MOFs-containing epoxy resin curing agent and preparation method and application thereof

Abstract

The invention provides an epoxy resin curing agent containing MOFs as well as a preparation method and application thereof, and the preparation method comprises the following steps: S1, dissolving an organic ligand in an N, N-dimethylformamide (DMF) solution, and dropwise adding a sodium hydroxide aqueous solution into the organic ligand solution to obtain disodium salt; s2, dissolving the disodium salt precipitate obtained in the step (1) in distilled water; slowly dropwise adding 10mL of deionized water into manganese chloride, stirring and dissolving, adding a disodium salt aqueous solution, mixing, and carrying out vacuum drying to obtain a metal organic framework material Mn-NPA; s3, heating the Mn-NPA, and carrying out vacuum drying and activation on the Mn-NPA; s4, Mn-NPA and an imidazole compound are mixed for a load reaction; and S5, filtering and drying the reacted mixture to obtain the epoxy resin curing agent containing MOFs. According to the epoxy resin curing agent containing MOFs, an epoxy resin coating can be prepared into a single component, and the epoxy resin curing agent can be used once a cover is opened and is convenient to use and easy to construct.

Description

Technical Field

[0001] This invention relates to the field of polymer grouting materials, and more specifically to a method for preparing an epoxy resin curing agent containing MOFs. Background Technology

[0002] Epoxy resins are widely used in high-tech fields such as aerospace, electronic packaging, and energy equipment due to their high strength, high modulus, chemical resistance, excellent adhesion, and superior thermal and dimensional stability. Before curing, epoxy resins are liquid or have a low softening point and require a curing agent to become usable.

[0003] Commonly available curing agents are mainly room-temperature curing amines and acid anhydrides. When using them, the epoxy resin and curing agent must be mixed evenly on-site according to the specified ratio. This process is cumbersome, and the prepared product must be used up within a short period of time and cannot be stored for a long time. Some amine curing agents also release toxic gases that are easily volatilized, which can endanger the health of operators. Summary of the Invention

[0004] This invention provides an epoxy resin curing agent containing MOFs that has low activity at low temperatures and is stable during storage, along with its preparation method and application.

[0005] The technical solution of this invention is: a method for preparing an epoxy resin curing agent containing MOFs, comprising the following steps: S1, weigh out the organic ligand and dissolve it in N,N-dimethylformamide (DMF) solution. Sodium hydroxide was dissolved in distilled water, and sodium hydroxide aqueous solution was added dropwise to the organic ligand solution. The solution was stirred at room temperature for half an hour, filtered and dried to obtain disodium salt. S2 Dissolve the disodium salt precipitate obtained in step (1) in distilled water; weigh a certain amount of manganese chloride, slowly add 10 mL of deionized water and stir to dissolve, add the disodium salt aqueous solution obtained in step (1), mix, stir at room temperature for half an hour, centrifuge, and vacuum dry to obtain metal-organic framework (MOF) material Mn-NPA. S3, the Mn-NPA is heated to 70°C and dried and activated under vacuum (vacuum degree -0.8MPa); S4, the Mn-NPA is mixed with an ethanol solution of an imidazole compound to carry out a loading reaction; S5. The mixture after the loading reaction is completed is filtered, dried and processed to obtain epoxy resin curing agent powder containing MOFs.

[0006] Furthermore, the aforementioned organic ligand is nitroterephthalic acid.

[0007] Furthermore, the aforementioned imidazole compounds are 2-methylimidazole or 3,5-dimethylpyrazole.

[0008] Furthermore, the molar ratio of the above-mentioned nitroterephthalic acid: DMF: sodium hydroxide: manganese chloride is 1:13:2:1.

[0009] Furthermore, the heating temperature in step S3 above is 70°C, and the vacuum degree is -0.8 MPa.

[0010] Furthermore, the mass ratio between the above-mentioned Mn-NPA and imidazole compounds is 1 to 7:10.

[0011] An epoxy resin curing agent obtained by any of the above preparation methods.

[0012] The above-mentioned epoxy resin curing agent is used in epoxy resin, and the mass ratio between the epoxy resin curing agent and epoxy resin is 1:9.

