Anti-aging cyclophosphazene metal framework nano flame retardant, preparation and application thereof

Abstract

The application relates to an anti-aging cyclotriphosphazene metal framework structure nanometer flame retardant, preparation and application, and belongs to the technical field of nanometer materials and flame retardation. 2-amino pyrazine and a cobalt-based metal organic framework ZIF-67 are dissolved in an organic solvent, heating is performed to 55-80 DEG C, a hexachlorocyclotriphosphazene solution is added, continuous heating and stirring are performed to reflux reaction for 8-24 hours, after the reaction is completed, the precipitate is collected, washing and vacuum drying are performed, and an anti-aging cyclotriphosphazene metal framework structure nanometer flame retardant is obtained. By combining a phosphazene flame retardant and a metal organic framework, an anti-aging cyclotriphosphazene metal framework structure flame retardant containing an acid source, a gas source and a carbon source is obtained. The flame retardant has excellent flame retardation effect and anti-aging capability. As a high polymer system flame retardant, the flame retardant has good compatibility with a high polymer system matrix, the decomposition temperature is matched with the matrix, and the flame retardant can quickly play a flame retardation effect before the matrix burns.

Description

TECHNICAL FIELD

[0001] The application relates to an anti-aging cyclophosphazene metal framework nano flame retardant, preparation and application thereof, and belongs to the technical field of nanomaterials and flame retardants. BACKGROUND

[0002] Epoxy resins are widely used in the electronics packaging and mechanical fields, benefiting from their excellent mechanical properties and electrical insulation, as well as their ability to remain stable under various environmental conditions. In addition, epoxy resins also have a place in the construction materials field due to their low cost and ease of processing into shapes, such as for flooring materials, pipes, and waterproof coatings. Epoxy resins have a very wide range of applications, of which 38% are used in the construction and coatings industry, which includes the reinforcement of building structures, anticorrosive coatings, and decorative coatings; 22% are used in the electronics and mechanical industries, mainly for the packaging of circuit boards and capacitors, and as structural materials. With the continued growth of the manufacturing market demand, the demand for epoxy resins is also increasing. Although epoxy resins have excellent mechanical properties, electrical insulation, and processing performance, their flammability limits their application in certain fields, especially in situations where there are strict requirements for flame retardant properties. Since the flame of epoxy resins does not self-extinguish after being away from the fire, this undoubtedly increases the risk of fire, so it is crucial to improve the flame retardant properties of epoxy resins.

[0003] At the same time, some epoxy resins used outdoors are exposed to sunlight for a long time, and the short-wave part (especially UV-C and part of UV-B) of ultraviolet light has high energy, which can break the chemical bonds in the epoxy chain, leading to molecular chain rupture and thus degradation. This degradation process reduces the molecular weight of the material, affecting its physical and mechanical properties. At the same time, ultraviolet radiation can accelerate the oxidation reaction of epoxy resins, generating free radicals, which further react with oxygen to form peroxides and carbonyl compounds, causing the material surface to powder, crack, lose gloss, and also cause the material as a whole to discolor, which is called aging. In view of the current demand, improving the flame retardant and anti-aging properties of polymer materials has become the focus of materials science. By adding phosphorus-based, halogen-based, and inorganic flame retardants, the flame retardancy of the material can be effectively enhanced, and the use of ultraviolet shielding agents can delay the aging of epoxy resins. However, the addition of additives introduces new challenges: burning smoke pollution, reduced compatibility with the matrix, and potential effects on mechanical and processing properties, which all need to be balanced in the optimization of material properties.

[0004] With the development of the research on metal-organic frameworks (MOFs) materials, the application requirements of multifunctional MOFs materials are increasing, especially the combination of them with polymers has become a popular research field. Aiming at the key problem of polymer materials-fire risk, the compatibility of traditional inorganic flame retardants with polymer matrix is often poor, while the molecular weight distribution of organic flame retardants is uneven and the thermal stability is poor. MOFs materials can avoid these defects and show great potential as organic-inorganic hybrid materials. Under the electric field of the surrounding ligand, the five degenerate d orbitals of the metal ion split. Some energy increases, and some energy decreases. This effect of splitting the energy level of the central ion d orbital due to the electric field of the ligand is the coordination field effect. Some MOF materials have a large number of transition metal ions, and the transition metal ions have partially filled d orbitals. When excited by photon energy, the electrons on the d orbital can jump from the low-energy state d orbital to the high-energy state d orbital under the action of the coordination field. This electron transition process is accompanied by the absorption of light of a specific wavelength, thereby producing a unique absorption spectrum. This transition is called d-d electron transition, which is also called coordination field transition. This phenomenon not only enriches the types of organic ultraviolet shielding materials, but also provides new possibilities for the development of high-performance ultraviolet protection materials.

