An environmentally friendly water-based composite flame retardant and its preparation method

Abstract

This invention relates to an environmentally friendly water-based composite flame retardant and its preparation method, belonging to the field of flame retardant preparation technology. The environmentally friendly water-based composite flame retardant formulation is as follows: by weight percentage, modified graphene 1.5-3.0%, nano-magnesium hydroxide 8-12%, nano-sodium silicate 5-8%, surfactant 0.5-1.0%, and the balance being deionized water. Modified graphene, nano-magnesium hydroxide, and sodium silicate produce a synergistic flame-retardant effect. Modified graphene builds a dense carbon layer framework, magnesium hydroxide decomposes endothermally, and magnesium oxide acts as a barrier to reflect heat radiation, while sodium silicate promotes the formation of a silicate glassy carbon layer. The combination of these three components significantly improves the oxygen index of the material. The flame retardant prepared by this invention possesses both excellent thermal conductivity and environmentally friendly properties, and can be widely used in fire fighting and flame retardant applications.

Description

Technical Field

[0001] This invention belongs to the field of flame retardant preparation technology, and relates to an environmentally friendly water-based composite flame retardant and its preparation method. Background Technology

[0002] Traditional fire extinguishing agents have many limitations. Dry powder fire extinguishing agents leave environmentally polluting residues and are prone to reignition; gaseous fire extinguishing agents (such as heptafluoropropane) are facing elimination due to their high global warming potential; and ordinary water-based fire extinguishing agents are ineffective against oil fires and are easily conductive. Graphene, as a two-dimensional nanomaterial, possesses superhydrophobicity, high specific surface area, and chemical stability, and can rapidly conduct heat and isolate oxygen. Existing technologies have attempted to incorporate graphene into the preparation process of fire extinguishing agents, but problems such as poor dispersibility, complex preparation, or limited functionality remain. Therefore, there is an urgent need to develop composite flame retardants that are both highly effective at extinguishing fires and environmentally friendly and non-toxic. Summary of the Invention

[0003] The purpose of this invention is to provide an environmentally friendly water-based composite flame retardant and its preparation method, which has good flame retardant properties.

[0004] The objective of this invention can be achieved through the following technical solutions:

[0005] An environmentally friendly water-based composite flame retardant, wherein the formulation of the environmentally friendly water-based composite flame retardant is as follows, by weight percentage: 1.5-3.0% modified graphene, 8-12% nano magnesium hydroxide, 5-8% nano sodium silicate, 0.5-1.0% surfactant, and the balance being deionized water;

[0006] The preparation method of modified graphene is as follows:

[0007] S1-1: Take 100 parts by weight of graphene oxide dispersion, ultrasonically disperse for 30-60 min, add 5-10 parts by weight of ammonium dihydrogen phosphate, adjust the pH to 9.0-9.5 with 1 M ammonia water, stir at 500-600 r / min at 70-80 ℃ for 4-8 h, wash with deionized water until the pH of the solution is 7.0, and then redisperse in deionized water to obtain dispersion A with a solid-liquid mass ratio of 1:100;

[0008] S1-2: Add γ-aminopropyltriethoxysilane to dispersion A, adjust the pH to 5.0-6.0 with 0.5 M acetic acid, stir at 300-400 r / min for 2-3 h at 50-60℃, wash with anhydrous ethanol, freeze dry at -40℃ for 12 h to obtain powder B;

[0009] S1-3: Mix powder B with starch phosphate and ball mill in a ball mill for 1-2 h to obtain the modified graphene.

[0010] As a preferred embodiment of the present invention, the surfactant is one or both of sodium dodecylbenzenesulfonate and sodium fatty alcohol polyoxyethylene ether sulfate.

[0011] As a preferred embodiment of the present invention, the mass fraction of graphene oxide in the graphene oxide dispersion in S1-1 is 3-5%.

[0012] As a preferred embodiment of the present invention, the amount of γ-aminopropyltriethoxysilane added in S1-2 is 5-10% of the mass of dispersion A.

[0013] As a preferred technical solution of the present invention, in S1-3, powder B and starch-based phosphate are mixed at a mass ratio of (4~6):1.

[0014] As a preferred technical solution of the present invention, the ball milling speed in S1-3 is 100~150 r / min.

