Fire extinguishing agent and preparation method and application thereof

Abstract

The invention relates to the technical field of fire-fighting materials, in particular to a fire extinguishing agent and a preparation method and application thereof. The fire extinguishing agent comprises the following components in percentage by mass: 0.5%-5% of graphene oxide, 10%-25% of a gel matrix, 5%-15% of ammonium polyphosphate, 1%-3% of lauryl sodium sulfate, 2%-8% of zinc borate, 3%-10% of bentonite and the balance of water. According to the fire extinguishing agent, graphene oxide is innovatively introduced and combined with multiple functional components, the fire extinguishing efficiency is remarkably improved, the temperature of a fire scene can be rapidly reduced through high thermal conductivity, free radicals can be effectively adsorbed through the super-large specific surface area, a compact barrier layer is formed, oxygen is isolated, and therefore the reburning rate is greatly reduced to 8% or below.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fire-fighting materials, in particular to a fire extinguishing agent and a preparation method and application thereof. BACKGROUND

[0002] Forest fire is a kind of extremely destructive natural disaster, which has the characteristics of fast spreading speed, high rekindling rate and difficult to put out, and poses a serious threat to the ecological environment, human life and property safety and social and economic stability. With the global warming and continuous development of forest resources, the frequency and scale of forest fires are on the rise, therefore, it is particularly important to develop efficient, environmentally friendly and reliable forest fire-fighting technology and equipment.

[0003] The traditional forest fire-fighting methods mainly rely on manual extinguishing, fire truck water spraying, dry powder extinguishing agent, foam extinguishing agent and aerosol extinguishing agent, etc. However, these traditional extinguishing means have many limitations in dealing with forest fires: (1) Dry powder extinguishing agent: Although the dry powder extinguishing agent has the advantages of fast extinguishing speed and easy to use, it has obvious defects in forest fires. The dry powder extinguishing agent is easily affected by air flow, difficult to cover the fire source uniformly, only can extinguish the surface flame, ineffective for deep smoldering, and the extinguishing effect is greatly discounted in strong wind environment, difficult to effectively control the spread of fire.

[0004] (2) Water-based extinguishing agent: The water-based extinguishing agent has significant cooling effect, but its adhesion is poor, difficult to adhere to the surface of the burning material for a long time, cannot effectively isolate oxygen, resulting in high rekindling rate after extinguishing. In addition, the water-based extinguishing agent is easy to freeze in low temperature environment, affecting its normal use, and large-scale use of water-based extinguishing agent may cause certain water and soil erosion and ecological damage to the forest soil and vegetation.

[0005] (3) Foam extinguishing agent: The foam extinguishing agent has certain heat and oxygen isolation effect, but it has problems such as foam being blown away by wind, limited coverage, poor adaptability to tall trees and complex terrain, and the composition of the foam extinguishing agent may pollute the forest ecosystem.

[0006] (4) Aerosol extinguishing agent: The aerosol extinguishing agent releases inert gas to reduce the oxygen concentration in the fire field, so as to achieve the purpose of extinguishing. However, the cost of aerosol extinguishing agent is high, and it may cause certain pollution to the environment during release, at the same time, its extinguishing efficiency is relatively low, difficult to meet the extinguishing demand of large-scale forest fires.

[0007] In summary, the existing forest fire-fighting technology and equipment still have many shortcomings in dealing with complex fire conditions, and it is urgent to develop a new type of forest fire bomb extinguishing agent to overcome the defects of traditional extinguishing agents, improve the extinguishing efficiency, reduce the rekindling rate, and achieve the environmentally friendly and non-toxic extinguishing effect. SUMMARY

[0008] The present application provides a fire extinguishing agent and its preparation method and application to solve the problems of uneven coverage, poor wind resistance, and inability to suppress hidden fires of traditional forest fire extinguishing agents.

[0009] According to the first aspect of the present application, the present application provides a fire extinguishing agent, comprising the following components by mass percentage: graphene oxide 0.5%-5%, gel matrix 10%-25%, ammonium polyphosphate (APP) 5%-15%, sodium dodecyl sulfate (SDS) 1%-3%, zinc borate 2%-8%, bentonite 3%-10%, and water in the balance.

