A flame retardant with methyl orange adsorption function and its preparation method and application

Abstract

The invention discloses a flame retardant with a function of absorbing methyl orange, belongs to the technical field of chemical materials, and the structural formula of the flame retardant is as follows:; wherein, the preparation method of the flame retardant comprises the following specific steps: after hexachlorocyclotriphosphazene and 1,5-naphthalenediamine are added to a solvent for dissolution, triethylamine is added for reflux reaction for 12-48h, and precipitation, washing and drying are obtained by filtering. The present invention improves the carbonization of phosphazene derivatives in polymer materials by a nucleophilic substitution reaction between a substance containing a condensed aromatic hydrocarbon structure and cyclophosphazene, thereby achieving the purpose of condensed phase flame retardancy, and the amine groups in the raw materials respectively cause the difference in spatial structure on two different benzene rings, so that its final flame retardant effect is more excellent, and has a good adsorption capacity, which can be applied in dye wastewater treatment.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical materials, and in particular relates to a flame retardant with the function of absorbing methyl orange, and a preparation method and application thereof. Background Art

[0002] With the development of society and the improvement of industrial level, all walks of life pay more and more attention to the combustion safety of building materials and products, so flame retardants are emerging in the market. However, the flame retardants in the existing technology have problems such as instability, excessive dosage and unsafety.

[0003] Phosphazene is a type of compound composed of alternating phosphorus and nitrogen elements with a stable phosphorus-nitrogen skeleton structure. Its unique phosphorus-nitrogen hybrid structure and high phosphorus and nitrogen content give it good thermal stability and flame retardancy. Phosphazene is considered to be a second-generation phosphorus-nitrogen intumescent flame retardant because of its advantages such as being halogen-free, low smoke production during combustion, high flame retardant efficiency, and no production of toxic and corrosive gases. Phosphazene compounds have undergone hundreds of years of research and development since they were synthesized. In the United States, they have been used in a wide range of fields such as military materials. They have also been applied in various fields in China, especially in the field of flame retardancy. However, the domestic market for phosphazene flame retardants is limited.

[0004] Therefore, it is an urgent problem for those skilled in the art to provide a stable, safe and efficient phosphorus-based flame retardant that does not require excessive addition. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a flame retardant with the function of adsorbing methyl orange, and a preparation method and application thereof.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A flame retardant having the function of absorbing methyl orange, the structural formula of the flame retardant is as follows:

[0008] .

[0009] Preferably, the flame retardant is prepared from hexachlorocyclotriphosphazene and 1,5-naphthalenediamine.

[0010] Preferably, the molar ratio of the hexachlorocyclotriphosphazene to the 1,5-naphthalenediamine is 1-5:1-10.

[0011] A method for preparing a flame retardant having the function of absorbing methyl orange comprises the following specific steps:

[0012] After adding hexachlorocyclotriphosphazene and 1,5-naphthalenediamine into a solvent and dissolving them, triethylamine is added and refluxed to react, and after the reaction is completed, a precipitate is filtered, washed and dried to obtain a flame retardant having the function of absorbing methyl orange.

[0013] The specific process route is as follows:

[0014] .

[0015] Preferably, the molar ratio of the hexachlorocyclotriphosphazene to the triethylamine is 1-5:1-30.

[0016] Preferably, the solvent is tetrahydrofuran or toluene.

[0017] Preferably, the solvent is added in an amount sufficient to dissolve the hexachlorocyclotriphosphazene and the 1,5-naphthalenediamine.

[0018] Preferably, the reaction time is 12-48 hours.

[0019] Preferably, the reflux reaction is carried out under a nitrogen atmosphere.

[0020] The present invention uses condensed ring aromatic hydrocarbon amino compounds and hexachlorocyclotriphosphazene to synthesize cyclotriphosphazene. The presence of benzene ring and nitrogen element is beneficial to improving the flame retardant efficiency of cyclotriphosphazene, which helps to improve the flame retardant performance and also has a good treatment effect in sewage treatment.

[0021] Use of the flame retardant described above or the flame retardant prepared by the preparation method described above in the preparation of epoxy resin.

