Flexible thermal insulating organic aerogel and method for its preparation

Abstract

The present application relates to a kind of flexible heat-insulating organic aerogel and its preparation method.The heat-insulating aerogel has nanofiber structure and closed pore structure, and has excellent flexibility, heat-insulating performance and excellent tensile and compression performance.The aerogel can be prepared by coating oil-in-oil emulsion on the surface of fabric and gelatinizing, including the following steps: non-polar oil is added to polar solvent containing crystalline polymer and stabilizer to prepare oil-in-oil emulsion, and the emulsion is immersed on the fabric, and after gelatinizing, the flexible heat-insulating organic aerogel can be prepared by drying.The aerogel has the characteristics of good flexibility, low thermal conductivity, strong hydrophobicity, excellent tensile and compression performance, and has broad application prospects in the fields of heat insulation, heat preservation and cold preservation.

Description

Technical Field

[0001] This invention relates to the field of thermal insulation material preparation technology, and in particular to flexible thermal insulation organic aerogels and their preparation methods. Background Technology

[0002] Thermal insulation materials possess functions such as heat insulation, heat preservation, and cold insulation. They are widely used in clothing insulation, battery insulation, and other fields, effectively reducing energy consumption and potentially improving safety. Porous thermal insulation materials (such as aerogels) are an important class of thermal insulation materials. Inorganic aerogels (such as silica aerogels) have the advantage of good thermal insulation performance (low thermal conductivity), but they also have disadvantages such as high brittleness and strong hydrophilicity, making them prone to breakage. Furthermore, their thermal insulation performance decreases significantly with increasing humidity, making them unsuitable for practical applications.

[0003] Recent studies have shown that some hydrophobic crystalline polymers can gel under suitable conditions, forming organic aerogels upon drying. These aerogels often possess low density and a microporous structure. The presence of this microporous structure significantly reduces thermal conductivity, improving the aerogel's insulation properties. The hydrophobicity of the aerogel effectively prevents the influence of humidity on its insulation performance. Furthermore, appropriate methods (such as emulsion template methods) can effectively reduce polymer brittleness and promote the formation of unique microstructures (such as nanofiber structures) (Nanofibrous, emulsion-templated syndiotactic polymers with superhydrophobicity for oil spill cleanup, ACS Applied Materials & Interfaces 2019, 11, 36063-36072). This microstructure can further reduce thermal conductivity, improve insulation performance, and enhance the hydrophobicity of the aerogel. However, aerogels obtained by this method often have interconnected open-pore structures. The presence of interconnected pores facilitates the exchange of matter and energy, but reduces the final thermal insulation performance of the aerogel. Furthermore, such aerogels have extremely low density and are difficult to have flexible and tensile properties, which limits their practical applications. Summary of the Invention

[0004] To address the aforementioned technical problems, the present invention aims to provide a flexible, heat-insulating organic aerogel and its preparation method. In this invention, an oil-in-oil emulsion is coated onto a fabric, and an aerogel is formed on the surface and between the fabric fibers through the gelation of the polymer in the continuous phase of the emulsion. This material possesses advantages such as good flexibility, excellent mechanical properties, low thermal conductivity, and good hydrophobicity.

[0005] The first objective of this invention is to provide a method for preparing a flexible, heat-insulating organic aerogel, comprising the following steps:

[0006] (1) An oil-in-oil emulsion is obtained by mixing a non-polar oil phase with a polar oil phase; wherein the non-polar oil phase is a C12-C30 alkane or a mixture thereof; and the polar oil phase includes a crystalline polymer, an emulsion stabilizer and a polar solvent.

[0007] (2) The oil-in-oil emulsion described in step (1) is applied to the surface of the fabric and then cooled at a certain temperature to promote the gelation of the crystalline polymer. After drying, the flexible heat-insulating organic aerogel is obtained.

[0008] The second objective of this invention is to provide a thermally insulating organic aerogel with excellent mechanical properties, wherein the aerogel has a density of 20–300 mg / cm³. 3 The thermal conductivity of the material is 20–40 mW / (m K), the aerogel has a nanofiber structure with a fiber diameter of 20–200 nm, and the water contact angle is 95–140°.

