Method for preparing shape memory organic hydrogel with heterogeneous phase transition and application thereof

Abstract

The application relates to a preparation method and application of a shape memory organic hydrogel with heterogeneous phase change, and belongs to the technical field of material science. The organic hydrogel is prepared by a one-step emulsion thermal polymerization method, and the organic hydrogel not only has remarkable tensile property, excellent stability, thermal mechanical property and recyclability, and good shape memory effect under phase change of more than 1100%, but also has excellent electromagnetic absorption capacity and shows absorption-based electromagnetic shielding performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of material science, in particular to a preparation method of shape memory organic hydrogel with heterogeneous phase change and application thereof. BACKGROUND

[0002] With the increasing popularity of miniature electrical devices, wireless communication devices and household WIFI transmitters, electromagnetic radiation pollution problems are inevitably brought about, and may cause significant harm to human health, information security and the normal operation of precision equipment.

[0003] Traditional metal-based electromagnetic interference shielding materials, including iron, nickel, copper and silver, are developed and explored due to their high electrical conductivity for efficient electromagnetic interference shielding, which is due to the impedance mismatch between free space and shielding materials. Metals exhibit mainly reflective electromagnetic interference shielding performance by charge carriers (electrons or holes) accumulation at the dielectric interface. However, electromagnetic waves are severely reflected (usually more than 90%) at the surface of these materials, causing unbearable secondary electromagnetic radiation pollution, affecting the stability and precision of precision electronic devices.

[0004] High magnetic permeability will cause strong natural resonance and eddy current loss between the shielding material and the microwave, therefore, high magnetic permeability materials can provide more efficient electromagnetic absorption, greatly reducing secondary electromagnetic radiation. However, due to its low electrical conductivity, such materials are difficult to exhibit high electromagnetic interference shielding efficiency. On the other hand, the conductive network constructed in the electromagnetic shielding material is usually uniform with constant electrical conductivity. Absorbing-type electromagnetic interference shielding materials require good impedance matching to enable electromagnetic waves to enter the material inside and have strong electromagnetic dissipation capacity. However, good impedance matching and strong loss capacity are a pair of contradictory combinations. Good impedance matching usually means weak loss capacity, while strong loss capacity often means poor impedance matching. In addition, once the traditional shielding material is manufactured, it presents a fixed shape and cannot be re-edited and recycled, thereby causing waste of resources and hindering the flexibility and comprehensiveness of application.

[0005] Hydrogel has mechanical elasticity, flexibility, fatigue resistance and stretching performance. The network architecture of hydrogel rich in water molecules can achieve impedance matching without causing unnecessary reflection. However, the electrical conductivity of such hydrogel is usually low, leading to a trade-off between impedance matching and electrical conductivity. SUMMARY

[0006] In view of the above problems, the present application provides a preparation method of shape memory organic hydrogel with heterogeneous phase change and its application. The organic hydrogel is prepared by one-step emulsion thermal polymerization method. The organic hydrogel not only exhibits significant tensile property, excellent stability, thermal mechanical property and recyclability, and good shape memory effect under phase change of more than 1100%, but also has excellent electromagnetic absorption capacity and exhibits absorption-dominant electromagnetic shielding performance.

[0007] An object of the present application is to provide a shape memory organic hydrogel with heterogeneous phase change, which contains acrylamide, two-dimensional material MXene, nanoclay, lauryl methacrylate and paraffin wax.

[0008] The electromagnetic wave absorption rate of the organic hydrogel is 80%, the electromagnetic wave absorption temperature is 70 DEG C, and the frequency range of the electromagnetic wave is 12.4-18 GHZ.

[0009] The organic hydrogel exhibits good electromagnetic shielding performance in the Ku band, and exhibits absorption-dominant electromagnetic shielding characteristics at 70 DEG C.

[0010] Preferably, the organic hydrogel completely recovers to the original shape within 22-25 s at 70-80 DEG C.

[0011] Further, the organic hydrogel completely recovers to the original shape within 25 s at 70 DEG C.

