Two-dimensional nanocomposite, three-dimensional bulk phase material, and preparation method and application of two-dimensional nanocomposite and three-dimensional bulk phase material

Abstract

The invention provides a two-dimensional nano composite material, a three-dimensional bulk phase material and a preparation method and application thereof, and the preparation method of the two-dimensional nano composite material comprises the following steps: under a stirring condition, mixing a composite nanosheet with an aqueous solution of an organic phase to form slurry, and then carrying out evaporation induced self-assembly to obtain the two-dimensional nano composite material. According to the application, calcium phosphate nano-clusters are introduced between two-dimensional nanosheet layers, and in the evaporation self-assembly process, the nano-clusters are subjected to in-situ inorganic ion polymerization under the regulation and control of polyvinyl alcohol and sodium alginate molecular chains to form hydroxyapatite nanowires; on one hand, the hydroxyapatite nanowire is combined with carboxyl of sodium alginate through an ionic bond, and on the other hand, the hydroxyapatite nanowire interacts with hydroxyl of polyvinyl alcohol through a hydrogen bond, so that a firm organic-inorganic double-bridge structure is constructed between adjacent nanosheets. The two-dimensional nano composite material prepared by the method has relatively high tensile strength, fracture performance and toughness.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of materials, and relates to a two-dimensional nanocomposite material, a three-dimensional bulk material and a preparation method and application thereof. BACKGROUND

[0002] Two-dimensional nanomaterials, such as graphene oxide, montmorillonite and the like, are considered to be ideal building units for constructing high-performance nanocomposites due to excellent mechanical properties, large specific surface area and high aspect ratio. Inspired by the “brick-mud” microstructure of natural nacre, researchers have prepared a series of biomimetic layered nanocomposites by compounding two-dimensional nanosheets with a polymer matrix.

[0003] However, the performance of the material is still far below the theoretical value, and the main bottleneck is that the interface interaction between the two-dimensional nanosheet and the polymer matrix is weak, resulting in low stress transfer efficiency. Although the introduction of ion crosslinking or polymer bridging molecules can enhance the interface interaction to a certain extent, the toughness of the obtained material is usually difficult to break through 40 MJm⁻³, and the fracture strain is also low (<10%), which limits its application in the field of structural engineering which requires high energy absorption and high toughness.

[0004] Therefore, it is necessary to develop a new two-dimensional nanocomposite material. SUMMARY

[0005] In view of the deficiencies in the prior art, the application provides a two-dimensional nanocomposite material, a three-dimensional bulk material and a preparation method and application thereof. The two-dimensional nanocomposite material has a unique organic-inorganic double-bridge interface design, and the macroscopic mechanical properties of the material, especially the toughness, are significantly improved.

[0006] To achieve this purpose, the application adopts the following technical solutions: One of the purposes of the application is to provide a preparation method of a two-dimensional nanocomposite material, comprising the following steps: Under stirring, the composite nanosheet is mixed with an aqueous solution of an organic phase to form a slurry, and then evaporation-induced self-assembly is performed to obtain a two-dimensional nanocomposite material.

[0007] Preferably, the preparation method of the composite nanosheet comprises: compounding calcium phosphate nanoclusters with two-dimensional nanosheets to form a composite nanosheet.

[0008] Preferably, the two-dimensional nanosheet comprises any one or a combination of at least two of montmorillonite nanosheets, mica nanosheets, calcium phosphate nanosheets, calcium carbonate nanosheets or graphene oxide nanosheets; Preferably, the thickness of the two-dimensional nanosheet is 1-10 nm, and the lateral size is 100-1000 nm; Preferably, the mass ratio of the calcium phosphate nanoclusters to the two-dimensional nanosheets is 1:(2-5). Preferably, the complexing mode is hydrogen bond complexing.

[0009] Preferably, the preparation method of the calcium phosphate nanoclusters comprises: reacting a phosphorus source and a calcium source in an organic solvent with triethylamine as a stabilizer to obtain inorganic ion nanoclusters. Preferably, the organic solvent comprises any one or a combination of at least two of ethanol, ethylene glycol or glycerol. Preferably, the reaction temperature is 20-25℃, and the reaction time is 4-6 h.

[0010] Preferably, the phosphorus source comprises phosphoric acid, and the calcium source comprises calcium chloride dihydrate. Preferably, the concentration of the calcium source in the organic solvent is 0.001-0.1 mol / L. Preferably, the molar ratio of the calcium source to the phosphorus source is (1-2):1. Preferably, the concentration of the triethylamine in the organic solvent is 0.02-1 mol / L.