[0009] Furthermore, the aerogel prepared by this invention has good mechanical properties, and it does not break when the compressive strain is 50%; the tensile strength can reach 1 to 50 MPa, and the elongation at break is 5% to 100%.

[0010] A third objective of this invention is to provide the use of the aforementioned flexible thermal insulation organic aerogel in the fields of thermal insulation, heat preservation, and cold preservation.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0012] This invention uses a polar solution of a crystallizable polymer as the continuous phase of an emulsion and a non-polar oil as the dispersed phase to form an oil-in-oil emulsion. This emulsion is then applied to the surface of a fabric. Through gelation of the crystallizable polymer and subsequent drying, an aerogel with a nanofiber structure is formed on and between the fabric fibers, improving thermal insulation performance. The presence of the fabric enhances the mechanical properties of the aerogel, imparting good flexibility and tensile strength. The closed-cell structure imparted by the emulsion template method, combined with the porous structure inherent in the aerogel itself, effectively reduces material density and improves thermal insulation performance. Simultaneously, the formed nanofiber structure enhances the hydrophobicity of the aerogel, ultimately resulting in a comprehensive combination of excellent mechanical properties, good thermal insulation, and hydrophobicity. Attached Figure Description

[0013] Figure 1 This is an optical photograph of the flexible thermal insulation organic aerogel in Embodiment 3 of the present invention;

[0014] Figure 2 This is a scanning electron microscope image of the surface of the flexible thermal insulation organic aerogel in Embodiment 2 of the present invention;

[0015] Figure 3These are thermogravimetric diagrams of the flexible thermal insulation organic aerogels in Examples 1 and 2 of this invention;

[0016] Figure 4 These are the compressive stress-strain curves of the flexible thermal insulation organic aerogels in Examples 1 and 3 of this invention;

[0017] Figure 5 These are the tensile stress-strain curves of the flexible thermal insulation organic aerogels in Examples 2 and 4 of this invention;

[0018] Figure 6 This refers to the water contact angle of the flexible thermal insulation organic aerogel in embodiments 1, 2, 3, 4, 5, 6 and 7 of the present invention;

[0019] Figure 7 It is the thermal conductivity of the flexible insulating organic aerogel in Examples 1, 2, 3, 4, 5, 6 and 7 of this invention. Detailed Implementation

[0020] The following details the implementation methods of the disclosed flexible thermal insulation organic aerogel and its preparation method.

[0021] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0022] Through extensive research, the applicant discovered that by selecting suitable crystalline polymers and combining them with the emulsion template method, and by controlling the emulsion composition and gelation conditions, the pore structure can be effectively controlled to obtain closed-cell aerogels without interconnected pores. Furthermore, by controlling the bonding between the emulsion and fabric, it is expected to obtain thermally insulating organic aerogels with excellent mechanical properties. This aerogel utilizes the low crystallinity of atypical crystalline polymers to effectively entangle fabric fibers, preventing phase separation and promising excellent mechanical properties. Simultaneously, due to the emulsion template method, closed-cell structures can be formed between fibers, further reducing material density and thermal conductivity. Finally, the hydrophobic properties of the polymer itself and the enhanced hydrophobicity of the microstructure (such as nanofibers) can improve the hydrophobicity of the organic aerogel, resulting in a flexible, mechanically sound, and thermally insulating organic thermally insulating aerogel. This aerogel has significant applications in clothing insulation, battery insulation, and building insulation. Based on this, this application was completed.

[0023] Preparation method of flexible heat-insulating organic aerogel

[0024] The first aspect of this invention provides a method for preparing a flexible heat-insulating organic aerogel, comprising the following steps:

[0025] (1) An oil-in-oil emulsion is obtained by mixing a non-polar oil phase with a polar oil phase; wherein the non-polar oil phase is a C12-C30 alkane or a mixture thereof; and the polar oil phase includes a crystalline polymer, an emulsion stabilizer and a polar solvent.

[0026] (2) The oil-in-oil emulsion described in step (1) is applied to the surface of the fabric and then cooled at a certain temperature to promote the gelation of the crystalline polymer. After drying, the flexible heat-insulating organic aerogel is obtained.

[0027] In the preparation method of flexible heat-insulating organic aerogel provided by the present invention, step (1) involves mixing a non-polar oil phase with a polar oil phase to obtain an oil-in-oil emulsion.

