A metal organic framework-based porous liquid functional flame retardant and preparation method thereof

Abstract

The present invention relates to a metal-organic framework-based porous liquid functional flame retardant and a preparation method thereof, and more particularly to a porous liquid functional flame retardant that combines flame retardancy, corrosion resistance, and mechanical reinforcement, and a preparation method thereof, belonging to the technical field of advanced functional materials. The present invention provides a metal-organic framework-based porous liquid functional flame retardant, wherein the hindered solvent component has low surface energy, hydrophobicity, and chemical inertness; and the functionally group-modified flame-retardant functionalized metal-organic framework has good chemical stability and dispersibility. Thus, the resulting composite material has improved flame retardancy, mechanical properties, hydrophobicity, and corrosion resistance.

Description

Technical Field

[0001] The present invention relates to a metal organic framework-based porous liquid functional flame retardant and a preparation method thereof, and in particular to a porous liquid functional flame retardant with flame retardancy, corrosion resistance and mechanical enhancement and a preparation method thereof, belonging to the technical field of advanced functional materials. Background Art

[0002] The application of flame retardants in polymer materials can effectively slow down the burning rate of the materials and improve their safety performance. The dispersion state of flame retardant fillers in polymers is one of the key factors that determine the comprehensive performance of composite materials. Good dispersion of fillers can not only significantly improve the flame retardant properties of composite materials, but also have a significant impact on their mechanical properties, thermal stability and processing properties. Currently, researchers have improved the compatibility of fillers with polymer chains through methods such as chemical modification and solvent assistance. Patent announcement number (CN118126385A) discloses a high-strength flame retardant PVC composite material and its preparation method. This patented technology first prepares positively charged whisker calcium carbonate, electrostatically self-assembles with negatively charged silica, and prepares microencapsulated fillers together with flame retardants, and then modifies the surface with gas-phase 2-butyl-undecanoic acid, and then fills with the ground modified PVC, and with the help of supercritical carbon dioxide, makes the calcium carbonate more evenly distributed, so as to achieve the purpose of enhancing the mechanical strength and flame retardant effect of the PVC composite material. Furthermore, Wang et al. (DOI:10.1021 / acsomega.2c01545) used a core-shell ZIF67@ZIF8 template and phytic acid (PA) as an etchant to prepare a core-shell phytic acid-modified bimetallic organic framework hybrid (PA-ZIF67@ZIF8). This PA-ZIF67@ZIF8 was further dispersed in acetone to prepare an epoxy composite. The flame retardant PA-ZIF67@ZIF8, rich in flame retardant elements and possessing a hierarchical porous structure, effectively promotes the catalytic carbonization and adsorption of pyrolytic volatiles. A mere 5 wt% addition of PA-ZIF67@ZIF8 imparted a limiting oxygen index of 29.3% to the epoxy composite, passing UL-94 V-0. Furthermore, the peak heat release rate, total heat release, and peak carbon monoxide release rate of the epoxy composite decreased by 42.2%, 33.0%, and 41.5%, respectively, compared to pure epoxy. However, these methods often face problems such as cumbersome processing and solvent waste, and achieving high dispersion of fillers remains a challenge. Therefore, designing highly dispersible and efficient flame-retardant fillers has important research significance and social value. Summary of the Invention

[0003] The purpose of the present invention is to solve the problems of serious agglomeration, low flame retardant efficiency, obvious mechanical damage to composite materials and single function of existing flame retardants, and to provide a metal organic framework-based porous liquid functional flame retardant and its preparation method.

[0004] The purpose of the present invention is achieved through the following technical solutions.

[0005] A metal organic framework-based porous liquid functional flame retardant, the porous liquid functional flame retardant comprising a flame retardant functionalized metal organic framework and a steric hindered solvent, wherein the flame retardant functionalized metal organic framework is dispersed in the steric hindered solvent;

[0006] The hindered solvent is poly(dimethylsiloxane), monoglycidyl ether end-capped, with an average molecular weight between 2000-30000;

[0007] The specific surface area of ​​the flame retardant functionalized metal organic framework is 400 m 2 / g or more, with an average pore size of 0.5nm-10.0nm;

[0008] The flame-retardant functionalized metal-organic framework preparation method comprises: mixing a metal-organic framework, a functional etchant, and a solvent A, performing ultrasonic dispersion, heating to react, naturally cooling to room temperature after the reaction, centrifuging, washing, and drying the product to obtain the flame-retardant functionalized metal-organic framework;

[0009] A method for preparing a metal organic framework-based porous liquid functional flame retardant, comprising the following steps:

[0010] The first step is to prepare a flame-retardant functionalized metal-organic framework, specifically: mixing the metal-organic framework, a functional etchant, and solvent A, ultrasonically dispersing them, heating them to react, naturally cooling them to room temperature after the reaction, centrifuging the product, washing them, and drying them to obtain a flame-retardant functionalized metal-organic framework;

[0011] The second step is to perform functional group modification on the flame retardant functionalized metal organic framework obtained in the first step, specifically, dispersing the flame retardant functionalized metal organic framework in solvent C, then adding a functional group modifier, a dehydrating agent, and a condensation activator, stirring at room temperature, and after the stirring is completed, centrifuging, washing, and drying in sequence to obtain a functional group-modified flame retardant functionalized metal organic framework;

[0012] In the third step, the functional group-modified flame-retardant functionalized metal organic framework obtained in the second step, toluene and steric solvent are mixed, heated and stirred to react, and dried after the reaction to obtain a metal organic framework-based porous liquid functional flame retardant.

