Epoxy resin flame retardant based on hnts@pda-hccp-ta / pba hierarchical hybrid nanoparticles and preparation method and application thereof

Abstract

The application discloses an epoxy resin flame retardant based on HNTs@PDA-HCCP- TA / PBA hierarchical hybrid nanoparticles and a preparation method and application thereof. The flame retardant takes HNTs as a skeleton, forms a hybrid flame retardant with a "corn cob" shape by coating a polyphosphazene hybrid coating on the surface of the skeleton and loading metal organic framework nanoparticles, and utilizes hexachlorocyclotriphosphazene as a bridge to crosslink bio-based tannic acid and dopamine in one step to construct a stable polyphosphazene hybrid coating on the surface of HNTs; 0D structure CoFe-PBA nanoparticles are in-situ grown on the surface of the coating to construct a hierarchical structure. The HNTs@PDA-HCCP- TA / PBA nanoparticles have good interface compatibility and excellent dispersibility in an epoxy resin matrix. When the flame retardant is applied to the epoxy resin, the flame retardant and smoke suppression performance and mechanical properties of the composite material can be simultaneously and significantly improved at a low addition amount.

Description

Technical Field

[0001] This invention belongs to the field of epoxy resin flame retardant modification technology, specifically relating to an epoxy resin flame retardant based on HNTs@PDA-HCCP-TA / PBA 0D-1D hierarchical hybrid nanoparticles, its preparation method and application. Background Technology

[0002] Epoxy resin (EP) has become an indispensable high-performance thermosetting material in aerospace, electronic packaging and other fields due to its excellent adhesion, stability and corrosion resistance. However, its inherent high flammability poses a significant safety hazard.

[0003] Traditional flame retardant strategies often come at the cost of sacrificing the mechanical properties of materials. To achieve a sufficient flame retardant rating, a high amount of additives is often required, which can easily lead to problems such as reduced toughness and damaged strength of epoxy resin, making "high flame retardancy" and "high mechanical properties" a difficult dual objective to achieve simultaneously.

[0004] Nanoparticle flame retardants have attracted much attention due to their unique interfacial effects and physical barrier functions. Among them, halloysite nanotubes (HNTs) are natural tubular aluminosilicate minerals with unique dihydroxyl surface chemistry, exhibiting excellent thermal stability and advantages such as abundant reserves, low cost, and easy availability. Their one-dimensional hollow nanotube morphology offers unique potential for flame retardant applications: their lumens can act as "nanocontainers" to confine and slow-release flame retardants, and their high aspect ratio can effectively construct a physical barrier network to delay heat and mass transfer. However, unmodified or simply core-shell coated nanofillers often consume their surface active groups such as hydroxyl groups, thereby reducing the interfacial interaction between the flame retardant and EP (extractable polymer), resulting in a decrease in the mechanical properties of EP composites.

[0005] Hexachlorocyclotriphosphazene (HCCP) is rich in phosphorus and nitrogen, and can serve as a "bridge" for building cross-linked networks; bio-based tannic acid (TA) and polydopamine (PDA) are rich in polyphenols, hydroxyl groups and amine groups, and not only have strong interfacial adhesion and free radical scavenging capabilities, but also have strong chelation capabilities for metal ions; Prussian blue analogue (PBA, such as CoFe-PBA) nanoparticles, due to their richness in transition metals, have significant advantages in catalytic carbonization and smoke suppression and detoxification.

[0006] Therefore, there is an urgent need to develop a novel flame retardant strategy. This strategy involves modifying the surface of HNTs with an organic-inorganic hybrid structure, integrating the physical barrier effect of the one-dimensional skeleton of HNTs, the gas / solid dual-phase flame retardancy and interface enhancement effect of the PDA-HCCP-TA polyphosphazene hybrid coating, and the highly efficient catalytic smoke suppression function of PBA nanoparticles. This will construct 0D-1D hierarchical nanoparticles, thereby solving the technical bottleneck of simultaneously improving the flame retardancy, smoke suppression and mechanical properties of epoxy resins with low addition amounts. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide an epoxy resin flame retardant based on halloysite nanotubes supported on phosphazene hybrid coated nanoparticles (HNTs@PDA-HCCP-TA / PBA 0D-1D hierarchical structure nanoparticles), which has good compatibility with epoxy resin and excellent flame retardant effect after application.

