Preparation Method of Bionic Gel Material and Its Flame Retardant and Anti-Icing Properties

Abstract

The present invention provides a preparation method of a biomimetic aerogel material, comprising the following steps: A) Based on the melting characteristics of fatty alcohol sensitive to temperature, the mechanism of forming a conjugate structure between bisphenol A and 2-phenylamino-3-methyl-6-dibutylaminofluorane is regulated, and a temperature-sensitive color-changing capsule is synthesized; B) Using bio-based sodium alginate and sodium phytate as the aerogel framework, boron nitride nanosheets and temperature-sensitive color-changing capsules as fillers, a fireproof and photothermal deicing aerogel material is prepared by directional freeze-drying method. Water is used as the solvent in the synthesis process, which is green and environmentally friendly. By regulating the appearance of the aerogel through the temperature-sensitive color-changing capsule, sunlight is reflected in a high-temperature environment and absorbed and converted in a low-temperature environment, thus effectively suppressing the problems of summer light aging and winter low-temperature icing. Sodium alginate, sodium phytate, and boron nitride nanosheets jointly endow the aerogel with good flame retardant and fireproof properties.

Description

Technical Field

[0001] The present invention relates to the technical field of materials, and in particular to a preparation method of a bionic gel material and its flame retardant and anti-icing properties. Background Art

[0002] The normal operation of infrastructure and industrial equipment is closely related to people's lives. However, extreme working conditions caused by some adverse weather can cause operation failures of infrastructure and industrial equipment. For example, the intense sunlight exposure in hot summers can keep equipment in a continuous high-temperature state, resulting in equipment failure, material aging, and even fire accidents. On the contrary, the low temperature in severe winters often leads to icing problems of outdoor facilities and equipment, such as power cables, high-speed trains, and wind turbine blades. Once a large amount of ice freezes and accumulates, it will inevitably lead to equipment collapse and overload. Therefore, it is very urgent and challenging to develop a material that can increase or reflect solar energy in winter and summer respectively, achieve intelligent temperature control, and at the same time have fire prevention and anti-icing properties to solve the fire and icing problems of infrastructure and industrial equipment under extreme working conditions. Summary of the Invention

[0003] In view of this, the technical problem to be solved by the present invention is to provide a preparation method of a bionic gel material, and the prepared bionic gel material has good thermochromic, anti-icing, and flame retardant and fire prevention properties.

[0004] The present invention provides a preparation method of a bionic gel material, comprising the following steps:

[0005] A) Bisphenol A, 2-phenylamino-3-methyl-6-dibutylamino fluoran, and fatty alcohol are added to an aqueous solution, and a surfactant is added, and stirred to obtain an oil-in-water emulsion;

[0006] B) A melamine formaldehyde resin prepolymer is dropped into the oil-in-water emulsion for microencapsulation to obtain thermochromic microcapsules;

[0007] C) Boron nitride nanosheets, sodium alginate, sodium phytate, and thermochromic microcapsules are respectively added to an aqueous solution, and mixed to obtain a mixed system;

[0008] D) The mixed system is directionally freeze-dried and dried to obtain an aerogel material;

[0009] E) A polydimethylsiloxane precursor is sprayed on the surface of the composite aerogel to obtain the bionic gel material.

[0010] Preferably, the mass ratio of bisphenol A, 2-phenylamino-3-methyl-6-dibutylamino fluoran, and fatty alcohol is 1:(1-3):(95-98).

[0011] Preferably, the fatty alcohol is a mixture of n-decanol and dodecanol; the mass ratio of n-decanol is 10% - 100%.

[0012] Preferably, the surfactant is sodium dodecyl sulfonate; the mass concentration of the sodium dodecyl sulfonate is 0.3% - 3%.

[0013] Preferably, the stirring is mechanical stirring, the speed of the stirring is 3000 r / min; the stirring time is 60 min.

[0014] Preferably, the preparation method of the melamine formaldehyde resin prepolymer in step B) is specifically: mixing melamine with a formaldehyde solution to react to form a melamine resin prepolymer; the melamine resin prepolymer is formed under the condition of pH 8.5.

[0015] Preferably, the microencapsulation reaction time in step B) is 1 - 6 h, the temperature is 30 - 60 °C; the pH value of the microencapsulation reaction system is 4 - 6.

