A polyimide-polysiloxane block copolymer shape memory aerogel and its preparation method
By preparing polyimide-polysiloxane block copolymer aerogels, the problems of low deformation temperature and high brittleness of shape memory aerogels have been solved, realizing an aerogel with both high-temperature stability and toughness, thus expanding its application in the aerospace field.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- JIANGNAN UNIV
- Filing Date
- 2024-07-10
- Publication Date
- 2026-06-30
AI Technical Summary
Existing shape memory aerogels suffer from problems such as low deformation temperature, poor temperature resistance, and high brittleness, making it difficult to meet the application requirements in the aerospace field.
By preparing polyimide-polysiloxane block copolymers, flexible polysiloxane molecular chains are introduced and combined with polyimide backbones to form aerogels with both high-temperature stability and toughness, which can then be used to achieve complex structure molding using 3D printing technology.
The deformation temperature and toughness of aerogels have been improved, enabling the molding of complex structures and meeting the application requirements of extreme environments such as aerospace.
Smart Images
Figure CN118702961B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of polymer materials technology, and in particular to a polyimide-polysiloxane block copolymer shape memory aerogel and its preparation method. Background Technology
[0002] Shape memory materials are a new type of smart material that can change shape in response to external stimuli (such as heat, light, electric current, pH, magnetic fields, and humidity). When the external stimulus is removed, the deformed state can be fixed, and when the external stimulus reappears, it can reversibly return to its initial state. This material is widely used in medical, aerospace, and automotive fields. As smart materials continue to develop, the required structures and functions are becoming increasingly complex. Traditional shape memory materials have relatively simple molding processes, making it difficult to manufacture complex structures. Utilizing 3D printing technology to customize smart materials has become a key solution to these problems.
[0003] Aerogels are a new type of material with micro-nano three-dimensional porous structures, possessing characteristics such as high porosity, low density, and high specific surface area. They have broad application prospects in aerospace, thermal insulation, sound insulation, flame retardant, flexible, vibration damping, and energy storage devices. Compared with shape memory alloys or shape memory polymers, shape memory aerogels combine the low density, high porosity, and low dielectric properties of aerogels with the deformability and recoverability of shape memory materials. Therefore, they can endow smart deformable materials with many properties such as lightweight, thermal insulation, vibration damping and noise reduction, and low dielectric, which is expected to further improve the overall performance of smart materials. However, most of the shape memory aerogels reported so far suffer from problems such as low deformation temperature, poor temperature resistance, and high brittleness, which cannot meet the requirements of high temperature resistance under extreme conditions, thus limiting the application of shape memory aerogels in the aerospace field.
[0004] Polyimide is a general term for a class of polymers containing imide rings (-CO-N-CO-) in their main chain. It possesses high thermal stability, good mechanical properties, excellent weather resistance, high insulation, and superior radiation resistance, meeting the application requirements of harsh environments (such as high temperatures and space irradiation), thus making it highly favored in the aerospace field. Furthermore, the polyimide molecular chain structure offers flexible designability; by controlling the molecular structure, a series of shape memory polyimide materials with tunable glass transition temperatures (typically above 200℃) can be obtained, thereby meeting the needs of space applications. However, traditional polyimide molecular chains contain phenyl and biphenyl structures, resulting in high rigidity and weak deformation ability, making it difficult to exhibit shape memory effects. Simultaneously, the materials are relatively brittle, limiting their applications. Summary of the Invention
[0005] To address the aforementioned problems in existing technologies, this invention provides a polyimide-polysiloxane block copolymer shape memory aerogel and its preparation method. This invention improves the deformation temperature of the shape memory aerogel, mitigating its poor shape memory performance and toughness, while enabling the molding of complex structures to meet application requirements in fields such as deployable spatial structures.
[0006] The technical solution of the present invention is as follows:
[0007] The first objective of this invention is to provide a method for preparing polyimide-polysiloxane block copolymer shape memory aerogel, the method comprising the following steps:
[0008] (1) A polyamic acid solution was prepared by polycondensation of diamine monomer and dianhydride monomer in N,N-dimethylacetamide.
[0009] (2) The polyamic acid solution obtained in step (1) undergoes a condensation reaction with amino-terminated polysiloxane to obtain a polyamic acid-polysiloxane block copolymer solution.
