Preparation method of plant ash filled cellulose-based composite material and aerogel

Abstract

According to the preparation method of the plant ash filled cellulose-based composite material and the aerogel, cellulose is modified by quaternary ammonium salt, plant ash is added, the roughness of the fiber surface in the aerogel is increased, the material structure is more compact, and the crystallinity and the surface charge density are improved through quaternary ammonium salt modification; calcium ions, potassium ions and other ions in the plant ash are complexed with the cellulose to enhance interface polarization, the dielectric property of the material is effectively improved, the triboelectricity output is enhanced, meanwhile, multi-scale fibers of the quaternary ammonium salt modified cellulose and the microfibrillated cellulose are entangled to serve as a framework, the mechanical stability of the composite material is enhanced, and the mechanical property of the composite material is improved. The composite material has the advantages of high humidity, good durability, environmental protection and sustainability, the preparation method does not need special equipment, the drying time is greatly shortened, the energy consumption is low, the operation is simple, the large-scale production is easy, and the prepared aerogel also has the characteristics of light weight, low apparent density, high plasticity, good flexibility and the like.

Description

Technical Field

[0001] This invention belongs to the field of cellulose composite material technology, specifically relating to a method for preparing a cellulose-based composite material filled with plant ash and an aerogel. Background Technology

[0002] The rapid development of the Internet of Things (IoT) has driven the demand for intelligent sensing technologies in fields such as smart homes and smart agriculture. Non-contact sensing has become a hot topic in the industry due to its advantages such as real-time operation, wide coverage, and low invasiveness. However, most mainstream sensors currently rely on external power sources, and large-scale deployment faces severe energy challenges.

[0003] Triboelectric nanogenerators, based on triboelectric charging and electrostatic induction effects, can simultaneously achieve energy harvesting and sensing functions, providing a new approach to solving energy problems. Among them, non-contact triboelectric nanogenerators also expand the detection dimensions.

[0004] However, traditional triboelectric materials (such as polyamide and polyethylene terephthalate) are non-renewable and difficult to degrade, and their large-scale application can easily lead to pollution and health risks. Furthermore, triboelectric nanogenerators lack environmental stability; in high-humidity environments, water molecules can transfer, neutralize, and dissipate the charge at the sensing interface, resulting in decreased sensitivity and reduced energy harvesting efficiency. In addition, the signal output intensity of non-contact sensing is several to tens of times weaker than that of contact sensing, and the charge retention time is very short.

[0005] Cellulose is an ideal candidate material due to its advantages of being renewable, biodegradable, and low-cost. Its molecular structure endows it with certain triboelectric potential, but natural cellulose has a low charge density and high hydrophilicity, which leads to rapid charge dissipation and poor structural stability under high humidity. Existing optimization schemes (such as composite modification and hydrophobic integration) have improved performance to some extent, but still have problems such as limited biocompatibility, insufficient long-term stability, and high cost.

[0006] Therefore, in order to solve the above problems, the present invention provides a method for preparing a cellulose-based composite material filled with plant ash and an aerogel. Summary of the Invention

[0007] This invention aims to address the comprehensive problems of existing triboelectric nanogenerators, such as insufficient humidity adaptability, insufficient triboelectric output of cellulose-based aerogels, high cost, and non-renewable materials. It provides a method for preparing a cellulose-based composite material filled with wood ash, comprising the following steps: S10: Prepare an aqueous solution of (3-chloro-2-hydroxypropyl)trimethylammonium chloride, add a strong base, and stir for the first time to form a quaternary ammonium salt solution; S20: Take softwood pulp, homogenize it to form cellulose fibers, add it to the quaternary ammonium salt solution, stir and heat it for a second time, and then wash it with water to form quaternary ammonium salt modified cellulose. S30: Take microfibrillated cellulose, wood ash and deionized water, mix them with the quaternary ammonium salt modified cellulose, and stir for a third time to obtain the composite material.

[0008] Furthermore, the microfibrillated cellulose has a fiber width of 50 nm to 200 nm and a fiber length of 20 μm to 500 μm.

[0009] Furthermore, the volume of the aqueous solution is 80 mL to 140 mL, and the mass of the (3-chloro-2-hydroxypropyl)trimethylammonium chloride is 1.4 g to 6.0 g.

[0010] Furthermore, the mass ratio of the strong base to the cellulose fiber in the quaternary ammonium salt modified cellulose is 1.0g to 1.2g: 1.8g to 3.0g.

[0011] Furthermore, the strong base is sodium hydroxide or potassium hydroxide.

[0012] Furthermore, when the volume of the deionized water used is 200 mL to 400 mL, the mass of the microfibrillated cellulose used is 0.6 g to 1.8 g, and the mass of the wood ash used is 0.36 g to 1.08 g.

[0013] Furthermore, the fallen leaves are washed, dried, burned into ash, and then ground to obtain the plant ash. The fallen leaves are one of the following: Euonymus japonicus, Ilex chinensis, Broussonetia papyrifera, Eriobotrya japonica, Livistona chinensis, Sycamorea foetida, or Camphor tree leaves.

[0014] Furthermore, the second stirring and heating is performed by stirring at a speed of 40 to 50 rpm at a temperature of 65 to 75°C for 50 to 70 minutes.

[0015] An aerogel of a cellulose-based composite material filled with plant ash is prepared by loading the composite material obtained by the above preparation method into a solvent-draining tool to remove the solvent, and then drying it to obtain the aerogel.

[0016] Furthermore, the drying process involves freezing at -18°C to -5°C for 2.0 to 4.5 hours, then drying at 55°C to 65°C for 20 to 35 minutes, followed by extrusion, and finally drying at 55°C to 65°C for 6 to 8 hours.

[0017] Compared with the prior art, the present invention has the following advantages: By using quaternary ammonium salts containing epoxy groups and adding wood ash, the surface roughness of the fibers in the aerogel was increased, making the material structure more compact. The introduction of microfibrillated cellulose effectively enhanced multi-scale cross-linking. Quaternary ammonium salt modification increased the crystallinity of the aerogel. The calcium and magnesium ions rich in wood ash could reconstruct the multi-cross-linked structure of the aerogel system. The combined effect of multiple factors enhanced the mechanical properties of the aerogel, with improvements in tensile strength, elastic modulus, compressive strength, and compressive modulus. At the same time, after the quaternary ammonium salts combined with the cellulose backbone, the polarization ability and mobility of the molecules were improved, as well as the dielectric properties and surface charge density. The calcium and potassium ions in wood ash complexed with cellulose, enhancing ionic polarization. The presence of calcium carbonate and magnesium carbonate crystals further enhanced interfacial polarization, thereby effectively improving the triboelectric output of the aerogel.

[0018] Furthermore, this material exhibits excellent performance in high humidity environments. When the relative humidity is between 30% and 80%, the voltage and current increase with the increase of humidity, demonstrating high humidity sensitivity and reversible humidity response. After 14,000 cycles at a relative humidity of 83%RH, the output voltage remains stable, demonstrating good high humidity durability and maintaining good self-powered process efficiency in high humidity environments.

