Environment-friendly water-based composite flame retardant and preparation method thereof

Abstract

The invention relates to an environment-friendly water-based composite flame retardant and a preparation method thereof, and belongs to the technical field of flame retardant preparation. A formula of the environment-friendly water-based composite flame retardant comprises the following components in percentage by weight: 1.5-3.0% of modified graphene, 8-12% of nano magnesium hydroxide, 5-8% of nano sodium silicate, 0.5-1.0% of a surfactant and the balance of deionized water. Modified graphene, nano magnesium hydroxide and sodium silicate generate a synergistic flame-retardant effect, the modified graphene builds a compact carbon layer framework, magnesium hydroxide reflects heat radiation through endothermic decomposition and magnesium oxide barrier, sodium silicate promotes formation of a silicate glassy carbon layer, and the oxygen index of the material is remarkably increased through compounding of the three. The flame retardant prepared by the invention has excellent thermal conductivity and environment-friendly characteristic, and can be widely applied to the fields of fire extinguishing and flame retardance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of flame retardant preparation, and relates to an environmentally-friendly water-based composite flame retardant and a preparation method thereof. BACKGROUND

[0002] Traditional fire extinguishing agents have many limitations, dry powder fire extinguishing agent residues pollute the environment and are prone to reignition, gaseous fire extinguishing agents (such as heptafluoropropane) face elimination due to high global warming potential, and ordinary water-based fire extinguishing agents have poor effect on oil fires and are prone to conduct electricity. Graphene, as a two-dimensional nanomaterial, has superhydrophobicity, high specific surface area and chemical stability, can quickly conduct heat and isolate oxygen. Existing technologies have attempted to introduce graphene into the preparation process of fire extinguishing agents, but there are still problems such as poor dispersibility, complex preparation or single function. Therefore, it is urgent to develop a composite flame retardant with high efficient fire extinguishing and environmental protection and non-toxicity. SUMMARY

[0003] The application aims to provide an environmentally-friendly water-based composite flame retardant and a preparation method thereof, which have the characteristics of good flame retardancy.

[0004] The application can be achieved by the following technical solutions. An environmentally-friendly water-based composite flame retardant, the formula of the environmentally-friendly water-based composite flame retardant is as follows, in terms of 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 the modified graphene is as follows, S1-1: 100 parts by weight of graphene oxide dispersion liquid is ultrasonically dispersed for 30-60 min, 5-10 parts by weight of ammonium dihydrogen phosphate is added, the pH is adjusted to 9.0-9.5 by using ammonia water with a concentration of 1 M, stirring is carried out at a speed of 500-600 r / min and a temperature of 70-80 ℃ for 4-8 h, washing is carried out by using deionized water until the pH of the solution is 7.0, and the dispersion liquid A with a solid-liquid mass ratio of 1:100 is obtained by re-dispersing in deionized water; S1-2: gamma-aminopropyltriethoxysilane is added to the dispersion liquid A, the pH is adjusted to 5.0-6.0 by using acetic acid with a concentration of 0.5 M, stirring is carried out at a speed of 300-400 r / min and a temperature of 50-60 ℃ for 2-3 h, washing is carried out by using anhydrous ethanol, and powder B is obtained by freeze-drying at-40 ℃ for 12 h; S1-3: powder B is mixed with starch phosphate, and ball milling is carried out in a ball mill for 1-2 h to obtain the modified graphene.

[0005] As a preferred technical solution of the application, the surfactant is one or both of sodium dodecyl benzene sulfonate and sodium fatty alcohol polyoxyethylene ether sulfate.

[0006] As a preferred technical solution of the present application, the mass fraction of graphene oxide in the graphene oxide dispersion solution in S1-1 is 3-5%.

[0007] As a preferred technical solution of the present application, the addition amount of gamma-aminopropyl triethoxysilane in S1-2 is 5-10% of the mass of dispersion solution A.

[0008] As a preferred technical solution of the present application, the powder B and the starch-based phosphate in S1-3 are mixed in a mass ratio of (4-6):1.

[0009] As a preferred technical solution of the present application, the ball milling speed in S1-3 is 100-150 r / min.

[0010] A preparation method of an environmentally friendly water-based composite flame retardant, the specific steps of the preparation method are as follows, S7-1: According to the formula, mix nano-magnesium hydroxide, nano-sodium silicate and deionized water and add to a high shear emulsification pump for high speed shearing for 30-50 min, the temperature is 30-40℃, to obtain mixed liquid C; S7-2: The mixed liquid C is treated by electric field under 2000V voltage for 10-15 min, and then it is placed for 24h to obtain mixed liquid D; S7-3: The modified graphene and the surfactant are added to the mixed liquid D in sequence, and stirred at 80℃ for 1-2h to obtain the composite flame retardant.

