Preparation method of an 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, belonging to the field of general technological processes of processing and batching; the aerogel thermal insulation flower uses bacterial cellulose as a raw material, which is subjected to alkali treatment, laser engraving and ultrasonic cleaning to obtain a bacterial cellulose-based wet gel thermal insulation flower; after the wet gel thermal insulation flower is fully replaced with ethanol, it is dried by supercritical carbon dioxide to obtain a bacterial cellulose-based aerogel thermal insulation flower; finally, it 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 invention has good compression resilience, moisture permeability and heat preservation performance, and can be used as a filling material for thermal insulation clothing.

Description

Technical Field

[0001] The present invention relates to the general process fields of processing and batching, and particularly relates to a preparation method of an elastic bacterial cellulose-based aerogel thermal insulation flower. Background Art

[0002] An aerogel is a super-porous three-dimensional nanomaterial obtained by treating a wet gel with a special drying method, so that the liquid phase between the gel skeletons is replaced by a gas phase, while the gel skeletons are well preserved. Its unique microstructure endows the aerogel material with excellent properties such as a 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 technologies have poor compression resilience, which limits their application in the field of thermal insulation clothing filling. As a filler for clothing, the aerogel material needs to have good compression resilience to overcome the squeezing force generated by various movements in life. Summary of the Invention

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

[0005] The technical solution adopted by the present invention is as follows:

[0006] In the first aspect, the present invention provides a preparation method of an elastic bacterial cellulose-based aerogel thermal insulation flower, including the following steps:

[0007] Step 1, soak the sheet-shaped bacterial cellulose with an NaOH aqueous solution under heating conditions, and then wash it with water until it is neutral for standby.

[0008] Step 2, engrave on the sheet-shaped bacterial cellulose processed in Step 1 using laser cutting technology. The engraving method is as follows: First, perform budding engraving on both sides of the sheet-shaped bacterial cellulose. The depths of the budding engraving on both sides are the same. The total depth of the two budding engravings is less than the thickness of the sheet-shaped bacterial cellulose. The two budding engravings form a square minimum unit on both sides of the sheet-shaped bacterial cellulose; then perform rough division engraving. The rough division engraving completely cuts through the sheet-shaped bacterial cellulose to cut out a wet gel thermal insulation flower; each single wet gel thermal insulation flower cut out by the rough division engraving contains 9 minimum units in a 3 by 3 arrangement; ultrasonically clean the engraved sheet-shaped bacterial cellulose to obtain a wet gel thermal insulation flower.

[0009] Step 3, fully displace the wet gel thermal insulation flower prepared in Step 2 with absolute ethanol; then obtain an aerogel thermal insulation flower by supercritical carbon dioxide drying.

[0010] Step 4: Modify the aerogel heat-insulating flower prepared in Step 3 by chemical vapor deposition. The modifiers used are silanization modifiers and water; a rigid hydrophobic layer is coated on the surface of the aerogel heat-insulating flower through a chemical reaction to obtain a bacterial cellulose-based aerogel heat-insulating flower.

[0011] In a specific embodiment, the present invention uses square sheet-shaped bacterial cellulose with a thickness of 5 - 15 mm and a side length of 350 - 400 mm as the raw material.

[0012] In a specific embodiment, in Step 1 of the present invention, an aqueous NaOH solution with a mass fraction of 2% - 8% is used.

[0013] In a specific embodiment, in Step 1 of the present invention, oil bath heating is used. The oil bath heating temperature is 50 - 100 °C, and the heating time is 200 - 240 min.

[0014] In a specific embodiment, in Step 2 of the present invention, the power of the budding 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 smallest unit generated by the budding engraving is 0.625 - 1.25 mm.

[0015] In a specific embodiment, in Step 3 of the present invention, the supercritical carbon dioxide drying time is 6 - 10 h, the temperature of the supercritical carbon dioxide fluid is 40 - 60 °C, and the pressure is 10 - 20 MPa.

[0016] In a specific embodiment, in Step 4 of the present invention, the aerogel heat-insulating flower prepared in Step 3 and two centrifuge tubes are placed in a dryer. The centrifuge tubes are respectively filled with 0.8 - 1.2 mL of silanization modifier and 0.6 - 0.9 mL of deionized water. The dryer is placed in an oven at 70 °C for modification for 4 - 8 h.