[0013] In the first step, the metal organic framework is a carboxylic acid metal organic framework, such as UiOs and MILs, preferably UiO-66, UiO-67, UiO-66-NH2, MIL-45(Co), MIL-45(Fe), MOF-74(Ni) and MIL-53(Fe), with a particle size distribution between 10 nm and 50 μm;

[0014] The mass ratio of the metal organic framework to the functional etchant is 1:0.05-0.3;

[0015] The functional etchant is one of 3-phosphonopropionic acid, phenylphosphonic acid, phytic acid and phosphoric acid;

[0016] The mass of the solvent A is 50-500 times the mass of the metal organic framework;

[0017] The solvent A is at least one of tetrahydrofuran, acetonitrile, deionized water, and N,N-dimethylformamide;

[0018] The reaction temperature is 80-120°C and the reaction time is 2-6h;

[0019] The heating reaction is carried out in a stainless steel high-pressure reactor, and a blast oven is used for heating during the reaction;

[0020] When washing, first use solvent A for washing, and then use solvent B for washing, where solvent B is at least one of methanol, acetone, and ethanol;

[0021] When drying, vacuum drying is used, the drying temperature is 60-80°C, and the drying time is 10-12h;

[0022] During centrifugation, the speed is 6000-10000 rad / min and the centrifugation time is 3-5 min;

[0023] In the second step, the functional group modifying agent includes but is not limited to octa(4-aminophenyl)silsesquioxane, 1,2,3-triaminobenzene, 2,3,6,7,10,11-hexaaminotriphenyl hexahydrochloride, 2,3,6,7,10,11-hexahydroxytriphenyl, 2,3,4,4'-tetrahydroxybenzophenone and 1,3,5-trihydroxybenzene and other polyamino or polyhydroxy compounds;

[0024] The solvent C is at least one of tetrahydrofuran, acetonitrile, N,N-dimethylformamide and dichloromethane;

[0025] The mass of solvent C is 50-500 times the mass of the flame retardant functionalized metal organic framework;

[0026] The dehydrating agent is 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride;

[0027] The condensation activator is 4-(4-(dimethylamino)phenyl)pyridine;

[0028] The mass ratio of the flame retardant functionalized metal organic framework, the functional group modifier, the dehydrating agent, and the condensation activator is 1: (0.01-0.1): (0.001-0.02): (0.0012-0.024);

[0029] The stirring speed is 300-600 rad / min and the stirring time is 4-12h;

[0030] During centrifugation, centrifuge at a speed of 6000-10000 rad / min for 2-5 minutes;

[0031] The samples were washed twice with solvent C, deionized water, and toluene respectively;

[0032] The drying is carried out in a vacuum oven at a drying temperature of 80-100°C and a drying time of 10-12 hours;

[0033] In the third step, the hindered solvent is 3-20 times the mass of the functional group-modified flame retardant functionalized metal organic framework;

[0034] The mass ratio of the functional group-modified flame-retardant functionalized metal organic framework to toluene is 1:5-50;

[0035] When the reaction occurs, use an oil bath to heat at 100-110°C, reflux with stirring for 4-12 hours, then transfer to a heating table and stir at 80-90°C for 4-8 hours;

[0036] The drying is carried out in a vacuum oven at a drying temperature of 80-90°C and a drying time of 24-48 hours.

[0037] Beneficial effects

[0038] 1. The flame retardant functional metal organic framework functional porous guest of the present invention is an important component in the preparation of porous liquids. The specific surface area of ​​this type of material is 400m 2 / g or more, with an average pore size distribution between 0.5 nm and 10.0 nm, and having good flame retardant properties and a high specific surface area; the present invention intends to protect a method for modifying functional groups of a flame-retardant functionalized metal-organic framework, that is, the functional group modifier includes but is not limited to polyamino or polyhydroxy compounds such as octa(4-aminophenyl)silsesquioxane, 1,2,3-triaminobenzene, 2,3,6,7,10,11-hexaaminotriphenyl hexahydrochloride, 2,3,6,7,10,11-hexahydroxytriphenyl, 2,3,4,4'-tetrahydroxybenzophenone and 1,3,5-trihydroxybenzene;

[0039] 2. The present invention provides a metal organic framework-based porous liquid functional flame retardant, which has an initial decomposition temperature greater than 300°C and excellent thermal stability, meeting the processing technology requirements of materials such as polyurea, polyurethane, polycarbonate and polypropylene.

[0040] 3. The present invention provides a metal-organic framework-based porous liquid functional flame retardant, in which the functional group-modified flame-retardant functionalized metal-organic framework in its components can react with steric solvents and produce good solid-liquid interaction, greatly improving its dispersion state and compatibility in steric solvents. It can be left standing at 25°C for 6 months without sedimentation and stratification, and has excellent storage stability.

[0041] 4. The present invention provides a metal-organic framework-based porous liquid functional flame retardant, in which the functional group-modified flame-retardant functionalized metal-organic framework in its components has excellent dispersibility, can be evenly dispersed in polymer composites, and enhance the mechanical properties of the composites.