[0010] The fire extinguishing agent of the present application is formed by reasonably matching graphene oxide, gel matrix, ammonium polyphosphate, sodium dodecyl sulfate, zinc borate, bentonite, and water, and each component synergistically forms a fire extinguishing agent with excellent comprehensive performance. Among them, the high thermal conductivity of graphene oxide can accelerate the heat diffusion of the fire scene, achieving rapid cooling; its large specific surface area can adsorb free radicals and form a dense barrier layer, effectively isolating oxygen, inhibiting the spread of fire, and reducing the rekindling rate. The gel matrix gives the fire extinguishing agent good adhesion and stability, so that the fire extinguishing agent can adhere to the surface of the burning object for a long time, enhancing the fire extinguishing effect. Ammonium polyphosphate catalyzes the formation of carbon and releases flame-retardant gas when heated, further improving the fire extinguishing efficiency. Sodium dodecyl sulfate as a dispersing agent ensures the uniform distribution of graphene oxide in the fire extinguishing agent, so that it can exert its best performance. Zinc borate can inhibit smoldering and reduce the risk of rekindling. Bentonite plays a role in thickening and suspending, improving the physical properties of the fire extinguishing agent, making it more suitable for application scenarios of fire extinguishing bombs. Water as a solvent adjusts the viscosity and fluidity of the fire extinguishing agent, making it easy to spray and cover. The fire extinguishing agent of the present application applied in forest fire extinguishing shows excellent performance in coverage area, rekindling rate, and thermal stability.

[0011] Further, the number of layers of graphene oxide is 1-10 layers, and the thickness of graphene oxide is 1-5 nm; by precisely controlling the number of layers and thickness of graphene oxide, the present application makes it form a better synergistic effect with other components, quickly conducts heat, efficiently adsorbs free radicals, and forms a dense oxygen barrier layer in the fire extinguishing agent, thereby reducing the forest fire rekindling rate to below 8%.

[0012] Preferably, the number of layers of graphene oxide is 2-3 layers, and the thickness of graphene oxide is 2-3 nm. The above scheme further limits the specific properties of graphene oxide, which helps to more accurately control the effect of graphene oxide in the fire extinguishing agent, ensuring that it can exert its best performance in heat conduction, free radical adsorption, and barrier layer formation, thereby further improving the overall fire extinguishing efficiency of the fire extinguishing agent.

[0013] Further, the particle size of the graphene oxide is concentrated in 1-20 μm. By limiting the particle size of the graphene oxide to be concentrated in 1-20 μm, it is uniformly dispersed in the fire extinguishing agent and quickly builds a dense oxygen barrier layer, thereby greatly improving the fire extinguishing coverage efficiency and reducing the risk of reignition.

[0014] Preferably, the D10 of the graphene oxide is 1-2 μm, the D50 is 3.5-5 μm, the D90 is 10-11 μm, and the particle size distribution index PDI=(D90-D10) / D50 satisfies: PDI≤2.5. By precisely controlling the particle size of the graphene oxide in the narrow distribution interval of D50≈4 μm, PDI≤2.5, it is uniformly dispersed in the fire extinguishing agent and forms a dense and efficient oxygen barrier layer, thereby significantly improving the fire extinguishing coverage rate and the flame retardant stability.

[0015] The above scheme further limits the specific properties of the graphene oxide, which helps to more accurately control the effect of the graphene oxide in the fire extinguishing agent and ensure that it plays the best performance in heat conduction, free radical adsorption and barrier layer formation, thereby further improving the overall fire extinguishing efficiency of the fire extinguishing agent.

[0016] Preferably, the D10 of the graphene oxide is 1.5-1.8 μm, the D50 is 4-4.5 μm, the D90 is 10-10.6 μm, and the particle size distribution index PDI=(D90-D10) / D50 satisfies: PDI≤2.2.