[0005] Phosphazene flame retardants are known for their unique P-N atom alternating main chain structure, showing the variability of cyclic or linear structure, and excellent flame retardant effect. Such flame retardants not only have excellent thermal stability and excellent oxidation resistance, but also have good biocompatibility and biodegradability. At the same time, their optical and mechanical physical properties are also outstanding. Combining the advantages of inorganic and organic compounds, phosphazene flame retardants effectively improve the performance of materials through the synergistic effect of P-N. In particular, hexachlorocyclotriphosphazene as a typical phosphazene flame retardant, its six-membered ring structure constructed by P-N skeleton endows it with high thermal stability and flame retardancy. The π-π conjugation effect in the structure enhances its ability to absorb ultraviolet rays, and the high activity of phosphorus-chlorine bond enables it to react efficiently with active functional groups such as hydroxyl groups, facilitating the synthesis of customized flame retardants.

[0006] Currently, there is no related report on the combination of MOFs materials and phosphazene flame retardants. SUMMARY

[0007] In order to overcome the problems of current small molecule flame retardants, such as large amount, poor flame retardant effect, poor compatibility with matrix material, easy to precipitate and invalid, and large amount of smoke harmful to the environment, and the problems of poor char yield and single function of some small molecule flame retardants, the present application aims to provide an anti-aging cyclophosphazene metal framework structure nano flame retardant, preparation and application. The combination of phosphazene flame retardant and metal organic framework obtains an anti-aging phosphazene metal framework structure flame retardant containing acid source, gas source and carbon source.

[0008] In order to achieve the above-mentioned purpose, the technical scheme of the present application is as follows.

[0009] A preparation method of an anti-aging cyclophosphazene metal framework structure nano flame retardant, the method steps comprising:

[0010] 2-amino pyrazine and cobalt-based metal organic framework ZIF-67 are dissolved in an organic solvent, heated to 55-80 DEG C, and a hexachlorocyclotriphosphazene solution is added, and the reaction is refluxed and stirred for 8-24h, after the reaction is completed, the precipitate is collected, washed and vacuum dried to obtain an anti-aging cyclophosphazene metal framework structure nano flame retardant.

[0011] Preferably, the mass ratio of 2-amino pyrazine, ZIF-67 and hexachlorocyclotriphosphazene is 1:1-10:1-4. More preferably, the mass ratio of 2-amino pyrazine, ZIF-67 and hexachlorocyclotriphosphazene is 1:2-6:2-3.

[0012] Preferably, the organic solvent is one or more of tetrahydrofuran, anhydrous acetonitrile, acetone and dichloromethane.

[0013] Preferably, the solvent of the hexachlorocyclotriphosphazene solution is tetrahydrofuran.

[0014] Preferably, the hexachlorocyclotriphosphazene solution is added within 30min.

[0015] Preferably, the reaction temperature is 60-70 DEG C, and the reaction time is 12-18h.

[0016] Preferably, the stirring rate is 300-400rpm.

[0017] Preferably, the drying temperature is 50-70 DEG C, and the drying time is 8-16h.

[0018] Preferably, the cobalt-based metal organic framework ZIF-67 is prepared by the following method, the method steps comprising: dissolving cobalt nitrate hexahydrate in solvent A to obtain a cobalt salt solution; dissolving 2-methylimidazole in solvent B to obtain a 2-methylimidazole solution; adding the 2-methylimidazole solution to the cobalt salt solution, standing at 15-40 DEG C for 8-32 h, after standing, centrifuging at a speed of 6000-12000 rad / min for 3-8 min, washing with anhydrous ethanol, and drying at 50-70 DEG C for 8-16 h to obtain ZIF-67.

[0019] Preferably, the molar ratio of cobalt nitrate hexahydrate to 2-methylimidazole is 1:4-10.

[0020] Preferably, the standing temperature is 25-35 DEG C.

[0021] Preferably, the centrifuging time is 4-6 min.

[0022] Preferably, the solvent A and solvent B are one or more of anhydrous methanol, anhydrous ethanol and water.

