Repairable polyurea elastomer and preparation method thereof
By introducing dynamic reversible disulfide bonds and optimizing the combination of chain extenders, a high-strength, self-healing polyurea elastomer is formed, which solves the problem of poor repair performance of traditional polyurethane elastomers, achieves a balance between high strength and self-healing ability, and improves the corrosion resistance and water resistance of the material.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-13
- Publication Date
- 2026-04-07
AI Technical Summary
Traditional polyurethane elastomers have strong mechanical properties but poor dynamic reconstruction ability due to their irreversible cross-linked network structure, resulting in poor repair performance and difficulty in effectively self-healing in high-intensity application scenarios.
A high-strength, repairable polyurea elastomer is formed by using solvents N,N-dimethylacetamide, polytetramethylene ether glycol, diphenylmethane diisocyanate, catalysts dibutyltin dilaurate, cystamine dihydrochloride, and polyimide DMAc solution, through dynamic reversible disulfide bonds and an optimized combination of chain extenders.
While maintaining high strength, the self-healing ability of the material is significantly improved. By introducing dynamic reversible disulfide bonds and optimizing the microphase separation nanostructure, the elastic modulus and service stability of the material are improved, and the corrosion resistance and water resistance are enhanced.
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Abstract
Description
Technical Field
[0001] This invention relates to a polyurea elastomer and its preparation method, belonging to the field of polyurea elastomer technology. Background Technology
[0002] Polyurea elastomers are high-performance synthetic polymeric elastomer materials obtained by polymerizing isocyanate components with amino compounds (or amino-terminated polyethers). Compared with the urethane bonds in polyurethane, the urea bonds in the polyurea molecular chain have higher polarity, enabling the formation of denser and stronger intermolecular hydrogen bonds, which endows the material with excellent mechanical properties and temperature resistance. Currently, polyurea elastomers are widely used in high-speed rail waterproofing, industrial corrosion protection, and military applications such as blast and fragmentation protection. However, existing polyurea elastomers have some insurmountable limitations, the most prominent of which is the difficulty in simultaneously achieving mechanical strength and repairability.
[0003] Traditional polyurethane elastomers typically employ irreversible cross-linked network structures. While this structure enhances the material's mechanical properties, it also limits its dynamic reconstruction ability, resulting in poor self-healing performance. Particularly in high-strength applications, polyurethane elastomers are prone to failure due to mechanical damage, and their inability to spontaneously repair themselves limits their lifespan and increases maintenance costs. In recent years, researchers have begun to explore improving the self-healing properties of polyurethane elastomers by introducing dynamically reversible chemical bonds (such as hydrogen bonds, metal coordination bonds, and disulfide bonds). Among these, disulfide bonds have attracted increasing attention due to their ability to break and reform under specific conditions. Polyurethane elastomers containing disulfide bonds can achieve dynamic reconstruction under the influence of heat, light, or chemical reducing agents, thus endowing the material with excellent self-healing properties. However, research on these materials still faces many challenges, such as how to maintain high strength and good processability while improving self-healing performance.
[0004] Therefore, developing a polyurethane elastomer that combines high strength and self-healing capabilities, while systematically investigating the effects of solvents and chain extenders on material properties, is of significant scientific importance and practical value. Such materials can not only extend product lifespan and reduce maintenance and replacement costs, but also reduce industrial waste generation, aligning with the principles of sustainable development. Summary of the Invention
[0005] This invention addresses the problem that traditional polyurethane elastomers typically employ irreversible cross-linked network structures. While this structure enhances the mechanical properties of the material, it also limits its dynamic reconstruction ability, resulting in poor repair performance. Therefore, this invention proposes a repairable polyurea elastomer and its preparation method.