[0012] The organic hydrogel prepared by the present application has good shape memory function to cope with complex real environment, and can completely recover to the original shape within 25 s at 70 DEG C, and has fast shape memory response capacity.

[0013] Another object of the present application is to provide a preparation method of shape memory organic hydrogel with heterogeneous phase change, which comprises:

[0014] Step 1, mixing two-dimensional material Mxene, acrylamide and nanoclay, and then adding surfactant and crosslinking agent I to obtain an aqueous solution;

[0015] Preferably, the specific steps of obtaining the aqueous solution in step 1 include:

[0016] In the two-dimensional material MXene nanosolution, acrylamide (AAm) and nanoclay are added, stirred, and then surfactant and crosslinking agent I are continuously added to obtain an aqueous solution;

[0017] Step 2, melting paraffin wax, adding lauryl methacrylate and crosslinking agent II to obtain an oil solution;

[0018] Step 3, add the aqueous solution to the oil phase solution, shear uniformly, to obtain an oil-in-water emulsion;

[0019] Step 4, in the oil-in-water emulsion, add ammonium persulfate and initiator, stir, and perform solidification crosslinking to obtain a shape memory organic hydrogel with heterogeneous phase change.

[0020] Preferably, the two-dimensional material MXene in step 1 is a metal carbide and metal nitride material with a two-dimensional layered structure;

[0021] The volume of the two-dimensional material MXene aqueous solution is 10-30 ml;

[0022] Preferably, the mass ratio of acrylamide to nanoclay in step 1 is 3-9:0.8-2.4;

[0023] Further, the mass of acrylamide is 3-9 g; the mass of nanoclay is 0.8-2.4 g;

[0024] Further, the nanoclay can be montmorillonite or halloysite;

[0025] Preferably, the stirring speed in step 1 is 500-800 rpm, the stirring time is 10-15 min, and the stirring temperature is 50-55°C;

[0026] Preferably, the surfactant in step 1 is sodium dodecyl sulfate (SDS);

[0027] Preferably, the crosslinking agent I in step 1 is N,N'-methylenebisacrylamide (MBA);

[0028] Preferably, the melting temperature in step 2 is 50-55°C;

[0029] Preferably, the crosslinking agent II in step 2 is ethylene glycol dimethacrylate;

[0030] Preferably, the mass ratio of paraffin, lauryl methacrylate, and crosslinking agent II in step 2 is 7.5-10.5:4.5-9:0.13;

[0031] Preferably, the molar mass ratio of the crosslinking agent I to the crosslinking agent II is 20:13;

[0032] Further, the mass of paraffin is 7.5-10.5 g; the mass of lauryl methacrylate LMA is 4.5-9 g;

[0033] Preferably, the mass ratio of ammonium persulfate (APS) to initiator is 3:10;

[0034] Further, the mass of the ammonium persulfate (APS) is 15-20 mg.

[0035] The initiator is 2,2-azobisisobutyronitrile (AIBN) (EGDMA);

[0036] Preferably, the stirring speed in step 2 is 500-800 rpm.

[0037] Preferably, the shearing uniformity in step 3 is performed under the action of high-speed shearing force using a high-speed shearing homogenizer.

[0038] The rotation speed of the high-speed shearing homogenizer is 10,000-10,500 rpm, and the shearing time is 10-20 minutes.

[0039] Preferably, the stirring speed in step 4 is 400-500 rpm, and the stirring time is 2-3 minutes.

[0040] In the present application, high-speed stirring is required in step 3 to uniformly stir the water-oil phase, and only the ammonium persulfate needs to be uniformly distributed in step 4.

[0041] Preferably, the temperature for solidification and crosslinking in step 4 is 70-80℃, and the solidification and crosslinking time is 2.5-3 h; the container for solidification and crosslinking is a vacuum oven.

