Preparation method of catechol copolymer underwater adhesive

Abstract

The invention belongs to the technical field of macromolecular underwater materials, and discloses a preparation method of a catechol copolymer underwater adhesive. The preparation method of the catechol copolymer comprises the following steps: S1, preparing a DPE-Bn monomer by taking 3, 4-dihydroxyphenethyl alcohol, potassium carbonate, benzyl bromide and acetonitrile as raw materials under the conditions of nitrogen protection and 50 DEG C oil bath; s2, mixing the DPE-Bn monomer, triethylamine and dichloromethane, adding acryloyl chloride under an ice-water bath condition, and reacting to obtain a DA-Bn monomer; s3, carrying out polymerization reaction on the DA-Bn monomer, 5-hexene-1 alcohol, azodiisobutyronitrile and N, N-dimethylformamide under an oil bath condition of 80 DEG C, and after the reaction is finished, putting a reactant into methanol to precipitate, so as to obtain a PDA-Bn polymer; and S4, mixing the PDA-Bn polymer with dichloromethane, adding trimethyl iodosilane under an ice-water bath condition, adding a hydrochloric acid solution after the reaction is finished, carrying out reactant precipitation, and dissolving the precipitate with N, N-dimethylformamide to obtain a polymer P (DA-co-He), namely the catechol copolymer.

Description

Technical Field

[0001] The invention belongs to the technical field of macromolecular underwater materials, and particularly relates to a method for preparing a catechol copolymer underwater adhesive. Background Art

[0002] Adhesives are widely used in a variety of fields, including aerospace, automotive, machinery, and marine engineering. In most cases, these adhesives only form permanent or reversible bonds to dry solid surfaces in air. However, many applications require adhesion to wet surfaces or surfaces submerged in aqueous media, such as in underwater repair, the marine industry, and ship repair.

[0003] Underwater adhesives are effectively used in many applications, including the maintenance of hydraulic engineering projects and underwater equipment. They can significantly simplify and expedite these construction processes, extending the service life of infrastructure or equipment, and are therefore of great significance. Vessels operate at sea for extended periods, making it difficult to dock for repairs when damaged. This requires a high-strength, corrosion-resistant, age-resistant adhesive with long-lasting stability underwater. Therefore, developing an adhesive with these advantages is of great significance in my country's marine engineering field. Summary of the Invention

[0004] In view of this, and to address the issues raised in the aforementioned background art, the present invention aims to provide a method for preparing a catechol copolymer underwater adhesive with strong practicality, high adhesion strength, and excellent stability. Specifically, a catechol-containing polymer was prepared based on the strong dopamine mucus secreted by mussels, which allows them to firmly adhere to ship hulls and reef surfaces. This polymer achieves super-strong underwater adhesion through π-π conjugation between the catechols, hydrogen bonding with the metal substrate, and coordination. Isocyanate modification introduces isocyanate groups, allowing it to crosslink underwater with water, achieving self-curing of the adhesive.

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

[0006] Option 1

[0007] A catechol copolymer having the structure shown in the following formula:

[0008] .

[0009] Option 2

[0010] A method for preparing a catechol copolymer comprises the following steps:

[0011] S1. DPE-Bn monomer was prepared from 3,4-dihydroxyphenylethanol, potassium carbonate, benzyl bromide, and acetonitrile under nitrogen protection and an oil bath at 50°C.

[0012] S2. After mixing DPE-Bn monomer, triethylamine and dichloromethane, acryloyl chloride was added under ice water bath condition, and DA-Bn monomer was obtained after the reaction was completed;

[0013] S3. DA-Bn monomer, 5-hexene-1-ol, azobisisobutyronitrile and N,N-dimethylformamide were placed in an oil bath at 80°C for polymerization reaction, and PDA-Bn polymer was obtained after the reaction was completed by precipitating the reaction product in methanol;

[0014] S4. After mixing PDA-Bn polymer and dichloromethane, trimethylsilyl iodide was added under ice water bath condition, and then hydrochloric acid solution was added for precipitating the reaction product, and the precipitate was dissolved in N,N-dimethylformamide to obtain polymer P(DA-co-He), i.e. catechol copolymer.

[0015] Preferably, in the step S1:

[0016] 3,4-dihydroxyphenethyl alcohol, potassium carbonate, benzyl bromide and acetonitrile were mixed in a mass volume ratio of 4-5:11-14:10-12:100 g / mL under nitrogen protection and oil bath condition at 50°C for 5h;

[0017] After the reaction was completed, filtration, 40°C rotary evaporation concentration, ethyl acetate: water = 1:1 extraction, anhydrous magnesium sulfate drying, 35°C rotary evaporation concentration were performed to obtain DPE-Bn monomer.