[0042] 5. The present invention provides a metal-organic framework-based porous liquid functional flame retardant, in which the flame-retardant functionalized metal-organic framework in its components has a rich pore structure, which is conducive to the capture of smoke particles; and the rich flame-retardant elements in its structure and the more active sites exposed by the high specific surface area are conducive to catalyzing the carbonization of the polymer matrix, showing excellent flame retardant and smoke suppression effects.

[0043] 6. The present invention provides a metal-organic framework-based porous liquid functional flame retardant, in which the steric hindered solvent has low surface energy, hydrophobicity and chemical inertness; at the same time, the functional group-modified flame-retardant functionalized metal-organic framework has good chemical stability, so the hydrophobicity and corrosion resistance of the prepared composite material are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a transmission electron micrograph of the flame-retardant functionalized metal-organic framework prepared in Example 1;

[0045] Figure 2 This is a transmission electron micrograph of the metal organic framework-based porous liquid functional flame retardant prepared in Example 1;

[0046] Figure 3 This is a digital photograph of the metal organic framework-based porous liquid functional flame retardant prepared in Example 1 after standing at 25° C. for 6 months;

[0047] Figure 4 This is a scanning electron microscope image of the brittle fracture cross-section of the polyurea composite material prepared in Example 1;

[0048] Figure 5 This is a scanning electron micrograph of the functional group-modified flame-retardant functionalized metal-organic framework prepared in Example 2;

[0049] Figure 6 This is a digital photo of the metal organic framework-based porous liquid functional flame retardant prepared in Example 2 after being left at 25° C. for 6 months. DETAILED DESCRIPTION

[0050] The following examples are given in conjunction with the experimental results of the present invention to further illustrate the present invention:

[0051] A method for preparing a metal organic framework-based porous liquid functional flame retardant, comprising the following steps:

[0052] Step 1: weighing a metal organic framework and a functional etchant in a mass ratio of 1: (0.05-0.3), adding the weighed metal organic framework to a certain mass of solvent A, and ultrasonically dispersing it until it is uniformly dispersed to obtain a suspension A; adding the weighed functional etchant to the suspension A, and ultrasonically dispersing it until the functional etchant is dissolved to obtain a suspension B;

[0053] Step 2: Transfer the suspension B obtained in step 1 to a stainless steel autoclave and heat it in a forced air oven at 80-120°C for 2-6 hours to stop the reaction. Cool the stainless steel autoclave to room temperature and then open it. Transfer the product to a centrifuge tube for centrifugation at a speed of 6000-10000 rad / min for 3-5 minutes. Wash it 1-3 times with solvent A and then 1-2 times with solvent B. Then, dry the product in a vacuum oven at 60-80°C for 10-12 hours to obtain a flame-retardant functionalized metal-organic framework.

[0054] Step 3: Weigh the flame-retardant functionalized metal-organic framework (MOF) obtained in Step 2, a functional group modifier, a dehydrating agent (1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride), and a condensation activator (4-(4-(dimethylamino)phenylvinyl)pyridine) in a mass ratio of 1:(0.01-0.1):(0.001-0.02):(0.0012-0.024). Add the MOF to a predetermined mass of solvent C and sonicate until uniformly dispersed. Then, add the functional group modifier, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and 4-(4-(dimethylamino)phenylvinyl)pyridine in that order. Then, switch to a stirring process at a speed of 300-600 rad / min. After stirring at room temperature for 4-12 hours, the product was transferred to a centrifuge tube and centrifuged at 6000-10000 rad / min for 2-5 minutes. The product was washed twice with solvent C, deionized water, and toluene, respectively. The product was then dried in a vacuum oven at 80-100°C for 10-12 hours to obtain a functional group-modified flame-retardant metal-organic framework.

[0055] Step 4. Weigh the functional group-modified flame-retardant functionalized metal organic framework obtained in step 3 and toluene at a mass ratio of 1:(5-50), add the functional group-modified flame-retardant functionalized metal organic framework to toluene, and sonicate until uniformly dispersed to obtain suspension C. Add a certain amount of steric hindered solvent to suspension C, transfer to an oil bath, reflux and stir at 100-110° C. for 4-12 hours, then transfer to a heating table and stir at 80-90° C. for 4-8 hours, and then transfer to a vacuum oven and vacuum dry at 80-90° C. for 24-48 hours to obtain a metal organic framework-based porous liquid functional flame retardant.

[0056] Example 1

[0057] A method for preparing a metal organic framework-based porous liquid functional flame retardant, comprising the following steps:

[0058] Step 1: Weigh 5.0 g of the carboxylic acid metal-organic framework UiO-66-NH2 and 0.5 g of the functional etchant 3-phosphonopropionic acid in a mass ratio of 1:0.1, add the weighed UiO-66-NH2 to 300.0 g of deionized water, and sonicate until uniformly dispersed to obtain suspension A. Add the weighed 3-phosphonopropionic acid to suspension A and sonicate until the 3-phosphonopropionic acid is dissolved to obtain suspension B.