[0022] Use of the flame retardant described above or the flame retardant prepared by the preparation method described above in the preparation of an adsorbent.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) The present invention improves the carbonization of phosphazene derivatives in polymer materials by reacting a substance containing a condensed aromatic hydrocarbon structure with cyclophosphazene to undergo a nucleophilic substitution reaction, thereby achieving the purpose of condensed phase flame retardancy. At the same time, the amino groups in the raw materials cause different spatial structures on two different benzene rings, thereby making the final flame retardant effect better.

[0025] (2) The product prepared by the present invention is used as a flame retardant additive for polymer materials, and has the properties of good heat resistance, good synergistic effect, rich content of flame retardant elements, and high flame retardant efficiency;

[0026] (3) The product of the present invention has good adsorption capacity and can be used in dye wastewater treatment;

[0027] (4) The preparation method and post-treatment method of the present invention are simple, the reagents used are non-toxic, and there is no hidden danger of environmental pollution. In addition, the yield is high, and the economic cost is greatly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0029] Figure 1 This is an infrared structural characterization diagram of the flame retardant of Example 1 of the present invention;

[0030] Figure 2 This is a curve diagram showing the effect of adsorption time on the adsorption of methyl orange by flame retardant in Application Example 2 of the present invention;

[0031] Figure 3 This is a curve diagram showing the effect of the initial concentration of methyl orange on the adsorption of methyl orange by the flame retardant in Application Example 2 of the present invention;

[0032] Figure 4 This is a process flow chart for preparing PZS-PEI microspheres in Comparative Example 2 of the present invention. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Example 1

[0035] A method for preparing a flame retardant having the function of absorbing methyl orange comprises the following specific steps:

[0036] (1) Dissolve 1.7383 g of hexachlorocyclotriphosphazene and 2.373 g of 1,5-naphthalenediamine (molar ratio 1:3) in 50 ml of toluene respectively, mix them evenly and transfer them to a three-necked flask equipped with a magnetic bar and a condensation reflux device; start stirring, add 3 ml of triethylamine, introduce nitrogen and heat to 110 °C for reflux reaction for 12 h, and a large amount of gray-black precipitate is generated at the bottom of the flask;

[0037] (2) After the reaction is completed, the mixture is cooled and allowed to stand, and filtered under reduced pressure. The solid matter is collected and washed with tetrahydrofuran three times and then with deionized water twice to obtain a gray-black solid. The solid is dried at 90°C in a vacuum to obtain a flame retardant with the function of adsorbing methyl orange. The yield is 34.9%.

[0038] Example 2

[0039] A method for preparing a flame retardant having the function of absorbing methyl orange comprises the following specific steps:

[0040] (1) Dissolve 1.7383 g of hexachlorocyclotriphosphazene and 2.373 g of 1,5-naphthalenediamine (molar ratio 1:3) in 50 ml of tetrahydrofuran, mix them evenly and transfer them to a three-necked flask equipped with a magnetic bar and a condensation reflux device; start stirring, add 3 ml of triethylamine, introduce nitrogen and heat to 68 °C for reflux reaction for 12 h, and a large amount of gray-black precipitate is generated at the bottom of the flask;

[0041] (2) After the reaction is completed, the mixture is cooled and allowed to stand, and filtered under reduced pressure. The solid matter is collected and washed with tetrahydrofuran three times and then with deionized water twice to obtain a gray-black solid. The solid is dried at 90°C in a vacuum to obtain a flame retardant with the function of adsorbing methyl orange. The yield is 11.8%.

[0042] Example 3

[0043] A method for preparing a flame retardant having the function of absorbing methyl orange comprises the following specific steps:

[0044] (1) Dissolve 1.7383 g of hexachlorocyclotriphosphazene and 1.582 g of 1,5-naphthalenediamine (molar ratio 1:2) in 50 ml of tetrahydrofuran, mix them evenly and transfer them to a three-necked flask equipped with a magnetic bar and a condensation reflux device; start stirring, add 3 ml of triethylamine, introduce nitrogen and heat to 68 °C for reflux reaction for 12 h, and a large amount of gray-black precipitate is generated at the bottom of the flask;

[0045] (2) After the reaction is completed, the mixture is cooled and allowed to stand, and filtered under reduced pressure. The solid matter is collected and washed with tetrahydrofuran three times and then with deionized water twice to obtain a gray-black solid. The solid is dried at 90°C in a vacuum to obtain a flame retardant with the function of adsorbing methyl orange, and the yield is 17%.

