Preparation process and application of polyimide nanofiber membrane

Abstract

The invention relates to the technical field of functional modification of polyimide nanofiber membranes, and discloses a preparation process and application of a polyimide nanofiber membrane. The polyimide nanofiber membrane is prepared through an electrostatic spinning method, and a novel organic-inorganic hybrid antistatic component is prepared in the coating process of the polyimide nanofiber membrane. The preparation method comprises the following steps: preparing an organic-inorganic hybrid antistatic component, dispersing the organic-inorganic hybrid antistatic component in absolute ethyl alcohol to obtain an organic-inorganic hybrid antistatic component dispersion liquid, performing surface treatment on a polyimide nanofiber membrane through polydopamine, and soaking the polyimide nanofiber membrane in the organic-inorganic hybrid antistatic component dispersion liquid to prepare the polyimide nanofiber membrane with the antistatic function. The prepared polyimide nanofiber membrane with the antistatic function has excellent antistatic performance and can be applied to functional clothing such as protective clothing, cold protective clothing and knitted clothing.

Description

Technical Field

[0001] The invention relates to the technical field of functional modification of polyimide nanofiber membranes, and in particular to a preparation process and application of polyimide nanofiber membranes. Background Art

[0002] Polyimide fiber has excellent properties such as high and low temperature resistance, flame retardancy, heat insulation and antibacterial properties, and has good spinnability. It is an ideal material for manufacturing various functional clothing (for example, protective clothing, cold-proof clothing, knitted clothing), and is the most suitable high-performance fiber for large-scale promotion in the clothing field.

[0003] Since polyimide molecules have high polarity, low surface tension, poor water absorption, and high surface resistivity (10 15 -10 20 Ω), resulting in poor antistatic performance of polyimide nanofiber membranes. Its textile products are very likely to accumulate static electricity during use, which may lead to problems such as static electric shock, dust absorption, and combustion. Therefore, it is particularly necessary to perform antistatic treatment on polyimide nanofiber membranes.

[0004] At present, the main methods for antistatic treatment of polyimide nanofiber membranes include adding antistatic agents, surface coating and adding conductive fillers, etc. Among them, surface coating has become one of the important means of antistatic modification of fiber membranes due to its simple operation, strong adjustability and ability to retain the original properties of fiber membranes.

[0005] The present invention cites the following references: In 2011, Hubei University published Chen Chao's master's thesis "Synthesis and Preparation of Functional Cage Oligomeric Silsesquioxanes", which disclosed the divinylchloropropyl pentapropyl cage-shaped silsesquioxane [Si8O 12 The synthesis method and chemical structure of (CH=CH2)2(C3H6Cl)(C3H7)5](POSS2); The present application uses divinylchloropropyl pentapropyl cage-shaped silsesquioxane as a raw material when preparing methacrylate-based tetracarboxyl antistatic functional monomers. Summary of the invention

[0006] The present invention utilizes an electrostatic spinning method to prepare a polyimide fiber membrane, and utilizes a newly developed organic-inorganic hybrid antistatic component to perform antistatic modification on the polyimide fiber membrane, thereby obtaining a polyimide nanofiber membrane product with antistatic function, which can be used in functional clothing such as protective clothing, cold-proof clothing, and knitted clothing.

[0007] To achieve the above object, the present invention adopts the following technical scheme: a preparation process of a polyimide nanofiber membrane, comprising the following steps: Step 1: Prepare polyimide nanofiber membrane by electrospinning; Step 2: Based on the acylation reaction mechanism, under the action of an activator and a catalyst, the carbon nanotubes modified with a silane coupling agent KH550 react with a carboxylated antistatic block copolymer to prepare an organic-inorganic hybrid antistatic component, and the organic-inorganic hybrid antistatic component is dispersed in anhydrous ethanol to obtain an organic-inorganic hybrid antistatic component dispersion; The preparation method of the carboxylated antistatic block copolymer is as follows: the polymerization monomer ethylene glycol monovinyl ether and methacrylate tetracarboxylated antistatic functional monomer undergo atom transfer radical polymerization reaction under the joint action of 2-bromoisobutyric acid ethyl ester and cuprous bromide to obtain the copolymer; Step three: firstly subjecting the polyimide nanofiber membrane to surface treatment with polydopamine, then immersing it in an organic-inorganic hybrid antistatic component dispersion, taking it out and drying it, so as to prepare a polyimide nanofiber membrane with antistatic function.

