Fire extinguishing agent for microgravity environment, preparation method and control method

Abstract

The invention discloses a fire extinguishing agent for a microgravity environment, a preparation method and a control method, the fire extinguishing agent is a three-stage composite system of a magnetic core, a CO2 phase change shell and a siloxane matrix, the magnetic core is used for moving the fire extinguishing agent, and the fire extinguishing agent is guided to a fire source in a controllable gradient magnetic field; the CO2 phase change shell can release supercritical CO2 at a specified point, the temperature of a fire source is reduced to be lower than the ignition point at the speed of 25 DEG C / s through phase change heat absorption, the rapid fire extinguishing effect is achieved, further, when the temperature of a siloxane matrix serving as a framework is larger than or equal to 300 DEG C, dehydration condensation reaction occurs, silicon dioxide nano-particles with the particle size being 5-10 nm are generated, the silicon dioxide nano-particles are naturally assembled to form the porous aerogel, and the porous aerogel is prepared. According to the invention, efficient scattering of heat radiation is realized, a heat insulation barrier with a thickness of 50-150 [mu] m is formed, contact between the heat radiation and oxygen is blocked, and finally, an integrated function of magnetic control guiding, temperature response release and heat insulation film forming is realized through collaborative design of functional components.

Description

Technical Field

[0001] The present invention relates to the field of aerospace fire safety and materials engineering technology, and in particular to a fire extinguishing agent for use in a microgravity environment, a preparation method and a control method. Background Art

[0002] During the extraterrestrial flight, the spacecraft has a fire safety function inside the cabin. -6 In a microgravity environment, flames spread in a spherical shape, and the disappearance of heat convection leads to oxygen-dependent molecular diffusion (at a rate of only 1 / 10 of that on the ground), which prolongs the combustion duration by 3-5 times. Existing safety firefighting systems include inert gas fire extinguishing, traditional magnetic particle fire extinguishing agents, and phase change material fire extinguishing agents. Inert gas fire extinguishing reduces the oxygen concentration in the cabin and releases inert gas to the fire source, while traditional magnetic particle fire extinguishing agents are mixed with magnetic particles on the basis of traditional fire extinguishing agents. The traditional magnetic particle fire extinguishing agents are adsorbed by permanent magnets and directed to the permanent magnets. Finally, the phase change material fire extinguishing agent contacts the high temperature at the fire source, triggering the phase change of the material and releasing the internal fire extinguishing agent to extinguish the fire.

[0003] However, traditional magnetic particle fire extinguishing agents are adsorbed by permanent magnets and have no temperature trigger mechanism. They are easily released by mistake in low-temperature areas, causing fire extinguishing failure. In addition, the residues are pure magnetic particles with no heat insulation ability and a high re-ignition rate. Summary of the Invention

[0004] In view of the above-mentioned defects or deficiencies in the prior art, it is desired to provide a fire extinguishing agent for use in a microgravity environment, a preparation method, and a control method.

[0005] In a first aspect, the present invention provides a fire extinguishing agent for use in a microgravity environment, comprising:

[0006] Magnetic core, content is 20-25 parts;

[0007] CO2 phase change shell, content is 10-15 parts;

[0008] Silicone matrix, content is 60-70 parts;

[0009] Functional additives, content is 1-5 parts;

[0010] The silicone matrix is ​​a three-dimensional network of elastic colloids, the magnetic core is uniformly dispersed in the three-dimensional network of elastic colloids, the CO2 phase change shell is uniformly dispersed in the three-dimensional network of elastic colloids in the form of microcapsules, and the interior of the microcapsules is supercritical CO2, and the functional additive includes a temperature-sensitive coating wrapped around the outside of the CO2 phase change shell.

[0011] The functional additive further comprises a charge enhancer and a surfactant uniformly dispersed in the three-dimensional network elastic colloid, wherein the content of the charge enhancer is 1-3 parts, the content of the surfactant is 0.1-0.5 parts, and the content of the temperature sensitive coating is 1-2 parts.

[0012] Preferably, the magnetic core is Fe3O4 having a siloxane-philic -SiO-C bond grafted layer on the surface, the outer skin of the CO2 phase change shell is composed of PLGA, and the siloxane matrix is ​​PDMS and TEOS.