[0019] This invention uses quaternary ammonium salt modified cellulose and microfibrillated cellulose fibers as base materials, combined with wood ash from burning fallen leaves. It is both environmentally friendly and sustainable. The preparation method does not involve any special or difficult preparation process, so it does not require special equipment and is easy to scale up. The preparation process greatly shortens the drying time, has low energy consumption, and is simple to operate. The resulting aerogel also has the characteristics of being lightweight, having low apparent density, high plasticity, and good flexibility. At the same time, it has good applicability to wood ash made from different varieties of fallen leaves, and the solution has strong scalability and universal applicability.

[0020] This invention represents a revolutionary approach to triboelectric composite materials and aerogels, employing a minimalist raw material composition and a simplified preparation process to achieve superior performance. In contrast to existing cellulose-based triboelectric composite materials, which often require dozens of raw materials with varying environmental standards and complex preparation processes involving numerous steps, this invention utilizes readily available and environmentally friendly raw materials. The main raw materials (cellulose fiber and wood ash) are widely available and extremely low-cost. The entire preparation process comprises no more than ten steps (or even five). Therefore, from raw material usage to the preparation process, this invention offers convenience, low cost, and ease of operation. The resulting material exhibits excellent performance, is suitable for large-scale production, and demonstrates strong applicability. Attached Figure Description

[0021] Figure 1This is a moldable image of the aerogel prepared in Example 1 of the present invention. Figure 1 Figure I shows aerogels of various shapes, Figure II shows aerogels in different bending states, and Figure III shows aerogels in different twisting states. Figure 2 The images show surface SEM images of the aerogels prepared in Comparative Examples 1 to 4 of this invention, and cross-sectional SEM and EDS images of the aerogels prepared in Example 1. Figure 2 Figures (a) to (h) are SEM images of the aerogels prepared in Comparative Examples 1 to 4 on their surfaces. Figure 2 Figures (i) and (j) in the figure are SEM images of the cross-section of the aerogel prepared in Example 1; Figure 2 Figures (k) and (l) in the figure are EDS images of the cross-section of the aerogel prepared in Example 1; Figure 3 For CF, C2M1, C2M1S 10 A 10 C2M1, A 12 C2M1S 10 A 40 C2M1S 20 EDS energy dispersive spectroscopy analysis of the samples (including) Figure 3 Figure (a) in the middle Figure 3 (f) in the middle); Figure 4 Infrared spectra of the aerogels prepared in Example 1 and Comparative Examples 1 to 4 of this invention; Figure 5 X-ray diffraction patterns of the aerogels prepared in Example 1 and Comparative Examples 1 to 4 of this invention; Figure 6 Tensile stress-strain diagrams, maximum tensile strength diagrams, and elastic modulus diagrams of the aerogels prepared in Example 1 and Comparative Examples 1 to 4 of the present invention. Figure 7 The compression stress-strain diagram and compression modulus diagram of the aerogels prepared in Example 1 and Comparative Examples 1 to 4 of this invention; Figure 8 This is a schematic diagram illustrating the working principle of the aerogels prepared in Example 1 and Comparative Examples 1 to 4 of the present invention assembled into a vertical contact-separation mode triboelectric nanogenerator. Figure 9 This is a short-circuit current signal diagram of the aerogel-based triboelectric nanogenerator prepared in Example 1 of the present invention under one cycle; Figure 10 The open-circuit voltage diagrams of the aerogel-based triboelectric nanogenerators prepared in Comparative Examples 1 to 4 of this invention under the conditions of an operating frequency of 5 Hz and an operating force of 10 N are shown. Figure 11 Open-circuit voltage diagrams of aerogel-based triboelectric nanogenerators with different amounts of plant ash prepared using the process of Example 1 of this invention; Figure 12 Open-circuit voltage diagrams of aerogel-based triboelectric nanogenerators prepared using different concentrations of (3-chloro-2-hydroxypropyl)trimethylammonium chloride solution through the process of Example 1 of this invention; Figure 13 Open-circuit voltage diagrams of aerogel-based triboelectric nanogenerators with different ratios of cellulose fibers to microfibrillated cellulose prepared using the process of Example 1 of this invention. Figure 14 Figure (a) shows the open-circuit voltage of triboelectric nanogenerators with different positive and negative friction layer spacings assembled from the aerogel prepared in Example 1 of this invention and commercial polytetrafluoroethylene film. Figure 14 Figure (b) shows the open-circuit voltage of aerogel-based triboelectric nanogenerators of different thicknesses prepared in Example 1 of this invention; Figure 15 The pressure sensing diagram and fatigue resistance result diagram of the aerogel-based triboelectric nanogenerator prepared in Example 1 of the present invention are shown. Figure 15 Figure (a) shows the open-circuit voltage under different applied forces (1N to 20N). Figure 15 Figure (b) shows the short-circuit current under different applied forces (1N to 20N). Figure 15 Figure (c) shows the charge transfer under different applied forces (1N to 20N). Figure 15 Figure (d) shows the linear relationship between open-circuit voltage and applied force. Figure 15 Figure (e) in the figure shows the open-circuit voltage of the aerogel-based triboelectric nanogenerator prepared in Example 1 during 13,000 cycles; Figure 16 The diagram shows the open-circuit voltage, short-circuit current, and output power density of the aerogel-based triboelectric nanogenerator prepared in Example 1 of this invention under an external variable resistor. Figure 17 The graph shows the triboelectric output performance of the aerogel-based triboelectric nanogenerator prepared in Example 1 of this invention under different relative humidity environments. Figure 17 Figure (a) shows the open-circuit voltage of the aerogel-based triboelectric nanogenerator prepared in Example 1 under different humidity conditions. Figure 17 Figure (b) shows the short-circuit current of the aerogel-based triboelectric nanogenerator prepared in Example 1 under different humidity conditions; Figure 18 This is a schematic diagram showing how the aerogel-based triboelectric nanogenerator prepared in Example 1 of the present invention enhances electrical output in a humid environment by forming hydrogen bonds at the interface to bind water and ion channels. Figure 19 This is a wet sensing sensitivity diagram of the aerogel-based triboelectric nanogenerator prepared in Example 1 of the present invention; Figure 19 Figure (a) in the figure is a fitting curve of the open circuit voltage and short circuit current of the aerogel-based triboelectric nanogenerator prepared in Example 1 as a function of humidity in the range of relative humidity from 30% to 80%. Figure 19 Figure (b) shows the open-circuit voltage response of the aerogel-based triboelectric nanogenerator prepared in Example 1 during humidification or dehumidification. Figure 20 The open-circuit voltage diagram of the aerogel-based triboelectric nanogenerator prepared in Example 1 of the present invention after 14,000 contact-separation cycles at 83% relative humidity. Figure 21 The real-time open-circuit voltage of the aerogel-based triboelectric nanogenerator prepared in Example 1 of this invention is obtained by intermittently exhaling air into the triboelectric layer during the operation driven by a commercial exciter. Figure 22 This is a product application diagram of the aerogel-based triboelectric nanogenerator prepared in Example 1 of the present invention. Figure 22 Figure (a) shows a schematic diagram of powering 632 LEDs. Figure 22 Figure (b) shows the charging curves of commercial capacitors ranging from 0.22 μF to 10 μF. Figure 22 Figure (c) in the diagram is a schematic diagram of the process of powering an electronic stopwatch that requires a 3V power supply; Figure 23 The diagram shows the output voltage of the aerogel-based triboelectric nanogenerator prepared in Example 1 of this invention as a sensor for detecting human motion. Figure 23 Figure (a) shows the output voltage as a contact sensor for detecting human movement. Figure 23 Figure (b) shows the output voltage as a non-contact sensor for detecting human motion; Figure 24 This diagram shows the application of the aerogel-based triboelectric nanogenerator prepared in Example 1 of this invention in a burglar alarm. Figure 24 Figure (a) in the figure is a schematic diagram of the aerogel-based triboelectric nanogenerator prepared in Example 1 as a burglar alarm. Figure 24 Figure (b) in the diagram is a schematic diagram of the operation of a simulated alarm. Figure 25 Open-circuit voltage diagram of an aerogel-based triboelectric nanogenerator prepared using the process of Example 1 of this invention from plant ash made from fallen leaves of different varieties. Figure 26 This is a diagram illustrating the degradation process of the aerogel prepared in Example 1 of the present invention; Figure 27This is a comparison chart of the electrical output performance of the aerogel-based triboelectric nanogenerator prepared by multiple recycling of the aerogel in Example 1 of this invention. Figure 27 Figure (a) in the figure is a comparison of open-circuit voltages. Figure 27 Figure (b) in the diagram is a comparison of short-circuit currents. Figure 27 Figure (c) in the figure is a comparison of charge transfer amounts. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] It should be noted that the technical terms used in this invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of this invention. Unless otherwise specified, all raw materials, reagents, instruments and equipment used in the following embodiments of this invention can be purchased from the market or prepared by existing methods.

