Super-tough ultraviolet-curable nano-reinforced aliphatic polyurea coating, elastomer and method of making and use thereof

Abstract

The application relates to an ultraviolet light-cured nanometer-reinforced aliphatic polyurea coating with super toughness, an elastomer thereof and a preparation method and application thereof, and relates to the field of aerospace coating applications. The ultraviolet light-cured nanometer-reinforced aliphatic polyurea coating with super toughness comprises an A component and a B component, further comprises an acrylic monomer, a photoinitiator and a graphene nanosheet. By adjusting the proportioning of the acrylic monomer and doping the graphene nanosheet, the ultraviolet light-cured nanometer-reinforced aliphatic polyurea coating with super toughness is prepared, and the mechanical performance of the ultraviolet light-cured nanometer-reinforced aliphatic polyurea elastomer is improved after ultraviolet light curing.

Description

Technical Field

[0001] This invention relates to the field of aerospace coatings, specifically to an ultra-tough UV-curable nano-reinforced aliphatic polyurea coating, its elastomer, preparation method, and application. Background Technology

[0002] 3D digital light processing (DLP) printing is a novel photopolymerization manufacturing technology that uses digital models as a basis to deposit materials layer by layer under the illumination of light of a certain wavelength to print three-dimensional objects. The curing mechanism of photosensitive resin in 3D printing involves the photoinitiator in the photosensitive resin system absorbing energy under the illumination of a light source of a certain wavelength, undergoing a photolysis reaction, and generating free radicals or superprotic acids. These two substances can activate the corresponding monomers and oligomers, activating and initiating the polymerization of oligomers and active monomers. Small molecules undergo cross-linking reactions to form polymers with photoinitiators. The active polymer can continuously activate and initiate the polymerization of oligomers and active monomers until it encounters another polymer with a photoinitiator or a polymerization inhibitor, at which point the polymerization reaction stops, and a polymeric solidified product is formed. Compared to other 3D printing methods, DLP printing technology has a faster forming speed and also has advantages such as ultra-high printing accuracy, clear texture of the finished product, and a highly textured visual effect. However, materials printed with photopolymer resin are greatly affected by ultraviolet light due to prolonged exposure, resulting in poor mechanical properties.

[0003] Aliphatic polyurea is a high-performance elastomer formed by the reaction of aliphatic isocyanate components and amino compound components. Due to its excellent weather resistance and mechanical properties, it has wide applications in the aerospace field. However, existing research on photocurable aliphatic polyurea elastomers is limited, and their performance is relatively poor, failing to meet the actual development needs of industrial applications.

[0004] Graphene, as a typical conductive two-dimensional monolayer carbon nanomaterial, possesses excellent mechanical, thermal, and electrical properties. However, its poor light transmittance limits its application in the field of photopolymerization technology. The performance of photopolymerizable materials directly affects the quality, mechanical properties, and precision of the molded parts, as well as whether the three-dimensional structure can be formed during the photopolymerization process. Therefore, preparing a photopolymerizable nano-reinforced aliphatic polyurea resin with good mechanical properties is an important research topic for promoting the development of photopolymerization technology. Summary of the Invention

[0005] In view of this, the present invention proposes an ultra-tough UV-curable nano-reinforced aliphatic polyurea coating, its elastomer, preparation method, and application. This method improves the mechanical properties of the UV-curable nano-reinforced aliphatic polyurea elastomer by adjusting the ratio of acrylic monomers and doping with graphene nanosheets.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] The present invention discloses an ultra-tough UV-curable nano-reinforced aliphatic polyurea coating, the raw materials of which include component A and component B, and also include acrylic monomer, photoinitiator and graphene nanosheets, wherein the acrylic monomer accounts for 5.84% to 6.89% of the mass percentage of the raw materials of the ultra-tough UV-curable nano-reinforced aliphatic polyurea coating.

[0008] The photoinitiator accounts for 6.19% to 7.91% of the mass percentage of the ultra-tough UV-curable nano-reinforced aliphatic polyurea coating raw material.

[0009] The graphene nanosheets constitute 0.1% to 0.5% of the mass of the ultra-tough UV-curable nano-reinforced aliphatic polyurea coating raw material.

[0010] The ultra-tough UV-curable nano-reinforced aliphatic polyurea coating raw material also includes a solvent, with the balance being a solvent.

[0011] The acrylic monomer is preferably at least two of the following: ethyl acrylate (EA), arginine acrylate (AA), isopentyl acrylate (IAA), hydroxyethyl methacrylate (HEMA), ethyl 2-(tert-butylamine) methacrylate (TBEMA), and 3,3,5-trimethylcyclohexyl acrylate (TMCHA).

[0012] The photoinitiator is preferably at least one of 2-methyl-1-(4-methylmercaptophenyl)-2-morpholino-1-propanone (907), ethyl 2,4,6-trimethylbenzoylphenylphosphonate (TPO), α,α-dimethoxybenzoyl ketal (651 or 1065), and 1-hydroxycyclobenzophenone (184).

[0013] The A component is an isocyanate compound, preferably an aliphatic isocyanate, and the isocyanate compound accounts for 11.01% to 13.07% of the mass percentage of the ultra-tough UV-curable nano-reinforced aliphatic polyurea coating raw material.