[0018] Preferably, in the step S2:

[0019] The mass volume ratio g / mL of DPE-Bn monomer, triethylamine, dichloromethane and acryloyl chloride was 4-5:5-6:20:1-2;

[0020] The reaction was performed under ice water bath condition for 12h, and then rotary evaporation concentration was performed at room temperature 25°C, and column chromatography purification was performed with n-hexane: ethyl acetate = 5:1 to obtain DA-Bn monomer.

[0021] Preferably, in the step S3:

[0022] The mass volume ratio mg / mL of DA-Bn monomer, 5-hexene-1-ol, azobisisobutyronitrile and N,N-dimethylformamide was 700-800:200:9-10:2;

[0023] The polymerization reaction was performed in an oil bath at 80°C for 2h.

[0024] Preferably, in the step S4:

[0025] The mass volume ratio of the PDA-Bn polymer, dichloromethane and trimethylsilyl iodide is 1:10:1 g / mL;

[0026] The reaction was carried out under ice-water bath conditions for 12 hours. After the reaction was completed, hydrochloric acid solution was added to precipitate the reactants, and then the precipitate was dissolved with N,N-dimethylformamide, extracted with N,N-dimethylformamide:n-hexane = 1:1, washed with saturated brine, and freeze-dried at -50°C for 24 hours to obtain a polymer P(DA-co-He), i.e., a catechol copolymer.

[0027] Option 3

[0028] A use of the catechol copolymer disclosed above in preparing an underwater adhesive.

[0029] Option 4

[0030] An underwater adhesive adopts the catechol copolymer disclosed above as a raw material.

[0031] Plan 5

[0032] A method for preparing an underwater adhesive comprises the following steps:

[0033] Using the catechol copolymer disclosed above as a raw material;

[0034] The catechol copolymer is modified by using N,N-dimethylformamide and isophorone diisocyanate under an oil bath condition of 60° C. to obtain an underwater adhesive.

[0035] Preferably, the mass volume ratio of the catechol copolymer, N,N-dimethylformamide and isophorone diisocyanate is 23-25:90-100:80-90 in mg / μL.

[0036] Preferably, the modification treatment is carried out in an oil bath at 60° C. for 4 hours.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The present invention prepares an underwater self-curing and strongly adhesive catechol copolymer underwater adhesive. The raw materials are readily available and have a large amount of catechol structures. After reacting with water, more polar groups (such as carbamate, etc.) are generated, making the underwater adhesive have high adhesion to many substances. In addition, the prepared underwater adhesive can be directly cured underwater, has stable adhesion performance and high adhesion strength, and has great potential in the fields of marine engineering, ship maintenance, etc.

[0039] During specific use, the adhesive undergoes solvent exchange with water underwater, and the isocyanate groups react with water to cross-link, thereby increasing the cohesive strength and introducing more hydroxyl groups to transform the adhesive into an elastomer with high adhesion strength. In addition, part of the liquid also penetrates into the gaps on the surface of the substrate, producing a mechanical locking effect after curing, further enhancing the adhesion strength. As the degree of reaction between isocyanate and water continues to increase, its adhesion strength also continues to increase. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a digital photo of the polymer P(DA-co-He) obtained after freeze-drying;

[0041] Figure 2 Digital photos of the prepared underwater adhesive;

[0042] Figure 3 is the H NMR spectrum of DA-Bn monomer;

[0043] Figure 4 is the H NMR spectrum of PDA-Bn polymer;

[0044] Figure 5 is the H NMR spectrum of polymer P(DA-co-He);

[0045] Figure 6 Schematic diagram of underwater bonding of steel using the prepared underwater adhesive;

[0046] Figure 7 This is a comparison chart of the adhesion strength of steel materials bonded underwater using the prepared underwater adhesive at different curing times. DETAILED DESCRIPTION

[0047] To further understand the content of the present invention, the present invention is described in detail in conjunction with the accompanying drawings and embodiments. The structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the content disclosed in the specification, so that people familiar with the technology can understand and read them. They are not used to limit the limitations of the implementation of the present invention and therefore have no technical significance. Any structural modifications, changes in proportional relationships, or adjustments in size should still fall within the scope of the technical content disclosed in the present invention without affecting the efficacy and objectives that can be achieved by the present invention. At the same time, terms such as "upper", "lower", "left", "right", and "middle" used in this specification are only for ease of description and are not used to limit the scope of implementation. Changes or adjustments in their relative relationships should also be considered as the scope of implementation of the present invention without substantially changing the technical content. It should be noted that the terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way are interchangeable where appropriate for the embodiments of the present application described herein.

[0048] Most commercial adhesives struggle to meet the requirements of underwater operation, and achieving strong interfacial bridging in aqueous media is more difficult than in air. When exposed to an aqueous environment, most materials form a hydration layer on their surface, hindering molecular-level bridging between the adhesive and the substrate. Utilizing catechol structures could address these challenges, but dopamine is expensive, necessitating a catechol-containing monomer that can replace dopamine. To this end, the present invention provides the following catechol copolymers.

