Preparation method of natural rubber filled nickel-aluminum bimetallic hydroxide multi-walled carbon nanotube composite for electronic component packaging

Abstract

The application discloses a kind of natural rubber filling nickel-aluminum bimetallic hydroxide multi-walled carbon nanotube composite material for electronic component packaging, belong to packaging material technical field, the composite material includes natural rubber matrix and dispersed nickel-aluminum bimetallic hydroxide / multi-walled carbon nanotube hybrid filler, the hybrid filler is made of multi-walled carbon nanotube and nickel-aluminum layered double hydroxide grown in its surface in situ.Its preparation method is: multi-walled carbon nanotube, nickel source, aluminum source, urea and ammonium fluoride are dissolved in water and prepared hybrid filler by hydrothermal reaction;Then it is mixed with natural latex, vulcanization aid dispersion, freeze-drying, vulcanization is obtained.The application improves the dispersibility of filler by constructing LDH / MWCNT hybrid structure, uses phonon transmission optimization, synergism of loss and impedance, combustion inhibition and the friction and reinforcing mechanism of hybrid filler and natural rubber molecular chain, so that the thermal conductivity, electromagnetic wave absorption capacity, flame retardancy, mechanics and damping performance of the composite material are simultaneously improved, suitable for electronic component packaging field.

Description

Technical Field

[0001] This invention belongs to the field of packaging materials technology, and particularly relates to a method for preparing a natural rubber-filled nickel-aluminum bimetallic hydroxide multi-walled carbon nanotube composite material for electronic component packaging. Background Technology

[0002] Encapsulation materials are core functional materials that fill the contact gaps between electronic components and heat dissipation structures, reducing interfacial thermal resistance. Their comprehensive performance directly determines the operational reliability and lifespan of electronic devices. Traditional electronic encapsulation materials are mostly based on epoxy resin and silicone, with the core function of protecting electronic devices from damage caused by external environmental factors such as dust, moisture, chemical corrosion, and physical impact. These materials mainly rely on adding a large amount of thermally conductive inorganic fillers to build a phonon transmission network, enabling the rapid dissipation of heat accumulated during the operation of electronic devices.

[0003] In recent years, the fields of automotive devices, marine equipment, and military weapons have developed rapidly, and the operating conditions of electronic devices have become increasingly complex and demanding. The performance requirements for packaging materials have been upgraded from simply high thermal conductivity to a multi-functional combination of thermal conductivity, electromagnetic protection, vibration damping, and flame retardancy. Developing new packaging materials that combine the above comprehensive properties has become an urgent need for the industry.

[0004] Natural rubber (NR), as a renewable natural polymer material that does not rely on fossil fuels, has shown great potential in the application of damping encapsulation materials due to its excellent mechanical properties and high elasticity and vibration damping characteristics. Multi-walled carbon nanotubes (MWCNTs), due to their good compatibility with natural rubber and their characteristics of low density, high thermal conductivity, and strong electrical conductivity, can effectively improve the thermal conductivity and electromagnetic interference resistance of natural rubber matrices. However, the inherent characteristics of carbon nanotubes limit their application in electromagnetic wave absorption and thermal management: on the one hand, the loss mechanism of carbon materials is simple and the impedance matching is poor, resulting in low electromagnetic wave absorption efficiency; on the other hand, carbon nanotubes are prone to agglomeration in natural rubber matrices, resulting in poor dispersion and making it difficult to fully utilize their high thermal conductivity advantage, thus limiting the significant improvement of the thermal conductivity of natural rubber-based encapsulation materials.