[0008] The technical solution adopted by the present invention to solve the above-mentioned problems is as follows: A method for preparing HNTs@PDA-HCCP-TA / PBA 0D-1D hierarchical nanoparticles includes the following steps: (1) Synthesis of HNTs@PDA: Halloysite nanotubes (HNTs) were dispersed in Tris-HCl buffer solution, dopamine hydrochloride was added, and the reaction was stirred at room temperature. After the reaction was completed, the mixture was centrifuged, the precipitate was washed and dried to obtain HNTs@PDA powder. (2) Synthesis of HNTs@PDA-HCCP-TA: The HNTs@PDA powder obtained in step (1), hexachlorocyclotriphosphazene (HCCP) and pyridine were added to acetonitrile and mixed evenly. Then, an acetonitrile solution containing tannic acid (TA) was added dropwise. The reaction was stirred at room temperature. After the reaction was completed, the mixture was centrifuged, washed and dried to obtain HNTs@PDA-HCCP-TA powder. (3) Synthesis of HNTs@PDA-HCCP-TA / PBA: The HNTs@PDA-HCCP-TA powder obtained in step (2), cobalt nitrate hexahydrate, and sodium citrate dihydrate were dispersed in deionized water and stirred to prepare solution A; potassium ferricyanide was dissolved in deionized water and added to solution A, and the reaction was continuously stirred at room temperature. After the reaction was completed, the nanoparticles were separated by centrifugation, washed and dried to obtain HNTs@PDA-HCCP-TA / PBA 0D-1D hierarchical structure nanoparticles.

[0009] Preferably, in step (1), the mass ratio of halloysite nanotubes to dopamine hydrochloride is 1:(0.3-0.5). The concentration of the Tris-HCl buffer solution is 5-15 mM, and the pH value is 8.0-9.0; the stirring reaction time is 10-14 hours.

[0010] Preferably, in step (2), the mass ratio of HNTs@PDA powder, hexachlorocyclotriphosphazene, and tannic acid is 1:(0.6-0.9):(0.4-0.6). The stirring reaction time is 5-8 hours.

[0011] Preferably, in step (3), the mass ratio of HNTs@PDA-HCCP-TA powder, cobalt nitrate hexahydrate, and potassium ferricyanide is 1:(0.6-0.8):(0.9-1.2). The mass ratio of cobalt nitrate hexahydrate to sodium citrate dihydrate is 1:(1.2-1.8); and the continuous stirring reaction time is 12-16 hours.

[0012] More preferably, the concentration of the Tris-HCl buffer solution in step (1) is 10 mM, the stirring reaction time is 12 hours, and the drying temperature is 80℃.

[0013] More preferably, the stirring reaction time in step (2) is 6 hours.

[0014] More preferably, the duration of the continuous stirring reaction in step (3) is 14 hours.

[0015] Preferably, in steps (1), (2), and (3), the drying temperature is 70-90°C and the drying time is 8-16 hours.

[0016] An epoxy resin flame retardant based on HNTs@PDA-HCCP-TA / PBA 0D-1D hierarchical nanoparticles is prepared by compositing HNTs@PDA-HCCP-TA / PBA nanoparticles with epoxy resin to obtain an epoxy resin / HNTs@PDA-HCCP-TA / PBA composite material. The preparation method includes the following steps: (a) The HNTs@PDA-HCCP-TA / PBA prepared by the above method were dispersed in water and subjected to ultrasonic treatment; (b) Add the dispersion to the epoxy resin and stir. (c) Add 20-30 wt% of diaminodiphenylmethane (DDM) curing agent to the epoxy resin, mix well and then inject into the mold; (d) Heating and curing to obtain epoxy resin / HNTs@PDA-HCCP-TA / PBA composite material.

[0017] Preferably, the amount of HNTs@PDA-HCCP-TA / PBA added is 1-10 wt% of the epoxy resin mass.

[0018] The method described above yields HNTs@PDA-HCCP-TA / PBA 0D-1D hierarchical nanoparticles, which possess a hierarchical structure consisting of a one-dimensional halloysite nanotube (HNTs) framework, a stable polyphosphazene coating (PDA-HCCP-TA), and Prussian blue analogue (CoFe-PBA) nanoparticles grown in situ on the surface. This structure uses HCCP as a "bridge," forming a hybrid coating through a one-step covalent crosslinking of bio-based tannic acid (TA) with polydopamine (PDA), thereby utilizing TA's chelating ability for metal ions to in situ anchor PBA particles.

