Graphene-based aerogel organic coating as well as preparation method and application thereof

Abstract

The invention discloses a graphene-based aerogel organic coating as well as a preparation method and application thereof, and relates to the technical field of coating preparation. The coating is formed by mixing polyaniline-reduced graphene oxide composite aerogel RGP filler and a high-temperature-resistant polyurethane matrix and has excellent high-temperature resistance and corrosion resistance, and a coating can be kept for 30 min at the temperature of 200 DEG C to be complete and free of discoloration and blistering and falling phenomena; the corrosion resistance time in a 3.5 wt% sodium chloride solution can reach 360-672 h, and the electrochemical impedance range is 8.8 * 10 <-9 >-1.8 * 10 <-8 > omega.cm <-2 >.

Description

Technical Field

[0001] The present invention relates to the technical field of coating preparation, and specifically to a graphene-based aerogel organic coating and its preparation method and application. Background Art

[0002] The thermal pipe system of ocean-going ships is in a harsh environment of high temperature, high salt and high humidity for a long time. Traditional coatings are prone to decomposition and carbonization at high temperatures and have insufficient corrosion resistance in strong corrosive media, resulting in rapid failure of the coating, seriously affecting the stability and life of the equipment, and may cause high economic losses or even system paralysis. Therefore, it is urgent to develop high-performance high-temperature resistant and anti-corrosion organic coatings.

[0003] In recent years, graphene-based materials have achieved remarkable results in the field of coatings, especially having great potential in high-temperature resistant and anti-corrosion coatings. Graphene-based aerogel, as a new type of nanomaterial, is formed by curling and stacking two-dimensional graphene nanosheets to form a unique three-dimensional structure, with ultra-low density, high specific surface area and porosity, high thermal conductivity and excellent mechanical properties. The difference in thermal conductivity between its horizontal and vertical directions and the complex pore structure are expected to significantly improve the high-temperature resistance and anti-corrosion performance of the coating.

[0004] However, there are problems such as poor dispersibility and poor compatibility with the base material in the application of graphene-based aerogel in coatings. Polyaniline has good compatibility with resin base materials due to the presence of polar groups and conjugated π bonds in its molecular structure. The conjugated system enhances the thermal stability, and the hydrogen bonds between molecular chains form a close-packed structure, further improving the thermal stability. In addition, the unique redox characteristics and passivation film effect of polyaniline can effectively inhibit corrosion. Combining polyaniline with graphene-based aerogel can improve the problems of dispersibility and compatibility of graphene aerogel, and is expected to further improve the temperature resistance and anti-corrosion performance of the material. Although organic resins have excellent film-forming properties, flexibility and adhesion, their sensitivity to high temperatures limits their application. Therefore, the development of a graphene-based aerogel organic coating doped with polyaniline provides a new way for the preparation of coatings with both high-temperature resistance and anti-corrosion performance, and is expected to meet the high requirements of modern industry for coatings. Summary of the Invention

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention provides a preparation method of a graphene-based aerogel organic coating, comprising the following steps:

[0007] Step 1, Preparation of reduced graphene oxide aerogel: Mix hydroxylated graphene oxide, deionized water, oxidant hydrazine hydrate, and ammonia water with a concentration of 25% - 28% in a hydrothermal reaction kettle under constant temperature and pressure, maintain at 95°C for 120 min for the redox process. After the reaction, filter and wash, refrigerate at -80°C for 4 h, and then place in a freeze dryer at -60°C for 24 h to obtain reduced graphene oxide aerogel. Specifically:

[0008] Step 1.1, Measure 0.9 parts by mass of hydroxylated graphene oxide and 0.3 parts by mass of deionized water, prepare a graphene oxide gel solution with a concentration of 3 mg / mL, place it in an ultrasonic dispersion instrument and ultrasonicate for 20 min. During the ultrasonication process, control the temperature of the water tank through circulating ice water not to exceed 15°C to obtain a homogeneous solution;

[0009] Step 1.2, Place the homogeneous solution above a magnetic stirrer, keep the rotation speed at 300 rpm, use a pipette to gradually add 0.018 parts by mass of ammonia water with a concentration of 25% - 28% dropwise to the homogeneous solution and stir for 5 min. The ammonia water provides an alkaline environment for the reaction to promote the redox reaction. After mixing, measure 0.005 parts by mass of oxidant hydrazine hydrate and add it dropwise, and continue ultrasonication for 15 min to obtain a hydrogel-like mixture;

[0010] Step 1.3, Add the hydrogel-like mixture to a hydrothermal reaction kettle under constant temperature and pressure, seal it, set the maintenance temperature at 95°C, the maintenance time at 120 min, and the heating time at 20 min;

[0011] Step 1.4, Filter the reacted mixed reagent with a 3M filter membrane, then filter with a 0.45 μm filter membrane, wash three times with deionized water to remove the residual ammonia water, and further wash with an alcohol solution and replace the aqueous solution to shorten the freeze-drying time;

[0012] Step 1.5, Put the filtered and washed solid part into a round reagent kit, freeze at -20°C for 2 h, then transfer to -80°C and freeze for 4 h to be completely shaped. Subsequently, place the freeze-dried sample in a freeze dryer and freeze at -60°C for 24 h to obtain the reduced graphene oxide aerogel to be measured;

[0013] Step 1.6, Measure the thermal conductivity λ in the horizontal direction of the reduced graphene oxide aerogel to be measured with a thermal conductivity meter h1 and the thermal conductivity λ in the vertical direction v1 , when λ h1 / λ v1 <10, then return to Step 1.2, increase the proportion of hydrazine hydrate by a gradient of 0.002 parts by mass to 0.007 parts by mass, cycle Steps 1.2 to 1.5. If still measured λ h1 / λ v1<10, then return to Step 1.2 again, continue to increase the proportion of hydrazine hydrate in a gradient of 0.002 parts by mass, and the parts by mass of hydrazine hydrate do not exceed 0.01, and cycle Steps 1.2 to 1.5 until λ h1 / λ v1 >10, end the cycle to obtain reduced graphene oxide aerogel;

[0014] Step 2, Preparation of aniline sol: Mix 2.796 parts by mass of aniline monomer with 1.825 parts by mass of 1 mol / L hydrochloric acid solution, and ultrasonically treat for 30 min at 0 - 4 °C to obtain aniline sol, and maintain a continuous ice bath environment;

[0015] Step 3, Weigh 0.05 parts by mass of reduced graphene oxide aerogel and 1 part by mass of aniline, and fully dissolve them in 1.825 parts by mass of 1 mol / L hydrochloric acid solution, ultrasonically mix for 10 min evenly, and add the obtained mixed solution to the aniline sol prepared in Step 2 for reaction, and stir at a rotation speed of 300 rpm for 30 min in an ice bath environment to obtain an aniline-reduced graphene oxide aerogel hybrid system, where the reduced graphene oxide aerogel serves as the carrier skeleton;