[0049] A catechol copolymer having the structure shown in the following formula:

[0050] .

[0051] Furthermore, the catechol copolymer is prepared by the following chemical formula:

[0052] .

[0053] With respect to the above-disclosed porphyrin-based covalent organic framework material with dual silver ion loading, the present invention further provides the following preparation examples.

[0054] Example 1 (Preparation of catechol copolymer)

[0055] S1. Preparation of DPE-Bn monomer

[0056] 4.83 g of 3,4-dihydroxyphenylethanol, 13.0 g of potassium carbonate, and 10.7 g of benzyl bromide were placed in a 250 mL three-necked flask, and then 100 mL of acetonitrile was added. Nitrogen was introduced for protection, and the reaction was carried out at a constant temperature of 50°C in an oil bath. After the reaction was completed, the mixture was filtered, concentrated by rotary evaporation at 40°C, extracted with ethyl acetate: water = 1:1, dried over anhydrous magnesium sulfate, and concentrated by rotary evaporation at 35°C to obtain DPE-Bn monomer.

[0057] S2. Preparation of DA-Bn Monomer

[0058] 4.19 g of DPE-Bn monomer was placed in a 50 mL three-necked flask, and then 5.22 mL of triethylamine and 20 mL of dichloromethane were added. Subsequently, 1.53 mL of acryloyl chloride was added in an ice-water bath to react. After the reaction was completed, the solution was concentrated by rotary evaporation at room temperature at 25°C and purified by column chromatography with n-hexane: ethyl acetate = 5:1 to obtain DA-Bn monomer.

[0059] S3. Preparation of PDA-Bn Polymer

[0060] 776 mg of DA-Bn monomer, 200 mg of 5-hexen-1-ol, and 9.76 mg of azobisisobutyronitrile were placed in a 50 mL three-necked flask, and then 2 mL of N,N-dimethylformamide was added. The mixture was reacted in an oil bath at 80°C for 2 h. After the reaction, the reactants were precipitated in methanol to obtain PDA-Bn polymer.

[0061] S4. Preparation of catechol copolymer

[0062] 1 g of PDA-Bn polymer was placed in a 50 mL three-necked flask, and then 10 mL of dichloromethane was added, followed by 1 mL of trimethylsilyl iodide and reaction for 12 h in an ice-water bath. After the reaction, 10.0 mL of 1 M hydrochloric acid solution was added to precipitate the reactant, and then the precipitate was dissolved with 50 mL of N,N-dimethylformamide, extracted with N,N-dimethylformamide: n-hexane = 1:1, washed with saturated brine, and freeze-dried at -50°C for 24 h to obtain the polymer P(DA-co-He), i.e., catechol copolymer.

[0063] In this embodiment:

[0064] pass Figure 3 The H NMR spectrum shown proves the successful preparation of DA-Bn monomer;

[0065] pass Figure 4 The H NMR spectrum shown here proves that the DA-Bn monomer and 5-hexen-1-ol have undergone polymerization, that is, the PDA-Bn copolymer has been successfully prepared;

[0066] pass Figure 5The H NMR spectrum shown in the figure shows that: the benzyl peaks at 7.25 ppm and 4.9 ppm disappear, proving that the polymer is successfully deprotected, and the hydroxyl peak of catechol at 8.7 ppm is generated, proving that the polymer P (DA-co-He) is successfully prepared; and the prepared polymer P (DA-co-He) is washed with saturated brine, first frozen at -20 ° C for 24 hours, and then transferred to a freeze dryer, and freeze-dried at -50 ° C for 24 hours to obtain the following Figure 1 Actual photos shown.

[0067] Example 2 (Preparation of underwater adhesive)

[0068] 224 mg of the polymer P(DA-co-He) prepared in Example 1 was placed in a three-necked flask, and then 976 μL of N,N-dimethylformamide and 840 μL of isophorone diisocyanate were added. The mixture was reacted in an oil bath at 60°C for 4 h to obtain the following: Figure 2 Underwater adhesive shown.

[0069] For the underwater adhesive prepared in this embodiment, Figure 6 As shown, two pieces of 80mm×25mm×2mm steel were polished smooth and placed in an underwater environment. The underwater adhesive prepared in this embodiment was applied to a 25mm×25mm bonding area on the surface of the steel and then underwater bonding was performed.

[0070] Five control groups of steel materials bonded under the same treatment were set up, and the lap shear strength of the steel bonded joints was tested after curing for 3h, 6h, 24h, 48h and 72h respectively. The specific test results are as follows: Figure 7 As shown, the underwater adhesive prepared in this embodiment has excellent adhesion to metal materials underwater.