[0016] Preferably, in step C),

[0017] The mass ratio of boron nitride nanosheets, sodium alginate, sodium phytate, and thermochromic microcapsules is 10:10:(1 - 3):(1 - 5);

[0018] Preferably, it is specifically one of 10:10:3:5, 10:10:2:4, 10:10:1:1, or 10:10:3:3

[0019] The concentration of the boron nitride nanosheets is 5.0 g / L.

[0020] Preferably, step D) is specifically:

[0021] Pouring the mixed system into a polytetrafluoroethylene mold, placing it on the surface of a copper sheet after low-temperature treatment with liquid nitrogen for directional freeze-drying, and then vacuum drying to obtain an aerogel material;

[0022] The time of the directional freeze-drying is 0.5 - 1 h; the drying is at -20 °C for 48 h.

[0023] The present invention provides a bionic gel material prepared by the preparation method described in any one of the above technical solutions.

[0024] Compared with the prior art, the present invention provides a method for preparing an artificial aerogel material, comprising the following steps: A) Based on the temperature-sensitive melting characteristics of fatty alcohols, the mechanism of forming a conjugated structure between bisphenol A and 2-phenylamino-3-methyl-6-dibutylamino fluorane is regulated, and a thermochromic capsule is synthesized; B) Using bio-based sodium alginate and sodium phytate as the aerogel framework, boron nitride nanosheets and thermochromic capsules as fillers, a fireproof and photothermal deicing aerogel material is prepared by directional freeze-drying. Water is used as the solvent in the synthesis process, which is green and environmentally friendly. By regulating the appearance of the aerogel through thermochromic capsules, sunlight is reflected in high-temperature environments and absorbed and converted in low-temperature environments, thus effectively suppressing the problems of summer light aging and winter low-temperature icing. Sodium alginate, sodium phytate, and boron nitride nanosheets jointly endow the aerogel with good flame retardant and fireproof properties. Description of the Drawings

[0025] Figure 1 Figure Figure 1 is the SEM spectrum of the thermochromic microcapsules prepared in Example 1 of the present invention, indicating that the thermochromic capsules have a good spherical morphology;

[0026] Figure 2 Figures Figure 2 are the top view (a) and cross-sectional view (b) SEM photos of the prepared composite aerogel. Figure 2 It shows that due to the presence of the temperature field, ice crystals grow along the vertical growth direction. Therefore, the upper surface skeleton is an irregular structure, and the cross-sectional skeleton is a parallel structure;

[0027] Figure 3 Figure Figure 3 is the color change of the composite aerogel during liquid nitrogen treatment: the composite aerogel turns black as the temperature decreases. In contrast, the color of the composite aerogel without thermochromic capsules does not change;

[0028] Figure 4 Figure Figure 4 is the digital photo of the change of the ice melting phenomenon on the surface of the composite aerogel over time. It is found that under the action of light, the composite aerogel exhibits a photothermal conversion effect, so the ice crystals melt and then slide off;

[0029] Figure 5 Figure Figure 5 are the curves of the heat release rate (a) and total heat release amount (b) of the composite aerogel. It is found that compared with the composite aerogel without boron nitride nanosheets, the heat release rate and total heat release amount of the composite aerogel are reduced from 164.6 kW / m 2 and 15.4 MJ / m 2 to 48.4 kW / m 2 and 6.4 MJ / m 2 .

[0030] Figure 6This is the fire resistance test of the composite aerogel: The composite aerogel without boron nitride addition (Figure a) was ignited at 15 s and the paper above was ignited; in contrast, the composite aerogel (Figure b) did not show intense combustion, and the paper above was not ignited, indicating significant flame retardant and fire prevention properties. Detailed implementation manners

[0031] The present invention provides a preparation method of a bionic gel material and research on its flame retardant and anti-icing properties. Those skilled in the art can draw on the content of this article and appropriately modify the process parameters to achieve it. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art, and they all fall within the protection scope of the present invention. The method and application of the present invention have been described through preferred embodiments, and those related can obviously make changes or appropriate modifications and combinations to the method and application in this article without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention.

[0032] The terms "comprising", "including" and "having" can be used interchangeably herein, aiming to represent the inclusiveness of the solution, meaning that the solution may have other elements in addition to the listed elements. At the same time, it should be understood that when using "comprising", "including" and "having" to describe in this article, the solution of "consisting of..." is also provided.