[0059] Step 2: Transfer the suspension B obtained in step 1 to a stainless steel autoclave and heat it in a forced air oven at 100°C for 4 hours to stop the reaction. The stainless steel autoclave is cooled to room temperature and then opened. The product is transferred to a centrifuge tube and centrifuged at 8000 rad / min for 3 minutes. The tube is washed twice with deionized water and then twice with ethanol. The product is then dried in a vacuum oven at 80°C for 12 hours to obtain a flame-retardant functionalized metal-organic framework.

[0060] Step 3: Weigh 3.0 g of the flame-retardant functionalized metal-organic framework (MOF) obtained in Step 2, 0.15 g of the functional group modifier octa(4-aminophenyl)silsesquioxane, 0.015 g of the dehydrating agent 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and 0.021 g of the condensation activator 4-(4-(dimethylamino)phenylvinyl)pyridine in a mass ratio of 1:0.05:0.005:0.007. Add the MOF to 200 g of tetrahydrofuran and sonicate until uniformly dispersed. Then, add octa(4-aminophenyl)silsesquioxane, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and 4-(4-(dimethylamino)phenylvinyl)pyridine in that order. Then, switch to a stirring process at a speed of 350 rad / min. After stirring at room temperature for 8 hours, the product was transferred to a centrifuge tube and centrifuged at 6000 rad / min for 2 minutes. It was then washed twice with tetrahydrofuran, deionized water, and toluene. The product was then dried in a vacuum oven at 80°C for 12 hours to obtain a flame-retardant metal-organic framework modified with functional groups.

[0061] Step 4: Weigh 2.0 g of the functional group-modified flame-retardant functionalized metal-organic framework obtained in Step 3 and 20.0 g of toluene at a mass ratio of 1:10, add the functional group-modified flame-retardant functionalized metal-organic framework to the toluene, and sonicate until uniformly dispersed to obtain a suspension C. 10.0 g of poly(dimethylsiloxane) capped with monoglycidyl ether (average molecular weight of 5000) is added to the suspension C, transferred to an oil bath, refluxed at 100°C with stirring for 6 hours, then transferred to a heating plate and stirred at 80°C for 4 hours, and then transferred to a vacuum oven and vacuum dried at 80°C for 36 hours to obtain a metal-organic framework-based porous liquid functional flame retardant.

[0062] The flame-retardant functionalized metal organic framework prepared above was characterized under a transmission electron microscope (TEM) using an HT7700 transmission electron microscope (Hitachi, Germany). The sample was observed under a 120 kV electron source. The sample was prepared by ultrasonically dispersing it in acetone, then dripping it onto a supported carbon film, and then drying it in air. The resulting TEM image is shown in Figure 2. Figure 1 .Depend on Figure 1 It can be seen that the surface of the flame-retardant functionalized metal-organic framework becomes rough, proving that the functional etchant successfully etches UiO-66-NH2.

[0063] The prepared metal organic framework-based porous liquid functional flame retardant was characterized under a transmission electron microscope (TEM) using a HT7700 transmission electron microscope (Hitachi, Germany). The sample was observed under a 120 kV electron source. The sample was prepared by dropping it onto a supporting carbon film and then drying it in air. The resulting TEM image is shown in Figure 2. Figure 2.Depend on Figure 2 It can be seen that the flame-retardant functionalized metal-organic framework nanoparticles are tightly wrapped by poly(dimethylsiloxane), monoglycidyl ether end-capping (average molecular weight of 5000), and the flame-retardant functionalized metal-organic framework is self-assembled into a continuous matrix through poly(dimethylsiloxane), monoglycidyl ether end-capping (average molecular weight of 5000), which is the key to ensuring the fluidity of the metal-organic framework-based porous liquid functional flame retardant;

[0064] The stability of the metal organic framework-based porous liquid functional flame retardant prepared above was characterized. The test method was to place the sample in an isotope bottle, and after standing horizontally at 25°C for 6 months, tilt the isotope bottle to observe whether there was precipitation at the bottom. The digital photo obtained is as follows Figure 3 .Depend on Figure 3 It can be seen that the metal organic framework-based porous liquid functional flame retardant did not settle after standing for 6 months, proving that it has good storage stability;

[0065] The metal organic framework-based porous liquid functional flame retardant in Example 1 was applied to polyurea to prepare a polyurea composite material. When added at a level of 10 wt%, the composite material achieved a limiting oxygen index of 27.8%, a vertical combustion rating of UL-94 V-0, and a peak heat release rate, total heat release, and total smoke release relative to pure polyurea by 45.2%, 30.3%, and 45.9%, respectively. The breaking strength and elongation at break of the polyurea composite material increased by 19.2% and 14.7%, respectively, relative to pure polyurea. After immersion in corrosive media (3.5 wt% aqueous hydrogen chloride solution, 3.5 wt% aqueous sodium hydroxide solution, and 3.5 wt% aqueous sodium chloride solution) at 25°C for two months, the weight loss percentage (WL%) of the polyurea composite material was less than 1.0%, and there was no significant change in appearance.

[0066] The weight loss percentage (WL(%)) of the polyurea composite sample was calculated according to the following formula:

[0067]

[0068] where m0 and m1 are the original or final weight of the polyurea composite sample before and after the corrosion test, respectively.