[0023] An anti-aging cyclophosphazene metal framework structure nanometer flame retardant is prepared by the above method.

[0024] An application of the anti-aging cyclophosphazene metal framework structure nanometer flame retardant of the present application, wherein the flame retardant is used as a flame retardant for a high polymer system.

[0025] Advantages

[0026] The present application provides an anti-aging cyclophosphazene metal framework structure nanometer flame retardant, which has excellent flame retardant effect and anti-aging ability. The polycyclic structure of the flame retardant has high flame retardant efficiency and good dispersibility, and can increase the flowability and transparency during the processing of epoxy resin, thereby better synergistic effect, and the polycyclic structure can enhance the absorption of ultraviolet rays. The introduction of the metal organic framework can promote the formation of smoke and heat insulation carbon layer, improve the flame retardant effect, and the introduction of transition metal can further improve the anti-aging ability (especially the ultraviolet absorption ability) of the flame retardant. Compared with the existing single-chain or branched-chain phosphorus / nitrogen flame retardant, the small molecule cyclophosphazene metal framework structure nanometer flame retardant has more excellent synergistic flame retardant effect.

[0027] The flame retardant is a high-efficiency intumescent flame retardant integrating three sources (acid source, gas source and carbon source), does not need to be used in combination with other flame retardants, and has no obvious loss on the mechanical properties of the polymer material such as epoxy resin after being added. The flame retardant has good compatibility with the polymer system matrix, the decomposition temperature is matched with the matrix, can quickly play a flame-retardant effect before the matrix burns, can increase the flowability of the matrix, is beneficial to processing and molding, and can increase the transparency of the matrix, which is beneficial to color adjustment.

[0028] The flame retardant can make the vertical burning test level of the flame-retardant epoxy resin reach UL-94 V0 level when the addition amount is 2%; the peak heat release rate can be reduced by 35%, and the total heat release can be reduced by 28%. The flame retardant can make the ultraviolet shielding capacity of the epoxy resin system increase by 40%. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The scanning electron microscope image of the intermediate purple powder ZIF-67 synthesized in the embodiment 1 of the present application.

[0030] Figure 2 The scanning electron microscope image of the phosphazene metal framework structure nanometer flame retardant synthesized in the embodiment 1 of the present application.

[0031] Figure 3 The transmission electron microscope image of the phosphazene metal framework structure nanometer flame retardant synthesized in the embodiment 1 of the present application.

[0032] Figure 4 The EDS image of the phosphazene metal framework structure nanometer flame retardant synthesized in the embodiment 1 of the present application.

[0033] Figure 5 The peak heat release rate image of the epoxy resin and the composite system thereof in the embodiment 1 of the present application.

[0034] Figure 6 The total smoke release image of the epoxy resin and the composite system thereof in the embodiment 1 of the present application.

[0035] Figure 7 The infrared contrast image of ether compound release after combustion of the epoxy resin and the composite system thereof in the embodiment 1 of the present application.

[0036] Figure 8 The infrared contrast image of aromatic compound release after combustion of the epoxy resin and the composite system thereof in the embodiment 1 of the present application.

[0037] Figure 9 The infrared contrast image of hydrocarbon compound release after combustion of the epoxy resin and the composite system thereof in the embodiment 1 of the present application.

[0038] Figure 10 The ultraviolet transmittance image of the epoxy resin and the composite system thereof in the embodiment 1 of the present application. DETAILED DESCRIPTION

[0039] The application will be further described in detail below in connection with specific examples.

[0040] 3.64 g of cobalt nitrate hexahydrate was added to 50 mL of anhydrous ethanol and ultrasonically treated for 5 min to obtain a uniform mixture, as solution A. Then, solution A was poured into a 200 mL beaker. 4.12 g of 2-methylimidazole was dissolved in 50 mL of anhydrous ethanol and ultrasonically treated for 5 min, as solution B. Solution B was added to the beaker containing solution A. After being sealed and standing at 30°C for 24 h, the mixture was transferred to a centrifuge and centrifuged at 8000 rad / min for 5 min. Then, the mixture was washed twice with 10 mL of anhydrous ethanol and dried in a vacuum oven at 50°C and 1 KPa for 12 h to obtain a constant weight, to obtain a reaction intermediate ZIF-67 in purple powder form. Figure 1