[0042] The present application simplifies the difficulty of synthesizing MXene / CNF / AAm organic hydrogel by using one-step thermal polymerization method. The nano-clay plays an important role in the technical scheme of the present application. On the one hand, it acts as a Pickering emulsifier, adsorbing on the oil-water interface to prevent oil droplet aggregation. On the other hand, it acts as a multifunctional crosslinking agent in the aqueous phase, effectively inhibiting oil droplet coalescence and keeping the emulsion morphology stable. The continuous aqueous network wraps and separates individual paraffin droplets, thereby uniformly distributing paraffin microsphere domains in the entire material. Therefore, these microsphere domains can serve as micro-inclusions of the organic gel, providing good shape memory properties and excellent thermal mechanical properties.

[0043] Another object of the present application is to provide an application of the shape memory organic hydrogel with heterogeneous phase change in the field of electromagnetic shielding.

[0044] In the technical scheme of the present application, when electromagnetic waves are incident on the hydrogel, the non-conductive paraffin adjusts the appropriate electrical conductivity to cause impedance matching, and most of the electromagnetic waves enter the interior of the organic hydrogel material; the presence of the two-dimensional material Mxene and the nano-clay forms a conductive network, and the conduction loss of the two-dimensional material Mxene and the nano-clay promotes the absorption of electromagnetic waves. In addition, the charge carriers generate micro-currents, resulting in ohmic loss and energy dissipation of electromagnetic waves. At the same time, the paraffin shell layer, the two-dimensional material Mxene and the nano-clay water phase form a honeycomb network structure for multiple reflection and scattering of electromagnetic waves; a large number of polar water molecules exist in the organic hydrogel material, and have a dipole moment, which forms a dipole polarization under the action of electromagnetic waves, further attenuating the electromagnetic wave energy; on the other hand, a large number of free charges are accumulated at the heterojunction interface between the aqueous solution and the oil solution, and these free charges can act as scattering sites, resulting in interface polarization loss; when the temperature rises, the paraffin changes from a solid state to a liquid state, and becomes an ellipsoid under the action of tensile stress, the specific surface area increases, and electromagnetic waves form scattering domains inside, increasing the propagation path of the waves and promoting greater dissipation of electromagnetic wave energy.

[0045] The MXene / CNF / AAm organic hydrogel prepared by the present application not only has excellent tensile properties, excellent thermal mechanical properties and shape memory effect, good environmental stability, but also can realize large-scale application. At the same time, the heterogeneous phase change organic hydrogel prepared by the present application exhibits a high strain capacity of rapid recovery in the shape memory process. Due to the medium conductivity of the two-dimensional material MXene network and the stable water-oil heterogeneous interface state and the rich water environment inside, the organic hydrogel exhibits an absorption-based electromagnetic shielding behavior. In addition, due to the phase change effect of the liquid paraffin, the organic hydrogel with the optimal water-oil ratio has excellent shape memory function and good repeatability stability.

[0046] The MXene / CNF / AAm organic hydrogel prepared by the present application exhibits efficient electromagnetic interference shielding performance mainly by absorption by optimizing the proportion of the aqueous phase and the oil phase in the organic hydrogel. The electromagnetic shielding performance can be adjusted at different temperatures. A simple and stable two-phase organic hydrogel is displayed, which has better comprehensive performance than most existing electromagnetic shielding hydrogel composite materials, and provides a reference for exploring more excellent electromagnetic shielding composite materials.

[0047] Compared with the prior art, the present application has at least the following beneficial effects:

[0048] (1) The organic hydrogel of the present application optimizes its mechanical properties by precisely regulating the proportion of the aqueous phase and the oil phase; has excellent electromagnetic shielding efficiency mainly by absorption and controllable electromagnetic shielding performance;

[0049] (2) The preparation method of the organic hydrogel prepared by the application is high-efficiency and stable, the process is simple and feasible, the synthesis condition of the organic hydrogel is 70 DEG C thermal polymerization, which reduces the difficulty of material synthesis and improves the synthesis efficiency of the material;

[0050] (3) The organic hydrogel prepared by the application has excellent tensile property, excellent thermal mechanical property and shape memory effect, and good environmental stability, and can be applied on a large scale;

[0051] (4) The organic hydrogel prepared by the application has a high strain capacity of rapid recovery in the shape memory process. BRIEF DESCRIPTION OF DRAWINGS

[0052] The accompanying drawings are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application.