[0017] In some specific embodiments, the D10 of the graphene oxide is 1.655 μm, the D50 is 4.131 μm, the D90 is 10.48 μm, and the particle size distribution index PDI=(D90-D10) / D50 satisfies: PDI=2.136.

[0018] Further, the preparation method of the graphene oxide is based on the improved Hummers method, a mixed system of potassium dihydrogen phosphate and concentrated sulfuric acid is selected as the intercalation agent, potassium permanganate is used as the oxidizing agent, and the raw material dosage is optimized, and the GO is prepared under the condition of external force such as stirrer.

[0019] Further, the preparation method of the graphene oxide comprises the following steps: (1) The concentrated sulfuric acid and the potassium dihydrogen phosphate are stirred and mixed, and the intercalation agent required for the reaction is obtained after stirring uniformly.

[0020] (2) The flaky graphite is slowly added to the mixed reagent, and an electric stirrer is used for stirring.

[0021] (3) After stirring for 20-40 min, the beaker is placed in an ice water bath at a temperature of no more than 25°C, and potassium permanganate is slowly added and stirred for 10-30 min. Then the stirred mixture dispersion is placed in a constant temperature water bath at 30-50°C and stirred for 1-2 h to obtain a brown dispersion.

[0022] (4) Hydrogen peroxide is added and stirred to remove unreacted potassium permanganate. When no gas bubbles are generated in the reaction, stirring is stopped, and at this time the dispersion is yellow.

[0023] (5) The obtained dispersion is ultrasonically treated for 20-40 min to fully exfoliate the graphite oxide. After the slurry is uniformly dispersed, it is placed in a homogenizer for homogenization.

[0024] (6) Hydrochloric acid aqueous solution is added to the ultrasonically treated dispersion for acid washing to remove metal ions in the dispersion.

[0025] (7) The dispersion is then centrifuged. After centrifugation, the dispersion on the upper layer of the centrifugal tube is the graphene oxide dispersion.

[0026] (8) The obtained graphene oxide dispersion is first suction filtered, and the graphene oxide filter cake after suction filtration is freeze-dried to obtain graphene oxide powder.

[0027] Preferably, in step (1), the volume to mass ratio of concentrated sulfuric acid to potassium dihydrogen phosphate is (80-120) mL:(8-12) g. The mixing time is 5-15 min.

[0028] Preferably, in step (2), the weight ratio of potassium dihydrogen phosphate to flake graphite is (8-12):(3-5).

[0029] Preferably, in step (3), the weight ratio of flake graphite to potassium permanganate is (3-5):(4-6).

[0030] Preferably, in step (5), the homogenization is performed by controlling the pressure valve, and the working pressure is adjusted to 500-700 Bar, and the homogenization time is 60-100 min.

[0031] Preferably, in step (7), the rotation speed is 8000-12000 r / min, and the time is 20-40 min.

[0032] In some specific embodiments, the method for preparing graphene oxide is as follows: 100 mL of concentrated sulfuric acid and 10 g of potassium dihydrogen phosphate are stirred and mixed for 10 min to obtain an intercalating agent required for the reaction.

[0033] 4 g of flake graphite is slowly added to the mixed reagent, and an electric stirrer is used for stirring.

[0034] After 30 min, the beaker was placed in an ice water bath at no more than 25°C and 5 g of potassium permanganate was slowly added and stirred for 20 min, then the stirred mixture dispersion was placed in a constant temperature water bath at 40°C and stirred for another 1 h to obtain a brown dispersion.

[0035] 10 mL of hydrogen peroxide was added to remove the unreacted potassium permanganate, and the stirring was stopped when no bubbles were generated in the reaction, at which time the dispersion was yellow.

[0036] The obtained dispersion was ultrasonicated for 30 min to fully exfoliate the graphite oxide. After the slurry was uniformly dispersed, it was placed in a homogenizer to control the pressure valve, and the working pressure was adjusted to 600 Bar, and the homogenization time was 80 min, respectively.

[0037] 300 mL of 3% hydrochloric acid was added to the dispersion after ultrasonication for acid washing to remove metal ions in the dispersion.

