Preparation method of ordered graphene / silicone rubber heat insulation layer for inhibiting migration of plasticizer

Abstract

The invention relates to a preparation method of an ordered graphene / silicone rubber heat insulation layer for inhibiting migration of a plasticizer. The preparation method comprises the following steps: preparing a magnetic nanoparticle-loaded graphene composite material; uniformly mixing the magnetic nanoparticle loaded graphene composite material with silicone rubber by a solvent method; the obtained graphene composite material loaded with the magnetic nanoparticles is orderly filled in a silicone rubber heat insulation layer under the induction of a rotating magnetic field; in the curing forming process, under the action of a rotating magnetic field, the composite material can move in a silicone rubber matrix and form an ordered structure, and then the ordered graphene / silicone rubber heat insulation layer is obtained. According to the method, the magnetic nanoparticle-loaded graphene composite material is uniformly dispersed in a silicon rubber matrix in a parallel and ordered manner to play a role of a physical barrier, so that the migration of an energy-containing small molecule plasticizer in a propellant to a heat insulation layer is effectively inhibited, and the stability, safety and reliability of a solid rocket engine are ensured.

Description

Technical Field

[0001] The present invention relates to a preparation method of an ordered graphene / silicone rubber thermal insulation layer for inhibiting plasticizer migration, and relates to the technical field of solid propellants. Background Art

[0002] Due to the advantages of simple structure, convenient operation and high energy density, solid rocket motors are widely used in the fields of missiles, satellites, spacecrafts and rocket launches. The thermal insulation layer is a key component to ensure the stable operation and safety of solid rocket motors. During the long-term storage of the engine charge, small molecule plasticizers will diffuse and migrate from the propellant grain into the thermal insulation layer, causing serious damage to the thermal insulation layer / propellant interface; on the other hand, moisture and water in the external environment will enter the engine charge through the surface of the thermal insulation layer and the thermal insulation layer / propellant interface, causing adverse effects such as swelling, plasticization and hydrolysis of the thermal insulation layer material, and reducing the interfacial adhesion strength with the propellant grain. In addition, a large amount of migration of plasticizers will also lead to a decrease in the ablation resistance of the thermal insulation layer, causing great damage to the overall solid engine. Therefore, how to avoid the aging of the charge interior and the interfacial debonding phenomenon caused by plasticizer migration during production and storage, and avoid potential safety hazards during the use of the engine are key issues that current researchers urgently need to solve. Graphene oxide (GO) has a unique two-dimensional layered structure and excellent gas and liquid barrier properties. Aiming at the migration problem of small molecule plasticizers, the barrier effect of GO can be used to play a role in inhibiting the migration of small molecule plasticizers. If graphene can be dispersed parallel and orderly into the thermal insulation layer and the advantages of its two-dimensional material can be fully utilized, the ability of the thermal insulation layer to inhibit the migration of small molecule components will be further enhanced, which is extremely beneficial to ensuring the stability and safety reliability of solid rocket motors. Summary of the Invention

[0003] The object of the present invention is to provide a preparation method of an ordered graphene / silicone rubber thermal insulation layer for inhibiting plasticizer migration. This thermal insulation layer can significantly inhibit the diffusion and migration of energetic plasticizers such as nitroglycerin from the propellant grain to the thermal insulation layer, and ensure the stability and safety reliability of solid rocket motors.

[0004] The technical solution for implementing the object of the present invention is as follows:

[0005] The present invention provides a preparation method of an ordered graphene / silicone rubber thermal insulation layer for inhibiting plasticizer migration, including:

[0006] Preparing a graphene composite material loaded with magnetic nanoparticles;

[0007] Preparing a dispersion of a graphene composite material loaded with magnetic nanoparticles;

[0008] Mix the dispersion of graphene composite material loaded with magnetic nanoparticles evenly with silicone rubber;

[0009] Pour the mixture into a mold and heat and cure it in a rotating parallel magnetic field. During the curing and forming process, under the action of the rotating parallel magnetic field, the graphene composite material loaded with magnetic nanoparticles will move in the silicone rubber matrix and form an ordered structure, thereby obtaining an ordered graphene / silicone rubber thermal insulation layer.

[0010] In an alternative embodiment, the graphene composite material loaded with magnetic nanoparticles includes one or more of Fe₃O₄ / graphene oxide, Fe₃O₄ / reduced graphene oxide, Co₃O₄ / graphene oxide, Co₃O₄ / reduced graphene oxide, Fe₂O₃ / graphene oxide, zinc ferrite / graphene oxide, and bismuth ferrite / graphene oxide composite materials.

