3D printing organic-inorganic hybrid aerogel and preparation method thereof

Abstract

The present application relates to a kind of 3D printing organic-inorganic hybrid aerogel and its preparation method, comprising the following steps: amine group bridged siloxane, organic solvent, thickening agent are mixed and stirred, after defoaming, sol ink is obtained;Water, organic solvent, surfactant are mixed and stirred to obtain water bath liquid, and heated to a certain temperature;Sol ink is printed to water bath liquid, and it is solidified and formed to obtain printed part after waiting;Printed part is placed in oven and aged, and cleaned with organic solvent to remove residual impurities;Printed part is dried, and the aerogel is prepared.The present application is based on the self-catalytic gel characteristics of organic-inorganic hybrid aerogel, and the reaction gel is formed by amine group bridged siloxane in water as solidification mode, and 3D printing aerogel with controllable nanopore structure and customized geometry is prepared, and the buoyancy provided by water bath liquid is beneficial to 3D printing of large-scale, high-thickness or suspended structure, which can effectively expand the application prospect of 3D printing aerogel in many fields.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of 3D printing aerogel, in particular to a 3D printing organic-inorganic hybrid aerogel and a preparation method thereof. BACKGROUND

[0002] Aerogel is currently known as the solid material with the lowest thermal conductivity and the smallest density. Its unique three-dimensional nano-porous network structure makes it exhibit unique performance in mechanics, thermotics, electricity, optics, acoustics, etc. At present, China's aerogel industry is in the fourth wave of industrialization. Aerogel-based products represented by SiO2 aerogel have achieved relatively mature applications in the fields of aerospace, petroleum and chemical industry, and heat pipe, and are accelerating the application in the fields of building energy saving, new energy vehicles, and electronic device thermal management. However, the development of aerogel materials also faces some difficulties and needs to be broken through. Aerogel materials have excellent application performance due to their low density and high specific surface area, but at the same time, they also have the problem of intrinsic brittleness, which is easy to break and powder, and is difficult to realize on-demand shaping by traditional subtractive manufacturing post-processing technology, and cannot meet the needs of irregular appearance in actual application scenarios, and is prone to "leakage" of heat, sound, etc. problems, which seriously restricts the performance and wide application. Therefore, it is urgent to develop a new manufacturing technology that can be customized to have irregular shapes to solve this problem. The 3D printing aerogel technology that can be customized to synthesize aerogels with complex structures without complex post-processing is expected to become a key to breaking through the bottleneck of large-scale application of aerogel materials.

[0003] In the prior art, patent document (publication number CN117623322A) discloses printing transparent silica aerogel by using organosiloxane as precursor, surfactant as rheological modifier, and acid-base catalyst as catalyst; patent document (publication number CN116969474A) discloses a 3D printing silica composite aerogel preparation method cured in an ammonia atmosphere. However, these methods are based on sol-gel reaction of molecular-based ink for printing, and the rheological property of such ink is seriously dependent on chemical reaction, which is difficult to control. On the one hand, if the sol-gel reaction is too fast, the ink is easy to precipitate or gel quickly, and it is difficult to obtain ink that can remain stable for a long time during printing; on the other hand, if the sol-gel reaction is too slow, the viscosity of the molecular-based ink is low, and it is difficult to support the structure shape of 3D printing. At the same time, with the increase of printing height, the printed structure will shrink or even collapse in the height direction due to the influence of the weight of the printing filament, which seriously limits the printing of structures with high dimensions. In addition, the ink formula of these methods generally contains acid-base catalyst, which not only causes corrosion damage to the equipment, but also affects the structure and performance of the printed components.

[0004] Therefore, it is a technical problem to be solved by those skilled in the art to develop a 3D printing aerogel process with simple process, easy to control and large size printing capacity by combining 3D printing technology and molecular derived sol-gel.

[0005] The information disclosed in this section is intended only to enhance the understanding of the general background of the present application and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art that is already known to those skilled in the art. SUMMARY

[0006] The purpose of the present application is to provide a 3D printing organic-inorganic hybrid aerogel and a preparation method thereof to solve the problems of complex process, difficult to control gel process and limited printing height of the existing aerogel 3D printing technology.