[0013] In a second aspect, the present invention provides a method for preparing a fire extinguishing agent for use in a microgravity environment, comprising the following steps:

[0014] S1. Mixing Fe3O4 nanoparticles and KH-570 at a mass ratio of 1:0.2 and adding the mixture to anhydrous ethanol to obtain a mixed solution;

[0015] S2, subjecting the mixed solution to ultrasonic dispersion treatment for 30 minutes, and then subjecting the mixture to reflux reaction for 2 hours to obtain a wet intermediate;

[0016] S3, centrifuging, washing and drying the wet intermediate to obtain Fe3O4 with a siloxane-philic -SiO-C bond grafted layer on the surface, also known as modified Fe3O4;

[0017] S4, dissolving PLGA in dichloromethane liquid to obtain a mixed liquid;

[0018] S5. Adding supercritical CO2 to the mixed liquid under supercritical conditions to form an oil-in-water emulsion;

[0019] S6. Under a supercritical state, the oil-in-water emulsion is stirred at a stirring rate of 1500 rpm, and the dichloromethane liquid is volatilized to obtain a CO2 phase change shell in a monodisperse microcapsule state;

[0020] S7, dispersing the CO2 phase change shell in a tetrahydrofuran solution containing poly (N-vinyl carbazole), volatilizing the solvent after ultrasonic treatment, and forming a poly (N-vinyl carbazole) coating on the surface of the microcapsule;

[0021] S8, dispersing the modified Fe3O4, charge enhancer and surfactant in the PDMS prepolymer at high speed for 20 minutes to obtain a transition product;

[0022] S9. Adding a CO2 phase change shell having a poly N-vinyl carbazole coating and TEOS to the transition product, cross-linking in stages under the catalysis of dibutyltin dilaurate to form a fire extinguishing agent.

[0023] Preferably, the staged cross-linking includes a first stage and a second stage, wherein the first stage is a prepolymerization treatment at a temperature of 50° C. for 2 hours, and the second stage is a curing treatment at a temperature of 85° C. for 12 hours.

[0024] In a third aspect, the present invention provides a method for controlling a fire extinguishing agent for use in a microgravity environment, comprising the following steps:

[0025] P1. When the fire detection module detects a fire source, the drive module controls the storage module to release the fire extinguishing agent;

[0026] P2, the driving module generates a controllable gradient magnetic field, and the fire extinguishing agent moves toward the fire source;

[0027] P3, the fire extinguishing agent reaches the fire source, releases supercritical CO2 and forms porous aerogel;

[0028] P4. After the fire is extinguished, the residues are recovered through the first recovery module and the second recovery module.

[0029] Preferably, in step P1, the driving module includes a plurality of solenoid electromagnetic coils evenly distributed on the inner wall of the spacecraft cabin, and an FPGA control submodule that can be programmed and control various electrical appliances.

[0030] Preferably, in step P1, the storage module includes a pressure vessel for storing the fire extinguishing agent, and a nozzle connected to the pressure vessel via a discharge pipe, and the discharge pipe is provided with a solenoid valve.

[0031] Preferably, in step P4, the first recovery module includes a recovery electromagnetic coil, an outer cylinder arranged outside the recovery electromagnetic coil, and a first recovery barrel accommodating the outer cylinder; the second recovery module includes a vacuum pump, the suction port of the vacuum pump is connected to a plurality of suction heads through a suction pipe, the air outlet of the vacuum pump is connected to the second recovery barrel through an air outlet pipe, and the second recovery barrel is provided with a filter near the end of the air outlet pipe.