[0069] The brittle fracture cross-section of the polyurea composite material prepared above was characterized under a scanning electron microscope using a Hitachi S4800 field emission scanning electron microscope (Hitachi, Japan). The test was conducted at an accelerating voltage of 15 kV and the sample was gold-sprayed. The obtained scanning electron microscope images are shown in FIG. Figure 4 .Depend on Figure 4 It can be seen that the flame retardant filler is evenly distributed in the polyurea matrix without obvious agglomeration.

[0070] Example 2

[0071] A method for preparing a metal organic framework-based porous liquid functional flame retardant, comprising the following steps:

[0072] Step 1. Weigh 20.0 g of the metal organic framework MIL-53(Fe) and 3.0 g of the functional etchant phenylphosphonic acid at a mass ratio of 1:0.15, add the weighed MIL-53(Fe) to 2.0 kg of N,N-dimethylformamide, and ultrasonicate until it is uniformly dispersed to obtain a suspension A; add the weighed phenylphosphonic acid to the suspension A, and ultrasonicate until the phenylphosphonic acid is dissolved to obtain a suspension B;

[0073] Step 2: Transfer the suspension B obtained in step 1 to a stainless steel autoclave and heat it in a forced air oven at 110°C for 6 hours to stop the reaction. The stainless steel autoclave is cooled to room temperature and then opened. The product is transferred to a centrifuge tube and centrifuged at 7000 rad / min for 5 minutes. The product is washed twice with N,N-dimethylformamide and then twice with methanol. The product is then dried in a vacuum oven at 80°C for 12 hours to obtain a flame-retardant functionalized metal-organic framework.

[0074] Step 3: Weigh 15.0 g of the flame-retardant functionalized metal-organic framework (MOF) obtained in Step 2, 1.2 g of the functional group modifier 1,2,3-triaminobenzene, 0.135 g of the dehydrating agent 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and 0.15 g of the condensation activator 4-(4-(dimethylamino)phenylvinyl)pyridine in a mass ratio of 1:0.08:0.009:0.01. Add the MOF to 1.5 kg of acetonitrile and sonicate until uniformly dispersed. Then, add 1,2,3-triaminobenzene, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and 4-(4-(dimethylamino)phenylvinyl)pyridine in that order. Then, switch to a stirring process at a speed of 500 rad / min. After stirring at room temperature for 12 hours, the product was transferred to a centrifuge tube and centrifuged at 8000 rad / min for 3 minutes. The product was then washed twice with acetonitrile, deionized water, and toluene. The product was then dried in a vacuum oven at 80°C for 12 hours to obtain a flame-retardant metal-organic framework modified with functional groups.

[0075] Step 4: Weigh 10.0 g of the functional group-modified flame-retardant functionalized metal-organic framework obtained in Step 3 and 300.0 g of toluene at a mass ratio of 1:30, add the functional group-modified flame-retardant functionalized metal-organic framework to the toluene, and ultrasonicate until uniformly dispersed to obtain a suspension C. 100.0 g of a hindered solvent, poly(dimethylsiloxane), capped with monoglycidyl ether (average molecular weight of 10,000), is added to the suspension C, transferred to an oil bath, refluxed and stirred at 105° C. for 10 hours, then transferred to a heating plate and stirred at 80° C. for 8 hours, and then transferred to a vacuum oven and vacuum dried at 80° C. for 40 hours to obtain a metal-organic framework-based porous liquid functional flame retardant.

[0076] The functional group-modified flame retardant functionalized metal organic framework prepared above was characterized under a scanning electron microscope using a Hitachi S4800 field emission scanning electron microscope (Hitachi, Japan). The test was conducted at an accelerating voltage of 15 kV and the sample was gold-sprayed. The obtained scanning electron microscope images are shown in Figure 2. Figure 5 .Depend on Figure 5 It can be seen that the surface of the flame-retardant functionalized metal organic framework modified with functional groups becomes rough, proving that the functional group modifier has successfully achieved chemical modification of MIL-53(Fe).

[0077] The stability of the metal organic framework-based porous liquid functional flame retardant prepared above was characterized. The test method was to place the sample in an isotope bottle, and after standing horizontally at 25°C for 6 months, tilt the isotope bottle to observe whether there was precipitation at the bottom. The digital photo obtained is as follows Figure 6 .Depend on Figure 6 It can be seen that the metal organic framework-based porous liquid functional flame retardant did not settle after standing for 6 months, proving that it has good storage stability;

[0078] The metal organic framework-based porous liquid functional flame retardant in this embodiment was applied to polyurethane to prepare a polyurethane composite. When added at 8wt%, the composite's limiting oxygen index reached 28.2%, its vertical combustion rating reached UL-94 V-0, and its peak heat release rate, total heat release, and total smoke release decreased by 49.3%, 30.2%, and 40.9%, respectively, compared to pure polyurethane. The breaking strength and elongation at break of the polyurethane composite increased by 17.1% and 12.6%, respectively, compared to pure polyurethane. After being immersed in corrosive media (3.5wt% aqueous hydrogen chloride solution, 3.5wt% aqueous sodium hydroxide solution, and 3.5wt% aqueous sodium chloride solution) at 25°C for two months, the weight loss percentage (WL(%)) of the polyurethane composite was less than 1.3%, and there was no significant change in appearance.

[0079] The weight loss percentage (WL(%)) of the polyurethane composite sample was calculated according to the following formula:

[0080]

[0081] where m0 and m1 are the original or final weights of the polyurethane composite samples before and after the corrosion test, respectively.