[0016] Step 4, Sol-gelation: Dissolve 6.846 parts by mass of oxidant ammonium persulfate in 3.65 parts by mass of 1 mol / L hydrochloric acid solution, stir at a rotation speed of 300 rpm for 10 min, and add it to the aniline-reduced graphene oxide aerogel hybrid system for gelation and polymerization reaction, and stir at a rotation speed of 300 rpm for 7 h in an environment of 0 - 4 °C;

[0017] Step 5, Filter the reaction product in Step 4 with a 3M filter membrane and a 0.45 μm filter membrane, wash it three times with distilled water, then perform displacement washing with an alcohol solution, refrigerate at -80 °C for 4 h, and then place it in a freeze-drying oven at -60 °C for freeze-drying for 36 h to obtain the to-be-tested polyaniline-reduced graphene oxide composite aerogel;

[0018] Step 6, Measure the thermal conductivity λ h2 in the horizontal direction and the thermal conductivity λ v2 in the vertical direction of the to-be-tested polyaniline-reduced graphene oxide composite aerogel. When λ h2 / λ v2 <6, then return to Step 3, increase the proportion of reduced graphene oxide aerogel in a gradient of 0.01 parts by mass to 0.06 parts by mass, cycle Steps 3 to 5. If it is still measured that λ h2 / λ v2 <6, then return to Step 3 again, increase the proportion of reduced graphene oxide aerogel in a gradient of 0.01 parts by mass, and the parts by mass of reduced graphene oxide aerogel do not exceed 0.5, and cycle Steps 3 to 5. If it is measured that λh2 / λ v2 >6, then perform a thermogravimetric analysis test under a nitrogen atmosphere. While maintaining a heating rate of 10 °C / min, when heating from room temperature to 400 °C, if the mass loss rate W satisfies W > 12%, then return to step 3 again. Increase the proportion of reduced graphene oxide aerogel in gradients of 0.01 part by mass and cycle through steps 3 to 5 until h2 / λ v2 >6 and W < 12%, end the cycle to obtain a polyaniline-reduced graphene oxide composite aerogel;

[0019] Step 7, synthesis of a high-temperature resistant polyurethane matrix coating containing fillers. Based on the method of mixing 5 - 30 parts by mass of a chain extender MOCA, 100 parts by mass of a polyurethane prepolymer, and 100 parts by mass of ethyl acetate and performing ultrasonic polycondensation to obtain the high-temperature resistant polyurethane matrix coating, specifically:

[0020] Weigh 5 - 30 parts by mass of MOCA, seal it, and heat it on a heating table at 120 °C until it melts. Weigh 100 parts by mass of the polyurethane prepolymer, seal it, and heat it on a heating table at 70 °C until it melts. Use the polyaniline-reduced graphene oxide composite aerogel as a filler. Dissolve 1 - 3 parts by mass of the polyaniline-reduced graphene oxide composite aerogel in 100 parts by mass of an ethyl acetate solution, ultrasonically mix it for 15 min, add the mixed reagent to the melted polyurethane prepolymer and ultrasonically mix it again for 15 min. Finally, add the melted MOCA to the mixed reagent and stir until it is evenly mixed to obtain a high-temperature resistant polyurethane matrix coating containing fillers, that is, obtain a graphene-based aerogel high-temperature resistant and corrosion-resistant organic coating.

[0021] Preferably, the said step 2 includes:

[0022] Step 2.1, weigh 18 mL of hydrochloric acid solution into a beaker, stir it with a glass rod and slowly add 150 mL of distilled water. Place the mixed solution in a 200 mL volumetric flask, and after cooling, add distilled water to make up the volume to 200 mL and shake well to obtain 200 mL of 1 mol / L hydrochloric acid solution;

[0023] Step 2.2, weigh 2.796 parts by mass of aniline monomer and add it to 1.825 parts by mass of the 1 mol / L hydrochloric acid solution. Keep the mixed solution in the range of 0 - 4 °C and perform ultrasonic treatment for 10 min. After it is dissolved evenly, transfer it to an ice bath environment and stir at a rotation speed of 300 rpm for 20 min, keeping the temperature below 4 °C to obtain an aniline sol, and maintain a continuous ice bath environment.

[0024] The present invention also provides a graphene-based aerogel organic coating, which is prepared by the preparation method of the graphene-based aerogel organic coating as described above.

[0025] The present invention also provides an application of the graphene-based aerogel organic coating as described above as a surface coating for any one of Q235 steel, aluminum alloy, and copper alloy.

[0026] The present invention has the following beneficial effects:

[0027] Applying the graphene-based aerogel (polyaniline-reduced graphene oxide composite aerogel) material to the organic coating provides a new idea for the development of high-temperature resistant and corrosion-resistant coatings.

[0028] Fully combining the structural characteristics and heat transfer and corrosion resistance advantages of the reduced graphene oxide aerogel and the polyaniline aerogel, a more dense composite aerogel with a complex corrosion medium propagation path is constructed.

[0029] Using the reduced graphene oxide aerogel as the skeleton support material, its rich surface area provides sufficient loading sites for the polyaniline aerogel, enhancing the mechanical properties of the material. Conversely, the attachment of the polyaniline aerogel successfully solves the problems of poor dispersibility and poor compatibility with the base material of the reduced graphene oxide aerogel.

[0030] This coating first raises the temperature resistance range of the polyurethane-based coating to 200 °C and can maintain it for at least 30 minutes. Moreover, environmentally friendly materials are used in the preparation process of this coating, reducing environmental pollution. Brief Description of the Drawings

[0031] Figure 1 is the preparation and application flow chart of the graphene-based aerogel high-temperature resistant and corrosion-resistant organic coating of the present invention;

[0032] Figure 2 is the SEM image of graphene oxide;

[0033] Figure 3 is the SEM image of the reduced graphene oxide aerogel;

[0034] Figure 4 is the SEM image of the polyaniline-reduced graphene oxide composite aerogel;

[0035] Figure 5 For the corresponding Figure 4 is the energy spectrum diagram of the polyaniline-reduced graphene oxide composite aerogel in

[0036] Figure 6 is the Fourier infrared spectrum diagram of graphene oxide, reduced graphene oxide aerogel, and polyaniline-reduced graphene oxide composite aerogel;

[0037] Figure 7 is the XRD diagram of graphene oxide, reduced graphene oxide aerogel, and polyaniline-reduced graphene oxide composite aerogel;

[0038] Figure 8 It is a physical picture of polyaniline-reduced graphene oxide composite aerogel;

[0039] Figure 9 It is a graph of the temperature resistance test and the temperature resistance limit test of polyurethane coatings with different hard and soft segment ratios;

[0040] Figure 10 It is a salt spray experiment test graph of high-temperature resistant and corrosion-resistant organic coatings of graphene-based aerogels with different RGP contents;

[0041] Figure 11 It is a polarization curve graph of high-temperature resistant and corrosion-resistant organic coatings of graphene-based aerogels with different RGP contents;

[0042] Figure 12 It is an electrochemical impedance graph of high-temperature resistant and corrosion-resistant organic coatings of graphene-based aerogels with different RGP contents;

[0043] Figure 13 It is a surface morphology graph of coatings with different contents of polyaniline-reduced graphene oxide composite aerogel maintained in a drying environment at 200 °C for 30 min and subjected to 15 cycles of hot and cold alternation in a room temperature environment. Specific implementation manners

[0044] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0045] The present invention will be further described in detail below according to the drawings and embodiments.