[0008] Furthermore, the preparation process of the polyimide nanofiber membrane is as follows: Dissolve 4,4'-diaminodiphenyl ether in N,N-dimethylformamide, introduce nitrogen for protection, mechanically stir until completely dissolved, then divide pyromellitic anhydride into three equal batches and add them to the solution in sequence, continue stirring and reacting for 5-7 hours, and prepare a polyamic acid solution; The prepared polyamic acid solution was loaded into a syringe, and an initial polyimide nanofiber membrane was prepared by using an electrospinning technique; The initial polyimide nanofiber membrane is placed in a muffle furnace for gradient heating to cause thermal imidization reaction to obtain a polyimide nanofiber membrane.

[0009] Furthermore, the electrospinning machine parameters are set as follows: voltage 15-25 kV, spinning distance 10-20 cm, propulsion speed 0.5-2 mL / h, drum speed 50-150 rpm, temperature 20-30° C., and relative humidity 35-45%.

[0010] Furthermore, the preparation process of the methacrylate tetracarboxyl antistatic functional monomer is as follows: Under the irradiation of a photoinitiator and an ultraviolet lamp, a "thiol-ene" click chemical reaction occurs between the alkenyl functional group in the structure of divinylchloropropylpentapropyl cage-shaped silsesquioxane and the thiol group in the structure of 2-mercaptosuccinic acid, thereby generating a polycarboxylated chloropropylpentapropyl cage-shaped silsesquioxane monomer. Utilizing the nucleophilic substitution mechanism, the chlorine functional group in the structure of the polycarboxylated chloropropyl pentapropyl cage-shaped silsesquioxane monomer undergoes a quaternization reaction with the tertiary amine group in the structure of dimethylaminoethyl methacrylate to generate a methacrylate-based tetracarboxylated antistatic functional monomer, and the molar ratio of the polycarboxylated chloropropyl pentapropyl cage-shaped silsesquioxane monomer to dimethylaminoethyl methacrylate is 1:(1.00-1.04).

[0011] Furthermore, the photoinitiator is one of benzoin dimethyl ether, benzoin ethyl ether or benzoin isopropyl ether.

[0012] Furthermore, the activator is one of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, N,N-dicyclohexylcarbodiimide or N,N'-diisopropylcarbodiimide.

[0013] Furthermore, the catalyst is one of N-hydroxysuccinimide, 4-dimethylaminopyridine or 1-hydroxybenzotriazole.

[0014] Furthermore, the preparation process of the carbon nanotubes modified by the silane coupling agent KH550 is as follows: Firstly, the carbon nanotubes are pretreated with mixed acid to obtain mixed acid oxidized carbon nanotubes, and then the mixed acid oxidized carbon nanotubes are modified with silane coupling agent KH550 to prepare carbon nanotubes modified with silane coupling agent KH550.

[0015] Furthermore, the preparation process of the polydopamine solution is as follows: adding an aqueous ammonia solution to a mixed solution of ethanol and distilled water, mixing well, adding dopamine hydrochloride, and stirring at room temperature for 10-15 hours to obtain a polydopamine solution; The preparation process of the organic-inorganic hybrid antistatic component dispersion liquid is as follows: the organic-inorganic hybrid antistatic component is ultrasonically dispersed in ethanol to form a uniform dispersion liquid, thereby obtaining the organic-inorganic hybrid antistatic component dispersion liquid.

[0016] The polyimide nanofiber membrane prepared according to the above process is used in functional clothing such as protective clothing, cold-proof clothing, and knitted clothing.

[0017] The beneficial effects of the present invention are as follows: The present invention designs and synthesizes a novel carboxyl antistatic block copolymer, and uses the carboxyl antistatic block copolymer to modify the surface of carbon nanotubes to prepare an organic-inorganic hybrid antistatic component; then the organic-inorganic hybrid antistatic component is made into a dispersion and coated on the surface of a polyimide nanofiber membrane prepared by an electrostatic spinning process to prepare a polyimide nanofiber membrane with antistatic function; It is found through experiments that: compared with common polyimide nanofiber membranes, the polyimide nanofiber membrane with antistatic function prepared by the present invention has excellent antistatic performance and can be used in the textile field. DETAILED DESCRIPTION

[0018] In order to avoid the agglomeration of carbon nanotubes in ethanol, the present invention independently develops a carboxylated antistatic block copolymer, which is used to modify the surface of carbon nanotubes so that they can be evenly dispersed in ethanol, and thus can be evenly distributed on the surface of the fiber membrane, thereby achieving the technical goal of organic-inorganic synergistic antistatic and giving the polyimide nanofiber membrane excellent antistatic properties.