[0013] The MOF-containing epoxy resin curing agent of this invention can prepare epoxy resin coatings into a single component, ready to use upon opening, convenient to apply, easy to apply, and less prone to curing, thus minimizing waste. After the epoxy resin coating is applied, the MOF material pores are activated at a set temperature, causing the pores to release curing agent molecules, which then react with the epoxy resin to cure. Attached Figure Description

[0014] Figure 1 The image shows the DSC curve of the cured epoxy resin curing agent containing MOFs mixed with epoxy resin in Example 6 of this invention. Figure 2 The TG curves of Mn-NPA and MOF-containing epoxy resin curing agent in Example 6 of this invention are shown. Figure 3 The image shown is the XRD pattern of Mn-NPA in Embodiment 6 of the present invention. Figure 4 The image shows the infrared test results of Mn-NPA and MOF-containing epoxy resin curing agent in Example 6 of this invention. Detailed Implementation

[0015] The present invention will be further described below with reference to specific embodiments: Example

[0016] The preparation method of epoxy resin curing agent includes the following steps: (1) Dissolve 10.55g of nitroterephthalic acid in 50mL of N,N-dimethylformamide (DMF) and sonicate for 15min; dissolve 4g of sodium hydroxide in 10mL of distilled water; slowly add the aqueous solution of sodium hydroxide to the DMF solution of nitroterephthalic acid, stir and react at room temperature for half an hour, and filter to obtain a white precipitate of disodium salt of organic ligand.

[0017] (2) Dissolve the disodium salt precipitate obtained in step (1) in 20 mL of distilled water; weigh 6.29 g of manganese chloride, slowly add 10 mL of deionized water and stir to dissolve, add the disodium salt aqueous solution obtained in step (1), stir and mix at room temperature for half an hour, centrifuge, wash with anhydrous ethanol to obtain metal-organic framework (MOF) material Mn-NPA.

[0018] (3) Activate Mn-NPA by heating it to 70℃ and drying it under vacuum (vacuum degree -0.8MPa) for 24 hours; (4) Dissolve 0.1 g of 2-methylimidazole in 100 mL of anhydrous ethanol, then add 1.0 g of Mn-NPA powder obtained in step (3), and stir at a constant speed for 48 h. After the reaction is completed, evaporate by rotary evaporation at 60 °C and then vacuum dry to obtain a solid powder, which is the epoxy resin curing agent containing MOFs. Example

[0019] The preparation method of epoxy resin curing agent includes the following steps: (1) Dissolve 10.55g of nitroterephthalic acid in 50mL of N,N-dimethylformamide (DMF) and sonicate for 15min; dissolve 4g of sodium hydroxide in 10mL of distilled water; slowly add the aqueous solution of sodium hydroxide to the DMF solution of nitroterephthalic acid, stir and react at room temperature for half an hour, and filter to obtain a white precipitate of disodium salt of organic ligand.

[0020] (2) Dissolve the disodium salt precipitate obtained in step (1) in 20 mL of distilled water; weigh 6.29 g of manganese chloride, slowly add 10 mL of deionized water and stir to dissolve, add the disodium salt aqueous solution obtained in step (1), stir and mix at room temperature for half an hour, centrifuge, wash with anhydrous ethanol to obtain metal-organic framework (MOF) material Mn-NPA.

[0021] (3) Activate Mn-NPA by heating it to 70℃ and drying it under vacuum (vacuum degree -0.8MPa) for 24 hours; (4) Dissolve 0.2 g of 2-methylimidazole in 100 mL of anhydrous ethanol, then add 1.0 g of Mn-NPA powder obtained in step (3), and stir at a constant speed for 48 h. After the reaction is completed, evaporate by rotary evaporation at 60 °C and then vacuum dry to obtain a solid powder, which is the epoxy resin curing agent containing MOFs. Example

[0022] The preparation method of epoxy resin curing agent includes the following steps: (1) Dissolve 10.55g of nitroterephthalic acid in 50mL of N,N-dimethylformamide (DMF) and sonicate for 15min; dissolve 4g of sodium hydroxide in 10mL of distilled water; slowly add the aqueous solution of sodium hydroxide to the DMF solution of nitroterephthalic acid, stir and react at room temperature for half an hour, and filter to obtain a white precipitate of disodium salt of organic ligand.