[0010] (3) The polyamic acid-polysiloxane block copolymer solution obtained in step (2) is placed in water for solvent exchange. After the exchange, it is freeze-dried to obtain polyamic acid-polysiloxane block copolymer dry filaments.
[0011] (4) Mix the dried polyamic acid-polysiloxane block copolymer filaments obtained in step (3), triethylamine and water to obtain an aqueous solution of polyamic acid-polysiloxane block copolymer;
[0012] (5) After the aqueous solution of polyamic acid-polysiloxane block copolymer obtained in step (4) is molded, it is freeze-dried to obtain polyamic acid-polysiloxane block copolymer aerogel.
[0013] (6) The polyamic acid-polysiloxane block copolymer aerogel obtained in step (5) is subjected to imidization treatment to obtain polyimide-polysiloxane block copolymer aerogel, namely the polyimide-polysiloxane block copolymer shape memory aerogel.
[0014] In one embodiment of the present invention, in step (1), the diamine monomer is selected from any one or more of the following: 4,4'-diaminodiphenyl ether (ODA), 2,2-bis[4(4-aminophenoxy)phenyl]propane, p-phenylenediamine; the dianhydride monomer is selected from any one or more of the following: biphenyl dianhydride (BPDA), bisphenol A type diether dianhydride, pyromellitic dianhydride.
[0015] In one embodiment of the present invention, in step (1), the molar ratio of the diamine monomer to the dianhydride monomer is 1:(1.015-1.025).
[0016] In one embodiment of the present invention, in step (1), the polycondensation reaction is carried out in an ice bath for 4-6 hours, and the amount of N,N-dimethylacetamide (DMAc) added relative to the diamine is 24 L / mol of diamine.
[0017] In one embodiment of the present invention, in step (2), the amino-terminated polysiloxane is selected from any one or more of the following: poly(dimethylsiloxane), bis(3-aminopropyl)-terminated (APPs), and amino-terminated polydimethylsiloxane (PDMS).
[0018] In one embodiment of the present invention, in step (1), the preferred diamine monomer is 4,4'-diaminodiphenyl ether, and the dianhydride monomer is biphenyltetracarboxylic dianhydride.
[0019] In one embodiment of the present invention, in step (2), the preferred amino-terminated polysiloxane is poly(dimethylsiloxane), bis(3-aminopropyl)-terminated (APPs).
[0020] In one embodiment of the present invention, in step (2), the number average molecular weight of poly(dimethylsiloxane) and bis(3-aminopropyl)-terminated (APPs) is 1000, 3000, and 5000.
[0021] In one embodiment of the present invention, in step (2), the molar ratio of the amino-terminated polysiloxane to the diamine monomer in step (1) is (0.015-0.025):1.
[0022] In one embodiment of the present invention, in step (2), the polycondensation reaction time is 5-7 hours, and the polycondensation reaction is carried out in an ice bath.
[0023] In one embodiment of the present invention, in step (3), the solvent exchange time is 15-20 min; the solvent is ultrapure water and the solvent temperature is 0-5℃.
[0024] In one embodiment of the present invention, in step (3), the freeze-drying conditions are: freeze-drying at -90 to -60°C for 48 to 72 hours.
[0025] In one embodiment of the present invention, in step (4), the mass ratio of the polyamic acid-polysiloxane block copolymer dry filaments to triethylamine is 1:(0.3-0.5).
[0026] In one embodiment of the present invention, in step (4), the mixing is carried out at a stirring speed of 500-1000 rpm and a stirring time of 6-10 hours.
[0027] In one embodiment of the present invention, in step (4), the mass fraction of the polyamic acid-polysiloxane block copolymer in the aqueous solution of the polyamic acid-polysiloxane block copolymer is 5-8%.
[0028] In one embodiment of the present invention, in step (5), the aqueous solution is formed by cryogenic molding or 3D printing.
[0029] In one embodiment of the present invention, in step (5), the method of freeze molding is as follows: inject an aqueous solution of polyamic acid-polysiloxane block copolymer into a mold, and place the mold in a freezer for freeze molding; the freeze molding conditions are: -80℃ to 50℃, and the freeze molding time is 3-8 hours.
