Method for preparing metal hydroxide-cellulose composite and its application in energy-saving package
By preparing metal hydroxide-cellulose composite materials, the problems of temperature and humidity control and antibacterial properties of packaging materials in food storage were solved, achieving energy-saving and environmentally friendly food preservation effects.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- JIANGSU UNIV
- Filing Date
- 2024-11-20
- Publication Date
- 2026-06-09
Smart Images
Figure CN119502472B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of composite material technology, and relates to energy-saving materials, particularly to a method for preparing a metal hydroxide-cellulose composite material and its application in energy-saving packaging. Background Technology
[0002] Currently, most food storage technologies remain energy-intensive and non-energy-efficient, typically employing high-energy-consuming methods such as refrigerators, cold storage, and vacuum storage to extend food shelf life. It is noteworthy that food spoilage caused by excessively high temperature and humidity accounts for a significant proportion of cases. Therefore, regulating food storage temperature and humidity is crucial for reducing energy consumption during food storage and preventing food spoilage.
[0003] Packaging materials refer to materials used in the production and packaging of various items, aiming to ensure greater convenience and safety during the distribution, storage, and transportation of products after production. Most existing packaging materials are made of transparent plastic, but plastic itself is difficult to degrade in the natural environment, and improper disposal after use can cause environmental pollution, lacking environmental protection and energy-saving capabilities. Furthermore, current packaging materials lack temperature and humidity control during food storage, failing to address the high energy consumption issues associated with technologies such as refrigerators, cold storage, and vacuum storage. To reduce the high energy consumption of current food storage technologies and improve the environmental protection and energy-saving characteristics of packaging materials, it is necessary to develop a new type of energy-saving packaging material.
[0004] The energy-saving packaging material prepared by this invention is assembled from composite cellulose and metal hydroxide nanosheets. It has functions of packaging humidity regulation, heat dissipation and antibacterial properties, effectively reducing the use of cold chain preservation equipment and plastic products, and has good application prospects in the field of food preservation. Summary of the Invention
[0005] In view of the shortcomings of the prior art, the first objective of the present invention is to provide a method for preparing a metal hydroxide-cellulose composite material.
[0006] Technical solution
[0007] A method for preparing a metal hydroxide-cellulose composite material includes the following steps:
[0008] a) Prepare a 0.01-0.03 mol / L zinc salt solution, and add hexamethylenetetramine to zinc salt at a molar ratio of 1:1 to 1:3, preferably 1:2, and stir until homogeneous to obtain the precursor reaction solution.
[0009] b) Pour the precursor reaction solution into a polytetrafluoroethylene-lined stainless steel reactor, and press it into biomass fiber.
[0010] Based on a ratio of 50–100 g / L between the aluminum film and the precursor reaction solution, immerse the biomass fiber in the aluminum film and perform a hydrothermal reaction at 60–120°C for 5–10 hours. After cooling and filtration, wash with distilled water 3–6 times, and then at 80–120°C...
[0011] Dry for 12–24 hours to obtain biomass cellulose@metal hydroxide nanosheets;
[0012] c) Prepare a sodium lauryl solution with a concentration of 40–80 g / L. Based on a material ratio of 60–120 g / L between biomass cellulose@metal hydroxide nanosheets and sodium lauryl solution, immerse the biomass cellulose@metal hydroxide nanosheets in the solution.
[0013] Metal hydroxide nanosheets were reacted at 50°C for 4–8 h to obtain hydrophobic biomass cellulose@metal hydroxide nanosheets.
[0014] d) Prepare an electrospinning solution with a molar ratio of acetone to dichloromethane of 1:2 to 1:5, dissolve cellulose acetate in the solution to obtain an electrospinning solution with a concentration of 60 to 100 g / L, and electrospin the solution onto the surface of hydrophobic biomass cellulose@metal hydroxide nanosheets to deposit cellulose acetate, thereby obtaining a metal hydroxide-cellulose composite material.
[0015] In a preferred embodiment of the present invention, the zinc salt in step a) is one or a combination of zinc nitrate, zinc acetate, or zinc chloride.