[0011] As a preferred technical solution of the present application, the speed in S7-1 is 15000-17000 rpm.

[0012] As a preferred technical solution of the present application, the stirring speed in S7-3 is 800-1000 rpm.

[0013] The application of an environmentally friendly water-based composite flame retardant, the composite flame retardant is applied to the field of fire extinguishing, the composite flame retardant is mixed with deionized water in a volume ratio of 1:(5-10) to obtain a composite flame retardant diluent, which is filled into fire fighting equipment or directly used for jet fire extinguishing.

[0014] The introduction of ammonium dihydrogen phosphate can provide phosphate ions, which can react with the hydroxyl and epoxy groups on the surface of graphene oxide to introduce phosphate groups, which can promote the formation of carbon layer during combustion, thereby improving the flame retardant performance of graphene; enhance the interfacial interaction of graphene and inorganic flame retardants such as magnesium hydroxide, and further improve its dispersion stability. Among them, the introduction of ammonia water creates an alkaline environment, accelerates the progress of phosphatization reaction; at the same time, the acidic impurities on the surface of graphene oxide are removed, and the purity is improved.

[0015] The gamma-aminopropyl triethoxysilane is hydrolyzed to generate silanol groups, which are condensed with the hydroxyl groups on the surface of the graphene to form covalent bond; the amino functional groups can be introduced on the surface of the graphene to improve the interfacial bonding force between the graphene and the polymer; meanwhile, the silane segments form a hydrophobic layer on the surface of the graphene, reduce agglomeration, and make the particle size distribution after freeze-drying more uniform.

[0016] The starch phosphate can provide additional phosphate groups to form a synergistic flame-retardant network with the phosphorylated structure on the surface of the graphene; the starch skeleton can significantly enhance the thermal stability of the carbon layer and reduce burning dripping; meanwhile, the starch skeleton can also improve the dispersibility of the graphene in the base material and reduce the agglomeration tendency; and the amount of graphene in the flame retardant can also be reduced.

[0017] The modified graphene in the application has a synergistic effect with the nano-magnesium hydroxide and the nano-sodium silicate.

[0018] The two-dimensional sheet structure of the graphene can build a carbon layer skeleton, reduce the porosity of the carbon layer, block the penetration of oxygen, and the introduced phosphate groups can catalyze the dehydration of the polymer into carbon during combustion to form a continuous graphitized carbon layer. The nano-magnesium hydroxide has an endothermic effect and can absorb a large amount of heat to reduce the surface temperature of the material; the magnesium oxide nanoparticles generated by the endothermic decomposition are deposited on the surface of the carbon layer to form a dense inorganic barrier to reflect heat radiation. The nano-sodium silicate generates silicic acid during combustion, which further dehydrates to form silicate glassy substances, promotes the siliconization of the carbon layer, and forms a brick-mud structure with the graphene carbon layer, significantly improving the strength of the carbon layer.

[0019] The graphene has excellent thermal conductivity, which can quickly conduct the heat of local hot spots to the entire material surface to form a three-dimensional heat conduction network in the polymer matrix, thereby improving the thermal diffusion coefficient of the material. The nano-magnesium hydroxide absorbs heat and generates water vapor when it decomposes, forming a temporary heat buffer layer to slow down the rate of thermal degradation. The combination of nano-magnesium hydroxide and graphene heat conduction path reduces the peak value of the material heat release rate. The nano-sodium silicate generates silicate glassy substances at high temperatures, which cover the surface of the material to prevent further thermal decomposition; and has a synergistic effect with the magnesium oxide barrier to increase the residual carbon content of the material and improve the thermal stability.

[0020] The beneficial effects of the application are as follows: The application introduces a phosphate group into graphene oxide, constructs an efficient carbonization layer, improves the flame-retardant efficiency, forms a chemical bond with magnesium hydroxide, effectively improves the interface bonding strength, forms a covalent anchoring layer through silanization treatment, gives the graphene surface an amino functional group, improves the compatibility with the polymer matrix, and produces a double flame-retardant network through starch phosphate ester compounding, improves the thermal stability of the carbon layer and prevents the carbon layer from collapsing, reduces the combustion dripping rate, and effectively reduces the graphene consumption. In addition, the modified graphene has a synergistic effect with nano-magnesium hydroxide and nano-sodium silicate, constructs a three-dimensional carbon layer-inorganic barrier composite system, and further improves the flame-retardant effect. DETAILED DESCRIPTION

[0021] In order to further illustrate the technical means and effects adopted by the application to achieve the predetermined application purpose, the specific embodiments, structures, features and effects according to the application are described in detail below in combination with examples.