[0024] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features; thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0025] The weights of the relevant components mentioned in the embodiments of this invention can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, as long as the content of the relevant components is scaled up or down proportionally according to the embodiments of this invention, it is within the scope disclosed in the embodiments of this invention. Specifically, the weights mentioned in the embodiments of this invention can be well-known mass units in the chemical industry, such as μg, mg, g, kg, nm, μm, cm, mm, wt%, mPa, L, mL, etc.

[0026] The following specific examples will provide further explanation.

[0027] The preparation method of the plant ash-filled cellulose-based composite material of this embodiment includes the following steps: S10: Prepare an aqueous solution of (3-chloro-2-hydroxypropyl)trimethylammonium chloride, add a strong base, and stir for the first time to form a quaternary ammonium salt solution; S20: Take softwood pulp, homogenize it to form cellulose fibers, add it to the quaternary ammonium salt solution, stir it a second time while heating, and then wash it with water to form quaternary ammonium salt modified cellulose. S30: Take microfibrillated cellulose, wood ash and deionized water, mix them with the quaternary ammonium salt modified cellulose, and stir for a third time to obtain the composite material.

[0028] It is worth noting that step S10 above is actually a cyclization reaction of a quaternary ammonium salt without epoxy groups under alkaline conditions to obtain a quaternary ammonium salt containing epoxy groups.

[0029] The preparation method of the plant ash-filled cellulose-based composite material in this embodiment is as follows: The composite material includes the following formulations: An aqueous solution of (3-chloro-2-hydroxypropyl)trimethylammonium chloride: 80 mL to 140 mL, preferably 120 mL, wherein the mass of (3-chloro-2-hydroxypropyl)trimethylammonium chloride is 1.4 g to 6.0 g; Sodium hydroxide or potassium hydroxide: 1.0g to 1.2g; Cellulose fiber: 1.8 to 3.0 g; Microfibrillated cellulose: 0.6 to 1.8 g, with a fiber width of 50 nm to 200 nm and a fiber length of 20 μm to 500 μm; Wood ash: 0.36 to 1.08 g; Deionized water: 200 mL to 400 mL, preferably 300 mL.

[0030] The preparation steps are as follows: Step S10: Add sodium hydroxide or potassium hydroxide to the aqueous solution of (3-chloro-2-hydroxypropyl)trimethylammonium chloride and stir for the first time to obtain a quaternary ammonium salt solution.

[0031] Step S20: Homogenize the softwood pulp to form cellulose fibers, add them to a quaternary ammonium salt solution, stir at a speed of 40 r / min to 50 r / min at a temperature of 65°C to 75°C for 50 min to 70 min, then wash with water to form quaternary ammonium salt modified cellulose.

[0032] Step S30: Take fallen leaves, wash, dry, burn them into ash, grind them to obtain wood ash, then take microfibrillated cellulose, deionized water, and mix them with quaternary ammonium salt modified cellulose, and stir for a third time to obtain the composite material.

[0033] This invention also provides an aerogel made using a cellulose-based composite material filled with plant ash. The prepared composite material is placed in a solvent draining tool with a screen at the bottom to drain the solvent. The solvent draining tool is a three-dimensional hollow mold with a geometric structure. At least one side of the mold is made of a screen, which can be selected from one of the following: mesh, PTFE mesh, nylon mesh, PVC mesh, PET mesh, PP mesh, steel mesh, or aluminum mesh. The mesh size of the screen is 80 to 120 mesh. Then, it is frozen at -18°C to -5°C for 2.0 to 4.5 hours, dried at 55°C to 65°C for 20 to 35 minutes, extruded, and finally dried at 55°C to 65°C for 6 to 8 hours to obtain an aerogel of the cellulose composite plant ash system.

[0034] This embodiment first involves removing hydrogen chloride from (3-chloro-2-hydroxypropyl)trimethylammonium chloride under a strongly alkaline environment to generate 2,3-epoxypropyltrimethylammonium chloride, forming a quaternary ammonium salt containing epoxy groups. This quaternary ammonium salt then reacts with the hydroxyl groups in homogenized cellulose fibers to attach the quaternary ammonium salt to the molecules of the cellulose fibers, forming a cationic cellulose ether, thus obtaining quaternary ammonium salt modified cellulose.

[0035] Next, quaternary ammonium salt modified cellulose and microfibrillated cellulose are mixed by high-speed stirring to form multi-scale fiber entanglement. Then, wood ash is added. The abundant magnesium, calcium and other metal ions in the wood ash can form chelate bonds with the active groups in the cellulose fibers. This forms a triple network structure composed of chemical crosslinking, ionic complexation and hydrogen bonding, making the material structure more stable.

[0036] Then, pour the mixed sample into a solvent draining tool to drain off excess solvent, and then put it in a refrigerator to freeze at a temperature of -18°C to -5°C. The low temperature causes the cellulose chains to aggregate more tightly laterally due to hydrogen bonding. When freezing, water molecules form ice crystals, which further compress the skeletal structure of the material, causing the fibers to form a layered structure.

[0037] After freezing, the sample was dried in an oven for 20 to 35 minutes. Then, the sample was placed between glass plates and quickly squeezed to remove most of the solvent. After drying, the sample was thoroughly dried to obtain the aerogel of the cellulose composite plant ash system.