[0082] Example 3

[0083] A method for preparing a metal organic framework-based porous liquid functional flame retardant, comprising the following steps:

[0084] Step 1. Weigh 20.0 g of the metal organic framework MIL-101(Fe) and 4.0 g of the functional etchant 3-phosphonopropionic acid in a mass ratio of 1:0.2, add the weighed MIL-101(Fe) to 5.0 kg of acetonitrile, and ultrasonicate until it is uniformly dispersed to obtain a suspension A; add the weighed 3-phosphonopropionic acid to the suspension A, and ultrasonicate until the 3-phosphonopropionic acid is dissolved to obtain a suspension B;

[0085] Step 2: Transfer the suspension B obtained in step 1 to a stainless steel autoclave and heat it in a forced air oven at 80°C for 5 hours to stop the reaction. The stainless steel autoclave is cooled to room temperature and then opened. The product is transferred to a centrifuge tube and centrifuged at 9000 rad / min for 3 minutes. The product is washed twice with acetonitrile and once with acetone. The product is then dried in a vacuum oven at 80°C for 12 hours to obtain a flame-retardant functionalized metal-organic framework.

[0086] Step 3: Weigh 15.0 g of the flame-retardant functionalized metal-organic framework (MOF) obtained in Step 2, 0.75 g of the functional group modifier 2,3,6,7,10,11-hexaminothiazolidine hydrochloride, 0.075 g of the dehydrating agent 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and 0.12 g of the condensation activator 4-(4-(dimethylamino)phenyl)pyridine in a mass ratio of 1:0.05:0.005:0.008. Add the MOF to 3.0 kg of N,N-dimethylformamide and sonicate until uniformly dispersed. Then, add 2,3,6,7,10,11-hexaminothiazolidine hydrochloride, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and 4-(4-(dimethylamino)phenyl)pyridine in that order. Then, switch to stirring at a speed of 600 rad / min. After stirring at room temperature for 11 hours, the product was transferred to a centrifuge tube and centrifuged at 10,000 rad / min for 2 minutes. The product was washed twice with N,N-dimethylformamide, deionized water, and toluene. The product was then dried in a vacuum oven at 80°C for 12 hours to obtain a functionalized flame-retardant metal-organic framework.

[0087] Step 4: Weigh 10.0 g of the functional group-modified flame-retardant functionalized metal-organic framework obtained in Step 3 and 400.0 g of toluene at a mass ratio of 1:40, add the functional group-modified flame-retardant functionalized metal-organic framework to the toluene, and sonicate until uniformly dispersed to obtain a suspension C. 40.0 g of a hindered solvent, poly(dimethylsiloxane), capped with monoglycidyl ether (average molecular weight of 15,000), is added to the suspension C, transferred to an oil bath, refluxed at 110° C. with stirring for 12 hours, then transferred to a heating plate and stirred at 80° C. for 8 hours, and then transferred to a vacuum oven and vacuum-dried at 80° C. for 24 hours to obtain a metal-organic framework-based porous liquid functional flame retardant.

[0088] The metal organic framework-based porous liquid functional flame retardant in this embodiment was applied to polypropylene to prepare a polypropylene composite material. When added in an amount of 12wt%, the limiting oxygen index of the composite material reached 28.8%, the vertical combustion rating reached UL-94V-1, and the peak heat release rate, total heat release, and total smoke release decreased by 50.3%, 36.2%, and 46.2% respectively relative to pure polypropylene. The breaking strength and elongation at break of the polypropylene composite material increased by 22.1% and 16.6% respectively relative to pure polypropylene. After the polypropylene composite material was immersed in a corrosive medium (3.5wt% hydrogen chloride aqueous solution, 3.5wt% sodium hydroxide aqueous solution, and 3.5wt% sodium chloride aqueous solution) at 25°C for 2 months, its weight loss percentage (WL(%)) was less than 1.8%, and there was no significant change in appearance.

[0089] The weight loss percentage (WL(%)) of the polypropylene composite sample was calculated according to the following formula:

[0090]

[0091] where m0 and m1 are the original or final weights of the polypropylene composite samples before and after the corrosion resistance test, respectively.

[0092] Example 4

[0093] A method for preparing a metal organic framework-based porous liquid functional flame retardant, comprising the following steps:

[0094] Step 1: Weigh 30.0 g of the metal organic framework UiO-66 and 7.5 g of the functional etchant phenylphosphonic acid at a mass ratio of 1:0.25, add the weighed UiO-66 to 6.0 kg of deionized water, and sonicate until it is uniformly dispersed to obtain suspension A; add the weighed phenylphosphonic acid to suspension A, and sonicate until the phenylphosphonic acid is dissolved to obtain suspension B;

[0095] Step 2: Transfer the suspension B obtained in step 1 to a stainless steel autoclave and heat it in a forced air oven at 105°C for 3 hours to stop the reaction. The stainless steel autoclave is cooled to room temperature and then opened. The product is transferred to a centrifuge tube and centrifuged at 10,000 rad / min for 3 minutes. The tube is washed twice with deionized water and twice with ethanol. The product is then dried in a vacuum oven at 80°C for 12 hours to obtain a flame-retardant functionalized metal-organic framework.

