Preparation method of elastic bacterial cellulose-based aerogel thermal insulation flower

Abstract

The invention discloses a preparation method of an elastic bacterial cellulose-based aerogel thermal insulation flower, and belongs to the field of general technological processes of processing and burdening. The preparation method comprises the following steps: by taking bacterial cellulose as a raw material, carrying out alkali treatment on the bacterial cellulose, and then carrying out laser engraving and ultrasonic cleaning on the bacterial cellulose to obtain the bacterial cellulose-based wet gel thermal-insulation flower; fully replacing the wet gel thermal insulation flower with ethanol, and drying with supercritical carbon dioxide to obtain the bacterial cellulose-based aerogel thermal insulation flower. And finally, modifying by a chemical vapor deposition method to obtain the elastic bacterial cellulose-based aerogel thermal insulation flower. The aerogel thermal insulation flower prepared by the invention has better compression resilience, moisture penetrability and thermal insulation property, and can be used as a thermal insulation clothing filling material.

Description

Technical Field

[0001] The invention relates to the general process field of processing and batching, and in particular to a method for preparing an elastic bacterial cellulose-based aerogel thermal insulation flower. Background Art

[0002] Aerogel is a kind of ultra-porous three-dimensional nanomaterial obtained by treating wet gel with a special drying method, so that the liquid phase between the gel skeleton is replaced by the gas phase, while the gel skeleton is preserved intact. Its unique microstructure gives aerogel materials excellent properties such as large specific surface area, low density, low thermal conductivity, and high porosity, making it have good application prospects in many fields such as thermal insulation, separation, energy storage, batteries, and aerospace.

[0003] In the current field of thermal insulation, some studies have used aerogel materials as fillers for thermal insulation clothing. However, the aerogel materials in the existing public technology have poor compression resilience, which limits their application in the field of thermal insulation clothing filling. Aerogel materials as clothing fillers need to have good compression resilience to overcome the squeezing force generated by various actions in life. Summary of the invention

[0004] The object of the present invention is to provide a method for preparing an elastic bacterial cellulose-based aerogel thermal insulation flower, which is used to prepare an aerogel with good compression resilience.

[0005] The technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides a method for preparing an elastic bacterial cellulose-based aerogel thermal insulation flower, comprising the following steps: Step 1: soak the flaky bacterial cellulose in a NaOH aqueous solution under heating conditions, and then wash it with water until it is neutral for later use.

[0006] Step 2, using laser cutting technology to carve on the sheet bacterial cellulose treated in step 1, the carving method is as follows: first, budding carving is performed on both sides of the sheet bacterial cellulose, the depth of the budding carving on both sides is the same, the total depth of the two budding carvings is less than the thickness of the sheet bacterial cellulose, and the two budding carvings form square minimum units on both sides of the sheet bacterial cellulose; then, rough carving is performed, the rough carving will completely cut through the sheet bacterial cellulose to cut out wet gel insulation flowers; the single wet gel insulation flower carved out by the rough carving contains 9 minimum units of 3 times 3; the engraved sheet bacterial cellulose is ultrasonically cleaned to obtain the wet gel insulation flower.

[0007] Step 3, fully replacing the wet gel thermal insulation flower obtained in step 2 with anhydrous ethanol; and then using supercritical carbon dioxide drying to obtain the aerogel thermal insulation flower.

[0008] Step 4, modifying the aerogel thermal insulation flower obtained in step 3 by chemical vapor deposition, using a silanization modifier and water as the modifier; coating the surface of the aerogel thermal insulation flower with a rigid hydrophobic layer through a chemical reaction to obtain a bacterial cellulose-based aerogel thermal insulation flower.

[0009] In a specific embodiment, the present invention uses square sheet bacterial cellulose with a thickness of 5 to 15 mm and a side length of 350 to 400 mm as raw material.