[0032] Preferably, the fire detection module includes a thermal imager and a smoke sensor.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The fire extinguishing agent of the present invention is a three-level composite system of a magnetic core, a CO2 phase change shell and a siloxane matrix. The magnetic core is used to move the fire extinguishing agent and guide the fire extinguishing agent to the fire source in a controllable gradient magnetic field. The temperature-sensitive coating coated on the outside of the CO2 phase change shell shrinks at high temperature, so that the CO2 phase change shell can release supercritical CO2 at a specified point, and absorbs heat through phase change to reduce the fire source temperature to below the ignition point at a rate of 25°C / s, quickly suppressing the combustion chain reaction and achieving a rapid fire extinguishing effect. Furthermore, the siloxane matrix serving as the skeleton undergoes a dehydration condensation reaction when the temperature is ≥300°C, generating silica nanoparticles with a particle size of 5-10nm, which naturally assemble to form porous aerogels, achieving efficient scattering of thermal radiation (wavelength > 2μm) and a lower thermal conductivity, which is superior to traditional aerospace thermal insulation materials, forming a thermal insulation barrier with a thickness of 50-150μm, blocking the contact of thermal radiation with oxygen, and ultimately achieving the integrated functions of magnetic control guidance, temperature-responsive release and thermal insulation film formation through the coordinated design of functional components.

[0035] Furthermore, the driving module forms a magnetic field through evenly distributed solenoid electromagnetic coils when energized. When a fire source appears in the cabin, the current of the solenoid coils near the fire source increases, thereby increasing the magnetic field strength in this area, and the current of the solenoid coils away from the fire source decreases accordingly, thereby forming a gradient magnetic field with gradually increasing magnetic field strength from the surrounding area to the fire source, and ultimately achieving the function of guiding the fire extinguishing agent to move in a directional manner toward the fire source. Compared with the use of permanent magnets for attraction in the prior art, the controllable magnetic field is more convenient for directional fire extinguishing and effectively improves the fire extinguishing efficiency. In addition, a first recovery module and a second recovery module are provided for recovering the residues after fire extinguishing to avoid the residues causing chaos inside the cabin.

[0036] It should be understood that the contents described in the summary of the invention are not intended to limit the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0038] Figure 1 A schematic structural diagram of a fire extinguishing agent for use in a microgravity environment provided in an embodiment of the present application;

[0039] Figure 2 A schematic diagram of the layout of a drive module in a method for controlling a fire extinguishing agent in a microgravity environment provided in an embodiment of the present application;

[0040] Figure 3A schematic diagram of the movement of a fire extinguishing agent in a method for controlling a fire extinguishing agent in a microgravity environment provided in an embodiment of the present application;

[0041] Figure 4 This is a schematic structural diagram of a first recovery module in a method for controlling a fire extinguishing agent in a microgravity environment provided in an embodiment of the present application;

[0042] Figure 5 This is a structural schematic diagram of the second recovery module in a method for controlling a fire extinguishing agent in a microgravity environment provided in an embodiment of the present application.

[0043] Numbers in the figure: 1. Fire extinguishing agent particles; 11. Silicone matrix; 12. Temperature sensitive coating; 13. Magnetic core; 14. CO2 phase change shell; 15. Surfactant; 16. Charge enhancer; 21. Cabin; 22. Solenoid coil; 23. FPGA control submodule; 24. Fire detection module; 25. Pressure vessel; 26. Solenoid valve; 27. Nozzle; 3. First recovery module; 31. First recovery barrel; 32. Outer cylinder; 33. Recovery electromagnetic coil; 4. Second recovery module; 41. Second recovery barrel; 42. Filter; 43. Vacuum pump; 44. Suction head. DETAILED DESCRIPTION

[0044] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are intended only to illustrate the relevant invention and are not intended to limit the invention. It should also be noted that, for ease of description, only portions relevant to the invention are shown in the accompanying drawings.

[0045] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0046] Example 1

[0047] refer to Figure 1 , an embodiment of the present invention provides a fire extinguishing agent for use in a microgravity environment, comprising:

[0048] Magnetic core 13, content is 22 parts;

[0049] CO2 phase change shell 14, content is 12 parts;

[0050] Silicone matrix 11, content is 62 parts;

[0051] Functional additives, content is 4 parts;

[0052] The siloxane matrix 11 is a three-dimensional network of elastic colloids, the magnetic core 13 is uniformly dispersed in the three-dimensional network of elastic colloids, the CO2 phase change shell 14 is uniformly dispersed in the three-dimensional network of elastic colloids in the form of microcapsules, and the interior of the microcapsules is supercritical CO2. The functional additive includes a temperature-sensitive coating 12 wrapped around the CO2 phase change shell;