[0014] The aliphatic isocyanate is preferably one or more of hexamethylene diisocyanate (HDI), isoflurane diisocyanate (IPDI), dicyclohexylmethane-4,4'-diisocyanate (HMDI), phenyldimethyl diisocyanate (XDI), and tetramethyl isophenyldimethyl diisocyanate (TMXDI).

[0015] Component B consists of polyetheramine and amine chain extender.

[0016] Among them, the polyetheramine is selected from one or more of D2000, CGA-D230, CGA-D2000, T5000, CGA-T403, and CGA-T5000, accounting for 31.03% to 37.85% of the mass percentage of the ultra-tough UV-curable nano-reinforced aliphatic polyurea coating raw material.

[0017] The amine chain extender is selected from one or more of 3,3'-dichloro-4,4'-diaminodiphenylmethane (MOCA), diethyltoluene diamine (E-100), and isophorone diamine (IPDA), accounting for 5.16% to 6.19% of the mass percentage of the ultra-tough UV-curable nano-reinforced aliphatic polyurea coating raw material.

[0018] The present invention discloses a method for preparing an ultra-tough UV-curable nano-reinforced aliphatic polyurea coating, comprising the following steps:

[0019] Step (1): Mix the dehydrated polyetheramine and aliphatic isocyanate evenly, prepolymerize, then add solvent and stir to obtain solution A;

[0020] Step (2): Mix solution A with an amine chain extender until solution B is obtained;

[0021] Step (3): Under conditions of no light, solution B and acrylic monomer are mixed evenly to obtain acrylate-aliphatic polyurea resin.

[0022] Step (4): Under light-free conditions, the acrylate-aliphatic polyurea resin and the photoinitiator are mixed evenly to obtain an acrylate-aliphatic polyurea resin mixture that can be cured by ultraviolet light.

[0023] Step (5): Mix the acrylate-aliphatic polyurea resin mixture with graphene nanosheets (GNPs) and stir until homogeneous to obtain an ultra-tough UV-curable nano-reinforced aliphatic polyurea coating that can be cured by UV light.

[0024] The ultra-tough UV-curable nano-reinforced aliphatic polyurea elastomer of the present invention uses an ultra-tough UV-curable nano-reinforced aliphatic polyurea coating as a raw material, and is cured by UV light to obtain an ultra-tough UV-curable nano-reinforced aliphatic polyurea elastomer.

[0025] The specific preparation method is as follows: Ultra-tough UV-cured nano-reinforced aliphatic polyurea coating is poured into a 3D printing device for printing, achieving a strength of 5–30 mW / cm². 2 After polymerization is initiated under 405nm ultraviolet light and then cured, an ultra-tough ultraviolet light-cured nano-reinforced aliphatic polyurea elastomer is obtained.

[0026] In step (1), the dehydration process is as follows: dehydration at 100-125℃ and under a vacuum of -0.7MPa for 1.5-2 hours;

[0027] In step (1), the prepolymer is stirred in a reactor at 75-100°C for 0.8-1.5 hours at a stirring speed of 800-1000 r / min, with an inert gas protection to reduce side reactions.

[0028] In step (1), the solvent is one of dimethylformamide (DMF) and dimethylacetamide (DMAc), accounting for 27.52% to 37.85% of the mass percentage of the ultra-tough UV-curable nano-reinforced aliphatic polyurea coating raw material.

[0029] In step (2), the mixture is stirred uniformly at room temperature using mechanical stirring at a speed of 800 r / min to 1000 r / min. During the stirring process, the stirring system is protected by nitrogen gas to reduce the occurrence of side reactions. The mixing time is preferably 5 to 10 minutes.

[0030] In step (3), the reaction is stirred at a temperature of 40-60°C for 0.5-1h at a stirring speed of 800r / min-1000r / min.

[0031] In step (4), the mixture is stirred evenly at room temperature for 1 to 1.5 hours using mechanical stirring at a speed of 800 r / min to 1000 r / min.

[0032] In step (5), graphene nanosheets (GNPs) are prepared by the following method: 1g of graphite sheet and 500mL of ethanol (EtOH) are placed in a high-speed mixer, and the mixture is mechanically treated at a speed of 28000rpm for 5, 15, 25 and 35 minutes. Then, the mixture is filtered and dried to obtain few-layer graphene nanosheets.

[0033] Graphite flakes were added to an ethanol solution and mechanically treated at 28,000–30,000 rpm for 5–35 min, then filtered and dried to obtain graphene nanosheets; wherein, the solid-liquid ratio was 1–2 g of graphite flakes to 500–1000 mL of ethanol.

[0034] The graphene nanosheets mentioned are few-layer graphene nanosheets.

[0035] In step (5), the reaction is mechanically stirred for 1 hour at room temperature at a stirring speed of 800 r / min to 1000 r / min.

[0036] An ultra-tough UV-curable nano-reinforced aliphatic polyurea elastomer was prepared using the above-described method.

[0037] The aforementioned ultra-tough UV-cured nano-reinforced aliphatic polyurea elastomer exhibits a tensile strength of 10.09–18.27 MPa, an elongation at break of 142.89–213.78%, a Young's modulus of 46.24–82.65 MPa, and an impact strength of 434.56–496.22 KJ / m. 2 .