[0011] In an alternative embodiment, when preparing the dispersion of the graphene composite material loaded with magnetic nanoparticles by ultrasonic dispersing the graphene composite material loaded with magnetic nanoparticles in an organic solvent, the ultrasonic power is 300 w - 800 w, and the ultrasonic time is 1 h - 2 h.

[0012] Specifically, the organic solvent is selected from one or more of toluene, cyclohexane, acetone, ethyl acetate, and N,N-dimethylformamide.

[0013] In an alternative embodiment, the concentration of the dispersion of the graphene composite material loaded with magnetic nanoparticles is 1 mg / mL - 10 mg / mL.

[0014] In an alternative embodiment, after pouring the mixture into a mold, heat and cure it in a rotating parallel magnetic field. The curing temperature is 60 - 100 °C, and the curing time is 60 min - 120 min.

[0015] In an alternative embodiment, a polytetrafluoroethylene mold, an aluminum alloy mold, or a copper alloy mold can be used during the curing and forming process.

[0016] In an alternative embodiment, under the action of the rotating magnetic field, the graphene composite material loaded with magnetic nanoparticles will move in the silicone rubber matrix and form an ordered structure, and the magnetic field intensity of the magnetic field is 0.1 T - 0.5 T.

[0017] In an alternative embodiment, pouring the mixture into a mold and heating and curing it in a rotating parallel magnetic field means placing the mold filled with the mixture on a sample stage, with a first magnet and a second magnet respectively arranged at both ends of the sample stage. The N pole of the first magnet is opposite to the S pole of the second magnet. By rotating the sample stage, during the rotation process, the direction remains unchanged, realizing the heating and curing process in a rotating parallel magnetic field.

[0018] In an alternative embodiment, the ordered graphene / silicone rubber thermal insulation layer comprises the following components: vinyl-terminated polydimethylsiloxane 100 wt%, graphene composite material loaded with magnetic nanoparticles 0.5 - 3 wt%, crosslinking agent hydrogen-containing silicone oil 3 wt%, and platinum catalyst 0.1 wt%.

[0019] The present invention has the following beneficial effects compared with the prior art:

[0020] (1) A graphene composite material loaded with magnetic nanoparticles was obtained by ultrasonic co-precipitation method. The action of ultrasonic waves can promote the uniform dispersion and size control of nanoparticles. This method has the advantages of simplicity, directness and flexibility, and is convenient for industrial production.

[0021] (2) The graphene composite material loaded with magnetic nanoparticles is orderly arranged in the silicone rubber thermal insulation layer under the action of a rotating magnetic field. The orderly orientation of magnetic nanoparticle fillers in the silicone rubber matrix serves as a dense physical barrier, and effectively inhibits the migration of energetic small molecule plasticizers in the propellant to the thermal insulation layer through the "tortuous path" effect, ensuring the stability, safety and reliability of solid rocket motors. Description of the Drawings

[0022] Figure 1 It is a schematic diagram of the preparation method of the ordered graphene / silicone rubber thermal insulation layer in the embodiment of the present invention.

[0023] Figure 2 It is a scanning electron microscope image of the graphene oxide loaded with magnetite obtained in Example 1 of the present invention.

[0024] Figure 3 It is a surface optical microscope photograph of the samples prepared in Example 1 of the present invention and Comparative Example 2.

[0025] Figure 4 It is a cross-sectional SEM image of the samples prepared in Example 1 of the present invention and Comparative Example 2.

[0026] Figure 5 It is a dynamic diagram of the orderly orientation of magnetic particles in the thermal insulation layer in Example 1 of the present invention, and a - f are optical microscope pictures of the samples at different times during the curing process.

[0027] Figure 6 It is a bar chart of the plasticizer concentration in the samples obtained in Examples 1 - 6 and Comparative Examples 1 - 2 of the present invention. Detailed Embodiments

[0028] In order to make the objectives, features and advantages of the present invention clearer and easier to understand, the following will explain in detail the specific implementation methods of the present invention in combination with embodiments.

[0029] In the following description, we will provide many specific details to facilitate a deep understanding of the present invention. However, the present invention can also be implemented in other ways different from those described herein, as long as the basic concept of the present invention is not violated, and those skilled in the relevant art can make similar expansions. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0030] Meanwhile, the "an embodiment" or "embodiments" referred to herein mean at least a certain feature, structure or property included in the implementation manner of the present invention. The appearances of "in an embodiment" in different parts of this document do not all refer to the same embodiment, and do not mean that these embodiments are independent of each other or mutually exclusive with other embodiments.

