Preparation method of two-dimensional high-strength coating material

Abstract

The invention provides a preparation method of a two-dimensional high-strength coating material, which comprises the following steps: under the protection of inert gas, dissolving melamine and trimesoyl chloride as reaction monomers in a solution A, adding triethylamine as an acid-binding agent, and promoting amidation reaction through magnetic stirring; after the reaction is finished, washing with saturated saline solution and NaHCO3 to remove impurities, and then obtaining high-purity two-dimensional polymer powder through the steps of solution mixing, ultrasonic treatment, centrifugal separation and the like. And finally, dissolving polymer powder in the solution F to prepare two-dimensional polymer solutions with different concentrations, and coating the two-dimensional polymer solutions on the surface of a substrate pretreated by acetone and isopropanol to obtain a flat and compact coating film. The triethylamine is adopted as the acid binding agent, so that the purity and the reaction efficiency of the polymer are improved, the preparation controllability and the structural uniformity of the coating material are remarkably improved, and the high-performance coating requirements in the fields of machinery, chemical protection and the like are met.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and in particular to a method for preparing a two-dimensional high-strength coating material. Background Art

[0002] Polymer materials such as plastics, rubber and glass used in daily life are essentially composed of single molecular chains, which are extended to form a three-dimensional structure with gaps. This gap structure makes the material less airtight and easily penetrated by gas and water molecules, resulting in insufficient mechanical strength, corrosion resistance and wear resistance. In contrast, two-dimensional materials have great potential in improving the performance of coating materials due to their highly regular molecular arrangement and strong airtightness. In particular, coating materials based on two-dimensional polymers can achieve higher mechanical properties and chemical stability by optimizing their structural properties.

[0003] In the study of two-dimensional materials, two-dimensional polymers based on melamine and trimesoyl chloride have received extensive attention. These monomers generate continuous and uniform two-dimensional materials connected by amide bonds through irreversible polycondensation reactions. Its dense sheet structure can significantly improve the airtightness of the material, and gas and water molecules cannot penetrate, thereby giving the material excellent mechanical properties, corrosion resistance and wear resistance. However, the preparation of two-dimensional polymers has strict requirements on reaction conditions. For example, in the amidation reaction, the selection of acid binding agents and reaction conditions (such as concentration, temperature, etc.) will directly affect the efficiency of the polymerization reaction and the structure of the product. In the prior art, the method of preparing two-dimensional polymer materials by manually controlling the acid binding agent and the reaction environment often has problems such as complex preparation process, poor controllability, and unstable product quality.

[0004] Although amide-based two-dimensional polymer materials exhibit excellent properties, their preparation process still faces many challenges:

[0005] 1. Complex reaction environment control: The preparation of two-dimensional polymers requires strict control of the humidity and temperature of the reaction environment to avoid moisture and temperature fluctuations affecting the reaction efficiency and product quality, which increases the difficulty of experimental operation.

[0006] 2. Unclear selection of acid-binding agent: The use conditions (including concentration, order of addition, etc.) of different acid-binding agents (such as triethylamine) have a great influence on the reaction rate and the uniformity and density of the final product, but there is a lack of unified standardized operation in the prior art.

[0007] 3. Unstable thin film coating preparation: When two-dimensional polymer materials are used in actual coating applications, the thickness and uniformity of the coating have a significant impact on the material properties. The existing technology has deficiencies in solvent selection, concentration adjustment and substrate cleaning in the preparation of thin film coatings, resulting in large fluctuations in coating performance.

[0008] In summary, the existing technology urgently needs an improved method for preparing two-dimensional high-strength coating materials, which can improve the material preparation efficiency and the uniformity and performance stability of the coating by optimizing the reaction conditions and selecting an appropriate solvent system and process flow, so as to better meet the actual application needs. Summary of the invention

[0009] According to the technical problems raised above, a method for preparing a two-dimensional high-strength coating material is provided. The present invention uses melamine and trimesoyl chloride as reaction monomers, triethylamine as an acid binding agent, and provides an alkaline environment to promote the amidation reaction under the protection of an inert gas, thereby improving the purity and reaction efficiency of the polymer. Under optimized process conditions, a two-dimensional polymer material connected by an amide bond is prepared, and a uniform and dense thin film coating is obtained by controlling the concentration of the polymer solution and the coating process. The obtained material can be widely used in the preparation of coating products, and its structural stability and uniformity ensure a high level of mechanical properties, corrosion resistance and wear resistance, meeting the needs of practical applications.