[0019] The above method yields an epoxy resin / HNTs@PDA-HCCP-TA / PBA composite material, in which the epoxy resin is a continuous phase, and HNTs@PDA-HCCP-TA / PBA hierarchical particles are uniformly dispersed. Its unique hierarchical structure (corn stick structure) not only endows the particles with excellent stability, but also constructs a highly interactive interface layer through multiple hydrogen bonds and mechanical interlocking between the outer CoFe-PBA layer and the epoxy resin matrix. This achieves efficient stress transfer and energy dissipation in the composite material, significantly improving the flexural strength and impact toughness of the composite material.

[0020] The HNTs@PDA-HCCP-TA / PBA nanoparticles and epoxy resin / HNTs@PDA-HCCP-TA / PBA composite materials prepared by this invention can be applied in aerospace, electronic packaging, coatings or adhesives and other fields.

[0021] The flame retardant prepared by this invention uses natural tubular HNTs as a carrier and integrates multiple flame retardant mechanisms, including gas-phase free radical quenching, condensed-phase catalytic char formation, and physical barriers. Specifically, in the gas phase, the flame retardant releases phosphorus-containing free radicals (quenching active free radicals) and nitrogen-containing non-combustible gases (diluting combustibles) upon heating. Simultaneously, the transition metal components (Co, Fe) in PBA catalyze the conversion of CO to CO2 to reduce smoke toxicity. In the condensed phase, TA acts as a char source, and the phosphoric acid substances generated by HCCP and the transition metals synergistically catalyze char formation, forming a dense thermal barrier together with the HNT framework. The flame retardant provided by this invention has the advantages of high-efficiency flame retardancy with low addition levels, significant smoke suppression and toxicity reduction, and simultaneous improvement of mechanical properties.

[0022] Compared with existing technologies, the beneficial effects of the present invention are as follows: 1. Overcoming performance constraints: This invention, through innovative component and structural design, constructs a hybrid flame retardant with an 0D-1D hierarchical structure, HNTs@PDA-HCCP-TA / PBA, which solves the technical bottleneck of high addition amounts of traditional flame retardants damaging mechanical properties.

[0023] 2. High-efficiency flame retardancy with low addition amount: When the obtained flame retardant is added at only 5 wt%, the UL-94 rating of epoxy resin composite material can reach the V-0 level, and the limiting oxygen index (LOI) can be increased to 31.2%.

[0024] 3. Significantly reduces smoke and toxicity: The peak heat release rate (pHRR), total smoke release (TSP), and CO generation of the composite material are significantly reduced by 31.71%, 49.77%, and 26.67% respectively compared with pure epoxy resin.

[0025] 4. Simultaneous improvement of mechanical properties: Thanks to the significant improvement of interfacial compatibility due to the hierarchical structure, the flexural strength, flexural modulus and impact strength of the composite material increased by 22.17%, 12.32% and 29.51% respectively compared with the pure resin. Attached Figure Description

[0026] Figure 1 These are scanning electron microscope images of HNT, PNT powder, HTA powder, and PHA 0D-1D hierarchical nanoparticles prepared in Example 1.

[0027] Figure 2 The images show the XRD patterns of HNT, PNT powder, HTA powder, and PHA 0D-1D hierarchical nanoparticles prepared in Example 1.

[0028] Figure 3 The images show the infrared spectra of HNT, PNT powder, HTA powder, and PHA 0D-1D hierarchical nanoparticles prepared in Example 1.

[0029] Figure 4 The diagram shows the flexural strength, flexural modulus, and impact strength of pure EP, EP / 5% HNT, EP / 5% PNT, EP / 5% HTA, and EP / 5% PHA in Example 4. Detailed Implementation

[0030] To better understand the present invention, specific embodiments are given below for further explanation. It should be noted that the following embodiments should not be construed as limiting the scope of protection of the present invention, that is, the present invention is not limited to the following embodiments.

[0031] Example 1 A method for preparing HNTs@PDA-HCCP-TA / PBA 0D-1D hierarchical nanoparticles (PHA) includes the following steps: (1) 0.2 g of halloysite nanotubes (HNTs) dried overnight in a vacuum oven at 80 °C were ultrasonically dispersed in 20 mL of Tris-HCl buffer solution (concentration 10 mM, pH=8.5). Then, 0.08 g of dopamine hydrochloride PDA·HCl (mass ratio 1:0.4) was added, and the mixture was stirred at room temperature for 12 hours. After the reaction was completed, the precipitate was collected by centrifugation, washed with deionized water and ethanol, and dried overnight at 80 °C to obtain brown powdered HNTs@PDA (PNT).