[0016] In a preferred embodiment of the present invention, the biomass fiber@aluminum membrane described in step b) is a cellulose surface coated with high-purity aluminum or aluminum oxide.
[0017] Furthermore, when the biomass fiber@aluminum film is a cellulose surface coated with high-purity aluminum, it is prepared using magnetron sputtering technology. The specific process is as follows: in a nitrogen atmosphere, an Al target is placed in a magnetron sputtering furnace, the distance between the target and the sample is adjusted to 20-40 mm, the sputtering power is 20-40 W, and the time is 10-20 min, so that Al particles are sputtered onto the surface of the biomass fiber to obtain a biomass fiber@high-purity aluminum film.
[0018] Furthermore, when the biomass fiber@aluminum membrane is cellulose coated with alumina, it is prepared using the sol-gel method. The specific process is as follows: a solution is prepared by mixing anhydrous ethanol and water in a volume ratio of 1:1 to 1:2, aluminum nitrate is added, and acetic acid is used to adjust the pH of the solution to 4 to 5 to prepare an aluminum sol with a concentration of 0.1 to 0.2 mol / L; then the biomass fiber is immersed in the aluminum sol, allowed to stand for 1 to 2 hours, and then dried at 60 to 120°C for 5 to 10 minutes. The immersion-drying process is repeated 5 to 10 times to obtain the biomass fiber@alumina membrane.
[0019] In a preferred embodiment of the present invention, the electrospinning process in step d) has the following parameters: ambient temperature of 10–30°C, relative humidity of 20–40%, electrospinning solution flow rate of 0.06–0.09 mL / min, and distance between needle and collector of 10–15 cm.
[0020] The second objective of this invention is to provide a metal hydroxide-cellulose composite material prepared according to the above method, which is assembled from composite cellulose and metal hydroxide nanosheets, wherein the composite cellulose is composed of biomass cellulose and cellulose acetate, and the metal hydroxide nanosheets are dispersed on the surface of the biomass cellulose.
[0021] The biomass cellulose has a diameter of 10–40 μm; the cellulose acetate has a diameter of 20–60 μm; and the metal hydroxide nanosheets have a size of 300–800 nm.
[0022] Furthermore, the metal hydroxide-cellulose composite material is composed of a hydrophilic cellulose acetate layer and a hydrophobic biomass cellulose@metal hydroxide nanosheet layer, and has asymmetric infrared radiation properties and asymmetric wetting properties.
[0023] The hydrophilic cellulose acetate layer has a thickness of 100–200 μm, a reflectivity of not less than 80%, and a water contact angle of not more than 40°; the hydrophobic biomass cellulose@metal hydroxide nanosheet layer has a thickness of 500–800 μm, an emissivity of not less than 90%, and a water contact angle of not less than 120°.
[0024] The present invention also discloses the application of the prepared metal hydroxide-cellulose composite material in energy-saving packaging materials.
[0025] Beneficial effects
[0026] The metal hydroxide-cellulose composite material prepared in this invention, composed of composite cellulose, offers advantages such as low cost, safety, and environmental friendliness when used as an energy-saving packaging material. It effectively reduces the use of plastic packaging products. It possesses asymmetric infrared radiation properties, effectively lowering the internal temperature of the packaging and reducing the need for cold chain equipment. It also features directional liquid transfer capabilities, regulating the humidity inside the packaging to mitigate food spoilage caused by excessive humidity and extend food shelf life. By fully utilizing the unique layered structure, metal ion release, positive charge adsorption, and active oxygen release properties of metal hydroxides, it is grown in situ on the cellulose surface, resulting in an energy-saving packaging material with excellent antibacterial properties. This energy-saving packaging material has functions of humidity control, heat dissipation, and antibacterial properties, and can be used for the preservation packaging of fresh food and other raw materials. Attached Figure Description
[0027] Figure 1Scanning electron microscope images of biomass cellulose, where (a) is cellulose from agricultural waste, (b) is cellulose from waste paper, and (c) is cellulose from waste packaging.