[0046] Embodiment 1

[0047] The embodiment of the present application provides a preparation method of a graphene-based aerogel organic coating. The preparation process is referred to Figure 1 , and includes the following steps:

[0048] Step 1, preparation of reduced graphene oxide aerogel. Hydroxylated graphene oxide, deionized water, oxidant hydrazine hydrate, and ammonia water with a concentration of 25% - 28% are mixed and then maintained at 95 °C for 120 min in a constant temperature and constant pressure hydrothermal reaction kettle for the redox process. After the reaction, filtration and washing are carried out, refrigerated at -80 °C for 4 h, and then placed in a freeze-drying oven at -60 °C for 24 h to obtain reduced graphene oxide aerogel, which specifically includes the following steps:

[0049] Step 1.1, Measure 0.9 parts by mass of hydroxylated graphene oxide and 0.3 parts by mass of deionized water, prepare a graphene oxide gel solution with a concentration of 3 mg / mL, place it in an ultrasonic dispersion instrument and ultrasonicate for 20 min. During the ultrasonication process, control the temperature of the water tank with circulating ice water not to exceed 15 °C to obtain a homogeneous solution after sufficient dispersion;

[0050] Step 1.2, Place the homogeneous solution above a magnetic stirrer, keep the rotation speed at 300 rpm, use a pipette to slowly add 0.018 parts by mass of ammonia water with a concentration of 25% - 28% dropwise into the homogeneous solution and stir for 5 min. The ammonia water provides an alkaline environment for the reaction to promote the redox reaction. After mixing evenly, measure 0.005 parts by mass of the oxidant hydrazine hydrate and add it dropwise, then continue to ultrasonicate for 15 min to obtain a hydrogel-like mixture;

[0051] Step 1.3, Add the hydrogel-like mixture into a constant temperature and constant pressure hydrothermal reaction kettle, seal it, set the maintenance temperature to 95 °C, the maintenance time to 120 min, and the heating-up time to 20 min;

[0052] Step 1.4, Filter the reacted mixed reagent with a 3M filter membrane, then filter it with a 0.45 μm filter membrane, and then wash it three times with deionized water to remove the residual ammonia water, and further wash it with an alcohol solution and replace the aqueous solution to shorten the freeze-drying time;

[0053] Step 1.5, Put the filtered and washed solid part into a round reagent kit, freeze it at -20 °C for 2 h, then transfer it to -80 °C and freeze for 4 h to be completely shaped. Subsequently, place the freeze-dried sample in a freeze-dryer and freeze it at -60 °C for 24 h to obtain the reduced graphene oxide aerogel to be measured;

[0054] Step 1.6, Measure the thermal conductivity λ of the reduced graphene oxide aerogel to be measured in the horizontal direction h1 and the thermal conductivity λ in the vertical direction v1 , when λ h1 / λ v1 <10, then return to Step 1.2, increase the proportion of hydrazine hydrate by a gradient of 0.002 parts by mass up to 0.007 parts by mass, and cycle Steps 1.2 to 1.5. If still λ h1 / λ v1 <10, then return to Step 1.2 again, continue to increase the proportion of hydrazine hydrate by a gradient of 0.002 parts by mass, and the mass part of hydrazine hydrate does not exceed 0.01, and cycle Steps 1.2 to 1.5 until λ h1 / λ v1 >10, end the cycle to obtain a reduced graphene oxide aerogel (RGO) with excellent thermal performance.

[0055] Step 2, Preparation of aniline sol, which consists of the following components by mass: 2.796 parts by mass of aniline monomer and 1.825 parts by mass of 1 mol / L hydrochloric acid solution. The specific steps are as follows:

[0056] Step 2.1, Weigh 18 mL of hydrochloric acid solution into a beaker, stir with a glass rod and slowly add 150 mL of distilled water. Place the mixed solution in a 200 mL volumetric flask, and then add distilled water to make up to 200 mL after cooling. Shake well to obtain 200 mL of 1 mol / L hydrochloric acid solution;

[0057] Step 2.2, Weigh 2.796 parts by mass of aniline monomer and add it to 1.825 parts by mass of 1 mol / L hydrochloric acid solution. Ultrasonically treat the mixed solution in the range of 0 - 4 °C for 10 min. After it is dissolved evenly, transfer it to an ice bath environment and stir at a speed of 300 rpm for 20 min, keeping the temperature below 4 °C to obtain aniline sol, and maintain the continuous ice bath environment.

[0058] Step 3, According to the mass ratio of aniline to reduced graphene oxide aerogel of m Aniline :m RGO = 1:(0.05 - 0.5), weigh 0.05 parts by mass of reduced graphene oxide aerogel and 1 part by mass of aniline, and fully dissolve them in 1.825 parts by mass of 1 mol / L hydrochloric acid solution. Ultrasonically mix for 10 min until evenly mixed, and add the obtained mixed solution to the aniline sol prepared in Step 2 for reaction. Stir at a speed of 300 rpm in an ice bath environment for 30 min to obtain an aniline-reduced graphene oxide aerogel hybrid system, where the reduced graphene oxide aerogel serves as the carrier framework;

[0059] Step 4, Sol-gelation. Dissolve 6.846 parts by mass of oxidant ammonium persulfate in 3.65 parts by mass of 1 mol / L hydrochloric acid solution, stir at a speed of 300 rpm for 10 min, and add it to the aniline-reduced graphene oxide aerogel hybrid system for gelation and polymerization reactions. Stir at a speed of 300 rpm in an environment of 0 - 4 °C for 7 h;

[0060] Step 5, Post-treatment of polyaniline-reduced graphene oxide composite aerogel. Filter the reaction product in Step 4 with a 3M filter membrane and a 0.45 μm filter membrane, wash it three times with distilled water, then perform displacement washing with an alcohol solution, refrigerate at -80 °C for 4 h, and then place it in a -60 °C freeze-drying oven for freeze-drying for 36 h to obtain the polyaniline-reduced graphene oxide composite aerogel to be tested;