[0053] Among them, high temperature will cause the temperature sensitive coating 12 to shrink, the stress of the microcapsule skin of the CO2 phase change shell 14 will concentrate and rupture, thereby releasing the supercritical CO2 inside the microcapsule skin. The density of supercritical CO2 is 460kg / m 3 , between liquid and gas, supercritical CO2 absorbs heat through phase change, reducing the fire source temperature to below the ignition point at a rate of 25℃ / s, quickly suppressing the combustion chain reaction;

[0054] Furthermore, the siloxane matrix 11 undergoes a dehydration condensation reaction at a temperature ≥300°C, and the generated silica nanoparticles (particle size 5-10nm) self-assemble to form a porous aerogel with a porosity ≥90% and an average pore size of 20-50nm, achieving efficient scattering (scattering coefficient ≥100m 2 / kg), and the thermal conductivity of porous aerogel is as low as 0.012W / (m·K), which is superior to traditional aerospace thermal insulation materials (such as aerogel felt, with a thermal conductivity of 0.015W / (m·K)). It forms a thermal insulation barrier with a thickness of 50-150μm, blocking the contact of thermal radiation with oxygen, achieving the purpose of preventing re-ignition and improving fire extinguishing efficiency.

[0055] In some embodiments, the functional additive further comprises a charge enhancer and a surfactant uniformly dispersed in the three-dimensional network of elastic colloid;

[0056] The content of the charge enhancer is 2 parts. The use of carbon nanotubes can enhance electrostatic adsorption and optimize the fluidity and dispersibility of the colloid. This ratio can fully exert its role in enhancing electrostatic adsorption efficiency and optimizing the fluidity and dispersibility of the colloid without affecting other properties of the colloid due to excessive content.

[0057] The content of the surfactant is 0.5 parts, and the use of quaternary ammonium salt can reduce surface tension and promote spreading, improve the compatibility of the colloid with other ingredients, and the proportion is generally 0.5 parts. This ratio can significantly reduce the surface tension of the colloid and promote spreading;

[0058] The content of the temperature sensitive coating is 1.5 parts, and poly N-vinyl carbazole can be used to accurately control the release timing of supercritical CO2 and enhance the targeting of the fire extinguishing medium.

[0059] In some embodiments, the magnetic core 13 has a particle size of 60 nm and has good magnetic properties, avoiding the situation where the magnetic attraction is too low due to low magnetism. The outer skin thickness of the CO2 phase change shell 14 is 2 μm. At this thickness, the shell molecules are tightly arranged to build a solid physical barrier, which greatly hinders the penetration of small gas molecules. In addition, due to the short heat conduction path, the shell can absorb heat and transfer it to the interior in a very short time. Furthermore, it will not interfere with the wrapping and support of the silicone matrix 11 due to being too thick, nor will it break or deform during the colloid formation process due to being too thin, ensuring that the entire fire extinguishing agent system is stable during storage and transportation. The crosslinking density of the silicone matrix 11 is 1.1 mmol / cm 3 , and the porosity is 60%.

[0060] In some embodiments, the magnetic core 13 is Fe3O4 with a siloxane-philic -SiO-C bond grafted layer on the surface, the outer skin of the CO2 phase change shell 14 is composed of PLGA, and the siloxane matrix 11 is PDMS and TEOS;

[0061] PDMS stands for Polydimethylsiloxane, and TEOS stands for Tetraethylorthosilicate. After pre-polymerization and cross-linking, PDMS and TEOS can form a three-dimensional network of elastic colloids as a skeleton, which is convenient for encapsulating components such as the magnetic core13 and the CO2 phase change shell14, providing support and stability for the entire system.

[0062] Furthermore, the full name of PLGA is poly (lactic-co-glycolic acid), and its Chinese name is polylactic acid-glycolic acid copolymer, which is formed by random polymerization of lactic acid and glycolic acid, which is wrapped outside supercritical CO2 to form a CO2 phase change shell 14 in the form of a microcapsule. PLGA and Fe3O4 with a siloxane-philic -SiO-C bond grafted layer are more easily connected to the siloxane matrix, and then wrapped in a three-dimensional network of elastic colloids. In addition, PLGA is the outer skin of the CO2 phase change shell 14.