[0011] Preferably, the organic phase comprises a combination of polyvinyl alcohol and sodium alginate. Preferably, the concentration of the polyvinyl alcohol in water is 1-10 wt%. Preferably, the concentration of the sodium alginate in water is 0.1-2 wt%. Preferably, the mass ratio of the complexed nanosheets to the organic phase is (3-7):(7-3). Preferably, the stirring rate is 1200-1800 rpm. Preferably, the mixing time is 3-8 h. Preferably, the temperature of the evaporation-induced self-assembly is 20-30℃.

[0012] The second object of the present application is to provide a two-dimensional nanocomposite material prepared by the preparation method according to the first object.

[0013] The third object of the present application is to provide a preparation method of a three-dimensional bulk material, which comprises: stacking at least two pieces of the two-dimensional nanocomposite material prepared according to the first object, and pasting adjacent two pieces of the two-dimensional nanocomposite material through a complex adhesive to obtain a three-dimensional bulk material; Preferably, the lamination pressure is 5-50 kPa, and the lamination time is 12-48 h.

[0014] Preferably, the method for preparing the composite adhesive includes: mixing calcium phosphate nanoclusters, polyvinyl alcohol, and sodium alginate to form a composite adhesive; Preferably, the concentration of the calcium phosphate nanoclusters in the composite adhesive is 10-30 wt%. Preferably, the mass ratio of polyvinyl alcohol to sodium alginate is (4-7):1.

[0015] The fourth objective of this invention is to prepare a three-dimensional bulk material by the preparation method described in claim 3.

[0016] The fifth objective of this invention is the application of the two-dimensional nanocomposite material described in objective two, or the three-dimensional bulk material described in objective four, in the preparation of protective materials, flexible armor components, and soft robots.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: In this application, calcium phosphate nanoclusters are introduced into the interlayer of two-dimensional nanosheets. During the evaporation self-assembly process, these nanoclusters undergo in-situ inorganic ionic polymerization under the regulation of polyvinyl alcohol and sodium alginate molecular chains, forming hydroxyapatite nanowires. These hydroxyapatite nanowires are bonded to the carboxyl groups of sodium alginate via ionic bonds and interact with the hydroxyl groups of polyvinyl alcohol via hydrogen bonds, thereby constructing a robust "organic-inorganic double-bridge" structure between adjacent nanosheets. The two-dimensional nanocomposite material prepared by this method exhibits strong tensile strength, fracture properties, and toughness. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the process flow for preparing two-dimensional nanocomposite materials in Example 1; Figure 2 The image shows a flexibility test result of the two-dimensional nanocomposite material prepared in Example 1. Figure 3 The tensile strength versus fracture strain curve of the two-dimensional nanocomposite film prepared in Example 1; Figure 4 The mechanical properties of the two-dimensional nanocomposite films prepared in Example 1 and Comparative Examples 1-2 are shown in the graph. Figure 5 This is a schematic diagram of the process flow for preparing the three-dimensional bulk material in Example 4; Figure 6 The image shows the flexibility test results of the three-dimensional bulk material prepared in Example 4. Figure 7 The bending strength versus bending strain curve of the three-dimensional bulk material prepared in Example 4; Figure 8 Toughness test results of the three-dimensional bulk material prepared in Example 4 under high and low temperature conditions. Detailed Implementation

[0019] It should be understood that in the description of this invention, the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," etc., 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 with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0020] It should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "set," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0021] Those skilled in the art should understand that the present invention necessarily includes the necessary pipelines, conventional valves and general pump equipment for achieving complete process, but the above content is not the main innovation of the present invention. Those skilled in the art can add layouts based on process flow and equipment structure selection, and the present invention does not make any special requirements or specific limitations in this regard.

[0022] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0023] In some embodiments, this application provides a method for preparing a two-dimensional nanocomposite material, comprising the following steps: Under stirring conditions, composite nanosheets are mixed with an aqueous solution of an organic phase to form a slurry, which is then subjected to evaporation-induced self-assembly to obtain a two-dimensional nanocomposite material.

[0024] In this application, by mixing specific types of composite nanosheets with an aqueous solution of an organic phase, a robust "organic-inorganic double bridge" structure can be established through evaporation-induced self-assembly, thereby improving the tensile strength, fracture strength, and toughness of two-dimensional nanocomposites.

[0025] In some embodiments, the method for preparing the composite nanosheets includes: combining calcium phosphate nanoclusters with two-dimensional nanosheets to form composite nanosheets.