[0061] Step 6, Measure the thermal conductivity λ h2 in the horizontal direction and the thermal conductivity λv2 When λ h2 / λ v2 <6, return to step 3, increase the proportion of reduced graphene oxide aerogel by a gradient of 0.01 parts by mass to 0.06 parts by mass, and cycle steps 3 to 5. If λ h2 / λ v2 <6 is still measured, then return to step 3 again, increase the proportion of reduced graphene oxide aerogel by a gradient of 0.01 parts by mass, and the mass fraction of reduced graphene oxide aerogel does not exceed 0.5, and cycle steps 3 to 5. If λ h2 / λ v2 >6 is measured, then perform thermogravimetric analysis test under nitrogen atmosphere, keep the heating rate at 10 °C / min, when the temperature rises from room temperature to 400 °C, if the mass loss rate W satisfies W>12%, then return to step 3 again, increase the proportion of reduced graphene oxide aerogel by a gradient of 0.01 parts by mass, and cycle steps 3 to 5 until λ h2 / λ v2 >6 and W<12%, end the cycle to obtain polyaniline-reduced graphene oxide composite aerogel (RGP);

[0062] Step 7, synthesis of high-temperature resistant polyurethane matrix coating containing fillers. Adjust the ratio of hard and soft segments between polyester chain segments and diisocyanate chains in polyurethane by chain extender MOCA with different ratios to improve thermal stability. Based on the method of mixing chain extender MOCA, polyurethane prepolymer, and ethyl acetate in a mass ratio of m MOCA :m PPU :m EAC =5~30:100:100 and performing ultrasonic polycondensation to obtain a high-temperature resistant polyurethane matrix coating, specifically:

[0063] Weigh 5 - 30 parts by mass of MOCA, seal it, and heat it on a heating table at 120 °C until it melts. Weigh 100 parts by mass of polyurethane prepolymer, seal it, and heat it on a heating table at 70 °C until it melts. Use polyaniline-reduced graphene oxide composite aerogel as a filler, dissolve the polyaniline-reduced graphene oxide composite aerogel in 100 parts by mass of ethyl acetate solution, where the mass ratio of polyaniline-reduced graphene oxide composite aerogel to ethyl acetate is m RGP :m EAC =(0.01~0.03):1, ultrasonically mix for 15 min, add the mixed reagent to the melted polyurethane prepolymer and ultrasonically mix again for 15 min. Finally, add the melted MOCA to the mixed reagent and stir until it is evenly mixed to obtain a high-temperature resistant polyurethane matrix coating containing fillers, that is, graphene-based aerogel high-temperature resistant and corrosion-resistant organic coating.

[0064] It should be noted that 0.4 - 1 mL of the above-mentioned graphene-based aerogel high-temperature resistant and corrosion-resistant organic coating is measured using a dropper, and it is evenly coated on the pretreated metal surface within 10 minutes, and left standing at room temperature for 48 hours to obtain a high-temperature resistant and corrosion-resistant coating with a thickness of 40 - 100 μm;

[0065] Among them, the metal sample material is Q235 steel, with dimensions of 20 * 20 * 2 mm. The surface is pretreated by sandblasting and surface rinsed with alcohol to remove oil stains. It can also be used for coating metal materials such as aluminum and copper.

[0066] Example 2

[0067] Prepare polyaniline-reduced graphene oxide composite aerogel using the preparation method of the graphene-based aerogel organic coating described in Example 1, including:

[0068] Step 1, prepare reduced graphene oxide aerogel by using hydroxylated graphene oxide, deionized water, ammonia water with a concentration of 25% - 28%, and oxidant hydrazine hydrate. Specifically:

[0069] Step 1.1, measure 0.9 parts by mass of hydroxylated graphene oxide and 0.3 parts by mass of deionized water, prepare a graphene oxide gel solution with a concentration of 3 mg / mL, place it in an ultrasonic dispersion instrument and ultrasonicate for 20 minutes. During the ultrasonic process, control the temperature of the water tank with circulating ice water not to exceed 15 °C. After sufficient dispersion, a homogeneous solution is obtained;

[0070] Step 1.2, place the homogeneous solution above a magnetic stirrer, maintain the rotation speed at 300 rpm, use a pipette to gradually add 0.018 parts by mass of ammonia water with a concentration of 25% - 28% dropwise to the homogeneous solution and stir for 5 minutes. The ammonia water provides an alkaline environment for the reaction to promote the redox reaction. After mixing, measure 0.005 parts by mass of oxidant hydrazine hydrate and add it dropwise, and continue ultrasonication for 15 minutes to obtain a hydrogel-like mixture;

[0071] Step 1.3, add the hydrogel-like mixture to a constant temperature and pressure hydrothermal reaction kettle, seal it, set the maintenance temperature at 95 °C, the maintenance time at 120 minutes, and the heating-up time at 20 minutes;

[0072] Step 1.4, filter the reacted mixed reagent using a 3M filter membrane, then use a 0.45 μm filter membrane, and then wash it three times with deionized water to remove the residual ammonia water, and further wash it with an alcohol solution and replace the aqueous solution to shorten the freeze-drying time;

[0073] Step 1.5: Put the solid part after filtration and washing into a round reagent kit, freeze it at -20°C for 2 h, then transfer it to -80°C for 4 h for complete shaping. Subsequently, place the freeze-dried sample in a freeze-dryer and freeze it at -60°C for 24 h to obtain the reduced graphene oxide aerogel to be measured;

[0074] Step 1.6: Measure the thermal conductivity λ of the reduced graphene oxide aerogel to be measured in the horizontal direction by a thermal conductivity meter h1 and the thermal conductivity λ in the vertical direction v1 . When λ h1 / λ v1 <10, return to Step 1.2, increase the proportion of hydrazine hydrate by a gradient of 0.002 parts by mass to 0.007 parts by mass, and cycle Steps 1.2 to 1.5. If λ h1 / λ v1 <10 is still measured, then return to Step 1.2 again, continue to increase the proportion of hydrazine hydrate by a gradient of 0.002 parts by mass, and the mass fraction of hydrazine hydrate does not exceed 0.01, and cycle Steps 1.2 to 1.5 until λ h1 / λ v1 >10, and end the cycle;

[0075] When the mass fraction of hydrazine hydrate is 0.009, λ h1 / λ v1 >10 is measured by a thermal conductivity meter, that is, a reduced graphene oxide aerogel (RGO) with excellent thermal performance is prepared;

[0076] Step 2: Preparation of aniline sol, which consists of the following components in parts by mass, where 2.796 parts by mass of aniline monomer and 1.825 parts by mass of 1 mol / L hydrochloric acid solution;