[0022] In the examples and comparative examples of the application: Graphene oxide: purchased from Anhui Kelun Nanometer Technology Co., Ltd.; Ammonium dihydrogen phosphate: purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; Ammonia water: purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; γ-Aminopropyl triethoxysilane: purchased from Danyang Organic Silicon Material Industry Co., Ltd.; Starch phosphate ester: purchased from Nanjing Songguan Biological Technology Co., Ltd.; Sodium dodecyl benzene sulfonate: purchased from Shandong Hengli Auxiliary Co., Ltd.; Sodium fatty alcohol polyoxyethylene ether sulfate: purchased from Hubei Maikes Fine Chemical Technology Co., Ltd.; Nano-magnesium hydroxide: purchased from Wuhan Lvjingfenghua Biological Technology Co., Ltd.; Nano-sodium silicate: purchased from Chengdu Wuyi Sodium Silicate Factory.

[0023] Example 1 An environmentally friendly water-based composite flame retardant, the formula of the environmentally friendly water-based composite flame retardant is as follows, in terms of weight percentage, modified graphene 2%, nano-magnesium hydroxide 10%, nano-sodium silicate 6%, sodium dodecyl benzene sulfonate 0.8%, and the balance is deionized water; The preparation method of the modified graphene is as follows, S1-1: 100 parts by weight of a graphene oxide dispersion solution with a mass fraction of 4% is ultrasonically dispersed for 45 min, 7 parts by weight of ammonium dihydrogen phosphate is added, the pH is adjusted to 9.2 with ammonia water with a concentration of 1 M, stirring is carried out at 75 ℃ and a rotating speed of 550 r / min for 6 h, washing is carried out with deionized water until the pH of the solution is 7.0, and the dispersion solution A with a solid-liquid mass ratio of 1:100 is obtained by re-dispersing in deionized water. S1-2: 7% of the mass of the dispersion liquid A γ-aminopropyl triethoxysilane is added to the dispersion liquid A, the pH is adjusted to 5.5 using 0.5 M acetic acid, stirring at 55°C at a speed of 350 r / min for 2.5 h, washed with anhydrous ethanol, and freeze-dried at -40°C for 12 h to obtain powder B; S1-3: powder B is mixed with starch phosphate in a mass ratio of 5:1, placed in a ball mill and ball milled for 1.5 h at a speed of 120 r / min to obtain the modified graphene.

[0024] A preparation method of an environmentally friendly water-based composite flame retardant, the specific steps of the preparation method are as follows, S7-1: according to the formula, mix nano-magnesium hydroxide, nano-sodium silicate and deionized water and add to a high shear emulsification pump for high speed shearing for 40 min at a speed of 16000 rpm and a temperature of 35°C to obtain a mixed liquid C; S7-2: the mixed liquid C is subjected to electric field treatment at a voltage of 2000V for 12 min, and then is left to stand for 24 h to obtain a mixed liquid D; S7-3: the modified graphene and sodium dodecyl benzene sulfonate are sequentially added to the mixed liquid D, and stirring is carried out at 80°C for 1.5 h at a stirring speed of 900 rpm to obtain the composite flame retardant.

[0025] The application of an environmentally friendly water-based composite flame retardant, the composite flame retardant is applied to the field of fire extinguishing, the composite flame retardant is mixed with deionized water in a volume ratio of 1:10 to obtain a composite flame retardant diluent, which is directly used for jet fire extinguishing.

[0026] Example 2 An environmentally friendly water-based composite flame retardant, the formula of the environmentally friendly water-based composite flame retardant is as follows, in terms of weight percentage, modified graphene 1.5%, nano-magnesium hydroxide 8%, nano-sodium silicate 5%, fatty alcohol polyoxyethylene ether sodium sulfate 0.5%, and the balance is deionized water; The preparation method of the modified graphene is as follows, S1-1: 100 parts by weight of a 3% mass fraction of graphene oxide dispersion liquid is ultrasonically dispersed for 30 min, 5 parts by weight of ammonium dihydrogen phosphate is added, the pH is adjusted to 9.0 using 1 M ammonia water, stirring is carried out at 70°C at a speed of 500 r / min for 4 h, the solution is washed with deionized water until the pH is 7.0, and then is redispersed in deionized water to obtain a dispersion liquid A with a solid-liquid mass ratio of 1:100; S1-2: 5% of the dispersion liquid A mass of γ-aminopropyl triethoxysilane is added to the dispersion liquid A, the pH is adjusted to 5.0 by using 0.5 M acetic acid, stirring at 300 r / min at 50℃ for 2h, washing with anhydrous ethanol, and freeze-drying at -40℃ for 12h to obtain powder B; S1-3: powder B is mixed with starch phosphate in a mass ratio of 4:1, placed in a ball mill for ball milling for 1h at a ball milling speed of 100 r / min to obtain the modified graphene.