[0033] It should be understood that in various embodiments of the present application, the magnitudes of the serial numbers of the following processes do not mean the sequence of execution. Some or all steps can be executed in parallel or sequentially, and the execution sequence of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0034] The aerogel prepared by the present invention has a high solar reflectance and infrared emissivity, and can reflect sunlight in the hot summer to reduce the surface temperature of the material. At the same time, the thermochromic microcapsules can endow the aerogel material with a photothermal conversion function at low temperatures to inhibit the icing problem. The cone calorimeter and fire resistance test confirm that the aerogel material has excellent flame retardant and fire prevention properties.

[0035] The thermochromic microcapsules in the present invention can show a dynamic response to the ambient temperature, have good temperature control switching ability, and achieve intelligent adjustment. The present invention uses sodium phytate and sodium alginate as the aerogel skeleton, and adds thermochromic microcapsules and boron nitride nanosheets to endow the aerogel with good thermochromic, anti-icing, flame retardant and fire prevention properties.

[0036] The preparation method of the biomimetic aerogel material with fire prevention and de-icing functions uses bisphenol A, 2-phenylamino-3-methyl-6-dibutylamino fluorane, and fatty alcohol as the thermochromic core material, melamine and formaldehyde resin as the thermochromic shell material, sodium phytate and sodium alginate as the aerogel skeleton, and boron nitride nanosheets are added at the same time to obtain a multifunctional composite aerogel material.

[0037] The present invention provides a preparation method of a biomimetic gel material, which includes the following steps:

[0038] A) Bisphenol A, 2-phenylamino-3-methyl-6-dibutylamino fluorane, and fatty alcohol are added to an aqueous solution, a surfactant is added, and stirring is carried out to obtain an oil-water emulsion;

[0039] B) The melamine formaldehyde resin prepolymer is dropped into the oil-water emulsion for microencapsulation to obtain thermochromic microcapsules;

[0040] C) Boron nitride nanosheets, sodium alginate, sodium phytate, and thermochromic microcapsules are respectively added to an aqueous solution, and mixing is carried out to obtain a mixed system;

[0041] D) The mixed system is directionally freeze-dried and dried to obtain an aerogel material;

[0042] E) The polydimethylsiloxane precursor is sprayed on the surface of the composite aerogel to obtain the biomimetic gel material.

[0043] For the biomimetic gel material provided by the present invention, first, bisphenol A, 2-phenylamino-3-methyl-6-dibutylamino fluorane, and fatty alcohol are added to an aqueous solution, a surfactant is added, and stirring is carried out to obtain an oil-water emulsion.

[0044] According to the present invention, the mass ratio of bisphenol A, 2-phenylamino-3-methyl-6-dibutylamino fluorane, and fatty alcohol is 1:(1-3):(95-98);

[0045] In one preferred embodiment of the present invention, the mass ratio of bisphenol A, 2-phenylamino-3-methyl-6-dibutylamino fluorane, and fatty alcohol is 1:1:98;

[0046] In one preferred embodiment of the present invention, the mass ratio of bisphenol A, 2-phenylamino-3-methyl-6-dibutylamino fluorane, and fatty alcohol is 2:1:97;

[0047] In one preferred embodiment of the present invention, the mass ratio of bisphenol A, 2-phenylamino-3-methyl-6-dibutylamino fluorane, and fatty alcohol is 3:2:95;

[0048] In one preferred embodiment of the present invention, the mass ratio of bisphenol A, 2-phenylamino-3-methyl-6-dibutylaminofluorane, and fatty alcohol is 2:3:95.

[0049] The fatty alcohol in the present invention is a mixture of n-decanol and dodecanol; among them, the mass ratio of n-decanol is 10% - 100%; preferably 20% - 90%; more preferably 30% - 80%; most preferably 40% - 70%.

[0050] According to the present invention, the surfactant is sodium dodecyl sulfate; the mass concentration of the sodium dodecyl sulfate is preferably 0.3% - 3%; more preferably 0.3% - 2.7%.

[0051] The stirring in the present invention is mechanical stirring. The present invention does not limit the specific parameters of the mechanical stirring, and those well-known to those skilled in the art can be used. The speed of the stirring is 3000 r / min; the stirring time is 1 - 6 h.