[0030] In one embodiment of the present invention, in step (5), the 3D printing method is as follows: a complex structure is formed by using a polyamic acid-polysiloxane block copolymer aqueous solution through low-temperature assisted ink direct writing 3D printing technology; the printing parameters are: the printing needle diameter is 0.35-0.6mm, the printing speed is 2.5-4mm / s, the printing air pressure is 0.2-0.4Mpa, and the cold plate temperature is -5-2℃.
[0031] In one embodiment of the present invention, in step (5), the freeze-drying conditions are: freeze-drying at -90℃ to 60℃ for 48-96 hours.
[0032] In one embodiment of the present invention, in step (6), the imidization conditions are as follows: under an inert atmosphere, the temperature is maintained at 100-200℃ for 40-60 min, at 200-250℃ for 20-40 min, at 280-300℃ for 30-40 min, and the heating rate is 1.5-2℃ / min.
[0033] A second objective of this invention is to provide a polyimide-polysiloxane block copolymer shape memory aerogel.
[0034] A third objective of this invention is to provide an application of polyimide-polysiloxane block copolymer shape memory aerogel for the preparation of thermal insulation materials, sound insulation materials, flame retardant materials, flexible materials, shock absorption materials, or energy storage devices.
[0035] The beneficial technical effects of this invention are as follows:
[0036] This invention introduces polysiloxane into traditional polyamic acid, improving the brittleness of traditional water-soluble polyimide aerogels. By introducing flexible polysiloxane molecular chains into the polyimide backbone, the content of soft and hard segments can be effectively adjusted to achieve optimal shape memory effect. At the same time, the high entanglement of polysiloxane effectively ensures the stability of the three-dimensional network structure during aerogel molding, reducing the thermal shrinkage rate caused by the release of internal free space during thermal imidization. In addition, the silicon-oxygen bonds can effectively prevent mechanical loss of the material under external force, effectively improving the toughness of the aerogel. The improved mechanical properties are conducive to meeting the application requirements of aerogel in various scenarios.
[0037] This invention introduces flexible polysiloxane molecular chains with adjustable molecular weight into rigid polyimide chains, which not only effectively solves the problem of difficult shape memory control but also improves the toughness of polyimide aerogels. Without sacrificing the excellent thermal stability of polyimide, both shape fixation rate and shape recovery rate are improved. Furthermore, the highly entangled polysiloxane molecular chains, although their introduction may disrupt the π-π conjugation effect between polyimide molecular chains and weaken hard segments, compensate for the loss in shape recovery rate caused by this highly cross-linked structure. Simultaneously, the bridging effect of the polysiloxane molecular chains within the polyimide effectively ensures stress transfer during shape recovery, significantly improving shape memory performance. This provides a new approach for obtaining polyimide aerogels with excellent shape memory properties.
[0038] The polyimide-polysiloxane block copolymer aerogel prepared by this invention controls the shape memory properties of the aerogel from the molecular structure. The preparation process is simple, low-cost, has good formability, and the shape of the aerogel can be designed, making it suitable for various environments.
[0039] The shape memory aerogel obtained by this invention has the characteristics of low density, high porosity, high deformation temperature, large elongation at break, and excellent shape memory performance. By introducing flexible polysiloxane into the rigid polyimide molecular chain, the reversible and fixed phases of shape memory are effectively balanced. This ensures the stability of the three-dimensional skeleton structure of the shape memory polyimide aerogel and overcomes the problem of poor shape fixation rate. At the same time, it effectively improves the toughness of the aerogel. This invention effectively expands the application of shape memory materials in the field of space deployable materials. Attached Figure Description
[0040] Figure 1 This is a microstructure diagram of the polyimide-polysiloxane block copolymer shape memory aerogel prepared in Example 1 of the present invention.
[0041] Figure 2 This is a physical illustration of the shape recovery process during the shape memory performance test of the polyimide-polysiloxane block copolymer shape memory aerogel prepared in Example 1 of the present invention.
[0042] Figure 3 This is a physical image of the shape memory aerogel with a complex structure, prepared as a 3D printed polyimide-polysiloxane block copolymer shape memory aerogel in Example 2 of the present invention.
[0043] Figure 4 The graph shows the results of quantitative testing of the shape memory performance of the polyimide-polysiloxane block copolymer shape memory aerogel prepared in Example 1 of the present invention using a dynamic thermomechanical analyzer. Detailed Implementation
[0044] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.