[0027] A preparation method of an environmentally friendly water-based composite flame retardant, the specific steps of the preparation method are as follows, 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 a mixed liquid C; S7-2: the mixed liquid C is subjected to electric field treatment at a voltage of 2000V for 10 min, and then is left to stand for 24h to obtain a mixed liquid D; S7-3: the modified graphene and sodium fatty alcohol polyoxyethylene ether sulfate are sequentially added to the mixed liquid D, and stirring is carried out at 80℃ for 1h at a stirring speed of 800 rpm to obtain the composite flame retardant.

[0028] An application of an environmentally friendly water-based composite flame retardant, the composite flame retardant is applied to the field of fire extinguishing, the composite flame retardant is mixed with deionized water in a volume ratio of 1:10 to obtain a composite flame retardant diluent, and the composite flame retardant diluent is directly used for jet fire extinguishing.

[0029] Example 3 An environmentally friendly water-based composite flame retardant, the formula of the environmentally friendly water-based composite flame retardant is as follows, in terms of weight percentage, modified graphene 3.0%, nano-magnesium hydroxide 12%, nano-sodium silicate 8%, sodium dodecyl benzene sulfonate 1.0%, and the balance is deionized water; The preparation method of the modified graphene is as follows, S1-1: 100 parts by weight of a 5% mass fraction of graphene oxide dispersion liquid is ultrasonically dispersed for 60 min, 10 parts by weight of ammonium dihydrogen phosphate is added, the pH is adjusted to 9.5 by using 1 M ammonia water, stirring is carried out at 600 r / min at 80℃ for 8h, washing is carried out with deionized water until the pH of the solution is 7.0, and then the dispersion liquid A with a solid-liquid mass ratio of 1:100 is obtained by re-dispersing in deionized water. S1-2: 5-10% of the mass of dispersion A of γ-aminopropyl triethoxysilane is added to dispersion A, the pH is adjusted to 6.0 by using 0.5 M acetic acid, stirring is carried out at 60°C and a rotation speed of 400 r / min for 3 h, washing is carried out by using anhydrous ethanol, and freezing drying is carried out at -40°C for 12 h to obtain powder B; S1-3: powder B is mixed with starch phosphate at a mass ratio of 6:1, ball milling is carried out in a ball mill at a rotation speed of 150 r / min for 2 h to obtain the modified graphene.

[0030] A preparation method of an environmentally friendly water-based composite flame retardant, the specific steps of the preparation method are as follows, S7-1: nano-magnesium hydroxide, nano-sodium silicate and deionized water are mixed according to the formula and added to a high-shear emulsification pump for high-speed shearing for 50 min at a rotation speed of 17000 rpm and a temperature of 40°C to obtain a mixed solution C; S7-2: the mixed solution C is subjected to electric field treatment at a voltage of 2000 V for 15 min, and then is left to stand for 24 h to obtain a mixed solution D; S7-3: the modified graphene and the surfactant are sequentially added to the mixed solution D, stirring is carried out at 80°C for 2 h at a rotation speed of 1000 rpm to obtain the composite flame retardant.

[0031] An application of an environmentally friendly water-based composite flame retardant, the composite flame retardant is applied to the field of fire extinguishing, the composite flame retardant is mixed with deionized water at a volume ratio of 1:10 to obtain a composite flame retardant diluent, and the composite flame retardant diluent is directly used for jetting fire extinguishing.

[0032] Comparative Example 1 In the preparation of the modified graphene, no ammonium dihydrogen phosphate is added, and the remaining steps are consistent with those of Example 1.

[0033] Comparative Example 2 In the preparation of the modified graphene, no starch phosphate is added, and the remaining steps are consistent with those of Example 1.

[0034] Comparative Example 3 The graphene oxide is not modified, and the remaining steps are consistent with those of Example 1.

[0035] Comparative Example 4 No modified graphene oxide is added, and the remaining steps are consistent with those of Example 1.

[0036] Comparative Example 5 In the preparation of the modified graphene, no γ-aminopropyl triethoxysilane is added, and the remaining steps are consistent with those of Example 1.

[0037] Comparative Example 6 The remaining steps are consistent with Example 1 without adding nano-magnesium hydroxide.

[0038] Comparative Example 7 The remaining steps are consistent with Example 1 without adding nano-sodium silicate.

[0039] Flame-retardant performance test The limiting oxygen index of the flame retardants prepared in the examples and comparative examples is tested according to the GB / T 2406.2-2009 standard, and the experimental results are recorded in the following table.

[0040] As can be seen from the data of the examples and comparative examples, the flame retardant prepared in the present application has good flame-retardant effect.

[0041] The above is only a preferred embodiment of the present application, and does not limit the present application in any form. Although the present application has been disclosed as above with a preferred embodiment, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to the above disclosed technical content without departing from the scope of the technical solution of the present application, and any simple modification, equivalent change and modification of the above examples according to the technical essence of the present application are still within the scope of the technical solution of the present application.

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 environment-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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