[0038] The dispersion was then centrifuged at 10000 r / min for 30 min. After centrifugation, the dispersion on the upper layer of the centrifuge tube was the graphene oxide dispersion.

[0039] The obtained graphene oxide dispersion was first filtered, and the filtered graphene oxide cake was freeze-dried for 72 h to obtain graphene oxide powder.

[0040] Further, the gel matrix is sodium polyacrylate; preferably, the molecular weight of the sodium polyacrylate is 1500-3000. Sodium polyacrylate has good water absorption and gel-forming properties, can form a stable gel structure, and endows the fire extinguishing agent with excellent adhesion and stability. By controlling the molecular weight of sodium polyacrylate, the strength and viscosity of the gel can be adjusted to better meet the application requirements of the fire extinguishing bomb, ensuring that the fire extinguishing agent can uniformly cover the surface of the burning object after spraying and maintain effective coverage for a long time, thereby improving the fire extinguishing effect.

[0041] Further, it also includes: 0.4%-0.6% defoamer; preferably, the defoamer is a polydimethylsiloxane defoamer. The addition of a defoamer (preferably a polydimethylsiloxane defoamer) can effectively prevent the generation of excessive foam during the preparation and use of the fire extinguishing agent. Excessive foam may cause the stability of the fire extinguishing agent to decrease, affecting its uniformity and coverage effect. By adding an appropriate amount of defoamer, the homogenization process during the preparation of the fire extinguishing agent and the stable storage and spraying in the fire extinguishing bomb can be ensured, ensuring that the performance of the fire extinguishing agent is not affected by foam, thereby improving the reliability and efficiency of fire extinguishing.

[0042] Further, a pH regulator 0.4%-0.6% is further included; preferably, the pH of the fire extinguishing agent is neutral. The pH of the fire extinguishing agent is kept neutral (or close to neutral) by adding the pH regulator. The neutral fire extinguishing agent is environmentally friendly and does not cause acid-base pollution to the forest soil, vegetation and ecosystem. At the same time, the neutral environment helps to maintain the stability of each component in the fire extinguishing agent, ensuring that its performance is not affected by the change of pH during storage and use, thereby ensuring the fire extinguishing effect and safety of the fire extinguishing agent.

[0043] Preferably, a fire extinguishing agent includes the following components by mass percentage: graphene oxide 4%-5%, gel matrix 20%-25%, ammonium polyphosphate (APP) 10%-15%, sodium dodecyl sulfate (SDS) 2%-3%, zinc borate 7%-8%, bentonite 9%-10%, defoaming agent 0.4-0.6%, pH regulator 0.4-0.6%, and water in the balance.

[0044] More preferably, a fire extinguishing agent includes the following components by mass percentage: graphene oxide 4.5%-5%, gel matrix 23%-25%, ammonium polyphosphate (APP) 13%-15%, sodium dodecyl sulfate (SDS) 2.5%-3%, zinc borate 7.5%-8%, bentonite 9.5%-10%, defoaming agent 0.45-0.55%, pH regulator 0.45-0.55%, and water in the balance.

[0045] In some embodiments, a fire extinguishing agent includes the following components by mass percentage: graphene oxide 5%, gel matrix 25%, ammonium polyphosphate (APP) 15%, sodium dodecyl sulfate (SDS) 3%, zinc borate 8%, bentonite 10%, defoaming agent 0.5%, pH regulator 0.5%, and water in the balance.

[0046] According to a second aspect of the present application, the present application further provides a preparation method of the above-mentioned fire extinguishing agent, comprising the following steps: mixing graphene oxide with sodium dodecyl sulfate, ultrasonic dispersion, to obtain a GO suspension; dissolving the gel matrix in water, sequentially adding ammonium polyphosphate, zinc borate and bentonite, stirring until homogeneous, to obtain a homogeneous liquid; adding the GO suspension into the homogeneous liquid for homogenization treatment.