[0041] 2 g of 2-aminopyrazine and 3 g of ZIF-67 were weighed and dissolved in 150 mL of tetrahydrofuran solution and ultrasonically treated for 10 min to obtain a uniform dispersion, as solution C. Then, solution C was added to a 250 mL three-necked flask, which was connected to a 100 mL constant-pressure dropping funnel, a magnetic stirrer, a 24-port serpentine condenser, and an exhaust gas receiving and processing device. The mixture was heated to 70°C while stirring. 1 g of hexachlorocyclotriphosphazene was dissolved in 35 mL of tetrahydrofuran solution and stirred at room temperature and normal pressure until it became clear and transparent, as solution D. Then, solution D was added to the constant-pressure dropping funnel. The flow rate was adjusted to 30 min for complete dripping. The stirring was continued for 8 h to complete the reaction. The precipitate was suction-filtered and washed three times alternately with 10 mL of tetrahydrofuran and 10 mL of acetone. Then, the mixture was dried in a vacuum oven at 60°C and 1 KPa for 8 h to obtain 4.386 g of green powder flame retardant, with a yield of 73.1%. Figures 2-4

[0042] 150 g of epoxy resin E-44 was used as the matrix and poured into a 200 mL beaker. The beaker was placed in an oven at 80°C and mechanically stirred at a speed of 400 r / min. Meanwhile, 35 g of 4,4'-diaminodiphenyl methane was weighed into a 50 mL beaker and placed in an oven at 120°C for 20 min to melt. Then, 3.75 g of the flame retardant prepared in this example was dissolved in 30 mL of acetone by ultrasonic treatment for 5 min. The mixture was poured into the epoxy resin system and further stirred. After about 30 min, the acetone in the epoxy resin system was completely volatilized. The melted curing agent was poured into the epoxy resin system and stirred for 1 min until the system was uniform. Then, the system was poured into a mold and cured at 130°C for 4 h to obtain an epoxy resin composite material. ​​

[0043] The obtained epoxy resin composite was subjected to limiting oxygen index test (LOI), and the measured limiting oxygen index value was 27.9%. Vertical burning experiment test (UL-94) was performed, and the obtained flame retardant grade was V-1 grade. Further, cone calorimeter test was performed, and the peak heat release rate was reduced by 40.2% relative to the pure epoxy system, the total heat release was reduced by 29.1% relative to the pure epoxy system, the carbon dioxide yield was reduced by 45%, and the carbon monoxide yield was reduced by 1%. The epoxy system was also subjected to mechanical property test and ultraviolet diffuse reflection test, and the results showed that the tensile strength of the epoxy composite system was not significantly different from that of the pure epoxy system, the ultraviolet transmittance was reduced by 45%, and the peak heat release rate and total smoke release of the epoxy resin and its composite system were as shown in Figure 5 、 6 The infrared contrast chart of ether, aromatic and hydrocarbon release after combustion of the epoxy resin and its composite system was as shown in Figures 7-9 , and the ultraviolet transmittance chart was as shown in Figure 10 .

[0044] Example 2

[0045] 7.28 g of cobalt nitrate hexahydrate was added to 100 mL of anhydrous ethanol and ultrasonically treated for 5 min to uniformly mix the system, as solution A, then solution A was poured into a 250 mL beaker, 8.24 g of 2-methylimidazole was dissolved in 100 mL of anhydrous ethanol and ultrasonically treated for 5 min, as solution B, solution B was added to the beaker containing solution A, and after sealing and standing at 30°C for 24 h, it was transferred to a centrifuge and centrifuged at a speed of 8000 rad / min for 5 min, then washed with anhydrous ethanol twice, and dried in a vacuum oven at 50°C and 1 KPa for 12 h to constant weight, to obtain the reaction intermediate ZIF-67.

[0046] 4 g of 2-aminopyrazine and 6 g of ZIF-67 were weighed and dissolved in 250 mL of tetrahydrofuran solution and ultrasonically treated for 10 min to uniformly disperse, as solution C, then solution C was added to a 500 mL three-necked flask, and a 100 mL constant-pressure dropping funnel, magnetic stirring, 24-port snake-shaped condenser, and tail gas receiving and processing device were connected, and the temperature was raised to 70°C under stirring. 2 g of hexachlorocyclotriphosphazene was dissolved in 70 mL of tetrahydrofuran solution under normal temperature and pressure, and stirred until clear and transparent, as solution D, then solution D was added to the constant-pressure funnel, and the flow rate was adjusted to 30 min for dropwise addition, and the stirring reaction was continued for 12 h to end, the precipitate was suction filtered, and then washed with 20 mL of tetrahydrofuran and 20 mL of acetone alternately for three times, then dried in a vacuum oven at 60°C and 1 KPa for 12 h, to obtain 8.726 g of green powder flame retardant, with a yield of 72.7%.