[0010] The technical means adopted by the present invention are as follows:

[0011] A method for preparing a two-dimensional high-strength coating material comprises the following steps:

[0012] S1. In a glove box, add 1.3-5.2 g of melamine into a 250 mL round-bottom flask, then add 90 mL of solution A and 5-30 mL of triethylamine, then slowly add 2.6 g of trimesoyl chloride, seal the flask, and stir magnetically at 2000 rpm for 8 h.

[0013] S2, filtering the polymer solution obtained in step S1 to remove triethylamine hydrochloride generated in the reaction and unreacted melamine; washing with saturated saline and saturated NaHCO3 in sequence to obtain solution B;

[0014] S3, using ethanol and n-hexane in a volume ratio of 1:1 to prepare solution C, using water and acetone in a volume ratio of 1:1 to prepare solution D, mixing solution B and solution C in a volume ratio of 1:12-14, and ultrasonically making it turbid to obtain solution E;

[0015] S4. Solution E is further centrifuged to obtain a light yellow precipitate, which is washed three times with 20 mL of solution D and vacuum dried to obtain a light yellow two-dimensional polymer powder;

[0016] S5. Mix the two-dimensional polymer powder with solution F, prepare two-dimensional polymer solutions of different concentrations, and apply them on the surface of the substrate to form two-dimensional high-strength coatings of different thicknesses.

[0017] Furthermore, in step S1, an inert gas is continuously introduced into the glove box, the ambient humidity is controlled below 10%, and the temperature is controlled at 15-30°C.

[0018] Further, in step S1, solution A is N,N-dimethylacetamide or N-methylpyrrolidone.

[0019] Further, in step S4, the vacuum drying temperature is 100° C. and the time is 8 hours.

[0020] Further, in step S5, solution F includes trifluoroacetic acid, N,N-dimethylformamide or N,N-dimethylacetamide.

[0021] Furthermore, in step S5, the concentration of the two-dimensional polymer solution is 0.5-15 mg / mL.

[0022] Furthermore, the substrate of the two-dimensional high-strength coating is polystyrene.

[0023] Furthermore, in step S5, the substrate is pre-cleaned before coating using acetone and isopropyl alcohol to remove contaminants.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] 1. The present invention uses melamine and trimesoyl chloride as main reaction monomers. These two raw materials have a benzene ring structure and can grow stably in a two-dimensional plane, avoiding the problem of uneven structure caused by traditional monomers. Trimesoyl chloride undergoes an amidation reaction with melamine to form a dense sheet structure connected by amide bonds, further improving the mechanical strength and airtightness of the material and preventing the penetration of gas and water molecules.

[0026] 2. The present invention significantly improves the efficiency of the amidation reaction by using triethylamine as an acid binding agent. Triethylamine provides a suitable alkaline environment, promotes the chemical reaction between melamine and trimesoyl chloride, and effectively inhibits the occurrence of side reactions. This optimized reaction condition not only improves the purity of the polymer, but also makes the sheet structure of the two-dimensional polymer more regular, ensuring the consistency of the material in performance.

[0027] 3. The two-dimensional high-strength coating material prepared by the present invention can form a flat, uniform and dense thin film coating on the substrate surface through a reasonable coating process. The coating has excellent mechanical properties, corrosion resistance and wear resistance, and meets the application requirements of high-strength protection and mechanical fields.

[0028] In summary, the present invention has successfully prepared a two-dimensional high-strength coating material with high purity, high strength and structural uniformity by optimizing raw material selection, reaction principle and preparation process. This material not only has significant advantages in coating performance, but also improves the efficiency and controllability of material preparation by optimizing the production process. It is suitable for high-performance coating requirements in the fields of machinery and chemical protection, and has broad industrial application prospects. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] The present invention provides a method for preparing a two-dimensional high-strength coating material, which specifically comprises the following steps:

[0031] Add 1.3-5.2g of melamine to a 250mL round-bottom flask, then add 90mL of solution A (including N,N-dimethylacetamide, N-methylpyrrolidone) and 5-30mL of triethylamine (TEA), and then slowly add 2.6g of trimesoyl chloride. After sealing, stir magnetically at 2000rpm for 8h, filter out triethylamine hydrochloride and unreacted melamine in the polymer solution. Then wash with saturated brine and saturated NaHCO3 in turn, and finally obtain solution B.

[0032] Solution C was prepared using ethanol and n-hexane in a volume ratio of 1:1, and solution D was prepared using water and acetone in a volume ratio of 1:1. Solution B and solution C were mixed in a volume ratio of 1:12-14, and ultrasonically made turbid to obtain solution E. Solution E was further centrifuged to obtain a light yellow precipitate of the centrifugal product, and the light yellow precipitate was washed three times with 20 mL of solution D, and vacuum dried at 100°C for 8 hours to obtain a light yellow powder.