[0006] The technical solution adopted by the present invention to solve the above problems is as follows: The repairable polyurea elastomer of the present invention comprises a solvent, polytetramethylene ether glycol, diphenylmethane diisocyanate, a catalyst, cystamine dihydrochloride, and a polyimide DMAc solution, wherein the mass fractions of each component are as follows: solvent 200 parts, polytetramethylene ether glycol 40 parts, diphenylmethane diisocyanate 10 parts, catalyst 1.5 parts, cystamine dihydrochloride 0.23 parts, and polyimide DMAc solution 30 parts.
[0007] Furthermore, the solvent is one or more of N,N-dimethylacetamide, N,N-dimethylformamide, and dimethyl sulfoxide.
[0008] Furthermore, the catalyst is dibutyltin dilaurate.
[0009] Furthermore, the polyimide DMAc solution is obtained by copolymerizing fluorinated polyimide solution with HFDA and ODA in DMAc solvent, with a molecular weight of 3.5 kJ and a solution concentration of 178 kJ. .
[0010] The steps of the method for preparing a repairable polyurea elastomer according to the present invention include: Step 1: Place N,N-dimethylacetamide into a reaction vessel, stir and heat, and simultaneously purge with nitrogen gas for protection; Step 2: Add polytetramethylene ether glycol to the reaction vessel, and place diphenylmethane diisocyanate (MDI) into a constant pressure dropping funnel; Step 3: Add the catalyst dibutyltin dilaurate to carry out the reaction and generate the prepolymer; Step 4: After the prepolymer solution cools to room temperature, add cystamine dropwise, reheat the mixture and continue the reaction. After the reaction is complete, the intermediate PU-S is obtained. Step 5: Reheat the reaction system, add polyimide solution, and stir for 3 days to obtain a homogeneous, phase-free mixed solution; Step 6: Transfer the solution to a vacuum device and remove the solvent by evaporation to obtain PU-PI elastomer; Step 7: Place the PU-PI elastomer in a vacuum environment at 80°C for 8 hours for post-treatment to ensure the material's performance stability and purity.
[0011] Furthermore, in step 1, 200 mL of N,N-dimethylacetamide was measured and placed into a reaction vessel, the stirring speed was 100 r / min, and the temperature was raised to 80 °C.
[0012] Furthermore, in step 2, 40g of polytetramethylene ether glycol was weighed and added to the reaction vessel, and 10g of diphenylmethane diisocyanate was placed in a constant pressure dropping funnel and added over a period of 30 minutes.
[0013] Furthermore, in step 3, 1.5 mL of the catalyst dibutyltin dilaurate was added dropwise, and the reaction was carried out at 80 °C for 1.5 hours.
[0014] Furthermore, in step 4, 0.23 g of cystamine was added dropwise, and the mixture was reheated to 40°C and the reaction was continued for 2 hours.
[0015] Furthermore, in step 5, the reaction system is reheated to 80°C, and 30 mL of polyimide solution is added.
[0016] The beneficial effects of this invention are: while maintaining high strength, the polyurethane elastomer significantly improves its self-healing ability; this is due to the introduction of a dynamic reversible disulfide bond (SS) structure and an optimized combination of chain extenders. Fluorinated polyimide rigid segments are introduced into the polyurea structure design, forming a more rigid microphase-separated nanostructure. By adjusting the polyimide ratio, this invention achieves precise control of the elastomer's microstructure, significantly improving the material's elastic modulus and stability in use, while ensuring the excellent corrosion resistance and water resistance of the polyurea elastomer.
[0017] Example Example 1: This embodiment discloses a high-strength, repairable polyurethane elastomer and its preparation method, which is composed of the following components by weight: 200 parts of N,N-dimethylacetamide, 40 parts of polytetramethylene ether glycol, 10 parts of diphenylmethane diisocyanate, 1.5 parts of dibutyltin dilaurate, 0.23 parts of cystamine dihydrochloride, and 30 parts of polyimide DMAc solution.