[0063] Example 2

[0064] Based on Example 1, an embodiment of the present invention provides a method for preparing a fire extinguishing agent for use in a microgravity environment, which specifically includes the following steps:

[0065] S1. Mixing Fe3O4 nanoparticles and KH-570 at a mass ratio of 1:0.2 and adding the mixture to anhydrous ethanol to obtain a mixed solution; wherein, optionally, after the Fe3O4 nanoparticles and KH-570 are mixed, 5-10 ml of anhydrous ethanol is corresponding to each gram of the mixed solid to ensure that the mixed solid is fully mixed and to avoid excessive ethanol content in the sewage;

[0066] S2. Ultrasonic dispersion of the mixed solution for 30 minutes, followed by reflux reaction for 2 hours to obtain a wet intermediate; wherein ultrasonic dispersion utilizes the physical effect of ultrasound in a liquid to achieve particle dispersion, deagglomeration, or reaction promotion; further, reflux reaction refers to a process in which the vapor of the reaction mixture is cooled by a condenser under heating conditions and then flows back into the reaction system to maintain the reaction temperature and solvent concentration, thereby ultimately grafting the KH-570 silane coupling agent onto the surface of the Fe3O4 nanoparticles;

[0067] S3. The wetted intermediate is centrifuged, washed, and dried to obtain Fe3O3 with a siloxane-philic -SiO-C bond grafted layer on the surface, also known as modified Fe3O4; wherein, the centrifugal treatment is to achieve solid-liquid separation by means of centrifugal force. In this process, the liquid phase containing unreacted KH-570, reaction by-products, and anhydrous ethanol as a solvent is thrown to the outside of the centrifuge tube under the action of centrifugal force, while the Fe3O4 nanoparticles with -SiO-C bonds grafted on the surface are gathered at the bottom of the centrifuge tube, achieving effective separation from the liquid phase, and then washing; further, the washing treatment is to further remove residual impurities by washing the precipitate with anhydrous ethanol multiple times, and then by drying treatment, to ensure that the final modified Fe3O4 has a high purity, laying the foundation for subsequent participation in the construction of an efficient fire extinguishing agent system;

[0068] S4, dissolving PLGA in dichloromethane liquid to obtain a mixed liquid;

[0069] S5. Adding supercritical CO2 to the mixed liquid under supercritical conditions to form an oil-in-water emulsion;

[0070] S6. Under a supercritical state, the oil-in-water emulsion is stirred at a stirring rate of 1500 rpm, and the dichloromethane liquid is volatilized to obtain a CO2 phase change shell 14 in a monodisperse microcapsule state; wherein the stirred PLGA serves as the outer skin of the monodisperse microcapsule, and the supercritical CO2 is wrapped by the outer skin PLGA;

[0071] S7, dispersing the CO2 phase change shell 14 in a tetrahydrofuran solution containing poly N-vinyl carbazole, volatilizing the solvent after ultrasonic treatment, and forming a poly N-vinyl carbazole coating on the surface of the microcapsule; poly N-vinyl carbazole as a coating on the surface of the microcapsule has the property of shrinking when heated;

[0072] S8, dispersing the modified Fe3O4, charge enhancer 16 and surfactant 15 in the PDMS prepolymer at high speed for 20 minutes to obtain a transition product;

[0073] Among them, the modified Fe3O4 is grafted with the PDMS prepolymer due to the -SiO-C bond grafted on the surface. The charge enhancer 16 forms an electrostatic interaction or hydrogen bond through the silanized groups (such as residual polar groups) on the surface of the modified Fe3O4, adsorbs to the surface of the modified Fe3O4, and forms a charge layer. The repulsive force of the same charge prevents the particles from agglomerating, and promotes the uniform dispersion of Fe3O4 in the PDMS prepolymer. High-speed dispersion is a physical mixing technology that evenly disperses solid particles into a liquid medium through the shear force, impact force and centrifugal force generated by mechanical high-speed rotation, further achieving the purpose of uniformly distributing the modified Fe3O4 and the charge enhancer 16.