[0005] Against this backdrop, there is an urgent need to develop effective strategies to construct and optimize the composition and structure of carbon nanotubes in order to improve the thermal conductivity and electromagnetic wave absorption performance of natural rubber-based encapsulation materials. At the same time, flame retardancy, as a fundamental property of encapsulation materials, also needs to be further improved. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention proposes a method for preparing a natural rubber-filled nickel-aluminum bimetallic hydroxide multi-walled carbon nanotube composite material for electronic component packaging.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A natural rubber-filled nickel-aluminum bimetallic hydroxide / multi-walled carbon nanotube composite material, comprising: a natural rubber matrix, and a nickel-aluminum bimetallic hydroxide / multi-walled carbon nanotube hybrid filler dispersed in the natural rubber matrix; The nickel-aluminum layered bimetallic hydroxide in the nickel-aluminum bimetallic hydroxide / multi-walled carbon nanotube hybrid filler is grown in situ on the surface of multi-walled carbon nanotubes.

[0008] Two-dimensional nickel-aluminum layered bimetallic hydroxides (LDHs) possess stable endothermic properties and release water molecules and carbon dioxide during combustion to achieve flame retardancy. Furthermore, LDHs can be grown in situ on the surface of carbon nanotubes via hydrothermal reactions, effectively enhancing the interfacial polarization mechanism of inorganic composite materials, optimizing impedance matching effects, and modulating the phonon transport network structure. This, in turn, simultaneously improves the overall thermal conductivity, electromagnetic wave absorption, and flame retardancy of natural rubber-based encapsulation materials. This invention overcomes the shortcomings of single carbon nanotubes, such as easy aggregation and a single loss mechanism, by constructing a hybrid structure of LDH grown in situ on the surface of MWCNTs. This structure enhances the interfacial bonding between the filler and the rubber matrix, laying a structural foundation for subsequent improvements in thermal conductivity, electromagnetic absorption, flame retardancy, and mechanical properties.

[0009] This invention also provides a method for preparing a natural rubber-filled nickel-aluminum bimetallic hydroxide multi-walled carbon nanotube composite material, comprising the following steps: Multi-walled carbon nanotubes, nickel source, aluminum source, urea and ammonium fluoride were dissolved in deionized water, and the mixture was homogenized by ultrasonication and stirring. The mixture was then subjected to hydrothermal reaction to obtain nickel-aluminum bimetallic hydroxide / multi-walled carbon nanotube hybrid filler. The nickel-aluminum bimetallic hydroxide / multi-walled carbon nanotube hybrid filler is mixed with natural latex and vulcanizing aid dispersion, and then vulcanized after stirring, freeze drying, thin-passing, and standing to obtain a natural rubber-filled nickel-aluminum bimetallic hydroxide multi-walled carbon nanotube composite material.

[0010] This preparation method is simple and operates under mild conditions. It achieves in-situ growth of LDH on the surface of MWCNTs via a hydrothermal method, followed by uniform dispersion of the filler in natural rubber through latex blending, making it suitable for industrial production. Freeze-drying and thin-pass processing further improve the filler distribution, ensuring the comprehensive performance of the composite material.

[0011] Furthermore, the ratio of the amount of multi-walled carbon nanotubes, nickel source, aluminum source, urea, ammonium fluoride and deionized water is 0.6g:(0.435-1.305)g:(0.19-0.57)g:(1.2-3.6)g:(0.28-0.83)g:350mL.

[0012] This invention optimizes the raw material ratio to control the growth density and morphology of LDH on the MWCNT surface. This ratio range can achieve the best balance between hybrid structure and performance.

[0013] Furthermore, the nickel source is selected from Ni(NO3)2·6H2O; the aluminum source is selected from Al(NO3)3·9H2O.

[0014] This invention selects nitrates as nickel and aluminum sources, which have good solubility and high reactivity, and are conducive to the formation of LDH sheets with high crystallinity and uniform morphology in hydrothermal reaction, thus ensuring the quality stability of the hybrid filler.

[0015] Furthermore, the stirring speed is 500 rpm and the stirring time is 30 min. The hydrothermal reaction temperature is 120°C, and the hydrothermal reaction time is 8 hours.

[0016] These process parameters ensure thorough mixing of the reactants and uniform nucleation and growth of LDH. The hydrothermal conditions of 120℃ / 8h enable the formation of a dense and firmly bonded LDH layer on the MWCNT surface, preventing overgrowth or shedding.