[0018] Step 1: Measure 200 mL of N,N-dimethylacetamide (DMAc) into a reaction vessel, stir at 100 r / min, heat to 80 ℃, and purge with nitrogen for protection; Step 2: Weigh 40 g of polytetramethylene ether glycol (PTMEG) and add it to the reaction vessel. Place 10 g of diphenylmethane diisocyanate (MDI) into a constant pressure dropping funnel and add it dropwise for 30 min. Step 3: Add 1.5 mL of the catalyst dibutyltin dilaurate (DBTDL) and react at 80 °C for 1.5 hours to generate the prepolymer; Step 4: After the prepolymer solution cools to room temperature, add 0.23 g of cystamine dropwise, reheat the mixture to 40°C, and continue the reaction for 2 hours. After the reaction is complete, intermediate PU-S is obtained. Step 5: Reheat the reaction system to 80°C, add 30 mL of laboratory-made polyimide DMAc solution, and stir for 3 days to obtain a homogeneous, phase-free mixed solution. Step 6: Transfer the solution to a vacuum device and remove the solvent by evaporation to obtain the PU-PI elastomer; Step 7: Place the PU-PI elastomer in a vacuum environment at 80°C for 8 hours for post-treatment to ensure the material's performance stability and purity.
[0019] Example 2: This embodiment discloses a high-strength, repairable polyurethane elastomer and its preparation method, which is composed of the following components by weight: 200 parts of N,N-dimethylacetamide, 40 parts of polytetramethylene ether glycol, 10 parts of diphenylmethane diisocyanate, 1.5 parts of dibutyltin dilaurate, 0.23 parts of 2,2-aminodiphenyl disulfide, and 30 parts of polyimide DMAc solution.
[0020] Step 1: Measure 200 mL of N,N-dimethylacetamide (DMAc) into a reaction vessel, stir at 100 r / min, heat to 80 ℃, and purge with nitrogen for protection; Step 2: Weigh 40 g of polytetramethylene ether glycol (PTMEG) and add it to the reaction vessel. Place 10 g of diphenylmethane diisocyanate (MDI) into a constant pressure dropping funnel and add it dropwise for 30 min. Step 3: Add 1.5 mL of the catalyst dibutyltin dilaurate (DBTDL) and react at 80 °C for 1.5 hours to generate the prepolymer; Step 4: After the prepolymer solution cools to room temperature, add 0.23 g of 2,2-aminodiphenyl disulfide dropwise, reheat the mixture to 40°C, and continue the reaction for 2 hours. After the reaction is complete, intermediate PU-S is obtained. Step 5: Reheat the reaction system to 80°C, add 30 mL of laboratory-made polyimide DMAc solution, and stir for 3 days to obtain a homogeneous, phase-free mixed solution. Step 6: Transfer the solution to a vacuum device and remove the solvent by evaporation to obtain the PU-PI elastomer; Step 7: Place the PU-PI elastomer in a vacuum environment at 80°C for 8 hours for post-treatment to ensure the material's performance stability and purity.
[0021] Example 3: This embodiment discloses a high-strength, repairable polyurethane elastomer and its preparation method, which is composed of the following components by weight: 200 parts of N,N-dimethylacetamide, 40 parts of polytetramethylene ether glycol, 10 parts of diphenylmethane diisocyanate, 1.5 parts of dibutyltin dilaurate, 0.23 parts of cystamine dihydrochloride, and 30 parts of polyimide DMAc solution.
[0022] Step 1: Measure 200 mL of N,N-dimethylacetamide (DMAc) into a reaction vessel, stir at 100 r / min, heat to 80 ℃, and purge with nitrogen for protection; Step 2: Weigh 40 g of polytetramethylene ether glycol (PTMEG) and add it to the reaction vessel. Place 10 g of diphenylmethane diisocyanate (MDI) into a constant pressure dropping funnel and add it dropwise for 30 min. Step 3: Add 1.5 mL of the catalyst dibutyltin dilaurate (DBTDL) and react at 80 °C for 1.5 hours to generate the prepolymer; Step 4: After the prepolymer solution cools to room temperature, add 0.23 g of cystamine dropwise, reheat the mixture to 40°C, and continue the reaction for 2 hours. After the reaction is complete, intermediate PU-S is obtained. Step 5: Reheat the reaction system to 80°C, add 15 mL of laboratory-made polyimide DMAc solution, and stir for 3 days to obtain a homogeneous, phase-free mixed solution. Step 6: Transfer the solution to a vacuum device and remove the solvent by evaporation to obtain the PU-PI elastomer; Step 7: Place the PU-PI elastomer in a vacuum environment at 80°C for 8 hours for post-treatment to ensure the material's performance stability and purity.