[0074] S9, adding a CO2 phase change shell 14 having a poly N-vinyl carbazole coating and TEOS to the transition product, and cross-linking in stages under the catalysis of dibutyltin dilaurate to form a fire extinguishing agent;

[0075] Among them, TEOS and PDMS form a three-dimensional network of colloids as a skeleton under catalysis, and the CO2 phase change shell 14 as a monomer will polymerize into the interior of the three-dimensional network of colloid skeleton to ensure the overall formation of the fire extinguishing agent, while the surfactant 15 can reduce surface tension and promote spreading, thereby improving the compatibility of the colloid with other components.

[0076] In some embodiments, the staged cross-linking includes a first stage and a second stage, wherein the first stage is a pre-polymerization treatment at a temperature of 50°C for 2 hours, and the second stage is a curing treatment at a temperature of 85°C for 12 hours; wherein the pre-polymerization treatment is a treatment method of pre-polymerizing monomers or oligomers to form a preliminary three-dimensional network structure, and the stability of the three-dimensional network and the stable connection of each monomer after pre-polymerization are ensured through curing treatment.

[0077] Example 3

[0078] Based on Example 2, Figure 2-Figure 5 The embodiment of the present invention provides a method for controlling a fire extinguishing agent in a microgravity environment, which specifically includes the following steps:

[0079] P1. When the fire detection module 24 detects a fire source, the driving module controls the storage module to release the fire extinguishing agent;

[0080] Among them, reference Figure 2As shown, the fire detection module 24 includes a thermal imager and a smoke sensor. The drive module includes several solenoid coils 22 evenly distributed on the inner wall of the spacecraft cabin 21, and an FPGA control submodule 23 that can be programmed and controls various electrical devices. The storage module includes a pressure vessel 25 for storing fire extinguishing agent and a nozzle 27 connected to the pressure vessel 25 via a discharge pipe. The discharge pipe is equipped with a solenoid valve 26. In addition, FPGA stands for Field Programmable Gate Array, and its Chinese name is field programmable logic gate array. It has higher integration, stronger logical functions, and greater flexibility, and has become one of the preferred devices for designing digital circuits or systems.

[0081] The fire source location is detected by both the thermal imager and the smoke detector, and the detected fire source location is transmitted to the FPGA control submodule 23 via an electrical signal. The FPGA control submodule 23 controls the corresponding solenoid valve 26 to open. Under the action of pressure, the fire extinguishing agent inside the pressure vessel 25 drives the fire extinguishing agent through the discharge pipe and solenoid valve 26 and is sprayed out from the nozzle 27 to achieve the purpose of releasing the fire extinguishing agent.

[0082] P2, the driving module generates a controllable gradient magnetic field, and the fire extinguishing agent moves toward the fire source;

[0083] Among them, reference Figure 3 As shown, the FPGA control submodule 23 controls the magnitude and direction of the current flowing into each solenoid electromagnetic coil 22 based on the position information in the fire alarm signal. According to the Biot-Savart law, when current flows in the coil, it generates a magnetic field in the space around it. The strength of the magnetic field is proportional to the current strength and inversely proportional to the distance. Therefore, by adjusting the current of each solenoid electromagnetic coil 22, a magnetic field gradient pointing to the fire source is generated.

[0084] For example, when the fire source is located inside an electronic cabinet in the equipment compartment, the solenoid coil current 22 near the fire source increases, thereby increasing the magnetic field strength in the area; the solenoid coil current 22 away from the fire source decreases accordingly, thereby forming a gradient of gradually increasing magnetic field strength from the surrounding area toward the fire source.

[0085] P3, the fire extinguishing agent reaches the fire source, releases supercritical CO2 and forms porous aerogel;

[0086] Among them, when the fire extinguishing agent contacts the surface of the fire source (temperature ≥ 200°C), the temperature of the modified Fe3O4 particles rises to the Curie point (580°C), the orderly arrangement of the magnetic domains is destroyed, the magnetization intensity drops sharply to below 10emu / g, the magnetic attraction inside the fire extinguishing agent disappears, it no longer moves, and the three-dimensional network structure relaxes. It should be added that the Curie point is the temperature at which the spontaneous magnetization intensity of a magnetic material drops to zero, and it is the critical point at which ferromagnetic or ferrimagnetic materials transform into paramagnetic materials;