[0077] Step 3: According to the mass ratio of aniline to the reduced graphene oxide aerogel of m Aniline :m RGO =1:(0.05 - 0.5), first weigh 0.05 parts by mass of the reduced graphene oxide aerogel and 1 part by mass of aniline (different ratios of the skeleton material and the load form differences in heat transfer performance, mechanical properties and structure), and fully dissolve the reduced graphene oxide aerogel and aniline in 1.825 parts by mass of 1 mol / L hydrochloric acid solution, ultrasonically mix for 10 min to be uniform, and react the mixed solution with the above aniline sol, and stir at a rotation speed of 300 rpm for 30 min in an ice bath environment to obtain an aniline-reduced graphene oxide aerogel mixed system, where the reduced graphene oxide aerogel serves as the carrier skeleton and provides rich sites for the attachment of polyaniline;

[0078] Step 4, Sol-gelation: Weigh 6.846 parts by mass of the oxidant ammonium persulfate and dissolve it in 3.65 parts by mass of 1 mol / L hydrochloric acid solution. Stir at a rotation speed of 300 rpm for 10 min, and add it to the aniline-reduced graphene oxide aerogel mixed system for gelation and polymerization reactions. Stir at 300 rpm for 7 h in an environment of 0 - 4°C;

[0079] Step 5: Filter the mixed solution after the reaction is completed with a 3M filter membrane, then filter it with a 0.45 μm filter membrane. Wash it three times with distilled water to remove the residual ammonium persulfate, and further wash it with an alcohol solution and replace the aqueous solution. Put the solid part after filtration and washing into a round reagent kit, and place it at -80°C Refrigeration After 4 h, place it in a freeze-drying oven at -60°C Freezing For 36 h to obtain the to-be-tested polyaniline-reduced graphene oxide composite aerogel;

[0080] Step 6: Measure the thermal conductivity λ in the horizontal direction of the to-be-tested polyaniline-reduced graphene oxide composite aerogel with a thermal conductivity meter h2 and the thermal conductivity λ in the vertical direction v2 , when λ h2 / λ v2 <6, then return to Step 3, increase the proportion of reduced graphene oxide aerogel by a gradient of 0.01 part by mass up to 0.06 part by mass, and cycle Steps 3 to 5. If it is still measured that λ h2 / λ v2 <6, then return to Step 3 again, increase the proportion of reduced graphene oxide aerogel by a gradient of 0.01 part by mass, and the mass part of the reduced graphene oxide aerogel does not exceed 0.5, and cycle Steps 3 to 5. If it is measured that λ h2 / λ v2 >6, then conduct a thermogravimetric analysis test under a nitrogen atmosphere. Keep the heating rate at 10°C / min. When the temperature rises from room temperature to 400°C, when the mass loss rate W satisfies W>12%, then return to Step 3 again, increase the proportion of reduced graphene oxide aerogel by a gradient of 0.01 part by mass, and cycle Steps 3 to 5 until λ h2 / λ v2 >6 and W<12%, and end the cycle;

[0081] When the mass ratio of aniline to reduced graphene oxide aerogel is m Aniline : m RGO =1:0.2, that is, when using 1 part by mass of aniline and 0.2 part by mass of reduced graphene oxide aerogel, it is measured that λ h2 / λ v2 >6 and W<12%, that is, the polyaniline-reduced graphene oxide composite aerogel (RGP) is prepared.

[0082] The polyaniline-reduced graphene oxide composite aerogel, reduced graphene oxide aerogel, and graphene oxide obtained above were subjected to structural characterization:

[0083] Figures 2 to 4 Figure [0000269] is the scanning electron microscope image of the prepared material. It can be observed that graphene oxide has a weakly exfoliated sheet structure, and most of it remains as an adhered block layer structure. Figure 2 Figure [0000270] is the SEM image of the reduced graphene oxide aerogel. It can be significantly observed that a dense sheet structure forms a uniformly distributed network structure through the redox reaction. The sheets are very thin, presenting a large specific surface area and providing abundant attachment sites. Combining Figure [0000271] and Figure [0000272], it can be found that the polyaniline aerogel is uniformly attached to the surface of the reduced graphene oxide aerogel, presenting a columnar structure with burrs and showing certain spatially dispersed pores. In the energy spectrum diagram, the C atoms are the most concentrated, indicating that the C atom content is the most abundant. This comes from the C in the framework structure of the reduced graphene oxide aerogel and the C in the surface-attached polyaniline aerogel. The O element is mainly the residue after the redox reaction of hydrazine hydrate and ammonium persulfate. After washing, the N element mainly comes from the polyaniline structure attached to the surface layer. Combining the infrared spectrum (Figure [0000273]) and XRD (Figure [0000274]) which show the common characteristic peaks representing polyaniline and graphene-based materials, it indicates that the polyaniline-reduced graphene oxide composite aerogel was successfully prepared. Figure 3 Figure [0000271] is the SEM image of the reduced graphene oxide aerogel. It can be significantly observed that a dense sheet structure forms a uniformly distributed network structure through the redox reaction. The sheets are very thin, presenting a large specific surface area and providing abundant attachment sites. Combining Figure [0000271] and Figure [0000272], it can be found that the polyaniline aerogel is uniformly attached to the surface of the reduced graphene oxide aerogel, presenting a columnar structure with burrs and showing certain spatially dispersed pores. In the energy spectrum diagram, the C atoms are the most concentrated, indicating that the C atom content is the most abundant. This comes from the C in the framework structure of the reduced graphene oxide aerogel and the C in the surface-attached polyaniline aerogel. The O element is mainly the residue after the redox reaction of hydrazine hydrate and ammonium persulfate. After washing, the N element mainly comes from the polyaniline structure attached to the surface layer. Combining the infrared spectrum (Figure [0000273]) and XRD (Figure [0000274]) which show the common characteristic peaks representing polyaniline and graphene-based materials, it indicates that the polyaniline-reduced graphene oxide composite aerogel was successfully prepared. Figure 4 and Figure 5 Figure [0000272] shows that the polyaniline aerogel is uniformly attached to the surface of the reduced graphene oxide aerogel, presenting a columnar structure with burrs and showing certain spatially dispersed pores. In the energy spectrum diagram, the C atoms are the most concentrated, indicating that the C atom content is the most abundant. This comes from the C in the framework structure of the reduced graphene oxide aerogel and the C in the surface-attached polyaniline aerogel. The O element is mainly the residue after the redox reaction of hydrazine hydrate and ammonium persulfate. After washing, the N element mainly comes from the polyaniline structure attached to the surface layer. Combining the infrared spectrum (Figure [0000273]) and XRD (Figure [0000274]) which show the common characteristic peaks representing polyaniline and graphene-based materials, it indicates that the polyaniline-reduced graphene oxide composite aerogel was successfully prepared. Figure 6 ) and Figure 7 (XRD) show that the common characteristic peaks representing polyaniline and graphene-based materials indicate that the polyaniline-reduced graphene oxide composite aerogel was successfully prepared. Figure 8 Figure [0000276] is a physical picture of the polyaniline-reduced graphene oxide composite aerogel, with a loose and stable structure and low density (the shown block in the figure is 0.05 g).