[0031] Please refer to Figure 1 , the present invention provides a method for preparing an ordered graphene / silicone rubber thermal insulation layer for suppressing plasticizer migration, including:

[0032] S1: Prepare a dispersion of graphene composite material loaded with magnetic nanoparticles;

[0033] S2: Mix the dispersion of graphene composite material loaded with magnetic nanoparticles with silicone rubber evenly;

[0034] S3: Pour the mixed solution into a mold and heat and cure it in a rotating parallel magnetic field: that is, place the mold filled with the mixed solution on a sample stage, and a first magnet and a second magnet are respectively arranged at both ends of the sample stage. The N pole of the first magnet is arranged opposite to the S pole of the second magnet. By rotating the sample stage, during the rotation process, the direction remains unchanged, and the heating and curing process in the rotating parallel magnetic field is realized; during the curing and forming process, under the action of the rotating parallel magnetic field, the graphene composite material loaded with magnetic nanoparticles will move in the silicone rubber matrix and form an ordered structure, and then an ordered graphene / silicone rubber thermal insulation layer is obtained.

[0035] Example 1

[0036] Step 1: Prepare iron oxide loaded graphene oxide by ultrasonic-assisted co-precipitation method. First, disperse 0.1 g of GO in 100 mL of deionized water and ultrasonicate for 0.5 h to obtain a suspension. Next, disperse 0.15 g of ferrous chloride tetrahydrate and 0.41 g of ferric chloride hexahydrate in 50 mL of deionized water, and then add them to the GO suspension. Then, add ammonium hydroxide dropwise to the suspension until the pH reaches 11. Then, react for 3 h under ultrasonic conditions with a power of 200 W and a frequency of 25 kHz to obtain iron oxide loaded graphene oxide. Finally, wash it with deionized water at least 3 times and freeze-dry it for later use; Figure 2 The SEM image of iron oxide loaded graphene oxide is shown, and it can be observed that iron oxide is dispersed on the graphene oxide sheets.

[0037] Step 2: Weigh 100 mg of iron oxide supported graphene oxide and place it in a beaker. Add 50 mL of acetone and disperse it by ultrasonic wave at a power of 500 w for 30 min to obtain an iron oxide supported graphene oxide / acetone dispersion with a concentration of 2 mg / ml;

[0038] Step 3: Weigh 10 g of vinyl polydimethylsiloxane in a flask and place it in a vacuum drying oven at 100 °C to remove water under vacuum for 3 h. Pour the dispersion into the flask and stir evenly, then use a rotary evaporator to remove the acetone solvent. Weigh 0.3 g of crosslinking agent and 10 mg of catalyst and add them to the flask, and stir well to make them evenly mixed;

[0039] Step 4: Pour the obtained mixed slurry into a polytetrafluoroethylene mold, and then place it on a sample stage. A first magnet and a second magnet are respectively arranged at both ends of the sample stage. The N pole of the first magnet is arranged opposite to the S pole of the second magnet. By rotating the sample stage, during the rotation process, the direction remains unchanged (always keep rotating counterclockwise or clockwise), the magnetic field strength is 0.2 T, the curing temperature is 100 °C, and the time is 60 min to obtain an ordered silicone rubber propellant insulation layer filled with iron oxide supported graphene oxide.

[0040] As Figure 3 shown, it can be observed under an optical microscope that iron oxide supported graphene oxide is orderly dispersed in the silicone rubber. Figure 4 Using SEM to observe the cross-section of the sample in Figure 5 can also observe that iron oxide supported graphene oxide is orderly dispersed in the silicone rubber. We also observed the dynamic orientation process of iron oxide supported graphene oxide during curing. As

[0041] shown, during the curing process, we used an optical microscope to observe. After applying the magnetic field, iron oxide supported graphene oxide moved rapidly. After about 30 seconds, an ordered structure became visible. After 120 seconds, it can be clearly observed that iron oxide supported graphene oxide has been orderly dispersed in the silicone rubber matrix.

[0041] Step 5: According to the regulations of QJ 916-1985 "Tensile Test Method for Adiabatic and Liner Materials in Solid Rocket Motor Combustion Chambers", prepare rectangular tensile specimens with an ordered silicone rubber propellant insulation layer filled with iron oxide supported graphene oxide; test the tensile strength under the conditions of a test temperature of 25 °C and a tensile speed of 100 mm / min. The test results are shown in Table 1.