[0032] (2) Add 0.2 g PNT, 0.15 g hexachlorocyclotriphosphazene (HCCP), and 1 mL pyridine obtained in step (1) to a round-bottom flask equipped with a magnetic stirrer, pour in 20 mL acetonitrile, mix thoroughly, and then add dropwise 0.1 g tannic acid (TA) dissolved in 5 mL acetonitrile. After reacting at room temperature for 6 hours, centrifuge to collect the precipitate, wash with deionized water and ethanol, and dry at 80 °C overnight to obtain a brownish-black powder HNTs@PDA-HCCP-TA (HTA).

[0033] (3) Take 0.2 g HTA, 0.14 g cobalt nitrate hexahydrate (Co(NO3)2·6H2O) and 0.212 g sodium citrate dihydrate obtained in step (2) and disperse them in 25 mL of deionized water. Stir for 30 minutes to obtain solution A. Take another 0.212 g potassium ferricyanide (K3[Fe(CN)6]) and add it to 25 mL of deionized water. After it dissolves, pour it into solution A. Stir continuously at room temperature for 14 hours, then centrifuge to collect the precipitate. Wash it with deionized water and ethanol, and dry it at 80℃ overnight to obtain black powder HNTs@PDA-HCCP-TA / PBA (PHA).

[0034] Example 2 (1) 0.2 g of HNTs were ultrasonically dispersed in 20 mL of Tris-HCl buffer solution (5 mM, pH=8.0). 0.06 g of dopamine hydrochloride (mass ratio 1:0.3) was added, and the mixture was stirred at room temperature for 10 hours. The precipitate was collected by centrifugation, washed, and dried at 70 °C overnight to obtain HNTs@PDA (PNT).

[0035] (2) Add 0.2 g PNT, 0.12 g HCCP and 1 mL pyridine to 20 mL acetonitrile and mix well. Add 0.08 g TA dissolved in 5 mL acetonitrile dropwise. After reacting at room temperature for 5 hours, centrifuge and wash, and dry at 70 °C overnight to obtain HNTs@PDA-HCCP-TA (HTA).

[0036] (3) Disperse 0.2 g HTA, 0.12 g cobalt nitrate hexahydrate and 0.18 g sodium citrate dihydrate in 25 mL of deionized water and stir for 30 minutes to obtain solution A. Dissolve 0.18 g potassium ferricyanide in 25 mL of deionized water and pour it into solution A. Stir at room temperature for 12 hours, centrifuge and wash, and dry at 70 °C overnight to obtain HNTs@PDA-HCCP-TA / PBA (PHA).

[0037] Example 3 (1) 0.2 g of HNTs were ultrasonically dispersed in 20 mL of Tris-HCl buffer solution (concentration 15 mM, pH=9.0). 0.1 g of dopamine hydrochloride (mass ratio 1:0.5) was added, and the mixture was stirred at room temperature for 14 hours. The precipitate was collected by centrifugation, washed, and dried at 90 °C overnight to obtain HNTs@PDA (PNT).

[0038] (2) Add 0.2 g PNT, 0.18 g HCCP and 1 mL pyridine to 20 mL acetonitrile and mix well. Add 0.12 g TA dissolved in 5 mL acetonitrile dropwise. After reacting at room temperature for 8 hours, centrifuge and wash, and dry at 90 °C overnight to obtain HNTs@PDA-HCCP-TA (HTA).

[0039] (3) Disperse 0.2 g HTA, 0.16 g cobalt nitrate hexahydrate and 0.24 g sodium citrate dihydrate in 25 mL of deionized water and stir for 30 minutes to obtain solution A. Dissolve 0.24 g potassium ferricyanide in 25 mL of deionized water and pour it into solution A. Stir at room temperature for 16 hours, centrifuge and wash, and dry at 90 °C overnight to obtain HNTs@PDA-HCCP-TA / PBA (PHA).

[0040] Comparative Example 1 Mix 100 g of bisphenol A type epoxy resin (E-44) and 25 g of epoxy resin curing agent 4,4'-diaminodiphenylmethane (DDM), then degas the mixture, pour it into a preheated mold, and perform step curing (e.g., curing at 100℃ for 2 hours, then curing at 150℃ for 2 hours). After cooling and demolding, a pure epoxy resin sample (EP) can be obtained.