[0026] In this application, the composite nanosheets are made by introducing calcium phosphate nanoclusters into the interlayer of two-dimensional nanosheets. During the evaporation self-assembly process, the nanoclusters undergo in-situ inorganic ionic polymerization under the regulation of polyvinyl alcohol and sodium alginate molecular chains to form hydroxyapatite nanowires. The hydroxyapatite nanowires are bonded to the carboxyl groups of sodium alginate through ionic bonds and interact with the hydroxyl groups of polyvinyl alcohol through hydrogen bonds, thereby constructing a strong "organic-inorganic double bridge" structure between adjacent nanosheets. This results in a two-dimensional nanocomposite material with strong tensile strength, fracture properties, and toughness.

[0027] In some embodiments, the two-dimensional nanosheets include any one or a combination of at least two of montmorillonite nanosheets, mica nanosheets, calcium phosphate nanosheets, calcium carbonate nanosheets, or graphene oxide nanosheets. In some embodiments, the thickness of the two-dimensional nanosheet is 1-10 nm (e.g., 1 nm, 3 nm, 5 nm, 7 nm, 10 nm, etc.), and the lateral dimension is 100-1000 nm (e.g., 100 nm, 300 nm, 500 nm, 700 nm, 1000 nm, etc.). It should be noted that the lateral dimension here refers to the length and width of the two-dimensional nanosheet.

[0028] In some embodiments, the mass ratio of the calcium phosphate nanoclusters to the two-dimensional nanosheets is 1:(2-5) (e.g., 1:2, 1:3, 1:4, 1:5, etc.). In some embodiments, the composite is a hydrogen bond composite.

[0029] In some embodiments, the method for preparing the calcium phosphate nanoclusters includes: reacting a phosphorus source with a calcium source in an organic solvent using triethylamine as a stabilizer to obtain inorganic ionic nanoclusters; In this application, by controlling the reaction between calcium and phosphorus sources in an organic solvent and in the presence of a triethylamine stabilizer, ultra-small (approximately 1.70 nm) calcium phosphate nanoclusters can be stably generated. These calcium phosphate nanoclusters possess high reactivity due to their small size effect and high specific surface area, making them easy to interact with nanosheets and polymers, thus providing a basis for subsequent interface modification and in-situ reactions.

[0030] In some embodiments, the organic solvent includes any one or a combination of at least two of ethanol, ethylene glycol, or glycerol; In some embodiments, the reaction temperature is 20-25°C (e.g., 20°C, 22°C, 25°C, etc.), and the reaction time is 4-6 h (e.g., 4 h, 4.5 h, 5 h, 5.5 h, 6 h, etc.).

[0031] In some embodiments, the phosphorus source includes phosphoric acid, and the calcium source includes calcium chloride dihydrate; In some embodiments, the concentration of the calcium source in the organic solvent is 0.001-0.1 mol / L (e.g., 0.001 mol / L, 0.005 mol / L, 0.01 mol / L, 0.03 mol / L, 0.05 mol / L, 0.08 mol / L, 0.1 mol / L, etc.). In some embodiments, the molar ratio of the calcium source to the phosphorus source is (1-2):1 (e.g., 1:1, 1.2:1, 1.5:1, 1.8:1, 2:1, etc.). In some embodiments, the concentration of triethylamine in the organic solvent is 0.02-1 mol / L (e.g., 0.02 mol / L, 0.05 mol / L, 0.08 mol / L, 0.1 mol / L, 0.3 mol / L, 0.5 mol / L, 0.8 mol / L, 1 mol / L, etc.).

[0032] In some embodiments, the organic phase comprises a combination of polyvinyl alcohol and sodium alginate; In this application, polyvinyl alcohol (PVA) provides abundant hydroxyl groups, primarily forming hydrogen bonds; sodium alginate (SA) provides carboxyl anions. The two work synergistically, with PVA acting as a flexible matrix and hydrogen bond provider, and SA acting as a "regulator" for ionic bonding with the inorganic phase and controlling the in-situ polymerization of calcium phosphate nanoclusters, thereby constructing an "organic-inorganic double-bridge" structure, which enhances the tensile strength, fracture strength, and toughness of the two-dimensional nanocomposite material.