[0007] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0008] In a first aspect, the present application provides a preparation method of a 3D printing organic-inorganic hybrid aerogel, comprising the following steps:

[0009] S1, mixing and stirring amine-based bridged siloxane, organic solvent and thickening agent to obtain sol ink after defoaming;

[0010] S2, mixing and stirring water, organic solvent and surfactant to obtain a water bath solution, and heating to a certain temperature;

[0011] S3, printing the sol ink in step S1 into the water bath solution in step S2, and waiting for it to solidify and form a printed part;

[0012] S4, placing the printed part in step S3 in an oven for aging, and cleaning with an organic solvent to remove residual impurities;

[0013] S5, drying the printed part in step S4 to obtain an organic-inorganic hybrid aerogel.

[0014] The preparation method of the 3D printing organic-inorganic hybrid aerogel provided by the present application uses amine-based bridged siloxane as a silicon source, utilizes the self-catalytic gelation mechanism that it will rapidly hydrolyze and condense when it comes into contact with water, places the molecular sol-gel reaction after the 3D printing extrusion process, and directly extrudes the ink into the binary water bath solution containing water. The ink quickly gels and forms a three-dimensional structure with good self-supporting ability in the solution. After a series of steps such as aging, replacement and drying, an organic-inorganic hybrid aerogel with a nano-porous network skeleton structure is obtained, which has potential application prospects in the field of thermal and acoustic insulation.

[0015] Preferably, in step S1, the mass ratio of the amine-based bridged siloxane, the organic solvent and the thickening agent is 100: (10-600): (8-75).

[0016] Preferably, in step S1, the amine-based bridged siloxane comprises one or more of bis[3-(trimethoxysilyl)propyl]amine, bis(3-triethoxysilylpropyl)amine, 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane; the thickening agent comprises one or more of fumed silica, silica aerogel powder, carbomer, hydroxyethyl cellulose, polyvinyl alcohol and cellulose nanofiber; in steps S1, S2 and S4, the organic solvent comprises one or more of ethanol, methanol, acetone, n-heptane and n-hexane.

[0017] In step S1 of the present application, the amine-based bridged siloxane serves as a silicon source for subsequent construction of a network skeleton, the organic solvent plays a dispersing role, and the thickening agent is used to adjust the rheological property of the ink, so that the ink has a shear thinning property. Thanks to the buoyancy of the water bath liquid and the rapid autocatalytic gelation rate, the viscosity requirement of the ink for 3D printing is greatly reduced, and the influence of the thickening agent on the structure and performance of the aerogel is effectively reduced. In addition, water cannot be added in step S1, otherwise the amine-based bridged siloxane will hydrolyze and condense, thereby losing its effectiveness.

[0018] Preferably, in step S2, the volume ratio of the water and the organic solvent is 1-4, and the addition amount of the surfactant is 0.1-10 g / L.

[0019] Preferably, in step S2, the surfactant comprises one or more of cetyltrimethylammonium bromide, sodium dodecyl sulfate, sodium dodecylbenzenesulfonate and benzalkonium chloride.

[0020] Preferably, in step S2, the water bath liquid is heated to 20-60℃, preferably in an oven.

[0021] In step S2 of the present application, water is used as a reactant for subsequent reaction with the amine-based bridged siloxane, and the surfactant is used to reduce the surface tension of the water bath liquid, thereby inhibiting the diffusion of the ink in the water bath liquid due to the difference in tension. In addition, the reaction rate can be adjusted by changing the amount of the organic solvent and the temperature of the water bath liquid, thereby greatly reducing the stringent requirements of the printing process on the rheological property and viscosity of the ink.

[0022] Preferably, in step S3, the printing speed of the printing is 1-15 mm / s, the X, Y and Z axis moving speeds are all 10-40 mm / s, the extrusion ratio is 0.5-3.0, and the nozzle diameter is 0.1-2 mm.

[0023] In step S3 of this invention, the ink is printed into a binary solution containing water, where the amine group in the amino-bridged siloxane molecule binds hydrogen ions (H+) from the water molecule. + ), releasing hydroxide ions (OH-) - These OH - This process promotes the de-alcoholization and hydrolysis of the silicon source, converting methoxy groups into highly reactive silanol groups. These silanol groups then undergo dehydration condensation and cross-linking, transforming the solution into a sol. As the hydrolysis and condensation reactions continue, the silicon source molecules cross-link to form a three-dimensional nano-network framework structure. Simultaneously, phase separation occurs between the liquid solvent and the solid framework, completing self-catalytic gelation without the need for acid or base catalysts. With the ink rapidly gelling in the solution, a three-dimensional printed structure with excellent self-supporting capabilities is formed.