[0017] Furthermore, the mass ratio of the nickel-aluminum bimetallic hydroxide / multi-walled carbon nanotube hybrid filler, natural latex, and vulcanizing aid dispersion is 1.34:25:5.18.

[0018] This formulation achieves an appropriate amount of filler in the rubber matrix, ensuring improved functionality (thermal conductivity, electromagnetic absorption) without compromising the processability and mechanical properties of the rubber.

[0019] Furthermore, the dry rubber content of the natural latex is 40 wt%.

[0020] A dry rubber content of 40 wt% is a typical concentration for natural latex, which facilitates uniform mixing with fillers and additives and maintains structural stability during freeze-drying, preventing filler migration or agglomeration.

[0021] Furthermore, the vulcanizing aid dispersion is obtained by mixing stearic acid, zinc oxide, sulfur, vulcanization accelerator, dispersant, casein and antioxidant in a mass ratio of 20:50:20:10:3:4:100; the solid content of the vulcanizing aid dispersion is 40wt%.

[0022] This vulcanization system has a mature formulation that is well-matched with natural rubber, ensuring the uniform formation of the vulcanization crosslinking network. The addition of dispersants and casein helps the fillers disperse in the latex, while antioxidants improve the service life of the composite material.

[0023] Furthermore, the vulcanization temperature is 120°C, and the vulcanization time is 25 minutes.

[0024] The vulcanization conditions of 120℃ / 25min are within the normal vulcanization time range for natural rubber, which can form a moderate crosslinking density, ensuring the mechanical strength of the composite material while avoiding performance degradation caused by over-vulcanization.

[0025] This invention also provides an application of a natural rubber-filled nickel-aluminum bimetallic hydroxide multi-walled carbon nanotube composite material in the field of electronic component packaging.

[0026] This composite material combines high thermal conductivity (rapid heat dissipation), excellent electromagnetic wave absorption (interference resistance), good damping (vibration reduction), and flame retardancy (safety protection) properties, which can meet the needs of electronic component packaging for multifunctional materials, and is especially suitable for complex and harsh environments such as automotive, marine, and military applications.

[0027] Compared with the prior art, the present invention has the following advantages and technical effects: This invention utilizes a hydrothermal method to in-situ grow a nickel-aluminum layered bimetallic hydroxide on the surface of carbon nanotubes, constructing a hybrid filler with a heterogeneous interface. Introducing this filler into a natural rubber matrix not only significantly improves the dispersion of carbon nanotubes but also simultaneously enhances the composite material's thermal conductivity (up to 0.29 W / (m·K)), electromagnetic wave absorption capacity (reflection loss as low as -48.10 dB), flame retardancy (significantly reduced total heat release), and mechanical and damping properties through interfacial polarization, optimized phonon transport, and combustion suppression mechanisms. This composite material exhibits excellent multifunctional application potential in the field of electronic component packaging. Attached Figure Description

[0028] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 Transmission electron microscope (TEM) images of the natural rubber composite materials prepared in Example 1 and Comparative Example 1; Figure 2 The XRD diffraction patterns of the fillers prepared in Examples 1-3 and Comparative Examples 1-2 are shown below. Figure 3 XPS diffraction patterns of the fillers prepared in Examples 1-3 and Comparative Examples 1-2; Figure 4 The electromagnetic wave absorption performance diagrams of the composite materials prepared in Examples 1-3 are shown. Figure 5 Thermal conductivity diagrams of the composite materials prepared in Examples 1-3, Comparative Examples 1-2, and natural rubber are shown. Figure 6The tensile strength diagrams are of the composite materials prepared in Examples 1-3 and Comparative Examples 1-2, and of natural rubber. Figure 7 The damping coefficient diagrams are shown for the composite materials prepared in Examples 1-3 and Comparative Examples 1-2, as well as for natural rubber. Figure 8 The total heat release diagram of the composite material prepared in Example 1; Figure 9 The graphs show the heat release peak values ​​of the composite materials prepared in Examples 1-3 and Comparative Examples 1-2. Detailed Implementation

[0029] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0030] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0031] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0032] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0033] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0034] This invention provides a natural rubber-filled nickel-aluminum bimetallic hydroxide multi-walled carbon nanotube composite material, comprising: a natural rubber matrix, and a nickel-aluminum bimetallic hydroxide / multi-walled carbon nanotube hybrid filler dispersed in the natural rubber matrix; the hybrid filler is composed of multi-walled carbon nanotubes and nickel-aluminum layered bimetallic hydroxide grown in situ on its surface.