[0038] Please see Figure 1 , Figure 1 This is a moldable image of the aerogel prepared in Example 1 of the present invention. Figure 1 Figure I shows aerogels of various shapes, Figure II shows aerogels in different bending states, and Figure III shows aerogels in different twisting states.

[0039] This preparation method does not involve any special or difficult preparation process, so it does not require special equipment and greatly shortens the drying time. This process is not only low in energy consumption and simple to operate, but also green and environmentally friendly and easy to scale up. Furthermore, the aerogel made using composite materials has excellent properties such as light weight and low apparent density, as well as high plasticity and good flexibility.

[0040] To further illustrate the effect of the dosage of each key component in this embodiment on the performance of the composite material, cellulose-based aerogels prepared in Example 1 and Comparative Examples 1 to 4 as shown in the table below are provided and tested.

[0041] Table 1 - Formulation Scheme Table for Implementation Methods:

[0042] It should be noted that the aerogel formed in Comparative Example 1 may be referred to as CF in the specific embodiments and accompanying drawings; the aerogel formed in Comparative Example 2 may be referred to as C2M1 in the specific embodiments and accompanying drawings; and the aerogel formed in Comparative Example 3 may be referred to as C2M1S in the specific embodiments and accompanying drawings. 10 The aerogel formed in Comparative Example 4 is referred to as A in the specific embodiments and accompanying drawings. 10 C2M1.

[0043] Wherein, A represents (3-chloro-2-hydroxypropyl)trimethylammonium chloride, C represents cellulose fiber, M represents microfibrillated cellulose, and S represents wood ash.

[0044] The aerogel prepared in Example 1 of this invention is A x C y M1S z In subsequent testing, the variables of different components in the formulation of Example 1 need to be analyzed, where "x" represents the concentration of the aqueous solution of (3-chloro-2-hydroxypropyl)trimethylammonium chloride (preferably: 12 g / L, 30 g / L, 35 g / L, 40 g / L, 45 g / L, 50 g / L, where 12 g / L is illustrated comparatively in the accompanying drawings of the specification; specifically, in the accompanying drawings...). Figure 3 , 6 (For comparison, 7 and 11), "y" represents the relative ratio of cellulose fiber to microfibrillated cellulose (preferably 1, 2, 3, 4 and 5), and "z" represents the percentage of wood ash relative to the total fiber (preferably 10wt%, 15wt%, 20wt%, 25wt% and 30wt%).

[0045] It should be noted that in the detailed embodiments and accompanying drawings, CF represents cellulose fiber aerogel, MCF represents microfibrillated cellulose, and PLSH represents wood ash.

[0046] Please see Figure 2 and Figure 3 , Figure 2 The images show surface SEM images of the aerogels prepared in Comparative Examples 1 to 4 of this invention, and cross-sectional SEM and EDS images of the aerogels prepared in Example 1. Figure 2 Figures (a) to (h) are SEM images of the aerogels prepared in Comparative Examples 1 to 4 on their surfaces. Figure 2 Figures (i) and (j) in the figure are SEM images of the cross-section of the aerogel prepared in Example 1; Figure 2 Figures (k) and (l) in the figure are EDS images of the cross-section of the aerogel prepared in Example 1; Figure 3 For CF, C2M1, C2M1S 10 A 10 C2M1, A 12 C2M1S 10 A 40 C2M1S 20 EDS energy dispersive spectroscopy analysis of the samples (including) Figure 3 Figure (a) in the middle Figure 3 (f) in the figure.

[0047] In Comparative Example 1, the fibers on the surface of the aerogel are coarse and flat, and the fibers are intertwined. In Comparative Example 2, the fibers are more tightly arranged, and large areas of coarse and fine fibers adhere together on the surface. In Comparative Example 4, the fiber surface of the aerogel is rougher, and a small number of pores appear on the surface. In Comparative Example 3, the fiber surface of the aerogel has more obvious damage and more pores.

[0048] from Figure 2 Figure (a) shows that the surface of the aerogel in Example 1 has interwoven coarse and fine fibers with obvious pores. Figure 2 Figure (j) clearly shows wood ash particles of varying sizes distributed on the fibers, combined with... Figure 2 As shown in Figure (d), the quaternary ammonium salt modification and the addition of wood ash significantly increased the surface roughness of the fibers in the aerogel. Figure 2 Figure (k) is an electron microscope image of a cross-section of Example 4. It clearly shows that the fibers are distributed in layers, exhibiting significant order. This structure makes the overall structure of the aerogel more compact. Finally, combined with… Figure 2 (l) diagram and Figure 3 The EDS results confirm that the addition of wood ash introduces Ca, Si, Mg, and K elements.

[0049] Table 2 - Corresponding Figure 3 EDS test data table:

[0050] Please see Figure 4 , Figure 4 The infrared spectra of the aerogels prepared in Example 1 and Comparative Examples 1 to 4 of this invention are shown.

[0051] like Figure 4 As shown, Comparative Example 1 is at 1030cm -1 897cm -1 and 1156cm -1 The characteristic peak of the cellulose macromolecular structure is present at 3200 cm⁻¹; Comparative Example 2, due to the presence of microfibrillated cellulose introducing a large number of hydroxyl groups, has a peak at 3200 cm⁻¹. -1 The absorption band near the sample widens; in Comparative Example 3, due to the introduction of carbonates from wood ash, the absorption bands at 1430 and 860 cm⁻¹ are [missing information]. -1 The absorption band near the peak is enhanced; in Comparative Example 4, the introduction of quaternary ammonium salt leads to changes in the number of hydrogen bonds, the number of alkyl groups, the introduction of quaternary ammonium salt groups, and the tensile strength of the COC pyranose ring, respectively, thus affecting the absorption band at 3300 cm⁻¹. -1 2900cm -1 1472cm -1 and 1030cm -1 The increased peak intensity nearby demonstrates the successful grafting of (3-chloro-2-hydroxypropyl)trimethylammonium chloride; and the stronger quaternary ammonium salt and carbonate peaks in Example 1 compared to Comparative Example 2, thus verifying the successful modification of cellulose fibers.

[0052] Please see Figure 5 , Figure 5 The X-ray diffraction patterns are of the aerogels prepared in Example 1 and Comparative Examples 1 to 4 of the present invention.

[0053] Please see Figure 5 The aerogels in Comparative Examples 1, 2, 3, 4 and Example 1 all showed typical diffraction peaks of cellulose I at 15.1°, 16.5°, 22.5° and 34.5° (corresponding to (1-10), (110), (200) and (004) crystal planes), indicating that the ammonium salt treatment and the introduction of plant ash did not change the cellulose crystal structure.

[0054] The significant difference lies in the presence of characteristic peaks of calcium carbonate and magnesium carbonate near 2θ=30° and 36° in Comparative Example 3 (confirming the successful introduction of wood ash), and a significant decrease in the intensity of the cellulose diffraction peak (especially at (200)). This is because the complexation of wood ash and cellulose reduces the crystallinity. The intensity of the cellulose diffraction peak in Comparative Example 4 is significantly enhanced because the molecule of (3-chloro-2-hydroxypropyl)trimethylammonium chloride is grafted onto the cellulose chain, increasing the crystallinity. In contrast, the crystallinity of cellulose molecules in Example 1 decreases under the competitive effect of quaternary ammonium salt modification and wood ash, proving that both are successfully introduced.