[0017] Furthermore, the silanization modifier used in the present invention is methyltrimethoxysilane or methyltrichlorosilane or trimethylchlorosilane.

[0018] In the second aspect, the present invention provides a method for applying an elastic bacterial cellulose-based aerogel heat-insulating flower, using the elastic bacterial cellulose-based aerogel heat-insulating flower as a heat-insulating clothing filling material.

[0019] 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. The aerogel thermal insulation flower uses bacterial cellulose as a raw material, which is subjected to alkali treatment, laser engraving, and ultrasonic cleaning to obtain a bacterial cellulose-based wet gel thermal insulation flower; after the wet gel thermal insulation flower is fully replaced with ethanol, it is dried by supercritical carbon dioxide to obtain a bacterial cellulose-based aerogel thermal insulation flower; finally, it 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 heat preservation performance, and can be used as a filling material for thermal insulation clothing. Description of the Drawings

[0020] Figure 1 The schematic diagram of the engraving process in step 2 of Example 1 of the present invention is shown.

[0021] Figure 2 The physical picture of the thermal insulation flower prepared in Example 1 of the present invention is shown.

[0022] Figure 3 The scanning electron microscope picture of the bacterial cellulose-based aerogel thermal insulation flower prepared in Example 1 of the present invention is shown.

[0023] Figure 4 The contact angle picture of the bacterial cellulose-based aerogel thermal insulation flower prepared in Example 1 of the present invention is shown.

[0024] Figure 5 The mechanical property test result picture of the bacterial cellulose-based aerogel thermal insulation flower prepared in Example 1 of the present invention is shown.

[0025] Figure 6 The data comparison picture of the moisture permeability experiment of the present invention is shown.

[0026] Figure 7 The experimental process display picture of the aerogel thermal insulation flower of the present invention from agglomeration to loosening is shown.

[0027] Figure 8 The infrared thermal imaging experimental result display picture after the vest of the present invention is filled is shown.

[0028] Figure 9 The mechanical property pictures of three kinds of aerogel thermal insulation flowers prepared with different silanization modification times of the present invention are shown.

[0029] Figure 10 The physical pictures of the thermal insulation flowers prepared in Experiment 1 and Experiment 2 of the present invention are shown.

[0030] Figure 11 The result display picture of the thermal insulation performance test of the thermal insulation flowers prepared in Experiment 2 and Experiment 3 of the present invention is shown.

[0031] Figure 12The figure shows the result display diagram of the bulkiness test of the thermal insulation flowers prepared in Experiment 2 and Experiment 3 of the present invention.

[0032] Figure 13 The figure shows the result display diagram of the entanglement degree test of the thermal insulation flowers prepared in Experiment 2 and Experiment 3 of the present invention.

[0033] Figure 14 The figure shows the display diagram of the moisture permeability experimental equipment of the present invention.

[0034] Explanation of reference numerals: Figure 14 In the figure, glass cover 1, glass cup 2, fabric 3, hygrometer 4. Specific implementation manners

[0035] The technical solutions in the embodiments of the present invention will be described clearly and completely below. Apparently, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0036] Unless otherwise specified, the experimental methods used in the embodiments are all conventional methods; the materials, reagents, etc. used, unless otherwise specified, can all be obtained from commercial channels. For example, in the embodiments of the present invention, the sheet-shaped bacterial cellulose produced by Hainan Wenchang Baocheng Industry and Trade Co., Ltd. is used as the raw material, and its thickness can be controlled between 5 and 15 mm, and its length and width can be controlled between 350 and 400 mm. In the present invention, laser engraving is performed on the sheet-shaped bacterial cellulose by a special cutting method to obtain thermal insulation flowers with special shapes. The following embodiments show a method for batch preparing multiple thermal insulation flowers at one time on a sheet of sheet-shaped bacterial cellulose.

[0037] Embodiment 1

[0038] A preparation method of an elastic bacterial cellulose-based aerogel thermal insulation flower, the method comprising the following steps:

[0039] Step 1, alkali treatment of the bacterial cellulose raw material: Wash a square bacterial cellulose (essentially a bacterial cellulose hydrogel) with a thickness of 10 mm and a length and width of 400 mm with clean water; then immerse the washed sheet-shaped bacterial cellulose in an aqueous solution of 4% NaOH by mass, and heat it in an oil bath at 90 °C for 200 min under constant temperature to fully remove the internal sugars and other impurities. Subsequently, take out the soaked sheet-shaped bacterial cellulose and wash it with deionized water until it is neutral for standby.