[0033] It is worth noting that all materials are guaranteed to be pure, and the synthesis steps are completed in a glove box. Inert gas (including argon and nitrogen) is continuously passed through the glove box to ensure that the relative humidity of the environment is below 10% to avoid the influence of moisture in the environment on the experimental process. The temperature in the glove box is controlled at 15-30°C to avoid the influence of too high or too low ambient temperature on the experimental process.

[0034] The polymer powder was dissolved in different amounts of solution F (including trifluoroacetic acid, N,N-dimethylformamide, N,N-dimethylacetamide), and polymer thin film coatings of different thicknesses were prepared by preparing polymer solutions of different concentrations (0.5, 1, 2, 5, 10 and 15 mg / mL). These solutions were poured on the coating substrate, and a flat and uniform thin film coating was obtained on the substrate after the solvent was evaporated. The substrate surface was pre-cleaned with acetone and isopropanol to prevent dust and other contaminants from affecting the uniformity and continuity of the film.

[0035] Example 1

[0036] In a glove box, 1.3 g of melamine, 2.6 g of trimesoyl chloride, 90 mL of N-methylpyrrolidone and 5 mL of triethylamine were added to a 250 mL round-bottom flask, and the magnetic speed was controlled at 2000 rpm. The resulting polymer material was mixed with trifluoroacetic acid to form a 10 mg / mL mixed solution, which was coated on the surface of the polystyrene sample.

[0037] Example 2

[0038] In a glove box, 5.2 g of melamine, 2.6 g of trimesoyl chloride, 90 mL of N-methylpyrrolidone and 20 mL of triethylamine were added to a 250 mL round-bottom flask, and the magnetic speed was controlled at 2000 rpm. The resulting polymer material was mixed with trifluoroacetic acid to form a 15 mg / mL mixed solution, which was coated on the surface of the polystyrene sample.

[0039] Example 3

[0040] In a glove box, 3.2 g of melamine, 2.6 g of trimesoyl chloride, 90 mL of N-methylpyrrolidone and 20 mL of triethylamine were added to a 250 mL round-bottom flask, and the magnetic speed was controlled at 2000 rpm. The resulting polymer material was mixed with trifluoroacetic acid to form a 0.5 mg / mL mixed solution, which was coated on the surface of the polystyrene sample.

[0041] Comparative Example 1

[0042] In a glove box, 1.3 g of melamine, 2.6 g of trimesoyl chloride, 90 mL of N-methylpyrrolidone and 5 mL of pyridine were added to a 250 mL round-bottom flask, and the magnetic speed was controlled at 2000 rpm. The resulting polymer material was mixed with trifluoroacetic acid to form a 10 mg / mL mixed solution, which was coated on the surface of the polystyrene sample.

[0043] Comparative Example 2

[0044] In a glove box, 5.2 g of melamine, 2.6 g of trimesoyl chloride, 90 mL of N-methylpyrrolidone and 20 mL of pyridine were added to a 250 mL round-bottom flask, and the magnetic speed was controlled at 2000 rpm. The resulting polymer material was mixed with trifluoroacetic acid to form a 15 mg / mL mixed solution, which was coated on the surface of the polystyrene sample.

[0045] Comparative Example 3

[0046] In a glove box, 3.2 g of melamine, 2.6 g of trimesoyl chloride, 90 mL of N-methylpyrrolidone and 20 mL of pyridine were added to a 250 mL round-bottom flask, and the magnetic speed was controlled at 2000 rpm. The resulting polymer material was mixed with trifluoroacetic acid to form a 0.5 mg / mL mixed solution, which was coated on the surface of the polystyrene sample.

[0047] The coating materials prepared in Examples 1-3 and Comparative Examples 1-3 were tested for ultimate tensile strength, water absorption and Brinell hardness. The specific test conditions were as follows:

[0048] The tensile ultimate strength test is carried out in accordance with GB / T 1040.1 and GB / T 1040.2. At least 5 type 1B specimens are taken in each direction of the sheet for testing. The test speed is (50±5) mm / min.

[0049] The test standards for water absorption mainly refer to GB / T 8810-2005 and GB / T 10801.1-2021. The test conditions include immersion in water at (23±2)℃ for 96h, and the average water absorption of three specimens is taken as the final result.

[0050] Brinell hardness testing follows ISO 6506 and ASTM E10 standards.

[0051] The test results are shown in Table 1.