[0028] Figure 2 Scanning electron microscope images of biomass cellulose@aluminum membrane, where (d) is biomass cellulose@high-purity aluminum membrane, (e) is biomass cellulose@alumina membrane, and (f) is biomass cellulose@aluminum-based membrane;
[0029] Figure 3 Scanning electron microscope images of biomass cellulose@metal hydroxide nanosheets, (g), (h) and (i) are all biomass cellulose@zinc aluminum hydroxide nanosheets;
[0030] Figure 4 Scanning electron microscope image of cellulose acetate;
[0031] Figure 5 Comparison chart of food preservation performance between polyethylene packaging materials and energy-saving packaging materials. Detailed Implementation
[0032] The present invention will be described in detail below with reference to embodiments, so that those skilled in the art can better understand the present invention, but the present invention is not limited to the following embodiments.
[0033] Example 1
[0034] A method for preparing a metal hydroxide-cellulose composite material includes the following steps:
[0035] a) Biomass fiber@high-purity aluminum film is prepared by magnetron sputtering technology. Specifically, in a nitrogen atmosphere, an aluminum target is loaded into a magnetron sputtering furnace, the target distance is adjusted to 10 mm, the sputtering power is 20 W, the sputtering time is 20 min, and high-purity aluminum is sputtered onto the surface of biomass fiber to obtain biomass fiber@high-purity aluminum film.
[0036] b) Weigh 1.4g of zinc nitrate and 0.57g of hexamethylenetetramine and dissolve them in 60mL of deionized water. Place the solution into a 100mL stainless steel reactor lined with polytetrafluoroethylene. Vertically place the biomass fiber@high-purity aluminum membrane into the Teflon container of the autoclave until it is completely submerged. React at 90℃ for 10h. After cooling, wash the solution multiple times with deionized water and ethanol, and dry it at room temperature for 24h to obtain biomass fiber@zinc aluminum hydroxide nanosheets.
[0037] c) Disperse 2g of sodium lauryl in 50mL of ethanol and stir at 50℃ for 3h to obtain a dispersion. Soak the above biomass fiber@zinc aluminum hydroxide nanosheets in the dispersion and react at 50℃ for 6h to obtain hydrophobic biomass cellulose@zinc aluminum hydroxide nanosheets.
[0038] d) Prepare an electrospinning solution by taking 4 mL of acetone and 16 mL of dichloromethane, dissolve 1.2 g of cellulose acetate in the electrospinning solution, stir at room temperature for 3 h to obtain an electrospinning solution of cellulose acetate, and deposit a layer of cellulose acetate on hydrophobic biomass cellulose@zinc aluminum hydroxide nanosheets using electrospinning technology to obtain the final product.
[0039] The surface morphology of biomass cellulose is presented in Figure 1 In (a), the biomass fibers are mechanically entangled to form a network structure, and the biomass fibers are randomly oriented; in addition, the biomass fibers exhibit a large aspect ratio, which is conducive to the formation of a strong and flat membrane.
[0040] The morphology of biomass cellulose@aluminum film is shown in Figure 2 In (d), the diameter of biomass fibers increases, and nano-aluminum is uniformly covered on the surface of cellulose fibers, providing an aluminum source for the subsequent acquisition of zinc aluminum hydroxide nanosheets.
[0041] The morphology of biomass cellulose@zinc aluminum hydroxide nanosheets is shown in Figure 3 (g) Nanosheets are randomly distributed on the surface of biomass fibers, forming a honeycomb-like rough surface, which is beneficial for enhancing their infrared emissivity. The morphology of cellulose acetate is shown in... Figure 4 Cellulose acetate interlacs to form a flat membrane. In addition, the porous structure on the surface of cellulose acetate is conducive to heat dissipation from sunlight and enhances its solar reflectivity.