[0040] Step 2, Preparation of wet gel heat-insulating flowers: First, use a laser cutting machine to perform budding engraving on the sheet-shaped bacterial cellulose processed in Step 1 at 480 equal parts according to the side length, then turn it over and perform the same budding engraving on the back; the depths of budding engraving on both sides are the same, and the total depth of the two budding engravings is less than the thickness of the sheet-shaped bacterial cellulose, that is, the two budding engravings do not cut through the sheet-shaped bacterial cellulose. In this embodiment, during the two budding engraving processes, the power of the laser cutting machine is 99.9 W, the engraving speed is 14 mm / s, and the engraving depth is 2.5 mm. The two budding engravings form square minimum units on both sides of the sheet-shaped bacterial cellulose; in this embodiment, the side length of the minimum unit is 0.83 mm. After engraving, perform rough engraving at 160 equal parts according to the side length. This engraving cuts through the sheet-shaped bacterial cellulose completely to cut out wet gel heat-insulating flowers. During the rough engraving process, the power of the laser cutting machine is 99.9 W and the engraving speed is 14 mm / s.

[0041] As Figure 1 shown is the schematic diagram of the engraving process in Step 2 of Embodiment 1 of the present invention. Figure 1 Among them, the two budding engravings and one rough engraving are respectively shown from left to right. Each single wet gel heat-insulating flower cut out by the rough engraving contains a total of 9 minimum units of 3 by 3.

[0042] Finally, put the engraved sheet-shaped bacterial cellulose into an ultrasonic cleaner and ultrasonically clean it for 12 min to obtain a number of wet gel heat-insulating flowers with a height of about 7 mm and a length and width of about 2.5 mm. As Figure 2 shown is the physical picture of the heat-insulating flower prepared in Embodiment 1 of the present invention. The physical picture of the wet gel heat-insulating flower is on the left side, and the physical picture of the finally obtained aerogel heat-insulating flower is on the right side. It can be seen from the figure that the middle of the heat-insulating flower prepared in this embodiment is a matrix connected together, and flower buds extend out to both sides. After measurement, each side of this embodiment has 9 fully extended flower buds.

[0043] Step 3, Preparation of aerogel heat-insulating flowers: Replace the wet gel heat-insulating flowers prepared in Step 2 with absolute ethanol twice to completely convert the internal water phase into an ethanol phase; then perform supercritical carbon dioxide drying for 8 h to obtain aerogel heat-insulating flowers. In this embodiment, the temperature of the supercritical carbon dioxide fluid is 50 °C and the pressure is 18 MPa.

[0044] Step 4, Modification of aerogel heat-insulating flowers by chemical vapor deposition (silylation modification): Put the aerogel heat-insulating flowers prepared in Step 3 and two small centrifuge tubes into a dryer. The centrifuge tubes are respectively filled with 1 mL of methyltrimethoxysilane and 0.8 mL of deionized water. Place the dryer in an oven at 70 °C for modification for 6 h, and coat a rigid hydrophobic layer on the surface of the aerogel through a chemical reaction to obtain a highly elastic bacterial cellulose-based aerogel heat-insulating flower. As Figure 2The final prepared bacterial cellulose-based aerogel thermal insulation flower of this embodiment is shown in the right figure.

[0045] As Figure 3 shown is the 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 intertwined three-dimensional network structure, which can lock more air, making the aerogel thermal insulation flower have high thermal insulation properties.

[0046] As Figure 4 shown is the contact angle image of the bacterial cellulose-based aerogel thermal insulation flower prepared in Example 1 of the present invention. After measurement, the contact angle between the surface of the aerogel thermal insulation flower prepared in this embodiment and the water droplet in the air is 150 °, indicating that the aerogel thermal insulation flower has hydrophobicity and can achieve a waterproof function when used as a filling material for thermal insulation clothing.

[0047] As Figure 5 shown is the test result image of the mechanical properties of the bacterial cellulose-based aerogel thermal insulation flower prepared in Example 1 of the present invention. At 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.