[0053] Figure 1 The preparation flowchart of the MXene / CNF / AAm organic hydrogel prepared in embodiment 1 of the application;

[0054] Figure 2 The schematic diagram of the actual picture of the MXene / CNF / AAm organic hydrogel prepared in embodiments 1-4 of the application with different water-oil ratios;

[0055] Figure 3 (a) The schematic diagram of the scanning confocal microscope (CLSM) of the MXene / CNF / AAm organic hydrogel prepared in embodiments 1-4 of the application; (b) The schematic diagram of the scanning confocal microscope (CLSM) of the MXene / CNF / AAm organic hydrogel prepared in embodiments 1-4 of the application;

[0056] Figure 4 (a) The schematic diagram of the scanning electron microscope (SEM) of the MXene / CNF / AAm organic hydrogel prepared in embodiments 1-4 of the application; (b) The schematic diagram of the element mapping (EDS) of the MXene / CNF / AAm organic hydrogel prepared in embodiments 1-4 of the application;

[0057] Figure 5 (a) The schematic diagram of the stress-strain curve of the MXene / CNF / AAm organic hydrogel prepared in embodiments 1-4 of the application with different water-oil ratios at 25 DEG C; (b) The schematic diagram of the stress-strain curve of the MXene / CNF / AAm organic hydrogel prepared in embodiments 1-4 of the application with different water-oil ratios at 70 DEG C;

[0058] Figure 6(a) is a schematic diagram of the 200%-1000% stretch cycle curve of the organic hydrogel prepared in Examples 1-4 of the present application at different temperatures (70℃, 25℃); (b) is a schematic diagram of the stretch cycle curve of the organic hydrogel prepared in Examples 1-4 of the present application at different stretch times;

[0059] Figure 7 (a) is a schematic diagram of the 200%-1000% stretch cycle curve of the organic hydrogel prepared in Examples 1-4 of the present application at different temperatures (70℃, 25℃); (b) is a schematic diagram of the stretch cycle curve of the organic hydrogel prepared in Examples 1-4 of the present application at different stretch times;

[0060] Figure 8 (a) is a schematic diagram of the 200%-1000% stretch cycle curve of the organic hydrogel prepared in Examples 1-4 of the present application at different temperatures (70℃, 25℃); (b) is a schematic diagram of the stretch cycle curve of the organic hydrogel prepared in Examples 1-4 of the present application at different stretch times;

[0061] Figure 9 (a) is a schematic diagram of the 200%-1000% stretch cycle curve of the organic hydrogel prepared in Examples 1-4 of the present application at different temperatures (70℃, 25℃); (b) is a schematic diagram of the stretch cycle curve of the organic hydrogel prepared in Examples 1-4 of the present application at different stretch times; DETAILED DESCRIPTION

[0062] In order to more clearly understand the above-mentioned purposes, features and advantages of the present application, the present application will be further described in detail below in combination with the drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict. In addition, the present application can also be implemented in other ways different from those described herein, and therefore, the protection scope of the present application is not limited by the specific embodiments disclosed below.

[0063] One specific embodiment of the present application, as Figures 1-9 , discloses a preparation method of shape memory organic hydrogel with heterogeneous phase change and its application.

[0064] In order to illustrate the effectiveness of the method proposed in the present application, the above technical solutions of the present application will be described in detail below through a specific embodiment, and the specific implementation steps are as follows:

[0065] One purpose of the present application is to provide a shape memory organic hydrogel with heterogeneous phase change, which comprises acrylamide, two-dimensional material MXene, nanoclay and lauryl methacrylate and paraffin with a component content ratio of 3-9:0.1-0.3:0.8-2.4:4.5-9:7.5-10.5; the electromagnetic wave absorption rate of the organic hydrogel is 80%; the temperature of electromagnetic wave absorption is 70℃; the frequency range of electromagnetic wave is 12.4-18GHZ;

[0066] The organic hydrogel exhibits good electromagnetic shielding performance in the Ku band and exhibits absorption-dominated electromagnetic shielding properties at 70°C.