[0052] The melamine formaldehyde resin prepolymer is dropped into the oil-water emulsion for microencapsulation to obtain the thermochromic microcapsules.

[0053] First, prepare the melamine formaldehyde resin prepolymer.

[0054] The specific method for preparing the melamine formaldehyde resin prepolymer in the present invention is as follows:

[0055] Mix melamine with formaldehyde solution and react to form a melamine resin prepolymer; the melamine resin prepolymer is formed under the condition that the pH is 4 - 6. The present invention preferably uses acetic acid to adjust the pH value.

[0056] Among them, the melamine formaldehyde resin prepolymer is dropped into the oil-water emulsion for microencapsulation, and then vacuum filtration is carried out; the microencapsulation reaction time is 1 - 6 h, and the temperature is 30 - 60 °C; the dropping is slow dropping; the pH value of the microencapsulation reaction system is 4 - 6; preferably, acetic acid is used to adjust the pH value of the system.

[0057] The present invention does not limit the vacuum filtration, and those well-known to those skilled in the art can be used.

[0058] Add boron nitride nanosheets, sodium alginate, sodium phytate, and thermochromic microcapsules into an aqueous solution respectively, and mix to obtain a mixed system; the mixing is preferably ultrasonic stirring mixing, and the time of the ultrasonic stirring is preferably 50 - 70 min; more preferably 1 h.

[0059] In a preferred embodiment of the present invention, the mass ratio of the boron nitride nanosheets, sodium alginate, sodium phytate, and thermochromic microcapsules is 10:10:(1 - 3):(1 - 5);

[0060] In one specific embodiment, the mass ratio of the boron nitride nanosheets, sodium alginate, sodium phytate, and thermochromic microcapsules is 10:10:3:5;

[0061] In one specific embodiment, the mass ratio of the boron nitride nanosheets, sodium alginate, sodium phytate, and thermochromic microcapsules is 10:10:2:4;

[0062] In one specific embodiment, the mass ratio of the boron nitride nanosheets, sodium alginate, sodium phytate, and thermochromic microcapsules is 10:10:1:1;

[0063] In one specific embodiment, the mass ratio of the boron nitride nanosheets, sodium alginate, sodium phytate, and thermochromic microcapsules is 10:10:3:3;

[0064] The concentration of the boron nitride nanosheets in the present invention is 5.0 g / L.

[0065] The mixed system is directionally freeze-dried and dried to obtain an aerogel material;

[0066] Step D) of the present invention is specifically as follows:

[0067] The mixed system is poured into a polytetrafluoroethylene mold, placed for directional freeze-drying and drying, and directionally freeze-dried on the surface of a copper sheet after low-temperature treatment with liquid nitrogen, and then vacuum-dried to obtain an aerogel material.

[0068] More preferably specifically: The mixed system is added to a polytetrafluoroethylene mold, and the mold is placed on the surface of a copper sheet, while the copper sheet is cooled with liquid nitrogen. After the dispersion system is frozen at low temperature, it is dried in a freeze dryer.

[0069] The time for the directional freeze-drying in the present invention is 0.5 - 1 h;

[0070] The polydimethylsiloxane precursor is sprayed on the surface of the composite aerogel, and then dried to obtain a biomimetic gel material.

[0071] The amount of the polydimethylsiloxane precursor used in the present invention is 10 wt% of the total mass of the aerogel; the drying is carried out at 80 °C for 2 h.

[0072] The present invention provides a biomimetic gel material prepared by the preparation method described in any one of the above technical solutions.

[0073] The present invention has clearly described the above preparation method, and will not be elaborated herein.

[0074] The present invention uses bisphenol A, 2-phenylamino-3-methyl-6-dibutylaminofluoran, and fatty alcohol as the temperature-sensitive color-changing core material, and melamine formaldehyde resin as the temperature-sensitive color-changing shell material to synthesize temperature-sensitive color-changing microcapsules. Combining boron nitride nanosheets, sodium alginate, and sodium phytate, a bio-based composite aerogel is prepared by directional freezing. The prepared aerogel has a high solar reflectance and infrared emissivity. The results of photothermal and de-icing tests show that the material has excellent reflection / absorption intelligent conversion ability and anti-de-icing effect. The cone calorimeter and fire protection tests confirm that the material has excellent flame retardant and fire protection properties.