[0048] In addition, the present invention experimentally tested the moisture permeability of the aerogel thermal insulation flower of the present invention. As Figure 14 shown is the display image of the moisture permeability experimental equipment of the present invention. The experimental equipment includes a glass cover, a glass cup, a cloth, and a hygrometer.

[0049] The experimental process is as follows: First, heat pure water to boiling and pour it into the glass cup, and place it on the base of the glass cover; fill the aerogel thermal insulation flower prepared by the present invention into the cloth, cover the top opening of the glass cup with the cloth and tighten it with a rubber band; cover the glass cup with the glass cover, and place the hygrometer in the glass cover to measure the humidity inside the glass cover.

[0050] Comparative experiment: Fill pure bacterial cellulose blocks and down into the cloth respectively, and fix them at the top opening of the glass cup in the same way for the same moisture permeability experiment.

[0051] Experimental phenomena and conclusions: The moisture permeability of the sample is judged by observing the appearance speed of the water mist on the glass cover and the change of the hygrometer reading inside the glass cover. As Figure 6 shown is the data comparison image of the moisture permeability experiment of the present invention. Figure 6 The curve in the figure represents the change value of the hygrometer reading with time; in the figure, TIAFs represents the experiment of the aerogel thermal insulation flower of the present invention, Down represents the down experiment, and BC Aerogel block represents the pure bacterial cellulose block experiment. Figure 6The three figures on the right show the experimental phenomenon display diagrams of three groups after being closed for 10 s. The experimental phenomenon of moisture permeability is as follows: After the aerogel thermal insulation flower of the present invention covers the glass, the water vapor generated on the glass cover is faster and more than that of the other two materials, and the reading of the hygrometer is larger, which proves that the elastic bacterial cellulose-based aerogel thermal insulation flower prepared by the present invention has good moisture permeability and is suitable as the filler of thermal insulation clothing.

[0052] Furthermore, the present invention puts the aerogel thermal insulation flower into a transparent sealed bag, and unites the aerogel thermal insulation flower together by hand to simulate the phenomenon of the filler of clothing agglomerating; then studies whether it can return to the loose state by patting. As Figure 7 shown is the experimental process display diagram of the aerogel thermal insulation flower of the present invention from agglomerating to loosening. The experiment proves that the aerogel thermal insulation flower of the present invention can recover from agglomerating to loosening as a filler, which can ensure that the clothing can recover to a fluffy state after being deformed under pressure, so as to ensure that the clothing has a good thermal insulation effect.

[0053] Finally, the prepared aerogel thermal insulation flower of the present invention is filled into a vest, and infrared thermal imaging is taken of it and a down vest in a low-temperature environment. The experimental results are as Figure 8 shown, Figure 8 shown is the experimental result display diagram of the infrared thermal imaging of the vest filled with the present invention. As Figure 8 shown, the thickness of the vest filled with the present invention is 2.2 cm, and the thickness of the compared down vest is 3 cm; in the case that 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, further verifying the high thermal insulation of the thermal insulation flower of the present invention and proving that the thermal insulation flower of the present invention can be applied to the field of thermal insulation clothing. Example 2

[0054] A preparation method of an elastic bacterial cellulose-based aerogel thermal insulation flower, the method comprising the following steps:

[0055] Step 1, alkali treatment of bacterial cellulose raw materials: Wash the large-size bacterial cellulose with a thickness of 5 mm and a length and width of 400 mm three times with clean water; then immerse the washed sheet-shaped bacterial cellulose in a 2% NaOH aqueous solution, and heat it at a constant temperature of 50 °C for 200 min with an oil bath, and then fish out the soaked sheet-shaped bacterial cellulose and wash it with deionized water until it is neutral for standby.

