An organic-inorganic hybrid anti-radiation and heat-insulating coating and a preparation method thereof

Abstract

The application discloses an organic-inorganic hybrid anti-radiation and heat insulation coating and a preparation method thereof, and relates to the technical field of coatings.The coating comprises, in percentage by mass, 25-45wt% of a film-forming base, 10-30wt% of silicon dioxide-coated gadolinium oxide composite particles, 3-15wt% of graphene oxide / mesoporous polydopamine / polyethylene glycol nano-filler, 2-10wt% of an additive, and the balance of deionized water; the film-forming base comprises a water-based polyurethane dispersion, a water-based epoxy emulsion and a water-based amine curing agent.The application also discloses a preparation method of the coating.The obtained coating has the advantages of heat insulation and buffering, anti-radiation, high adhesion, medium penetration resistance, water-based low VOC, sprayability, roll coatability and brush coatability, and can be used for medical protective boards, outer surfaces of industrial equipment and building protective components.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to an organic-inorganic hybrid anti-radiation and heat-insulating coating and its preparation method. Background Technology

[0002] With the rapid development of applications such as medical imaging protection, nuclear medicine auxiliary shielding, industrial flaw detection protection, external surface protection of heat source equipment, and building energy conservation, the market has placed higher demands on functional coating materials that combine heat insulation, radiation resistance, resistance to media penetration, and green construction performance. Especially in scenarios such as CT room perimeter wall panels, mobile protective screens, protective door surfaces, nuclear medicine auxiliary shielding panels, heat source equipment shells, and special protective enclosures, coatings not only need to reduce heat transfer and slow down surface temperature rise, but also need to have a certain attenuation effect on X-rays or gamma rays, while also possessing good adhesion, mechanical stability, and construction adaptability.

[0003] Existing thermal insulation coatings primarily reduce thermal conductivity by adding hollow glass microspheres, ceramic microspheres, aerogels, reflective pigments, or low thermal conductivity fillers, or by reflecting near-infrared radiation from sunlight to reduce heat accumulation. Other existing technologies introduce phase change materials to achieve heat absorption and release, forming a temperature buffer plateau to suppress short-term temperature rise peaks. While these technologies can improve thermal insulation performance to some extent, they mostly focus on a single mechanism of "low thermal conductivity" or "heat reflection," and do not adequately consider the sustainability of heat buffering after heating, resistance to media penetration, and compatibility with other functions, especially making it difficult to simultaneously meet radiation protection requirements.

[0004] On the other hand, existing radiation-resistant coatings or protective materials typically achieve X-ray or gamma-ray shielding by adding high-density, high-atomic-number fillers such as lead powder, barium sulfate, tungsten, bismuth oxide, and rare earth oxides to organic resins. Among these, lead-based materials, while offering good shielding performance, suffer from drawbacks such as high density, heavy environmental impact, and inconvenient construction.

[0005] Therefore, developing a multifunctional composite coating based on a water-based system that combines strong heat insulation, heat buffering, X / γ ray attenuation, good adhesion, resistance to media penetration, and sprayability has become an urgent technical problem to be solved in this field. Summary of the Invention

[0006] In view of this, the present invention provides an organic-inorganic hybrid anti-radiation and heat-insulating coating and its preparation method. The coating of the present invention, through the synergistic effect of its components, has the advantages of high thermal resistance, heat buffering, strong radiation shielding, high adhesion and excellent resistance to media.

[0007] To better solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0008] In a first aspect, an organic-inorganic hybrid radiation-resistant and heat-insulating coating comprises, by weight percentage, the following components:

[0009] The film-forming matrix is ​​25-45 wt%, silica-coated gadolinium oxide composite particles are 10-30 wt%, graphene oxide / mesoporous polydopamine / polyethylene glycol nanofiller is 3-15 wt%, additives are 2-10 wt%, and the balance is deionized water. The sum of the amounts of all components is 100%.

[0010] Preferably, the film-forming matrix comprises an aqueous polyurethane dispersion, an aqueous epoxy emulsion, and an aqueous amine curing agent, with a mass ratio of (15-30):(8-18):(2-8).