[0042] A comparison of the food preservation performance of polyethylene packaging materials and energy-saving packaging materials is presented in [the following text is incomplete and likely refers to a separate topic:] Figure 5 (k) On the first day, there was no significant change between the two groups. However, on the third day, the stems and leaves of both groups began to turn yellow. The strawberries wrapped in polyethylene packaging had a slightly whitish surface, while those wrapped in energy-efficient packaging had a shinier surface. By day 12, the strawberries wrapped in polyethylene packaging were covered in mold, while the strawberries wrapped in energy-efficient packaging did not exhibit this phenomenon. Furthermore, spoilage, similar to an infectious disease, accelerates the deterioration of normal food, a deficiency mitigated by energy-efficient packaging.
[0043] Example 2
[0044] A method for preparing a metal hydroxide-cellulose composite material includes the following steps:
[0045] a) Prepare 200 mL of anhydrous ethanol and water mixed solution, add 7.50 g of aluminum nitrate to the above solution, adjust the pH of the solution to 4 with acetic acid, prepare an aluminum sol with a concentration of 0.1 mol / L, then soak the biomass fiber in it, let it stand for 1 h, dry it in an oven at 120 ℃ for 5 min, soak it in the sol again, repeat this process 5 times to obtain biomass fiber@alumina film;
[0046] b) Weigh 1.4g of zinc nitrate and 0.57g of hexamethylenetetramine and dissolve them in 60mL of deionized water. Place the solution into a 100mL stainless steel reactor lined with polytetrafluoroethylene. Vertically place the biomass fiber@alumina membrane into the Teflon container of the autoclave until it is completely submerged. React at 90℃ for 10h. After cooling, wash the membrane multiple times with deionized water and ethanol, and dry it at room temperature for 24h to obtain biomass fiber@zinc aluminum hydroxide nanosheets.
[0047] c) Disperse 2g of sodium lauryl in 50mL of ethanol and stir at 50℃ for 3h to obtain a dispersion. Soak the above biomass fiber@zinc aluminum hydroxide nanosheets in the dispersion and react at 50℃ for 6h to obtain hydrophobic biomass cellulose@zinc aluminum hydroxide nanosheets.
[0048] d) Prepare an electrospinning solution by taking 4 mL of acetone and 16 mL of dichloromethane, dissolve 1.2 g of cellulose acetate in the electrospinning solution, and stir at room temperature for 3 h to obtain an electrospinning solution of cellulose acetate; deposit a layer of cellulose acetate on hydrophobic biomass cellulose@zinc aluminum hydroxide nanosheets using electrospinning technology to obtain the final product.
[0049] The surface morphology of biomass cellulose is presented in Figure 1 In (b), the biomass fibers are mechanically entangled to form a network structure, and the biomass fibers are randomly oriented; in addition, the biomass fibers exhibit a large aspect ratio, which is conducive to the formation of a strong and flat membrane.
[0050] The morphology of biomass cellulose@aluminum film is shown in Figure 2 In (e), the diameter of biomass fibers increases, and nano-aluminum is uniformly covered on the surface of cellulose fibers, providing an aluminum source for the subsequent acquisition of zinc aluminum hydroxide nanosheets.
[0051] The morphology of biomass cellulose@zinc aluminum hydroxide nanosheets is shown in Figure 3 (h) Nanosheets are randomly distributed on the surface of biomass fibers, forming a honeycomb-like rough surface, which is beneficial for enhancing their infrared emissivity. The morphology of cellulose acetate is shown in... Figure 4 Cellulose acetate interlacs to form a flat membrane. In addition, the porous structure on the surface of cellulose acetate is conducive to heat dissipation from sunlight and enhances its solar reflectivity.
[0052] A comparison of the food preservation performance of polyethylene packaging materials and energy-saving packaging materials is presented in [the following text is incomplete and likely refers to a separate topic:] Figure 5 (l) On the first day, there was no significant change between the two groups. It wasn't until the 7th day that the tomatoes wrapped in polyethylene packaging showed damage, while the tomatoes wrapped in energy-saving packaging material remained shiny. By the 9th day, the difference in freshness became more obvious, demonstrating the practical application potential of energy-saving packaging materials.