[0045] Linear shrinkage rate determination process: The diameter change of the aerogel before and after thermal imidization was measured respectively. The calculation formula is: shrinkage rate (%) = (d0-d) / d0; where d and d0 represent the diameter of the aerogel after freeze-drying and after imidization, respectively.
[0046] The shape retention rate determination process: Dynamic thermomechanical analysis was used to test the shape memory behavior of aerogels under stretching mode, and the shape retention rate of the aerogel shape memory process was obtained by analyzing the test data. The calculation formula is: R f =(ε unload -ε0) / (ε load -ε0), where ε load ε represents the maximum strain of the sample under tension, ε0 is the initial strain, and ε unload This represents the constant strain after cooling and unloading.
[0047] Recovery rate determination process: Dynamic thermomechanical analysis technology was used to test the shape memory behavior of aerogel under tensile mode, and the shape recovery rate of the aerogel shape memory process was obtained by analyzing the test data. The calculation formula is: R f =(ε unload -ε rec ) / (ε load -ε0), where ε load ε represents the maximum strain of the sample under tension. rec ε0 is the recovery strain under tension, ε0 is the initial strain, and ε0 is the recovery strain. unload This represents the constant strain after cooling and unloading.
[0048] Example 1
[0049] A method for preparing a polyimide-polysiloxane block copolymer shape memory aerogel includes the following steps:
[0050] (1) Weigh 10 mmol ODA and 10.2 mmol BPDA. First, add 10 mmol ODA to 45 ml DMAc and stir to dissolve it under ice-water bath. After dissolving, add 10 mmol BPDA in three equal portions. After reacting for 3 hours, add the remaining 0.2 mmol BPDA and react for 2 hours. Then add 0.2 mmol of poly(dimethylsiloxane) with a molecular weight of 3000 and bis(3-aminopropyl) end-capped. React for 5 hours to obtain a viscous polyamic acid-polysiloxane block copolymer solution. Place it in a refrigerator for aging for 10 hours and set aside for use.
[0051] (2) Take a large amount of ultrapure water and place it in an ice bath. Slowly flow the polyamic acid-polysiloxane block copolymer solution obtained in step (1) into the ultrapure water and stir to obtain a filamentous gel. Stir thoroughly and freeze the obtained filamentous gel at 60°C for 6 hours to obtain frozen filaments. Place them in a freeze dryer and freeze dry at -70°C for 72 hours to obtain polyamic acid-polysiloxane block copolymer dry filaments.
[0052] (3) Take 0.6g of the polyamic acid-polysiloxane block copolymer filaments obtained in step (2) and dissolve them in 9.4ml of water, and add 0.198g of triethylamine to accelerate the dissolution, so as to obtain an aqueous solution of polyamic acid-polysiloxane block copolymer;
[0053] (4) Pour the aqueous solution of polyamic acid-polysiloxane block copolymer obtained in step (3) into a mold, put the mold into a freezer, freeze at 70°C for 3 hours, and then put the mold into a freeze dryer for freeze drying to obtain polyamic acid-polysiloxane block copolymer aerogel.
[0054] (5) The polyamic acid-polysiloxane block copolymer aerogel obtained in step (4) above is placed in a tube furnace and thermal imidized at high temperature under a nitrogen atmosphere. The thermal imidization program is set as follows: heating from 30°C to 150°C for 60 minutes, holding at 150°C for 30 minutes, heating from 150°C to 200°C for 25 minutes, holding at 200°C for 30 minutes, heating from 200°C to 250°C for 25 minutes, holding at 250°C for 30 minutes, heating from 250°C to 300°C for 25 minutes, holding at 300°C for 30 minutes, and then cooling down to finally obtain the polyimide-polysiloxane block copolymer aerogel.
[0055] Figure 1 The image shows the microstructure of the polyimide-polysiloxane block copolymer shape memory aerogel prepared in this embodiment. As can be roughly seen from the image, the pore size of the aerogel is approximately 40-60 μm.
[0056] Figure 2This is a physical illustration of the shape recovery process during the shape memory performance test of the polyimide-polysiloxane block copolymer shape memory aerogel prepared in this embodiment. The aerogel exhibits excellent shape and fixation recovery effects.
[0057] Figure 4 The shape memory performance of the polyimide-polysiloxane block copolymer shape memory aerogel prepared in this embodiment was quantitatively tested using a dynamic thermomechanical analyzer. The calculated shape fixation rate was 96.3% and the shape recovery rate was 98.4%.