[0023] Example 4: This embodiment discloses a high-strength, repairable polyurethane elastomer and its preparation method, which is composed of the following components by weight: 200 parts of N,N-dimethylacetamide, 40 parts of polytetramethylene ether glycol, 10 parts of diphenylmethane diisocyanate, 1.5 parts of dibutyltin dilaurate, 0.23 parts of cystamine dihydrochloride, and 45 parts of polyimide DMAc solution.
[0024] Step 1: Measure 200 mL of N,N-dimethylacetamide (DMAc) into a reaction vessel, stir at 100 r / min, heat to 80 ℃, and purge with nitrogen for protection; Step 2: Weigh 40 g of polytetramethylene ether glycol (PTMEG) and add it to the reaction vessel. Place 10 g of diphenylmethane diisocyanate (MDI) into a constant pressure dropping funnel and add it dropwise for 30 min. Step 3: Add 1.5 mL of the catalyst dibutyltin dilaurate (DBTDL) and react at 80 °C for 1.5 hours to generate the prepolymer; Step 4: After the prepolymer solution cools to room temperature, add 0.23 g of cystamine dropwise, reheat the mixture to 40°C, and continue the reaction for 2 hours. After the reaction is complete, intermediate PU-S is obtained. Step 5: Reheat the reaction system to 80°C, add 45 mL of laboratory-made polyimide DMAc solution, and stir for 3 days to obtain a homogeneous, phase-free mixed solution. Step 6: Transfer the solution to a vacuum device and remove the solvent by evaporation to obtain the PU-PI elastomer; Step 7: Place the PU-PI elastomer in a vacuum environment at 80°C for 8 hours for post-treatment to ensure the material's performance stability and purity.
[0025] Example 5: This embodiment discloses a high-strength, repairable polyurethane elastomer and its preparation method, which is composed of the following components by weight: 200 parts of ethyl acetate, 40 parts of polytetramethylene ether glycol, 10 parts of diphenylmethane diisocyanate, 1.5 parts of dibutyltin dilaurate, 0.23 parts of cystamine dihydrochloride, and 30 parts of polyimide DMAc solution.
[0026] Step 1: Measure 200 mL of N,N-dimethylacetamide (DMAc) into a reaction vessel, stir at 100 r / min, heat to 80 ℃, and purge with nitrogen for protection; Step 2: Weigh 40 g of polytetramethylene ether glycol (PTMEG) and add it to the reaction vessel. Place 10 g of diphenylmethane diisocyanate (MDI) into a constant pressure dropping funnel and add it dropwise for 30 min. Step 3: Add 1.5 mL of the catalyst dibutyltin dilaurate (DBTDL) and react at 80 °C for 1.5 hours to generate the prepolymer; Step 4: After the prepolymer solution cools to room temperature, add 0.23 g of cystamine dropwise, reheat the mixture to 40°C, and continue the reaction for 2 hours; after the reaction is complete, the intermediate PU-S is obtained. Step 5: Reheat the reaction system to 80°C, add 45 mL of laboratory-made polyimide DMAc solution, and stir for 3 days to obtain a homogeneous, phase-free mixed solution. Step 6: Transfer the solution to a vacuum device and remove the solvent by evaporation to obtain the PU-PI elastomer; Step 7: Place the PU-PI elastomer in a vacuum environment at 80°C for 8 hours for post-treatment to ensure the material's performance stability and purity.