[0047] The preparation method of the present application prepares a uniform GO suspension by mixing graphene oxide with sodium dodecyl sulfate and then ultrasonic dispersion, and then mixes the GO suspension with a gel matrix and other components and performs homogenization treatment, thereby ensuring uniform distribution of the components in the fire extinguishing agent. This preparation method can fully utilize the performance of graphene oxide to form a uniform heat-conducting network and barrier layer in the fire extinguishing agent, thereby improving the heat-conducting performance and barrier effect of the fire extinguishing agent. Meanwhile, the uniform distribution of the components can also help the fire extinguishing agent to quickly form a stable covering layer after spraying, thereby enhancing the fire extinguishing effect.

[0048] Further, the ultrasonic dispersion frequency is 30-50 kHz, the power is 200-400 W, and the time is 20-40 min. By limiting the specific parameters of ultrasonic dispersion within a reasonable range, the best dispersion effect of graphene oxide during the dispersion process can be ensured. Suitable ultrasonic frequency and power can provide sufficient energy to fully disperse graphene oxide and avoid agglomeration, thereby better utilizing the role of graphene oxide in the fire extinguishing agent. Reasonable dispersion time ensures the sufficiency of the dispersion process, while avoiding excessive dispersion that may cause energy waste and damage to the structure of graphene oxide, thereby ensuring the performance stability and consistency of the fire extinguishing agent.

[0049] Further, during the preparation of the homogenate, the stirring speed is 800-1200 rpm, and the stirring time is 15-25 min.

[0050] Further, the stirring speed of the homogenization treatment is 1000-2000 rpm, and the stirring time is 15-25 min.

[0051] The above scheme further limits the specific conditions of the homogenate preparation process and the homogenization treatment, which helps to more accurately control the physical properties and stability of the fire extinguishing agent.

[0052] According to a third aspect of the present application, the present application also provides the use of the above-mentioned fire extinguishing agent or the fire extinguishing agent prepared by the above-mentioned preparation method in forest fire extinguishing bombs.

[0053] The fire extinguishing agent of the present application has the characteristics of rapid cooling, suppression of hidden fire, environmental protection, and non-toxicity by optimizing the formula and preparation process, and can effectively solve the problems of uneven coverage, poor wind resistance, and inability to suppress hidden fire of traditional forest fire extinguishing bomb fire extinguishing agents. The application of the fire extinguishing agent in forest fire extinguishing bombs can significantly improve the fire extinguishing efficiency and reduce the rekindling rate, thereby providing a new solution for efficient suppression of forest fires, and having important practical application value.

[0054] Preferably, an arc-shaped reflector is used in the application process.

[0055] The arc surface reflection plate is a key efficiency design of the forest fire extinguishing bomb, and through the physical orientation mechanism, the utilization rate of the fire extinguishing agent is increased to more than 4 times of the traditional bomb, the wind resistance is enhanced, the coverage range is expanded, and the unmanned aerial vehicle throwing demand is adapted.

[0056] The beneficial effects of the present application are as follows: The fire extinguishing agent provided by the present application significantly improves the fire extinguishing efficiency by innovatively introducing graphene oxide and combining a plurality of functional ingredients. The high thermal conductivity of the fire extinguishing agent can quickly reduce the temperature of the fire scene, the super large specific surface area can effectively adsorb free radicals and form a dense barrier layer to isolate oxygen, thereby greatly reducing the rekindling rate to below 8%. At the same time, the optimized formula and preparation process make the fire extinguishing agent have excellent adhesion, stability and wind resistance, and the coverage area is increased by more than 40% compared with traditional fire extinguishing agents, and the fire extinguishing agent is environmentally friendly and non-toxic. After adapting to the unmanned aerial vehicle bomb throwing system, the fire extinguishing agent can accurately cover the fire source, and is especially suitable for extinguishing tree crown fire, ground fire and flying fire and other complex fire conditions, thereby providing a new solution for efficient extinguishing of forest fires, and filling the technical blank of graphene in the field of forest fire extinguishing bombs. BRIEF DESCRIPTION OF DRAWINGS

[0057] In order to more clearly illustrate the technical solutions in the present application or prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0058] Figure 1 is an XRD pattern of graphene oxide used in the fire extinguishing agent provided by the embodiments of the present application.