[0055] Please see Figure 6 , Figure 6The tensile stress-strain diagram, maximum tensile strength diagram, and elastic modulus diagram of the aerogels prepared in Example 1 and Comparative Examples 1 to 4 of this invention are shown (wherein: Figures a and b include A in Example 1). 12 C2M1S 10 A 12 C2M1S 20 A 12 C2M1S 30 And Comparative Examples 1 to 4, Figures c and d include A from Example 1. 30 C2M1S 20 A 40 C2M1S 20 A 50 C2M1S 20 A 40 C1M1S 20 A 40 C3M1S 20 ).

[0056] like Figure 6 As shown, the tensile strength and elastic modulus of the aerogel in Comparative Example 1 were 0.4 MPa and 10.8 MPa, respectively; while the tensile strengths of Comparative Examples 2, 3, and 4 were 5.9 MPa, 8.5 MPa, and 12.9 MPa, respectively, and the elastic moduli were 243.9 MPa, 356.1 MPa, and 611.8 MPa, respectively. This demonstrates that the addition of microfibrillated cellulose, (3-chloro-2-hydroxypropyl)trimethylammonium chloride, and wood ash can effectively improve the tensile strength and modulus of the aerogel.

[0057] It is worth noting that the tensile strength and modulus of Example 1 decreased with the increase of wood ash content. This is because microfibrillated cellulose enhances multi-scale cross-linking, and (3-chloro-2-hydroxypropyl)trimethylammonium chloride increases crystallinity, both of which contribute to tensile properties. Although the crystallinity of the aerogel decreases after adding wood ash, the introduced ions can reconstruct the multi-cross-linked network structure of the aerogel system. Therefore, the tensile properties of the aerogel are improved after adding a small amount of wood ash. However, if too much wood ash is added, it will accumulate on the fiber surface, thereby negatively affecting its tensile properties.

[0058] Furthermore, the changes in tensile strength and modulus from Comparative Examples 1 to 4 indicate that the concentration of (3-chloro-2-hydroxypropyl)trimethylammonium chloride and the ratio of cellulose fiber to microfibrillated fiber have no significant effect on the tensile properties of aerogel.

[0059] Please see Figure 7 , Figure 7 The compression stress-strain diagrams and compression modulus diagrams of the aerogels prepared in Example 1 and Comparative Examples 1 to 4 of this invention are shown (wherein: Figures a and b include A in Example 1). 12C2M1S 10 A 12 C2M1S 20 A 12 C2M1S 30 And Comparative Examples 1 to 4, Figures c and d include A from Example 1. 30 C2M1S 20 A 40 C2M1S 20 A 50 C2M1S 20 A 40 C1M1S 20 A 40 C3M1S 20 ).

[0060] like Figure 7 As shown in Figure (a), the addition of microfibrillated cellulose, (3-chloro-2-hydroxypropyl)trimethylammonium chloride, and wood ash can improve the compressive strength and compressive modulus of aerogels. In particular, the compressive strength of the aerogel in Comparative Example 2 at 30% strain is 3.4 MPa, which is a significant improvement compared to Comparative Example 1. Although the addition of (3-chloro-2-hydroxypropyl)trimethylammonium chloride and wood ash reduces the compressive strength of the aerogels in the examples, by adjusting the relative amounts of the two, a compressive strength similar to that of Comparative Example 2 can still be achieved. Figure 7 Figure (c) in the middle and Figure 7 (d) in the middle), while A 30 C2M1S 20 The aerogel prepared using the process of Example 1 (with an aqueous solution of (3-chloro-2-hydroxypropyl)trimethylammonium chloride at a concentration of 30 g / L, a relative ratio of cellulose fiber to microfibrillated cellulose of 2, and a relative percentage of wood ash to total fiber of 20 wt%) had the highest compressive strength of 3.5 MPa.

[0061] Please see Figure 8 , Figure 8 This is a schematic diagram illustrating the working principle of the aerogels prepared in Example 1 and Comparative Examples 1 to 4 of the present invention assembled into a vertical contact-separation mode triboelectric nanogenerator (wherein: Figure 8 Figure a in the diagram represents the structural principle of a triboelectric nanogenerator. Figure 8 Figure b in the figure shows the working principle diagram of the triboelectric device of the triboelectric nanogenerator.

[0062] like Figure 8As shown in Figure (a), the aerogel of this embodiment is used as the triboelectric positive electrode, the polytetrafluoroethylene film as the negative electrode, the copper sheet as the back electrode and connected to the external circuit, and the ethylene-vinyl acetate sponge as the separator to assemble a vertical contact-separation mode triboelectric nanogenerator. Its triboelectric performance is evaluated by measuring the electrical output. At the same time, the aerogel-based triboelectric nanogenerators of Comparative Example 1, Comparative Example 2 and Comparative Example 3 are assembled in the same way for comparison.

[0063] like Figure 8 Figure (b) shows the working principle diagram of the triboelectric nanogenerator, including processes (I) to (V), specifically: (I) In the initial state, the positive and negative electrodes are separated, no charge is generated, and the potential at both ends is zero; (II) Under the action of external force, the aerogel comes into contact with the polytetrafluoroethylene film. Due to the triboelectric charge, surface charge transfer occurs in the contact area. Positive charge is induced on the surface and inside of the aerogel, while negative charge is induced on the surface of the polytetrafluoroethylene film. Since the triboelectric charge exists only on the contact surface, the charges with opposite signs almost coincide on the same plane, and there is almost no potential difference between the two electrodes; (III) When the applied external force is removed, the positive and negative charges at both ends form a potential difference, and charge transfer occurs between the electrodes in the external circuit; (IV) As the charge transfer occurs, the potentials at both ends gradually tend to be equal, and finally electrostatic equilibrium is reached; (V) When force is applied to the triboelectric nanogenerator again, the aerogel and the polytetrafluoroethylene film gradually approach each other, and a reverse potential difference is generated between them, thus forming a negative signal.

[0064] The repeated contact and separation of triboelectric materials cause the electrodes at both ends to continuously accumulate charge, forming a stable electrical output signal.

[0065] Please see Figure 9 , Figure 9 This is a short-circuit current signal diagram of the aerogel-based triboelectric nanogenerator prepared in Example 1 of the present invention under one cycle.

[0066] like Figure 9 As shown, the current signal characteristics of the triboelectric nanogenerator based on Example 1 verified the above mechanism during the repeated vertical contact and separation process driven by external force.

[0067] Please see Figure 10 , Figure 10 The open-circuit voltage diagrams are shown for the aerogel-based triboelectric nanogenerators prepared in Comparative Examples 1 to 4 of this invention under the conditions of an operating frequency of 5 Hz and an operating force of 10 N.