[0033] In some embodiments, the concentration of polyvinyl alcohol in water is 1-10 wt% (e.g., 1 wt%, 3 wt%, 5 wt%, 7 wt%, 10 wt%, etc.). In some embodiments, the concentration of sodium alginate in water is 0.1-2 wt% (e.g., 0.1 wt%, 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, etc.). In some embodiments, the mass ratio of the composite nanosheets to the organic phase is (3-7):(7-3) (e.g., 3:7, 4:6, 5:5, 6:4, 7:3, etc.). In some embodiments, the stirring rate is 1200-1800 rpm (e.g., 1200 rpm, 1300 rpm, 1400 rpm, 1500 rpm, 1600 rpm, 1700 rpm, 1800 rpm, etc.). In some embodiments, the mixing time is 3-8 h (e.g., 3 h, 5 h, 8 h, etc.). In some embodiments, the temperature for evaporation-induced self-assembly is 20-30°C (e.g., 20°C, 22°C, 25°C, 28°C, 30°C, etc.).

[0034] In some embodiments, this application provides a method for preparing a three-dimensional bulk material, the method comprising: At least two two-dimensional nanocomposite materials prepared from one of the targets are stacked together, and adjacent two two-dimensional nanocomposite materials are bonded together with a composite adhesive and laminated to obtain a three-dimensional bulk material. In some embodiments, a three-dimensional bulk material is constructed by using a layer-by-layer assembly technique and bonding between layers with a specific adhesive. Under pressure, the components in the adhesive diffuse to the interface to form strong chemical bonds and physical entanglements, thereby broadening the application range of two-dimensional nanocomposite films.

[0035] In some embodiments, the lamination pressure is 5-50 kPa (e.g., 5 kPa, 10 kPa, 15 kPa, 20 kPa, 25 kPa, 30 kPa, 35 kPa, 40 kPa, 45 kPa, 50 kPa, etc.), and the lamination time is 12-48 h (e.g., 12 h, 16 h, 20 h, 24 h, 28 h, 32 h, 36 h, 40 h, 44 h, 48 h, etc.).

[0036] In some embodiments, the method for preparing the composite adhesive includes: mixing calcium phosphate nanoclusters, polyvinyl alcohol, and sodium alginate to form a composite adhesive; In some embodiments, the concentration of the calcium phosphate nanoclusters in the composite adhesive is 10-30 wt% (e.g., 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, etc.). In some embodiments, the mass ratio of polyvinyl alcohol to sodium alginate is (4-7):1 (e.g., 4:1, 5:1, 6:1, 7:1, etc.).

[0037] Example 1 This embodiment provides a method for preparing two-dimensional nanocomposite materials, such as... Figure 1 As shown, it includes: (1) Preparation of montmorillonite nanosheet dispersion: Take 2 wt% montmorillonite aqueous solution and stir vigorously at room temperature for 7 days. After standing for 24 hours, collect the upper suspension, sonicate for 30 minutes, and then centrifuge at 3000 rpm for 5 minutes to remove unpeeled particles, to obtain a 1 wt% montmorillonite nanosheet aqueous dispersion. Soluble this aqueous dispersion with anhydrous ethanol to obtain a 10 mg / mL montmorillonite nanosheet ethanol dispersion for later use.

[0038] (2) Synthesis of calcium phosphate nanoclusters: 11.76 g of calcium chloride dihydrate was weighed and dissolved in 1.28 L of anhydrous ethanol to prepare a clear solution. At 25°C, under continuous magnetic stirring, 177.43 mL of triethylamine was added to the solution, and stirring continued for 30 minutes. Subsequently, 3.34 mL of phosphoric acid was dissolved in 64 mL of ethanol and slowly added dropwise to the above mixture using a constant pressure dropping funnel. After the addition was complete, vigorous stirring continued for 12 hours. After the reaction was completed, the mixture was centrifuged at 6000 rpm for 5 minutes to obtain a white precipitate. The precipitate was washed three times with anhydrous ethanol, and finally, the obtained calcium phosphate nanoclusters were redispersed in ethanol to prepare a concentration of 10 mg / mL.

[0039] (3) Preparation of composite nanosheets: Measure 20 mL of the obtained calcium phosphate nanocluster ethanol dispersion (10 mg / mL) and mix evenly with 80 mL of the montmorillonite nanosheet ethanol dispersion (10 mg / mL) obtained in step (1) (mass ratio 1:4). Stir at 500 rpm for 30 minutes at room temperature to allow the calcium phosphate nanoclusters to be fully anchored on the surface of the montmorillonite nanosheets through intermolecular hydrogen bonds.