[0011] Preferably, the additives are a mixture of polyvinyl alcohol, silane coupling agent, polycarboxylate dispersant, thickener, and defoamer in a mass ratio of (1-5):(0.3-2):(0.2-1.5):(0.1-0.5):(0.1-0.5).

[0012] The solid content of the aqueous polyurethane dispersion is 35 wt%, and the solid content of the aqueous epoxy emulsion is 50 wt%.

[0013] Secondly, a method for preparing an organic-inorganic hybrid radiation-resistant and heat-insulating coating includes the following steps:

[0014] (1) Disperse gadolinium oxide powder in a mixed solution of ethanol and water to obtain gadolinium oxide dispersion; add tetraethyl orthosilicate, add ammonia water to adjust the pH, stir to carry out hydrolysis and condensation, then centrifuge, centrifuge the precipitate, wash and dry to obtain silica-coated gadolinium oxide composite particles.

[0015] (2) Add the graphene oxide dispersion to a mixture of ethanol and deionized water, add Tris buffer to adjust the pH to 8.5-9.0, then add dopamine monomer and pore-forming agent F127, and react under light-protected conditions to obtain graphene oxide / mesoporous polydopamine material; add the graphene oxide / mesoporous polydopamine material to a 10-25 wt% polyethylene glycol aqueous solution for impregnation treatment; finally centrifuge, wash, and freeze-dry to obtain graphene oxide / mesoporous polydopamine / polyethylene glycol nanofiller;

[0016] (3) Mix polyvinyl alcohol solution, deionized water and dispersant, stir once, then add silica-coated yttrium oxide nanoparticles, stir twice, then add graphene oxide / mesoporous polydopamine / polyethylene glycol nanofiller, stir three times, finally add silane coupling agent, adjust pH, let stand and mature to obtain primary slurry;

[0017] (4) Add the waterborne polyurethane dispersion to the above primary slurry and stir four times. Then add the waterborne epoxy emulsion and stir five times. Then add the defoamer and thickener and stir six times to adjust the viscosity of the system and obtain the functional slurry.

[0018] (5) Before use, mix the functional slurry and the water-based amine curing agent.

[0019] Preferably, in step (1), the mass ratio of gadolinium oxide powder, tetraethyl orthosilicate, anhydrous ethanol, deionized water, and ammonia is 190:(8-10):(25-30):4:1; the concentration of ammonia is 25-30wt%; the stirring speed for the stirring hydrolysis condensation is 300-400rpm, the time is 5-6h, and the temperature is room temperature.

[0020] Preferably, in step (2), the mass ratio of graphene oxide, dopamine monomer, pore-forming agent F127, and polyethylene glycol is (0.1-0.5):(3-8):(1-3):(5-10); and the molecular weight of polyethylene glycol is 1000-6000.

[0021] Preferably, in step (2), the temperature of the light-protected reaction is room temperature and the time is 8-16 hours.

[0022] Preferably, in step (2), the immersion treatment temperature is 40-60℃ and the time is 12-24h.

[0023] Preferably, in step (3), the conditions for the first stirring include: stirring speed of 300-500 rpm and stirring time of 5-10 min; the conditions for the second stirring include: stirring speed of 1200-2000 rpm and stirring time of 20-40 min; the conditions for the third stirring include: stirring speed of 1200-2000 rpm and stirring time of 15-30 min; the conditions for adjusting the pH to 7.5-8.5 and allowing it to stand for maturation include: room temperature and time of 20-60 min.

[0024] Preferably, in step (4), the conditions for the four stirrings include: stirring speed of 500-800 rpm and stirring time of 10-20 min; the conditions for the five stirrings include: stirring speed of 500-800 rpm and stirring time of 15-20 min; the conditions for the six stirrings include: stirring speed of 500-800 rpm and stirring time of 10-20 min; and adjusting the viscosity of the system to 3000-8000 mPa·s.