[0087] In addition, high temperature causes the poly N-vinyl carbazole coating to shrink, and the stress of the PLGA outer skin of the CO2 phase change shell 14 is concentrated and ruptured, thereby releasing the supercritical CO2 inside the PLGA outer skin. The density of supercritical CO2 is 460kg / m 3 , between liquid and gas, supercritical CO2 absorbs heat through phase change, reducing the fire source temperature to below the ignition point at a rate of 25℃ / s, quickly suppressing the combustion chain reaction;

[0088] Furthermore, the siloxane matrix 11 undergoes a dehydration condensation reaction at a temperature ≥300°C, and the generated silica nanoparticles (particle size 5-10nm) self-assemble to form a porous aerogel with a porosity ≥90% and an average pore size of 20-50nm, achieving efficient scattering (scattering coefficient ≥100m 2 / kg), and the thermal conductivity of porous aerogel is as low as 0.012W / (m·K), which is superior to traditional aerospace thermal insulation materials (such as aerogel felt, with a thermal conductivity of 0.015W / (m·K)). It forms a thermal insulation barrier with a thickness of 50-150μm, blocking the contact of thermal radiation with oxygen, achieving the purpose of preventing re-ignition and improving fire extinguishing efficiency.

[0089] P4: After the fire is extinguished, the residue is recovered through the first recovery module and the second recovery module;

[0090] The first recycling module 3 includes a recycling electromagnetic coil 33, an outer cylinder 32 sleeved outside the recycling electromagnetic coil 33, and a first recycling bucket 31 accommodating the outer cylinder 32;

[0091] refer to Figure 4 As shown, the FPGA control submodule 23 supplies current to the spiral tube electromagnetic coil 22, and the magnetic residue after the fire is extinguished moves toward the recovery electromagnetic coil 33 and is adsorbed on the outer cylinder 32. Then, after the power supply to the recovery electromagnetic coil 33 is stopped, the magnetic residue is contained in the first recovery barrel 31, thereby realizing the recovery of the magnetic residue;

[0092] The second recovery module 4 includes a vacuum pump 43, the suction port of the vacuum pump 43 is connected to a plurality of suction heads 44 through a suction pipe, the air outlet of the vacuum pump 43 is connected to the second recovery bucket 41 through an air outlet pipe, and the second recovery bucket 41 is provided with a filter 42 near the end of the air outlet pipe;

[0093] refer to Figure 5 As shown, the airflow generated by the vacuum pump 43 causes the remaining non-magnetic residue to be sucked into the suction pipe from the suction head 44, and then enters the second recovery bucket 41 after passing through the vacuum pump 43 and the air outlet pipe. The non-magnetic residue will be blocked by the filter 42, ensuring the collection of the non-magnetic residue and the circulation of gas;

[0094] In summary, the first recovery module 3 and the second recovery module 4 separately recover the magnetic residue and the non-magnetic residue, which is convenient for subsequent secondary utilization or harmless treatment.

[0095] In this specification, the terms "connect," "install," and "fix" should be understood broadly. For example, "connect" can refer to a fixed connection, a detachable connection, or an integral connection; it can refer to a direct connection or an indirect connection through an intermediary. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0096] Throughout this specification, terms such as "one embodiment" or "some embodiments" mean that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0097] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A fire extinguishing agent for use in a microgravity environment, characterized in that: include: Magnetic core, content is 20-25 parts; CO2 phase change shell, content is 10-15 parts; Silicone matrix, content is 60-70 parts; Functional additives, content is 1-5 parts; The silicone matrix is ​​a three-dimensional network of elastic colloids, the magnetic core is uniformly dispersed in the three-dimensional network of elastic colloids, the CO2 phase change shell is uniformly dispersed in the three-dimensional network of elastic colloids in the form of microcapsules, and the interior of the microcapsules is supercritical CO2, and the functional additive includes a temperature-sensitive coating wrapped around the outside of the CO2 phase change shell.