[0028] In step (1) of this application, the total volume fraction of the non-polar oil phase in the oil-in-oil emulsion is 10% to 85%. Optionally, the total volume fraction of the non-polar oil phase in the oil-in-oil emulsion may also be 10% to 25%, 25% to 50%, or 50% to 85%, etc.

[0029] In step (1) of this application, the non-polar oil phase is a C12-C30 alkane and a mixture thereof. Optionally, the non-polar oil phase is one or more of liquid paraffin and saturated C12-C30 alkane.

[0030] In step (1) of this application, the polar oil phase includes a crystalline polymer, an emulsion stabilizer, and a polar solvent.

[0031] In step (1) of this application, the weight-average molecular weight of the crystalline polymer is further defined as 10,000 to 500,000. Optionally, the weight-average molecular weight of the crystalline polymer can be 10,000 to 50,000, 50,000 to 100,000, 100,000 to 200,000, 200,000 to 300,000, 300,000 to 400,000, or 400,000 to 500,000, etc.

[0032] In step (1) of this application, the mass concentration of the crystalline polymer in the polar oil phase is further 10% to 40%. Optionally, the mass concentration of the crystalline polymer in the polar oil phase may also be 10% to 20%, 20% to 30%, or 30% to 40%, etc.

[0033] In step (1) of this application, the crystalline polymer is selected from one or more combinations of syndiotactic polymethyl methacrylate, isotactic polymethyl methacrylate, or polyethersulfone.

[0034] In step (1) of this application, the mass concentration of the emulsion stabilizer in the polar oil phase is further 1% to 10%. Optionally, the mass concentration of the emulsion stabilizer in the polar oil phase may also be 1% to 5% or 5% to 10%, etc.

[0035] In step (1) of this application, the emulsion stabilizer is further described as an amphiphilic block polymer. Optionally, the emulsion stabilizer is poloxamer.

[0036] In step (1) of this application, the polar solvent is further selected from one or more combinations of N,N-dimethylformamide, N,N-dimethylacetamide, and dimethylene sulfoxide.

[0037] In the preparation method of the flexible heat-insulating organic aerogel provided by the present invention, step (2) involves immersing the oil-in-oil emulsion described in step (1) onto the surface of the fabric, then cooling it at a certain temperature to promote the gelation of the crystalline polymer, and finally drying it to obtain the flexible heat-insulating organic aerogel.

[0038] In step (2) of this application, the fabric is one or more of cotton fabric, aramid fabric or acrylic fabric.

[0039] In step (2) of this application, the weight of the fabric is 150-300 g / m². 2 Optionally, the weight of the fabric can be, for example, 150–200 g / m². 2 200~250g / m 2 Or 250~300g / m 2 wait.

[0040] In step (2) of this application, the cooling temperature is -5 to 30°C. Optionally, the cooling gelation temperature can be -5 to 0°C, 0 to 10°C, 10 to 20°C, or 20 to 30°C, etc. The cooling time is 3 to 10 hours. Optionally, the gelation time is 3 to 5 hours, 5 to 8 hours, or 8 to 10 hours, etc.

[0041] In step (2) of this application, the drying is supercritical carbon dioxide drying or freeze drying.

[0042] This invention uses a polar solution of a crystallizable polymer as the continuous phase of an emulsion and a non-polar oil as the dispersed phase to form an oil-in-oil emulsion. This emulsion is then applied to the surface of a fabric. Through the gelation of the crystallizable polymer and subsequent drying, an aerogel with a nanofiber structure is formed on and between the fabric fibers, improving thermal insulation performance. The presence of the fabric enhances the mechanical properties of the aerogel, imparting good flexibility and tensile strength. The closed-cell structure imparted by the emulsion template method and the porous structure inherent in the aerogel itself effectively reduce material density and improve thermal insulation performance. Simultaneously, the formed nanofiber structure enhances the hydrophobicity of the aerogel, ultimately resulting in a product with excellent mechanical properties, good thermal insulation, and hydrophobicity.

[0043] Flexible thermal insulation organic aerogel

[0044] Another aspect of the present invention provides a flexible heat-insulating organic aerogel, which is prepared by the preparation method described in the first aspect of the present invention.