[0042] Step 6: According to the regulations of WJ 2137-1993 "Determination of Nitroglycerin Migration Amount", use the liquid immersion method to test the concentration of the energetic plasticizer migrated to the insulation layer. Immerse the ordered silicone rubber propellant insulation layer filled with iron oxide supported graphene oxide in the energetic plasticizer and take it out regularly to weigh the mass until the material weight does not increase or the specimen is damaged. The test results are asFigure 6 as shown

[0043] Example 2

[0044] Step 1: Prepare reduced graphene oxide supported on magnetite by ultrasonic co-precipitation method. First, disperse 0.2 g of GO in 200 mL of deionized water and ultrasonicate for 1 h to obtain a suspension. Secondly, disperse 0.3 g of ferrous chloride tetrahydrate and 0.82 g of ferric chloride hexahydrate in 100 mL of deionized water, and then add it to the GO suspension. Next, add ammonia water dropwise to the suspension to adjust the pH to 11. Finally, after adding an appropriate amount of hydrazine hydrate, react for 3 h under ultrasonic conditions with a power of 200 W and a frequency of 25 kHz to obtain reduced graphene oxide supported on magnetite. Wash it with deionized water at least 3 times and freeze-dry for later use;

[0045] Step 2: Weigh 200 mg of reduced graphene oxide supported on magnetite and place it in a beaker, add 50 mL of toluene, and ultrasonically disperse it at a power of 200 w for 60 min to obtain a reduced graphene oxide supported on magnetite / toluene dispersion with a concentration of 4 mg / ml;

[0046] Step 3: Weigh 20 g of vinyl polydimethylsiloxane into a flask, place it in a vacuum drying oven at 100 °C to remove water under vacuum for 3 h. Pour the dispersion into the flask, stir evenly, and then use a rotary evaporator to remove the toluene solvent. Weigh 0.6 g of crosslinking agent and 20 mg of catalyst and add them to the flask, and stir well to make them mix evenly;

[0047] Step 4: Pour the obtained mixed slurry into an aluminum alloy mold and heat and cure it in a rotating parallel magnetic field. The magnetic field strength is 0.3 T, the curing temperature is 80 °C, and the time is 80 min to obtain an ordered silicone rubber propellant insulation layer filled with reduced graphene oxide supported on magnetite;

[0048] Step 5: According to the regulations of QJ 916-1985 "Tensile Test Method for Insulating and Lining Materials in Solid Rocket Motor Combustion Chambers", prepare rectangular tensile specimens with an ordered silicone rubber propellant insulation layer filled with reduced graphene oxide supported on magnetite; Test the tensile strength at a test temperature of 25 °C and a tensile speed of 100 mm / min. The test results are shown in Table 1.

[0049] Step 6: According to the regulations of WJ 2137-1993 "Determination of Nitroglycerin Migration Amount", use the liquid immersion method to test the concentration of the energetic plasticizer migrated to the insulation layer. Immerse the ordered silicone rubber propellant insulation layer filled with reduced graphene oxide supported on magnetite in the energetic plasticizer and take it out regularly to weigh the mass until the material weight does not increase or the specimen is damaged. The test results are as Figure 6 shown

[0050] Example 3

[0051] Step 1: Prepare cobalt cobalt oxide supported graphene oxide (Co3O4 / GO) by ultrasonic co-precipitation method. First, disperse 0.5 g of GO in 500 mL of deionized water and ultrasonicate for 1 h to obtain a suspension. Second, disperse 0.9 g of cobalt nitrate in 100 mL of deionized water, and then add it to the GO suspension. Next, add ammonia water dropwise to the suspension to adjust the pH to 10. React for 3 h under ultrasonic conditions with a power of 200 W and a frequency of 25 kHz. Put the above solution into an oven for drying treatment first. The dried solid is calcined at a high temperature under nitrogen protection and calcined at 400 °C for 3 hours to uniformly load cobalt cobalt oxide nanoparticles on the surface of GO. Finally, take it out after natural cooling to room temperature in the furnace to obtain Co3O4 / GO powder.