[0027] Example 6: This embodiment discloses a high-strength, repairable polyurethane elastomer and its preparation method, which is composed of the following components by weight: 200 parts of N,N-dimethylformamide (DMF), 40 parts of polytetramethylene ether glycol, 10 parts of diphenylmethane diisocyanate, 1.5 parts of dibutyltin dilaurate, 0.23 parts of cystamine dihydrochloride, and 30 parts of polyimide DMAc solution.
[0028] Step 1: Measure 200 mL of N,N-dimethylacetamide (DMAc) into a reaction vessel, stir at 100 r / min, heat to 80 ℃, and purge with nitrogen for protection; Step 2: Weigh 40 g of polytetramethylene ether glycol (PTMEG) and add it to the reaction vessel. Place 10 g of diphenylmethane diisocyanate (MDI) into a constant pressure dropping funnel and add it dropwise for 30 min. Step 3: Add 1.5 mL of the catalyst dibutyltin dilaurate (DBTDL) and react at 80 °C for 1.5 hours to generate the prepolymer; Step 4: After the prepolymer solution cools to room temperature, add 0.23 g of cystamine dropwise, reheat the mixture to 40°C, and continue the reaction for 2 hours. After the reaction is complete, intermediate PU-S is obtained. Step 5: Reheat the reaction system to 80°C, add 45 mL of laboratory-made polyimide DMAc solution, and stir for 3 days to obtain a homogeneous, phase-free mixed solution. Step 6: Transfer the solution to a vacuum device and remove the solvent by evaporation to obtain the PU-PI elastomer; Step 7: Place the PU-PI elastomer in a vacuum environment at 80°C for 8 hours for post-treatment to ensure the material's performance stability and purity.
[0029] Comparative Example 1: This embodiment discloses a high-strength, repairable polyurethane elastomer and its preparation method, which is composed of the following components by weight: 200 parts of N,N-dimethylacetamide, 40 parts of polytetramethylene ether glycol, 10 parts of diphenylmethane diisocyanate, 1.5 parts of dibutyltin dilaurate, 0.23 parts of 1,4-butanediamine (BDA), and 30 parts of polyimide DMAc solution.
[0030] Step 1: Measure 200 mL of N,N-dimethylacetamide (DMAc) into a reaction vessel, stir at 100 r / min, heat to 80 ℃, and purge with nitrogen for protection; Step 2: Weigh 40 g of polytetramethylene ether glycol (PTMEG) and add it to the reaction vessel. Place 10 g of diphenylmethane diisocyanate (MDI) into a constant pressure dropping funnel and add it dropwise for 30 min. Step 3: Add 1.5 mL of the catalyst dibutyltin dilaurate (DBTDL) and react at 80 °C for 1.5 hours to generate the prepolymer; Step 4: After the prepolymer solution cools to room temperature, add 0.23 g of BDA dropwise, reheat the mixture to 40°C, and continue the reaction for 2 hours. After the reaction is complete, the intermediate PU-S is obtained. Step 5: Reheat the reaction system to 80°C, add 45 mL of laboratory-made polyimide DMAc solution, and stir for 3 days to obtain a homogeneous, phase-free mixed solution. Step 6: Transfer the solution to a vacuum device and remove the solvent by evaporation to obtain the PU-PI elastomer; Step 7: Place the PU-PI elastomer in a vacuum environment at 80°C for 8 hours for post-treatment to ensure the material's performance stability and purity.
[0031] Comparative Example 2: This embodiment discloses a high-strength, repairable polyurethane elastomer and its preparation method, which is composed of the following components by weight: 200 parts of N,N-dimethylacetamide, 40 parts of polytetramethylene ether glycol, 10 parts of diphenylmethane diisocyanate, 1.5 parts of dibutyltin dilaurate, 0.23 parts of cystamine, and 60 parts of polyimide DMAc solution.