[0067] Preferably, the organohydrogel completely recovers to its original shape within 25 seconds at 70°C.

[0068] The organic hydrogel prepared by the present invention has good shape memory function to cope with complex real-world environments, can completely recover to its original shape within 25 seconds at 70°C, and has rapid shape memory response capability.

[0069] Another object of the present invention is to provide a method for preparing a shape memory organohydrogel with heterogeneous phase transition, comprising:

[0070] Step 1: Mix two-dimensional material MXene, acrylamide and nanoclay, then add surfactant and cross-linking agent 1 to obtain an aqueous solution;

[0071] Preferably, the specific steps of obtaining the aqueous phase solution in step 1 include:

[0072] Add acrylamide (AAm) and nanoclay to the aqueous solution of the two-dimensional material MXene, stir, and continue to add surfactant and cross-linking agent 1 to obtain an aqueous phase solution;

[0073] Step 2: Melting paraffin wax and adding lauryl methacrylate and a second crosslinking agent to obtain an oil phase solution;

[0074] Step 3: adding the aqueous phase solution to the oil phase solution and shearing them evenly to obtain an oil-in-water emulsion;

[0075] Step 4: Add ammonium persulfate and an initiator to the oil-in-water emulsion, stir, and perform curing and cross-linking to obtain a shape memory organic hydrogel with heterogeneous phase transition.

[0076] Preferably, the two-dimensional material MXene in step 1 is a metal carbide or metal nitride material having a two-dimensional layered structure;

[0077] The volume of the two-dimensional material MXene aqueous solution is 10-30 ml, with 10 mg per ml;

[0078] Preferably, the mass ratio of the acrylamide to the nanoclay in step 1 is 3-9:0.8-2.4;

[0079] Furthermore, the mass of the acrylamide is 3-9 g; the mass of the nanoclay is 0.8-2.4 g;

[0080] Furthermore, the nanoclay may be montmorillonite or halloysite;

[0081] Preferably, the stirring speed of step 1 is 500-800 rpm, the stirring time is 10-15 min, and the stirring temperature is 50-55℃;

[0082] Preferably, the surfactant of step 1 is sodium dodecyl sulfate (SDS);

[0083] Preferably, the crosslinking agent I of step 1 is N,N'-methylene bisacrylamide (MBA);

[0084] Preferably, the melting temperature of step 2 is 50-55℃;

[0085] Preferably, the crosslinking agent II of step 2 is ethylene glycol dimethacrylate;

[0086] Preferably, the mass ratio of paraffin, lauryl methacrylate and crosslinking agent II of step 2 is 7.5-10.5:4.5-9:0.13;

[0087] Preferably, the molar mass ratio of the crosslinking agent I to the crosslinking agent II is 20:13;

[0088] Further, the mass of the paraffin is 7.5-10.5 g; the mass of the lauryl methacrylate LMA is 4.5-9 g;

[0089] Preferably, the mass ratio of ammonium persulfate (APS) to initiator is 3:10;

[0090] Further, the mass of the ammonium persulfate (APS) is 15-20 mg;

[0091] The initiator is 2,2-azobisisobutyronitrile (AIBN) (EGDMA);

[0092] Preferably, the stirring speed of step 2 is 500-800 rpm;

[0093] Preferably, the shearing homogenization of step 3 is carried out using a high-speed shearing homogenizer under the action of high-speed shearing force;

[0094] The rotation speed of the high-speed shearing homogenizer is 10,000-10,500 rpm, and the shearing time is 10-20 min.

[0095] Preferably, the stirring speed of step 4 is 400-500 rpm, and the stirring time is 2-3 min;

[0096] In the present application, high-speed stirring is required in step 3 to uniformly stir the water-oil phase, and only ammonium persulfate needs to be uniformly distributed in step 4.

[0097] Preferably, the temperature of the curing cross-linking in step 4 is 70-80℃, and the curing cross-linking time is 2.5-3h; the curing cross-linking container is a vacuum oven.