[0019] Embodiment 1:

[0020] The preparation of carboxylated antistatic block copolymer comprises the following steps: (1) Preparation of polycarboxylated chloropropyl pentapropyl cage silsesquioxane monomer, the preparation mechanism of which is: under the irradiation of a photoinitiator and an ultraviolet lamp, the alkenyl functional group in the structure of divinyl chloropropyl pentapropyl cage silsesquioxane and the thiol group in the structure of 2-mercaptosuccinic acid undergo a "thiol-ene" click chemistry reaction to prepare the polycarboxylated chloropropyl pentapropyl cage silsesquioxane monomer. The specific experimental steps are as follows: 0.77 g of divinyl chloropropyl pentapropyl cage silsesquioxane, 1.02 g of 2-mercaptosuccinic acid and 20 mL of tetrahydrofuran are added to a 100 mL single-mouth bottle, stirred and mixed evenly, 0.036 g of benzoin dimethyl ether is added, and the mixture is heated under an ultraviolet lamp (UV) for 24 h. 365nm) irradiation, stirring and reacting for 1h, covering the reaction device with a dark cloth during the reaction to prevent ultraviolet light leakage, and removing tetrahydrofuran by rotation after the reaction, and then using dichloromethane and petroleum ether with a volume ratio of 1:10 as mobile phases and 300 mesh silica gel as stationary phase for column chromatography separation, and placing the product in a vacuum drying oven at 60°C to dry to constant weight to obtain a polycarboxylated chloropropyl pentapropyl cage-shaped silsesquioxane monomer; (2) Preparation of methacrylate tetracarboxyl antistatic functional monomer, the preparation mechanism of which is: using the nucleophilic substitution mechanism, the chlorine functional group in the structure of polycarboxyl chloropropyl pentapropyl cage silsesquioxane monomer and the tertiary amine group in the structure of dimethylaminoethyl methacrylate undergo quaternization reaction to prepare methacrylate tetracarboxyl antistatic functional monomer, and the molar ratio of polycarboxyl chloropropyl pentapropyl cage silsesquioxane monomer to dimethylaminoethyl methacrylate is 1:1. The specific experimental steps are as follows: 8g of polycarboxyl chloropropyl pentapropyl cage silsesquioxane monomer and chloroform are added to a reactor under nitrogen protection, mechanically stirred evenly, and then 1.05g of dimethylaminoethyl methacrylate is added. After the addition is completed, the system temperature is raised to 40°C, stirred for 12h, cooled to room temperature, and then the solvent is removed by rotary evaporation, washed, and vacuum dried at 80°C for 8h to prepare methacrylate tetracarboxyl antistatic functional monomer, the chemical formula of which is: ; The nuclear magnetic resonance hydrogen spectrum of the methacrylate tetracarboxyl antistatic functional monomer is characterized as follows: 1 H NMR (CDCl3, 400MHz) δ: 0.58-0.61 (t, 10H), 0.81-0.84 (t, 2H), 0.86-0.95 (m, 19H), 1.40-1.48 (m, 10H), 1.77-1.84 (m, 2H), 1.92 (s, 3H), 2.71- 2.75 (t, 4H), 2.80-2.95 (m, 4H), 3.19 (s, 6H), 3.52-3.56 (t, 2H), 3.79- 3.87 (m, 2H), 4.04-4.07 (t, 2H), 4.39-4.41 (t, 2H), 5.72-5.81 (d, 2H); (3) Preparation of carboxylated antistatic block copolymers. The preparation mechanism is as follows: using ethylene glycol monovinyl ether and methacrylate tetracarboxylated antistatic functional monomers as raw materials, ethyl 2-bromoisobutyrate as initiator, cuprous bromide as catalyst, N,N,N',N'',N''-pentamethyldiethylenetriamine as ligand, the carboxylated antistatic block copolymers were synthesized by ATRP (atom transfer radical polymerization). The specific experimental steps are as follows: Under nitrogen protection, 0.38 g of N,N,N',N'',N''-pentamethyldiethylenetriamine, 0.14 50 g of ethyl 2-bromoisobutyrate, 5 g of ethylene glycol monovinyl ether, 17.31 g of methyl methacrylate tetracarboxyl antistatic functional monomer and 0.11 g of cuprous bromide were added to a four-necked round-bottom flask equipped with a magnetic stirring rotor, a condenser, a thermometer and a nitrogen protection device, 50 mL of N,N-dimethylformamide was added, the reaction mixture was degassed with high-purity nitrogen for 1 h, then the temperature was raised to 130°C, and the mixture was refluxed for 9 h. After cooling to room temperature, it was filtered, washed, and dried in vacuo at 40°C for 12 h to prepare a carboxyl antistatic block copolymer.