[0068] like Figure 10 As shown, under the conditions of an operating frequency of 5 Hz and an operating force of 10 N, the aerogel-based triboelectric nanogenerators prepared in Comparative Examples 1, 2, 3, and 4 (corresponding to CF, C2M1, and C2M1S in the figure, respectively) 10 A 10The open-circuit voltages of C2M1 were 35.2V, 74.4V, 111.5V, and 116.4V, respectively. The open-circuit voltages of Comparative Examples 2, 3, and 4 were 211.3%, 316.7%, and 330.6% higher than those of the aerogel-based triboelectric nanogenerator in Comparative Example 1, respectively. Therefore, it can be concluded that microfibrillated cellulose, (3-chloro-2-hydroxypropyl)trimethylammonium chloride, and wood ash all have the effect of improving the open-circuit voltage.

[0069] Please see Figure 11 , Figure 11 Open-circuit voltage diagrams of aerogel-based triboelectric nanogenerators with different amounts of plant ash prepared using the process of Example 1 of this invention (wherein: the aerogel of Example 1 includes A) 12 C2M1S z "z" represents the percentage of wood ash relative to the total fiber content, which are 10wt%, 15wt%, 20wt%, 25wt%, and 30wt%, respectively.

[0070] like Figure 11 As shown, the open-circuit voltage of the triboelectric nanogenerator first increases and then decreases with the amount of wood ash used. This indicates that the calcium and potassium ions in the wood ash complex with cellulose, increasing ionic polarization. The presence of crystals such as calcium carbonate and magnesium carbonate increases the boundary between crystalline and amorphous regions in the system, enhancing interfacial polarization. The open-circuit voltage of A12C2M1S20 (aerogel prepared using the process of Example 1: the concentration of (3-chloro-2-hydroxypropyl)trimethylammonium chloride aqueous solution is 12 g / L, the relative ratio of cellulose fiber to microfibrillated cellulose is 2, and the proportion of wood ash relative to the total fiber is 20 wt%) is the largest, at 170.9 V. If there is excessive wood ash, it is easy to agglomerate and disperse unevenly, resulting in reduced output.

[0071] Please see Figure 12 The open-circuit voltage diagrams of aerogel-based triboelectric nanogenerators prepared using different concentrations of (3-chloro-2-hydroxypropyl)trimethylammonium chloride solution according to the process of Example 1 of this invention are shown (wherein: the aerogel of Example 1 includes A...). x C2M1S 20 "x" represents the concentration of the aqueous solution of (3-chloro-2-hydroxypropyl)trimethylammonium chloride, which are 30 g / L, 35 g / L, 40 g / L, 45 g / L, and 50 g / L, respectively.

[0072] like Figure 12 As shown, the electrical output of the triboelectric nanogenerator increases with the increase of the concentration of (3-chloro-2-hydroxypropyl)trimethylammonium chloride solution. When the concentration of (3-chloro-2-hydroxypropyl)trimethylammonium chloride reaches 40 g / L, the open-circuit voltage of the triboelectric nanogenerator hardly changes and tends to stabilize.

[0073] The open-circuit voltage of the aerogel-based triboelectric nanogenerator in Example 1 reaches 307.3V. This is because the nitrogen atoms in (3-chloro-2-hydroxypropyl)trimethylammonium chloride, after combining with the cellulose backbone, become partially positive charge centers, altering the electron density of adjacent carbon atoms and enhancing the polarization ability of the molecule. Furthermore, the absence of hydrogen bonds between nitrogen and oxygen makes the molecule more mobile. The movement of positive and negative charge centers changes the dipole moment, thereby increasing the dielectric properties of the modified cellulose. Simultaneously, the increased crystallinity of the aerogel increases the amount of polarization charge during the contact charging process, and the introduced cationic groups further increase the charge density on the material surface.

[0074] However, since the reaction between (3-chloro-2-hydroxypropyl)trimethylammonium chloride and cellulose is limited, the open-circuit voltage of the triboelectric nanogenerator hardly increases when its dosage is increased to a certain extent.

[0075] Please see Figure 13 , Figure 13 Open-circuit voltage diagrams of aerogel-based triboelectric nanogenerators with different ratios of cellulose fibers to microfibrillated cellulose prepared using the process of Example 1 of this invention.

[0076] like Figure 13 The figure shows the effect of the ratio of ammonium salt modified cellulose fibers to microfibrillated cellulose on the open circuit voltage, indicating that the aerogel ratio in Example 1 is optimal.

[0077] Please see Figure 14 , Figure 14 Figure (a) shows the open-circuit voltage of triboelectric nanogenerators with different positive and negative friction layer spacings assembled from the aerogel prepared in Example 1 of this invention and commercial polytetrafluoroethylene film. Figure 14 Figure (b) shows the open-circuit voltage of aerogel-based triboelectric nanogenerators of different thicknesses prepared in Example 1 of the present invention.

[0078] like Figure 14 As shown, by analyzing the effects of the interlayer spacing of the positive and negative friction surfaces and the aerogel thickness in Example 1 on the output of the triboelectric nanogenerator, the interlayer spacing of the triboelectric nanogenerator device with the optimal open-circuit voltage was determined to be 15 mm and the aerogel thickness to be 6 mm.

[0079] Please see Figure 15 , Figure 15 The pressure sensing diagram and fatigue resistance result diagram of the aerogel-based triboelectric nanogenerator prepared in Example 1 of the present invention are shown. Figure 15 Figure (a) shows the open-circuit voltage under different applied forces (1N to 20N). Figure 15 Figure (b) shows the short-circuit current under different applied forces (1N to 20N). Figure 15Figure (c) shows the short-circuit current and charge transfer diagrams under different applied forces (1N to 20N). Figure 15 Figure (d) shows the linear relationship between open-circuit voltage and applied force. Figure 15 Figure (e) shows the open-circuit voltage of the aerogel-based triboelectric nanogenerator prepared in Example 1 during 13,000 cycles.

[0080] like Figure 15 As shown, the increased force leads to a tighter contact between the positive and negative friction layers and a larger effective contact area, thereby enhancing the triboelectric output. Therefore, the open-circuit voltage, short-circuit current, and charge transfer all increase with the applied force (1N to 20N), with maximum output values ​​of 442.9V, 4.68μA, and 131.2nC, respectively. Simultaneously, the fiber profile and uneven microstructure of the aerogel surface in Example 1 exhibit good pressure sensitivity within a certain force range. Fitting calculations show that its pressure sensitivity in the 1N to 10N range is 20.65V / N, providing performance assurance for subsequent sensing applications.

[0081] like Figure 15 As shown in Figure (e), after 13,000 cycles, the aerogel-based triboelectric nanogenerator prepared in Example 1 still maintains stable electrical output and has excellent fatigue resistance.

[0082] Please see Figure 16 , Figure 16 The diagram shows the open-circuit voltage, short-circuit current, and output power density of the aerogel-based triboelectric nanogenerator prepared in Example 1 of this invention under an external variable resistor.

[0083] In addition, such as Figure 16 As shown, connect it to 10 4 Up to 10 9 When the resistance is Ω, the open-circuit voltage increases with increasing resistance, and the short-circuit current decreases with increasing resistance. When the resistance is 20MΩ, the peak power density reaches 165.7μW / cm².