[0015] A method for preparing an environmentally friendly water-based composite flame retardant, the specific steps of which are as follows:

[0016] S7-1: Mix nano magnesium hydroxide, nano sodium silicate and deionized water according to the formula and add them to a high-shear emulsification pump for high-speed shearing for 30~50 min at a temperature of 30~40℃ to obtain mixture C;

[0017] S7-2: Treat mixture C with an electric field at 2000V for 10~15 min, then let it stand for 24 h to obtain mixture D;

[0018] S7-3: Modified graphene and surfactant are added to mixture D in sequence and stirred at 80°C for 1-2 h to obtain the composite flame retardant.

[0019] As a preferred embodiment of the present invention, the rotational speed in S7-1 is 15000~17000 rpm.

[0020] As a preferred embodiment of the present invention, the stirring speed in step S7-3 is 800~1000 rpm.

[0021] An application of an environmentally friendly water-based composite flame retardant, wherein the composite flame retardant is used in the field of fire extinguishing, the composite flame retardant is mixed with deionized water at a volume ratio of 1:(5~10) to obtain a composite flame retardant dilution, which is then filled into fire-fighting equipment or used directly for spray extinguishing.

[0022] The introduction of ammonium dihydrogen phosphate provides phosphate ions, which react with the hydroxyl and epoxy groups on the surface of graphene oxide to form esterification groups, promoting char formation during combustion and thus improving the flame retardant properties of graphene. It also enhances the interfacial interaction between graphene and inorganic flame retardants such as magnesium hydroxide, and further improves its dispersion stability. The introduction of ammonia creates an alkaline environment, accelerating the phosphorylation reaction process; simultaneously, it removes acidic impurities from the surface of graphene oxide, improving its purity.

[0023] γ-aminopropyltriethoxysilane hydrolyzes to generate silanol groups, which undergo condensation reactions with hydroxyl groups on the graphene surface to form covalent bonds. This can introduce amino functional groups on the graphene surface, enhancing the interfacial bonding force between graphene and polymers. At the same time, the silane segments form a hydrophobic layer on the graphene surface, reducing agglomeration and resulting in a more uniform particle size distribution after freeze-drying.

[0024] Starch phosphate esters provide additional phosphate groups, forming a synergistic flame-retardant network with the phosphorylated structure on the graphene surface; the starch backbone significantly enhances the thermal stability of the char layer and reduces combustion dripping; it also improves the dispersibility of graphene in the substrate, reducing the tendency to agglomerate; and it can reduce the amount of graphene used in flame retardants. Ball milling promotes the uniform compounding of graphene and starch phosphate esters through mechanical force; simultaneously reducing the thickness of graphene sheets and increasing the specific surface area.

[0025] In this invention, modified graphene has a synergistic effect with nano-magnesium hydroxide and nano-sodium silicate.

[0026] The two-dimensional sheet structure of graphene can build a carbon layer framework, reduce carbon layer porosity, and block oxygen permeation. The introduced phosphate groups catalyze the dehydration of polymers to form carbon during combustion, creating a continuous graphitized carbon layer. Nano-sized magnesium hydroxide has an endothermic effect, absorbing a large amount of heat and lowering the material's surface temperature. The magnesium oxide nanoparticles generated by endothermic decomposition deposit on the carbon layer surface, forming a dense inorganic barrier that reflects heat radiation. Nano-sized sodium silicate generates silicic acid during combustion, which further dehydrates to form a silicate glassy substance, promoting silanization of the carbon layer. The silicate and graphene carbon layer form a brick-and-mortar structure, significantly improving the carbon layer's strength.

[0027] Graphene possesses excellent thermal conductivity, enabling rapid heat transfer from localized hotspots to the entire material surface. It forms a three-dimensional thermally conductive network within the polymer matrix, thereby enhancing the material's thermal diffusivity. Nano-sized magnesium hydroxide absorbs heat and generates water vapor during decomposition, forming a temporary thermal buffer layer that slows down the thermal degradation rate. The combination of nano-sized magnesium hydroxide and the graphene thermal pathway reduces the peak heat release rate of the material. Nano-sized sodium silicate forms a silicate glassy substance at high temperatures, covering the material surface and preventing further thermal decomposition; it also synergistically interacts with the magnesium oxide barrier, increasing the char content and improving thermal stability.