[0047] Epoxy resin E-44 150 g was used as the matrix, which was poured into a 200 mL beaker and mechanically stirred at 80 °C with an open condition at a speed of 400 r / min. Meanwhile, 35 g of 4,4'-diaminodiphenyl methane was weighed as a curing agent in a 50 mL beaker and placed in a 120 °C oven for 20 min to melt. Then, 3.75 g of the flame retardant prepared in this example was dissolved in 30 mL of acetone, and after ultrasonic treatment for 5 min, it was poured into the epoxy resin system for further stirring. After 30 min, the acetone in the epoxy system was completely volatilized, the melted curing agent was poured into the epoxy resin system and stirred for 1 min until the system was uniform, then the system was poured into a mold and cured at 130 °C for 4 h to obtain an epoxy resin composite.

[0048] The obtained epoxy resin composite was tested by limiting oxygen index (LOI), and the measured limiting oxygen index value was 28.2%. The vertical burning experiment test (UL-94) obtained a flame retardant grade of V-level. Further, the cone calorimeter test was carried out, and the peak heat release rate was reduced by 39.4% relative to the pure epoxy system, the total heat release was reduced by 28.3% relative to the pure epoxy system, the carbon dioxide yield was reduced by 43%, and the carbon monoxide yield was reduced by 38%. The epoxy system was also tested for mechanical properties and ultraviolet diffuse reflectance, and the results showed that the tensile strength of the epoxy composite system was not significantly different from the pure epoxy system, and the ultraviolet transmittance was reduced by 38%.

[0049] Example 3

[0050] 14.5 g of cobalt nitrate hexahydrate was added to 300 mL of anhydrous ethanol and ultrasonically treated for 10 min to obtain a uniform mixture as solution A. Then, 16.48 g of 2-methylimidazole was dissolved in 300 mL of anhydrous ethanol by ultrasonic treatment for 10 min as solution B. Solution B was added to the beaker containing solution A, and the beaker was sealed and placed at 30 °C for 24 h. Then, the beaker was transferred to a centrifuge and centrifuged at a speed of 8000 rad / min for 5 min. Then, the beaker was washed with anhydrous ethanol twice and dried in a vacuum oven at 50 °C and 1 KPa for 12 h to obtain a constant weight to obtain the reaction intermediate ZIF-67.

[0051] Take 6g of 2-amino pyrazine and 9g of ZIF-67, dissolve into 300mL of tetrahydrofuran solution, ultrasonic for 10min to disperse uniformly, as solution C, then add solution C into 500mL three-necked flask, connect 100mL constant pressure dropping funnel, magnetic stirring, 24 snake-shaped condenser, tail gas receiving and processing device, stir and heat up at 70℃. Dissolve 3g of hexachlorocyclotriphosphazene in 70mL of tetrahydrofuran solution, stir at room temperature and normal pressure until clear and transparent, as solution D, then add solution D into constant pressure funnel, adjust the flow rate to drop for 30min, continue to stir for 16h to end the reaction, filter the precipitate, then wash with 20mL of tetrahydrofuran and 20mL of acetone alternately for three times, then dry in vacuum oven at 60℃ and 1KPa for 16h, get green powder flame retardant 13.56g, yield 75.3%.

[0052] Take 150g of epoxy resin E-44 as matrix, pour into 200mL beaker, and mechanically stir at 400r / min under open condition at 80℃. At the same time, take 35g of 4,4'-diaminodiphenyl methane as curing agent in 50mL beaker, and melt in 120℃ oven for 20min. Then, dissolve 3.75g of flame retardant prepared in this example in 30mL of acetone, disperse uniformly by ultrasonic treatment for 5min, pour into the epoxy resin system for further stirring. After 30min, the acetone in the epoxy system is completely volatilized, the melted curing agent is poured into the epoxy resin system, and the system is uniformly stirred for 1min, then the system is poured into the mold, and cured at 130℃ for 4h to obtain an epoxy resin composite material.