[0056] Step 2, Preparation of wet gel flower: First, use a laser cutting machine to perform budding engraving on the washed sheet-shaped bacterial cellulose by dividing it into 320 equal parts according to the side length. Then turn it over and perform the same budding engraving on the back. During the two budding engraving processes, the power of the laser cutting machine is 80 W, the engraving speed is 15 mm / s, the engraving depth is 2 mm, and the width of the smallest engraving unit is 1.25 mm. After engraving, perform rough engraving by dividing it into 160 equal parts according to the side length. This engraving should completely cut through the sheet-shaped bacterial cellulose. The power of the laser cutting machine is 99.9 W, and the engraving speed is 14 mm / s. Finally, put the engraved bacterial cellulose into an ultrasonic cleaner and ultrasonically clean it for 10 min to obtain a bacterial cellulose-based wet gel flower with a height of 3.5 mm, a length and width of 2.5 mm. At this time, the morphology of the flower is that there are 4 fully extended flower buds on each of the front and back sides, and the middle connecting part is the bacterial cellulose matrix.

[0057] Step 3, Preparation of aerogel flower: Replace the wet gel flower prepared in Step 2 with absolute ethanol once to completely convert the internal water phase into an ethanol phase. Then perform supercritical carbon dioxide drying for 6 h to obtain a bacterial cellulose-based aerogel flower. The temperature of the supercritical carbon dioxide fluid is 40 °C and the pressure is 10 MPa.

[0058] Step 4, Modification of bacterial cellulose-based aerogel flower by chemical vapor deposition (silylation modification): Put the aerogel flower prepared in Step 3 and two small centrifuge tubes into a dryer. The centrifuge tubes are respectively filled with 0.8 mL of methyltrimethoxysilane and 0.6 mL of deionized water. Place the dryer in an oven at 70 °C for modification for 4 h. A rigid hydrophobic layer is coated on the surface of the prepared bacterial cellulose-based aerogel through a chemical reaction to obtain a highly elastic bacterial cellulose-based aerogel flower.

[0059] The elastic bacterial cellulose-based aerogel flower prepared in this example can still recover to 51% of its original state after 60 compression cycles under a strain of 80%, and the water contact angle is 140 °. Example 3

[0060] A preparation method of an elastic bacterial cellulose-based aerogel flower, the method comprising the following steps:

[0061] Step 1, Alkaline treatment of bacterial cellulose raw material: Wash the large-size bacterial cellulose with a thickness of 15 mm and a length and width of 400 mm with clean water. Then immerse the washed sheet-shaped bacterial cellulose in an 8% NaOH aqueous solution and heat it at a constant temperature of 100 °C for 240 min in an oil bath. Then take out the soaked sheet-shaped bacterial cellulose and wash it with deionized water until it is neutral for standby.

[0062] Step 2, Preparation of wet gel flower: First, use a laser cutting machine to perform budding engraving on the washed sheet-shaped bacterial cellulose in step 1 by dividing it into 640 equal parts according to the side length. Then turn it over and perform the same budding 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 width of the smallest engraving unit is 0.625 mm. After engraving, perform rough engraving on the back by dividing it into 160 equal parts according to the side length, and this time the engraving should completely cut through the sheet-shaped bacterial cellulose. At this time, the power of the laser cutting machine is 99.9 W, and the engraving speed is 14 mm / s. Finally, put the engraved bacterial cellulose into an ultrasonic cleaner and ultrasonically clean it for 15 min to obtain a bacterial cellulose-based wet gel flower with a height of 9 mm and a length and width of 2.5 mm. At this time, the morphology of the flower is that there are 16 fully extended flower buds on each of the front and back sides, and the middle connecting part is the bacterial cellulose matrix.

[0063] Step 3, Preparation of bacterial cellulose-based aerogel flower: Replace the wet gel flower prepared in step 2 with anhydrous ethanol three times to completely convert the internal water phase into an ethanol phase, and then use supercritical carbon dioxide drying for 10 h to obtain a bacterial cellulose-based aerogel flower; the temperature of the supercritical carbon dioxide fluid is 60 °C and the pressure is 20 MPa.

[0064] Step 4, Modification of bacterial cellulose-based aerogel flower by chemical vapor deposition (silylation modification): Put the aerogel flower obtained in step 3 and two small centrifuge tubes into a dryer. The centrifuge tubes are respectively filled with 1.2 mL of methyltrimethoxysilane and 0.9 mL of deionized water. Place the dryer in an oven at 70 °C for modification for 8 h, and coat a rigid hydrophobic layer on the surface of the prepared bacterial cellulose-based aerogel through a chemical reaction to obtain a highly elastic bacterial cellulose-based aerogel flower.