[0084] Example 3

[0085] The high-temperature resistant polyurethane matrix coating without filler was prepared by using the preparation method of the graphene-based aerogel organic coating described in Example 1, including:

[0086] Step 1, the ratio of the hard and soft segments between the polyester chain segment and the diisocyanate chain in the polyurethane was adjusted by the chain extender MOCA with different ratios to improve the thermal stability. The mass ratio of the chain extender MOCA, polyurethane prepolymer, and ethyl acetate was mixed according to the ratio of m MOCA :m PPU :m EAC =(5, 15, 20, 25, 30):100:100, and five groups of high-temperature resistant polyurethane matrix materials were obtained by ultrasonic polycondensation for 10 min. Specifically:

[0087] Weigh 5 parts by mass of MOCA, seal it, and heat it on a heating table at 120°C until it melts. Weigh 100 parts by mass of polyurethane prepolymer, seal it, and heat it on a heating table at 70°C until it melts. Weigh 100 parts by mass of ethyl acetate reagent and mix it with the melted polyurethane prepolymer and stir evenly. Then add the melted MOCA to the mixed reagent, place it in an ultrasonic cell disruptor, and ultrasonicate it at 600W for 10 min until it is completely dispersed to obtain a group of high-temperature resistant polyurethane matrix coatings without fillers. Then, make four groups of high-temperature resistant polyurethane matrix coatings without fillers corresponding to the mass ratios of chain extender MOCA of 15, 20, 25, and 30 respectively.

[0088] Use a dropper to measure 0.8 mL of each of the above five groups of high-temperature resistant polyurethane matrix coatings without fillers, and evenly coat them on the pretreated metal surface within 10 min, and let them stand at room temperature for 48 h to prepare five groups of high-temperature resistant and corrosion-resistant coatings with a thickness of 80 μm.

[0089] Among them, the metal sample material is Q235 steel, with dimensions of 20×20×2 mm. The surface is pretreated by sandblasting and surface rinsed with alcohol to remove oil stains. It can also be used for coating on widely used metal materials such as aluminum and copper.

[0090] Conduct heat resistance tests on the above single coatings with different soft and hard segment ratios (i.e., five groups of high-temperature resistant polyurethane matrix coatings without fillers): Preheat an oven at 150 - 240°C for 30 min until the temperature distribution is uniform, place the dried coating in the oven and bake it for 30 min, and observe the surface color and blistering and damage phenomena of the coating.

[0091] The test results are as Figure 9 , where a, b, c, d, and e represent the weight components of MOCA as 5, 15, 20, 25, and 30 respectively. It can be found that after maintaining at 150°C for 30 min, cracks and bubbles appeared on the surface of the e-component coating. As the temperature increased to 200°C, the coatings of a-component and d-component showed cracks and bubbles to varying degrees. As the temperature increased to 220°C, the b-component coating could still maintain the integrity of the coating without color change and no blistering and peeling phenomenon after baking for 30 min, showing good mechanical properties. When the temperature increased to 230°C, the color of the b-component coating was significantly yellow compared with the control group. After baking at 240°C for 30 min, the coating completely failed, the coating became soft, showing high adhesion. Comprehensive comparison shows that the coating with the soft and hard segment ratio of b-component has excellent high-temperature resistance.

[0092] Example 4

[0093] Prepare graphene-based aerogel high-temperature resistant and corrosion-resistant organic coatings by using the preparation method of graphene-based aerogel organic coatings described in Example 1. It is composed of a polyaniline-reduced graphene oxide composite aerogel filler and a high-temperature resistant polyurethane matrix, including:

[0094] Step 1: Prepare the polyaniline-reduced graphene oxide composite aerogel according to the ratio that meets the conditions of thermal conductivity and thermogravimetric analysis in Example 2, that is, measure 0.9 parts by mass of hydroxylated graphene oxide, 0.3 parts by mass of deionized water, 0.018 parts by mass of ammonia water with a concentration of 25% - 28%, and 0.009 parts by mass of oxidant hydrazine hydrate to prepare the polyaniline-reduced graphene oxide composite aerogel;

[0095] Step 2: Prepare the high-temperature resistant polyurethane matrix according to the weight ratio with the best thermal stability obtained in Example 3 and mix it with the polyaniline-reduced graphene oxide composite aerogel (that is, prepare the high-temperature resistant polyurethane matrix coating containing fillers). Specifically:

[0096] Weigh 15 parts by mass of MOCA, seal it, and heat it on a heating table at 120°C until it melts. Weigh 100 parts by mass of polyurethane prepolymer, seal it, and heat it on a heating table at 70°C until it melts. The polyaniline-reduced graphene oxide composite aerogel is used as a filler. Dissolve the polyaniline-reduced graphene oxide composite aerogel in 100 parts by mass of ethyl acetate solution. Among them, the mass ratio of the polyaniline-reduced graphene oxide composite aerogel to ethyl acetate is m RGP :m EAC =(0.01 - 0.03):1. Ultrasonically mix for 15 min, add the mixed reagent to the melted polyurethane prepolymer and ultrasonically mix again for 15 min. Finally, add the melted MOCA to the mixed reagent and stir until evenly mixed. According to the mass ratio of the polyaniline-reduced graphene oxide composite aerogel to ethyl acetate being 1%, 2%, and 3% respectively (that is, the mass ratios are 0.01:1, 0.02:1, and 0.03:1 respectively), three groups of graphene-based aerogel high-temperature resistant and corrosion-resistant organic coatings are obtained.

[0097] Use a dropper to measure 0.8 mL of the above three components of graphene-based aerogel high-temperature resistant and corrosion-resistant organic coatings respectively, and evenly coat them on the pretreated metal surface within 10 min. Let it stand at room temperature for 48 h, and three groups of high-temperature resistant and corrosion-resistant coatings with a thickness of 80 μm are prepared; then use a dropper to measure 0.8 mL of the filler-free high-temperature resistant polyurethane matrix coating with the chain extender MOCA weight component of 15 in Example 3, evenly coat it on the pretreated metal surface within 10 min, and let it stand at room temperature for 48 h to prepare a single-component coating without adding fillers;

[0098] Among them, the metal sample material is Q235 steel, with a size of 20×20×2 mm. The surface is pretreated by sandblasting and surface rinsed with alcohol to remove oil stains. It can also be used for coating on widely used metal materials such as aluminum and copper.