[0045] Furthermore, the density of the flexible thermal insulation organic aerogel is 20–300 mg / cm³. 3 Optionally, the density of the flexible thermal insulation organic aerogel can also be 20–100 mg / cm³. 3 100-200 mg / cm 3 Or 200-300 mg / cm 3 The thermal conductivity is 20–40 mW / (m K), and optionally, the thermal conductivity can be, for example, 20–30 mW / (m K) or 30–40 mW / (m K).

[0046] Furthermore, the flexible thermally insulating organic aerogel has a nanofiber structure with a diameter of 20–200 nm, optionally 20–50 nm, 50–100 nm, 100–150 nm, or 150–200 nm. The contact angle is 95°–140°. Optionally, the contact angle can be, for example, 95°–110°, 110°–125°, or 125°–140°.

[0047] Furthermore, the aerogel prepared by this invention exhibits excellent mechanical properties, showing no fracture at a compressive strain of 50%; its tensile strength can reach 1–50 MPa, and its elongation at break is 5%–100%. Optionally, the tensile strength can reach 1–10 MPa, 10–30 MPa, or 30–50 MPa, etc. The elongation at break is, for example, 5%–25%, 25%–50%, 50%–75%, or 75%–100%, etc.

[0048] application

[0049] The third aspect of the present invention provides the use of the flexible thermal insulation organic aerogel provided in the second aspect of the present invention in the fields of clothing insulation, battery insulation and building insulation.

[0050] Specifically, flexible thermal insulation organic aerogels can be used in fields such as clothing insulation, battery insulation, and building insulation.

[0051] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the following describes the preferred embodiments of the present invention in conjunction with detailed drawings.

[0052] The specific embodiments of the present invention will be described in further detail below with reference to the examples. These examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0053] In the following examples, unless otherwise stated, all reactants are commercially available products.

[0054] Example 1

[0055] This embodiment provides a method for preparing flexible thermal insulation organic aerogel, the steps of which are as follows:

[0056] 30g of polyethersulfone and 5g of F127 were dissolved in 65g of N,N-dimethylformamide by heating to obtain a polar oil phase. 20g of liquid paraffin was added dropwise to the above polar oil phase under mechanical stirring, and after mixing evenly, an oil-in-oil emulsion was obtained.

[0057] The above emulsion was coated onto the surface of cotton fabric and cooled at 5 degrees Celsius for 8 hours to allow for full gelation. Then, N,N-dimethylformamide was replaced with water, and the mixture was freeze-dried to obtain a flexible thermal insulation aerogel.

[0058] The resulting aerogel has a thermal decomposition temperature above 350℃ and can be compressed to 70% of its original height without breaking.

[0059] Example 2

[0060] This embodiment provides a method for preparing a flexible organic thermal insulation aerogel with excellent mechanical properties. The steps are the same as in Example 1, except that the amount of liquid paraffin added is 150g. The aerogel has a closed-cell structure and a nanofiber structure. Figure 2 It has a decomposition temperature above 350℃, a water contact angle above 130°, a thermal conductivity below 32mW / (m K), and a tensile elongation at break of up to 17%.

[0061] Example 3

[0062] This embodiment provides a method for preparing a flexible organic thermal insulation aerogel with excellent mechanical properties. The steps are the same as in Example 1, except that the mass of polyethersulfone is 15g. The resulting aerogel can be folded without breaking, has good flexibility, a water contact angle greater than 120°, a thermal conductivity less than 30mW / (m K), and can be compressed to 70% of its original height without breaking.

[0063] Example 4

[0064] This embodiment provides a method for preparing a flexible organic thermal insulation aerogel with excellent mechanical properties. The steps are the same as in Example 1, except that acetone is used to replace N,N-dimethylformamide, followed by supercritical carbon dioxide drying to prepare the flexible thermal insulation aerogel. The resulting aerogel has a water contact angle higher than 120° and a thermal conductivity lower than 30 mW / (m K).

[0065] Example 5

[0066] This embodiment provides a method for preparing a flexible organic thermal insulation aerogel with excellent mechanical properties. The steps are the same as in Example 4, except that the crystalline polymer used is syndiotactic polymethyl methacrylate.