[0023] (2) Dissolve the disodium salt precipitate obtained in step (1) in 20 mL of distilled water; weigh 6.29 g of manganese chloride, slowly add 10 mL of deionized water and stir to dissolve, add the disodium salt aqueous solution obtained in step (1), stir and mix at room temperature for half an hour, centrifuge, wash with anhydrous ethanol to obtain metal-organic framework (MOF) material Mn-NPA.

[0024] (3) Activate Mn-NPA by heating it to 70℃ and drying it under vacuum (vacuum degree -0.8MPa) for 24 hours; (4) Dissolve 0.3g of 2-methylimidazole in 100mL of anhydrous ethanol, then add 1.0g of Mn-NPA powder obtained in step (3), and stir at a constant speed for 48h. After the reaction is completed, the solid powder is obtained by rotary evaporation at 60℃ and vacuum drying, which is the epoxy resin curing agent containing MOFs. Example

[0025] The preparation method of epoxy resin curing agent includes the following steps: (1) Dissolve 10.55g of nitroterephthalic acid in 50mL of N,N-dimethylformamide (DMF) and sonicate for 15min; dissolve 4g of sodium hydroxide in 10mL of distilled water; slowly add the aqueous solution of sodium hydroxide to the DMF solution of nitroterephthalic acid, stir and react at room temperature for half an hour, and filter to obtain a white precipitate of disodium salt of organic ligand.

[0026] (2) Dissolve the disodium salt precipitate obtained in step (1) in 20 mL of distilled water; weigh 6.29 g of manganese chloride, slowly add 10 mL of deionized water and stir to dissolve, add the disodium salt aqueous solution obtained in step (1), stir and mix at room temperature for half an hour, centrifuge, wash with anhydrous ethanol to obtain metal-organic framework (MOF) material Mn-NPA.

[0027] (3) Activate Mn-NPA by heating it to 70℃ and drying it under vacuum (vacuum degree -0.8MPa) for 24 hours; (4) Dissolve 0.4 g of 2-methylimidazole in 100 mL of anhydrous ethanol, then add 1.0 g of Mn-NPA powder obtained in step (3), and stir at a constant speed for 48 h. After the reaction is completed, evaporate by rotary evaporation at 60 °C and then vacuum dry to obtain a solid powder, which is the epoxy resin curing agent containing MOFs. Example

[0028] The preparation method of epoxy resin curing agent includes the following steps: (1) Dissolve 10.55g of nitroterephthalic acid in 50mL of N,N-dimethylformamide (DMF) and sonicate for 15min; dissolve 4g of sodium hydroxide in 10mL of distilled water; slowly add the aqueous solution of sodium hydroxide to the DMF solution of nitroterephthalic acid, stir and react at room temperature for half an hour, and filter to obtain a white precipitate of disodium salt of organic ligand.

[0029] (2) Dissolve the disodium salt precipitate obtained in step (1) in 20 mL of distilled water; weigh 6.29 g of manganese chloride, slowly add 10 mL of deionized water and stir to dissolve, add the disodium salt aqueous solution obtained in step (1), stir and mix at room temperature for half an hour, centrifuge, wash with anhydrous ethanol, and vacuum dry at 70 °C for 24 h to obtain metal-organic framework (MOF) material Mn-NPA.

[0030] (3) Activate Mn-NPA by heating it to 70℃ and drying it under vacuum (vacuum degree -0.8MPa) for 24 hours; (4) Dissolve 0.5g of 2-methylimidazole in 100mL of anhydrous ethanol, then add 1.0g of Mn-NPA powder obtained in step (3), and stir at a constant speed for 48h. After the reaction is completed, evaporate by rotary evaporation at 60℃ and then vacuum dry to obtain a solid powder, which is the epoxy resin curing agent containing MOFs. Example

[0031] The preparation method of epoxy resin curing agent includes the following steps: (1) Dissolve 10.55g of nitroterephthalic acid in 50mL of N,N-dimethylformamide (DMF) and sonicate for 15min; dissolve 4g of sodium hydroxide in 10mL of distilled water; slowly add the aqueous solution of sodium hydroxide to the DMF solution of nitroterephthalic acid, stir and react at room temperature for half an hour, and filter to obtain a white precipitate of disodium salt of organic ligand.