[0032] Step 1: Measure 200 mL of N,N-dimethylacetamide (DMAc) into a reaction vessel, stir at 100 r / min, heat to 80 ℃, and purge with nitrogen for protection; Step 2: Weigh 40 g of polytetramethylene ether glycol (PTMEG) and add it to the reaction vessel. Place 10 g of diphenylmethane diisocyanate (MDI) into a constant pressure dropping funnel and add it dropwise for 30 min. Step 3: Add 1.5 mL of the catalyst dibutyltin dilaurate (DBTDL) and react at 80 °C for 1.5 hours to generate the prepolymer; Step 4: After the prepolymer solution cools to room temperature, add 0.23 g of cystamine dropwise, reheat the mixture to 40°C, and continue the reaction for 2 hours. After the reaction is complete, intermediate PU-S is obtained. Step 5: Reheat the reaction system to 80°C, add 60 mL of laboratory-made polyimide DMAc solution, and stir for 3 days to obtain a homogeneous, phase-free mixed solution. Step 6: Transfer the solution to a vacuum device and remove the solvent by evaporation to obtain the PU-PI elastomer; Step 7: Place the PU-PI elastomer in a vacuum environment at 80°C for 8 hours for post-treatment to ensure the material's performance stability and purity.
[0033] Comparative Example 3: This embodiment discloses a high-strength, repairable polyurethane elastomer and its preparation method, which is composed of the following components by weight: 200 parts of N,N-dimethylacetamide, 40 parts of polytetramethylene ether glycol, 10 parts of diphenylmethane diisocyanate, 1.5 parts of dibutyltin dilaurate, 0.23 parts of cystamine, and 60 parts of polyimide DMAc solution.
[0034] Step 1: Measure 200 mL of N,N-dimethylacetamide (DMAc) into a reaction vessel, stir at 100 r / min, heat to 80 ℃, and purge with nitrogen for protection; Step 2: Weigh 40 g of polytetramethylene ether glycol (PTMEG) and add it to the reaction vessel. Place 10 g of diphenylmethane diisocyanate (MDI) into a constant pressure dropping funnel and add it dropwise for 30 min. Step 3: Add 1.5 mL of the catalyst dibutyltin dilaurate (DBTDL) and react at 80 °C for 1.5 hours to generate the prepolymer; Step 4: After the prepolymer solution cools to room temperature, add 0.23 g of cystamine dropwise, reheat the mixture to 40°C, and continue the reaction for 2 hours; after the reaction is complete, intermediate PU-S is obtained; Step 5: Reheat the reaction system to 80°C, add 60 mL of laboratory-made polyimide DMAc solution, and stir for 3 days to obtain a homogeneous, phase-free mixed solution. Step 6: Transfer the solution to a vacuum device and remove the solvent by evaporation to obtain the PU-PI elastomer; Step 7: Place the PU-PI elastomer in a vacuum environment at 80°C for 8 hours for post-treatment to ensure the material's performance stability and purity.
[0035] The high-strength, self-healing polyurethane elastomer of this invention has broad application prospects, especially in fields requiring a balance between mechanical properties and repair capabilities. Firstly, in terms of self-healing coatings, this elastomer effectively addresses performance degradation caused by mechanical damage or environmental factors. Traditional coating materials often lack self-healing capabilities, while the material of this invention significantly extends coating life and reduces maintenance and replacement costs. Currently, commercially available self-healing elastomer materials still face problems such as insufficient durability, slow repair rates, and poor environmental adaptability. This invention solves these problems by optimizing the dynamic characteristics of chemical bonds and the structure of polymer chains. Future improvements include further enhancing repair efficiency, improving chemical corrosion resistance, and exploring multifunctional applications to meet the needs of different fields.
[0036] The performance of a high-strength, repairable polyurethane elastomer obtained in Examples 1 to 6 and Comparative Examples 1 to 3 was tested, and the results are shown in the table below:
[0037] This invention provides a novel process for preparing high-strength, repairable polyurea elastomers, successfully broadening the application range of fluorinated polyimide materials. In Experiment 1, N,N-dimethylacetamide was chosen as the solvent because its low polarity helps maintain reaction uniformity and effectively reduces the possibility of side reactions. Comparative results from Experiment 2 and Comparative Example 1 show that replacing the polyurea chain extender from cystamine to other materials limits the dynamic recombination ability of the elastomer molecular chains, leading to a significant decrease in its elongation at break and repairability. Experiment 3 and Comparative Example 2, by precisely adjusting the content of rigid polyimide segments, successfully achieved an optimized balance between strength and elasticity in the polyurea elastomer.