2. The fire extinguishing agent according to claim 1, characterized in that The functional additive further comprises a charge enhancer and a surfactant uniformly dispersed in the three-dimensional network elastic colloid, wherein the content of the charge enhancer is 1-3 parts, the content of the surfactant is 0.1-0.5 parts, and the content of the temperature sensitive coating is 1-2 parts.

3. The fire extinguishing agent according to claim 1, characterized in that The magnetic core is Fe3O4 with a siloxane-philic -SiO-C bond grafted layer on the surface, the outer skin of the CO2 phase change shell is composed of PLGA, and the siloxane matrix is ​​PDMS and TEOS.

4. The method for preparing the fire extinguishing agent according to any one of claims 1 to 3, comprising the following steps: S1. Mixing Fe3O4 nanoparticles and KH-570 at a mass ratio of 1:0.2 and adding the mixture to anhydrous ethanol to obtain a mixed solution; S2, subjecting the mixed solution to ultrasonic dispersion treatment for 30 minutes, and then subjecting the mixture to reflux reaction for 2 hours to obtain a wet intermediate; S3, centrifuging, washing and drying the wet intermediate to obtain Fe3O4 with a siloxane-philic -SiO-C bond grafted layer on the surface, also known as modified Fe3O4; S4, dissolving PLGA in dichloromethane liquid to obtain a mixed liquid; S5. Adding supercritical CO2 to the mixed liquid under supercritical conditions to form an oil-in-water emulsion; S6. Under a supercritical state, the oil-in-water emulsion is stirred at a stirring rate of 1500 rpm, and the dichloromethane liquid is volatilized to obtain a CO2 phase change shell in a monodisperse microcapsule state; S7, dispersing the CO2 phase change shell in a tetrahydrofuran solution containing poly (N-vinyl carbazole), volatilizing the solvent after ultrasonic treatment, and forming a poly (N-vinyl carbazole) coating on the surface of the microcapsule; S8, dispersing the modified Fe3O4, charge enhancer and surfactant in the PDMS prepolymer at high speed for 20 minutes to obtain a transition product; S9. Adding a CO2 phase change shell having a poly N-vinyl carbazole coating and TEOS to the transition product, cross-linking in stages under the catalysis of dibutyltin dilaurate to form a fire extinguishing agent.

5. The method for preparing the fire extinguishing agent according to claim 4, characterized in that: The staged cross-linking includes a first stage and a second stage. The first stage is a prepolymerization treatment at a temperature of 50° C. for 2 hours, and the second stage is a curing treatment at a temperature of 85° C. for 12 hours.

6. The method for controlling a fire extinguishing agent according to any one of claims 1 to 3, comprising the following steps: P1. When the fire detection module detects a fire source, the drive module controls the storage module to release the fire extinguishing agent; P2, the driving module generates a controllable gradient magnetic field, and the fire extinguishing agent moves toward the fire source; P3, the fire extinguishing agent reaches the fire source, releases supercritical CO2 and forms porous aerogel; P4. After the fire is extinguished, the residues are recovered through the first recovery module and the second recovery module.

7. The method for controlling a fire extinguishing agent according to claim 6, characterized in that: In step P1, the driving module includes a plurality of solenoid coils evenly distributed on the inner wall of the spacecraft cabin, and an FPGA control submodule that can be programmed and control various electrical appliances.

8. The method for controlling a fire extinguishing agent according to claim 6, characterized in that: In step P1, the storage module includes a pressure vessel for storing the fire extinguishing agent, and a nozzle connected to the pressure vessel through a discharge pipe, and the discharge pipe is provided with a solenoid valve.

9. The method for controlling a fire extinguishing agent according to claim 6, characterized in that: In step P4, the first recovery module includes a recovery electromagnetic coil, an outer cylinder sleeved outside the recovery electromagnetic coil, and a first recovery bucket accommodating the outer cylinder; the second recovery module includes a vacuum pump, the suction port of the vacuum pump is connected to a plurality of suction heads through a suction pipe, the air outlet of the vacuum pump is connected to the second recovery bucket through an air outlet pipe, and the second recovery bucket is provided with a filter near the end of the air outlet pipe.

10. The method for controlling a fire extinguishing agent according to claim 6, characterized in that: The fire detection module includes a thermal imager and a smoke sensor.

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