[0040] (4) Preparation of two-dimensional nanocomposite films: Measure 20 mL of a 5.0 wt% polyvinyl alcohol aqueous solution and 20 mL of a 1.0 wt% sodium alginate aqueous solution, and mix them evenly. Centrifuge the composite nanosheet mixture obtained in step (3) at 6000 rpm for 5 minutes to collect the precipitate, and add this precipitate to the above polyvinyl alcohol / sodium alginate mixed solution (at this time, the mass ratio of inorganic phase to organic phase is 5:6). Stir the mixture vigorously at 1500 rpm for 6 hours at 25°C to form a uniform and stable slurry. Transfer the slurry to a 12 cm × 12 cm square petri dish, and control the slurry depth to about 8 mm. Then place it in a 25°C, vibration-free environment to perform evaporation-induced self-assembly. After about 3 days, the solvent completely evaporates, and the self-supporting two-dimensional nanocomposite film is peeled off from the petri dish.

[0041] Figure 2 The image shows the flexibility test results of the two-dimensional nanocomposite film prepared in Example 1. Figure 2It can be seen that the two-dimensional nanocomposite film prepared in this embodiment has good bending, torsion and load-bearing effects.

[0042] Figure 3 The tensile strength and fracture strain curves of the two-dimensional nanocomposite film prepared in Example 1 show that its tensile strength is 292.8 MPa and its fracture strain is 52.5%.

[0043] Figure 4 The graph shows the mechanical properties of the two-dimensional nanocomposite film prepared in Example 1. Figure 4 It can be seen that the tensile strength of this two-dimensional nanocomposite film is 292.8 MPa, and the toughness is 111.7 MJ / m. -3 .

[0044] Example 2 This embodiment provides a method for preparing a two-dimensional nanocomposite film, including: (1) Preparation of graphene oxide nanosheet dispersion: Purchase commercially available graphene oxide aqueous dispersion (2 mg / mL), centrifuge at 4000 rpm for 10 minutes to remove large particles, take the supernatant to obtain an aqueous dispersion of graphene oxide nanosheets with a concentration of 1.5 mg / mL for later use. Its thickness is about 1 nm and its lateral dimension is about 700 nm.

[0045] (2) Synthesis of calcium phosphate nanoclusters: Weigh 0.294 g of calcium chloride dihydrate and dissolve it in 2.0 L of anhydrous ethanol (calcium source concentration approximately 0.001 mol / L). At 20 °C, with continuous magnetic stirring, add 4.4 mL of triethylamine (triethylamine concentration approximately 0.016 mol / L) to the solution and continue stirring for 30 minutes. Then, dissolve 0.083 mL of phosphoric acid in 20 mL of ethanol and slowly add it dropwise to the above mixed solution using a constant pressure dropping funnel (calcium-phosphorus molar ratio approximately 2:1). After the addition is complete, continue vigorous stirring for 24 hours. After the reaction is complete, centrifuge at 6000 rpm for 5 minutes to obtain a white precipitate. Wash the precipitate three times with anhydrous ethanol, and finally redisperse the obtained calcium phosphate nanoclusters in ethanol to prepare a concentration of 1 mg / mL.

[0046] (3) Preparation of composite nanosheets: 90 mL of the obtained calcium phosphate nanocluster ethanol dispersion (1 mg / mL) and 20 mL of the graphene oxide nanosheet aqueous dispersion obtained in step (1) (1.5 mg / mL, pre-exchanged to ethanol) were mixed evenly (the mass ratio of calcium phosphate nanoclusters to nanosheets was approximately 1:3, close to the upper limit of 1:2). The mixture was stirred at 300 rpm for 30 minutes at room temperature to allow the calcium phosphate nanoclusters to be fully anchored on the surface of the graphene oxide nanosheets through intermolecular hydrogen bonds.

[0047] (4) Preparation of two-dimensional nanocomposite films: Measure 15 mL of a 1.0 wt% polyvinyl alcohol aqueous solution and 15 mL of a 0.1 wt% sodium alginate aqueous solution, and mix them evenly. Centrifuge the composite nanosheet mixture obtained in step (3) at 6000 rpm for 5 minutes to collect the precipitate, and add this precipitate to the above polyvinyl alcohol / sodium alginate mixed solution (at this time, the mass ratio of inorganic phase to organic phase is 2:3). Stir the mixture vigorously at 1200 rpm at 20℃ for 5 hours to form a uniform and stable slurry. Transfer the slurry to a 9 cm × 9 cm square petri dish, and control the slurry depth to about 5 mm. Then place it in a 20℃, vibration-free environment to perform evaporation-induced self-assembly. After about 5 days, the solvent completely evaporates, and the self-supporting two-dimensional nanocomposite film is obtained by peeling it off from the petri dish.

[0048] The two-dimensional nanocomposite film prepared in Example 2 was tested using the same methods as in Example 1. The results showed that the strength of Example 2 was 373.5 MPa and the toughness was 101.6 MJ / m. -3 .