[0035] The preparation method of this natural rubber-filled nickel-aluminum bimetallic hydroxide multi-walled carbon nanotube composite material includes the following steps: (1) Multi-walled carbon nanotubes (MWCNTs), nickel source (Ni(NO3)2·6H2O), aluminum source (Al(NO3)3·9H2O), urea (H2NCONH2) and ammonium fluoride (NH4F) were dissolved in deionized water. The solution was mixed evenly by ultrasonic and magnetic stirring (stirring rate of 500 r / min, time of 30 min). The mixed solution was transferred to a high-pressure reactor and reacted at 120℃ for 8 h to obtain nickel-aluminum bimetallic hydroxide / multi-walled carbon nanotube hybrid filler. The ratio of multi-walled carbon nanotubes, nickel source, aluminum source, urea, ammonium fluoride, and deionized water is 0.6g:(0.435-1.305)g:(0.19-0.57)g:(1.2-3.6)g:(0.28-0.83)g:350mL. For example, in the following preferred embodiments of the present invention, the ratio of multi-walled carbon nanotubes, nickel source, aluminum source, urea, ammonium fluoride, and deionized water is 0.6g:0.435g:0.19g:1.2g:0.28g:350mL, 0.6g:0.87g:0.38g:2.4g:0.56g:350mL, or 0.6g:1.305g:0.57g:3.6g:0.83g:350mL. (2) The nickel-aluminum bimetallic hydroxide / multi-walled carbon nanotube hybrid filler prepared in step (1) is mixed with natural latex (dry rubber content of 40wt%) and vulcanizing aid dispersion (solid content of 40wt%). The mixture is magnetically stirred for 30 min at a stirring rate of 500 rpm, freeze-dried, passed through a thin tube 6 times and left to stand for 12 h before vulcanization. The vulcanization temperature is 120℃ and the vulcanization time is 25 min to obtain natural rubber filled nickel-aluminum bimetallic hydroxide multi-walled carbon nanotube composite material. The mass ratio of the nickel-aluminum bimetallic hydroxide / multi-walled carbon nanotube hybrid filler, natural latex, and vulcanizing aid dispersion is 1.34:25:5.18. The vulcanization aid dispersion is obtained by mixing stearic acid, zinc oxide, sulfur, vulcanization accelerator (N-cyclohexyl-2-benzothiazole sulfenamide), dispersant (sodium methylene dinaphthalene sulfonate), casein, and antioxidant (4010NA) in a mass ratio of 20:50:20:10:3:4:100.

[0036] This natural rubber-filled nickel-aluminum bimetallic hydroxide multi-walled carbon nanotube composite material can be used in the field of electronic component packaging.

[0037] Unless otherwise specified, "room temperature" in this invention refers to 25±2℃.

[0038] All raw materials used in the following embodiments of the present invention were purchased from the market. Specifically: multi-walled carbon nanotubes were purchased from Xianfeng Nanomaterials Technology Co., Ltd.; Ni(NO3)2·6H2O and Al(NO3)3·9H2O were purchased from Aladdin Reagent Co., Ltd.; urea and ammonium fluoride were purchased from Maclean Biochemical Technology Co., Ltd.; natural latex was provided by the Danzhou Base of the Rubber Research Institute of the Chinese Academy of Tropical Agricultural Sciences; and all vulcanization aid precursors were purchased from Aladdin Reagent Co., Ltd. and were milled with water to obtain dispersions.

[0039] The technical solution of the present invention will be further illustrated by the following embodiments.