[0038] The application of the ultra-tough UV-cured nano-reinforced aliphatic polyurea elastomer in aerospace coatings.

[0039] The ultra-tough UV-curable nano-reinforced aliphatic polyurea coating, its elastomer, preparation method, and application of the present invention have the following advantages compared to existing aliphatic polyurea elastomers:

[0040] 1. By doping graphene nanosheets, the mechanical properties of UV-cured polyurea elastomers are improved. This is because graphene itself has excellent rigidity. When it is dispersed in the polyurea matrix and forms a good interfacial interaction with the polyurea matrix, it can increase the tensile strength of the matrix.

[0041] 2. Compared to other methods of preparing aliphatic polyurea elastomers, the photocurable aliphatic polyurea elastomer of this invention cures much faster. When exposed to a light source of a specific wavelength, such as ultraviolet light, this material can undergo a polymerization reaction instantly and rapidly transform into a solid state; the reaction process is extremely rapid. This provides the manufacturing industry with a method to quickly transform materials from a liquid to a solid state, thereby reducing production cycle time and improving production efficiency.

[0042] 3. By changing the type and proportion of acrylic monomers, the molecular structure of the photocurable polyurea elastomer can be adjusted, thereby altering the curing speed and shrinkage rate of the raw materials and changing the mechanical properties of the polyurea elastomer. Compared to traditional aliphatic polyurea elastomers, UV-cured aliphatic polyurea elastomers significantly improve the tensile, fracture, and impact resistance properties. Furthermore, the addition of graphene, despite its inherent color, does not reduce performance. Instead, the active sites formed by graphene's π-electron structure possess strong electrophilicity, capturing and reacting with free radicals. This helps prevent adverse reactions and impurity formation, effectively improving the performance of the photocuring system and further enhancing the overall performance of the prepared elastomer. Attached Figure Description

[0043] Figure 1 The stress-strain curves of Comparative Examples 1 to 7 of this invention are shown below.

[0044] Figure 2The results of tensile property tests in Examples 1 to 6 of this invention are based on the addition of different contents of GNPs. Detailed Implementation

[0045] The present invention will be further described in detail below with reference to the embodiments.

[0046] The mechanical properties of the prepared UV-cured aliphatic polyurea elastomer and the ultra-tough UV-cured nano-reinforced aliphatic polyurea elastomer were tested in the following examples:

[0047] According to the testing requirements for tensile properties of elastomeric materials in the national standard GB / T 528-2009, a type II dumbbell tensile specimen meeting the requirements was prepared. The total length of the tensile specimen was 10 mm, the width was 2 mm, the gauge length was 10.0 ± 0.5 mm, and the specimen thickness was 1.0 ± 0.2 mm. All tensile tests were conducted at room temperature at a tensile rate of 50 mm / min.

[0048] The impact protection performance of the prepared ultra-tough UV-cured aliphatic polyurea elastomer and ultra-tough UV-cured nano-reinforced aliphatic polyurea elastomer were tested in the following examples:

[0049] The impact resistance of polyurea-aluminum sheet composite structures was tested on a simply supported beam impact testing machine according to ISO 179-1:2000. Using aluminum sheets with custom dimensions of 100mm x 12.5mm x 2mm (length x width x thickness), polyurea film was cut into strips of the same dimensions and adhered to the aluminum sheets using epoxy adhesive. The impact resistance test was conducted at room temperature. The testing machine used a pendulum hammer with an impact energy of 15J and an impact velocity of 3.8m / s. The aluminum alloy used was 6061 aluminum alloy.

[0050] Comparative Example 1

[0051] A method for preparing an ultra-tough UV-curable aliphatic polyurea elastomer includes the following steps:

[0052] (1) Mix 12g D2000 and 3.15g HDI that have been dehydrated at 110℃ and -0.7MPa vacuum for 1.5h evenly for prepolymerization, then add 13g dimethylacetamide and stir and dilute at a speed of 800r / min to 1000r / min to obtain solution A;

[0053] (2) Mix solution A with 8g of isophorone diamine at room temperature at a speed of 800r / min to 1000r / min for 5 minutes to obtain solution B;

[0054] (3) Under no light conditions, solution B was mixed with 1.3g of EA and 0g of HEMA (molar ratio of 10:0) at 50°C and stirred at a speed of 800r / min to 1000r / min for 40min to obtain acrylate-polyurea resin.

[0055] (4) Under light-free conditions, polyurea resin and 1.88 g of photoinitiator TPO were stirred at room temperature at a speed of 800 r / min to 1000 r / min for 1 h. The resulting acrylate-polyurea resin was then poured into a 3D printing device for printing, achieving a strength of 5 mW / cm². 2 After polymerization is initiated under 405nm ultraviolet light, curing is performed to obtain the final ultraviolet-cured aliphatic polyurea elastomer.

[0056] (5) UV-cured aliphatic polyurea elastomer was made into specimens and subjected to tensile and impact resistance tests.