[0025] Compared with the prior art, the present invention has at least the following advantages:

[0026] 1. This invention incorporates graphene oxide / mesoporous polydopamine / polyethylene glycol nanofillers with silica-coated yttrium oxide nanoparticles into an organic coating matrix, enabling the coating to possess both thermal management capabilities and attenuation capabilities for X-rays and / or γ-rays.

[0027] 2. In the graphene oxide / mesoporous polydopamine / polyethylene glycol nanofiller of this invention, the graphene oxide sheets can construct tortuous heat and mass transport paths within the coating, the mesoporous polydopamine imparts good interfacial activity and photothermal response characteristics to the material, and the polyethylene glycol forms a thermal buffer platform through phase change endothermic and exothermic processes. These three materials synergistically enhance the coating's thermal regulation capability and thermal insulation durability. Furthermore, the two-dimensional barrier structure of the graphene oxide sheets, the dense network after waterborne epoxy curing, and the filling effect of the inorganic functional phase work together to effectively extend the diffusion paths of moisture, salt spray, corrosive media, and small molecules, enhancing the coating's resistance to media penetration. Therefore, this invention is not only suitable for radiation and thermal protection but also maintains good structural stability and protective effects in humid, corrosive, or alternating hot and cold environments.

[0028] 3. This invention incorporates a certain amount of silica-coated yttrium oxide nanoparticles into the coating, improving the coating's shielding continuity and overall shielding efficiency, while ensuring environmental friendliness and protective performance. The silica-coated yttrium oxide nanoparticles in this invention utilize a silica shell for surface coating, which significantly improves the interfacial compatibility and wetting / dispersion of high-yttrium oxide nanoparticles in aqueous resin systems, reducing direct agglomeration and hard contact between inorganic particles. The silica shell also helps increase interfacial scattering paths and forms a stable interface with the resin, polyvinyl alcohol, and silane coupling agent, thereby reducing the risk of sedimentation during coating storage and application, and improving the uniformity and stability of the coating film.

[0029] 4. This invention uses a waterborne polyurethane dispersion and a waterborne epoxy emulsion to construct a hybrid film-forming system. The waterborne polyurethane imparts good flexibility, impact resistance and substrate adaptability to the coating, while the waterborne epoxy provides high crosslinking density, adhesion and resistance to media penetration. The synergistic effect of the two matrices can effectively alleviate the embrittlement and cracking problems common in high filler systems, so that the resulting coating has both mechanical stability and barrier protection performance.

[0030] 5. This invention constructs a multi-scale interfacial coupling network through hydrogen bonding, interfacial intercalation, and coupling agent bridging among the functional groups on the surface of polyvinyl alcohol, silica shell, mesoporous polydopamine, and polar groups of epoxy and waterborne polyurethane. This network can enhance the interfacial bonding between each functional filler and the matrix, improve load transfer and stress dispersion, thereby increasing the adhesion of the coating to substrates such as metals, concrete, and composite panels, and reducing the risk of microcracks, delamination, and performance degradation during long-term service. Detailed Implementation

[0031] To further illustrate the technical means and effects of the present invention in achieving the intended purpose, the following detailed description of the specific implementation methods, structures, features and effects of the present invention, in conjunction with preferred embodiments, is provided below.

[0032] Unless otherwise specified, all raw materials used in the following examples and comparative examples are commercially available materials commonly used in the art.

[0033] Example 1

[0034] The preparation of the silica-coated gadolinium oxide composite particles includes the following steps:

[0035] 1. Weigh out gadolinium oxide powder (particle size 20-30nm, Zhejiang Yamei Nanotechnology Co., Ltd.), tetraethyl orthosilicate, anhydrous ethanol, deionized water and ammonia water with a concentration of 28wt% in a mass ratio of 190:9:28:4:1.

[0036] 2. First, add gadolinium oxide powder to a mixed solution composed of anhydrous ethanol and deionized water, and disperse it by mechanical stirring to obtain a gadolinium oxide dispersion. Then, add tetraethyl orthosilicate to the dispersion and add ammonia water dropwise to adjust the pH of the system. Stir at 350 rpm at room temperature for 5.5 h to hydrolyze and condense the mixture. After the reaction is completed, centrifuge the mixture and wash the precipitate with ethanol and deionized water 2-3 times in sequence. Then, dry it at 60℃ for 10 h to obtain silica-coated gadolinium oxide composite particles.