[0028] The beneficial effects of this invention are:

[0029] This invention introduces phosphate groups into graphene oxide to construct a highly efficient char layer, improving flame retardancy. Simultaneously, it forms chemical bonds with magnesium hydroxide, effectively enhancing interfacial bonding strength. Silanization treatment forms a covalent anchoring layer, endowing the graphene surface with amino functional groups and improving compatibility with the polymer matrix. Starch phosphate composites generate a dual flame-retardant network, improving the thermal stability of the char layer and preventing collapse, reducing combustion dripping rate, and effectively reducing the amount of graphene required. Furthermore, the modified graphene exhibits a synergistic effect with nano-magnesium hydroxide and nano-sodium silicate, constructing a three-dimensional char layer-inorganic barrier composite system, further enhancing the flame-retardant effect. Detailed Implementation

[0030] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following detailed description of the specific implementation methods, structures, features and effects of the present invention, in conjunction with embodiments, is provided below.

[0031] In the embodiments and comparative examples of this invention:

[0032] Graphene oxide: purchased from Anhui Kerun Nanotechnology Co., Ltd.

[0033] Ammonium dihydrogen phosphate: purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0034] Ammonia solution: purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0035] γ-aminopropyltriethoxysilane: purchased from Danyang Organosilicon Materials Industry Co., Ltd.

[0036] Starch phosphate: purchased from Nanjing Songguan Biotechnology Co., Ltd.;

[0037] Sodium dodecylbenzenesulfonate: purchased from Shandong Hengli Additives Co., Ltd.;

[0038] Sodium fatty alcohol polyoxyethylene ether sulfate: purchased from Hubei Maikesi Fine Chemical Technology Co., Ltd.;

[0039] Nano magnesium hydroxide: purchased from Wuhan Lvjing Fenghua Biotechnology Co., Ltd.;

[0040] Nano sodium silicate: purchased from Chengdu Xindu Wuyi Sodium Silicate Factory.

[0041] Example 1

[0042] An environmentally friendly water-based composite flame retardant, the formulation of which is as follows (by weight percentage): 2% modified graphene, 10% nano magnesium hydroxide, 6% nano sodium silicate, 0.8% sodium dodecylbenzenesulfonate, and the balance being deionized water.

[0043] The preparation method of modified graphene is as follows:

[0044] S1-1: Take 100 parts by weight of a 4% graphene oxide dispersion, ultrasonically disperse for 45 min, add 7 parts by weight of ammonium dihydrogen phosphate, adjust the pH to 9.2 with 1 M ammonia water, stir at 75 ℃ and 550 r / min for 6 h, wash with deionized water until the solution pH is 7.0, and then redisperse in deionized water to obtain dispersion A with a solid-liquid mass ratio of 1:100.

[0045] S1-2: 7% of γ-aminopropyltriethoxysilane by mass of dispersion A was added to dispersion A. The pH was adjusted to 5.5 using 0.5 M acetic acid. The mixture was stirred at 350 r / min for 2.5 h at 55 °C. After washing with anhydrous ethanol, the mixture was freeze-dried at -40 °C for 12 h to obtain powder B.

[0046] S1-3: Mix powder B with starch phosphate at a mass ratio of 5:1, place in a ball mill and ball mill for 1.5 h at a ball milling speed of 120 r / min to obtain the modified graphene.

[0047] A method for preparing an environmentally friendly water-based composite flame retardant, the specific steps of which are as follows:

[0048] S7-1: According to the formula, nano magnesium hydroxide, nano sodium silicate and deionized water are mixed and added to a high-shear emulsification pump for high-speed shearing for 40 min at a speed of 16000 rpm and a temperature of 35℃ to obtain mixture C;

[0049] S7-2: Mixture C was subjected to electric field treatment at 2000V for 12 min, and then allowed to stand for 24 h to obtain mixture D;

[0050] S7-3: Modified graphene and sodium dodecylbenzenesulfonate were added to the mixture D in sequence, and stirred at 80°C for 1.5 h at a stirring speed of 900 rpm to obtain the composite flame retardant.

[0051] An application of an environmentally friendly water-based composite flame retardant, wherein the composite flame retardant is used in the field of fire extinguishing, and the composite flame retardant is mixed with deionized water at a volume ratio of 1:10 to obtain a composite flame retardant dilution, which is directly used for spray fire extinguishing.

[0052] Example 2

[0053] An environmentally friendly water-based composite flame retardant, the formulation of which is as follows (by weight percentage): 1.5% modified graphene, 8% nano magnesium hydroxide, 5% nano sodium silicate, 0.5% sodium fatty alcohol polyoxyethylene ether sulfate, and the balance being deionized water.

[0054] The preparation method of modified graphene is as follows:

[0055] S1-1: Take 100 parts by weight of a 3% graphene oxide dispersion, ultrasonically disperse for 30 min, add 5 parts by weight of ammonium dihydrogen phosphate, adjust the pH to 9.0 with 1 M ammonia water, stir at 70 ℃ and 500 r / min for 4 h, wash with deionized water until the solution pH is 7.0, and then redisperse in deionized water to obtain dispersion A with a solid-liquid mass ratio of 1:100.

