyetheretherketone composite membranes of this embodiment are obtained. The membrane performance is tested by referring to the above separation test method and compared with embodiment 1. The results are shown in Table 2.

[0069] Table 2

[0070]

[0071] It can be seen from Table 2 that 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, it can be seen that the separation factor is the largest, which means that the transition layer is fully formed and fills the pores on the Peek surface, allowing the top layer to perform better separation performance; and when the residence time is 1 min and 3 min, although there is a certain separation performance, the separation factor is too low, which means that the residence time is too short, resulting in the formation of a transition layer that cannot completely fill the pores on the Peek surface.

[0072] Example 5

[0073] The difference between this embodiment and embodiment 1 is that the BTESE concentrations in the preparation process are adjusted to 0, 5wt%, 7.5wt%, and 12.5wt%, respectively, and the other process parameters are the same as those in embodiment 1. The polysilsesquioxane / polyetheretherketone composite membrane of this embodiment is obtained, and the membrane performance is tested by referring to the above-mentioned separation test method and compared with embodiment 1. The results are shown in Table 3.

[0074] Table 3

[0075]

[0076] It can be seen from Table 3 that no matter it is a separation system of methanol / toluene or methanol / dimethyl carbonate, the membrane material prepared by Example 1 of the present invention has the best separation selectivity. When the BTESE sol concentration in the membrane preparation process is changed to 7.5wt%, the methanol flux is slightly improved, but the selectivity is greatly reduced. When the BTESE sol concentration is changed to 5wt%, the flux and separation factor are significantly reduced. This is because the BTESE sol concentration is reduced and the pores on the Peek surface with the transition layer cannot be completely filled, resulting in defects in the membrane, so both the flux and the separation factor are reduced.

[0077] In summary, the present invention provides a method for preparing a polysilsesquioxane / polyetheretherketone composite membrane for separation of organic mixed solvents by pervaporation. In view of the problem of large-area deposition of defect-free hybrid silica membranes on polymer substrates, a new membrane making method is proposed from the perspectives of simplicity of membrane making process, industrialization of membrane separation technology and improvement of membrane making efficiency. The processing technology is designed and optimized, the membrane making efficiency is improved and it also has certain separation performance, and it has excellent effect in separation and recovery of methanol / toluene and methanol / dimethyl carbonate.

[0078] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A polysilsesquioxane / polyetheretherketone composite film, characterized in that: It is composed of a support, a transition layer and a polymer sol layer; Among them, the support material is polyetheretherketone with a pore size of 1 to 100 nm, the transition layer has the function of shrinking the pore size, 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.

2. The method for preparing the polysilsesquioxane / polyetheretherketone composite film according to claim 1, characterized in that: include, The ethanol solvent and the polysilsesquioxane precursor are mixed, and after being fully dissolved, deionized water and hydrochloric acid are added in sequence, and a constant temperature water bath is stirred to perform polymerization reaction to obtain a polysilsesquioxane polymer sol; The polysilsesquioxane polymer sol is coated on the polyetheretherketone support body forming the transition layer by a doctor blade coating method, so as to obtain a polysilsesquioxane / polyetheretherketone composite film; The molar ratio of the polysilsesquioxane precursor: deionized water: hydrochloric acid is 1:6-240:0.2-1, and the mass fraction of the polysilsesquioxane polymer sol is 5-10 wt %.

3. The method for preparing the polysilsesquioxane / polyetheretherketone composite film according to claim 2, characterized in that: The polysilsesquioxane precursor includes one of 1,2-bis(triethoxysilyl)ethane, 1,2-bis(triethoxysilyl)ethylene, 1,2-bis(triethoxysilyl)acetylene, 1,2-bis(triethoxyalkyl)methane and 1,8-bis(triethoxyalkyl)octane.

4. The method for preparing the polysilsesquioxane / polyetheretherketone composite film according to claim 2, characterized in that: The stirring temperature of the polymerization reaction in the constant temperature water bath is 30 to 80° C., and the stirring time is 1 to 5 hours.

5. The method for preparing the polysilsesquioxane / polyetheretherketone composite film according to claim 2, characterized in that: The method for forming a transition layer on a polyetheretherketone support comprises: The aqueous piperazine solution and the organic 1,3,5-benzenetricarboxylic acid chloride solution are subjected to interfacial polymerization reaction on the support, or polydimethylsiloxane or aminosilicone oil is plasma modified on the support.

6. The method for preparing the polysilsesquioxane / polyetheretherketone composite film according to claim 5, characterized in that: The method of causing the aqueous piperazine solution and the organic 1,3,5-benzenetricarboxylic acid chloride solution to undergo interfacial polymerization on the support comprises: After the polyetheretherketone support is fixed, an aqueous piperazine solution is poured onto the surface of the polyetheretherketone support for a stay reaction, and an organic 1,3,5-benzenetricarboxylic acid chloride solution is poured into the support after removing excess liquid on the surface with a roller, and the solution stays for an interfacial polymerization reaction to form a transition layer, wherein the concentration of the aqueous piperazine solution is 0.5-2wt%, the stay time is 1-5min, and the concentration of the organic 1,3,5-benzenetricarboxylic acid chloride solution is 0.01-0.1wt%, and the stay time is 1-5min; The plasma modification of polydimethylsiloxane or amino silicone oil on the support is oxygen plasma modification, wherein the pressure of the plasma treatment is 15-25 Pa, the treatment power is 150-250 W, and the treatment time is 60-180 s.

7. The method for preparing a polysilsesquioxane / polyetheretherketone composite film according to claim 2, characterized in that: The polysilsesquioxane polymer sol is coated on a polyetheretherketone support forming a transition layer by a doctor blade coating method, comprising: The polyetheretherketone support forming the transition layer is fixed, polysilsesquioxane polymer sol is dripped onto one end of the support, and a layer of sol is uniformly coated with a scraper to a thickness of 200-500nm. After calcination and drying, a polysilsesquioxane / polyetheretherketone composite film is formed.

8. The method for preparing the polysilsesquioxane / polyetheretherketone composite film according to claim 7, characterized in that: The uniform coating speed is 0.5-5 cm / s.

9. The method for preparing a polysilsesquioxane / polyetheretherketone composite film according to claim 7, characterized in that: The calcination and drying process is performed at a temperature of 50 to 200° C. and for a time of 15 to 60 minutes.

10. Use of the polysilsesquioxane / polyetheretherketone composite membrane prepared by the preparation method according to any one of claims 2 to 9 in separating organic mixed solvents, characterized in that: The polysilsesquioxane / polyetheretherketone composite membrane separates organic mixed solvents by pervaporation, wherein the separation system of the organic mixed solvent includes methanol / toluene and methanol / dimethyl carbonate.

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