[0067] Example 6

[0068] This embodiment provides a method for preparing a flexible organic thermal insulation aerogel with excellent mechanical properties, the steps of which are as follows:

[0069] This embodiment provides a method for preparing a chemically cross-linked cellulose-based porous thermal insulation material, the steps of which are the same as those in Example 4, except that the crystalline polymer used is isotactic polymethyl methacrylate.

[0070] Example 7

[0071] This embodiment provides a method for preparing a flexible organic thermal insulation aerogel with excellent mechanical properties. The steps are the same as in Example 5, except that the non-polar oil phase used is hexadecane.

[0072] Comparative Example 1

[0073] To form an open-cell structure, as in Example 2, 30g of polyethersulfone and 5g of F127 were dissolved in 65g of N,N-dimethylformamide by heating, resulting in a polar oil phase. 150g of liquid paraffin was added dropwise to the above polar oil phase under mechanical stirring, and after thorough mixing, an oil-in-oil emulsion was obtained. The emulsion was coated onto the surface of a cotton fabric, rapidly frozen using liquid nitrogen, and the N,N-dimethylformamide was replaced with water. Following freeze-drying, an open-cell aerogel without a nanofiber structure was obtained. The thermal conductivity of this aerogel was 50-60 mW / (mK), significantly higher than the 31.8 mW / (mK) of Example 2.

[0074] Comparative Example 2

[0075] Without using an emulsion method, a solution of 30g polyethersulfone and 65g N,N-dimethylformamide was directly coated onto the surface of a cotton fabric. After cooling at 5 degrees Celsius for 8 hours, a gel was formed. The N,N-dimethylformamide was then replaced with water, followed by freeze-drying to obtain an aerogel. This aerogel breaks upon folding and lacks flexibility; moreover, its thermal conductivity ranges from 40 to 60 mW / (mK), which is much higher than that of flexible aerogels formed based on emulsions.

[0076] Comparative Example 3

[0077] Without using fabric, as in Example 2, 30g of polyethersulfone and 5g of F127 were dissolved in 65g of N,N-dimethylformamide by heating to obtain a polar oil phase. 150g of liquid paraffin was added dropwise to the above polar oil phase under mechanical stirring, and after thorough mixing, an oil-in-oil emulsion was obtained. The emulsion was cooled at 5 degrees Celsius for 8 hours to form a gel. The N,N-dimethylformamide was then replaced with water, and the gel was freeze-dried to obtain an aerogel. The tensile breaking rate of this aerogel was 1%, significantly lower than the 17% of Example 2.

[0078] Table 1 shows the aerogel performance test results. Among them:

[0079] Density: The density of aerogel is determined by its mass-volume ratio. At least five different parts of the same sample are measured, and the average of the five measurements is taken as the final result.

[0080] Thermal conductivity: The thermal conductivity of the aerogel was measured by HotDisk TPS2500S at room temperature, and the average of three measurements was taken as the final result.

[0081] Compression properties: The compression properties of the aerogel were evaluated using an Instron 5967 universal testing machine. The compression rate was 10% height / min, at room temperature, until 70% of the sample height (the instrument's limit). The compressive modulus and compressive stress at 70% strain were determined based on the stress-strain curve.

[0082] Tensile properties: The aerogel was cut into strips (10.0 cm in length, 2.0 cm in width, and 0.2 cm in thickness) and stretched (using an Instron-3365 dual-arm material testing machine) at a fixed stretching rate of 10 mm / min until the aerogel was broken. The tensile stress-strain curve was obtained to determine the elongation at break, tensile modulus, and fracture stress.

[0083] Porous and nanofiber structures: The porous and nanofiber structures of the aerogel were determined using scanning electron microscopy (Hitachi S8100). The aerogel was first fractured in liquid nitrogen, and the fracture surface was sputter-coated with gold before observation. By analyzing the scanning electron microscope images, the diameters of the pores and fibers were determined, respectively.

[0084] Contact angle: The contact angle of the aerogel was determined using a Drop Shape Analyzer (DSA100S). Approximately 6 μL of water was dropped onto the aerogel surface for measurement. Measurements were taken at least 5 different locations for the same sample, and the average value was calculated.