[0057] Comparative Example 2

[0058] A method for preparing an ultra-tough UV-curable aliphatic polyurea elastomer includes the following steps:

[0059] (1) Mix 12g D2000 and 3.15g HDI that have been dehydrated at 110℃ and -0.7MPa vacuum for 1.5h evenly for prepolymerization, then add 13g dimethylacetamide and stir and dilute at a speed of 800r / min to 1000r / min to obtain solution A;

[0060] (2) Mix solution A with 8g of isophorone diamine at room temperature at a speed of 800r / min to 1000r / min for 5 minutes to obtain solution B;

[0061] (3) Under no light conditions, solution B was mixed with 0.792 g of EA and 0.13 g of HEMA (molar ratio 9:1) at 50°C and stirred at 800 r / min to 1000 r / min for 40 min to obtain acrylate-polyurea resin.

[0062] (4) Under light-free conditions, polyurea resin and 1.88 g of photoinitiator TPO were stirred at room temperature at a speed of 800 r / min to 1000 r / min for 1 h. The resulting acrylate-polyurea resin was then poured into a 3D printing device for printing, achieving a strength of 5 mW / cm². 2 After polymerization is initiated under 405nm ultraviolet light, curing is performed to obtain the final ultraviolet-cured aliphatic polyurea elastomer.

[0063] (5) UV-cured aliphatic polyurea elastomer was made into specimens and subjected to tensile and impact resistance tests.

[0064] Comparative Example 3

[0065] A method for preparing an ultra-tough UV-curable aliphatic polyurea elastomer includes the following steps:

[0066] (1) Mix 12g D2000 and 3.15g HDI that have been dehydrated at 110℃ and -0.7MPa vacuum for 1.5h evenly for prepolymerization, then add 13g dimethylacetamide and stir and dilute at a speed of 800r / min to 1000r / min to obtain solution A;

[0067] (2) Mix solution A with 8g of isophorone diamine at room temperature at a speed of 800r / min to 1000r / min for 5 minutes to obtain solution B;

[0068] (3) Under no light conditions, solution B was mixed with 0.616 g of EA and 0.39 g of HEMA (molar ratio of 7:3) at 50°C and stirred at 800 r / min to 1000 r / min for 40 min to obtain acrylate-polyurea resin.

[0069] (4) Under light-free conditions, polyurea resin and 1.88 g of photoinitiator TPO were stirred at room temperature at a speed of 800 r / min to 1000 r / min for 1 h. The resulting acrylate-polyurea resin was then poured into a 3D printing device for printing, achieving a strength of 5 mW / cm². 2 After polymerization is initiated under 405nm ultraviolet light, curing is performed to obtain the final ultraviolet-cured aliphatic polyurea elastomer.

[0070] (5) UV-cured aliphatic polyurea elastomer was made into specimens and subjected to tensile and impact resistance tests.

[0071] Comparative Example 4

[0072] A method for preparing an ultra-tough UV-curable aliphatic polyurea elastomer includes the following steps:

[0073] (1) Mix 12g D2000 and 3.15g HDI that have been dehydrated at 110℃ and -0.7MPa vacuum for 1.5h evenly for prepolymerization, then add 13g dimethylacetamide and stir and dilute at a speed of 800r / min to 1000r / min to obtain solution A;

[0074] (2) Mix solution A with 8g of isophorone diamine at room temperature at a speed of 800r / min to 1000r / min for 5 minutes to obtain solution B;

[0075] (3) Under no light conditions, solution B was mixed with 0.44 g of EA and 0.65 g of HEMA (molar ratio of 5:5) at 50°C and stirred at a speed of 800 r / min to 1000 r / min for 40 min to obtain acrylate-polyurea resin.

[0076] (4) Under light-free conditions, polyurea resin and 1.88 g of photoinitiator TPO were stirred at room temperature at a speed of 800 r / min to 1000 r / min for 1 h. The resulting acrylate-polyurea resin was then poured into a 3D printing device for printing, achieving a strength of 5 mW / cm². 2 After polymerization is initiated under 405nm ultraviolet light, curing is performed to obtain the final ultraviolet-cured aliphatic polyurea elastomer.

[0077] (5) UV-cured aliphatic polyurea elastomer was made into specimens and subjected to tensile and impact resistance tests.

[0078] Comparative Example 5

[0079] A method for preparing an ultra-tough UV-curable aliphatic polyurea elastomer includes the following steps:

[0080] (1) Mix 12g D2000 and 3.15g HDI that have been dehydrated at 110℃ and -0.7MPa vacuum for 1.5h evenly for prepolymerization, then add 13g dimethylacetamide and stir and dilute at a speed of 800r / min to 1000r / min to obtain solution A;

[0081] (2) Mix solution A with 8g of isophorone diamine at room temperature at a speed of 800r / min to 1000r / min for 5 minutes to obtain solution B;

[0082] (3) Under no light conditions, solution B was mixed with 0.264 g of EA and 0.91 g of HEMA (molar ratio of 3:7) at 50°C and stirred at 800 r / min to 1000 r / min for 40 min to obtain acrylate-polyurea resin.

[0083] (4) Under light-free conditions, polyurea resin and 1.88 g of photoinitiator TPO were stirred at 800 r / min to 1000 r / min for 1 h at room temperature. The resulting acrylate-polyurea resin body was then poured into a 3D printing device for printing, achieving a strength of 5 mW / cm². 2 After polymerization is initiated under 405nm ultraviolet light, curing is performed to obtain the final ultraviolet-cured aliphatic polyurea elastomer.