[0021] Embodiment 2:

[0022] An organic-inorganic hybrid antistatic component is prepared based on Example 1, comprising the following steps: Step 1: Prepare carbon nanotubes modified with silane coupling agent KH550, and the preparation mechanism is as follows: first pretreat carbon nanotubes with mixed acid to obtain mixed acid oxidized carbon nanotubes, and then modify the mixed acid oxidized carbon nanotubes with silane coupling agent KH550 to prepare carbon nanotubes modified with silane coupling agent KH550. The specific experimental steps are as follows: 1g carbon nanotubes are placed in 100mL mixed acid (the volume ratio of concentrated sulfuric acid to concentrated nitric acid is 3:1), ultrasonically dispersed for 1h, stirred and refluxed in an oil bath at 80°C for 6h, cooled to room temperature, and then washed by high-speed centrifugation (9000r / min, 10min, washed 3 times alternately with anhydrous ethanol / distilled water), and then vacuum dried at 80°C for 5h to obtain mixed acid oxidized carbon nanotubes; 0.1 g of mixed acid oxidized carbon nanotubes was added to 100 mL of distilled water, ultrasonically dispersed for 45 min, 6 mL of an aqueous solution containing 0.001 g of silane coupling agent KH550 was added, a constant temperature oil bath was placed at 75 ° C, heated to reflux for 6 h, the product was filtered, washed, and vacuum dried at 80 ° C for 5 h to prepare carbon nanotubes modified with silane coupling agent KH550; Step 2: Prepare an organic-inorganic hybrid antistatic component. The preparation mechanism is as follows: under the action of 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxysuccinimide, the amino groups in the carbon nanotubes modified by the silane coupling agent KH550 react with the carboxyl groups in the carboxyl antistatic block copolymer to prepare an organic-inorganic hybrid antistatic component. The specific experimental steps are as follows: 1g of antistatic block copolymer and 200 mL of deionized water were added to a conical flask, ultrasonicated for 1 h, then 0.096 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.039 g of N-hydroxysuccinimide were added, ultrasonicated for 2 h, and then 1.4 g of carbon nanotubes modified with silane coupling agent KH550 were added, stirred in an ice bath for 24 h, filtered, washed, and vacuum dried at 60 ° C for 24 h to prepare an organic-inorganic hybrid antistatic component.

[0023] Embodiment three:

[0024] The main raw materials used in the present invention are as follows: Carbon nanotubes were purchased from Guangzhou Hongwu Material Technology Co., Ltd. with the following specifications: diameter 10-30 nm, length 1-2 μm; The preparation of a polyimide nanofiber membrane with antistatic function comprises the following steps: 1.2 g of 4,4'-diaminodiphenyl ether was dissolved in 12.2 mL of N,N-dimethylformamide, nitrogen was introduced for protection, and mechanical stirring was performed until it was completely dissolved. Then, 1.321 g of pyromellitic anhydride was evenly divided into three batches and added to the solution in sequence (with an interval of 30 min between each batch), and the reaction was continued by stirring for 6 hours to prepare a polyamic acid solution with a solid content of 18 wt%; The prepared polyamic acid solution with a solid content of 18wt% was loaded into a 20mL syringe, and the initial polyimide nanofiber membrane was prepared by electrospinning technology. The electrospinning machine parameters were set as follows: voltage 20kV, spinning distance 20cm, spinning needle inner diameter 0.41mm, propulsion speed 1.5mL / h, drum speed 100rpm, copper mesh (100 mesh) coated drum as a collecting device, temperature 25℃, relative humidity 40%; The electrospinning machine was purchased from Shanghai Dongxiang Nanotechnology Co., Ltd., model DXES-1; The initial polyimide nanofiber membrane is placed in a muffle furnace for gradient heating, and is continuously kept at 80°C, 100°C, 200°C, and 300°C for 1 hour to cause thermal imidization reaction, and the polyimide nanofiber membrane is obtained after natural cooling; 0.4 mL of 30 wt% ammonia solution was added to a mixed solution of 100 mL of ethanol and distilled water (the volume ratio of ethanol to distilled water was 3:7), and after mixing, 0.2 g of dopamine hydrochloride was added, and the mixture was stirred at room temperature for 12 h to obtain a polydopamine solution; 10 g of an organic-inorganic hybrid antistatic component was ultrasonically dispersed in 100 mL of ethanol to form a uniform dispersion to obtain an organic-inorganic hybrid antistatic component dispersion; The polyimide nanofiber membrane was washed three times with acetone and distilled water in sequence, and then immersed in the prepared polydopamine solution. After standing for 12 hours, the polyimide nanofiber membrane coated with polydopamine was placed in a vacuum oven at 60°C for 30 minutes for drying. The fiber membrane was then taken out and immersed in an organic-inorganic hybrid antistatic component dispersion. After mechanical stirring for 5 hours, the fiber membrane was vacuum dried at 60°C for 4 hours to prepare a polyimide nanofiber membrane with antistatic function. The application experiment of polyimide nanofiber membrane with antistatic function is as follows: A protective clothing fabric with a "sandwich" structure was prepared by using a polyimide nanofiber membrane with antistatic function as the core barrier layer and woven fabric as the inner and outer layers.

[0025] Comparative Example 1:

[0026] A polyimide nanofiber membrane is different from the third embodiment in that the polydopamine solution and the organic-inorganic hybrid antistatic component dispersion are not used to coat the surface of the polyimide nanofiber membrane, and the rest is the same as the third embodiment.

[0027] Performance Testing:

[0028] According to GB / T 31838.2-2019 "Dielectric and resistive properties of solid insulating materials Part 2: Resistive properties (DC method) Volume resistance and volume resistivity", the surface resistivity of the polyimide nanofiber membrane with antistatic function prepared in Example 3 and the polyimide nanofiber membrane in Comparative Example 1 was measured using a ZC36 high resistance meter at a temperature of 23°C and a relative humidity of 50%, and the test voltage was set to 500V. Before the test, the fiber membrane was placed in an environment of 23°C and a relative humidity of 50% for 24 hours. The specific test results are shown in Table 1;

[0029] From the data in Table 1, it can be concluded that compared with the membrane product prepared in Comparative Example 1, the surface resistivity of the polyimide nanofiber membrane with antistatic function prepared in Example 3 of the present invention is reduced to 3.67×10 6 Ω, reaching the optimal antistatic range (10 6 -10 9), it can be seen that coating the surface of the polyimide nanofiber membrane with an organic-inorganic hybrid antistatic component can significantly improve the antistatic properties of the polyimide nanofiber membrane.

Claims

1. A process for preparing a polyimide nanofiber membrane, characterized in that: The following steps are involved: Step 1: Prepare polyimide nanofiber membrane by electrospinning; Step 2: Based on the acylation reaction mechanism, under the action of an activator and a catalyst, the carbon nanotubes modified with a silane coupling agent KH550 react with a carboxylated antistatic block copolymer to prepare an organic-inorganic hybrid antistatic component, and the organic-inorganic hybrid antistatic component is dispersed in anhydrous ethanol to obtain an organic-inorganic hybrid antistatic component dispersion; The preparation method of the carboxylated antistatic block copolymer is as follows: the polymerization monomer ethylene glycol monovinyl ether and methacrylate tetracarboxylated antistatic functional monomer undergo atom transfer radical polymerization reaction under the joint action of 2-bromoisobutyric acid ethyl ester and cuprous bromide to obtain the copolymer; Step three: firstly subjecting the polyimide nanofiber membrane to surface treatment with polydopamine, then immersing it in an organic-inorganic hybrid antistatic component dispersion, taking it out and drying it, so as to prepare a polyimide nanofiber membrane with antistatic function.