[0010] In a specific embodiment, in step 1 of the present invention, a NaOH aqueous solution with a mass fraction of 2% to 8% is used.

[0011] In a specific embodiment, in step 1 of the present invention, oil bath heating is adopted, the oil bath heating temperature is 50-100° C., and the heating time is 200-240 min.

[0012] In a specific embodiment, in step 2 of the present invention, the power of the bud engraving laser cutting is 80~99.9 W, the engraving speed is 13~15 mm / s, the cutting depth is 2~4 mm, and the side length of the minimum unit produced by the bud engraving is 0.625~1.25 mm.

[0013] In a specific embodiment, in step 3 of the present invention, the supercritical carbon dioxide drying time is 6 to 10 h, the temperature of the supercritical carbon dioxide fluid is 40 to 60 °C, and the pressure is 10 to 20 MPa.

[0014] In a specific embodiment, in step 4 of the present invention, the aerogel insulation flower prepared in step 3 and two centrifuge tubes are placed in a dryer, and the centrifuge tubes are respectively filled with 0.8-1.2 mL of silanization modifier and 0.6-0.9 mL of deionized water, and the dryer is placed in a 70°C oven for modification for 4-8 h.

[0015] Furthermore, the silanization modifier of the present invention adopts methyltrimethoxysilane or methyltrichlorosilane or trimethylchlorosilane.

[0016] In a second aspect, the present invention provides a method for applying elastic bacterial cellulose-based aerogel thermal insulation flowers, wherein the elastic bacterial cellulose-based aerogel thermal insulation flowers are used as filling materials for thermal insulation clothing.

[0017] The beneficial effects of the present invention are as follows: the present invention provides a method for preparing an elastic bacterial cellulose-based aerogel thermal insulation flower, wherein the aerogel thermal insulation flower uses bacterial cellulose as a raw material, is subjected to laser engraving and ultrasonic cleaning after alkali treatment, and obtains a bacterial cellulose-based wet gel thermal insulation flower; the wet gel thermal insulation flower is fully ethanol-substituted and then dried by supercritical carbon dioxide to obtain a bacterial cellulose-based aerogel thermal insulation flower; and finally, the wet gel thermal insulation flower is modified by chemical vapor deposition to obtain an elastic bacterial cellulose-based aerogel thermal insulation flower. The aerogel thermal insulation flower prepared by the present invention has good compression resilience, moisture permeability and thermal insulation, and can be used as a filling material for thermal insulation clothing. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Shown is a schematic diagram of the engraving process in step 2 of Example 1 of the present invention.

[0019] Figure 2 Shown is a real picture of the heat-insulating flower prepared in Example 1 of the present invention.

[0020] Figure 3 Shown is a scanning electron microscope image of the bacterial cellulose-based aerogel thermal insulation flower prepared in Example 1 of the present invention.

[0021] Figure 4 Shown is a contact angle diagram of the bacterial cellulose-based aerogel thermal insulation flower prepared in Example 1 of the present invention.

[0022] Figure 5 Shown is a graph showing the mechanical properties test results of the bacterial cellulose-based aerogel thermal insulation flower prepared in Example 1 of the present invention.

[0023] Figure 6 Shown is a data comparison diagram of the moisture permeability experiment of the present invention.

[0024] Figure 7 Shown is a diagram showing the experimental process of the aerogel thermal insulation flower of the present invention from clumping to loosening.

[0025] Figure 8 Shown is a graph showing the infrared thermal experiment results of the vest after filling.

[0026] Fig. 9 Shown are mechanical properties diagrams of three types of aerogel thermal insulation flowers prepared with different silanization modification times according to the present invention.

[0027] Fig.10 Shown are actual pictures of the heat-insulating flowers prepared in Experiment 1 and Experiment 2 of the present invention.

[0028] Fig.11 Shown is a graph showing the results of thermal insulation performance tests of the thermal insulation flowers prepared in Experiments 2 and 3 of the present invention.