[0084] (5) UV-cured aliphatic polyurea elastomer was made into specimens and subjected to tensile and impact resistance tests.

[0085] Comparative Example 6

[0086] A method for preparing an ultra-tough UV-curable aliphatic polyurea elastomer includes the following steps:

[0087] (1) Mix 12g D2000 and 3.15g HDI that have been dehydrated at 110℃ and -0.7MPa vacuum for 1.5h evenly for prepolymerization, then add 13g dimethylacetamide and stir and dilute at a speed of 800r / min to 1000r / min to obtain solution A;

[0088] (2) Mix solution A with 8g of isophorone diamine at room temperature at a speed of 800r / min to 1000r / min for 5 minutes to obtain solution B;

[0089] (3) Under no light conditions, solution B was mixed with 0.088 g of EA and 1.17 g of HEMA (molar ratio of 1:9) at 50°C and stirred at 800 r / min to 1000 r / min for 40 min to obtain acrylate-polyurea resin.

[0090] (4) Under light-free conditions, polyurea resin and 1.88 g of photoinitiator TPO were stirred at 800 r / min to 1000 r / min for 1 h at room temperature. The resulting acrylate-polyurea resin body was then poured into a 3D printing device for printing, achieving a strength of 5 mW / cm². 2 After polymerization is initiated under 405nm ultraviolet light, curing is performed to obtain the final ultraviolet-cured aliphatic polyurea elastomer.

[0091] (5) UV-cured aliphatic polyurea elastomer was made into specimens and subjected to tensile and impact resistance tests.

[0092] Comparative Example 7

[0093] A method for preparing an ultra-tough UV-curable aliphatic polyurea elastomer includes the following steps:

[0094] (1) Mix 12g D2000 and 3.15g HDI that have been dehydrated at 110℃ and -0.7MPa vacuum for 1.5h evenly for prepolymerization, then add 13g dimethylacetamide and stir and dilute at a speed of 800r / min to 1000r / min to obtain solution A;

[0095] (2) Mix solution A with 8g of isophorone diamine at room temperature at a speed of 800r / min to 1000r / min for 5 minutes to obtain solution B;

[0096] (3) Under no light conditions, solution B was mixed with 0g of EA and 1.3g of HEMA (molar ratio of 0:10) at 50°C and stirred at 800r / min to 1000r / min for 40min to obtain acrylate-polyurea resin.

[0097] (4) Under light-free conditions, polyurea resin and 1.88 g of photoinitiator TPO were stirred at 800 r / min to 1000 r / min for 1 h at room temperature. The resulting acrylate-polyurea elastomer was then poured into a 3D printing device for printing, achieving a strength of 5 mW / cm². 2 After polymerization is initiated under 405nm ultraviolet light, curing is performed to obtain the final ultraviolet-cured aliphatic polyurea elastomer.

[0098] (5) UV-cured aliphatic polyurea elastomer was made into specimens and subjected to tensile and impact resistance tests.

[0099] Example 1:

[0100] A method for preparing an ultra-tough UV-curable nano-reinforced aliphatic polyurea elastomer, based on Comparative Example 5, includes the following steps:

[0101] (1) A molar ratio of EA to HEMA of 3:7 was selected. After uniformly mixing with the photoinitiator TPO, 0.1 wt% graphene nanosheets (GNPs) were added and stirred. The resulting ultra-tough UV-curable nano-reinforced aliphatic polyurea coating was poured into a 3D printing device for printing, with a strength of 5 mW / cm. 2 After polymerization is initiated under 405nm ultraviolet light and then cured, the final ultra-tough ultraviolet light-cured nano-reinforced aliphatic polyurea elastomer is obtained.

[0102] (2) The ultra-tough UV-cured nano-reinforced aliphatic polyurea elastomer was made into specimens and subjected to a series of tensile and impact resistance tests.

[0103] Example 2:

[0104] A method for preparing an ultra-tough UV-cured nano-reinforced aliphatic polyurea elastomer, similar to Example 1, but differing in the following steps:

[0105] (1) A molar ratio of EA to HEMA of 3:7 was selected. After uniformly mixing with the photoinitiator TPO, 0.2 wt% graphene nanosheets (GNPs) were added and stirred. The resulting ultra-tough UV-curable nano-reinforced aliphatic polyurea coating was poured into a 3D printing device for printing, with a strength of 5 mW / cm. 2After polymerization is initiated under 405nm ultraviolet light and then cured, the final ultra-tough ultraviolet light-cured nano-reinforced aliphatic polyurea elastomer is obtained.

[0106] (2) The ultra-tough UV-cured nano-reinforced aliphatic polyurea elastomer was made into specimens and subjected to tensile and impact resistance tests.

[0107] Example 3

[0108] A method for preparing an ultra-tough UV-cured nano-reinforced aliphatic polyurea elastomer, similar to Example 1, but differing in the following steps:

[0109] (1) A molar ratio of EA to HEMA of 3:7 was selected. After uniformly mixing with the photoinitiator TPO, 0.3 wt% graphene nanosheets (GNPs) were added and stirred. The resulting ultra-tough UV-curable nano-reinforced aliphatic polyurea coating was poured into a 3D printing device for printing, with a strength of 5 mW / cm. 2 After polymerization is initiated under 405nm ultraviolet light and then cured, the final ultra-tough ultraviolet light-cured nano-reinforced aliphatic polyurea elastomer is obtained.