[0084] Please see Figure 17 , Figure 17 The graph shows the triboelectric output performance of the aerogel-based triboelectric nanogenerator prepared in Example 1 of this invention under different relative humidity environments. Figure 17 Figure (a) shows the open-circuit voltage of the aerogel-based triboelectric nanogenerator prepared in Example 1 under different humidity conditions. Figure 17 Figure (b) shows the short-circuit current of the aerogel-based triboelectric nanogenerator prepared in Example 1 under different humidity conditions.

[0085] like Figure 17As shown, an aerogel-based triboelectric nanogenerator of Example 1 was assembled using an aerogel with a surface area of ​​5 cm² × 5 cm² as the triboelectric positive electrode material and a polytetrafluoroethylene film as the negative electrode material. It was sealed in a container to control internal humidity changes, and its triboelectric output performance under different humidity environments was tested at 1.9 Hz and 8 N. Figure 17 Figure (a) and Figure 17 As shown in Figure (b), the output voltage and current trends are consistent with the humidity changes.

[0086] Please see Figure 18 , Figure 18 This is a schematic diagram showing how the aerogel-based triboelectric nanogenerator prepared in Example 1 of the present invention enhances electrical output in a humid environment by forming hydrogen bonds at the interface, which in turn binds water and ion channels.

[0087] Figure 18 As shown, due to the abundance of hydrophilic groups such as hydroxyl groups in aerogels and their porous structure, a large number of water molecules form bound water on the surface and inside of the aerogel in low and medium humidity ranges. Cations and metal ions further promote charge transfer, thus increasing the electrical output of the triboelectric nanogenerator. Figure 17 Figure (a) and Figure 17 As shown in Figure (b), from 30%RH to 80%RH, the voltage increases from 99.2V to 147.3V and the current increases from 0.71μA to 0.95μA. However, at 90%RH, the excess water molecules exist in the free water state, and the charge dissipation increases and becomes the dominant factor. The electrostatic shielding effect is enhanced, resulting in a significant decrease in the electrical output of the triboelectric nanogenerator. At this time, the voltage and current drop to 107.6V and 0.76μA, respectively.

[0088] Please see Figure 19 , Figure 19 This is a wet sensing sensitivity diagram of the aerogel-based triboelectric nanogenerator prepared in Example 1 of the present invention; Figure 19 Figure (a) in the figure is a fitting curve of the open circuit voltage and short circuit current of the aerogel-based triboelectric nanogenerator prepared in Example 1 as a function of humidity in the range of relative humidity from 30% to 80%. Figure 19 Figure (b) shows the open-circuit voltage response of the aerogel-based triboelectric nanogenerator prepared in Example 1 during humidification or dehumidification.

[0089] Depend on Figure 19 As shown in Figure (a), the humidity sensitivity of open-circuit voltage and short-circuit current in the range of 30%RH to 80%RH is 0.985V / %RH (R 2 =0.984) and 0.005μA / %RH (R 2=0.996), indicating that it has excellent humidity sensing performance within this humidity range; by Figure 19 As shown in Figure (b), when the ambient humidity decreases from 90%RH to 30%RH, the open-circuit voltage first increases and then decreases, which is opposite to the trend of the ambient humidity increase process. Furthermore, the output voltage changes very little during the moisture absorption and dehumidification processes, indicating that the aerogel-based triboelectric nanogenerator of Example 1 has reversible humidity response.

[0090] Please see Figure 20 and Figure 21 , Figure 20 The open-circuit voltage diagram of the aerogel-based triboelectric nanogenerator prepared in Example 1 of the present invention after 14,000 contact-separation cycles at 83% relative humidity. Figure 21 The real-time open-circuit voltage of the aerogel-based triboelectric nanogenerator prepared in Example 1 of the present invention is obtained by intermittently exhaling air into the triboelectric layer during the operation driven by a commercial exciter.

[0091] like Figure 20 As shown, after 14,000 contact-separation cycles at 83% RH, the open-circuit voltage remained stable without significant change, demonstrating high humidity durability. When breath was exhaled onto the aerogel-based triboelectric nanogenerator of Example 1, which is driven by a commercial vibrator, the output voltage exhibited a trend of first increasing and then decreasing, with the electrical signal variation amplitude remaining stable (e.g., ...). Figure 21 As shown in the figure, the aerogel of Example 1 has the potential to monitor respiration.

[0092] Please see Figure 22 , Figure 22 This is a product application diagram of the aerogel-based triboelectric nanogenerator prepared in Example 1 of the present invention. Figure 22 Figure (a) shows a schematic diagram of powering 632 LEDs. Figure 22 Figure (b) shows the charging curves of commercial capacitors ranging from 0.22 μF to 10 μF. Figure 22 Figure (c) in the diagram is a schematic diagram of the process of powering an electronic stopwatch that requires a 3V power supply.

[0093] The aerogel-based triboelectric nanogenerator of this embodiment can be applied to capacitor charging, electronic stopwatches, wireless sensors for detecting human movement, and burglar alarms due to its energy harvesting and intelligent sensing capabilities.

[0094] like Figure 22 As shown in Figure a, a 5cm²×5cm² device can simultaneously light up 632 LEDs.

[0095] like Figure 22 As shown in b, after the AC power is converted to DC power by the bridge rectifier, it can charge commercial capacitors ranging from 0.22μF to 10μF.

[0096] like Figure 22 As shown in c, it can also drive an electronic stopwatch that requires a 3V power supply, demonstrating its energy harvesting potential.

[0097] Please see Figure 23 , Figure 23 The diagram shows the output voltage of the aerogel-based triboelectric nanogenerator prepared in Example 1 of this invention as a sensor for detecting human motion. Figure 23 Figure (a) shows the output voltage as a contact sensor for detecting human movement. Figure 23 Figure (b) shows the output voltage as a non-contact sensor for detecting human motion.

[0098] In addition to energy harvesting, such as Figure 23 As shown, this triboelectric nanogenerator can be used as a wireless sensor to detect human movement. Its working principle is as follows: when a foot touches a 3.5cm²×3.5cm² triboelectric nanogenerator or passes a 5cm²×5cm² single-electrode triboelectric nanogenerator from 1m away, the output voltage signal is converted into a square wave by the processing circuit. This signal is counted by a microcontroller and transmitted wirelessly. Another microcontroller then triggers a buzzer and a digital display. The signal strength reflects the movement state. Figure 23 In Figure (a), when the sensor is in motion, the output voltages for walking, running, and jumping are 121.8V, 151.1V, and 182.3V, respectively; Figure 23 Figure (b) shows the values ​​of 1.8V, 2.6V, and 3.5V for non-contact sensing, respectively, which verifies the feasibility of human motion monitoring.

[0099] Please see Figure 24 , Figure 24 This diagram shows the application of the aerogel-based triboelectric nanogenerator prepared in Example 1 of this invention in a burglar alarm. Figure 24 Figure (a) in the figure is a schematic diagram of the aerogel-based triboelectric nanogenerator prepared in Example 1 as a burglar alarm. Figure 24 Figure (b) in the diagram is a schematic diagram of the operation of the simulated alarm.