[0024] Preferably, in step S4, the aging time is 24~48h and the aging temperature is 30~60℃.

[0025] In step S4 of this invention, the strength of the skeleton structure is enhanced by aging, giving the printed part better mechanical properties. Residual water in the printed part is removed by organic solvent replacement to prevent excessive shrinkage during the drying process.

[0026] Preferably, in step S5, the drying includes any one of: supercritical carbon dioxide fluid drying, supercritical ethanol fluid drying, or vacuum freeze drying.

[0027] Preferably, the supercritical carbon dioxide drying process includes: first replacing the organic solvent in the printed part with ethanol, then placing it in supercritical carbon dioxide and drying it at a pressure of 8~20MPa and a temperature of 35~60℃ for 10~72h.

[0028] Preferably, the supercritical fluid drying of ethanol includes: first replacing the organic solvent in the printed part with ethanol, and then drying it at a pressure of 7~12MPa and a temperature of 245~270℃ for 10~72h.

[0029] Preferably, the vacuum freeze-drying process includes: first replacing the organic solvent in the printed parts with deionized water, then pre-freezing at a temperature of -80 to -40°C, and then drying at a vacuum of 5 to 15 Pa and a temperature of -60 to -20°C for 24 to 96 hours.

[0030] In step S5, the carbon dioxide supercritical fluid drying and the ethanol supercritical fluid drying can effectively avoid the influence of capillary force on the nano skeleton structure in the drying process, and can better maintain the three-dimensional nano network skeleton structure of the aerogel, and the material shrinkage rate is smaller, but compared with the vacuum freeze drying process, the cost is higher, and there is a certain safety hazard. The vacuum freeze drying process can effectively solve the damage of capillary force to the pore structure by directly sublimating the frozen liquid water into gaseous state and converting the gas-liquid interface into gas-solid interface, however, the volume of water will expand during the freezing process, which will damage the skeleton structure of the aerogel and reduce the strength, and the pore diameter of the organic-inorganic hybrid aerogel prepared by the vacuum freeze drying is generally micron, which will affect the heat insulation performance of the aerogel to a certain extent and weaken the inhibition of gaseous heat transfer.

[0031] In a second aspect, the present application provides an organic-inorganic hybrid aerogel prepared by the method.

[0032] By adopting the technical scheme, the present application has the following beneficial effects:

[0033] 1. The method for preparing the 3D-printed organic-inorganic hybrid aerogel provided by the present application utilizes the self-catalytic gelation mechanism of amine-based bridged siloxane, and places the molecular solvent-gel reaction after the 3D printing extrusion process, so that the ink formula is simple and stable, which not only solves the problems of instability, easy precipitation and difficult storage of traditional ink, but also realizes instant curing of the ink after contacting with the water bath liquid within a few seconds by controlling the reaction rate, thereby reducing the stringent requirements of the printing process on the rheological property and viscosity of the ink and helping to improve the resolution of the printed structure.

[0034] 2. The method for preparing the 3D-printed organic-inorganic hybrid aerogel provided by the present application utilizes the self-catalytic gelation mechanism of amine-based bridged siloxane as the curing method, which has low system complexity, low cost and simple operation compared with common ultraviolet curing, temperature-induced curing and ion crosslinking curing.

[0035] 3. The method for preparing the 3D-printed organic-inorganic hybrid aerogel provided by the present application, the printing and curing processes are both carried out in the water bath liquid, which can provide buoyancy support for the printed structure, not only can inhibit the deformation of the suspended structure caused by gravity, thereby widening the range of key application properties such as density and specific surface area of the 3D-printed aerogel, but also is beneficial to the 3D printing of large-scale, high-thickness or suspended structure aerogel devices. BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the specific embodiments of the present application or the prior art, the drawings needed to be used in the specific embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0037] Figure 1 Optical diagram of the printing process of the organic-inorganic hybrid aerogel in Example 1 of the present application;

[0038] Figure 2 Optical diagram of the printed organic-inorganic hybrid aerogel in Example 1 of the present application;

[0039] Figure 3 Micro-morphology diagram of the printed organic-inorganic hybrid aerogel in Example 1 of the present application;

[0040] Figure 4 Nitrogen adsorption-desorption isotherm curve of the printed organic-inorganic hybrid aerogel in Example 1 of the present application;