[0029] Fig.12Shown is a graph showing the results of the fluffiness test of the heat-insulating flowers prepared in Experiment 2 and Experiment 3 of the present invention.

[0030] Fig.13 Shown is a graph showing the results of the entanglement test of the thermal insulation flowers prepared in Experiment 2 and Experiment 3 of the present invention.

[0031] Fig.14 Shown is a diagram showing the moisture permeability test equipment of the present invention.

[0032] Description of reference numerals: Fig.14 In the middle, glass cover 1, glass cup 2, cloth 3, hygrometer 4. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] The experimental methods used in the examples are all conventional methods unless otherwise specified; the materials, reagents, etc. used can be obtained from commercial sources unless otherwise specified. For example, in the embodiments of the present invention, the sheet bacterial cellulose produced by Hainan Wenchang Baocheng Industry and Trade Co., Ltd. is used as the raw material, and its thickness is controllable between 5 and 15 mm, and the length and width are controllable between 350 and 400 mm. In the present invention, laser engraving is performed on the sheet bacterial cellulose by a special cutting method to obtain a special shape of heat preservation flower. The following embodiment shows a method for preparing a plurality of heat preservation flowers in batches on a sheet of bacterial cellulose at one time.

[0035] Example 1 A method for preparing an elastic bacterial cellulose-based aerogel thermal insulation flower, the method comprising the following steps: Step 1, alkali treatment of bacterial cellulose raw materials: wash square bacterial cellulose (essentially bacterial cellulose hydrogel) with a thickness of 10 mm and a length and width of 400 mm with clean water; then immerse the washed flaky bacterial cellulose in a 4% NaOH aqueous solution by mass, and heat it in an oil bath at 90 ° C for 200 min to fully remove the internal sugars and other impurities, then take out the soaked flaky bacterial cellulose, wash it with deionized water until it is neutral for use.

[0036] Step 2, preparation of wet gel insulation flower: First, use a laser cutting machine to perform 480 equal-division bud engraving on the flaky bacterial cellulose treated in step 1 according to the side length, then turn it over and perform the same bud engraving on the back; the depth of the bud engraving on both sides is the same, and the total depth of the two bud engravings is less than the thickness of the flaky bacterial cellulose, that is, the two bud engravings do not cut through the flaky bacterial cellulose. In this embodiment, the power of the laser cutting machine during the two bud engravings is 99.9W, the engraving speed is 14 mm / s, and the engraving depth is 2.5 mm. The two bud engravings form a square minimum unit on both sides of the flaky bacterial cellulose; in this embodiment, the minimum unit side length is 0.83 mm. After the engraving is completed, a rough engraving is performed in 160 equal-divisions according to the side length. This engraving completely cuts through the flaky bacterial cellulose and cuts out the wet gel insulation flower. During the rough engraving process, the power of the laser cutting machine is 99.9 W and the engraving speed is 14 mm / s.

[0037] like Figure 1 Shown is a schematic diagram of the engraving process in step 2 of Example 1 of the present invention. Figure 1 In the figure, two bud carvings and one rough carving are shown from left to right. The single wet gel insulation flower carved out of the rough carving contains 9 minimum units of 3 by 3.

[0038] Finally, the carved bacterial cellulose flakes were placed in an ultrasonic cleaner for ultrasonic cleaning for 12 min to obtain several wet gel insulation flowers with a height of about 7 mm and a length and width of about 2.5 mm. Figure 2 The figure shows a real picture of the heat preservation flower prepared in Example 1 of the present invention, wherein the left side shows a real picture of the wet gel heat preservation flower, and the right side shows a real picture of the finally prepared aerogel heat preservation flower. It can be seen from the figure that the heat preservation flower prepared in this embodiment has a matrix connected together in the middle, and flower buds extend to both sides. According to calculations, each side of this embodiment has 9 fully extended flower buds.