[0049] Example 3 This embodiment provides a method for preparing a two-dimensional nanocomposite film, including: (1) Preparation of mica nanosheet dispersion: Mica nanosheets were prepared by lithium-ion intercalation exchange to obtain a propylene glycol dispersion of mica nanosheets with a concentration of 15 mg / mL. The thickness was about 8 nm and the lateral dimension was about 800 nm.

[0050] (2) Synthesis of calcium phosphate nanoclusters: 29.4 g of calcium chloride dihydrate was weighed and dissolved in 2.0 L of ethylene glycol (calcium source concentration approximately 0.1 mol / L). At 25°C, under continuous magnetic stirring, 440 mL of triethylamine (triethylamine concentration approximately 1.6 mol / L) was added to the solution, and stirring continued for 30 minutes. Subsequently, 8.3 mL of phosphoric acid was dissolved in 100 mL of ethylene glycol and slowly added dropwise to the above mixed solution using a constant pressure dropping funnel (calcium-phosphorus molar ratio approximately 1:1). After the addition was complete, vigorous stirring continued for 6 hours. After the reaction was completed, the mixture was centrifuged at 6000 rpm for 5 minutes to obtain a white precipitate. The precipitate was washed three times with ethylene glycol, and finally, the obtained calcium phosphate nanoclusters were redispersed in ethylene glycol to prepare a concentration of 50 mg / mL.

[0051] (3) Preparation of composite nanosheets: Measure 40 mL of the obtained calcium phosphate nanoclusters in ethylene glycol (50 mg / mL) and mix them evenly with 100 mL of the mica nanosheets in propylene glycol (15 mg / mL) obtained in step (1) (the mass ratio of calcium phosphate nanoclusters to nanosheets is approximately 1:3.75, close to the upper limit of 1:5). Stir at 1000 rpm for 30 minutes at room temperature to allow the calcium phosphate nanoclusters to be fully anchored on the surface of the mica nanosheets through intermolecular hydrogen bonds.

[0052] (4) Preparation of two-dimensional nanocomposite films: Measure 25 mL of a 10.0 wt% polyvinyl alcohol aqueous solution and 25 mL of a 2.0 wt% sodium alginate aqueous solution, and mix them evenly. Centrifuge the composite nanosheet mixture obtained in step (3) at 6000 rpm for 5 minutes to collect the precipitate, and add this precipitate to the above polyvinyl alcohol / sodium alginate mixed solution (at this time, the mass ratio of inorganic phase to organic phase is 7:3). Stir the mixture vigorously at 1000 rpm at 30℃ for 3 hours (lower time limit) to form a uniform and stable slurry. Transfer the slurry to a 15 cm × 15 cm square petri dish, and control the slurry depth to about 10 mm. Then place it in a 30℃, vibration-free environment to perform evaporation-induced self-assembly. After about 2 days, the solvent completely evaporates, and the self-supporting two-dimensional nanocomposite film is obtained by peeling it off from the petri dish.

[0053] The two-dimensional nanocomposite film prepared in Example 3 was tested using the same methods as in Example 1. The results showed that the strength of Example 3 was 260.9 MPa and the toughness was 132.1 MJ / m. -3 Comparative Example 1 The difference from Example 1 is that the preparation process does not include the addition of calcium phosphate nanoclusters. Instead, the subsequent film-forming steps are carried out directly using a montmorillonite nanosheet ethanol dispersion and a polyvinyl alcohol / sodium alginate mixed solution. The remaining steps and parameters are exactly the same as in Example 1.

[0054] The product prepared in Comparative Example 1 was subjected to the same tests as in Example 1, and the results showed that the strength of Comparative Example 1 was 105.1 MPa and the toughness was 5.1 MJ / m. -3 Comparative Example 2 The difference from Example 1 is that the calcium phosphate nanoclusters were replaced with commercially available hydroxyapatite nanorods (60-80 nm) in the preparation process, while the rest of the steps and parameters were exactly the same as in Example 1.

[0055] The product prepared in Comparative Example 1 was subjected to the same tests as in Example 1, and the strength of Comparative Example 2 was found to be 92.1 MPa and the toughness was 8.2 MJ / m. -3 .

[0056] By comparing Example 1 with Comparative Examples 1 and 2, such as Figure 4 As shown, the two-dimensional nanocomposite film prepared in Example 1 exhibits high tensile strength (292.8 MPa) and ultra-high toughness (111.7 MJ / m²). - ³, significantly higher than Comparative Example 1 (strength 105.1 MPa, toughness 5.1 MJ / m). - ³) and Comparative Example 2 (strength 92.1 MPa, toughness 8.2 MJ / m) - ³). This indicates that the organic-inorganic double-bridge structure formed by introducing calcium phosphate nanoclusters and using an interlayer inorganic ion polymerization strategy can effectively enhance the mechanical properties of the material, while directly using montmorillonite nanosheets or replacing calcium phosphate nanoclusters with hydroxyapatite nanorods cannot achieve the same effect.