[0046] Example 4

[0047] A method for preparing a flame retardant having the function of absorbing methyl orange comprises the following specific steps:

[0048] (1) Dissolve 1.7383 g of hexachlorocyclotriphosphazene and 0.791 g of 1,5-naphthalenediamine (molar ratio 1:1) in 50 ml of tetrahydrofuran, mix them evenly and transfer them to a three-necked flask equipped with a magnetic bar and a condensation reflux device; start stirring, add 3 ml of triethylamine, introduce nitrogen and heat to 68 °C for reflux reaction for 12 h, and a large amount of gray-black precipitate is generated at the bottom of the flask;

[0049] (2) After the reaction is completed, the mixture is cooled and allowed to stand, and filtered under reduced pressure. The solid matter is collected and washed twice with tetrahydrofuran and then washed twice with deionized water to obtain a gray-black solid. The solid is dried at 90°C in a vacuum to obtain a flame retardant with the function of adsorbing methyl orange. The yield is 33.18%.

[0050] Example 5

[0051] A method for preparing a flame retardant having the function of absorbing methyl orange comprises the following specific steps:

[0052] (1) Dissolve 1.7383 g of hexachlorocyclotriphosphazene and 4.746 g of 1,5-naphthalenediamine (molar ratio 1:6) in 50 ml of tetrahydrofuran, mix them evenly and transfer them to a three-necked flask equipped with a magnetic bar and a condensation reflux device; start stirring, add 3 ml of triethylamine, introduce nitrogen and heat to 68 °C for reflux reaction for 48 h, and a large amount of gray-black precipitate is generated at the bottom of the flask;

[0053] (2) After the reaction is completed, the reaction is cooled and allowed to stand, and the solid matter is filtered under reduced pressure. The solid matter is collected and washed twice with tetrahydrofuran and then washed twice with deionized water to obtain a gray-black solid. The solid is dried at 90°C in a vacuum to obtain a flame retardant with the function of adsorbing methyl orange, and the yield is 16.5%;

[0054] like Figure 1 , which is the infrared structural characterization diagram of the flame retardants prepared in Examples 1 and 5. It can be seen from the figure that the relevant compounds were successfully prepared.

[0055] Application Example 1

[0056] Preparation of epoxy resin composites:

[0057] The flame retardants prepared in Examples 1 and 5 were added to the epoxy resin E-51 at a ratio of 5wt%, 7wt% and 9wt%, wherein the epoxy resin was 30g, the flame retardants were 1.5g, 2.1g and 2.7g respectively, and the curing agent DDM was 12g. After uniform mixing, the mixture was poured into a mold and placed in an oven. The mixture was cured at 100°C for 1h and at 150°C for 3h. After the curing was completed, all samples were cooled to room temperature and demolded to obtain epoxy composite materials, which were then subjected to a combustion test.

[0058] The results of the combustion test are shown in Table 1, where the test method is as follows: According to ASTM D3801-2006, a vertical combustion test is carried out on a vertical combustion tester to test the flammability of epoxy composite materials with a size of 100*150*3 mm; According to ASTM D2863, a limiting oxygen index (LOI) test of the epoxy composite material is carried out on an oxygen index analyzer, and the sample test size is 100*150*3 mm.

[0059] The UL-94 standard is a test method standard for material combustion performance developed by the American Underwriters Laboratories. It is used to evaluate the ability of materials to extinguish after being ignited. It stipulates that the flame retardant grade of plastics increases step by step from HB, V-2, V-1 to V-0, specifically:

[0060] HB: For samples with a thickness of 3-13mm, the burning speed is required to be less than 40mm / min; for samples with a thickness of less than 3mm, the burning speed is required to be less than 70mm / min, or the sample will be extinguished before the 100mm mark.

[0061] V-2: After two 10-second combustion tests on the sample, the flame goes out within 10-30 seconds, and the burning material may fall off;

[0062] V-1: After two 10-second combustion tests on the sample, the flame goes out within 10-30 seconds, and no burning material falls off;

[0063] V-0: After two 10-second combustion tests on the sample, the flame goes out within 10 seconds and no burning material falls off;

[0064] Table 1 Vertical combustion data results of epoxy composites

[0065]

[0066] It can be seen from the data in Table 1 that the flame retardant properties of the epoxy composite materials prepared by the flame retardants in Examples 1 and 5 have reached V-0 level, and the oxygen index of the epoxy composite materials can reach 29.9-31%.