[0059] Figure 2 is an AFM characterization diagram of graphene oxide used in the fire extinguishing agent provided by the embodiments of the present application; wherein (a) is a surface topography diagram; and (b) is an ab section line diagram.

[0060] Figure 3 is an SEM diagram of graphene oxide used in the fire extinguishing agent provided by the embodiments of the present application.

[0061] Figure 4 is a particle size distribution diagram of graphene oxide used in the fire extinguishing agent provided by the embodiments of the present application. DETAILED DESCRIPTION

[0062] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be clearly and completely described below. Obviously, the described embodiments are some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work belong to the protection scope of the present application.

[0063] The raw materials used in the following examples are as follows: Sodium polyacrylate: model TH888, produced by Shandong Peihao Biotechnology Co., Ltd., produced in Hangzhou, food grade, and executed standard GB29948.

[0064] Ammonium polyphosphate (APP): model FR-A02, produced by Jinan Boying Flame Retardant Material Co., Ltd., produced in Jinan, Shandong.

[0065] Sodium dodecyl sulfate (SDS): model 28312, produced by Thermo Fisher Scientific.

[0066] Zinc borate: item number XHL0447, produced by Hubei Xinhongli Chemical Co., Ltd.

[0067] Bentonite: GW-808, Wuhu Shuohua New Material Technology Co., Ltd.

[0068] Defoaming agent: pH value 6-8, produced by Henan Shunzhibang Environmental Protection Technology Co., Ltd.

[0069] pH regulator: model amp95, produced by Dow Angus.

[0070] The preparation method of graphene oxide is as follows: Stir and mix concentrated sulfuric acid and potassium dihydrogen phosphate at a ratio of 100 mL:10 g for 10 min, and obtain the intercalating agent required for the reaction after stirring uniformly.

[0071] Slowly add 4 g of flake graphite to the mixed reagent, and stir using an electric stirrer.

[0072] After 30 min, place the beaker in an ice water bath not higher than 25°C and slowly add 5 g of potassium permanganate and stir for 20 min, then place the stirred mixed dispersion in a constant temperature water bath at 40°C and stir for another 1 h to obtain a brown dispersion.

[0073] Add 10 mL of hydrogen peroxide and stir to remove unreacted potassium permanganate, and stop stirring when no bubbles are generated in the reaction. At this time, the dispersion is yellow.

[0074] The obtained dispersion liquid was ultrasonically treated for 30 min to make the graphite oxide sufficiently exfoliated. After the slurry was uniformly dispersed, it was put into a homogenizer to adjust the working pressure to 600 Bar through a pressure control valve, and the homogenization time was 80 min.

[0075] 300 mL of 3% hydrochloric acid aqueous solution was added to the ultrasonic dispersion liquid for acid washing to remove metal ions in the dispersion liquid.

[0076] The dispersion liquid was then centrifuged at a speed of 10000 r / min for 30 min. After centrifugation, the dispersion liquid on the upper layer of the centrifugal tube was the graphene oxide dispersion liquid.

[0077] The obtained graphene oxide dispersion liquid was first subjected to suction filtration, and the graphene oxide filter cake after suction filtration was freeze-dried for 72 h to obtain graphene oxide powder.

[0078] Characterization of graphene oxide (GO): as shown in Figure 1 , the diffraction peak appeared at 2θ = 11.6°, and the interlayer spacing d2 = 0.762 nm was obtained by using Bragg's equation. The interlayer spacing is obviously higher than that of flake graphite, indicating that the desired effect has been achieved in the process of exfoliating graphite oxide.

[0079] As shown in Figure 2 , the thickness of the graphene oxide prepared by this method is 2.67 nm, and according to the literature, the thickness of single-layer graphene oxide under atomic force characterization is 0.7-1.2 nm. Therefore, it can be roughly calculated that about 2-3 layers of graphene oxide can be prepared by this method.