[0040] Examples 1-3, Comparative Examples 1-2 A method for preparing a natural rubber-filled nickel-aluminum bimetallic hydroxide multi-walled carbon nanotube composite material includes the following steps: (1) According to the amount of raw materials in Table 1, multi-walled carbon nanotubes (MWCNT), nickel source (Ni(NO3)2·6H2O), aluminum source (Al(NO3)3·9H2O), urea (H2NCONH2) and ammonium fluoride (NH4F) were dissolved in deionized water. The solution was mixed evenly by ultrasonic and magnetic stirring (stirring rate of 500 r / min, time of 30 min). The mixed solution was transferred to a high-pressure reactor and reacted at 120℃ for 8 h to obtain nickel-aluminum bimetallic hydroxide / multi-walled carbon nanotube hybrid filler. (2) Mix 1.34g of the nickel-aluminum bimetallic hydroxide / multi-walled carbon nanotube hybrid filler prepared in step (1), 25g of natural latex (NR, dry rubber content of 40wt%), and 5.18g of vulcanizing aid dispersion (solid content of 40wt%, obtained by mixing stearic acid, zinc oxide, sulfur, N-cyclohexyl-2-benzothiazole sulfenamide, sodium methylene dinaphthalene sulfonate, casein and antioxidant (4010NA) in a mass ratio of 20:50:20:10:3:4:100) and stir magnetically for 30 minutes. The mixture was stirred at 500 rpm for 1 minute, then rapidly frozen with liquid nitrogen to remove moisture. After passing through a two-roll mill 6 times and standing for 12 hours, it was vulcanized at 120°C for 25 minutes to obtain natural rubber-filled nickel-aluminum bimetallic hydroxide multi-walled carbon nanotube composite materials (named MWCNT / NR, LDH / MWCNT-1 / NR, LDH / MWCNT-2 / NR, LDH / MWCNT-3 / NR and LDH / NR, respectively).

[0041] Table 1 shows the amount of each raw material used in step (1). Performance testing: 1. Morphology: The microstructure of the samples was characterized using a high-resolution electron microscope (HRTEM, JEM-2100).

[0042] 2. Crystal structure: X-ray diffractometer (Bruker D8 ADVANCE) was used to record the curves of the prepared inorganic filler in the range of 2θ from 5 to 80°, which were used to analyze the crystal structure and phase composition.

[0043] 3. Surface elements: XPS data were measured using an X-ray photoelectron spectroscopy (ESCALAB 250Xi) excitation source of 532nm.

[0044] 4. Thermal conductivity: The thermal conductivity is calculated using κ = D·CP·ρ, where the thermal diffusivity (D) is determined by laser flash method (DLF-1 / EM1200, TA Inc.). Specific heat (Cp) is determined using differential scanning calorimetry (DSC25TA Inc.) in an Ar atmosphere, and density (ρ) is determined using the sample size and mass. A typical disc sample has a diameter of 15 mm and a density not less than 96% of the theoretical density.

[0045] 5. Electromagnetic parameters: The electromagnetic parameters of the samples were measured using an Agilent (N5244A) vector network analyzer, with a frequency range of 2-18 GHz. Before testing, the rubber samples were prepared into coaxial rings (outer diameter = 7.02 mm, inner diameter = 3.04 mm, thickness = 2 mm).

[0046] 6. Flame retardancy: The heat release curves of each sample were measured using a micro calorimeter (MCC-2, MWCNTvmark), and the total heat release was calculated by integration.

[0047] 7. Damping: Tested using a dynamic mechanical property spectrum analyzer (DMTS EPLEXOR 500N) manufactured by GABO GmbH, Germany. The vulcanized rubber sample size was 20mm × 4mm × 1mm. Tensile mode was used, the test temperature was room temperature, the frequency was 1Hz, the initial clamping distance was 3.7mm, and the strain range was 0.28-20%.

[0048] Test results: 1. Figure 1 The images show transmission electron microscopy (TEM) images of the natural rubber composites prepared in Example 1 and Comparative Example 1. The results in the images show that the dispersion of the natural rubber in Example 1 was significantly improved after LDH modification compared to Comparative Example 1.