[0075] Compared with the existing technologies, the beneficial effects of the present invention are as follows: The raw materials used in the present invention are easy to obtain, the process is simple, easy to operate, and easy to synthesize. The composite aerogel obtained by the present invention can reflect sunlight in hot summer, reducing the surface temperature of the material; the composite aerogel obtained by the present invention can absorb sunlight in cold winter, increasing the surface temperature of the material and inhibiting the risk of icing. The composite aerogel obtained by the present invention exhibits good flame retardant and fire protection properties.

[0076] To further illustrate the present invention, the following provides a detailed description of a bionic gel material, its preparation method, and a method for removing organic pollutants in water according to the present invention in combination with embodiments.

[0077] Example 1

[0078] (1) Bisphenol A, 2-phenylamino-3-methyl-6-dibutylaminofluoran, and fatty alcohol are added to an aqueous solution in a mass ratio of 1:2:97. At the same time, the fatty alcohol is a mixture of n-decyl alcohol and dodecyl alcohol, and the mass ratio of n-decyl alcohol is 56%;

[0079] (2) 0.33 g of sodium dodecyl sulfate surfactant is added to the above aqueous solution, and mechanical stirring (3000 r / min) is carried out for 60 min to form a stable oil-water emulsion for standby;

[0080] (3) Melamine is mixed with 37% formaldehyde solution, and the pH value of the system is adjusted to 8.5 with ammonia water to form a melamine resin prepolymer for standby;

[0081] (4) The prepolymer system in step 3 is slowly dropped into the emulsion in step 2, and the pH value of the system is adjusted to 4 with acetic acid to start microencapsulation. After 6 h, the synthetic product, i.e., thermochromic microcapsules, is collected by vacuum filtration;

[0082] (5) 1.0 g of boron nitride nanosheets, 1.0 g of sodium alginate, 0.3 g of sodium phytate, and 0.5 g of temperature-sensitive color-changing microcapsules are respectively added to 200 mL of aqueous solution, and ultrasonic stirring is carried out for 1 h to obtain a well-dispersed suspension;

[0083] (6) Place a copper sheet into liquid nitrogen to obtain extremely low temperature, and then place the polytetrafluoroethylene mold containing the composite aerogel precursor solution on the surface of the copper sheet for 30 min, and completely freeze-dry it.

[0084] (7) Spray 0.3 g of polydimethylsiloxane precursor on the surface of the dried composite aerogel, and heat it at 80 °C for 2 h to finally prepare the composite aerogel.

[0085] Figure 1 It is the SEM spectrum of the thermochromic microcapsules prepared in Example 1 of the present invention, indicating that the thermochromic capsules have a good spherical morphology.

[0086] Figure 2 It is the top view (a) and cross-sectional view (b) SEM photos of the composite aerogel prepared in Example 1 of the present invention. Figure 2 It shows that due to the existence of the temperature field, ice crystals grow along the vertical growth direction. Therefore, the upper surface skeleton is an irregular structure, and at the same time, the cross-sectional skeleton is a parallel structure.

[0087] Figure 3 It is the thermal imaging diagram of the composite aerogel in Example 1 of the present invention at room temperature and one sunlight intensity, indicating that at 1.0 kW / m 2 the surface temperature of the aerogel is 49.8 °C.

[0088] Figure 4 It is the thermal imaging diagram of the composite aerogel in Example 1 of the present invention at -10 °C and one sunlight intensity, indicating that at 1.0 kW / m 2 the surface temperature of the aerogel is 16.9 °C.

[0089] Figure 5 It is the digital photo of the change of the ice melting phenomenon on the surface of the composite aerogel with time in Example 1 of the present invention. It is found that under the action of light, the composite aerogel exhibits a photothermal conversion effect, so the ice crystals melt and then slide off after 240 s.

[0090] Figure 6 It is the curves of the heat release rate (a) and the total heat release amount (b) of the composite aerogels in Example 1 and Comparative Example 3. It is found that compared with Comparative Example 3, the heat release rate and the total heat release amount of the composite aerogel in the example are respectively reduced from 164.6 kW / m 2 and 15.4 MJ / m 2 to 48.4 kW / m 2 and 6.4 MJ / m 2 .