[0080] As shown in Figure 3 , the maximum flake diameter of graphene oxide is about 10 μm and the surface is smooth, and obvious curling and wrinkling appears at the edge, which is caused by the epoxy groups on the surface and edge, which can effectively reduce the large surface energy of graphene oxide. This is conducive to the protection of the layered structure of graphene oxide.

[0081] As shown in Figure 4 , the laser particle size analyzer test shows that the particle size of graphene oxide is concentrated in the range of 1-20 microns. In the particle size distribution, D10 = 1.655, D50 = 4.131, D90 = 10.48, and the particle size distribution index PDI = (D90 - D10) / D50 = 2.136.

[0082] Example 1 This example provides a fire extinguishing agent, which comprises GO 0.5%, sodium polyacrylate 15%, APP 10%, SDS 1%, zinc borate 5%, bentonite 5%, and deionized water 63.5%.

[0083] The embodiment further provides a preparation method of the fire extinguishing agent, comprising the following steps: 1. GO is mixed with SDS, and ultrasonic dispersion (40 kHz, 300 W) is performed for 30 minutes to prepare a GO suspension.

[0084] 2. Sodium polyacrylate is dissolved in 60 DEG C deionized water, and APP, zinc borate and bentonite are sequentially added and stirred until homogeneous to obtain a homogeneous liquid; the stirring speed is 1000 rpm, and the stirring time is 15 min.

[0085] 3. The GO suspension is injected into the homogeneous liquid, and homogenization treatment is performed before filling; the stirring speed of the homogenization treatment is 1500 rpm, and the stirring time is 20 min.

[0086] Example 2 The embodiment provides a fire extinguishing agent, which comprises GO 2%, sodium polyacrylate 20%, APP 12%, SDS 2%, zinc borate 6%, bentonite 8% and deionized water 50%.

[0087] The embodiment further provides a preparation method of the fire extinguishing agent, which is different from that of the example 1 in that the stirring speed of the homogenization treatment in step 3 is 2000 rpm.

[0088] Example 3 The embodiment provides a fire extinguishing agent, which comprises GO 5%, sodium polyacrylate 25%, APP 15%, SDS 3%, zinc borate 8%, bentonite 10%, polydimethylsiloxane defoaming agent 0.5%, pH regulator ammonia water 0.5% and deionized water in a residual amount. The pH value of the fire extinguishing agent is 7.0.

[0089] The embodiment further provides a preparation method of the fire extinguishing agent, comprising the following steps: 1. GO is mixed with SDS, and ultrasonic dispersion (40 kHz, 300 W) is performed for 30 minutes to prepare a GO suspension.

[0090] 2. Sodium polyacrylate is dissolved in 60 DEG C deionized water, and APP, zinc borate, bentonite, polydimethylsiloxane defoaming agent and ammonia water are sequentially added and stirred until homogeneous to obtain a homogeneous liquid; the stirring speed is 1000 rpm, and the stirring time is 15 min.

[0091] 3. The GO suspension is injected into the homogeneous liquid, and homogenization treatment is performed before filling; the stirring speed of the homogenization treatment is 1500 rpm, and the stirring time is 20 min.

[0092] Comparative Example 1 The comparative example provides a fire extinguishing agent, which is composed of water 82.3%, diammonium phosphate 15%, polyacrylamide 0.5%, guar gum 0.1%, preservative 0.1%, and iron oxide red 2%.

[0093] The fire extinguishing agents of the examples and the comparative example are filled into hand-throwing fire extinguishing bombs for testing, and the application test results obtained are shown in Table 1. In the following performance indicators, the test methods of the coverage area, the afterglow rate and the thermal stability are as follows: (1) Coverage area: quantifying the effective diffusion coverage ability of a unit mass of fire extinguishing agent in a simulated fire field, measuring the boundary of the area where there is no open fire and the carbonization is uniform on the fuel bed surface after extinguishing the fire, calculating the area, and the coverage area (m 2 / g) = effective coverage area (m 2 ) / fire extinguishing agent mass (g).

[0094] (2) Afterglow rate: evaluating the probability of afterglow combustion after extinguishing the fire, reflecting the sustained fire retardant ability of the fire extinguishing agent, and the afterglow rate (%) = (afterglow times / total test times) x 100%.