[0085] Table 1

[0086]

[0087] As shown in Table 1, the thermal decomposition temperature of aerogels can reach above 400℃, making them suitable for thermal insulation applications at higher temperatures (such as below 300℃). The density of aerogels depends on the emulsion composition and the fabric, etc. Lower density helps to impart a lower thermal conductivity to aerogels, giving them better thermal insulation and cold insulation functions. All aerogels have good compressibility, reaching the instrument's limit without breaking. Furthermore, the tensile fracture rate of aerogels can reach 10%-23%, which is often difficult to achieve for aerogels. The microstructure provided by nanofibers gives aerogels a high contact angle, improving their hydrophobicity.

[0088] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a flexible, heat-insulating organic aerogel, characterized in that, Includes the following steps: (1) An oil-in-oil emulsion is obtained by mixing a non-polar oil phase with a polar oil phase; wherein the non-polar oil phase is a C12-C30 alkane or a mixture thereof; the polar oil phase includes a crystalline polymer, an emulsion stabilizer and a polar solvent; the crystalline polymer is selected from one or more combinations of syndiotactic polymethyl methacrylate, isotactic polymethyl methacrylate or polyethersulfone. (2) immersing the oil-in-oil emulsion described in step (1) on the surface of the fabric, and then cooling at a certain temperature, the cooling temperature is -5~30 °C, the cooling time is 3~10 hours, to make the crystalline polymer gelation, and after drying, the flexible thermal insulation organic aerogel is obtained, the flexible thermal insulation organic aerogel is a closed-cell aerogel; the density of the flexible thermal insulation organic aerogel is 20 ~ 300 mg / cm 3 ; With a thermal conductivity of 20 ~ 40 mW / (m·K), no breakage when compressed up to 50%, and a tensile elongation at break of 5% ~ 100%, this flexible thermal insulating organic aerogel has a nanofiber structure with a diameter of 20 ~ 200 nm and a contact angle of 95° ~ 140°.

2. The method for preparing the flexible thermal insulation organic aerogel according to claim 1, characterized in that: In step (1), the total volume fraction of the nonpolar oil phase in the oil-in-oil emulsion is 10% to 85%. And / or, the nonpolar oil phase is selected from one or more combinations of liquid paraffin, C12-C30 saturated alkanes.

3. The method for preparing the flexible thermal insulation organic aerogel according to claim 1, characterized in that: In step (1), the weight-average molecular weight of the crystalline polymer is 10,000 to 500,000; And / or, in step (1), the mass concentration of the crystalline polymer in the polar oil phase is 10% to 40%.

4. The method for preparing the flexible thermal insulation organic aerogel according to claim 1, characterized in that: In step (1), the mass concentration of the emulsion stabilizer in the polar oil phase is 1% to 10%; And / or, in step (1), the emulsion stabilizer is an amphiphilic block polymer, and the amphiphilic block polymer is poloxamer.

5. The method for preparing the flexible thermal insulation organic aerogel according to claim 1, characterized in that: In step (1), the polar solvent is selected from... N,N -Dimethylformamide, N,N - One or more combinations of dimethylacetamide and dimethylene sulfoxide.

6. The method for preparing the flexible thermal insulation organic aerogel according to claim 1, characterized in that: In step (2), the fabric is one or more of cotton fabric, aramid fabric or acrylic fabric; And / or, in step (2), the weight of the fabric is 150~300 g / m². 2 .

7. The method for preparing the flexible thermal insulation organic aerogel according to claim 1, characterized in that: In step (2), the drying is supercritical carbon dioxide drying or freeze drying.

8. A flexible thermally insulating organic aerogel, prepared by the method described in any one of claims 1 to 7, characterized in that: The density of the flexible thermal insulation organic aerogel is 20~300 mg / cm³. 3 ; The thermal conductivity is 20 ~ 40 mW / (m·K).

9. The flexible thermal insulation organic aerogel according to claim 8, characterized in that: It exhibits no breakage even with a compression ratio as high as 50%, and its tensile elongation at break is 5%~100%. And / or, the flexible thermal insulation organic aerogel has a nanofiber structure with a diameter of 20~200 nm and a contact angle of 95°~140°.

10. The use of the flexible thermal insulation organic aerogel according to claim 8 or 9 in the fields of thermal insulation, heat preservation and cold preservation.

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