[0053] Example 3
[0054] A method for preparing a metal hydroxide-cellulose composite material includes the following steps:
[0055] a) Biomass cellulose@aluminum-based packaging was prepared into biomass cellulose@zinc-aluminum hydroxide nanosheets using an in-situ growth technique. Specifically, 1.4 g of zinc nitrate and 0.57 g of hexamethylenetetramine were weighed and dissolved in 60 mL of deionized water, which was then placed in a 100 mL stainless steel reactor lined with polytetrafluoroethylene. The biomass cellulose@aluminum-based packaging was vertically placed into a Teflon container of an autoclave until completely submerged. The reaction was carried out at 90 °C for 10 h. After cooling, the nanosheets were washed multiple times with deionized water and ethanol, and then dried at room temperature for 24 h to obtain the biomass cellulose@zinc-aluminum hydroxide nanosheets.
[0056] b) Disperse 2g of sodium lauryl in 50mL of ethanol and stir at 50℃ for 3h to obtain a dispersion; immerse the above biomass fiber@zinc aluminum hydroxide nanosheets in it and react at 50℃ for 6h to obtain hydrophobic biomass cellulose@zinc aluminum hydroxide nanosheets.
[0057] c) Prepare an electrospinning solution by taking 4 mL of acetone and 16 mL of dichloromethane, dissolve 1.2 g of cellulose acetate in the spinning solution, stir at room temperature for 3 h to obtain an electrospinning solution of cellulose acetate, and deposit a layer of cellulose acetate on hydrophobic biomass cellulose@zinc aluminum hydroxide nanosheets using electrospinning technology to obtain the final product.
[0058] The surface morphology of biomass cellulose is presented in Figure 1 In (c), the biomass fibers are mechanically entangled to form a network structure, and the biomass fibers are randomly oriented; in addition, the biomass fibers exhibit a large aspect ratio, which is conducive to the formation of a strong and flat membrane.
[0059] The morphology of biomass cellulose@aluminum film is shown in Figure 2 In (f), the diameter of biomass fibers increases, and nano-aluminum is uniformly covered on the surface of cellulose fibers, providing an aluminum source for the subsequent acquisition of zinc aluminum hydroxide nanosheets.
[0060] The morphology of biomass cellulose@zinc aluminum hydroxide nanosheets is shown in Figure 3 (i) Nanosheets are randomly distributed on the surface of biomass fibers, forming a honeycomb-like rough surface, which is beneficial for enhancing their infrared emissivity. The morphology of cellulose acetate is shown in... Figure 4 Cellulose acetate interlacs to form a flat membrane. In addition, the porous structure on the surface of cellulose acetate is conducive to heat dissipation from sunlight and enhances its solar reflectivity.
[0061] A comparison of the food preservation performance of polyethylene packaging materials and energy-saving packaging materials is presented in [the following text is incomplete and likely refers to a separate topic:] Figure 5(m) On the first day, there was no significant change between the two groups. However, by the third day, the grapes wrapped in polyethylene packaging showed signs of damage, while those wrapped in energy-efficient packaging remained glossy. By the ninth day, the difference in freshness became more pronounced, demonstrating the practical application potential of energy-efficient packaging materials.
[0062] Example 4
[0063] A method for preparing a metal hydroxide-cellulose composite material includes the following steps:
[0064] a) Biomass fiber@high-purity aluminum film is prepared by magnetron sputtering technology. Specifically, under a nitrogen atmosphere, an aluminum target is loaded into a magnetron sputtering furnace, the target distance is adjusted to 10 mm, the sputtering power is 20 W, and the sputtering time is 20 min, and high-purity aluminum is sputtered onto the surface of biomass fiber to obtain biomass fiber@high-purity aluminum film.
[0065] b) Weigh 1.4g of zinc acetate and 0.57g of hexamethylenetetramine and dissolve them in 60mL of deionized water. Place the solution into a 100mL stainless steel reactor lined with polytetrafluoroethylene. Vertically place the biomass fiber@high-purity aluminum membrane into the Teflon container of the autoclave until it is completely submerged. React at 90℃ for 10h. After cooling, wash the solution multiple times with deionized water and ethanol, and dry it at room temperature for 24h to obtain biomass fiber@zinc aluminum hydroxide nanosheets.