[0037] Example 2

[0038] The preparation of the graphene oxide / mesoporous polydopamine / polyethylene glycol nanofiller includes the following steps:

[0039] 1. Weigh out graphene oxide (sheet diameter 0.4-5μm, Jiangsu Xianfeng Nanomaterials Technology Co., Ltd.), dopamine monomer, pore-forming agent F127 and polyethylene glycol 2000 in a mass ratio of 0.3:5:2:8.

[0040] 2. First, add the graphene oxide dispersion to a mixture of ethanol and deionized water, add Tris buffer, and adjust the pH of the system to 8.8. Then, add dopamine monomer and porogen F127, and react at room temperature for 12 hours under light-protected conditions. After the reaction, centrifuge and wash to obtain graphene oxide / mesoporous polydopamine material. Then, add the obtained material to a 20wt% polyethylene glycol aqueous solution and impregnate at 50℃ for 18 hours. After impregnation, centrifuge, wash, and freeze-dry to obtain graphene oxide / mesoporous polydopamine / polyethylene glycol nanofiller.

[0041] Comparative Example 1

[0042] The difference between this example and Example 1 is that yttrium oxide powder is used directly without silica coating; the other operations are the same as in Example 1.

[0043] Comparative Example 2

[0044] The difference between this example and Example 2 is that it does not include mesoporous polydopamine, but the other operations are the same as in Example 1, resulting in graphene oxide / polyethylene glycol nanofiller.

[0045] Application Example 1

[0046] An organic-inorganic hybrid radiation-resistant and heat-insulating coating, by weight, comprises 28 parts of waterborne polyurethane dispersion (35wt% solid content, Guangdong Maoming Petrochemical Co., Ltd.); 10 parts of waterborne epoxy emulsion (50wt% solid content, Hansen Chemical Enterprise Management (Shanghai) Co., Ltd.); 3 parts of waterborne amine curing agent (EPIKURE 8537-WY-60, Hansen Chemical Enterprise Management (Shanghai) Co., Ltd.); 22 parts of silica-coated gadolinium oxide composite particles; 8 parts of graphene oxide / mesoporous polydopamine / polyethylene glycol nanofiller; 1.5 parts of polyvinyl alcohol; 0.8 parts of KH-560; 0.8 parts of polycarboxylate dispersant; 0.4 parts of thickener (Yalesun RM-8W); 0.5 parts of defoamer (BYK-012); and 25 parts of deionized water.

[0047] Its preparation method is as follows:

[0048] (1) First, prepare a 10wt% polyvinyl alcohol solution with some deionized water using ExcevalTMAQ4104, degree of alcoholysis 98%-99%, Shijiazhuang Tuochi Chemical Trade Co., Ltd.;

[0049] (2) Add the polyvinyl alcohol solution, the remaining deionized water and polycarboxylate dispersant to a dispersion container and stir at 400 rpm for 8 min; add the silica-coated gadolinium oxide composite particles prepared in Example 1 to the above system and stir at 1600 rpm for 30 min; then add the graphene oxide / mesoporous polydopamine / polyethylene glycol nanofiller prepared in Example 2 and stir at 1500 rpm for 20 min; add KH-560 to adjust the pH of the system to 8.0 and let it stand at room temperature for 30 min to obtain the primary slurry;

[0050] (3) Slowly add waterborne polyurethane dispersion to the primary slurry and stir at 600 rpm for 15 min; then add waterborne epoxy emulsion and stir at 600 rpm for 18 min; then add defoamer and thickener in sequence and stir at 600 rpm for 15 min, and adjust the viscosity of the system to 5000 mPa·s to obtain functional slurry;

[0051] (4) Before use, mix the functional slurry with the water-based amine curing agent and stir at a low speed of 300 rpm for 8 minutes. After degassing, the finished coating is obtained. Spray the obtained finished coating onto the surface of a steel plate (40mm×40mm×2mm, Q235 steel, Xinxiang Hongpeng Steel Co., Ltd.) that has been polished and degreased. Control the dry film thickness to 1.5mm. Surface dry at 25℃ for 2 hours, hard dry at 24 hours, and continue curing for 7 days to obtain a cured coating.