[0100] like Figure 24 As shown, the anti-theft alarm developed using aerogel-based triboelectric nanogenerators can be placed under a doormat. When someone steps on or approaches, the triboelectric nanogenerator triggers a voltage signal, activating a buzzer and digital display, providing a voice alarm and showing the location.

[0101] Please see Figure 25 , Figure 25 The open-circuit voltage diagram of an aerogel-based triboelectric nanogenerator prepared using the process of Example 1 of this invention from wood ash made from different varieties of fallen leaves.

[0102] The fallen leaves in this embodiment are one of the following: Euonymus japonicus, Ilex chinensis, Broussonetia papyrifera, Eriobotrya japonica, Livistona chinensis, Sycamorea foetida, and Camphora chinensis.

[0103] Specifically, the fallen leaves of Euonymus japonicus, Broussonetia papyrifera, Eriobotrya japonica, Livistona chinensis, and Cinnamomum camphora were used to make plant ash. Aerogels from different plant ash sources were prepared using the same component ratio and process route as in Example 1 and assembled into triboelectric nanogenerators in a vertical contact separation mode. The output voltage was measured, and the results showed that the voltage output varied depending on the type of leaf but all had good output performance, proving that the preparation method of the present invention has scalability and universality.

[0104] Please see Figure 26 , Figure 26 This is a diagram illustrating the degradation process of the aerogel prepared in Example 1 of the present invention.

[0105] like Figure 26 As shown, when Example 1 was buried in outdoor soil, the aerogel prepared in Example 1 dried but remained structurally intact after one month. After five months, the aerogel split into small pieces. After six months, many small pores appeared on the small pieces, and some of the previously observed small pieces had disappeared. This indicates that the aerogel has undergone partial degradation and that the degradation process is still ongoing. Thus, it can be seen that the aerogel has good biodegradability and high-standard environmental protection characteristics.

[0106] Please see Figure 27 , Figure 27 This is a comparison chart of the electrical output performance of the aerogel-based triboelectric nanogenerator prepared by multiple recycling of the aerogel in Example 1 of this invention. Figure 27 Figure (a) in the figure is a comparison of open-circuit voltages. Figure 27 Figure (b) in the diagram is a comparison of short-circuit currents. Figure 27 Figure (c) in the figure is a comparison of charge transfer amounts.

[0107] like Figure 27 As shown, the aerogel from the aerogel-based triboelectric nanogenerator of Example 1 and the remaining aerogel scraps were left to stand normally for 60 days, then remixed to prepare aerogel samples, which were assembled into a vertically contact-separated triboelectric nanogenerator with an output voltage of 438.2V, an output current of 3.81μA, and a charge transfer of 122.8nC. The voltage of the triboelectric nanogenerator assembled from the aerogel of Example 1 after three cycles of preparation decreased by only 5.9%, the current decreased by 39.7%, and the transferred charge decreased by 27.0%.

[0108] In summary, by using quaternary ammonium salt modified cellulose and microfibrillated cellulose as a framework with multi-scale fiber entanglement, adding wood ash from fallen leaves combustion, and then rapidly dehydrating, freezing, and drying at room temperature, an aerogel with excellent mechanical properties, recyclability, and biodegradability is prepared, thus achieving the processing of cellulose aerogels with high humidity adaptability, high output, recyclability, and biodegradability.

[0109] It should be noted that when numerical ranges are involved in this invention, it should be understood that the two endpoints of each numerical range and any value between the two endpoints can be selected. Since the steps and methods used are the same as those in the embodiments, preferred embodiments are described in order to avoid redundancy. Although preferred embodiments of this invention have been described, those skilled in the art can make other changes and modifications to these embodiments once they know the basic inventive concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of this invention.

[0110] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from the spirit and scope of this invention; if these modifications and variations of this invention fall within the scope of the claims of this invention and their equivalents, then this invention also intends to include these modifications and variations.

Claims

1. A method for preparing a cellulose-based composite material filled with plant ash, characterized in that, Includes the following steps: S10: Prepare an aqueous solution of (3-chloro-2-hydroxypropyl)trimethylammonium chloride, add a strong base, and stir for the first time to form a quaternary ammonium salt solution; S20: Take softwood pulp, homogenize it to form cellulose fibers, add it to the quaternary ammonium salt solution, stir and heat it for a second time, and then wash it with water to form quaternary ammonium salt modified cellulose. S30: Take microfibrillated cellulose, wood ash and deionized water, mix them with the quaternary ammonium salt modified cellulose, and stir for a third time to obtain the composite material.

2. The method for preparing the cellulose-based composite material filled with plant ash according to claim 1, characterized in that, The microfibrillated cellulose has a fiber width of 50 nm to 200 nm and a fiber length of 20 μm to 500 μm.

3. The method for preparing the cellulose-based composite material filled with plant ash according to claim 1, characterized in that, The aqueous solution has a volume of 80 mL to 140 mL, and contains 1.4 g to 6.0 g of the (3-chloro-2-hydroxypropyl)trimethylammonium chloride.

4. The method for preparing the cellulose-based composite material filled with plant ash according to claim 1, characterized in that, The mass ratio of the strong base to the cellulose fiber in the quaternary ammonium salt modified cellulose is 1.0g to 1.2g: 1.8g to 3.0g.

5. The method for preparing the cellulose-based composite material filled with plant ash according to claim 1 or 4, characterized in that, The strong base is sodium hydroxide or potassium hydroxide.

6. The method for preparing the cellulose-based composite material filled with plant ash according to claim 1, characterized in that, The volume of the deionized water is 200 mL to 400 mL, the mass of the microfibrillated cellulose used is 0.6 g to 1.8 g, and the mass of the wood ash used is 0.36 g to 1.08 g.

7. The method for preparing the cellulose-based composite material filled with plant ash according to claim 1, characterized in that, The plant ash is obtained by washing, drying, burning and grinding fallen leaves into ash. The fallen leaves are at least one of the following: Euonymus japonicus, Ilex chinensis, Broussonetia papyrifera, Eriobotrya japonica, Livistona chinensis, Pterocarya stenoptera, or Camphor tree leaves.

8. The method for preparing the cellulose-based composite material filled with plant ash according to claim 1, characterized in that, The second stirring and heating is performed by stirring at a speed of 40 to 50 r / min at a temperature of 65 to 75°C for 50 to 70 minutes.

9. An aerogel of a cellulose-based composite material filled with plant ash, characterized in that, The preparation process of the aerogel is as follows: the composite material obtained by the preparation method according to any one of claims 1 to 8 is placed in a solvent-draining tool to drain the solvent, and then dried to obtain the aerogel.

10. The aerogel of the cellulose-based composite material filled with plant ash according to claim 9, characterized in that, The drying process involves freezing at -18°C to -5°C for 2.0 to 4.5 hours, then drying at 55°C to 65°C for 20 to 35 minutes, followed by extrusion, and finally drying at 55°C to 65°C for 6 to 8 hours.

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