[0041] Example 4 Halloysite nanotubes (HNTs), PNT powder, HTA powder, and PHA hierarchical nanoparticles prepared in Example 1 were added to epoxy resin as flame retardant fillers. The specific formulation was: epoxy resin E-44 (100 g), flame retardant filler (5 g), and DDM curing agent (25 g). During preparation, 5 g of the corresponding flame retardant (HNTs, PNT, HTA, or PHA) was first ultrasonically dispersed in 50 ml of water, then 100 g of epoxy resin was added and stirred until homogeneous. Subsequently, 25 g of DDM curing agent was added and mixed thoroughly. After degassing, the mixture was poured into a preheated mold for step curing. After cooling and demolding, composite materials with corresponding 5 wt% addition amounts were obtained: EP / 5% HNT, EP / 5% PNT, EP / 5% HTA, and EP / 5% PHA.

[0042] Figure 1 (a), (b), (c), and (d) are SEM images of the original HNT and PNT powders prepared in step (1) of Example 1, the HTA powder prepared in step (2), and the PHA 0D-1D hierarchical nanoparticles prepared in step (3), respectively. The synthesized original HNTs exhibit a typical hollow tubular structure with a smooth but slightly agglomerated surface. After PDA modification, the surface roughness of PNTs increased, and the dispersibility was improved. After introducing HCCP-TA copolymerization modification, the surface coating of HTA became rougher. For PHA, its dispersibility was further improved. The SEM images showed that its surface was uniformly coated with particulate matter. These particles were Prussian blue analogues (PBA) with cubic morphology, which were generated in situ on the surface of HNTs@PDA-HCCP-TA, indicating that HNTs and PBA successfully formed a hybrid structure. The entire product exhibits a unique hierarchical structure (corncob-like structure).

[0043] Figure 2 The XRD patterns of HNT, PNT, HTA, and PHA prepared in Example 1 show that unmodified HNT exhibits diffraction peaks at 12.1°, 20.1°, 24.9°, 35.0°, and 62.6°. The spectra of PNT and HTA retain the characteristic peak shape of HNT, but their diffraction intensity is weakened, attributed to the encapsulation effect of the surface organic coating. Furthermore, the PHA spectrum shows new diffraction peaks at 17.2°, 24.4°, and 34.8°, which are characteristic peaks of the Prussian blue analogue (PBA). The PHA spectrum shows the coexistence of HNT and PBA diffraction peaks, with some peak positions showing overlap and broadening, directly confirming the successful formation of a hybrid structure.

[0044] Figure 3The infrared spectra of HNT, PNT, HTA, and PHA prepared in Example 1 show that the unmodified HNT has a wavelength of 3694 cm⁻¹. -1 3620 cm -1 and 910 cm -1 The characteristic peak of Al-OH appears at 1030 cm⁻¹. -1 and 794 cm -1 A Si-O-Si stretching vibration peak appears at this location. The modified HNT exhibits several distinct characteristic peaks, such as the P=N stretching vibration (1200 cm⁻¹) attributed to HCCP. -1 ), belonging to the benzene ring of TA (1612 cm) -1 ), ester bond C=O (1728 cm) -1 ), and the tensile vibrations (2100-2300 cm) attributed to the cyano group in CoFe-PBA. -1 ) and tensile vibration of Fe-C / Co-C (594 cm) -1 These results collectively demonstrate the successful assembly of the PDA-HCCP-TA / PBA coating on the HNT surface.

[0045] In Example 4, the LOI and UL-94 tests of EP, EP / 5% HNT, EP / 5% PNT, EP / 5% HTA, and EP / 5% PHA showed that the LOI value of pure EP was only 24.4%, failing to reach any UL-94 rating. Adding 5 wt% HNT increased the LOI value to 26.7%. Notably, the introduction of the PDA-HCCP-TA coating and PBA significantly improved the flame retardancy of the EP composite material, as evidenced by a gradual increase in the LOI value. The EP / 5% PHA composite material exhibited the best performance, reaching a maximum LOI of 31.2%, and also achieved a V-0 rating in the UL-94 test.