[0052] Application Example 2

[0053] An organic-inorganic hybrid radiation-resistant and heat-insulating coating, by weight, comprises 30 parts of waterborne polyurethane dispersion (35wt% solid content); 9 parts of waterborne epoxy emulsion (50wt% solid content); 3 parts of waterborne amine curing agent; 15 parts of silica-coated gadolinium oxide composite particles; 12 parts of graphene oxide / mesoporous polydopamine / polyethylene glycol nanofiller; 2 parts of polyvinyl alcohol; 0.8 parts of KH-560; 0.8 parts of polycarboxylate dispersant; 0.3 parts of thickener; 0.4 parts of defoamer; and 26.7 parts of deionized water.

[0054] The preparation method differs from that in Application Example 1 in that the final system viscosity is adjusted to approximately 4500 mPa·s, while other operations are the same as in Application Example 1.

[0055] Example 3

[0056] An organic-inorganic hybrid radiation-resistant and heat-insulating coating, by weight, comprises 23 parts of waterborne polyurethane dispersion (35wt% solid content); 9 parts of waterborne epoxy emulsion (50wt% solid content); 3 parts of waterborne amine curing agent; 30 parts of silica-coated gadolinium oxide composite particles; 5 parts of graphene oxide / mesoporous polydopamine / polyethylene glycol nanofiller; 1.5 parts of polyvinyl alcohol; 0.8 parts of KH-560; 0.8 parts of polycarboxylate dispersant; 0.4 parts of thickener; 0.5 parts of defoamer; and 26 parts of deionized water.

[0057] The difference between its preparation method and application example 1 is that: in step (2), the silica-coated gadolinium oxide composite particles prepared in example 1 are added to the above system and stirred at a speed of 1600 rpm for 35 min; in step (3), the viscosity of the system is adjusted to 6500 mPa·s, and other operations are the same as in application example 1.

[0058] Application Comparative Example 1

[0059] The difference between this example and Application Example 1 is that an equal amount of silica-coated gadolinium oxide composite particles are used instead of graphene oxide / mesoporous polydopamine / polyethylene glycol nanofillers. All other operations are the same as in Application Example 1.

[0060] Application Comparative Example 2

[0061] The difference between this example and Application Example 1 is that an equal amount of graphene oxide / mesoporous polydopamine / polyethylene glycol nanofiller is used to replace silica-coated gadolinium oxide composite particles; all other operations are the same as in Application Example 1.

[0062] Application Comparative Example 3

[0063] The difference between this example and Application Example 1 is that an equal amount of yttrium oxide powder from Comparative Example 1 is used to replace the silica-coated gadolinium oxide composite particles in Example 1. All other operations are the same as in Application Example 1.

[0064] Application Comparative Example 4

[0065] The difference between this example and Application Example 1 is that an equal amount of graphene oxide / polyethylene glycol nanofiller from Comparative Example 2 is used to replace the graphene oxide / mesoporous polydopamine / polyethylene glycol nanofiller in Example 2. All other operations are the same as in Application Example 1.

[0066] The functional coatings and cured coatings prepared in the above application examples and application comparison examples were tested.

[0067] I. Testing Method:

[0068] 1. Thermal conductivity: Tested according to GB / T 10294-2008 "Determination of steady-state thermal resistance and related properties of thermal insulation materials - protective hot plate method". The test temperature is 25℃, and the sample thickness is controlled at (1.5±0.2) mm to characterize the intrinsic thermal insulation capacity of the coating.

[0069] 2. Radiation resistance: The cured coating is cut to a specific size and tested using an X-ray tube with a voltage of 60-120 kV or using... 137 Cs、 60 The Co-γ-ray source was tested according to ASTM D4082-10(2023) "Standard Test Method for Gamma Radiation Effects of Coatings for Nuclear Power Plants". The intensity of incident and transmitted photons was measured by an energy dispersive spectrometer to calculate the lead equivalent (mmPb) of the coating under specific energy rays, or to calculate the mass attenuation coefficient.