[0057] Example 4 This embodiment provides a method for preparing a three-dimensional bulk material, such as... Figure 5 As shown, it includes: A1. Preparation of composite adhesive: Take 300 mL of the calcium phosphate nanoclusters ethanol dispersion (10 mg / mL) prepared above, centrifuge at 6000 rpm for 5 minutes, and collect the precipitate. Add 150 mL of 1.0 wt% sodium alginate aqueous solution and 150 mL of 5.0 wt% polyvinyl alcohol aqueous solution (PVA to SA mass ratio of 5:1) to the precipitate, and stir thoroughly until a uniform viscous slurry is formed. This is the composite adhesive used for interlayer bonding (where calcium phosphate nanoclusters account for approximately 25 wt% of the total solid content of the adhesive).

[0058] A2. Preparation of Three-Dimensional Bulk Material: The two-dimensional nanocomposite film (12 cm × 12 cm) prepared in Example 1 was immersed in deionized water and allowed to swell fully to equilibrium. After removal, excess moisture was absorbed with lint-free paper. A layer of the prepared composite adhesive was uniformly coated on the surface of each film layer, and then the layers were stacked one by one until the desired thickness (e.g., 10 layers) was achieved. The stacked preforms were placed between plates, and a constant pressure of 10 kPa was applied and maintained at 25°C for 24 hours. After depressurization, the sample was allowed to air dry at 25°C for 48 hours to obtain a three-dimensional bulk material with a complete structure and tight interlayer bonding.

[0059] Figure 6 The image shows the flexibility test results of the three-dimensional bulk material prepared in Example 4, which revealed that it has good bending and torsional properties.

[0060] Figure 7 The bending strength versus bending strain curve of the three-dimensional bulk material prepared in Example 4 shows that its bending strength reaches 148.1 MPa and its bending energy is as high as 34.43 MJ / m.-3 .

[0061] Figure 8 The toughness test images of the three-dimensional bulk material prepared in Example 4 under high temperature and low temperature conditions are shown. Figure 8 It can be seen that this three-dimensional bulk material can still maintain excellent toughness under extreme temperature conditions ranging from -196°C to 200°C.

[0062] Example 5 This embodiment provides a method for preparing a three-dimensional bulk material, including: A1. Preparation of composite adhesive: Take 100 mL of the calcium phosphate nanoclusters ethanol dispersion (1 mg / mL) prepared above, centrifuge at 6000 rpm for 5 minutes, and collect the precipitate. Add 50 mL of 0.1 wt% sodium alginate aqueous solution and 50 mL of 1.0 wt% polyvinyl alcohol aqueous solution (PVA to SA mass ratio of 6:1) to the precipitate, and stir thoroughly until a uniform viscous slurry is formed. This is the composite adhesive used for interlayer bonding (where calcium phosphate nanoclusters account for approximately 10 wt% of the total solid content of the adhesive).

[0063] A2. Preparation of Three-Dimensional Bulk Material: The prepared two-dimensional nanocomposite film (9 cm × 9 cm) was immersed in deionized water to allow it to swell fully. After removal, excess moisture was absorbed with lint-free paper. A layer of the prepared composite adhesive was uniformly coated on the surface of each film layer, and then 5 layers were stacked. The stacked preform was placed between plates, and a constant pressure of 5 kPa was applied and maintained at 20°C for 48 hours. After depressurization, the sample was allowed to air dry at 20°C for 72 hours to obtain the three-dimensional bulk material.

[0064] The three-dimensional bulk material prepared in Example 5 was tested using the same method as in Example 4, and its flexural strength reached 100.3 MPa, and its flexural energy reached 18.6 MJ / m². -3 .

[0065] Example 6 This embodiment provides a method for preparing a three-dimensional bulk material, including: A1. Preparation of composite adhesive: Take 200 mL of the calcium phosphate nanoclusters ethylene glycol dispersion (50 mg / mL) prepared above, centrifuge at 6000 rpm for 5 minutes, and collect the precipitate. Add 50 mL of 2.0 wt% sodium alginate aqueous solution and 50 mL of 10.0 wt% polyvinyl alcohol aqueous solution (PVA to SA mass ratio of 5:1) to the precipitate, and stir thoroughly until a uniform viscous slurry is formed. This is the composite adhesive used for interlayer bonding (where calcium phosphate nanoclusters account for approximately 30 wt% of the total solid content of the adhesive).