2. The process for preparing a polyimide nanofiber membrane according to claim 1, characterized in that: The preparation process of the polyimide nanofiber membrane is as follows: Dissolve 4,4'-diaminodiphenyl ether in N,N-dimethylformamide, introduce nitrogen for protection, mechanically stir until completely dissolved, then divide pyromellitic anhydride into three equal batches and add them to the solution in sequence, continue stirring and reacting for 5-7 hours, and prepare a polyamic acid solution; The prepared polyamic acid solution was loaded into a syringe, and an initial polyimide nanofiber membrane was prepared by using an electrospinning technique; The initial polyimide nanofiber membrane is placed in a muffle furnace for gradient heating to cause thermal imidization reaction to obtain a polyimide nanofiber membrane.

3. The process for preparing a polyimide nanofiber membrane according to claim 2, characterized in that: The parameters of the electrospinning machine are set as follows: voltage 15-25 kV, spinning distance 10-20 cm, propulsion speed 0.5-2 mL / h, drum speed 50-150 rpm, temperature 20-30° C., and relative humidity 35-45%.

4. The process for preparing a polyimide nanofiber membrane according to claim 1, characterized in that: The preparation process of the methacrylate tetracarboxyl antistatic functional monomer is as follows: Under the irradiation of a photoinitiator and an ultraviolet lamp, a "thiol-ene" click chemical reaction occurs between the alkenyl functional group in the structure of divinyl chloropropyl pentapropyl cage-shaped silsesquioxane and the thiol group in the structure of 2-mercaptosuccinic acid, thereby generating a polycarboxylated chloropropyl pentapropyl cage-shaped silsesquioxane monomer. Utilizing the nucleophilic substitution mechanism, the chlorine functional group in the structure of the polycarboxylated chloropropyl pentapropyl cage-shaped silsesquioxane monomer undergoes a quaternization reaction with the tertiary amine group in the structure of dimethylaminoethyl methacrylate to generate a methacrylate-based tetracarboxylated antistatic functional monomer, and the molar ratio of the polycarboxylated chloropropyl pentapropyl cage-shaped silsesquioxane monomer to dimethylaminoethyl methacrylate is 1:(1.00-1.04).

5. The process for preparing a polyimide nanofiber membrane according to claim 4, characterized in that: The photoinitiator is one of benzoin dimethyl ether, benzoin ethyl ether or benzoin isopropyl ether.

6. The process for preparing a polyimide nanofiber membrane according to claim 1, characterized in that: The activator is one of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, N,N-dicyclohexylcarbodiimide or N,N'-diisopropylcarbodiimide.

7. The process for preparing a polyimide nanofiber membrane according to claim 1, characterized in that: The catalyst is one of N-hydroxysuccinimide, 4-dimethylaminopyridine or 1-hydroxybenzotriazole.

8. The process for preparing a polyimide nanofiber membrane according to claim 1, characterized in that: The preparation process of the carbon nanotubes modified by the silane coupling agent KH550 is as follows: Firstly, the carbon nanotubes are pretreated with mixed acid to obtain mixed acid oxidized carbon nanotubes, and then the mixed acid oxidized carbon nanotubes are modified with silane coupling agent KH550 to prepare carbon nanotubes modified with silane coupling agent KH550.

9. The process for preparing a polyimide nanofiber membrane according to claim 1, characterized in that: The preparation process of the polydopamine solution is as follows: adding an ammonia solution to a mixed solution of ethanol and distilled water, mixing well, adding dopamine hydrochloride, and stirring at room temperature for 10-15 hours to obtain a polydopamine solution; The preparation process of the organic-inorganic hybrid antistatic component dispersion liquid is as follows: the organic-inorganic hybrid antistatic component is ultrasonically dispersed in ethanol to form a uniform dispersion liquid, thereby obtaining the organic-inorganic hybrid antistatic component dispersion liquid.

10. Use of a polyimide nanofiber membrane prepared according to the process according to any one of claims 1 to 9 in functional clothing such as protective clothing, cold-proof clothing, knitted clothing, etc.

Images