[0038] 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 substitutions, and improvements made to the above embodiments without departing from the scope of the present invention, based on the technical essence of the present invention and within the spirit and principles of the present invention, shall still fall within the protection scope of the present invention.
Claims
1. A repairable polyurea elastomer, characterized in that, The product comprises a solvent, polytetramethylene ether glycol, diphenylmethane diisocyanate, a catalyst, cystamine dihydrochloride, and a polyimide DMAc solution, wherein the mass fractions of each component are as follows: solvent 200 parts, polytetramethylene ether glycol 40 parts, diphenylmethane diisocyanate 10 parts, catalyst 1.5 parts, cystamine dihydrochloride 0.23 parts, and polyimide DMAc solution 30 parts.
2. The repairable polyurea elastomer according to claim 1, characterized in that, The solvent is one or more of N,N-dimethylacetamide, N,N-dimethylformamide, and dimethyl sulfoxide.
3. The repairable polyurea elastomer according to claim 1, characterized in that, The catalyst is dibutyltin dilaurate.
4. The repairable polyurea elastomer according to claim 1, characterized in that, The polyimide DMAc solution is obtained by copolymerizing fluorinated polyimide solution with HFDA and ODA in DMAc solvent, with a molecular weight of 3.5 kJ and a solution concentration of 178%. .
5. A method for preparing the repairable polyurea elastomer according to any one of claims 1 to 4, characterized in that, The specific steps include: Step 1: Place N,N-dimethylacetamide into a reaction vessel, stir and heat, and simultaneously purge with nitrogen gas for protection; Step 2: Add polytetramethylene ether glycol to the reaction vessel, and place diphenylmethane diisocyanate (MDI) into a constant pressure dropping funnel; Step 3: Add the catalyst dibutyltin dilaurate to carry out the reaction and generate the prepolymer; Step 4: After the prepolymer solution cools to room temperature, add cystamine dropwise, reheat the mixture and continue the reaction. After the reaction is complete, the intermediate PU-S is obtained. Step 5: Reheat the reaction system, add polyimide solution, and stir for 3 days to obtain a homogeneous, phase-free mixed solution; Step 6: Transfer the solution to a vacuum device and remove the solvent by evaporation to obtain PU-PI elastomer; Step 7: Place the PU-PI elastomer in a vacuum environment at 80°C for 8 hours for post-treatment to ensure the material's performance stability and purity.
6. The method for preparing a repairable polyurea elastomer according to claim 5, characterized in that, In step 1, 200 mL of N,N-dimethylacetamide was measured and placed into a reaction vessel. The stirring speed was 100 r / min, and the temperature was raised to 80 °C.
7. The method for preparing a repairable polyurea elastomer according to claim 5, characterized in that, In step 2, 40g of polytetramethylene ether glycol was weighed and added to the reaction vessel, and 10g of diphenylmethane diisocyanate was placed in a constant pressure dropping funnel and added over a period of 30 minutes.
8. The method for preparing a repairable polyurea elastomer according to claim 5, characterized in that, In step 3, 1.5 mL of the catalyst dibutyltin dilaurate was added dropwise, and the reaction was carried out at 80 °C for 1.5 hours.
9. The method for preparing a repairable polyurea elastomer according to claim 5, characterized in that, In step 4, add 0.23 g of cystamine, reheat the mixture to 40°C, and continue the reaction for 2 hours.
10. The method for preparing a repairable polyurea elastomer according to claim 5, characterized in that, In step 5, the reaction system is reheated to 80°C, and 30 mL of polyimide solution is added.