[0052] Step 2: Weigh 100 mg of Co3O4 / GO and place it in a beaker, add 50 mL of acetone, and ultrasonically disperse it at a power of 300 w for 60 min to obtain an acetone / Co3O4 / GO dispersion with a concentration of 2 mg / ml;

[0053] Step 3: Weigh 10 g of vinyl polydimethylsiloxane into a flask, place it in a vacuum drying oven at 100 °C for vacuum dehydration for 3 h. Pour the dispersion into the flask, stir evenly, and then use a rotary evaporator to remove the acetone solvent. Weigh 0.3 g of cross-linking agent and 10 mg of catalyst and add them to the flask, and stir well to make them mix evenly;

[0054] Step 4: Pour the obtained mixed slurry into a polytetrafluoroethylene mold and heat and cure it in a rotating parallel magnetic field. The magnetic field strength is 0.2 T, the curing temperature is 100 °C, and the time is 60 min to obtain an adiabatic layer of Co3O4 / GO modified ordered silicone rubber propellant;

[0055] Step 5: According to the regulations of QJ 916-1985 "Tensile Test Method for Adiabatic and Liner Materials in Solid Rocket Motor Combustion Chambers", prepare rectangular tensile specimens with an adiabatic layer of ordered silicone rubber propellant filled with Co3O4 / GO; test the tensile strength at a test temperature of 25 °C and a tensile speed of 100 mm / min. The test results are shown in Table 1.

[0056] Step 6: According to the regulations of WJ 2137-1993 "Determination of Nitroglycerin Migration Amount", use the liquid immersion method to test the concentration of the energetic plasticizer migrated to the adiabatic layer. Immerse the adiabatic layer of ordered silicone rubber propellant filled with Co3O4 / GO in the energetic plasticizer and take it out regularly to weigh the mass until the material weight does not increase or the specimen is damaged. The test results are as Figure 6 shown.

[0057] Example 4

[0058] Step 1: Prepare cobalt ferrite supported reduced graphene oxide (Co3O4 / RGO) by ultrasonic co-precipitation method. First, disperse 0.5 g of GO in 500 mL of deionized water and ultrasonicate for 1 h to obtain a suspension. Second, disperse 0.9 g of cobalt nitrate in 100 mL of deionized water and then add it to the GO suspension. Next, add ammonia water dropwise to the suspension to adjust the pH to 10. After adding an appropriate amount of hydrazine hydrate, react the above solution under ultrasonic conditions with a power of 200 W and a frequency of 25 kHz for 3 h, wash, and dry. Calcinate the dried solid under nitrogen protection at 400 °C for 3 hours to uniformly load cobalt ferrite nanoparticles on the surface of RGO. Finally, take it out after natural cooling to room temperature in the furnace to obtain Co3O4 / RGO powder.

[0059] Step 2: Weigh 300 mg of Co3O4 / RGO and place it in a beaker, add 100 mL of cyclohexane, and ultrasonically disperse it at a power of 600 w for 60 min to obtain an acetone / Co3O4 / GO dispersion with a concentration of 3 mg / ml;

[0060] Step 3: Weigh 15 g of vinyl polydimethylsiloxane into a flask and place it in a vacuum drying oven at 100 °C to remove water under vacuum for 3 h. Pour the dispersion into the flask, stir evenly, and then use a rotary evaporator to remove the cyclohexane solvent. Weigh 0.45 g of cross-linking agent and 15 mg of catalyst and add them to the flask, and stir well to make them mix evenly;

[0061] Step 4: Pour the obtained mixed slurry into a polytetrafluoroethylene mold and heat and cure it in a rotating parallel magnetic field with a magnetic field strength of 0.5 T, a curing temperature of 80 °C, and a time of 100 min to obtain an adiabatic layer of Co3O4 / RGO modified ordered silicone rubber propellant;

[0062] Step 5: According to the regulations of QJ 916-1985 "Tensile Test Method for Adiabatic and Liner Materials in Solid Rocket Motor Combustion Chambers", prepare rectangular tensile specimens with an adiabatic layer of ordered silicone rubber propellant filled with Co3O4 / RGO; test the tensile strength at a test temperature of 25 °C and a tensile speed of 100 mm / min. The test results are shown in Table 1.

[0063] Step 6: According to the regulations of WJ 2137-1993 "Determination of Nitroglycerin Migration Amount", use the liquid immersion method to test the concentration of the energetic plasticizer migrated to the adiabatic layer. Immerse the adiabatic layer of ordered silicone rubber propellant filled with Co3O4 / RGO in the energetic plasticizer and take it out regularly to weigh the mass until the material weight does not increase or the specimen is damaged. The test results are as Figure 6 shown.