[0070] 3. Adhesion: Tested according to GB / T 5210-2006 "Paints and Varnishes - Pull-off Adhesion Test".

[0071] 4. Chemical resistance: The test was conducted according to the immersion method in GB / T 9274-1988 "Determination of resistance to liquid media for paints and varnishes". The coated test plates were immersed in deionized water and 10wt% NaOH solution respectively at (23±2)℃, and the coating surface was observed to see if blistering, loss of gloss, softening, or peeling occurred.

[0072] 5. Pencil hardness: The surface hardness of the coating was determined according to GB / T 6739-2022 "Determination of Hardness of Paints and Varnishes by Pencil Method".

[0073] 6. Neutral salt spray resistance: Tested according to GB / T 1771-2007 "Determination of neutral salt spray resistance of paints and varnishes". After 500 hours of salt spray test in the crisscross state, observe the distance of corrosion spread on one side of the crisscross and the blistering and rusting of the coating.

[0074] II. Test Results and Analysis:

[0075] The test results are shown in Table 1.

[0076] Table 1

[0077] Thermal conductivity, W / m·K Radiation resistance (mmPb @100kV) Adhesion by pull-off method, MPa Water resistance, 240h Alkali resistance (10% NaOH, 168h) Salt spray resistance (500h, cross mark) Pencil hardness Application Example 1 0.035 0.32 6.8 No abnormalities No abnormalities The corrosion on one side of the scribing area is less than 1mm. 2H Application Example 2 0.038 0.24 6.2 No abnormalities No abnormalities The corrosion on one side of the scribing area is less than 1.5mm. H Application Example 3 0.042 0.41 5.9 No abnormalities No abnormalities The corrosion on one side of the scribing area is less than 1mm. 2H Application Comparative Example 1 0.058 0.38 4.5 Slight loss of light Slight bubbling The corrosion on one side of the scribed area is less than 2.5mm. H Application Comparative Example 2 0.052 0.05 5.1 No abnormalities Slight loss of light The corrosion on one side of the scribing area is less than 2mm. HB Application Comparative Example 3 0.048 0.18 3.2 Bubbling at the edges Noticeable bubbling The corrosion on one side of the scribing area is greater than 4mm. 2B Application Comparative Example 4 0.055 0.21 4.8 Slight loss of light Slight bubbling The corrosion on one side of the scribing area is less than 3mm. HB

[0078] As can be seen from the test results in Table 1, the organic-inorganic hybrid radiation-resistant and heat-insulating coatings prepared in Examples 1-3 of this invention exhibit excellent performance in terms of thermal conductivity, radiation resistance, adhesion, water resistance, alkali resistance, salt spray resistance, and surface hardness. This invention, through its organic-inorganic hybrid design, achieves synergistic heat insulation and radiation resistance while also ensuring excellent interfacial bonding strength and environmental stability.

[0079] Compared to Application Example 1, although Application Comparative Example 1 achieved a radiation resistance of 0.38 mmPb@100kV after replacing the graphene oxide / mesoporous polydopamine / polyethylene glycol nanofiller with an equal amount of silica-coated gadolinium oxide composite particles, indicating that increasing the content of radiation-resistant inorganic phase can improve the radiation attenuation capability to a certain extent, its thermal conductivity increased to 0.05 W / m·K, adhesion decreased to 4. MPa, and slight loss of gloss, slight blistering, and increased salt spray corrosion were observed. These results demonstrate that relying solely on high-density inorganic radiation-resistant fillers makes it difficult for coatings to simultaneously achieve thermal insulation, interfacial bonding strength, and long-term service stability. However, the introduction of graphene oxide / mesoporous polydopamine / polyethylene glycol nanofiller in this invention significantly improves the coating's thermal management capability and resistance to media penetration, thereby resulting in a coating with superior overall performance.