[0039] Step 3, preparation of aerogel thermal insulation flower: the wet gel thermal insulation flower obtained in step 2 is fully replaced twice with anhydrous ethanol to completely convert the internal water phase into the ethanol phase; then it is dried with supercritical carbon dioxide for 8 hours to obtain the aerogel thermal insulation flower. In this embodiment, the temperature of the supercritical carbon dioxide fluid is 50°C and the pressure is 18 MPa.

[0040] Step 4, chemical vapor deposition modification (silanization modification) of aerogel thermal insulation flowers: the aerogel thermal insulation flowers prepared in step 3 and two small centrifuge tubes were placed in a dryer, each of which contained 1 mL of methyltrimethoxysilane and 0.8 mL of deionized water. The dryer was placed in a 70 °C oven for 6 h. A rigid hydrophobic layer was coated on the surface of the aerogel through chemical reaction to obtain a bacterial cellulose-based aerogel thermal insulation flower with high elasticity. Figure 2The right figure shows the bacterial cellulose-based aerogel thermal insulation flower finally produced in this embodiment.

[0041] like Figure 3 The figure shows a scanning electron microscope image of the bacterial cellulose-based aerogel thermal insulation flower prepared in Example 1 of the present invention. By observing the electron microscope image, it can be seen that the interior of the aerogel thermal insulation flower prepared in this embodiment presents an entangled three-dimensional network structure, which can lock more air, so that the aerogel thermal insulation flower has high thermal insulation properties.

[0042] like Figure 4 The figure shows the contact angle of the bacterial cellulose-based aerogel thermal insulation flower prepared in Example 1 of the present invention. According to the measurement, the contact angle between the surface of the aerogel thermal insulation flower prepared in this example and the water droplets in the air is 150°, indicating that the aerogel thermal insulation flower is hydrophobic and can achieve a waterproof function when used as a filling material for thermal insulation clothing.

[0043] like Figure 5 The figure shows the mechanical properties test results of the bacterial cellulose-based aerogel thermal insulation flower prepared in Example 1 of the present invention. Under 80% strain, it can still recover to 58% of the original after 60 compression cycles. This fully proves that the method of the present invention can prepare an aerogel with good compression resilience.

[0044] In addition, the present invention uses experiments to test the moisture permeability of the aerogel thermal insulation flower of the present invention. Fig.14 The figure shows the moisture permeability test equipment of the present invention. The test equipment includes a glass cover, a glass cup, a cloth, and a hygrometer.

[0045] The experimental process is as follows: first, pure water is heated to boiling and put into a glass cup, and the glass cup is placed on the base of a glass cover; the aerogel heat-insulating flower prepared by the present invention is filled into a cloth, the cloth covers the top opening of the glass cup and is tightened with a rubber band; the glass cup is covered with a glass cover, and a hygrometer is placed in the glass cover to measure the humidity in the glass cover.

[0046] Comparative experiment: Pure bacterial cellulose blocks and down were filled into cloth respectively and fixed to the top opening of a glass, and the same moisture permeability experiment was carried out.

[0047] Experimental phenomenon and conclusion: The moisture permeability of the sample can be determined by observing the speed at which the water mist appears on the glass cover and the changes in the readings of the hygrometer inside the glass cover. Figure 6 Shown is a data comparison diagram of the moisture permeability experiment of the present invention. Figure 6 The middle curve graph represents the change in the hygrometer reading over time; in the figure, TIAFs represents the aerogel insulation flower experiment of the present invention, Down represents the down experiment, and BC Aerogel block represents the pure bacterial cellulose block experiment. Figure 6The three right pictures in the middle show three groups of experimental phenomena after 10 seconds of closure. The phenomenon of the moisture permeability experiment is: after the aerogel thermal insulation flower of the present invention covers the glass cup, the water vapor generated on the glass cover is faster and more than that of the other two materials, and the hygrometer reading is larger, which proves that the elastic bacterial cellulose-based thermal insulation flower prepared by the present invention has good moisture permeability and is suitable for serving as a filler for thermal insulation clothing.