[0049] 2. Figure 2 The XRD diffraction patterns of the fillers prepared in Examples 1-3 and Comparative Examples 1-2 are shown in the figures. It can be seen from the figures that typical LDH and MWCNT characteristic peaks appeared in Examples 1-3, proving that LDH was successfully loaded on the MWCNT surface and verifying the formation of the hybrid structure. Comparative Example 1 (pure MWCNT) and Comparative Example 2 (pure LDH) only have diffraction peaks of a single component.

[0050] 3. Figure 3 The XPS diffraction patterns of the fillers prepared in Examples 1-3 and Comparative Examples 1-2 are shown. XPS analysis further confirmed the chemical states of elements such as Ni, Al, C, and O in the LDH / MWCNT hybrid fillers, which exhibited surface elemental characteristics consistent with the composition.

[0051] 4. Figure 4 The figures show the electromagnetic wave absorption performance of the composite materials prepared in Examples 1-3. As can be seen from the figures, the introduction of LDH effectively modulates the electromagnetic parameters of the composite materials, enhances the interfacial polarization capability, and achieves a synergistic effect of impedance matching and attenuation capability. The reflection loss of MWCNT / NR at a thickness of 1.7 mm is -13.08 dB, with an effective absorption bandwidth of 2.00 GHz; the reflection loss of LDH / MWCNT-1 / NR at a thickness of 1.3 mm is -48.10 dB, with an effective absorption bandwidth of 4.00 GHz, which is the best value among all samples; the reflection loss of LDH / MWCNT-2 / NR at a thickness of 3.6 mm is -44.40 dB, with an effective absorption bandwidth of 1.68 GHz; the reflection loss of LDH / MWCNT-3 / NR at a thickness of 5.5 mm is -19.3 dB, with an effective absorption bandwidth of 2.24 GHz; the minimum reflection loss of LDH / NR is -1.00 dB, with no effective absorption bandwidth.

[0052] 5. Figure 5 The figures show the thermal conductivity of the composite materials prepared in Examples 1-3, Comparative Examples 1-2, and pure natural rubber. As can be seen from the figures, the thermal conductivity of MWCNT / NR, LDH / MWCNT-1 / NR, LDH / MWCNT-2 / NR, LDH / MWCNT-3 / NR, and LDH / NR are 0.30 W / (m·K), 0.29 W / (m·K), 0.25 W / (m·K), 0.24 W / (m·K), and 0.17 W / (m·K), respectively. The thermal conductivity of LDH / MWCNT-1 / NR is 81.25% higher than that of the NR sample and only 0.01 W / (m·K lower than that of MWCNT / NR. This is because LDH inhibits the aggregation of MWCNTs in the natural rubber matrix, resulting in a superior phonon transport network structure.

[0053] 6. Figure 6 The figures show the tensile strength of the composite materials prepared in Examples 1-3 and Comparative Examples 1-2, as well as natural rubber. It can be seen from the figures that among all samples, the LDH / MWCNT-1 / NR prepared in Example 1 has the best mechanical properties, which is also due to the fact that LDH inhibits the aggregation of MWCNT in the natural rubber matrix.

[0054] 7. Figure 7 The graph shows the damping coefficients of the composite materials prepared in Examples 1-3 and Comparative Examples 1-2, as well as natural rubber. It can be seen from the graph that among all samples, the LDH / MWCNT-1 / NR prepared in Example 1 has the best damping performance. LDH inhibits the aggregation of MWCNT in the natural rubber matrix and increases the friction with the natural rubber molecular chains, resulting in enhanced damping performance.

[0055] 8. Figure 8 The total heat release curve of the composite material prepared in Example 1 is shown. The heat release curve also shows that the LDH / MWCNT-1 / NR prepared in Example 1 is lower than that of pure natural rubber. This is because the H2O and CO2 generated by LDH when heated inhibit the combustion of natural rubber.