[0098] Example one

[0099] Step 1, take 15ml of two-dimensional material MXene aqueous solution (10mg mL -1 ) into a beaker with a capacity of 40ml, then add 4.5g of acrylamide and 12g of nanoclay, stir at a magnetic stirring speed of 500rpm to obtain a uniform aqueous phase, then add 200mg of N,N'-methylene bisacrylamide as a crosslinking agent and 1ml of sodium dodecyl sulfate as a surfactant to obtain an aqueous phase solution;

[0100] Step 2, take 10.5g of paraffin into a beaker with a capacity of 50ml, heat to 55℃, and after the above paraffin is completely melted into a liquid, add 4.5g of lauryl methacrylate and 0.13g of ethylene glycol dimethacrylate as a lipophilic crosslinking agent, stir at a magnetic stirring speed of 800rpm for 10 minutes to obtain an oil phase solution;

[0101] Step 3, mix the prepared aqueous phase solution with the oil phase solution, and use a high-speed shearing homogenizer to shear at 10000rpm at 55℃ for 5 minutes, then add 0.03g of ammonium persulfate and 0.1g of 2,2-azobis isobutyronitrile as a thermal initiator to the mixed solution, stir at 600rpm for 3 minutes, then pour into a polytetrafluoroethylene mold, and place it in a vacuum oven at 70℃ for cross-linking polymerization for 2.5h to obtain MXene / CNF / AAm organic hydrogel, which is placed in a vacuum glove box for subsequent testing as sample one.

[0102] Example two

[0103] Change the content of two-dimensional material MXene aqueous solution in step one of example one to 20ml, change the content of paraffin in step 2 to 7g, and the rest remains unchanged to obtain sample two V H :V O =2:1.

[0104] Example three

[0105] Change the content of two-dimensional material MXene aqueous solution in step one of example one to 12ml, change the content of paraffin in step 2 to 12.6g, and the rest remains unchanged to obtain sample two V H :V O =2:3.

[0106] Example four

[0107] The content of the two-dimensional material MXene aqueous solution in step 1 of Example 1 was changed to 10 ml, the content of paraffin in step 2 was changed to 14 g, and the rest remained unchanged to obtain sample 3 V. H :V O =2:4.

[0108] like Figure 2 As shown in the figures, the actual photos of samples 1, 2, 3 and 4 prepared in Examples 1-4 at different water-oil ratios show that their surfaces are smooth and flat, and they are all round hydrogel sheets with a diameter of 40.0 mm and a thickness of 1.5 mm.

[0109] like Figures 3-4 As shown, the morphologies of Samples 1, 2, 3, and 4 prepared in Examples 1-4 under scanning confocal microscopy and scanning electron microscopy clearly reveal the internal microstructure of the hydrogel, showing that the organic hydrogel forms a continuous network. The scanning electron microscopy images reveal that the oily paraffin wax is tightly encapsulated within the continuous hydrogel network, with the resulting paraffin wax microspheres having an average particle size of approximately 20.63 μm. The corresponding energy dispersive X-ray spectroscopy (EDX-ray spectroscopy) spectra show that the two-dimensional MXene material is uniformly distributed throughout the hydrogel network.

[0110] like Figures 5-6 As shown in FIG, the tensile properties of samples 1, 2, 3 and 4 prepared in Examples 1 to 4 at different ambient temperatures indicate that they have good tensile capacity at different ambient temperatures, ensuring their durability and stability.

[0111] like Figure 7 As shown, samples 1, 2, 3 and 4 prepared in Examples 1-4 have shape programming and shape memory functions at 70°C, indicating their excellent shape recovery ability and good recyclability, ensuring the practicality of the composite organic hydrogel.

[0112] Example 5

[0113] Samples 1, 2, 3 and 4 prepared in Examples 1-4 were applied to Ku-band electromagnetic shielding performance testing.

[0114] A vector network analyzer was used to evaluate the electromagnetic shielding performance of samples 1, 2, 3 and 4 prepared in Examples 1-4. The sample size was 5*5 cm square sample with a thickness of 1 mm. The electromagnetic wave frequency range used in the test was 12.4 to 18 GHz.