[0091] Comparative Example 1 (1) Bisphenol A, 2-phenylamino-3-methyl-6-dibutylaminofluorane, and fatty alcohol were added to an aqueous solution in a mass ratio of 1:1:98. At the same time, the fatty alcohol was a mixture of n-decanol and dodecanol, and the mass ratio of n-decanol was 56%;

[0092] (2) 0.33 g of sodium dodecyl sulfate surfactant was added to the above aqueous solution, and mechanically stirred (3000 r / min) for 60 min to form a stable oil-in-water emulsion for standby;

[0093] (3) Melamine was mixed with 37% formaldehyde solution, and the pH value of the system was adjusted to 8.5 with ammonia water to form a melamine resin prepolymer for standby;

[0094] (4) The prepolymer system in step 3 was slowly dropped into the emulsion in step 2, and the pH value of the system was adjusted to 5 with acetic acid to start microencapsulation. After 3 h, the synthesized product, i.e., thermochromic microcapsules, was collected by vacuum filtration;

[0095] (5) 1.0 g of boron nitride nanosheets, 1.0 g of sodium alginate, 0.2 g of sodium phytate, and 0.4 g of thermosensitive color-changing microcapsules were respectively added to 200 mL of aqueous solution, and ultrasonically stirred for 1 h to obtain a well-dispersed suspension;

[0096] (6) A copper sheet was placed in liquid nitrogen to obtain an extremely low temperature, and then a polytetrafluoroethylene mold containing a composite aerogel precursor solution was placed on the surface of the copper sheet for 30 min and completely freeze-dried;

[0097] (7) 0.3 g of polydimethylsiloxane precursor was sprayed on the surface of the dried composite aerogel, and heated at 80 °C for 2 h to finally prepare the composite aerogel.

[0098] Comparative Example 2

[0099] (1) Bisphenol A, 2-phenylamino-3-methyl-6-dibutylaminofluorane, and fatty alcohol were added to an aqueous solution in a mass ratio of 2:3:95. At the same time, the fatty alcohol was a mixture of n-decanol and dodecanol, and the mass ratio of n-decanol was 56%;

[0100] (2) 0.33 g of sodium dodecyl sulfate surfactant was added to the above aqueous solution, and mechanically stirred (3000 r / min) for 60 min to form a stable oil-in-water emulsion for standby;

[0101] (3) Melamine was mixed with 37% formaldehyde solution, and the pH value of the system was adjusted to 8.5 with ammonia water to form a melamine resin prepolymer for standby;

[0102] (4) Slowly drop the prepolymer system in step 3 into the emulsion in step 2, adjust the pH value of the system to 6 with acetic acid, and start microencapsulation. After 1 h, collect the synthesized product, i.e., the thermochromic microcapsules, by vacuum filtration;

[0103] (5) Add 1.0 g of boron nitride nanosheets, 1.0 g of sodium alginate, 0.3 g of sodium phytate, and 0.3 g of thermosensitive color-changing microcapsules into 200 mL of aqueous solution respectively, and ultrasonically stir for 1 h to obtain a well-dispersed suspension;

[0104] (6) Place a copper sheet in liquid nitrogen to obtain an extremely low temperature, then place the polytetrafluoroethylene mold containing the composite aerogel precursor solution on the surface of the copper sheet for 30 min, and completely freeze-dry;

[0105] (7) Spray 0.3 g of polydimethylsiloxane precursor on the surface of the dried composite aerogel, and heat it at 80 °C for 2 h to finally prepare the composite aerogel.

[0106] Comparative Example 3

[0107] (1) Add bisphenol A, 2-phenylamino-3-methyl-6-dibutylaminofluorane, and fatty alcohol into the aqueous solution according to a mass ratio of 1:2:97. At the same time, the fatty alcohol is a mixture of n-decanol and dodecanol, and the mass ratio of n-decanol is 56%;

[0108] (2) Add 0.33 g of sodium dodecyl sulfate surfactant into the above aqueous solution, and mechanically stir (3000 r / min) for 60 min to form a stable oil-in-water emulsion for standby;

[0109] (3) Mix melamine with 37% formaldehyde solution, and adjust the pH value of the system to 8.5 with ammonia water to form a melamine resin prepolymer for standby;