[0048] Furthermore, the present invention puts the aerogel heat-insulating flowers into a transparent sealed bag, and holds the aerogel heat-insulating flowers together by hand, thereby simulating the clumping phenomenon of clothing fillers; and then studies whether they can be restored to a loose state by patting. Figure 7 The figure shows the experimental process of the aerogel heat-insulating flower from agglomeration to looseness. The experiment proves that the aerogel heat-insulating flower of the present invention can be restored from agglomeration to looseness as a filler, so that the clothing can be restored to a fluffy state after being compressed and deformed, thereby ensuring that the clothing has a good heat-insulating effect.

[0049] Finally, the invention fills the prepared aerogel thermal insulation flower into a vest, and takes infrared thermal imaging photos of it and the down vest in a low temperature environment. Figure 8 As shown, Figure 8 The figure shows the infrared thermal test results of the vest after filling. Figure 8 As shown in the figure, the thickness of the filled vest of the present invention is 2.2 cm, while the thickness of the down vest for comparison is 3 cm; when the thickness is 8 mm thinner than the down vest, the surface temperature of the aerogel thermal insulation flower vest of the present invention is 6°C lower than that of the down vest, which further verifies the high thermal insulation property of the thermal insulation flower of the present invention and proves that the thermal insulation flower of the present invention can be applied to the field of thermal insulation clothing. Example 2

[0050] A method for preparing an elastic bacterial cellulose-based aerogel thermal insulation flower, the method comprising the following steps: Step 1, alkali treatment of bacterial cellulose raw materials: wash large-sized bacterial cellulose with a thickness of 5 mm and a length and width of 400 mm with clean water for 3 times; then immerse the washed flaky bacterial cellulose in a 2% NaOH aqueous solution, and heat it in an oil bath at 50 ° C for 200 min, then take out the soaked flaky bacterial cellulose, wash it with deionized water until it is neutral for use.

[0051] Step 2, preparation of wet gel insulation flower: First, use a laser cutting machine to perform 320-point bud carving on the cleaned flaky bacterial cellulose according to the side length, then turn it over and perform the same bud carving on the back; during the two bud carving processes, the power of the laser cutting machine is 80 W, the carving speed is 15 mm / s, the carving depth is 2 mm, and the minimum unit width of the carving is 1.25 mm. After the carving is completed, the rough carving is performed in 160 points according to the side length. This carving should completely cut through the flaky bacterial cellulose. The power of the laser cutting machine is 99.9 W and the carving speed is 14 mm / s. Finally, the engraved bacterial cellulose is placed in an ultrasonic cleaner for ultrasonic cleaning for 10 min to obtain a bacterial cellulose-based wet gel insulation flower with a height of 3.5 mm, a length and a width of 2.5 mm. At this time, the insulation flower has 4 fully extended flower buds on both sides, and the middle connecting part is the bacterial cellulose matrix.

[0052] Step 3, preparation of aerogel thermal insulation flower: the wet gel thermal insulation flower obtained in step 2 is fully replaced once with anhydrous ethanol to completely convert the internal water phase into the ethanol phase; then it is dried with supercritical carbon dioxide for 6 hours to obtain the bacterial cellulose-based aerogel thermal insulation flower; wherein the temperature of the supercritical carbon dioxide fluid is 40°C and the pressure is 10 MPa.

[0053] Step 4, chemical vapor deposition modification (silanization modification) of bacterial cellulose-based aerogel thermal insulation flower: the aerogel thermal insulation flower prepared in step 3 and two small centrifuge tubes are placed in a dryer, the centrifuge tubes are respectively filled with 0.8 mL of methyltrimethoxysilane and 0.6 mL of deionized water, and the dryer is placed in a 70 °C oven for modification for 4 h. A rigid hydrophobic layer is coated on the surface of the prepared bacterial cellulose-based aerogel through chemical reaction to obtain a bacterial cellulose-based aerogel thermal insulation flower with high elasticity.