[0064] Example 5

[0065] Step 1: Prepare zinc ferrite loaded graphene oxide (ZF / GO) by ultrasonic co-precipitation method. First, disperse 0.5 g of GO in 500 mL of deionized water and ultrasonicate for 1 h to obtain a suspension. Second, disperse 0.15 g of zinc nitrate and 0.41 g of zinc nitrate in 50 mL of deionized water, and then add it to the GO suspension. Next, add ammonia water dropwise to the suspension to adjust the pH to 10. React the above solution under ultrasonic conditions with a power of 200 W and a frequency of 25 kHz for 3 h, then wash and dry. Calcinate the dried solid under nitrogen protection at 400 °C for 3 hours to uniformly load zinc ferrite nanoparticles on the surface of GO. Finally, take it out after natural cooling to room temperature in the furnace to obtain ZF / GO powder.

[0066] Step 2: Weigh 400 mg of ZF / GO and place it in a beaker, add 200 mL of cyclohexane, and ultrasonically disperse it at a power of 800 w for 30 min to obtain a cyclohexane / ZF / GO dispersion with a concentration of 2 mg / ml;

[0067] Step 3: Weigh 40 g of vinyl polydimethylsiloxane in a flask and place it in a vacuum drying oven at 100 °C to remove water under vacuum for 3 h. Pour the dispersion into the flask, stir evenly, and then use a rotary evaporator to remove the cyclohexane solvent. Weigh 0.6 g of cross-linking agent and 40 mg of catalyst and add them to the flask, and stir well to make them evenly mixed;

[0068] Step 4: Pour the obtained mixed slurry into a polytetrafluoroethylene mold and heat and cure it in a rotating parallel magnetic field with a magnetic field strength of 0.6 T, a curing temperature of 90 °C, and a time of 70 min to obtain an adiabatic layer of ZF / GO modified ordered silicone rubber propellant;

[0069] Step 5: According to the regulations of QJ 916-1985 "Tensile Test Method for Adiabatic and Liner Materials in Solid Rocket Motor Combustion Chambers", prepare rectangular tensile specimens with an adiabatic layer of ordered silicone rubber propellant filled with ZF / GO; test the tensile strength at a test temperature of 25 °C and a tensile speed of 100 mm / min, and the test results are shown in Table 1.

[0070] Step 6: According to the regulations of WJ 2137-1993 "Determination of Nitroglycerin Migration Amount", use the liquid immersion method to test the concentration of the energetic plasticizer migrated to the adiabatic layer. Immerse the adiabatic layer of ordered silicone rubber propellant filled with ZF / GO in the energetic plasticizer and take it out regularly to weigh the mass until the material weight does not increase or the specimen is damaged. The test results are as Figure 6 shown.

[0071] Example 6

[0072] Step 1: Prepare bismuth ferrite supported reduced graphene oxide (BiFeO3 / RGO) by ultrasonic co-precipitation method. First, disperse 0.5 g of GO in 500 mL of deionized water and ultrasonicate for 1 h to obtain a suspension. Second, disperse 0.15 g of bismuth nitrate and 0.41 g of iron nitrate in 50 mL of deionized water, and then add it to the GO suspension. Next, add ammonia water dropwise to the suspension to adjust the pH to 10. After adding an appropriate amount of hydrazine hydrate, react the above solution under ultrasonic conditions with a power of 200 W and a frequency of 25 kHz for 3 h, wash, and dry. Calcinate the dried solid under nitrogen protection at 500 °C for 3 hours to uniformly load BiFeO3 nanoparticles on the surface of RGO. Finally, take it out after natural cooling to room temperature in the furnace to obtain BiFeO3 / RGO powder.

[0073] Step 2: Weigh 100 mg of Co3O4 / RGO and place it in a beaker, add 50 mL of acetone, and ultrasonically disperse it at a power of 300 w for 60 min to obtain an acetone / BiFeO3 / RGO dispersion with a concentration of 2 mg / ml;

[0074] Step 3: Weigh 10 g of vinyl polydimethylsiloxane in a flask, place it in a vacuum drying oven at 100 °C to remove water under vacuum for 3 h. Pour the dispersion into the flask, stir evenly, and then use a rotary evaporator to remove the cyclohexane solvent. Weigh 0.3 g of cross-linking agent and 10 mg of catalyst and add them to the flask respectively, and stir well to make them mix evenly;

[0075] Step 4: Pour the obtained mixed slurry into a polytetrafluoroethylene mold and heat and cure it in a rotating parallel magnetic field with a magnetic field strength of 0.3 T, a curing temperature of 70 °C, and a time of 100 min to obtain an adiabatic layer of BiFeO3 / RGO modified ordered silicone rubber propellant;

[0076] Step 5: According to the regulations of QJ 916-1985 "Tensile Test Method for Adiabatic and Liner Materials in Solid Rocket Motor Combustion Chambers", prepare rectangular tensile specimens with an adiabatic layer of ordered silicone rubber propellant filled with BiFeO3 / RGO; test the tensile strength at a test temperature of 25 °C and a tensile speed of 100 mm / min, and the test results are shown in Table 1.