[0071] In summary, the present invention selects 3,4-dihydroxyphenylethanol as the raw material for preparing the underwater adhesive. It not only has a catechol structure but also costs much less than dopamine, effectively reducing the production cost of the underwater adhesive. Furthermore, the introduction of isophorone diisocyanate into the polymer enables the adhesive to automatically cure underwater, reducing the difficulty of underwater bonding. 5-Hexen-1-ol appropriately increases the soft segment of the polymer, allowing sufficient space for segment migration, thereby enhancing the adhesive and cohesive strength of the underwater adhesive.

[0072] Note that the above are only preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments and may include many other equivalent embodiments without departing from the concept of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. A catechol copolymer, characterized in that It has the following structure: 。 2. The method for preparing a catechol copolymer according to claim 1, wherein include: S1. DPE-Bn monomer was prepared from 3,4-dihydroxyphenylethanol, potassium carbonate, benzyl bromide, and acetonitrile under nitrogen protection and an oil bath at 50°C. S2. After mixing DPE-Bn monomer, triethylamine and dichloromethane, acryloyl chloride was added under ice-water bath conditions, and the reaction was completed to obtain DA-Bn monomer; S3. A DA-Bn monomer, 5-hexen-1-ol, azobisisobutyronitrile and N,N-dimethylformamide were polymerized in an oil bath at 80°C. After the reaction, the reactants were precipitated in methanol to obtain a PDA-Bn polymer. S4. After mixing the PDA-Bn polymer with dichloromethane, trimethylsilyl iodide is added in an ice-water bath. After the reaction is completed, hydrochloric acid solution is added to precipitate the reactants. The precipitate is then dissolved with N,N-dimethylformamide to obtain the polymer P(DA-co-He), i.e., a catechol copolymer.

3. The method for preparing a catechol copolymer according to claim 2, wherein In the step S1: Mix 3,4-dihydroxyphenylethanol, potassium carbonate, benzyl bromide, and acetonitrile in a mass volume ratio of 4-5:11-14:10-12:100 g / mL and react under nitrogen protection in an oil bath at 50°C for 5 h; After the reaction, the mixture was filtered, concentrated by rotary evaporation at 40°C, extracted with ethyl acetate: water = 1:1, dried over anhydrous magnesium sulfate, and concentrated by rotary evaporation at 35°C to obtain DPE-Bn monomer.

4. The method for preparing a catechol copolymer according to claim 3, wherein In the step S2: The mass volume ratio of the DPE-Bn monomer, triethylamine, dichloromethane and acryloyl chloride is 4-5:5-6:20:1-2 g / mL; The reaction was carried out under ice-water bath conditions for 12 h. After the reaction was completed, the DA-Bn monomer was obtained by rotary evaporation and purification at room temperature at 25°C and column chromatography using n-hexane:ethyl acetate = 5:

1.

5. The method for preparing the catechol copolymer according to claim 4, wherein In the step S3: The mass volume ratio of the DA-Bn monomer, 5-hexen-1 alcohol, azobisisobutyronitrile and N,N-dimethylformamide is 700-800:200:9-10:2 in mg / mL; The polymerization reaction was carried out in an oil bath at 80° C. for 2 h.

6. The method for preparing the catechol copolymer according to claim 5, wherein: In the step S4: The mass volume ratio of the PDA-Bn polymer, dichloromethane and trimethylsilyl iodide is 1:10:1 g / mL; The reaction was carried out under ice-water bath conditions for 12 hours. After the reaction was completed, hydrochloric acid solution was added to precipitate the reactants, and then the precipitate was dissolved with N,N-dimethylformamide, extracted with N,N-dimethylformamide:n-hexane = 1:1, washed with saturated brine, and freeze-dried at -50°C for 24 hours to obtain a polymer P(DA-co-He), i.e., a catechol copolymer.

7. Use of the catechol copolymer as shown in claim 1 or the catechol copolymer prepared by the preparation method according to any one of claims 2 to 6 in the preparation of underwater adhesives.

8. A method for preparing an underwater adhesive, characterized in that: The steps include: Take the catechol copolymer as shown in right 1 or the catechol copolymer prepared by the preparation method according to any one of claims 2 to 6 as a raw material; The catechol copolymer is modified by using N,N-dimethylformamide and isophorone diisocyanate under an oil bath condition of 60° C. to obtain an underwater adhesive.

9. The method for preparing the underwater adhesive according to claim 8, characterized in that: The mass volume ratio of the catechol copolymer, N,N-dimethylformamide and isophorone diisocyanate is 23-25 ​​mg / μL: 90-100: 80-90; The modification treatment was carried out in an oil bath at 60° C. for 4 h.

10. An underwater adhesive prepared by the preparation method according to claim 8 or 9.

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