[0066] c) Disperse 2g of sodium lauryl in 50mL of ethanol and stir at 50℃ for 3h to obtain a dispersion; immerse the above biomass fiber@zinc aluminum hydroxide nanosheets in it and react at 50℃ for 6h to obtain hydrophobic biomass cellulose@zinc aluminum hydroxide nanosheets.
[0067] d) Prepare an electrospinning solution by taking 4 mL of acetone and 16 mL of dichloromethane, dissolve 1.2 g of cellulose acetate in the electrospinning solution, and stir at room temperature for 3 h to obtain an electrospinning solution of cellulose acetate; deposit a layer of cellulose acetate on hydrophobic biomass cellulose@zinc aluminum hydroxide nanosheets using electrospinning technology to obtain the final product.
[0068] Example 5
[0069] A method for preparing a metal hydroxide-cellulose composite material includes the following steps:
[0070] a) Prepare 200 mL of anhydrous ethanol and water mixed solution, add 7.50 g of aluminum nitrate to the above solution, adjust the pH of the solution to 4 with acetic acid, prepare an aluminum sol with a concentration of 0.1 mol / L, immerse the biomass fiber in the sol, let it stand for 1 h, dry it in an oven at 120 ℃ for 5 min, and immerse it in the sol again. Repeat this process 5 times to obtain a biomass fiber@alumina film;
[0071] b) Weigh 1.4g of zinc oxide and 0.57g of hexamethylenetetramine and dissolve them in 60mL of deionized water. Place the solution into a 100mL stainless steel reactor lined with polytetrafluoroethylene. Vertically place the biomass fiber@alumina membrane into the Teflon container of the autoclave until it is completely submerged. React at 90℃ for 10h. After cooling, wash the membrane multiple times with deionized water and ethanol, and dry it at room temperature for 24h to obtain biomass fiber@zinc aluminum hydroxide nanosheets.
[0072] c) Disperse 2g of sodium lauryl in 50mL of ethanol and stir at 50℃ for 3h to obtain a dispersion. Soak the above biomass fiber@zinc aluminum hydroxide nanosheets in the dispersion and react at 5℃ for 6h to obtain hydrophobic biomass cellulose@zinc aluminum hydroxide nanosheets.
[0073] d) Prepare an electrospinning solution by taking 4 mL of acetone and 16 mL of dichloromethane, dissolve 1.2 g of cellulose acetate in the electrospinning solution, and stir at room temperature for 3 h to obtain an electrospinning solution of cellulose acetate; deposit a layer of cellulose acetate on hydrophobic biomass cellulose@zinc aluminum hydroxide nanosheets using electrospinning technology to obtain the final product.
[0074] Example 6
[0075] A method for preparing a metal hydroxide-cellulose composite material includes the following steps:
[0076] a) Biomass cellulose@aluminum-based packaging was prepared into biomass cellulose@zinc-aluminum hydroxide nanosheets using in-situ growth technology. Specifically, 1.4 g of zinc acetate and 0.57 g of hexamethylenetetramine were weighed and dissolved in 60 mL of deionized water, which was then placed in a 100 mL stainless steel reactor lined with polytetrafluoroethylene. The biomass cellulose@aluminum-based packaging was vertically placed into a Teflon container of a high-pressure reactor until it was completely submerged, and reacted at 90 °C for 10 h. After cooling, the nanosheets were washed multiple times with deionized water and ethanol, and then dried at room temperature for 24 h to obtain the biomass cellulose@zinc-aluminum hydroxide nanosheets.
[0077] b) Disperse 2g of sodium lauryl in 50mL of ethanol and stir at 50℃ for 3h to obtain a dispersion. Soak the above biomass fiber@zinc aluminum hydroxide nanosheets in the dispersion and react at 50℃ for 6h to obtain hydrophobic biomass cellulose@zinc aluminum hydroxide nanosheets.