[0080] In Comparative Example 2, after replacing the silica-coated gadolinium oxide composite particles with an equal amount of graphene oxide / mesoporous polydopamine / polyethylene glycol nanofillers, the radiation resistance was significantly lower than that of the embodiments of the present invention. Simultaneously, its thermal conductivity, hardness, and salt spray resistance also decreased. This result indicates that while relying solely on graphene oxide / mesoporous polydopamine / polyethylene glycol nanofillers can improve the thermal insulation and barrier effects of the coating to some extent, it is insufficient to meet radiation protection requirements and is not conducive to achieving higher structural density and surface hardness. This further demonstrates that silica-coated gadolinium oxide composite particles are an indispensable key component for achieving radiation resistance in the present invention.

[0081] In Comparative Example 3, after replacing the silica-coated composite particles with uncoated inorganic powder, the thermal conductivity increased to 0.048 W / m·K, the radiation resistance decreased to 0.18 mmPb@100kV, the adhesion in the pull-out test was only 3.2 MPa, and edge blistering, significant blistering, and unilateral corrosion exceeding 4 mm at the scribing point were observed. The pencil hardness decreased to 2B. These results indicate that the silica shell plays an important role in improving the dispersibility, interfacial compatibility, and filler stability of inorganic particles in aqueous organic systems. Silica surface coating can reduce direct agglomeration and hard contact of inorganic particles, improve their wetting and dispersion effects in resin systems, and facilitate the formation of more stable interfacial bonds with polyvinyl alcohol, silane coupling agents, and resin polar groups, thereby significantly improving the coating's adhesion, resistance to media penetration, and salt spray resistance.

[0082] In Comparative Example 4, after replacing the graphene oxide / mesoporous polydopamine / polyethylene glycol nanofiller with graphene oxide / polyethylene glycol nanofiller, the thermal conductivity increased to 0.055 W / m·K, the radiation resistance decreased to 0.21 mmPb@100kV, the pull-off adhesion decreased to 4.8 MPa, and the water resistance, alkali resistance, and salt spray resistance all deteriorated. These results indicate that mesoporous polydopamine plays a crucial role in the nanofiller of this invention. On the one hand, mesoporous polydopamine provides a high specific surface area and abundant surface functional groups, which is beneficial for the loading and stability of polyethylene glycol and improves the phase transition heat buffering effect. On the other hand, its surface-active groups help enhance the interfacial interaction with graphene oxide and the organic resin matrix, thereby improving the filler dispersibility, interfacial adhesion, and overall coating density. Therefore, there is a significant synergistic reinforcing effect among graphene oxide, mesoporous polydopamine, and polyethylene glycol.

[0083] In summary, this invention introduces silica-coated gadolinium oxide composite particles and graphene oxide / mesoporous polydopamine / polyethylene glycol nanofillers into a waterborne polyurethane / waterborne epoxy hybrid film-forming system. This not only endows the coating with excellent thermal insulation properties and high X-ray and / or γ-ray attenuation capabilities, but also significantly improves the coating's adhesion, surface hardness, water resistance, alkali resistance, and salt spray resistance.

[0084] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. An organic-inorganic hybrid radiation-resistant and heat-insulating coating, characterized in that, It comprises the following components by weight percentage: The film-forming matrix consists of 25-45 wt% silica-coated gadolinium oxide composite particles, 10-30 wt% graphene oxide / mesoporous polydopamine / polyethylene glycol nanofiller, 3-15 wt% additives, and the balance being deionized water. The total amount of each component is 100%. The film-forming matrix includes an aqueous polyurethane dispersion, an aqueous epoxy emulsion, and an aqueous amine curing agent, with a mass ratio of (15-30):(8-18):(2-8).

2. The organic-inorganic hybrid anti-radiation and heat-insulating coating according to claim 1, characterized in that, The additives are a mixture of polyvinyl alcohol, silane coupling agent, polycarboxylate dispersant, thickener, and defoamer in a mass ratio of (1-5):(0.3-2):(0.2-1.5):(0.1-0.5):(0.1-0.5).