[0054] The elastic bacterial cellulose-based aerogel thermal insulation flower prepared in this embodiment can still recover to 51% of the original strain after 60 compression cycles under 80% strain, and the water contact angle is 140°. Example 3

[0055] A method for preparing an elastic bacterial cellulose-based aerogel thermal insulation flower, the method comprising the following steps: Step 1, alkali treatment of bacterial cellulose raw materials: wash the large-sized bacterial cellulose with a thickness of 15 mm and a length and width of 400 mm with clean water; then immerse the washed flaky bacterial cellulose in an 8% NaOH aqueous solution, and heat it in an oil bath at a constant temperature of 100°C for 240 min, then take out the soaked flaky bacterial cellulose, and wash it with deionized water until it is neutral for use.

[0056] Step 2, preparation of wet gel insulation flower: First, use a laser cutting machine to perform 640 equal-division bud engraving on the washed bacterial cellulose sheet in step 1 according to the side length, then turn it over and perform the same bud engraving on the back. At this time, the power of the laser cutting machine is 99.9 W, the engraving speed is 13 mm / s, the engraving depth is 3.5 mm, and the minimum unit width of the engraving is 0.625 mm. After the engraving is completed, the back is roughly engraved in 160 equal-divisions according to the side length, and this engraving should completely cut through the bacterial cellulose sheet. At this time, the power of the laser cutting machine is 99.9 W and the engraving speed is 14 mm / s. Finally, the engraved bacterial cellulose is placed in an ultrasonic cleaner for ultrasonic cleaning for 15 min to obtain a bacterial cellulose-based wet gel insulation flower with a height of 9 mm, a length and a width of 2.5 mm. At this time, the insulation flower has 16 fully extended flower buds on both sides, and the middle connecting part is the bacterial cellulose matrix.

[0057] Step 3, preparation of bacterial cellulose-based aerogel thermal insulation flower: the wet gel thermal insulation flower obtained in step 2 is fully replaced with anhydrous ethanol three times to completely convert the internal water phase into the ethanol phase, and then dried with supercritical carbon dioxide for 10 h to obtain the bacterial cellulose-based aerogel thermal insulation flower; wherein the temperature of the supercritical carbon dioxide fluid is 60°C and the pressure is 20MPa.

[0058] Step 4, chemical vapor deposition modification (silanization modification) of bacterial cellulose-based aerogel thermal insulation flower: the aerogel thermal insulation flower obtained in step 3 and two small centrifuge tubes are placed in a dryer, the centrifuge tubes are respectively filled with 1.2 mL of methyltrimethoxysilane and 0.9 mL of deionized water, the dryer is placed in a 70 °C oven for modification for 8 h, and a rigid hydrophobic layer is coated on the surface of the prepared bacterial cellulose-based aerogel through chemical reaction to obtain a bacterial cellulose-based aerogel thermal insulation flower with high elasticity.

[0059] The elastic bacterial cellulose-based aerogel thermal insulation flower prepared in this embodiment can still recover to 56% of the original strain after 60 compression cycles under 80% strain, and the water contact angle is 145°.