[0110] (2) The ultra-tough UV-cured nano-reinforced aliphatic polyurea elastomer was made into specimens and subjected to a series of tensile and impact resistance tests.

[0111] Example 4:

[0112] A method for preparing an ultra-tough UV-cured nano-reinforced aliphatic polyurea elastomer, similar to Example 1, but differing in the following steps:

[0113] (1) A molar ratio of EA to HEMA of 3:7 was selected. After uniformly mixing with the photoinitiator TPO, 0.4 wt% graphene nanosheets (GNPs) were added and stirred. The resulting ultra-tough UV-curable nano-reinforced aliphatic polyurea coating was poured into a 3D printing device for printing, with a strength of 5 mW / cm. 2 After polymerization is initiated under 405nm ultraviolet light and then cured, the final ultra-tough ultraviolet light-cured nano-reinforced aliphatic polyurea elastomer is obtained.

[0114] (2) The ultra-tough UV-cured nano-reinforced aliphatic polyurea elastomer was made into specimens and subjected to tensile and impact resistance tests.

[0115] Example 5:

[0116] A method for preparing an ultra-tough UV-cured nano-reinforced aliphatic polyurea elastomer, similar to Example 1, but differing in the following steps:

[0117] (1) A molar ratio of EA to HEMA of 3:7 was selected. After uniformly mixing with the photoinitiator TPO, 0.5 wt% graphene nanosheets (GNPs) were added and stirred. The resulting ultra-tough UV-curable nano-reinforced aliphatic polyurea coating was poured into a 3D printing device for printing, with a strength of 5 mW / cm. 2 After polymerization is initiated under 405nm ultraviolet light and then cured, the final ultra-tough ultraviolet light-cured nano-reinforced aliphatic polyurea elastomer is obtained.

[0118] (2) The ultra-tough UV-cured nano-reinforced aliphatic polyurea elastomer was made into specimens and subjected to tensile and impact resistance tests.

[0119] Table 1. Mechanical properties and impact strength of ultra-tough UV-cured aliphatic polyurea elastomers with different ratios of EA and TBEMA

[0120]

[0121] Performance testing of an ultra-tough UV-cured aliphatic polyurea elastomer:

[0122] Test Example 1:

[0123] Mechanical property testing of an ultra-tough UV-cured aliphatic polyurea elastomer includes the following steps:

[0124] The UV-cured aliphatic polyurea elastomer materials obtained in Comparative Examples 1-7 were cut into standard tensile specimens, and tensile tests were conducted using a computer-controlled servo tensile testing machine. The experimental data were recorded, and the changes in the tensile properties of the materials were analyzed.

[0125] As shown in the table, the tensile strength and Young's modulus of the UV-cured aliphatic polyurea elastomer material increase with the increase of HEMA addition. The tensile strength and Young's modulus reach their maximum when EA and HEMA are added in a 0:10 ratio, reaching 11.93 MPa and 48.08 MPa respectively, representing increases of 271.65% and 349.34%. The elongation at break of the UV-cured aliphatic polyurea elastomer material initially increases and then decreases with increasing HEMA addition, reaching its maximum at a 5:5 ratio of EA and HEMA, reaching 299.41%. This is because the presence of HEMA forms denser hard segments, improving the overall rigidity of the material and reducing the elongation at break. To more intuitively observe the changes in mechanical properties under different ratios, it is evident that... Figure 1 .

[0126] Data analysis shows that when the molar ratio of EA to HEMA is between 5:5 and 3:7, the UV-cured aliphatic polyurea elastomer exhibits the best overall mechanical properties, namely, an increase in tensile strength of 111.21%–144.25%, an increase in Young's modulus of 223.36%–277.86%, and a decrease in elongation at break of only 12.98%–25.68%.

[0127] Test Example 2:

[0128] Mechanical property testing of an ultra-tough UV-cured aliphatic polyurea elastomer includes the following steps:

[0129] The UV-cured aliphatic polyurea elastomer materials obtained in Comparative Examples 1-7 were subjected to impact resistance tests using a simply supported beam impact testing machine. The table above shows that when the molar ratio of EA to HEMA is 10:0, the impact strength of the UV-cured aliphatic polyurea elastomer is 371.5 kJ / m². 2 Compared to aluminum sheets, the impact resistance was improved by 6.14%; when the molar ratio of EA to HEMA was 9:1, the impact strength of the UV-cured aliphatic polyurea elastomer was 377.34 kJ / m². 2 Compared to aluminum sheets, the impact resistance was improved by 7.81%; when the molar ratio of EA to TBEMA was 7:3, the impact strength of the UV-cured aliphatic polyurea elastomer was 388.22 kJ / m². 2 Compared to aluminum sheets, the impact resistance was improved by 10.92%; when the molar ratio of EA to HEMA was 5:5, the impact strength of the UV-cured aliphatic polyurea elastomer was 397.99 kJ / m². 2 Compared to aluminum sheets, the impact resistance was improved by 13.71%; when the molar ratio of EA to HEMA was 3:7, the impact strength of the UV-cured aliphatic polyurea elastomer was 419.97 kJ / m². 2 Compared to aluminum sheets, the impact resistance was improved by 20.01%; when the molar ratio of EA to HEMA was 1:9, the impact strength of the UV-cured aliphatic polyurea elastomer was 421.24 kJ / m². 2 The tensile strength was increased by 20.35% compared to aluminum sheets; this indicates that when the molar ratio of EA to HEMA is 0:10, the impact strength of the UV-cured aliphatic polyurea elastomer is 434.06 kJ / m². 2 Compared to aluminum sheets, its impact resistance is improved by 24.01%.