[0041] Figure 5 Pore size distribution curve of the printed organic-inorganic hybrid aerogel in Example 1 of the present application. DETAILED DESCRIPTION

[0042] The various exemplary embodiments of the present application will now be described in detail, which should not be considered as limiting the present application, but should be understood as a more detailed description of some aspects, characteristics and embodiments of the present application. Based on the examples in the present application, all other examples obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0043] It should be understood that the terms described in the present application are only for describing the specific embodiments, and are not intended to limit the present application. In addition, for the numerical range in the present application, it should be understood that each intermediate value between the upper limit and the lower limit of the range is also specifically disclosed. Each smaller range between any stated value or intermediate value in the range, and any other stated value or intermediate value in the range is also included in the present application. The upper limit and the lower limit of these smaller ranges can be independently included or excluded from the range.

[0044] Unless otherwise indicated, all technical and scientific terms have the same meaning as those one of ordinary skill in the art of the disclosure would understand. Although preferred methods and materials are described, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present disclosure. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials in connection with which the documents are cited. In case of conflict between the content of the specification and that of any document incorporated by reference, the content of the specification prevails.

[0045] Many modifications and variations of the present disclosure described in the detailed description of the specification can be made without departing from the scope or spirit of the present disclosure, which will be apparent to those skilled in the art. Other implementations of the disclosure will be apparent to those skilled in the art from the specification. The specification and examples of the disclosure are illustrative only.

[0046] As used herein, "comprise", "comprising", "have", "having", "include", "including", "contain", "containing", and the like, are open-ended terms that are intended to mean including, but not limited to. Example 1

[0047] The present embodiment provides a method for preparing a 3D printed organic-inorganic hybrid aerogel, comprising the following steps:

[0048] S1, mix 96g of bis[3-(trimethoxysilyl)propyl]amine, 64.6g of ethanol, 3.76g of fumed silica, and 18g of silica aerogel powder, stir for 8h, then defoam with a vacuum defoaming machine, the rotation speed is 1000rpm, and the defoaming time is 5min, to obtain a sol ink that can be used for printing.

[0049] S2, mix 100ml of water, 100ml of ethanol, and 1g of cetyltrimethylammonium bromide, stir until uniform, and then place in an oven and heat to 40℃.

[0050] S3, load the sol ink in step S1 into a 3D printer, use a nozzle with a diameter of 0.8mm to print into the water bath in step S2, the printing speed is 5mm / s, the X, Y, Z axis moving speed is 30mm / s, the extrusion ratio is 0.6, the filling rate is 30%, the printed shape is a grid-shaped cube with a length of 50mm, a width of 50mm, and a height of 10mm, and after printing, let it stand for 30min to solidify the printed part.

[0051] S4, place the printed part in step S3 in a 40℃ oven for aging, the aging time is 48h, then replace the aged printed part with ethanol to remove the residual impurities, the replacement time is 6 times, and the replacement time is every 6 hours.

[0052] S5, placing the printed piece after the replacement in step S4 in a carbon dioxide supercritical fluid environment with a temperature of 45 DEG C and a pressure of 12 MPa, and after the supercritical carbon dioxide fluid sufficiently replaces the ethanol in the printed piece, obtaining a 3D printed organic-inorganic hybrid aerogel with a size of 42 mm in length, 43 mm in width, and 9 mm in height.

[0053] The results show that the 3D printed organic-inorganic hybrid aerogel prepared in this embodiment has a density of 0.24 g / cm 3 , a specific surface area of 514.87 m 2 / g, and a compression strength of 0.5 MPa under a 10% strain.

[0054] Figure 1 The optical diagram of the printing process of the organic-inorganic hybrid aerogel in this embodiment, from which it can be seen that by placing the nozzle in the water bath for printing, a regular honeycomb structure can be formed according to the predetermined printing program.

[0055] Figure 2 The optical diagram of the printed organic-inorganic hybrid aerogel in this embodiment, from which it can be seen that the sample is white and has a regular honeycomb structure, and the printing layers are uniformly arranged, with high printing precision.

[0056] Figure 3 The micro-morphology diagram of the printed organic-inorganic hybrid aerogel in this embodiment, from which it can be seen that the aerogel is composed of nanoparticles that are cross-linked with each other at the micro level, forming a rich and developed nanoporous structure, and the pore structure size is relatively uniform.