[0052] Table 1 Coating material performance test comparison table

[0053] PS Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Yield / % / 99.7 99.9 99.8 94.0 94.7 94.5 Tensile ultimate strength / MPa 51.5 77.8 77.8 77.7 75.5 76.7 75 Water absorption / % 0.26 0.03 0.03 0.03 0.03 0.03 0.03 Brinell hardness 57 70 70 69.9 67.5 68.9 66.7

[0054] From the results in Table 1, we can see that:

[0055] In terms of yield: the yields of Examples 1-3 are all between 99.7% and 99.9%, which are significantly improved compared to 94.0% to 94.7% of Comparative Examples 1-3, indicating that after optimizing the reaction conditions, the preparation process of the present invention improves the synthesis efficiency of the material, reduces the waste of raw materials, and improves the production stability and economic benefits.

[0056] In terms of tensile strength: after the coating treatment of the present invention, the tensile strength of PS is increased from 51.5MPa to 77.8MPa, which is further enhanced compared with comparative examples 1-3 (75.0-76.7MPa). The two-dimensional polymer coating used in the present invention can effectively enhance the mechanical strength of the base material and improve its bearing capacity, making the coating more suitable for high-strength application scenarios.

[0057] In terms of water absorption: the water absorption of all embodiments is reduced to 0.03%, which is the same as the comparative data, but compared with the original water absorption of PS (0.26%), the water absorption is greatly reduced, indicating that the high airtightness of the coating can effectively prevent the penetration of water, improve the moisture resistance of the material, and extend the service life.

[0058] In terms of Brinell hardness: after coating treatment, the Brinell hardness of Examples 1-3 are 70.0, 70.0, and 69.9, respectively, which is significantly higher than 57 of PS and higher than Comparative Examples 1-3 (66.7-68.9). This indicates that the coating can enhance the wear resistance of the base material, improve its compression and scratch resistance in a high friction environment, and thus improve the service life and reliability of the material.

[0059] In summary, the coating preparation method of the present invention is simple, easy to operate, low in cost and less polluting. The regular arrangement of monomers on a two-dimensional plane significantly improves the strength and airtightness of the coating. The use of triethylamine as an acid binding agent improves the degree of reaction and the reaction yield. After the coating is added to the surface of polystyrene, its tensile strength and Brinell hardness are significantly improved; in addition, its water absorption rate is also greatly reduced, which prolongs its service life, providing a better choice for the application of high-performance, environmentally friendly coating materials.

[0060] The above embodiments are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the above embodiments, a person of ordinary skill in the art should understand that any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a two-dimensional high-strength coating material, characterized in that: The following steps are involved: S1. In a glove box, add 1.3-5.2 g of melamine into a 250 mL round-bottom flask, then add 90 mL of solution A and 5-30 mL of triethylamine, then slowly add 2.6 g of trimesoyl chloride, seal the flask, and stir magnetically at 2000 rpm for 8 h. S2, filtering the polymer solution obtained in step S1 to remove triethylamine hydrochloride generated in the reaction and unreacted melamine; washing with saturated saline and saturated NaHCO3 in sequence to obtain solution B; S3, using ethanol and n-hexane in a volume ratio of 1:1 to prepare solution C, using water and acetone in a volume ratio of 1:1 to prepare solution D, mixing solution B and solution C in a volume ratio of 1:12-14, and ultrasonically making it turbid to obtain solution E; S4. Solution E is further centrifuged to obtain a light yellow precipitate, which is washed three times with 20 mL of solution D and vacuum dried to obtain a light yellow two-dimensional polymer powder; S5. Mix the two-dimensional polymer powder with solution F, prepare two-dimensional polymer solutions of different concentrations, and apply them on the surface of the substrate to form two-dimensional high-strength coatings of different thicknesses.

2. The method for preparing a two-dimensional high-strength coating material according to claim 1, characterized in that: In step S1, an inert gas is continuously introduced into the glove box, the ambient humidity is controlled below 10%, and the temperature is controlled at 15-30°C.

3. The method for preparing a two-dimensional high-strength coating material according to claim 1, characterized in that: In step S1, solution A is N,N-dimethylacetamide or N-methylpyrrolidone.

4. The method for preparing a two-dimensional high-strength coating material according to claim 1, characterized in that: In step S4, the vacuum drying temperature is 100° C. and the time is 8 hours.

5. The method for preparing a two-dimensional high-strength coating material according to claim 1, characterized in that: In step S5 , solution F includes trifluoroacetic acid, N,N-dimethylformamide or N,N-dimethylacetamide.

6. The method for preparing a two-dimensional high-strength coating material according to claim 1, characterized in that: In step S5, the concentration of the two-dimensional polymer solution is 0.5-15 mg / mL.

7. The method for preparing a two-dimensional high-strength coating material according to claim 1, characterized in that: The substrate of the two-dimensional high-strength coating is polystyrene.

8. The method for preparing a two-dimensional high-strength coating material according to claim 7, characterized in that: In step S5, the substrate is pre-cleaned before coating using acetone and isopropyl alcohol to remove contaminants.