[0060] Other embodiments are shown in the following table Equal fractions of bud carving Laser cutting machine power (W) Laser cutting machine speed (mm / s) Minimum unit width (mm) Supercritical temperature (℃) Supercritical pressure (MPa) Example 4 320 99.9 13 1.25 40 10 Example 5 480 99.9 14 0.83 45 15 Example 6 640 99.9 15 0.625 50 17 Example 7 320 99.9 13 1.25 55 18 Example 8 480 99.9 14 0.83 60 19 Example 9 640 99.0 15 0.625 60 20 In order to verify the effects of different silanization modification time, bud carving equal division degree and speed on the performance of the prepared bacterial cellulose-based aerogel insulation flower, the present invention further carried out the following single variable experiment. Experiment 1

[0061] This experiment is to study the effect of different silanization modification times on the mechanical properties of the prepared aerogel thermal insulation flower. This experiment is based on the method of Example 1, and the silanization modification time is changed to 4 h and 8 h, respectively, and compared with the thermal insulation flower prepared for 6 h in Example 1. The present invention tests the mechanical properties of the three prepared aerogel thermal insulation flowers, and the test results are as follows Fig. 9 As shown, Fig. 9 The figure shows the mechanical properties of three aerogel thermal insulation flowers prepared with different silanization modification times of the present invention. It can be seen from the figure that with the extension of the modification time, the mechanical properties of the prepared aerogel thermal insulation flower are improved, but too long a modification time will increase the brittleness of the aerogel thermal insulation flower. Therefore, the preferred silanization modification time of the present invention is 4-8 h. Experiment 2

[0062] This experiment is to study the effects of different bud carving methods on the thermal insulation performance and fluffiness of the prepared aerogel thermal insulation flower. This experiment adopts the method of Example 1, and changes the bud carving method to divide the side length into 320, 480 and 640 equal parts, and finally performs a rough carving of 160 equal parts. Experiment 3

[0063] This experiment is to study the effect of different bud opening and engraving speeds on the thermal insulation performance and fluffiness of the prepared aerogel thermal insulation flower. This experiment adopts the method of Example 1, changes the bud opening and engraving speed to 13 mm / s, 14 mm / s and 15 mm / s, and finally performs 160 equal divisions of rough engraving. The power of the rough division engraving laser engraving machine remains unchanged, and the speed is uniformly 14 mm / s.

[0064] like Fig.10 Shown are actual pictures of the heat-insulating flowers prepared in Experiment 1 and Experiment 2 of the present invention.

[0065] The present invention tested the thermal insulation performance of different elastic bacterial cellulose-based aerogels prepared in Experiment 2 and Experiment 3. The present invention packaged them with common cloth on the market as packaging materials, then placed them on a cold source at -40 ℃ and photographed them using an infrared imaging camera. The test results are shown in Figure 2. Fig.11 As shown, Fig.11 The figure shows the results of the thermal insulation performance test of the thermal insulation flowers prepared in Experiment 2 and Experiment 3 of the present invention. It can be seen from the figure that when the bud carving is divided into 480 equal parts and the carving speed is 14 mm / s, the thermal insulation performance of the bacterial cellulose-based aerogel thermal insulation flower is the best.

[0066] Furthermore, the present invention tested the fluffiness of the different elastic bacterial cellulose-based aerogel thermal insulation flowers prepared in Experiment 2 and Experiment 3. The test method is: take the same mass of bacterial cellulose-based aerogel thermal insulation flowers and put them into glass bottles of the same size to observe their height. The results are as follows: Fig.12 As shown, Fig.12 The figure shows the results of the fluffy test of the heat-insulating flowers prepared in Experiment 2 and Experiment 3 of the present invention. It can be seen from the figure that the elastic bacterial cellulose-based heat-insulating flowers prepared by carving buds into 480 equal parts and carving at a speed of 14 mm / s have the best fluffyness.

[0067] Furthermore, the present invention tested the entanglement degree of different elastic bacterial cellulose-based aerogel thermal insulation flowers prepared in Experiment 2 and Experiment 3. The test method is: the present invention stacks the prepared elastic bacterial cellulose-based aerogel thermal insulation flowers, then picks them up with tweezers, and determines the entanglement degree by observing the number of thermal insulation flowers connected to them. The test results are as follows: Fig.13 As shown, Fig.13 The figure shows the results of the entanglement test of the heat preservation flowers prepared in Experiment 2 and Experiment 3 of the present invention. It can be seen from the figure that the elastic bacterial cellulose-based heat preservation flower prepared by carving buds into 480 equal parts and carving at a speed of 14 mm / s has the highest entanglement degree.