[0078] c) Prepare an electrospinning solution by taking 4 mL of acetone and 16 mL of dichloromethane, dissolve 1.2 g of cellulose acetate in the spinning solution, and stir at room temperature for 3 h to obtain an electrospinning solution of cellulose acetate; deposit a layer of cellulose acetate on hydrophobic biomass cellulose@zinc aluminum hydroxide nanosheets using electrospinning technology to obtain the final product.
[0079] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made using the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.
Claims
1. A method for preparing a metal hydroxide-cellulose composite material, characterized in that, Includes the following steps: a) Prepare a 0.01-0.03 mol / L zinc salt solution, add hexamethylenetetramine to zinc salt at a molar ratio of 1:1 to 1:3, and stir until homogeneous to obtain the precursor reaction solution; b) Pour the precursor reaction solution into a stainless steel reactor lined with polytetrafluoroethylene. Immerse the biomass fiber with aluminum film coating at a ratio of 50-100 g / L to the precursor reaction solution. Perform a hydrothermal reaction at 60-120°C for 5-10 hours. After cooling and filtration, wash with distilled water 3-6 times and dry at 80-120°C for 12-24 hours to obtain biomass fiber with metal hydroxide nanosheets dispersed on the surface. c) Prepare a sodium lauryl solution with a concentration of 40-80 g / L. Based on a material ratio of 60-120 g / L between the biomass fiber with metal hydroxide nanosheets dispersed on the surface and the sodium lauryl solution, immerse the biomass fiber with metal hydroxide nanosheets dispersed on the surface into the solution and react at 50°C for 4-8 hours to obtain hydrophobic biomass fiber with metal hydroxide nanosheets dispersed on the surface. d) Prepare an electrospinning solution with a molar ratio of acetone to dichloromethane of 1:2 to 1:5, dissolve cellulose acetate in the solution to obtain an electrospinning solution with a concentration of 60 to 100 g / L, and electrospin the solution onto the surface of hydrophobic biomass fibers with metal hydroxide nanosheets dispersed on the surface to deposit cellulose acetate, thereby obtaining a metal hydroxide-cellulose composite material.
2. The method for preparing the metal hydroxide-cellulose composite material according to claim 1, characterized in that: In step a), the zinc salt is one or a combination of zinc nitrate, zinc acetate and zinc chloride.
3. The method for preparing the metal hydroxide-cellulose composite material according to claim 1, characterized in that: In step a), the molar ratio of hexamethylenetetramine to zinc salt is 1:
2.
4. The method for preparing the metal hydroxide-cellulose composite material according to claim 1, characterized in that: In step b), the biomass fiber with an aluminum film coating is a biomass fiber with a high-purity aluminum element or aluminum oxide coated on its surface.
5. The method for preparing the metal hydroxide-cellulose composite material according to claim 4, characterized in that: In step b), the biomass fiber with an aluminum film coating is prepared by magnetron sputtering when the surface of the biomass fiber is coated with high-purity aluminum.
6. The method for preparing the metal hydroxide-cellulose composite material according to claim 4, characterized in that: In step b), the biomass fiber with an aluminum film coating is prepared by sol-gel method when the surface of the biomass fiber is coated with aluminum oxide.
7. The metal hydroxide-cellulose composite material prepared according to any one of claims 1-6, characterized in that: The composite material is assembled from composite fibers and metal hydroxide nanosheets, wherein the composite fibers are composed of biomass fibers and cellulose acetate, and the metal hydroxide nanosheets are dispersed on the surface of the biomass fibers.
8. The metal hydroxide-cellulose composite material according to claim 7, characterized in that: The biomass fiber has a diameter of 10–40 μm; the acetate fiber has a diameter of 20–60 μm.
9. The metal hydroxide-cellulose composite material according to claim 7, characterized in that: The metal hydroxide-cellulose composite material consists of a hydrophilic acetate fiber layer and a biomass fiber layer with hydrophobic metal hydroxide nanosheets dispersed on the surface, and has asymmetric infrared radiation properties and asymmetric wetting properties.
10. An application of the metal hydroxide-cellulose composite material as described in any one of claims 7-9, characterized in that: It can be applied to energy-saving packaging materials.