[0053] The obtained epoxy resin composite material is tested by limiting oxygen index (LOI), and the measured limiting oxygen index value is 27.8%. The vertical burning experiment (UL-94) is tested, and the obtained flame retardant grade is V-0 grade. Further, the cone calorimeter test is carried out, and the peak heat release rate is reduced by 37.7% compared with the pure epoxy system, the total heat release is reduced by 27.6% compared with the pure epoxy system, the carbon dioxide yield is reduced by 42%, and the carbon monoxide yield is reduced by 40%. The epoxy system is also tested for mechanical properties and ultraviolet diffuse reflectance, and the results show that the tensile strength of the epoxy composite system is not significantly different from that of the pure epoxy system, and the ultraviolet transmittance is reduced by 41%.

[0054] In summary, the invention includes but is not limited to the above examples, any equivalent replacement or partial improvement made within the spirit and principles of the invention will be considered within the protection scope of the invention.

Claims

1. A method for preparing an anti-aging cyclophosphonitrile metal framework structured nanoflame retardant, characterized in that: The method steps include: 2-Aminopyrazine and cobalt-based metal-organic framework ZIF-67 were dissolved in an organic solvent, heated to 60-70°C, and hexachlorocyclotriphosphazene solution was added. The mixture was heated and stirred under reflux for 12-18 h. After the reaction was completed, the precipitate was collected, washed, and vacuum dried to obtain an anti-aging cyclophosphazene metal framework structure nano flame retardant. The mass ratio of 2-aminopyrazine, ZIF-67 and hexachlorocyclotriphosphazene is 1:1~10:1~4.

2. The preparation method of the anti-aging cyclophosphonitrile metal framework structure nano flame retardant as described in claim 1, characterized in that: The mass ratio of 2-aminopyrazine, ZIF-67 and hexachlorocyclotriphosphazene is 1:2~6:2~3.

3. The preparation method of the anti-aging cyclophosphonitrile metal framework structure nano flame retardant as described in claim 1, characterized in that: The organic solvent is one or more of tetrahydrofuran, anhydrous acetonitrile, acetone, and dichloromethane; the solvent of the hexachlorocyclotriphosphazene solution is tetrahydrofuran.

4. The preparation method of the anti-aging cyclophosphonitrile metal framework structure nano flame retardant as described in claim 1, characterized in that: The hexachlorocyclotriphosphazene solution was added within 30 minutes.

5. The preparation method of the anti-aging cyclophosphonitrile metal framework structure nano flame retardant as described in claim 1, characterized in that: The stirring speed is 300~400 rpm.

6. The preparation method of the anti-aging cyclophosphonitrile metal framework structure nano flame retardant as described in claim 1, characterized in that: The drying temperature is 50~70℃, and the drying time is 8~16 h.

7. The preparation method of the anti-aging cyclophosphonitrile metal framework structure nano flame retardant as described in claim 1, characterized in that: The cobalt-based metal-organic framework ZIF-67 was prepared by the following method, the steps of which include: dissolving cobalt nitrate hexahydrate in solvent A to obtain a cobalt salt solution; dissolving 2-methylimidazole in solvent B to obtain a 2-methylimidazole solution; adding the 2-methylimidazole solution to the cobalt salt solution; allowing it to stand at 15~40℃ for 8~32h; after standing, centrifuging at 6000~12000 rad / min for 3~8min; washing with anhydrous ethanol; and drying at 50~70℃ for 8~16h to obtain ZIF-67.

8. The preparation method of the anti-aging cyclophosphonitrile metal framework structure nano flame retardant as described in claim 7, characterized in that: The molar ratio of cobalt nitrate hexahydrate to 2-methylimidazole is 1:4~10; The settling temperature should be 25~35℃; Centrifugation time is 4-6 minutes; Solvent A and solvent B are one or more of anhydrous methanol, anhydrous ethanol and water, respectively.

9. The preparation method of the anti-aging cyclophosphonitrile metal framework structure nano flame retardant as described in claim 7, characterized in that: The molar ratio of cobalt nitrate hexahydrate to 2-methylimidazole is 1:4~6.

10. An anti-aging cyclophosphonitrile metal framework structured nanoflame retardant, characterized in that: It is prepared by the method described in any one of claims 1 to 9.

11. The application of the anti-aging cyclophosphonitrile metal framework structure nanoflame retardant as described in claim 10, characterized in that: The flame retardant is used as a flame retardant in a polymer system.

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