[0032] (2) Dissolve the disodium salt precipitate obtained in step (1) in 20 mL of distilled water; weigh 6.29 g of manganese chloride, slowly add 10 mL of deionized water and stir to dissolve, add the disodium salt aqueous solution obtained in step (1), stir and mix at room temperature for half an hour, centrifuge, wash with anhydrous ethanol to obtain metal-organic framework (MOF) material Mn-NPA.

[0033] (3) Activate Mn-NPA by heating it to 70℃ and drying it under vacuum (vacuum degree -0.8MPa) for 24 hours; (4) Dissolve 0.6 g of 2-methylimidazole in 100 mL of anhydrous ethanol, then add 1.0 g of Mn-NPA powder obtained in step (3), and stir at a constant speed for 48 h. After the reaction is completed, the solid powder is obtained by rotary evaporation at 60 °C and vacuum drying, which is the epoxy resin curing agent containing MOFs. Example

[0034] The preparation method of epoxy resin curing agent includes the following steps: (1) Dissolve 10.55g of nitroterephthalic acid in 50mL of N,N-dimethylformamide (DMF) and sonicate for 15min; dissolve 4g of sodium hydroxide in 10mL of distilled water; slowly add the aqueous solution of sodium hydroxide to the DMF solution of nitroterephthalic acid, stir and react at room temperature for half an hour, and filter to obtain a white precipitate of disodium salt of organic ligand.

[0035] (2) Dissolve the disodium salt precipitate obtained in step (1) in 20 mL of distilled water; weigh 6.29 g of manganese chloride, slowly add 10 mL of deionized water and stir to dissolve, add the disodium salt aqueous solution obtained in step (1), stir and mix at room temperature for half an hour, centrifuge, wash with anhydrous ethanol to obtain metal-organic framework (MOF) material Mn-NPA.

[0036] (3) Activate Mn-NPA by heating it to 70℃ and drying it under vacuum (vacuum degree -0.8MPa) for 24 hours; (4) Dissolve 0.7g of 2-methylimidazole in 100mL of anhydrous ethanol, then add 1.0g of Mn-NPA powder obtained in step (3), and stir at a constant speed for 48h. After the reaction is completed, evaporate by rotary evaporation at 60℃ and then vacuum dry to obtain a solid powder, which is the epoxy resin curing agent containing MOFs. Example

[0037] The preparation method of epoxy resin curing agent includes the following steps: (1) Dissolve 10.55g of nitroterephthalic acid in 50mL of N,N-dimethylformamide (DMF) and sonicate for 15min; dissolve 4g of sodium hydroxide in 10mL of distilled water; slowly add the sodium hydroxide aqueous solution to the DMF solution of nitroterephthalic acid, stir and react at room temperature for half an hour, and filter to obtain the disodium salt precipitate of the organic ligand.

[0038] (2) Dissolve the disodium salt precipitate obtained in step (1) in 20 mL of distilled water; weigh 6.29 g of manganese chloride, slowly add 10 mL of deionized water and stir to dissolve, add the disodium salt aqueous solution obtained in step (1), stir and mix at room temperature for half an hour, centrifuge, wash with anhydrous ethanol to obtain metal-organic framework (MOF) material Mn-NPA.

[0039] (3) Activate Mn-NPA by heating it to 70℃ and drying it under vacuum (vacuum degree -0.8MPa) for 24 hours; (4) Dissolve 0.1 g of 3,5-dimethylpyrazole in 100 mL of anhydrous ethanol, then add 1.0 g of Mn-NPA powder prepared in step (3), and stir at a constant speed for 48 h. After the reaction is completed, the solid powder is obtained by rotary evaporation at 60 °C and vacuum drying, which is the epoxy resin curing agent containing MOFs. Example

[0040] The preparation method of epoxy resin curing agent includes the following steps: (1) Dissolve 10.55g of nitroterephthalic acid in 50mL of N,N-dimethylformamide (DMF) and sonicate for 15min; dissolve 4g of sodium hydroxide in 10mL of distilled water; slowly add the sodium hydroxide aqueous solution to the DMF solution of nitroterephthalic acid, stir and react at room temperature for half an hour, and filter to obtain the disodium salt precipitate of the organic ligand.