[0099] Corrosion and mechanical property tests were carried out on the three groups of graphene-based aerogel high-temperature resistant and corrosion-resistant organic coatings prepared above and a single-component coating without added fillers:

[0100] From Figure 10 It can be observed that for the single-component coating without added fillers, that is, the high-temperature resistant polyurethane matrix coating without fillers with a MOCA weight component of 15%, corrosion spots appeared at 120 h. As time extended, the corrosion situation gradually became severe, the corrosion area and corrosion depth increased significantly, and the coating failed. For the coating with polyaniline-reduced graphene oxide composite aerogel added, the earliest corrosion spots appeared at 360 h with an addition amount of 3%. The corrosion gradually penetrated. When the content of polyaniline-reduced graphene oxide composite aerogel was 1% and 2%, the corrosion spots appeared at 528 h and 672 h respectively, indicating that when the content of polyaniline-reduced graphene oxide composite aerogel was 2%, a relatively good anti-corrosion effect could be achieved. From Figure 11 It can be directly seen from the polarization curve that after adding 2% of RGP filler, the corrosion potential shifted positively, the corrosion current density was the lowest, and the corrosion resistance was the best. The coating with 1% RGP filler added had the second-best corrosion resistance. Figure 12 Figure is the electrochemical impedance diagram for different RGP addition amounts. The larger the diameter of the semi-circle arc, the larger the electrochemical impedance value, and the more difficult it is for corrosion to occur. The experimental results for 28 days are consistent with Figure 11 the results of the polarization curve. The anti-corrosion ability from large to small is 2% RGP > 1% RGP > 3% RGP, and the electrochemical impedance value ranges from 8.8×10 -9 ~1.8×10 -8 Ω·cm -2 . Temperature resistance tests were carried out on the three groups of graphene-based aerogel high-temperature resistant and corrosion-resistant organic coatings with different RGP contents in a drying environment at 200 °C for 30 min and 15 cycles of alternating hot and cold at room temperature. The results are shown in Figure 13 . When the addition amount of RGP was 1%, messy cracks appeared on the coating surface, the coating surface was damaged, and the coating protection failed. When the addition amount of RGP was 3%, some pores appeared on the coating surface, which might be caused by excessive filler content. For the coating with 2% RGP added, no peeling or blistering and other phenomena occurred on the surface morphology, and the protection performance was good.

[0101] In summary, the present invention significantly improves the high-temperature resistant and corrosion-resistant performance of the coating by adding polyaniline-reduced graphene oxide composite aerogel filler to the polyurethane organic coating. The ratio of the hard and soft segments of polyurethane directly affects its thermal stability. By adding different ratios of chain extender MOCA, the interaction between the polyester chain segments and the diisocyanate chains, such as hydrogen bond interaction, is adjusted to improve the thermal stability of the material. In addition, the rigid structure after adding the hard segment can build a denser coating to effectively resist corrosion.

[0102] Secondly, the reduced graphene oxide aerogel has a unique sheet structure, and these sheets are interconnected to form a three-dimensional porous network, which makes the thermal conductivity of the reduced graphene oxide aerogel in the horizontal direction much greater than that in the vertical direction. This enables it to quickly conduct and diffuse heat in the horizontal direction, reducing the local accumulation of heat in the coating and effectively inhibiting the thermal decomposition and carbonization of the coating. At the same time, the air-filled pores in the three-dimensional porous structure play a good heat insulation role, further enhancing the high-temperature resistance performance of the coating. In terms of anti-corrosion, the sheet structure of the reduced graphene oxide aerogel has a strong barrier effect on corrosive media. When corrosive media attempt to penetrate the coating, they need to diffuse along the tortuous path between the sheets, greatly increasing the diffusion resistance and prolonging the time for the corrosive media to reach the substrate, thereby significantly improving the anti-corrosion performance of the coating.

[0103] Polyaniline aerogel has a unique molecular chain structure and nano-porous structure. Its conjugated π-bond body can absorb and disperse energy, slowing down the thermal degradation rate of the molecular chain, thereby improving the high-temperature resistance performance of the coating. At the same time, the polar groups on the molecular chain can form strong interactions with organic resin molecules, enhancing the overall stability of the coating. Its rich nano-porous structure can, on the one hand, store low-thermal-conductivity media such as air to form a good heat insulation layer to block the transfer of heat; on the other hand, these nano-scale pores and tortuous pore structures have a strong physical barrier effect on corrosive media, making it difficult for corrosive media to penetrate to the substrate, improving the anti-corrosion performance of the coating. In addition, polyaniline itself has certain redox activity. In a corrosive environment, it can consume some corrosive media through its own redox reaction, playing a role in chemical protection and further protecting the organic resin substrate and the material to be protected.

[0104] The synergistic effect between the reduced graphene oxide and polyaniline makes the structure of the composite aerogel more dense, significantly enhancing the barrier ability to corrosive media. In addition, the reduced graphene oxide aerogel is prone to agglomeration. Using the reduced graphene oxide aerogel as a framework support structure, the polyaniline aerogel with good surface structure and functional characteristics can effectively disperse the reduced graphene oxide aerogel, which has a significant synergistic effect on achieving uniform dispersion and further enhancing the corrosion resistance of the coating.

[0105] The coating described in the present invention is suitable for application in environments with high temperature, high salt, and high humidity. The high-temperature limit does not exceed 200 °C. At 200 °C, it can maintain the integrity of the coating without color change, blistering, or peeling for 30 min, and has good mechanical properties.

[0106] The high-temperature and corrosion-resistant organic coating described in the present invention can achieve an anti-corrosion time of 360 - 672 h in a 3.5 wt% sodium chloride solution, and the electrochemical impedance ranges from 8.8×10 -9 ~1.8×10 -8 Ω·cm -2。

[0107] Although embodiments of the present invention have been shown and described, those of ordinary skill in the art will appreciate that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A preparation method of a graphene-based aerogel organic coating, characterized in that, Including the following steps: Step 1, preparation of reduced graphene oxide aerogel: Mix hydroxylated graphene oxide, deionized water, oxidant hydrazine hydrate, and ammonia water with a concentration of 25% - 28% in a constant temperature and pressure hydrothermal reaction kettle, maintain at 95°C for 120 min for the redox process. After the reaction, filter and wash, refrigerate at -80°C for 4 h, and then place in a -60°C freeze-drying oven for freeze-drying for 24 h to obtain reduced graphene oxide aerogel. Specifically: Step 1.1, measure 0.9 mass parts of hydroxylated graphene oxide and 0.3 mass parts of deionized water, prepare a graphene oxide gel solution with a concentration of 3 mg / mL, place it in an ultrasonic dispersion instrument and ultrasonic for 20 min. During the ultrasonic process, control the temperature of the circulating ice water in the water tank not to exceed 15°C to obtain a homogeneous solution; Step 1.2, place the homogeneous solution above a magnetic stirrer, keep the rotation speed at 300 rpm, use a pipette to suck 0.018 mass parts of ammonia water with a concentration of 25% - 28% and add it dropwise to the homogeneous solution and stir for 5 min. The ammonia water provides an alkaline environment for the reaction to promote the redox reaction. After mixing, measure 0.005 mass parts of oxidant hydrazine hydrate and add it dropwise, and continue to ultrasonic for 15 min to obtain a hydrogel-like mixture; Step 1.3, add the hydrogel-like mixture to a constant temperature and pressure hydrothermal reaction kettle, seal it, set the maintenance temperature at 95°C, the maintenance time at 120 min, and the heating time at 20 min; Step 1.4, filter the reacted mixed reagent with a 3M filter membrane, then filter with a 0.45 μm filter membrane, wash three times with deionized water to remove the residual ammonia water, and further wash with an alcohol solution and replace the aqueous solution to shorten the freeze-drying time; Step 1.5, put the filtered and washed solid part into a round reagent kit, freeze at -20°C for 2 h, then transfer to -80°C for 4 h to be completely shaped. Subsequently, place the freeze-dried sample in a freeze-drying oven and freeze at -60°C for 24 h to obtain the reduced graphene oxide aerogel to be measured; Step 1.6, measure the thermal conductivity λ of the reduced graphene oxide aerogel to be measured in the horizontal direction by a thermal conductivity meter h1 and the thermal conductivity λ in the vertical direction v1 , when λ h1 / λ v1 <10, return to Step 1.2, increase the proportion of hydrazine hydrate by a gradient of 0.002 parts by mass to 0.007 parts by mass, and cycle Steps 1.2 to 1.