[0057] Figure 4 The nitrogen adsorption-desorption isotherm curve of the printed organic-inorganic hybrid aerogel in this embodiment, from which it can be seen that the curve is a type IV isotherm, showing the typical adsorption-desorption characteristics of mesoporous structures.

[0058] Figure 5 The pore size distribution curve of the printed organic-inorganic hybrid aerogel in this embodiment, from which it can be seen that the pore size distribution of the aerogel is relatively concentrated, with a most probable pore size of about 4 nm, which is lower than the average free path of air molecules, and is conducive to blocking the heat transfer of gas molecules. Example 2

[0059] This embodiment provides a method for preparing a 3D printed organic-inorganic hybrid aerogel, comprising the following steps:

[0060] S1, 60 g of bis[3-(trimethoxysilyl)propyl]amine, 81 g of ethanol, 3.3 g of fumed silica and 16.5 g of silica aerogel powder were mixed and stirred for 8 h, and then defoamed by a vacuum defoaming machine at a speed of 1000 rpm for 5 min to obtain a sol ink that can be used for printing.

[0061] S2, 100 ml of water, 100 ml of ethanol and 1 g of cetyltrimethylammonium bromide were mixed and stirred uniformly, and then placed in an oven and heated to 40℃.

[0062] S3, the sol ink in step S1 was loaded into a 3D printer, and a nozzle with a diameter of 0.8 mm was used to print into the water bath liquid in step S2 at a printing speed of 5 mm / s, the X, Y and Z axis moving speeds were all 30 mm / s, the extrusion ratio was 0.6, the filling rate was 30%, the printed shape was a grid-shaped cube with a length of 50 mm, a width of 50 mm and a height of 10 mm, and the printed part was left to solidify for 30 min after printing.

[0063] S4, the printed part in step S3 was placed in a 40℃ oven for aging for 48 h, and then the aged printed part was replaced with ethanol to remove the residual impurities, and the replacement was performed 6 times, once every 6 hours.

[0064] S5, the replaced printed part in step S4 was placed in a carbon dioxide supercritical fluid environment with a temperature of 45℃ and a pressure of 12 MPa, and after the ethanol in the printed part was fully replaced by the supercritical carbon dioxide fluid, a 3D printed organic-inorganic hybrid aerogel with a size of 42 mm in length, 41 mm in width and 9 mm in height was obtained.

[0065] The results show that the 3D printed organic-inorganic hybrid aerogel prepared in this embodiment has a density of 0.23 g / cm 3 , a specific surface area of 479.17 m 2 / g and a compression strength of 0.4 MPa under a strain of 10%. Example 3

[0066] The present embodiment provides a preparation method of a 3D printed organic-inorganic hybrid aerogel, comprising the following steps:

[0067] S1, 60 g of bis[3-(trimethoxysilyl)propyl]amine, 81 g of ethanol, 3.3 g of fumed silica and 16.5 g of silica aerogel powder were mixed and stirred for 8 h, and then defoamed by a vacuum defoaming machine at a speed of 1000 rpm for 5 min to obtain a sol ink that can be used for printing.

[0068] S2, 100 ml of water, 100 ml of ethanol, 1 g of cetyltrimethylammonium bromide were mixed and stirred uniformly, and then placed in an oven and heated to 40℃.

[0069] S3, the sol ink in step S1 was loaded into a 3D printer, a nozzle with a diameter of 0.8 mm was used to print into the water bath liquid in step S2, the printing speed was 5 mm / s, the X, Y, Z axis moving speed was 30 mm / s, the extrusion ratio was 0.6, the filling rate was 30%, the printed shape was a grid-shaped cube with a length of 50 mm, a width of 50 mm and a height of 10 mm, and the printed part was left to solidify for 30 min after printing.

[0070] S4, the printed part in step S3 was placed in a 40℃ oven for aging, the aging time was 48 h, then the aged printed part was replaced with ethanol to remove the residual impurities, the replacement time was 6 times, every 6 hours.

[0071] S5, the replaced printed part in step S4 was placed in a carbon dioxide supercritical fluid environment with a temperature of 45℃ and a pressure of 12 MPa, and after the supercritical carbon dioxide fluid was fully replaced with ethanol in the printed part, a 3D printed organic-inorganic hybrid aerogel with a size of 43 mm long, 44 mm wide and 9 mm high was obtained.