[0077] Step 6: According to the regulations of WJ 2137-1993 "Determination of Nitroglycerin Migration Amount", use the liquid immersion method to test the concentration of the energetic plasticizer migrated to the adiabatic layer. Immerse the adiabatic layer of ordered silicone rubber propellant filled with BiFeO3 / RGO in the energetic plasticizer and take it out regularly to weigh the mass until the material weight no longer increases or the specimen is damaged. The test results are as Figure 6 shown.

[0078] Comparative Example 1

[0079] Step 1: Weigh 100 mg of graphene oxide and place it in a beaker. Add 50 mL of acetone and ultrasonically disperse it for 30 min at a power of 500 w to obtain a graphene oxide / acetone dispersion with a concentration of 2 mg / ml.

[0080] Step 2: Weigh 10 g of vinyl polydimethylsiloxane into a flask and place it in a vacuum drying oven at 100 °C to remove water under vacuum for 3 h. Pour the dispersion into the flask, stir evenly, and then use a rotary evaporator to remove the acetone solvent. Weigh 0.3 g of crosslinking agent and 10 mg of catalyst and add them to the flask, and stir well to make them evenly mixed.

[0081] Step 3: Pour the obtained mixed slurry into a polytetrafluoroethylene mold for curing at a curing temperature of 100 °C for 60 min to obtain a silicone rubber propellant insulation layer filled with graphene oxide.

[0082] Step 4: According to the regulations of QJ 916-1985 "Tensile Test Method for Adiabatic and Liner Materials in Solid Rocket Motor Combustion Chambers", prepare rectangular tensile specimens with the silicone rubber propellant insulation layer filled with graphene oxide. Test the tensile strength at a test temperature of 25 °C and a tensile speed of 100 mm / min. The test results are shown in Table 1.

[0083] Step 5: According to the regulations of WJ 2137-1993 "Determination of Nitroglycerin Migration Amount", use the liquid immersion method to test the concentration of the energetic plasticizer migrated to the insulation layer. Immerse the silicone rubber propellant insulation layer filled with graphene oxide in the energetic plasticizer and take it out regularly to weigh the mass until the material weight does not increase or the specimen is damaged. The test results are as Figure 6 shown.

[0084] Comparative Example 2

[0085] Step 1: Prepare iron oxide (III) - loaded reduced graphene oxide by ultrasonic co - precipitation method. First, disperse 0.2 g of GO in 200 mL of deionized water and ultrasonically treat it for 1 h to obtain a suspension. Secondly, disperse 0.3 g of ferrous chloride tetrahydrate and 0.82 g of ferric chloride hexahydrate in 100 mL of deionized water, and then add it to the GO suspension. Next, add ammonia water dropwise to the suspension to adjust the pH to 11. Finally, after adding an appropriate amount of hydrazine hydrate, react for 3 h under ultrasonic conditions with a power of 200 W and a frequency of 25 kHz to obtain iron oxide (III) - loaded reduced graphene oxide. Wash it with deionized water at least 3 times and freeze - dry it for later use.

[0086] Step 2: Weigh 200 mg of iron oxide (III) - loaded reduced graphene oxide and place it in a beaker. Add 50 mL of toluene and ultrasonically disperse it for 60 min at a power of 200 w to obtain an iron oxide (III) - loaded reduced graphene oxide / toluene dispersion with a concentration of 4 mg / ml.