[0068] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.

Claims

1. A method for preparing an elastic bacterial cellulose-based aerogel thermal insulation flower, characterized in that: The steps include: Step 1, soaking the flaky bacterial cellulose in a NaOH aqueous solution under heating conditions, and then washing with water until it is neutral for later use; Step 2, using laser cutting technology to carve on the sheet bacterial cellulose treated in step 1, the carving method is as follows: first, budding carving is performed on both sides of the sheet bacterial cellulose, the depth of the budding carving on both sides is the same, the total depth of the two budding carvings is less than the thickness of the sheet bacterial cellulose, and the two budding carvings form square minimum units on both sides of the sheet bacterial cellulose; then, rough carving is performed, and the rough carving completely cuts through the sheet bacterial cellulose to cut out wet gel insulation flowers; a single wet gel insulation flower carved out by rough carving contains 9 minimum units of 3 times 3; the carved sheet bacterial cellulose is ultrasonically cleaned to obtain a wet gel insulation flower; Step 3, fully replacing the wet gel thermal insulation flower obtained in step 2 with anhydrous ethanol; and then drying with supercritical carbon dioxide to obtain the aerogel thermal insulation flower; Step 4, modifying the aerogel thermal insulation flower obtained in step 3 by chemical vapor deposition, using a silanization modifier and water as the modifier; coating the surface of the aerogel thermal insulation flower with a rigid hydrophobic layer through a chemical reaction to obtain a bacterial cellulose-based aerogel thermal insulation flower.

2. The method for preparing the elastic bacterial cellulose-based aerogel thermal insulation flower according to claim 1, characterized in that: Square sheets of bacterial cellulose with a thickness of 5-15 mm and a side length of 350-400 mm were used.

3. The method for preparing the elastic bacterial cellulose-based aerogel thermal insulation flower according to claim 1, characterized in that: In step 1, a NaOH aqueous solution with a mass fraction of 2% to 8% is used.

4. The method for preparing the elastic bacterial cellulose-based aerogel thermal insulation flower according to claim 1, characterized in that: In step 1, oil bath heating is adopted, the oil bath heating temperature is 50-100°C, and the heating time is 200-240 min.

5. The method for preparing the elastic bacterial cellulose-based aerogel thermal insulation flower according to claim 1, characterized in that: In step 2, the power of the bud engraving laser cutting is 80~99.9 W, the engraving speed is 13~15 mm / s, the cutting depth is 2~4 mm, and the side length of the minimum unit produced by the bud engraving is 0.625~1.25 mm.

6. The method for preparing the elastic bacterial cellulose-based aerogel thermal insulation flower according to claim 1, characterized in that: In step 3, the supercritical carbon dioxide drying time is 6 to 10 h, the temperature of the supercritical carbon dioxide fluid is 40 to 60 °C, and the pressure is 10 to 20 MPa.

7. The method for preparing the elastic bacterial cellulose-based aerogel thermal insulation flower according to claim 1, characterized in that: In step 4, the aerogel insulation flower prepared in step 3 and two centrifuge tubes are placed in a desiccator, each of which is filled with 0.8-1.2 mL of silanization modifier and 0.6-0.9 mL of deionized water. The desiccator is placed in a 70°C oven for modification for 4-8 h.

8. The method for preparing the elastic bacterial cellulose-based aerogel thermal insulation flower according to claim 1, characterized in that: The silanization modifier is methyltrimethoxysilane, methyltrichlorosilane or trimethylchlorosilane.

9. A method for using elastic bacterial cellulose-based aerogel thermal insulation flowers, characterized in that: Elastic bacterial cellulose-based aerogel thermal insulation flowers are used as filling materials for thermal insulation clothing.

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