[0041] (2) Dissolve the disodium salt precipitate obtained in step (1) in 20 mL of distilled water; weigh 6.29 g of manganese chloride, slowly add 10 mL of deionized water and stir to dissolve, add the disodium salt aqueous solution obtained in step (1), stir and mix at room temperature for half an hour, centrifuge, wash with anhydrous ethanol to obtain metal-organic framework (MOF) material Mn-NPA.

[0042] (3) Activate Mn-NPA by heating it to 70℃ and drying it under vacuum (vacuum degree -0.8MPa) for 24 hours; (4) Dissolve 0.2 g of 3,5-dimethylpyrazole in 100 mL of anhydrous ethanol, then add 1.0 g of Mn-NPA powder obtained in step (3), and stir at a constant speed for 48 h. After the reaction is completed, the solid powder is obtained by rotary evaporation at 60 °C and vacuum drying, which is the epoxy resin curing agent containing MOFs. Example

[0043] The preparation method of epoxy resin curing agent includes the following steps: (1) Dissolve 10.55g of nitroterephthalic acid in 50mL of N,N-dimethylformamide (DMF) and sonicate for 15min; dissolve 4g of sodium hydroxide in 10mL of distilled water; slowly add the sodium hydroxide aqueous solution to the DMF solution of nitroterephthalic acid, stir and react at room temperature for half an hour, and filter to obtain the disodium salt precipitate of the organic ligand.

[0044] (2) Dissolve the disodium salt precipitate obtained in step (1) in 20 mL of distilled water; weigh 6.29 g of manganese chloride, slowly add 10 mL of deionized water and stir to dissolve, add the disodium salt aqueous solution obtained in step (1), stir and mix at room temperature for half an hour, centrifuge, wash with anhydrous ethanol to obtain metal-organic framework (MOF) material Mn-NPA.

[0045] (3) Activate Mn-NPA by heating it to 70℃ and drying it under vacuum (vacuum degree -0.8MPa) for 24 hours; (4) Dissolve 0.3g of 3,5-dimethylpyrazole in 100mL of anhydrous ethanol, then add 1.0g of Mn-NPA powder prepared in step (3), and stir at a constant speed for 48h. After the reaction is completed, the solid powder is obtained by rotary evaporation at 60℃ and vacuum drying, which is the epoxy resin curing agent containing MOFs. Example

[0046] The preparation method of epoxy resin curing agent includes the following steps: (1) Dissolve 10.55g of nitroterephthalic acid in 50mL of N,N-dimethylformamide (DMF) and sonicate for 15min; dissolve 4g of sodium hydroxide in 10mL of distilled water; slowly add the sodium hydroxide aqueous solution to the DMF solution of nitroterephthalic acid, stir and react at room temperature for half an hour, and filter to obtain the disodium salt precipitate of the organic ligand.

[0047] (2) Dissolve the disodium salt precipitate obtained in step (1) in 20 mL of distilled water; weigh 6.29 g of manganese chloride, slowly add 10 mL of deionized water and stir to dissolve, add the disodium salt aqueous solution obtained in step (1), stir and mix at room temperature for half an hour, centrifuge, wash with anhydrous ethanol to obtain metal-organic framework (MOF) material Mn-NPA.