[0087] Step 3: Weigh 20 g of vinyl polydimethylsiloxane into a flask, and place it in a vacuum drying oven at 100 °C to remove water under vacuum for 3 h. Pour the dispersion into the flask, stir evenly, and then use a rotary evaporator to remove the toluene solvent. Weigh 0.6 g of crosslinking agent and 20 mg of catalyst respectively and add them to the flask, and stir well to make them evenly mixed;

[0088] Step 4: Pour the obtained mixed slurry into an aluminum alloy mold for curing. The curing temperature is 80 °C and the time is 80 min to obtain an ordered silicone rubber propellant insulation layer filled with Fe₃O₄-loaded reduced graphene oxide (SR / Fe₃O₄ / RGO); as Figure 3 shown, a large amount of aggregation of Fe₃O₄-loaded reduced graphene oxide in silicone rubber can be observed under an optical microscope. Figure 4 Using SEM to observe the cross-section of the sample can also show that the dispersion of Fe₃O₄-loaded graphene oxide in silicone rubber is uneven.

[0089] Step 5: According to the regulations of QJ 916-1985 "Tensile Test Method for Adiabatic and Liner Materials in Solid Rocket Motor Combustion Chambers", use the ordered silicone rubber propellant insulation layer filled with Fe₃O₄-loaded reduced graphene oxide to prepare rectangular tensile specimens; test the tensile strength at a test temperature of 25 °C and a tensile speed of 100 mm / min. The test results are shown in Table 1.

[0090] Step 6: According to the regulations of WJ 2137-1993 "Determination of Nitroglycerin Migration Amount", use the liquid immersion method to test the concentration of the energetic plasticizer migrated to the insulation layer. Immerse the ordered silicone rubber propellant insulation layer filled with Fe₃O₄-loaded reduced graphene oxide in the energetic plasticizer and take it out regularly to weigh the mass until the material weight no longer increases or the specimen is damaged. The test results are as Figure 6 shown.

[0091] Table 1 Data table of the tensile properties of the samples

[0092]

[0093]

Claims

1. A preparation method of an ordered graphene / silicone rubber thermal insulation layer for inhibiting plasticizer migration, characterized in that, Including: Preparing a magnetic nanoparticle-loaded graphene composite material; Preparing a dispersion of a magnetic nanoparticle-loaded graphene composite material; Mixing the dispersion of the magnetic nanoparticle-loaded graphene composite material with silicone rubber evenly; Pouring the mixture into a mold and heating and curing it in a rotating parallel magnetic field. During the curing and forming process, under the action of the rotating parallel magnetic field, the magnetic nanoparticle-loaded graphene composite material will move in the silicone rubber matrix and form an ordered structure, obtaining an ordered graphene / silicone rubber thermal insulation layer.

2. The method according to claim 1, wherein The magnetic nanoparticle-loaded graphene composite material includes one or more of Fe₃O₄ / graphene oxide, Fe₃O₄ / reduced graphene oxide, Co₃O₄ / graphene oxide, Co₃O₄ / reduced graphene oxide, Fe₂O₃ / graphene oxide, ZnFe₂O₄ / graphene oxide, and BiFeO₃ / graphene oxide composite materials.

3. The method according to claim 1, characterized in that, When preparing the dispersion of the magnetic nanoparticle-loaded graphene composite material by ultrasonic dispersing the magnetic nanoparticle-loaded graphene composite material in an organic solvent, the ultrasonic power is 300 w - 800 w, and the ultrasonic time is 1 h - 2 h.

4. The method according to claim 1, characterized in that The concentration of the dispersion of the magnetic nanoparticle-loaded graphene composite material is 1 mg / mL - 10 mg / mL.

5. The method according to claim 1, wherein Pouring the mixture into a mold and heating and curing it in a rotating parallel magnetic field, the curing temperature is 60 - 100 °C, and the curing time is 60 min - 120 min.

6. The method according to claim 1, wherein Under the action of the rotating magnetic field, the magnetic nanoparticle-loaded graphene composite material will move in the silicone rubber matrix and form an ordered structure, and the magnetic field intensity of the magnetic field is 0.1 T - 0.5 T.

7. The method according to claim 1, characterized in that, Pouring the mixture into a mold and heating and curing it in a rotating parallel magnetic field means placing the mold filled with the mixture on a sample stage, with a first magnet and a second magnet respectively arranged at both ends of the sample stage, the N pole of the first magnet is opposite to the S pole of the second magnet, and by rotating the sample stage, during the rotation process, the direction remains unchanged, realizing the heating and curing process in a rotating parallel magnetic field.

8. The method according to claim 1, wherein The described ordered graphene / silicone rubber thermal insulation layer includes the following components: vinyl-terminated polydimethylsiloxane 100 wt%, magnetic nanoparticle-loaded graphene composite material 0.5 - 3 wt%, crosslinking agent hydrogen-containing silicone oil 3 wt%, and platinum catalyst 0.1 wt%.

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