[0065] The elastic bacterial cellulose-based aerogel flower prepared in this example can still recover to 56% of its original state after 60 compression cycles at 80% strain, and the water contact angle is 145 °.

[0066] Other examples are shown in the following table

[0067] Equal division number of budding carving Power of laser cutting machine (W) Speed of laser cutting machine (mm / s) Width of minimum unit (mm) Supercritical temperature (°C) 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

[0068] To verify the effects of different silylation modification times, budding engraving equal division degrees and speeds on the performance of the prepared bacterial cellulose-based aerogel flower, the present invention further carried out the following single-variable experiments.

[0069] Experiment 1

[0070] This experiment was conducted to study the effect of different silanization modification times on the mechanical properties of the prepared aerogel heat-preserving flowers. Based on the method of Example 1, the silanization modification times were changed to 4 h and 8 h respectively, and compared with the heat-preserving flowers prepared in 6 h in Example 1. The present invention tested the mechanical properties of the three prepared aerogel heat-preserving flowers, and the test results are as Figure 9 shown, Figure 9 The figure shows the mechanical property diagrams of the three aerogel heat-preserving 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 heat-preserving flowers are improved, but too long modification time will lead to increased brittleness of the aerogel heat-preserving flowers. Therefore, the preferred silanization modification time of the present invention is 4 - 8 h.

[0071] Experiment 2

[0072] This experiment was conducted to study the effect of different bud-opening carving methods on the heat preservation and insulation performance and fluffiness of the prepared aerogel heat-preserving flowers. The method of Example 1 was adopted in this experiment, and the bud-opening carving methods were changed to be divided into 320, 480, and 640 equal parts according to the side length, and finally all were roughly carved into 160 equal parts.

[0073] Experiment 3

[0074] This experiment was conducted to study the effect of different bud-opening carving speeds on the heat preservation and insulation performance and fluffiness of the prepared aerogel heat-preserving flowers. The method of Example 1 was adopted in this experiment, and the bud-opening carving speeds were changed to 13 mm / s, 14 mm / s, and 15 mm / s respectively, and finally all were roughly carved into 160 equal parts. The power of the laser engraving machine for rough carving remained unchanged, and the speed was unified to 14 mm / s.

[0075] As Figure 10 shown is the physical diagram of the heat-preserving flowers prepared in Experiment 1 and Experiment 2 of the present invention.

[0076] The present invention tested the heat preservation and insulation performance of the different elastic bacterial cellulose-based aerogel heat-preserving flowers prepared in Experiment 2 and Experiment 3. The present invention encapsulated them with common ordinary fabrics on the market as packaging materials, and then placed them on a cold source at -40 °C and took pictures of them with an infrared imaging camera. The test results are as Figure 11 shown, Figure 11 The figure shows the result display diagram of the heat preservation and insulation performance test of the heat-preserving flowers prepared in Experiment 2 and Experiment 3 of the present invention. It can be seen from the figure that the bacterial cellulose-based aerogel heat-preserving flower prepared with 480 equal parts of bud-opening carving and a carving speed of 14 mm / s has the best heat preservation and insulation performance.

[0077] Furthermore, the present invention conducted fluffiness tests on different elastic bacterial cellulose-based aerogel thermal insulation flowers prepared in Experiment 2 and Experiment 3. The test method was as follows: Take the bacterial cellulose-based aerogel thermal insulation flowers of the same mass and put them into glass bottles of the same size to observe their height. The results are as Figure 12 shown, Figure 12 shown is the result display diagram of the fluffiness test of the thermal insulation flowers prepared in Experiment 2 and Experiment 3 of the present invention. As can be seen from the figure, the fluffiness of the elastic bacterial cellulose-based aerogel thermal insulation flower prepared with the bud carving divided into 480 equal parts and the carving speed of 14 mm / s is the best.

[0078] Furthermore, the present invention conducted entanglement tests on different elastic bacterial cellulose-based aerogel thermal insulation flowers prepared in Experiment 2 and Experiment 3. The test method was as follows: The prepared elastic bacterial cellulose-based aerogel thermal insulation flowers were stacked and placed, and then picked up with tweezers. The entanglement degree was determined by observing the number of thermal insulation flowers brought along. The test results are as Figure 13 shown, Figure 13 shown is the result display diagram of the entanglement test of the thermal insulation flowers prepared in Experiment 2 and Experiment 3 of the present invention. As can be seen from the figure, the entanglement degree of the elastic bacterial cellulose-based aerogel thermal insulation flower prepared with the bud carving divided into 480 equal parts and the carving speed of 14 mm / s is the highest.