[0056] S1-2: Add 5% by mass of γ-aminopropyltriethoxysilane to dispersion A, adjust the pH to 5.0 with 0.5 M acetic acid, stir at 300 r / min for 2 h at 50 °C, wash with anhydrous ethanol, freeze dry at -40 °C for 12 h to obtain powder B;

[0057] S1-3: Mix powder B with starch phosphate at a mass ratio of 4:1, place in a ball mill and ball mill for 1 hour at a speed of 100 r / min to obtain the modified graphene.

[0058] A method for preparing an environmentally friendly water-based composite flame retardant, the specific steps of which are as follows:

[0059] S7-1: According to the formula, nano magnesium hydroxide, nano sodium silicate and deionized water are mixed and added to a high-shear emulsification pump for high-speed shearing for 30 min at a speed of 15000 rpm and a temperature of 30℃ to obtain mixture C;

[0060] S7-2: Mixture C was subjected to electric field treatment at 2000V for 10 min, and then allowed to stand for 24 h to obtain mixture D;

[0061] S7-3: Modified graphene and sodium fatty alcohol polyoxyethylene ether sulfate were added to the mixture D in sequence, and stirred at 80°C for 1 h at a stirring speed of 800 rpm to obtain the composite flame retardant.

[0062] An application of an environmentally friendly water-based composite flame retardant, wherein the composite flame retardant is used in the field of fire extinguishing, and the composite flame retardant is mixed with deionized water at a volume ratio of 1:10 to obtain a composite flame retardant dilution, which is directly used for spray fire extinguishing.

[0063] Example 3

[0064] An environmentally friendly water-based composite flame retardant, the formulation of which is as follows (by weight percentage): 3.0% modified graphene, 12% nano magnesium hydroxide, 8% nano sodium silicate, 1.0% sodium dodecylbenzenesulfonate, and the balance being deionized water.

[0065] The preparation method of modified graphene is as follows:

[0066] S1-1: Take 100 parts by weight of a 5% graphene oxide dispersion, ultrasonically disperse for 60 min, add 10 parts by weight of ammonium dihydrogen phosphate, adjust the pH to 9.5 with 1 M ammonia water, stir at 80 ℃ and 600 r / min for 8 h, wash with deionized water until the solution pH is 7.0, and then redisperse in deionized water to obtain dispersion A with a solid-liquid mass ratio of 1:100.

[0067] S1-2: Add 5-10% by mass of γ-aminopropyltriethoxysilane to dispersion A, adjust the pH to 6.0 with 0.5 M acetic acid, stir at 400 r / min for 3 h at 60 °C, wash with anhydrous ethanol, freeze dry at -40 °C for 12 h to obtain powder B.

[0068] S1-3: Mix powder B with starch phosphate at a mass ratio of 6:1, place in a ball mill and ball mill for 2 h at a ball mill speed of 150 r / min to obtain the modified graphene.

[0069] A method for preparing an environmentally friendly water-based composite flame retardant, the specific steps of which are as follows:

[0070] S7-1: According to the formula, nano magnesium hydroxide, nano sodium silicate and deionized water are mixed and added to a high-shear emulsification pump for high-speed shearing for 50 min at a speed of 17000 rpm and a temperature of 40℃ to obtain mixture C;

[0071] S7-2: Mixture C was subjected to electric field treatment at 2000V for 15 min, and then allowed to stand for 24 h to obtain mixture D;

[0072] S7-3: Modified graphene and surfactant are added to mixture D in sequence, and stirred at 80°C for 2 h at a stirring speed of 1000 rpm to obtain the composite flame retardant.

[0073] An application of an environmentally friendly water-based composite flame retardant, wherein the composite flame retardant is used in the field of fire extinguishing, and the composite flame retardant is mixed with deionized water at a volume ratio of 1:10 to obtain a composite flame retardant dilution, which is directly used for spray fire extinguishing.

[0074] Comparative Example 1

[0075] Ammonium dihydrogen phosphate was not added during the preparation of the modified graphene, and the remaining steps were the same as in Example 1.

[0076] Comparative Example 2

[0077] In the preparation of modified graphene, starch phosphate was not added, and the remaining steps were the same as in Example 1.

[0078] Comparative Example 3

[0079] No modification was made to the graphene oxide; the remaining steps were the same as in Example 1.