[0096] Step 3: Weigh 25.0 g of the flame-retardant functionalized metal-organic framework (MOF) obtained in Step 2, 2.5 g of the functional group modifier 2,3,6,7,10,11-hexahydroxytriphenylene glycol (2,3,6,7,10,11-hexahydroxytriphenylene glycol), 0.25 g of the dehydrating agent 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and 0.3 g of the condensation activator 4-(4-(dimethylamino)phenylvinyl)pyridine in a mass ratio of 1:0.1:0.01:0.012. Add the MOF to 7.5 kg of tetrahydrofuran and sonicate until uniformly dispersed. Then, add 2,3,6,7,10,11-hexahydroxytriphenylene glycol, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and 4-(4-(dimethylamino)phenylvinyl)pyridine in that order. Then, switch to stirring at a speed of 400 rad / min. After stirring at room temperature for 10 hours, the product was transferred to a centrifuge tube and centrifuged at 6000 rad / min for 2 minutes. The product was then washed twice with tetrahydrofuran, deionized water, and toluene. The product was then dried in a vacuum oven at 90°C for 12 hours to obtain a flame-retardant metal-organic framework modified with functional groups.

[0097] Step 4: Weigh 20.0 g of the functional group-modified flame-retardant functionalized metal-organic framework obtained in Step 3 and 500.0 g of toluene at a mass ratio of 1:25, add the functional group-modified flame-retardant functionalized metal-organic framework to the toluene, and sonicate until uniformly dispersed to obtain a suspension C. 160.0 g of a hindered solvent, poly(dimethylsiloxane), capped with monoglycidyl ether (average molecular weight of 20,000), is added to the suspension C, transferred to an oil bath, refluxed and stirred at 105° C. for 6 h, then transferred to a heating plate and stirred at 80° C. for 8 h, and then transferred to a vacuum oven and vacuum-dried at 80° C. for 24 h to obtain a metal-organic framework-based porous liquid functional flame retardant.

[0098] The metal-organic framework-based porous liquid functional flame retardant in this embodiment was applied to polycarbonate to prepare a polycarbonate composite. When added at 7 wt%, the composite's limiting oxygen index reached 29.3%, its vertical burning rating reached UL-94 V-0, and its peak heat release rate, total heat release, and total smoke release decreased by 52.3%, 38.2%, and 50.3%, respectively, relative to pure polycarbonate. The polycarbonate composite's breaking strength and elongation at break increased by 12.1% and 20.6%, respectively, relative to pure polycarbonate. After immersion in corrosive media (3.5 wt% aqueous hydrogen chloride solution, 3.5 wt% aqueous sodium hydroxide solution, and 3.5 wt% aqueous sodium chloride solution) at 25°C for two months, the polycarbonate composite's weight loss percentage (WL%) was less than 1.5%, with no significant change in appearance.

[0099] The weight loss percentage (WL(%)) of the polycarbonate composite sample was calculated according to the following formula:

[0100]

[0101] where m0 and m1 are the original or final weights of the polycarbonate composite samples before and after the corrosion test, respectively.

[0102] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A metal organic framework-based porous liquid functional flame retardant, characterized by: The porous liquid functional flame retardant comprises a functional group-modified flame retardant functionalized metal organic framework and a steric hindrance solvent, wherein the functional group-modified flame retardant functionalized metal organic framework is dispersed in the steric hindrance solvent; The hindered solvent is poly(dimethylsiloxane), monoglycidyl ether end-capped; The preparation method of the metal organic framework-based porous liquid functional flame retardant comprises the following steps: In the first step, the metal organic framework, functional etchant and solvent A are mixed, ultrasonically dispersed, heated to react, and naturally cooled to room temperature after the reaction is completed. The product is centrifuged, washed and dried to obtain a flame retardant functionalized metal organic framework; In the second step, the flame-retardant functionalized metal-organic framework obtained in the first step is dispersed in solvent C, and then a functional group modifier, a dehydrating agent, and a condensation activator are added, and stirred at room temperature. After the stirring is completed, centrifugation, washing, and drying are performed in sequence to obtain a functional group-modified flame-retardant functionalized metal-organic framework; In the third step, the flame-retardant functionalized metal organic framework modified with functional groups obtained in the second step, toluene and a hindered solvent are mixed, heated and stirred to react, and dried after the reaction to obtain a metal organic framework-based porous liquid functional flame retardant; The metal-organic framework is a carboxylic acid metal-organic framework; The mass ratio of the metal organic framework to the functional etchant is 1:0.05-0.3; The functional etchant is one of 3-phosphonopropionic acid, phenylphosphonic acid, phytic acid and phosphoric acid; In the second step, the functional group modifier is one of octa(4-aminophenyl)silsesquioxane, 1,2,3-triaminobenzene, 2,3,6,7,10,11-hexaaminotriphenyl hexahydrochloride, 2,3,6,7,10,11-hexahydroxytriphenyl, 2,3,4,4'-tetrahydroxybenzophenone and 1,3,5-trihydroxybenzene.

2. The metal organic framework-based porous liquid functional flame retardant according to claim 1, characterized in that: The average molecular weight of the hindered solvent is 2000-30000.