[0058] The properties of the obtained polyimide-polysiloxane block copolymer shape memory aerogel were determined, and the results are shown in Table 1-2.
[0059] Table 1
[0060] Shape memory aerogel transition temperature (°C) Decomposition temperature (°C) Linear shrinkage rate (%) 295 560 26.73
[0061] Table 2
[0062]
[0063] Example 2
[0064] A method for preparing a polyimide-polysiloxane block copolymer shape memory aerogel includes the following steps:
[0065] Steps (1)–(3) and (5) are the same as in Example 1; the difference lies in step (4).
[0066] (4) Pour the aqueous solution of polyamic acid-polysiloxane block copolymer obtained in step (3) into a 3D printing syringe, obtain the printing model in 3D MAX software in advance, print on a cold plate at 2°C, put the printed sample into a freezer and freeze at 70°C for 3 hours, and then put the printed sample into a freeze dryer and freeze dry at -70°C for 72 hours to obtain polyamic acid-polysiloxane block copolymer aerogel.
[0067] Figure 3 This is a physical image of the shape memory aerogel with a complex structure prepared in this embodiment, which is a 3D printed polyimide-polysiloxane block copolymer. The cube structure obtained by printing can be restored under thermal drive after being programmed into a box. It can also maintain good shape memory performance after multiple cycles.
[0068] Example 3
[0069] A method for preparing a polyimide-polysiloxane block copolymer shape memory aerogel includes the following steps:
[0070] Same as Example 1, except that: in step (1), the added poly(dimethylsiloxane) has a molecular weight of 1000 (3-aminopropyl); in step (3), 0.234g of triethylamine is added.
[0071] The properties of the obtained polyimide-polysiloxane block copolymer shape memory aerogel were determined. The results showed that the shape memory aerogel transition temperature was 310℃, the decomposition temperature was 565℃, the shrinkage rate was 25.83%, the shape fixation rate was 97.1% and the shape recovery rate was 91.8% in the first cycle, the shape fixation rate was 96.9% and the shape recovery rate was 93.5% in the second cycle, and the shape fixation rate was 96.5% and the shape recovery rate was 94.3% in the third cycle.
[0072] Example 4
[0073] A method for preparing a polyimide-polysiloxane block copolymer shape memory aerogel includes the following steps:
[0074] Same as Example 1, except that: in step (1), the added poly(dimethylsiloxane) has a molecular weight of 5000 (3-aminopropyl); in step (3), 0.168g of triethylamine is added.
[0075] The properties of the obtained polyimide-polysiloxane block copolymer shape memory aerogel were determined. The results showed that the shape memory aerogel had a transition temperature of 290℃, a decomposition temperature of 550℃, and a shrinkage rate of 28.35%. The shape fixation rate was 91.8% and the shape recovery rate was 90.4% in the first cycle; 90.2% and 96.3% in the second cycle; and 90.0% and 97.7% in the third cycle.
[0076] Comparative Example 1
[0077] A method for preparing polyimide aerogel includes the following steps:
[0078] (1) Weigh 10 mmol ODA and 10.2 mmol BPDA. First, add 10 mmol ODA to 45 ml DMAc and stir to dissolve it under ice water bath. After dissolving, add 10 mmol BPDA in three equal portions. After reacting for 3 hours, add the remaining 0.2 mmol BPDA and react for another 3 hours to obtain a viscous polyamic acid precursor solution. Place it in a refrigerator for aging for 10 hours before use.
[0079] (2) Take a large amount of ultrapure water and place it in an ice bath. Slowly pour the viscous precursor solution obtained in step (1) into the ultrapure water and stir it to obtain a filamentous gel. Stir it thoroughly and freeze the filamentous gel at 60°C for 6 hours to obtain frozen filaments. Put it into a freeze dryer and freeze dry it at -70°C for 72 hours to obtain polyamic acid dried filaments.
[0080] (3) Dissolve 0.6g of the polyamic acid filaments obtained in step (2) in 9.4ml of water, and add 0.258g of triethylamine to accelerate dissolution, to obtain a polyamic acid aqueous solution;
[0081] (4) Pour the polyamic acid aqueous solution obtained in step (3) into the mold, put the mold into the freezer, freeze at 70°C for 3 hours, and then put the mold into the freeze dryer and freeze dry at -70°C for 72 hours to obtain polyamic acid aerogel.