[0056] 9. Figure 9 The graphs show the heat release peak values ​​of the composite materials prepared in Examples 1-3 and Comparative Examples 1-2. As can be seen from the graphs, the heat release peak values ​​of Examples 1-3 are all lower than those of the comparative examples; this further confirms that the introduction of LDH significantly reduces the heat release rate of the composite materials and enhances the flame retardant effect. The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A natural rubber-filled nickel-aluminum bimetallic hydroxide multi-walled carbon nanotube composite material, characterized in that, include: A natural rubber matrix, and a nickel-aluminum bimetallic hydroxide / multi-walled carbon nanotube hybrid filler dispersed in the natural rubber matrix; The nickel-aluminum layered bimetallic hydroxide in the nickel-aluminum bimetallic hydroxide / multi-walled carbon nanotube hybrid filler is grown in situ on the surface of multi-walled carbon nanotubes.

2. A method for preparing the natural rubber-filled nickel-aluminum bimetallic hydroxide multi-walled carbon nanotube composite material as described in claim 1, characterized in that, Includes the following steps: Multi-walled carbon nanotubes, nickel source, aluminum source, urea and ammonium fluoride were dissolved in deionized water, and the mixture was homogenized by ultrasonication and stirring. The mixture was then subjected to hydrothermal reaction to obtain nickel-aluminum bimetallic hydroxide / multi-walled carbon nanotube hybrid filler. The nickel-aluminum bimetallic hydroxide / multi-walled carbon nanotube hybrid filler is mixed with natural latex and vulcanizing aid dispersion, and then vulcanized after stirring, freeze drying, thin-passing, and standing to obtain a natural rubber-filled nickel-aluminum bimetallic hydroxide multi-walled carbon nanotube composite material.

3. The method for preparing the natural rubber-filled nickel-aluminum bimetallic hydroxide multi-walled carbon nanotube composite material according to claim 2, characterized in that, The ratio of the amount of multi-walled carbon nanotubes, nickel source, aluminum source, urea, ammonium fluoride and deionized water is 0.6g:(0.435-1.305)g:(0.19-0.57)g:(1.2-3.6)g:(0.28-0.83)g:350mL.

4. The method for preparing the natural rubber-filled nickel-aluminum bimetallic hydroxide multi-walled carbon nanotube composite material according to claim 3, characterized in that, The nickel source is selected from Ni(NO3)2·6H2O; the aluminum source is selected from Al(NO3)3·9H2O.

5. The method for preparing the natural rubber-filled nickel-aluminum bimetallic hydroxide multi-walled carbon nanotube composite material according to claim 2, characterized in that, The stirring speed was 500 rpm and the stirring time was 30 min. The hydrothermal reaction temperature is 120°C, and the hydrothermal reaction time is 8 hours.

6. The method for preparing the natural rubber-filled nickel-aluminum bimetallic hydroxide multi-walled carbon nanotube composite material according to claim 2, characterized in that, The mass ratio of the nickel-aluminum bimetallic hydroxide / multi-walled carbon nanotube hybrid filler, natural latex, and vulcanizing aid dispersion is 1.34:25:5.

18.

7. The method for preparing the natural rubber-filled nickel-aluminum bimetallic hydroxide multi-walled carbon nanotube composite material according to claim 6, characterized in that, The dry rubber content of the natural latex is 40 wt%.

8. The method for preparing the natural rubber-filled nickel-aluminum bimetallic hydroxide multi-walled carbon nanotube composite material according to claim 6, characterized in that, The vulcanization aid dispersion is obtained by mixing stearic acid, zinc oxide, sulfur, vulcanization accelerator, dispersant, casein and antioxidant in a mass ratio of 20:50:20:10:3:4:100; the solid content of the vulcanization aid dispersion is 40wt%.

9. The method for preparing the natural rubber-filled nickel-aluminum bimetallic hydroxide multi-walled carbon nanotube composite material according to claim 2, characterized in that, The vulcanization temperature is 120°C, and the vulcanization time is 25 minutes.

10. The application of the natural rubber-filled nickel-aluminum bimetallic hydroxide multi-walled carbon nanotube composite material as described in claim 1 in the field of electronic component packaging.

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