3. The metal organic framework-based porous liquid functional flame retardant according to claim 1, characterized in that: The flame retardant functionalized metal organic framework has a specific surface area of ​​400 m 2 / g or above, and the average pore diameter is 0.5nm-10.0nm.

4. The metal organic framework-based porous liquid functional flame retardant according to claim 1, characterized in that: In the first step, the mass of solvent A is 50-500 times the mass of the metal organic framework; The solvent A is at least one of tetrahydrofuran, acetonitrile, deionized water, and N,N-dimethylformamide; The reaction temperature is 80-120°C and the reaction time is 2-6h; The heating reaction is carried out in a stainless steel high-pressure reactor, and a blast oven is used for heating during the reaction; When washing, first use solvent A for washing, and then use solvent B for washing, where solvent B is at least one of methanol, acetone, and ethanol; When drying, vacuum drying is used, the drying temperature is 60-80 ℃, and the drying time is 10-12h; The rotation speed during centrifugation is 6000-10000 rad / min, and the centrifugation time is 3-5 minutes.

5. A method for preparing the metal organic framework-based porous liquid functional flame retardant according to claim 1, characterized in that the steps include: In the first step, the metal organic framework, functional etchant and solvent A are mixed, ultrasonically dispersed, heated to react, and naturally cooled to room temperature after the reaction is completed. The product is centrifuged, washed and dried to obtain a flame retardant functionalized metal organic framework; In the second step, the flame-retardant functionalized metal-organic framework obtained in the first step is dispersed in solvent C, and then a functional group modifier, a dehydrating agent, and a condensation activator are added, and stirred at room temperature. After the stirring is completed, centrifugation, washing, and drying are performed in sequence to obtain a functional group-modified flame-retardant functionalized metal-organic framework; In the third step, the functional group-modified flame-retardant functionalized metal organic framework obtained in the second step, toluene and steric solvent are mixed, heated and stirred to react, and dried after the reaction to obtain a metal organic framework-based porous liquid functional flame retardant.

6. The method for preparing a metal organic framework-based porous liquid functional flame retardant according to claim 5, characterized in that: In the first step, the metal organic framework is a carboxylic acid metal organic framework; The mass ratio of the metal organic framework to the functional etchant is 1:0.05-0.3; The functional etchant is one of 3-phosphonopropionic acid, phenylphosphonic acid, phytic acid and phosphoric acid; The mass of the solvent A is 50-500 times the mass of the metal organic framework; The solvent A is at least one of tetrahydrofuran, acetonitrile, deionized water, and N,N-dimethylformamide; The reaction temperature is 80-120°C and the reaction time is 2-6h; The heating reaction is carried out in a stainless steel high-pressure reactor, and a blast oven is used for heating during the reaction; When washing, first use solvent A for washing, and then use solvent B for washing, where solvent B is at least one of methanol, acetone, and ethanol; When drying, vacuum drying is used, the drying temperature is 60-80 ℃, and the drying time is 10-12h; The rotation speed during centrifugation is 6000-10000 rad / min, and the centrifugation time is 3-5 minutes.

7. The method for preparing a metal organic framework-based porous liquid functional flame retardant according to claim 6, characterized in that: The carboxylic acid metal organic framework is UiO-66, UiO-67, UiO-66-NH2, MIL-45(Co), MIL-45(Fe), MOF-74(Ni) or MIL-53(Fe), and its particle size distribution is between 10 nm and 50 μm.

8. The method for preparing a metal organic framework-based porous liquid functional flame retardant according to claim 5 or 6, characterized in that: In the second step, the functional group modifier is one of octa(4-aminophenyl)silsesquioxane, 1,2,3-triaminobenzene, 2,3,6,7,10,11-hexaaminotriphenyl hexahydrochloride, 2,3,6,7,10,11-hexahydroxytriphenyl, 2,3,4,4'-tetrahydroxybenzophenone and 1,3,5-trihydroxybenzene; The solvent C is at least one of tetrahydrofuran, acetonitrile, N,N-dimethylformamide and dichloromethane; The mass of solvent C is 50-500 times the mass of the flame retardant functionalized metal organic framework; The dehydrating agent is 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride; The condensation activator was 4-(4-(dimethylamino)phenyl)pyridine; The mass ratio of the flame retardant functionalized metal organic framework, functional group modifier, dehydrating agent, and condensation activator is 1: (0.01-0.1): (0.001-0.02): (0.0012-0.024); The stirring speed is 300-600 rad / min and the stirring time is 4-12h; During centrifugation, centrifuge at a speed of 6000-10000 rad / min for 2-5 minutes; The samples were washed twice with solvent C, deionized water, and toluene respectively; The drying is carried out in a vacuum oven at a drying temperature of 80-100°C and a drying time of 10-12 hours.

9. The method for preparing a metal organic framework-based porous liquid functional flame retardant according to claim 5, characterized in that: In the third step, the hindered solvent is 3-20 times the mass of the functional group-modified flame retardant functionalized metal organic framework; The mass ratio of the functional group-modified flame-retardant functionalized metal organic framework to toluene is 1:5-50; When the reaction occurs, use an oil bath to heat at 100-110°C, reflux and stir for 4-12 hours, then transfer to a heating plate and stir at 80-90°C for 4-8 hours; The drying is carried out in a vacuum oven at a drying temperature of 80-90°C and a drying time of 24-48 hours.

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