5. If λ h1 / λ v1 <10 is still measured, then return to Step 1.2 again, continue to increase the proportion of hydrazine hydrate by a gradient of 0.002 parts by mass, and the mass part of hydrazine hydrate does not exceed 0.01, and cycle Steps 1.2 to 1.5 until λ h1 / λ v1 >10, end the cycle, and obtain the reduced graphene oxide aerogel; Step 2, preparation of aniline sol: Mix 2.796 mass parts of aniline monomer with 1.825 mass parts of 1 mol / L hydrochloric acid solution, ultrasonic for 30 min at 0 - 4°C to obtain aniline sol, and maintain a continuous ice bath environment; Step 3, weigh 0.05 mass parts of reduced graphene oxide aerogel and 1 mass part of aniline, and fully dissolve them in 1.825 mass parts of 1 mol / L hydrochloric acid solution, ultrasonic for 10 min to mix evenly, and add the obtained mixture to the aniline sol prepared in Step 2 for reaction, stir at 300 rpm for 30 min in an ice bath environment to obtain an aniline-reduced graphene oxide aerogel hybrid system, where the reduced graphene oxide aerogel serves as the carrier skeleton; Step 4, Sol-gelation: Dissolve 6.846 parts by mass of the oxidant ammonium persulfate in 3.65 parts by mass of 1 mol / L hydrochloric acid solution, stir at a rotation speed of 300 rpm for 10 min, and add it to the aniline-reduced graphene oxide aerogel mixed system for gelation and polymerization reaction. Stir at a rotation speed of 300 rpm for 7 h in an environment of 0 - 4°C. Step 5, Filter the reaction product in Step 4 with a 3M filter membrane and a 0.45 μm filter membrane, wash it three times with distilled water, then perform displacement washing with an alcohol solution, refrigerate at -80°C for 4 h, and then place it in a freeze-drying oven at -60°C for 36 h to obtain the polystyrene-reduced graphene oxide composite aerogel to be tested. Step 6, measure the thermal conductivity λ of the polyaniline-reduced graphene oxide composite aerogel to be measured in the horizontal direction by a thermal conductivity meter h2 and the thermal conductivity λ in the vertical direction v2 . When λ h2 / λ v2 <6, return to Step 3, increase the proportion of the reduced graphene oxide aerogel by a gradient of 0.01 parts by mass to 0.06 parts by mass, and cycle Steps 3 to 5. If λ h2 / λ v2 <6 is still measured, then return to Step 3 again, increase the proportion of the reduced graphene oxide aerogel by a gradient of 0.01 parts by mass, and the mass fraction of the reduced graphene oxide aerogel does not exceed 0.5, and cycle Steps 3 to 5. If λ h2 / λ v2 >6 is measured, then perform a thermogravimetric analysis test under a nitrogen atmosphere, keep the heating rate at 10 °C / min, and when the mass loss rate W satisfies W>12% when heating from room temperature to 400 °C, then return to Step 3 again, increase the proportion of the reduced graphene oxide aerogel by a gradient of 0.01 parts by mass, and cycle Steps 3 to 5 until λ h2 / λ v2 >6 and W<12%, end the cycle to obtain the polyaniline-reduced graphene oxide composite aerogel; Step 7, Synthesis of the high-temperature resistant polyurethane matrix coating containing fillers: Based on the method of mixing 5 - 30 parts by mass of the chain extender MOCA, 100 parts by mass of the polyurethane prepolymer, and 100 parts by mass of ethyl acetate and performing ultrasonic polycondensation to obtain the high-temperature resistant polyurethane matrix coating, specifically: Weigh 5 - 30 parts by mass of MOCA, seal it, and heat it on a heating table at 120°C until it melts. Weigh 100 parts by mass of the polyurethane prepolymer, seal it, and heat it on a heating table at 70°C until it melts. Use the polystyrene-reduced graphene oxide composite aerogel as a filler. Dissolve 1 - 3 parts by mass of the polystyrene-reduced graphene oxide composite aerogel in 100 parts by mass of ethyl acetate solution, ultrasonically mix it evenly for 15 min, add the mixed reagent to the melted polyurethane prepolymer and ultrasonically mix it evenly again for 15 min. Finally, add the melted MOCA to the mixed reagent and stir until it is evenly mixed to obtain the high-temperature resistant polyurethane matrix coating containing fillers, that is, the graphene-based aerogel high-temperature resistant and corrosion-resistant organic coating.

2. The preparation method of a graphene-based aerogel organic coating according to claim 1, characterized in that, The said Step 2 includes: Step 2.1, Weigh 18 mL of hydrochloric acid solution into a beaker, stir it with a glass rod and slowly add 150 mL of distilled water. Place the mixed solution in a 200 mL volumetric flask, and then add distilled water to make up the volume to 200 mL after cooling. Shake it well to obtain 200 mL of 1 mol / L hydrochloric acid solution. Step 2.2, Weigh 2.796 parts by mass of aniline monomer and add it to 1.825 parts by mass of 1 mol / L hydrochloric acid solution. Ultrasonically treat the mixed solution in the range of 0 - 4°C for 10 min. After it is dissolved evenly, transfer it to an ice bath environment and stir at a rotation speed of 300 rpm for 20 min, keeping the temperature below 4°C to obtain aniline sol, and maintain the continuous ice bath environment.

3. A graphene-based aerogel organic coating, characterized in that, Prepared by the preparation method of the graphene-based aerogel organic coating as described in Claim 1 or 2.

4. Application of the graphene-based aerogel organic coating as described in Claim 3 as a surface coating for any one of Q235 steel, aluminum alloy, and copper alloy.

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