[0095] (3) Thermal stability: determining the thermal decomposition behavior of the components of the fire extinguishing agent by thermal analysis technology, and characterizing the failure threshold at high temperature.

[0096] Table 1

[0097] As can be seen from the comparative experimental data in Table 1, the fire extinguishing agent of the present application is significantly superior to the traditional fire extinguishing agent in the three key performance indicators of coverage area, afterglow rate and thermal stability. In particular, the fire extinguishing agent of Example 3, on the basis of increasing the content of graphene oxide, adds a defoaming agent and a pH adjuster, further optimizes the process stability and component compatibility, so that better synergistic effect is formed between the components, the performance of the fire extinguishing agent is further improved, and the great application potential in the field of forest fire extinguishing is shown. The fire extinguishing agent of the present application can effectively solve the problems of uneven coverage, poor wind resistance and inability to suppress hidden combustion of the traditional fire extinguishing agent, and provides a new solution for efficient extinguishing of forest fires.

[0098] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, and are not limiting; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can modify the technical solutions recorded in the foregoing examples, or make equivalent substitutions for part of the technical features; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A fire extinguishing agent, characterized by, By mass percentage, the following components are included: graphene oxide 0.5%-5%, gel matrix 10%-25%, ammonium polyphosphate 5%-15%, sodium dodecyl sulfate 1%-3%, zinc borate 2%-8%, bentonite 3%-10%, and water in balance.

2. The fire extinguishing agent according to claim 1, characterized by The number of layers of the graphene oxide is 1-10, and the thickness of the graphene oxide is 1-5 nm. Preferably, the number of layers of the graphene oxide is 2-3, and the thickness of the graphene oxide is 2-3 nm.

3. The extinguishing agent according to claim 1 or 2, characterized in that, The particle size of the graphene oxide is concentrated in 1-20 μm. Preferably, the D10 of the graphene oxide is 1-2 μm, the D50 is 3.5-5 μm, the D90 is 10-11 μm, and the particle size distribution index PDI=(D90-D10) / D50 satisfies: PDI≤2.

5.

4. The fire extinguishing agent according to any one of claims 1 to 3, characterized in that, The preparation method of the graphene oxide uses a mixed system of potassium dihydrogen phosphate and concentrated sulfuric acid as an intercalating agent, and potassium permanganate as an oxidizing agent.

5. The fire extinguishing agent according to claim 1, characterized by, The gel matrix is sodium polyacrylate; preferably, the viscosity-average molecular weight of the sodium polyacrylate is 1500-3000. And / or, the fire extinguishing agent further includes: a defoaming agent 0.4%-0.6%; preferably, the defoaming agent is a polydimethylsiloxane defoaming agent; And / or, the fire extinguishing agent further includes a pH adjusting agent 0.4%-0.6%; preferably, the pH of the fire extinguishing agent is neutral.

6. A process for the preparation of a fire extinguishing agent as claimed in any one of claims 1 to 5, characterized in that The method includes the following steps: Mixing the graphene oxide with sodium dodecyl sulfate, ultrasonic dispersion, and preparing a GO suspension; Dissolving the gel matrix in water, sequentially adding ammonium polyphosphate, zinc borate, and bentonite, stirring until homogeneous, and obtaining a homogeneous liquid; Adding the GO suspension to the homogeneous liquid for homogenization treatment.

7. The preparation method according to claim 6, characterized in that, The frequency of the ultrasonic dispersion is 30-50 kHz, the power is 200-400 W, and the time is 20-40 min.

8. The preparation method according to claim 6, characterized in that, During the preparation of the homogeneous liquid, the stirring speed is 800-1200 rpm, and the stirring time is 10-20 min.

9. The preparation method according to claim 6, characterized in that, The stirring speed of the homogenization treatment is 1000-2000 rpm, and the stirring time is 15-25 min.

10. The fire extinguishing agent of any one of claims 1-5 or prepared by the preparation method of any one of claims 6-9 for use in forest fire extinguishing bombs.

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