[0067] Comparative Example 1

[0068] Materials selected from: Li Zhun. Study on the flame retardancy and mechanism of phosphorus-nitrogen heterocyclic compounds in epoxy resin [D]. University of Chinese Academy of Sciences (Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences), 2018.

[0069] The preparation method is:

[0070] (1) 1,8-diaminonaphthalene (21.36 g, 0.135 mol), hexachlorocyclotriphosphazene (10.43 g, 0.030 mol) and 200 mL of toluene were added to a round-bottom three-necked flask in sequence, and then triethylamine (19.70 g, 0.195 mol) was added to a constant pressure dropping funnel and connected to the round-bottom three-necked flask. The reaction flask was placed on a magnetic stirrer at room temperature for stirring to completely dissolve the solid; then triethylamine was slowly added dropwise, and a white precipitate was observed to form rapidly during the addition process. In order to prevent the precipitate from sticking together, a high rotation speed was required; after the addition was completed, the flask was placed in an oil bath and heated to 110°C, and the reaction was continued for 6 hours; during the reaction, nitrogen gas needed to be continuously introduced for protection;

[0071] (2) After the reaction, the reaction system was cooled to room temperature naturally, filtered with a Buchner funnel, and the residue was washed twice with 150 mL of tetrahydrofuran, and then repeatedly washed with water for five to eight times. After that, it was placed in a vacuum oven and heated at 80 ° C for 4 h. After drying, an off-white solid was obtained, which was the target product TNACP (15.95 g, yield 88.1%).

[0072] The specific process route is as follows:

[0073] .

[0074] The flame retardant obtained in Comparative Example 1 was used to prepare a composite material of epoxy resin:

[0075] The flame retardant TNACP and the bisphenol A epoxy resin DGEBA were mixed at 80°C in a certain proportion and stirred evenly. Then, DDM was added to the mixed system (the mass ratio of DDM to epoxy groups in the epoxy resin was 40%), and the mixture was heated and stirred until the DDM was completely dissolved. Then, the mixture was quickly transferred to a vacuum oven preheated to 80°C, degassed for 5 minutes, poured into a mold, and heated at 120°C for 2 hours and 170°C for 4 hours in a vacuum oven. After it was slowly cooled, the sample was taken out of the mold to obtain a flame retardant epoxy resin, and then the same combustion test was carried out. The results are shown in Table 2.

[0076] Table 2 Vertical combustion data results of epoxy composites

[0077]

[0078] It can be seen from the above table that when the mass fraction of the flame retardant in Examples 1 and 5 is greater than 5wt% compared with Comparative Example 1, the oxygen index of Comparative Example 1 does not exceed the relevant indicators of Examples 1 and 5. It can be seen that the product obtained by the technical solution of the present invention has better combustion index performance in epoxy resin.

[0079] Application Example 2

[0080] Adsorption test:

[0081] The experimental steps are as follows: prepare 1L of 500mg / L methyl orange original solution, take 0.1mL, 0.2mL, 0.3mL, 0.4mL, 0.5mL of 500mg / L methyl orange original solution and dilute to 25mL to obtain 2mg / L, 4mg / L, 6mg / L, 8mg / L, 10mg / L gradient solutions, perform ultraviolet absorption spectrum test at 464nm, and thus obtain a standard curve of 2-10mg / L methyl orange concentration for subsequent concentration calculation;

[0082] Effect of adsorption time on the adsorption of methyl orange by this flame retardant

[0083] At 25°C, 10 mg of the flame retardant prepared in Example 1 and 25 mL of methyl orange wastewater were mixed and shaken for reaction at a shaking rate of 150 r / min and an initial methyl orange concentration of 150 mg / L. The test was performed at 15 min, 60 min, 240 min, 300 min, and 360 min. The results are as follows: Figure 2 As shown, it can be seen that the longer the adsorption time, the more obvious the adsorption effect. The longest adsorption time can reach adsorption equilibrium after 6 hours. The adsorption time is faster than that of many traditional adsorbents.