[0046] Figure 4 The graph shows the flexural strength, flexural modulus, and impact strength of pure EP and various composite materials in Example 4. It can be seen that compared to pure EP (flexural strength 79.78 MPa, flexural modulus 1896.81 MPa, impact strength 14.67 kJ / m²), the flexural strength of pure EP is significantly higher. 2 Compared to pure EP, the addition of 5 wt% HNT resulted in a decrease in flexural properties, mainly due to its weak interfacial bonding with the matrix. However, the hierarchical structure of PHA effectively improved mechanical properties; the flexural strength (97.47 MPa) and flexural modulus (2130.66 MPa) of the EP / 5% PHA composite were significantly increased by 22.17% and 12.32% respectively compared to pure EP, and the impact strength reached 19 kJ / m². 2The performance was improved by 29.51% compared to pure EP. This can be attributed to the unique corn-rod structure of PHA, which can construct a stronger interfacial layer through multiple hydrogen bonds and mechanical interlocking between the outer CoFe-PBA layer and the EP matrix, thus exhibiting superior mechanical properties.

Claims

1. A method for preparing an HNTs@PDA-HCCP-TA / PBA hybrid flame retardant, characterized in that, Includes the following steps: (1) Synthesis of HNTs@PDA: Halloysite nanotubes (HNTs) were dispersed in Tris-HCl buffer solution, dopamine hydrochloride was added, the reaction was stirred at room temperature, and the mixture was centrifuged, washed and dried to obtain HNTs@PDA powder. (2) Synthesis of HNTs@PDA-HCCP-TA: The HNTs@PDA powder obtained in step (1), hexachlorocyclotriphosphazene (HCCP) and pyridine were added to acetonitrile and mixed evenly. Then, an acetonitrile solution containing tannic acid TA was added dropwise. The mixture was stirred at room temperature, centrifuged, washed and dried to obtain HNTs@PDA-HCCP-TA powder. (3) Synthesis of HNTs@PDA-HCCP-TA / PBA: The HNTs@PDA-HCCP-TA powder obtained in step (2), cobalt nitrate hexahydrate, and sodium citrate dihydrate were dispersed in deionized water and stirred to prepare solution A; potassium ferricyanide was dissolved in deionized water and added to solution A, and the reaction was continuously stirred at room temperature. After centrifugation, washing, and drying, HNTs@PDA-HCCP-TA / PBA hybrid flame retardant with 0D-1D hierarchical structure was obtained.

2. The preparation method according to claim 1, characterized in that, In step (1), the mass ratio of halloysite nanotubes to dopamine hydrochloride is 1:(0.3-0.5); the concentration of the Tris-HCl buffer solution is 5-15 mM and the pH value is 8.0-9.0; the stirring reaction time is 10-14 hours.

3. The preparation method according to claim 1, characterized in that, In step (2), the mass ratio of HNTs@PDA powder, hexachlorocyclotriphosphazene and tannic acid is 1:(0.6-0.9):(0.4-0.6); the stirring reaction time is 5-8 hours.

4. The preparation method according to claim 1, characterized in that, In step (3), the mass ratio of HNTs@PDA-HCCP-TA powder, cobalt nitrate hexahydrate and potassium ferricyanide is 1:(0.6-0.8):(0.9-1.2); the mass ratio of cobalt nitrate hexahydrate and sodium citrate dihydrate is 1:(1.2-1.8); and the continuous stirring reaction time is 12-16 hours.

5. The preparation method according to claim 1, characterized in that, In steps (1), (2), and (3), the drying temperature is 70-90℃ and the drying time is 8-16 hours.

6. A method for preparing an epoxy resin / HNTs@PDA-HCCP-TA / PBA composite material, characterized in that, Includes the following steps: (a) Disperse the HNTs@PDA-HCCP-TA / PBA hybrid flame retardant obtained by any of the preparation methods described in claims 1-5 in water and treat it with ultrasound; (b) Add the dispersion to the epoxy resin and stir. (c) Add diaminodiphenylmethane curing agent, mix well and then inject into the mold; (d) Heating and curing to obtain epoxy resin / HNTs@PDA-HCCP-TA / PBA composite material.

7. The preparation method according to claim 6, characterized in that, The amount of HNTs@PDA-HCCP-TA / PBA hybrid flame retardant added is 1-10 wt% of the epoxy resin mass; the amount of diaminodiphenylmethane added is 20-30 wt% of the epoxy resin mass.

8. The HNTs@PDA-HCCP-TA / PBA hybrid flame retardant obtained by the preparation method according to any one of claims 1-5.

9. An epoxy resin / HNTs@PDA-HCCP-TA / PBA composite material obtained by the preparation method according to any one of claims 6-7.

10. The application of the HNTs@PDA-HCCP-TA / PBA hybrid flame retardant of claim 8 or the epoxy resin / HNTs@PDA-HCCP-TA / PBA composite material of claim 9 in aerospace, electronic packaging, coatings or adhesives.

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