[0080] Comparative Example 4

[0081] Without adding modified graphene oxide, the remaining steps are the same as in Example 1.

[0082] Comparative Example 5

[0083] γ-aminopropyltriethoxysilane was not added during the preparation of the modified graphene, and the remaining steps were the same as in Example 1.

[0084] Comparative Example 6

[0085] Without adding nano-magnesium hydroxide, the remaining steps are the same as in Example 1.

[0086] Comparative Example 7

[0087] Without adding nano-sodium silicate, the remaining steps are the same as in Example 1.

[0088] Flame retardant performance test

[0089] The limiting oxygen index of the flame retardants prepared in the examples and comparative examples was tested according to GB / T 2406.2-2009 standard, and the experimental results are recorded in the table below.

[0090]

[0091] As can be seen from the examples and comparative data, the flame retardant prepared by the present invention has a good flame retardant effect.

[0092] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention are still within the scope of the present invention.

Claims

1. An environmentally friendly water-based composite flame retardant, characterized in that, The formulation of the environmentally friendly water-based composite flame retardant is as follows: by weight percentage, modified graphene 1.5~3.0%, nano magnesium hydroxide 8~12%, nano sodium silicate 5~8%, surfactant 0.5~1.0%, and the balance is deionized water; The preparation method of modified graphene is as follows: S1-1: Take 100 parts by weight of graphene oxide dispersion, ultrasonically disperse for 30-60 min, add 5-10 parts by weight of ammonium dihydrogen phosphate, adjust the pH to 9.0-9.5 with 1 M ammonia water, stir at 500-600 r / min at 70-80 ℃ for 4-8 h, wash with deionized water until the pH of the solution is 7.0, and then redisperse in deionized water to obtain dispersion A with a solid-liquid mass ratio of 1:100; S1-2: Add γ-aminopropyltriethoxysilane to dispersion A, adjust the pH to 5.0-6.0 with 0.5 M acetic acid, stir at 300-400 r / min for 2-3 h at 50-60℃, wash with anhydrous ethanol, freeze dry at -40℃ for 12 h to obtain powder B; S1-3: Mix powder B with starch phosphate and ball mill in a ball mill for 1-2 h to obtain the modified graphene.

2. The environmentally friendly water-based composite flame retardant according to claim 1, characterized in that, The surfactant is one or both of sodium dodecylbenzenesulfonate and sodium fatty alcohol polyoxyethylene ether sulfate.

3. The environmentally friendly water-based composite flame retardant according to claim 1, characterized in that, The mass fraction of graphene oxide in the graphene oxide dispersion in S1-1 is 3-5%.

4. The environmentally friendly water-based composite flame retardant according to claim 1, characterized in that, The amount of γ-aminopropyltriethoxysilane added in S1-2 is 5-10% of the mass of dispersion A.

5. The environmentally friendly water-based composite flame retardant according to claim 1, characterized in that, In S1-3, powder B and starch-based phosphate are mixed at a mass ratio of (4~6):

1.

6. The environmentally friendly water-based composite flame retardant according to claim 1, characterized in that, The ball milling speed in S1-3 is 100~150 r / min.

7. A method for preparing an environmentally friendly water-based composite flame retardant as described in any one of claims 1 to 6, characterized in that, The specific steps of the preparation method are as follows: S7-1: Mix nano magnesium hydroxide, nano sodium silicate and deionized water according to the formula and add them to a high-shear emulsification pump for high-speed shearing for 30~50 min at a temperature of 30~40℃ to obtain mixture C; S7-2: Treat mixture C with an electric field at 2000V for 10~15 min, then let it stand for 24 h to obtain mixture D; S7-3: Modified graphene and surfactant are added to mixture D in sequence and stirred at 80°C for 1-2 h to obtain the composite flame retardant.

8. The preparation method of an environmentally friendly water-based composite flame retardant according to claim 7, characterized in that, The rotational speed in S7-1 is 15000~17000 rpm.

9. The preparation method of an environmentally friendly water-based composite flame retardant according to claim 7, characterized in that, The stirring speed in S7-3 is 800~1000 rpm.

10. The application of the environmentally friendly water-based composite flame retardant as described in claim 1, characterized in that, The composite flame retardant is used in the field of fire fighting. The composite flame retardant is mixed with deionized water at a volume ratio of 1: (5~10) to obtain a composite flame retardant dilution, which is then filled into fire fighting equipment or used directly for spray fire extinguishing.

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