[0130] Performance tests on UV-cured aliphatic polyurea elastomers revealed that the optimal overall performance was achieved when the EA to THEMA molar ratio was between 5:5 and 3:7. Specifically, the tensile strength increased by 111.21%–144.25%, the Young's modulus increased by 223.36%–277.86%, the elongation at break decreased by only 12.98%–25.68%, and the impact strength reached 397.99 kJ / m². 2 ~419.97kJ / m 2 Compared to aluminum sheets, the impact resistance is improved by 13.71% to 20.01%.

[0131] A 3:7 molar ratio of EA to HEMA was selected. After uniformly mixing with the photoinitiator TPO, 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, and 0.5wt% of graphene nanosheets were added respectively (Examples 8-12) to prepare ultra-tough UV-cured nano-reinforced aliphatic polyurea elastomers with different proportions. Subsequently, they were made into specimens and subjected to a series of tensile and impact resistance tests. The experimental procedures were the same as those in tests 1 and 2.

[0132] Table 2. Mechanical properties and impact strength of ultra-tough UV-cured nano-reinforced aliphatic polyurea elastomers with different graphene contents

[0133]

[0134] The data in Table 2 clearly show that the addition of GNPs significantly increases the tensile strength, Young's modulus, and impact strength of polyurea elastomers. According to... Figure 2 It is evident that the ultra-tough UV-cured nano-reinforced aliphatic polyurea elastomer exhibits the best mechanical properties when the graphene content is 0.2 wt%. Its tensile strength and elongation at break reach 18.77 MPa and 196.33%, respectively. Compared with pure polyurea elastomer, the tensile strength is increased by 139.41%, but the elongation at break decreases by 25.46%. This is mainly due to stress concentration caused by filler aggregation; the aggregation of GNPs hinders the movement of polyurea molecular chains and inhibits the orientation of chain segments.

[0135] Simultaneously, the impact strength increases with the increase of GNP content. When the content is 0.2 wt%, the impact strength is 451.79 KJ / m. 2 Compared with pure polyurea elastomer, it improved by 7.58%.

[0136] In conclusion, the ultra-tough UV-cured nano-reinforced aliphatic polyurea elastomer exhibits the best overall performance when the GNP content is 0.2 wt%.

[0137] Comparative Example 8

[0138] Because graphene is a two-dimensional carbon material with its π-electron cloud distributed in a plane, π-π interactions occur, forming π-π stacking. If graphene is directly added to solution A, the π-π stacking of graphene will affect the mobility of the molecular chains, thus impacting the final properties after chain extension.

[0139] Good light transmittance is a key element in the photocuring process. Normally functional fillers, due to their color, can affect the light transmittance of coatings, thus impacting the properties of elastomers. However, graphene, a two-dimensional crystal structure with a single layer of carbon atoms arranged in a hexagonal pattern, possesses extremely high strength. Under impact or strain, graphene's bending and deformation properties help prevent material breakage during external impact or deformation. It can also absorb some energy, slowing the propagation of impact, thereby reducing stress concentration and improving the material's toughness.

Claims

1. A super-tough UV-curable nano-reinforced aliphatic polyurea coating, characterized in that, The raw materials of this ultra-tough UV-curable nano-reinforced aliphatic polyurea coating include component A and component B, as well as acrylic monomers, photoinitiators, and graphene nanosheets. Among them, the acrylic monomers account for 5.84% to 6.89% of the mass percentage of the raw materials of the ultra-tough UV-curable nano-reinforced aliphatic polyurea coating; the acrylic monomers are a mixture of ethyl acrylate and hydroxyethyl methacrylate, with a molar ratio of ethyl acrylate:hydroxyethyl methacrylate = 3:

7. The A component is an isocyanate compound, and the isocyanate compound accounts for 11.01% to 13.07% of the mass percentage of the ultra-tough UV-curable nano-reinforced aliphatic polyurea coating raw material. The isocyanate compound mentioned above is specifically one or more of hexamethylene diisocyanate, isoflurone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, phenyldimethyl diisocyanate, and tetramethyl isophenyldimethyl diisocyanate. Component B is a polyetheramine and an amine chain extender; Among them, the polyetheramine is selected from one or more of D2000, CGA-D230, CGA-D2000, T5000, CGA-T403, and CGA-T5000, accounting for 31.03% to 37.85% of the mass percentage of the ultra-tough UV-curable nano-reinforced aliphatic polyurea coating raw material; The amine chain extender is selected from one or more of 3,3'-dichloro-4,4'-diaminodiphenylmethane, diethyltoluenediamine, and isophoronediamine, accounting for 5.16% to 6.19% of the mass percentage of the ultra-tough UV-curable nano-reinforced aliphatic polyurea coating raw material; The photoinitiator accounts for 6.19% to 7.91% of the mass percentage of the ultra-tough UV-curable nano-reinforced aliphatic polyurea coating raw material; the graphene nanosheets account for 0.1% to 0.5% of the mass percentage of the ultra-tough UV-curable nano-reinforced aliphatic polyurea coating raw material. The ultra-tough UV-curable nano-reinforced aliphatic polyurea coating is prepared using the following method: Step (1): Mix the dehydrated polyetheramine and isocyanate compound evenly, perform prepolymerization, and then add solvent and stir to obtain solution A; Step (2): Mix solution A with an amine chain extender until solution B is obtained; Step (3): Under light-free conditions, solution B is mixed with acrylic monomer to obtain acrylate-aliphatic polyurea resin. Step (4): Under light-free conditions, the acrylate-aliphatic polyurea resin and the photoinitiator are mixed evenly to obtain an acrylate-aliphatic polyurea resin mixture that can be cured by ultraviolet light. Step (5): Mix the acrylate-aliphatic polyurea resin mixture with graphene nanosheets and stir evenly to obtain an ultra-tough UV-curable nano-reinforced aliphatic polyurea coating that can be cured by ultraviolet light.

2. The ultra-tough UV-curable nano-reinforced aliphatic polyurea coating according to claim 1, characterized in that, The photoinitiator is at least one of 2-methyl-1-(4-methylmercaptophenyl)-2-morpholino-1-propanone, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, α,α-dimethoxybenzoylazone, and 1-hydroxycyclobenzophenone.

3. The method for preparing the ultra-tough UV-curable nano-reinforced aliphatic polyurea coating according to claim 1 or 2, characterized in that, Includes the following steps: Step (1): Mix the dehydrated polyetheramine and isocyanate compound evenly, perform prepolymerization, and then add solvent and stir to obtain solution A; Step (2): Mix solution A with an amine chain extender until solution B is obtained; Step (3): Under light-free conditions, solution B is mixed with acrylic monomer to obtain acrylate-aliphatic polyurea resin. Step (4): Under light-free conditions, the acrylate-aliphatic polyurea resin and the photoinitiator are mixed evenly to obtain an acrylate-aliphatic polyurea resin mixture that can be cured by ultraviolet light. Step (5): Mix the acrylate-aliphatic polyurea resin mixture with graphene nanosheets and stir evenly to obtain an ultra-tough UV-curable nano-reinforced aliphatic polyurea coating that can be cured by ultraviolet light.

4. The method for preparing the ultra-tough UV-curable nano-reinforced aliphatic polyurea coating according to claim 3, characterized in that, In step (1), the dehydration process is as follows: dehydration at 100-125℃ and under a vacuum of -0.7MPa for 1.5-2 hours; And / or, the prepolymer is stirred in a reactor at 75–100°C for 0.8–1.5 h at a stirring speed of 800–1000 r / min under inert gas protection; And / or, in step (2), the stirring speed for uniform mixing is 800 r / min to 1000 r / min, and the time for uniform mixing is 5 to 10 min; And / or, in step (3), the reaction is stirred at a temperature of 40 to 60°C for 0.5 to 1 hour at a stirring speed of 800 r / min to 1000 r / min; And / or, in step (4), the mixture is uniformly mixed by mechanical stirring at room temperature for 1 to 1.5 hours at a stirring speed of 800 r / min to 1000 r / min. And / or, in step (5), the reaction is mechanically stirred for 1 hour at room temperature at a stirring speed of 800 r / min to 1000 r / min.

5. A super-tough UV-curable nano-reinforced aliphatic polyurea elastomer, characterized in that, Using the ultra-tough UV-curable nano-reinforced aliphatic polyurea coating as described in claim 1 or 2 as raw material, ultraviolet light-induced curing is used to obtain an ultra-tough UV-curable nano-reinforced aliphatic polyurea elastomer.

6. The method for preparing the ultra-tough UV-cured nano-reinforced aliphatic polyurea elastomer according to claim 5, characterized in that, The ultra-tough UV-curable nano-reinforced aliphatic polyurea coating as described in claim 1 or 2 is poured into a 3D printing device for printing, achieving a strength of 5–30 mW / cm². 2 After polymerization is initiated under 405nm ultraviolet light and then cured, an ultra-tough ultraviolet light-cured nano-reinforced aliphatic polyurea elastomer is obtained.

7. A super-tough UV-cured nano-reinforced aliphatic polyurea elastomer, characterized in that, The ultra-tough UV-cured nano-reinforced aliphatic polyurea elastomer, prepared by the method described in claim 6, exhibits a tensile strength of 10.09–18.27 MPa, an elongation at break of 142.89–213.78%, a Young's modulus of 46.24–82.65 MPa, and an impact strength of 434.56–496.22 KJ / m². 2 .

8. The application of the ultra-tough UV-cured nano-reinforced aliphatic polyurea elastomer as described in claim 5 or 7 in aerospace coatings.

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