[0079] It can be understood that the present invention is described by means of some embodiments. Those skilled in the art know that without departing from the spirit and scope of the present invention, various changes or equivalent replacements can be made to these features and embodiments. In addition, under the teaching of the present invention, these features and embodiments can be modified to adapt to specific situations 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 belong to the scope protected by the present invention.

Claims

1. A preparation method of an elastic bacterial cellulose-based aerogel thermal insulation flower, characterized in that It includes the following steps: Step 1: Soak the sheet-shaped bacterial cellulose in an aqueous NaOH solution under heating conditions, and then wash it with water until it is neutral for standby; Step 2: Use laser cutting technology to engrave on the sheet-shaped bacterial cellulose processed in Step 1. The engraving method is as follows: First, perform budding engraving on both sides of the sheet-shaped bacterial cellulose. The depths of budding engraving on both sides are the same, and the total depth of the two budding engravings is less than the thickness of the sheet-shaped bacterial cellulose. The two budding engravings form a square minimum unit on both sides of the sheet-shaped bacterial cellulose; then perform rough division engraving. The rough division engraving completely cuts through the sheet-shaped bacterial cellulose to cut out the wet gel heat preservation flower. Each single wet gel heat preservation flower cut out by the rough division engraving contains 9 minimum units in a 3×3 pattern; ultrasonically clean the engraved sheet-shaped bacterial cellulose to obtain the wet gel heat preservation flower; Step 3: Fully displace the wet gel heat preservation flower prepared in Step 2 with absolute ethanol; then obtain the aerogel heat preservation flower by supercritical carbon dioxide drying; Step 4: Modify the aerogel heat preservation flower prepared in Step 3 by chemical vapor deposition. The modifier uses a silylation modifier and water; a rigid hydrophobic layer is coated on the surface of the aerogel heat preservation flower through a chemical reaction to obtain the bacterial cellulose-based aerogel heat preservation flower.

2. The preparation method of the elastic bacterial cellulose-based aerogel heat-insulating flower according to claim 1, characterized in that, Use a square sheet-shaped bacterial cellulose with a thickness of 5 - 15 mm and a side length of 350 - 400 mm.

3. The preparation method of the elastic bacterial cellulose-based aerogel thermal insulation flower according to claim 1, characterized in that, In Step 1, use an aqueous NaOH solution with a mass fraction of 2% - 8%.

4. The preparation method of the elastic bacterial cellulose-based aerogel heat-insulating flower according to claim 1, wherein, In Step 1, use oil bath heating. The oil bath heating temperature is 50 - 100 °C, and the heating time is 200 - 240 min.

5. The preparation method of the elastic bacterial cellulose-based aerogel thermal insulation flower according to claim 1, wherein, In Step 2, the power of the laser cutting for budding engraving 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 generated by the budding engraving is 0.625 - 1.25 mm.

6. The preparation method of 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 - 10 h, the temperature of the supercritical carbon dioxide fluid is 40 - 60 °C, and the pressure is 10 - 20 MPa.

7. The preparation method of the elastic bacterial cellulose-based aerogel thermal insulation flower according to claim 1, characterized in that, In Step 4, put the aerogel heat preservation flower prepared in Step 3 and two centrifuge tubes into a dryer. The centrifuge tubes are respectively filled with 0.8 - 1.2 mL of the silylation modifier and 0.6 - 0.9 mL of deionized water. Place the dryer in an oven at 70 °C for modification for 4 - 8 h.

8. The preparation method of the elastic bacterial cellulose-based aerogel heat-insulating flower according to claim 1, wherein, The silylation modifier uses methyltrimethoxysilane or methyltrichlorosilane or trimethylchlorosilane.

9. A method for applying an elastic bacterial cellulose-based aerogel to keep flowers warm, characterized in that, Use the elastic bacterial cellulose-based aerogel heat preservation flower prepared by the preparation method of the elastic bacterial cellulose-based aerogel heat preservation flower according to any one of claims 1 - 8 as the filling material for thermal insulation clothing.

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