[0082] (5) The polyamic acid aerogel obtained in step (4) is placed in a tube furnace and thermally imidized at high temperature under a nitrogen atmosphere. The thermal imidization program is set as follows: heating from 30°C to 150°C for 60 minutes, holding at 150°C for 30 minutes, heating from 150°C to 200°C for 25 minutes, holding at 200°C for 30 minutes, heating from 200°C to 250°C for 25 minutes, holding at 250°C for 30 minutes, heating from 250°C to 300°C for 25 minutes, holding at 300°C for 30 minutes, and then cooling down to finally obtain polyimide aerogel.
[0083] The properties of the obtained polyimide aerogel were measured, and the results showed that the shape memory aerogel had a transition temperature of 330℃, a thermal decomposition temperature of 565℃, and a shrinkage rate of 31.40%. Dynamic mechanical analysis did not reveal any obvious shape memory behavior.
Claims
1. A method for preparing a polyimide-polysiloxane block copolymer shape memory aerogel, characterized by, The preparation method includes the following steps: (1) A polyamic acid solution is prepared by polycondensation reaction of diamine monomer and dianhydride monomer; (2) The polyamic acid solution obtained in step (1) undergoes a condensation reaction with amino-terminated polysiloxane to obtain a polyamic acid-polysiloxane block copolymer solution. (3) The polyamic acid-polysiloxane block copolymer solution obtained in step (2) was placed in water for solvent exchange. After the exchange, it was freeze-dried to obtain polyamic acid-polysiloxane block copolymer dry filaments. (4) Mix the dried polyamic acid-polysiloxane block copolymer filaments obtained in step (3), triethylamine and water to obtain an aqueous solution of polyamic acid-polysiloxane block copolymer; (5) After the aqueous solution of polyamic acid-polysiloxane block copolymer obtained in step (4) is molded, it is freeze-dried to obtain polyamic acid-polysiloxane block copolymer aerogel. (6) The polyamic acid-polysiloxane block copolymer aerogel obtained in step (5) is subjected to imidization treatment to obtain polyimide-polysiloxane block copolymer aerogel, namely the polyimide-polysiloxane block copolymer shape memory aerogel.
2. The preparation method according to claim 1, characterized in that, In step (1), the diamine monomer is selected from any one or more of the following: 4,4'-diaminodiphenyl ether, 2,2-bis[4(4-aminophenoxy)phenyl]propane, p-phenylenediamine; the dianhydride monomer is selected from any one or more of the following: biphenyltetracarboxylic dianhydride, bisphenol A type diether dianhydride, pyromellitic dianhydride.
3. The preparation method according to claim 1, characterized in that, In step (1), the molar ratio of the diamine monomer to the dianhydride monomer is 1:(1.015-1.025).
4. The preparation method according to claim 1, characterized in that, In step (2), the amino-terminated polysiloxane is selected from any one or more of the following: poly(dimethylsiloxane), bis(3-aminopropyl)-terminated, amino-terminated polydimethylsiloxane.
5. The preparation method according to claim 1, characterized in that, In step (2), the molar ratio of the amino-terminated polysiloxane to the diamine monomer in step (1) is (0.015-0.025):
1.
6. The preparation method according to claim 1, characterized in that, In step (4), the mass ratio of polyamic acid-polysiloxane block copolymer dry filaments to triethylamine is 1:(0.3-0.5).
7. The preparation method according to claim 1, characterized in that, In step (5), the aqueous solution is formed by freeze-drying or 3D printing; the freeze-drying conditions are: freeze-drying at -90℃ to 60℃ for 48-96 hours.
8. The preparation method according to claim 1, characterized in that, In step (6), the imidization conditions are as follows: under an inert atmosphere, hold at 100-200℃ for 40-60 min, at 200-250℃ for 20-40 min, at 280-300℃ for 30-40 min, with a heating rate of 1.5-2℃ / min.
9. A polyimide-polysiloxane block copolymer shape memory aerogel prepared by the preparation method according to any one of claims 1-8.
10. An application of the polyimide-polysiloxane block copolymer shape memory aerogel according to claim 9, characterized in that, Used to prepare heat insulation materials, sound insulation materials, flame retardant materials, flexible materials, shock absorption materials, or energy storage devices.