[0115] like Figure 8 As shown, the electromagnetic shielding efficiency (SE) of samples 1, 2, 3 and 4 prepared in Examples 1-4 under different water-oil ratios is shown. T ) and power coefficient; From the data in the figure, we can see that V H :V O= 2:1, V H : V O = 2:2, V H : V O = 2:3, and V H : V O = 2:4 SE T values of 48.84, 58.06, 46.61 and 40.02 dB, all of which are superior to the 20 dB target value of the commercial electromagnetic shielding material, and the absorption rates at 70℃ are all higher than the reflection rates, V H : V O = 2:2 absorption rate reaches the optimal value, indicating that the organic hydrogel of the present application is an electromagnetic shielding material mainly by absorption.

[0116] Example Six

[0117] The samples one, two, three and four prepared in Examples One-Four were applied to the electromagnetic shielding performance stability test.

[0118] As Figure Seven shown, the electromagnetic shielding performance of the samples one, two, three and four prepared in Examples One-Four after storage at 25℃ and 70℃ for different days, from the data graph, it can be obtained that the average SE T value at 70℃ after 7 days is stable at 40.38 dB, still able to meet the requirements of commercial applications, indicating that the samples one, two, three and four prepared in Examples One-Four have good environmental stability.

[0119] The above description is only the preferred specific implementation of the present application, but the protection scope of the present application is not limited to this, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A method for preparing a shape memory organohydrogel with heterogeneous phase transition, characterized in that: include: Step 1: Mix the two-dimensional material MXene, acrylamide and nanoclay, and then add a surfactant and a cross-linking agent to obtain an aqueous solution; Step 2: Melting paraffin wax and adding lauryl methacrylate and a second crosslinking agent to obtain an oil phase solution; Step 3: adding the aqueous phase solution to the oil phase solution and shearing them evenly to obtain an oil-in-water emulsion; Step 4: Add ammonium persulfate and an initiator to the oil-in-water emulsion, stir, and perform curing and cross-linking to obtain a shape memory organic hydrogel with heterogeneous phase transition.

2. The method for preparing the shape memory organohydrogel with heterogeneous phase transition according to claim 1, characterized in that: The mass ratio of the acrylamide to the nanoclay in step 1 is 3-9:0.8-2.

4.

3. The method for preparing the shape memory organohydrogel with heterogeneous phase transition according to claim 1, characterized in that: The mass ratio of the paraffin wax, lauryl methacrylate and cross-linking agent 2 in step 2 is 7.5-10.5:4.5-9:0.

13.

4. The method for preparing a shape memory organohydrogel with heterogeneous phase transition according to claim 1, characterized in that: The mass ratio of the cross-linking agent 1 to the cross-linking agent 2 is 20:

13.

5. The method for preparing the shape memory organohydrogel with heterogeneous phase transition according to claim 1, characterized in that: The mass ratio of the ammonium persulfate to the initiator is 3:

10.

6. The method for preparing the shape memory organohydrogel with heterogeneous phase transition according to claim 1, characterized in that: The uniform shearing in step 3 is performed by using a high-speed shear homogenizer under the action of a high-speed shear force.

7. The method for preparing the shape memory organohydrogel with heterogeneous phase transition according to claim 6, characterized in that: The rotation speed of the high-speed shear homogenizer is 10000-10500 rpm, and the shearing time is 10-20 minutes.

8. The method for preparing a shape memory organohydrogel with heterogeneous phase transition according to claim 1, characterized in that: The curing and cross-linking temperature in step 4 is 70-80° C., and the curing and cross-linking time is 2.5-3 hours.

9. A shape memory organohydrogel with heterogeneous phase transition, prepared according to the preparation method according to any one of claims 1 to 8, characterized in that: The shape memory organic hydrogel with heterogeneous phase transition includes acrylamide, two-dimensional material MXene, nanoclay, lauryl methacrylate and paraffin.

10. Application of a shape memory organohydrogel with heterogeneous phase transition, characterized in that: The shape memory organohydrogel according to claim 9 is used for electromagnetic shielding.

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