3. The method for preparing an organic-inorganic hybrid radiation-resistant and heat-insulating coating according to claim 1 or 2, characterized in that, Includes the following steps: (1) Disperse gadolinium oxide powder in a mixed solution of ethanol and water to obtain gadolinium oxide dispersion; add tetraethyl orthosilicate, add ammonia water to adjust the pH, stir to carry out hydrolysis and condensation, then centrifuge, centrifuge the precipitate, wash and dry to obtain silica-coated gadolinium oxide composite particles. (2) Add the graphene oxide dispersion to a mixture of ethanol and deionized water, add Tris buffer to adjust the pH to 8.5-9.0, then add dopamine monomer and pore-forming agent F127, and react under light-protected conditions to obtain graphene oxide / mesoporous polydopamine material; add the graphene oxide / mesoporous polydopamine material to a 10-25 wt% polyethylene glycol aqueous solution for impregnation treatment; finally centrifuge, wash, and freeze-dry to obtain graphene oxide / mesoporous polydopamine / polyethylene glycol nanofiller; (3) Mix polyvinyl alcohol solution, deionized water and dispersant, stir once, then add silica-coated yttrium oxide nanoparticles, stir twice, then add graphene oxide / mesoporous polydopamine / polyethylene glycol nanofiller, stir three times, finally add silane coupling agent, adjust pH, let stand and mature to obtain primary slurry; (4) Add the waterborne polyurethane dispersion to the above primary slurry and stir four times. Then add the waterborne epoxy emulsion and stir five times. Then add the defoamer and thickener and stir six times to adjust the viscosity of the system and obtain the functional slurry. (5) Before use, mix the functional slurry and the water-based amine curing agent.

4. The method for preparing an organic-inorganic hybrid radiation-resistant and heat-insulating coating according to claim 3, characterized in that, In step (1), the mass ratio of gadolinium oxide powder, tetraethyl orthosilicate, anhydrous ethanol, deionized water, and ammonia is 190:(8-10):(25-30):4:

1.

5. The method for preparing an organic-inorganic hybrid radiation-resistant and heat-insulating coating according to claim 3, characterized in that, In step (1), the concentration of the ammonia water is 25-30 wt%; the stirring speed for the stirring hydrolysis condensation is 300-400 rpm, the time is 5-6 h, and the temperature is room temperature.

6. The method for preparing an organic-inorganic hybrid radiation-resistant and heat-insulating coating according to claim 3, characterized in that, In step (2), the mass ratio of graphene oxide, dopamine monomer, pore-forming agent F127, and polyethylene glycol is (0.1-0.5):(3-8):(1-3):(5-10).

7. The method for preparing an organic-inorganic hybrid anti-radiation and heat-insulating coating according to claim 3, characterized in that, In step (2), the temperature of the light-protected reaction is room temperature, and the time is 8-16 hours.

8. The method for preparing an organic-inorganic hybrid anti-radiation and heat-insulating coating according to claim 3, characterized in that, In step (2), the immersion treatment temperature is 40-60℃ and the time is 12-24h.

9. The method for preparing an organic-inorganic hybrid anti-radiation and heat-insulating coating according to claim 3, characterized in that, In step (3), the conditions for the first stirring include: stirring speed of 300-500 rpm and stirring time of 5-10 min; the conditions for the second stirring include: stirring speed of 1200-2000 rpm and stirring time of 20-40 min; the conditions for the third stirring include: stirring speed of 1200-2000 rpm and stirring time of 15-30 min; the conditions for adjusting the pH to 7.5-8.5 and allowing it to stand for maturation include: room temperature and time of 20-60 min.

10. The method for preparing an organic-inorganic hybrid anti-radiation and heat-insulating coating according to claim 3, characterized in that, In step (4), the conditions for the four stirrings are: stirring speed of 500-800 rpm and stirring time of 10-20 min; the conditions for the five stirrings are: stirring speed of 500-800 rpm and stirring time of 15-20 min; the conditions for the six stirrings are: stirring speed of 500-800 rpm and stirring time of 10-20 min; and the viscosity of the system is adjusted to 3000-8000 mPa·s.