[0072] The results show that the 3D printed organic-inorganic hybrid aerogel prepared in this embodiment has a density of 0.25 g / cm 3 , a specific surface area of 589.45 m 2 / g, and a compression strength of 0.6 MPa under 10% strain. Comparative Example 1

[0073] This comparative example is basically the same as Example 1, except that in step S1, when configuring the sol ink, the addition amount of bis[3-(trimethoxysilyl)propyl]amine and ethanol is 20.1 g and 140.5 g respectively (the mass ratio of the two is about 1:7), and the specific process is as follows: 20.1 g of bis[3-(trimethoxysilyl)propyl]amine, 140.5 g of ethanol, 3.76 g of fumed silica and 18 g of silica aerogel powder were mixed and stirred for 8 h, then defoaming was carried out with a vacuum defoaming machine, the rotating speed was 1000 rpm, and the defoaming time was 5 min, and the ink available for printing was obtained.

[0074] Because the mass ratio of amine group bridged siloxane in the ink is too low, the printed part cannot be completely gelatinized and solidified, and a printed structure with certain strength cannot be formed. The 3D printed organic-inorganic hybrid aerogel prepared in this comparative example has a density of 0.21 g / cm 3 , a specific surface area of 419.48 m 2The compression strength under 10% strain is 0.12 Mpa. Comparative Example 2

[0075] This comparative example is basically the same as Example 1, except that in step S2, pure water is used as the water bath liquid, and no ethanol and cetyltrimethylammonium bromide are added. The specific process is as follows: 200 ml of water is placed in an oven and heated to 40°C.

[0076] Because the surface tension of pure water is large, the ink spreads to some extent when extruded into the water, resulting in deformation of the printed structure and a decrease in strength, and the printing cannot be completed normally. Comparative Example 3

[0077] This comparative example is basically the same as Example 1, except that in step S5, the drying of the aerogel is performed under normal pressure. The specific process is as follows: the printed object after replacement in step S4 is placed in an oven, and the temperature is increased in the order of 30°C-40°C-50°C-60°C-70°C-80°C, with each temperature maintained for 3 h, to finally obtain a 3D printed organic-inorganic hybrid aerogel.

[0078] Because the evaporation speed of ethanol is fast, the surface tension in the gel cannot be effectively controlled under normal pressure drying, and shrinkage or even collapse occurs, resulting in an organic-inorganic hybrid aerogel with a size of 37 mm in length, 35 mm in width, and 6 mm in height, a large shrinkage size, and obvious cracks on the surface. Comparative Example 4

[0079] This comparative example is basically the same as Example 1, except that in step S1, 5 g of water is added. The specific process is as follows: 96 g of bis[3-(trimethoxysilyl)propyl]amine, 64.6 g of ethanol, 5 g of water, 3.76 g of fumed silica, and 18 g of silica aerogel powder are mixed and stirred for 8 h, and then defoaming is performed using a vacuum defoaming machine at a speed of 1000 rpm for 5 min to obtain a sol ink that can be used for printing.

[0080] Because bis[3-(trimethoxysilyl)propyl]amine hydrolyzes and condenses when it comes into contact with water, the ink will gradually solidify within 1 h, and subsequent printing cannot be performed. Comparative Example 5

[0081] This comparative example is basically the same as Example 1, except that step S2 is not performed, and the sol ink prepared in step S1 is directly printed in the air according to the relevant printing parameters of step S3.

[0082] The sol ink cannot complete the autocatalytic gelation reaction without water, and therefore collapses, cannot be solidified, and cannot form a three-dimensional printed structure with self-supporting ability. Comparative Example 6

[0083] The present comparative example is basically identical with Example 1, except that in step S2, no water is added, and the specific process is as follows: 100 ml of ethanol, 1 g of cetyltrimethylammonium bromide are mixed and stirred uniformly, and then placed in an oven to be heated to 40℃.

[0084] The ink printed into the water bath liquid cannot complete the autocatalytic gelation reaction without water, and therefore collapses, cannot solidify, and cannot form a three-dimensional printed structure with self-supporting ability. Comparative Example 7

[0085] The present comparative example is basically identical with Example 1, except that in step S2, the amount of organic solvent is changed, and the specific process is as follows: 20 ml of water, 180 ml of ethanol, 1 g of cetyltrimethylammonium bromide are mixed and stirred uniformly, and then placed in an oven to be heated to 40℃.