[0110] (4) Slowly drop the prepolymer system in step 3 into the emulsion in step 2, adjust the pH value of the system to 4 with acetic acid, and start microencapsulation. After 6 h, collect the synthesized product, i.e., the thermochromic microcapsules, by vacuum filtration;

[0111] (5) Add 1.0 g of sodium alginate, 0.3 g of sodium phytate, and 0.5 g of thermosensitive color-changing microcapsules into 200 mL of aqueous solution respectively, and ultrasonically stir for 1 h to obtain a well-dispersed suspension;

[0112] (6) Place a copper sheet in liquid nitrogen to obtain an extremely low temperature, then place the polytetrafluoroethylene mold containing the composite aerogel precursor solution on the surface of the copper sheet for 30 min, and completely freeze-dry;

[0113] (7) Spray 0.3 g of polydimethylsiloxane precursor on the surface of the dried composite aerogel, and heat it at 80 °C for 2 h to finally prepare the composite aerogel.

[0114] Table 1 shows the data comparison between Example 1 and Comparative Examples 1, 2, and 3. Among them, Surface Temperature 1 is the surface temperature of the aerogel at -10°C and a certain solar irradiance, Surface Temperature 2 is the surface temperature of the aerogel at room temperature and a certain solar irradiance, the ice sliding time is the time for the ice on the surface to slide due to the photothermal conversion of the aerogel at -10°C and a certain solar irradiance, and both the peak heat release rate and the total heat release amount are measured by a cone calorimeter.

[0115] Table 1

[0116]

[0117] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A preparation method of a bionic gel material, characterized in that, It includes the following steps: A) Bisphenol A, 2-phenylamino-3-methyl-6-dibutylamino fluoran, and fatty alcohol are added to an aqueous solution, and a surfactant is added, followed by stirring to obtain an oil-water emulsion; the mass ratio of bisphenol A, 2-phenylamino-3-methyl-6-dibutylamino fluoran, and fatty alcohol is 1:(1 - 3):(95 - 98); B) The melamine formaldehyde resin prepolymer is dropped into the oil-water emulsion for microencapsulation to obtain thermochromic microcapsules; C) Boron nitride nanosheets, sodium alginate, sodium phytate, and thermochromic microcapsules are respectively added to an aqueous solution and mixed to obtain a mixed system; the mass ratio of boron nitride nanosheets, sodium alginate, sodium phytate, and thermochromic microcapsules is 10:10:3:5; D) The mixed system is directionally freeze-dried and dried to obtain an aerogel material; E) A polydimethylsiloxane precursor is sprayed on the surface of the composite aerogel to obtain a biomimetic gel material.

2. The preparation method according to claim 1, characterized in that, The fatty alcohol is a mixture of n-decanol and dodecanol; the mass ratio of n-decanol is 20% - 90%.

3. The preparation method according to claim 1, wherein, The surfactant is sodium dodecyl sulfate; the mass concentration of sodium dodecyl sulfate is 0.3% - 3%.

4. The preparation method according to claim 1, characterized in that, The stirring is mechanical stirring, the stirring speed is 3000 r / min; the stirring time is 60 min.

5. The preparation method according to claim 1, wherein, The preparation method of the melamine formaldehyde resin prepolymer in step B) is specifically as follows: Melamine is mixed with a formaldehyde solution and reacted to form a melamine resin prepolymer; the melamine resin prepolymer is formed under the condition of pH 8.

5.

6. The preparation method according to claim 1, wherein, In step B), the microencapsulation reaction time is 1 to 6 h, the temperature is 30 to 60 o °C; the pH value of the microencapsulation reaction system is 4 to 6.

7. The preparation method according to claim 1, characterized in that Step C) The concentration of the boron nitride nanosheets is 5.0 g / L.

8. The preparation method according to claim 1, wherein Step D) is specifically as follows: The mixed system is poured into a polytetrafluoroethylene mold and placed on the surface of a copper sheet after low-temperature treatment with liquid nitrogen, followed by directional freeze-drying and vacuum drying to obtain an aerogel material; The time for the directional freeze-drying is 0.5 - 1 h; the drying is vacuum drying at -20°C for 48 h.

9. A bionic gel material, characterized in that, Prepared by the preparation method according to any one of claims 1 - 8.

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