[0066] A2. Preparation of Three-Dimensional Bulk Material: The two-dimensional nanocomposite film (15 cm × 15 cm) prepared above was immersed in deionized water to allow it to swell fully. After removal, excess moisture was absorbed with lint-free paper. A layer of the prepared composite adhesive was uniformly coated on the surface of each film layer, and then 15 layers were stacked. The stacked preforms were placed between plates, and a constant pressure of 50 kPa (pressure upper limit) was applied and maintained at 30°C for 12 hours. After depressurization, the sample was allowed to air dry at 30°C for 24 hours to obtain the three-dimensional bulk material.

[0067] The three-dimensional bulk material prepared in Example 6 was tested using the same method as in Example 4, and the results showed a bending strength of 160.1 MPa and a bending energy of 29.6 MJ / m². -3 .

[0068] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing a two-dimensional nanocomposite material, characterized in that, The preparation method includes the following steps: Under stirring conditions, composite nanosheets are mixed with an aqueous solution of an organic phase to form a slurry, which is then subjected to evaporation-induced self-assembly to obtain a two-dimensional nanocomposite material.

2. The preparation method according to claim 1, characterized in that, The method for preparing the composite nanosheets includes: combining calcium phosphate nanoclusters with two-dimensional nanosheets to form composite nanosheets; Preferably, the two-dimensional nanosheets include any one or a combination of at least two of montmorillonite nanosheets, mica nanosheets, calcium phosphate nanosheets, calcium carbonate nanosheets, or graphene oxide nanosheets; Preferably, the thickness of the two-dimensional nanosheet is 1-10 nm, and the lateral dimension is 100-1000 nm; Preferably, the mass ratio of the calcium phosphate nanoclusters to the two-dimensional nanosheets is 1:(2-5); Preferably, the composite process is hydrogen bonding.

3. The preparation method according to claim 2, characterized in that, The preparation method of the calcium phosphate nanoclusters includes: reacting a phosphorus source and a calcium source in an organic solvent, using triethylamine as a stabilizer, to obtain inorganic ionic nanoclusters; Preferably, the organic solvent includes any one or a combination of at least two of ethanol, ethylene glycol, or glycerol; Preferably, the reaction temperature is 20-25°C and the reaction time is 4-6 h.

4. The preparation method according to claim 3, characterized in that, The phosphorus source includes phosphoric acid, and the calcium source includes calcium chloride dihydrate; Preferably, the concentration of the calcium source in the organic solvent is 0.001-0.1 mol / L; Preferably, the molar ratio of the calcium source to the phosphorus source is (1-2):1; Preferably, the concentration of triethylamine in the organic solvent is 0.02-1 mol / L.

5. The preparation method according to claim 1, characterized in that, The organic phase comprises a combination of polyvinyl alcohol and sodium alginate; Preferably, the concentration of polyvinyl alcohol in water is 1-10 wt%; Preferably, the concentration of sodium alginate in water is 0.1-2 wt%; Preferably, the mass ratio of the composite nanosheets to the organic phase is (3-7):(7-3); Preferably, the stirring rate is 1200-1800 rpm; Preferably, the mixing time is 3-8 hours; Preferably, the temperature for evaporation-induced self-assembly is 20-30°C.

6. A two-dimensional nanocomposite material is prepared by the preparation method according to any one of claims 1-5.

7. A method for preparing a three-dimensional bulk material, characterized in that, The preparation method includes: At least two pieces of two-dimensional nanocomposite materials prepared according to claims 1-5 are stacked together, and adjacent two pieces of two-dimensional nanocomposite materials are bonded together with composite adhesive and laminated to obtain a three-dimensional bulk material. Preferably, the lamination pressure is 5-50 kPa and the lamination time is 12-48 h.

8. The preparation method according to claim 7, characterized in that, The method for preparing the composite adhesive includes: mixing calcium phosphate nanoclusters, polyvinyl alcohol and sodium alginate to form a composite adhesive; Preferably, the concentration of the calcium phosphate nanoclusters in the composite adhesive is 10-30 wt%. Preferably, the mass ratio of polyvinyl alcohol to sodium alginate is (4-7):

1.

9. A three-dimensional bulk material is prepared by the preparation method according to any one of claims 7-8.

10. The application of the two-dimensional nanocomposite material according to claim 6, or the three-dimensional bulk material according to claim 9, in the preparation of protective materials, flexible armor components, and soft robots.

Images