[0084] Effect of initial concentration of methyl orange on the adsorption of methyl orange by the flame retardant

[0085] At 25°C, 10 mg of the flame retardant prepared in Example 1 and 25 mL of methyl orange wastewater of different concentrations were respectively taken for oscillation mixing reaction at an oscillation rate of 150 r / min. After adsorption for 6 hours, the results were as follows: Figure 3 As shown, it can be seen that the adsorption of methyl orange by the flame retardant increases with the increase of its initial concentration. When the initial concentration of methyl orange reaches 300 mg / L, the product reaches the maximum adsorption limit, the equilibrium adsorption amount is about 411 mg / g, and the removal rate can reach 60%;

[0086] Comparative Example 2

[0087] Materials selected from: Yu S, Feng M, Wu P, et al. Polyethyleneimine-graftedpolyphosphazene microspheres for rapid and efficient capture of anionic dyes from wastewater[J]. Materials Today Chemistry, 21 (2021) 100525.

[0088] like Figure 4 , the preparation method is as follows:

[0089] (1) 0.4 g HCCP, 0.58 g BPS (the molar ratio of HCCP:BPS is 1.5:3), 100 mL acetonitrile and 3 mL TEA were added to a 250 mL three-necked flask and reacted at room temperature for 2 h in an ultrasonic wave (40 kHz, 100 W) to obtain white powder PZS-Cl microspheres, which were then centrifuged at 4000 rpm for 10 min and rinsed twice with deionized water and anhydrous ethanol respectively; finally, the obtained PZS-Cl microspheres were dried at 65 °C overnight, and the yield of PZS-Cl microspheres was about 71.6%;

[0090] (2) Add 54 mg of PZS-Cl microspheres and 40 mg of PEI into a 250 ml three-necked flask, mix them evenly in 40 ml of acetonitrile, and add 2 ml of TEA. Ultrasonic reaction is carried out at room temperature for 3 h to allow the grafting reaction of PZSCl and PEI. The reaction product PZS-PEI microspheres are separated by centrifugation, and then rinsed with deionized water and anhydrous ethanol several times to remove impurities. Finally, the obtained solid sample is dried at 65 °C overnight to obtain PZS-PEI microspheres.

[0091] The effect of the initial concentration of methyl orange on the adsorption of methyl orange by PZS-PEI microspheres was tested. The results are shown in the curve of the effect of the initial concentration of methyl orange on PZS-PEI microspheres in the above article. When the initial concentration of methyl orange increases, the adsorption amount of PZS-PEI will gradually increase, and the equilibrium is reached when the maximum adsorption amount is about 260 mg / g; therefore, in comparison, the maximum adsorption amount of this product is higher than that of PZS-PEI.

[0092] The various embodiments are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to in detail.

[0093] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A flame retardant having the function of absorbing methyl orange, characterized in that: The structural formula of the flame retardant is as follows: .

2. The method for preparing a flame retardant having the function of adsorbing methyl orange as claimed in claim 1, characterized in that: The specific steps include: After adding hexachlorocyclotriphosphazene and 1,5-naphthalenediamine into a solvent and dissolving them, triethylamine is added and refluxed to react, and after the reaction is completed, a precipitate is filtered, washed and dried to obtain a flame retardant having the function of absorbing methyl orange. The molar ratio of the hexachlorocyclotriphosphazene to the 1,5-naphthalenediamine is 1:3-10; the reflux temperature is 110°C or 68°C; the washing is 2-3 times of tetrahydrofuran washing and then 2 times of deionized water washing; the drying is vacuum drying at 90°C; and the reflux reaction is carried out under a nitrogen atmosphere.

3. The method for preparing a flame retardant having the function of adsorbing methyl orange according to claim 2, characterized in that: The molar ratio of the hexachlorocyclotriphosphazene to the triethylamine is 1-5:1-30.

4. The method for preparing a flame retardant having the function of adsorbing methyl orange according to claim 2, characterized in that: The solvent is tetrahydrofuran or toluene.

5. The method for preparing a flame retardant having the function of adsorbing methyl orange according to claim 2, characterized in that: The reaction time is 12-48h.

6. The method for preparing a flame retardant having the function of adsorbing methyl orange according to claim 2, characterized in that: The reaction was carried out under nitrogen atmosphere.

7. Use of the flame retardant according to claim 1 or the flame retardant prepared by the preparation method according to any one of claims 2 to 6 in the preparation of epoxy resin.

8. Use of the flame retardant according to claim 1 or the flame retardant prepared by the preparation method according to any one of claims 2 to 6 in preparing an adsorbent, characterized in that: The adsorbent adsorbs methyl orange.

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