[0086] Due to the low water content in the water bath liquid, the ink solidification speed is slow, and it needs to wait for 1.5 h to completely solidify, and due to the influence of the surface tension of the water bath liquid on the ink during the solidification process, a certain degree of diffusion occurs, so the precision of the printed structure is also poor. Comparative Example 8

[0087] The present comparative example is basically identical with Example 1, except that in step S2, the temperature of the water bath liquid is changed, and the specific process is as follows: 100 ml of water, 100 ml of ethanol, 1 g of cetyltrimethylammonium bromide are mixed and stirred uniformly, and then placed in an oven to be cooled to 10℃.

[0088] Due to the low temperature of the water bath liquid, the ink solidification speed is slow, and it needs to wait for 1 h to completely solidify, and due to the influence of the surface tension of the water bath liquid on the ink during the solidification process, a certain degree of diffusion occurs, so the precision of the printed structure is also poor.

[0089] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing examples, or make equivalent substitutions for part or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solution to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for preparing a 3D printed organic-inorganic hybrid aerogel, characterized in that, It comprises the following steps: S1, mixing and stirring amine-based bridged siloxane, organic solvent and thickening agent to obtain sol ink after defoaming; the amine-based bridged siloxane is selected from one or more of bis[3-(trimethoxysilyl)propyl]amine, bis(3-triethoxysilylpropyl)amine, 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane; S2, mixing and stirring water, organic solvent and surfactant to obtain water bath, and heating to a certain temperature; S3, printing the sol ink in step S1 to the water bath in step S2, waiting for it to solidify and form to obtain a printed part; S4, placing the printed part in step S3 in an oven for aging, and cleaning with an organic solvent to remove residual impurities; S5, drying the printed part in step S4 to obtain an organic-inorganic hybrid aerogel.

2. The method for preparing 3D-printed organic-inorganic hybrid aerogels according to claim 1, characterized in that, In step S1, the mass ratio of the amine-based bridged siloxane, the organic solvent and the thickening agent is 100:(10-600):(8-75).

3. The method for preparing 3D printed organic-inorganic hybrid aerogel according to claim 1, characterized in that, In step S1, the thickening agent comprises one or more of fumed silica, silica aerogel powder, carbomer, hydroxyethyl cellulose, polyvinyl alcohol and cellulose nanofiber; in steps S1, S2 and S4, the organic solvent comprises one or more of ethanol, methanol, acetone, n-heptane and n-hexane.

4. The method for preparing 3D printed organic-inorganic hybrid aerogel according to claim 1, characterized in that, In step S2, the volume ratio of water to organic solvent is 1-4, and the addition amount of the surfactant is 0.1-10 g / L.

5. The method of claim 1, wherein the surfactant in step S2 comprises: One or more of cetyltrimethylammonium bromide, sodium dodecyl sulfate, sodium dodecylbenzenesulfonate and benzalkonium chloride.

6. The preparation method of the 3D printed organic-inorganic hybrid aerogel according to claim 1, in step S2, the water bath is heated to 20-60℃.

7. The preparation method of the 3D printed organic-inorganic hybrid aerogel according to claim 1, in step S3, the printing speed is 1-15 mm / s, the X, Y and Z axis moving speeds are all 10-40 mm / s, the extrusion ratio is 0.5-3.0, and the nozzle diameter is 0.1-2 mm.

8. The preparation method of the 3D printed organic-inorganic hybrid aerogel according to claim 1, in step S4, the aging time is 24-48 h, and the aging temperature is 30-60℃.

9. The method of claim 1, wherein the drying in step S5 comprises: Any one of carbon dioxide supercritical fluid drying, ethanol supercritical fluid drying or vacuum freeze drying; The carbon dioxide supercritical fluid drying comprises: first replacing the organic solvent in the printed part with ethanol, then placing it in supercritical carbon dioxide, and drying it at a pressure of 8-20 MPa and a temperature of 35-60℃ for 10-72 h; The ethanol supercritical fluid drying comprises: first replacing the organic solvent in the printed part with ethanol, then drying it at a pressure of 7-12 MPa and a temperature of 245-270℃ for 10-72 h; The vacuum freeze drying comprises: first replacing the organic solvent in the printed part with deionized water, then pre-freezing at a temperature of -80--40℃, and then drying at a vacuum degree of 5-15 Pa and a temperature of -60--20℃ for 24-96 h.

10. An organic-inorganic hybrid aerogel produced by the method of producing a 3D-printed organic-inorganic hybrid aerogel according to any one of claims 1 to 9.

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