[0048] (3) Activate Mn-NPA by heating it to 70℃ and drying it under vacuum (vacuum degree -0.8MPa) for 24 hours; (4) Dissolve 0.4 g of 3,5-dimethylpyrazole in 100 mL of anhydrous ethanol, then add 1.0 g of Mn-NPA powder obtained in step (3), and stir at a constant speed for 48 h. After the reaction is completed, evaporate by rotary evaporation at 60 °C and then vacuum dry to obtain a solid powder, which is the epoxy resin curing agent containing MOFs. Example

[0049] The preparation method of epoxy resin curing agent includes the following steps: (1) Dissolve 10.55g of nitroterephthalic acid in 50mL of N,N-dimethylformamide (DMF) and sonicate for 15min; dissolve 4g of sodium hydroxide in 10mL of distilled water; slowly add the sodium hydroxide aqueous solution to the DMF solution of nitroterephthalic acid, stir and react at room temperature for half an hour, and filter to obtain the disodium salt precipitate of the organic ligand.

[0050] (2) Dissolve the disodium salt precipitate obtained in step (1) in 20 mL of distilled water; weigh 6.29 g of manganese chloride, slowly add 10 mL of deionized water and stir to dissolve, add the disodium salt aqueous solution obtained in step (1), stir and mix at room temperature for half an hour, centrifuge, wash with anhydrous ethanol to obtain metal-organic framework (MOF) material Mn-NPA.

[0051] (3) Activate Mn-NPA by heating it to 70℃ and drying it under vacuum (vacuum degree -0.8MPa) for 24 hours; (4) Dissolve 0.5g of 3,5-dimethylpyrazole in 100mL of anhydrous ethanol, then add 1.0g of Mn-NPA powder obtained in step (3), and stir at a constant speed for 48h. After the reaction is completed, the solid powder is obtained by rotary evaporation at 60℃ and vacuum drying, which is the epoxy resin curing agent containing MOFs. Example

[0052] The preparation method of epoxy resin curing agent includes the following steps: (1) Dissolve 10.55g of nitroterephthalic acid in 50mL of N,N-dimethylformamide (DMF) and sonicate for 15min; dissolve 4g of sodium hydroxide in 10mL of distilled water; slowly add the sodium hydroxide aqueous solution to the DMF solution of nitroterephthalic acid, stir and react at room temperature for half an hour, and filter to obtain the disodium salt precipitate of the organic ligand.

[0053] (2) Dissolve the disodium salt precipitate obtained in step (1) in 20 mL of distilled water; weigh 6.29 g of manganese chloride, slowly add 10 mL of deionized water and stir to dissolve, add the disodium salt aqueous solution obtained in step (1), stir and mix at room temperature for half an hour, centrifuge, wash with anhydrous ethanol to obtain metal-organic framework (MOF) material Mn-NPA.

[0054] (3) Activate Mn-NPA by heating it to 70℃ and drying it under vacuum (vacuum degree -0.8MPa) for 24 hours; (4) Dissolve 0.6 g of 3,5-dimethylpyrazole in 100 mL of anhydrous ethanol, then add 1.0 g of Mn-NPA powder obtained in step (3), and stir at a constant speed for 48 h. After the reaction is completed, the solid powder is obtained by rotary evaporation at 60 °C and vacuum drying, which is the epoxy resin curing agent containing MOFs. Example

[0055] The preparation method of epoxy resin curing agent includes the following steps: (1) Dissolve 10.55g of nitroterephthalic acid in 50mL of N,N-dimethylformamide (DMF) and sonicate for 15min; dissolve 4g of sodium hydroxide in 10mL of distilled water; slowly add the sodium hydroxide aqueous solution to the DMF solution of nitroterephthalic acid, stir and react at room temperature for half an hour, and filter to obtain the disodium salt precipitate of the organic ligand.

[0056] (2) Dissolve the disodium salt precipitate obtained in step (1) in 20 mL of distilled water; weigh 6.29 g of manganese chloride, slowly add 10 mL of deionized water and stir to dissolve, add the disodium salt aqueous solution obtained in step (1), stir and mix at room temperature for half an hour, centrifuge, wash with anhydrous ethanol to obtain metal-organic framework (MOF) material Mn-NPA.

[0057] (3) Activate Mn-NPA by heating it to 70℃ and drying it under vacuum (vacuum degree -0.8MPa) for 24 hours; (4) Dissolve 0.7g of 3,5-dimethylpyrazole in 100mL of anhydrous ethanol, then add 1.0g of Mn-NPA powder obtained in step (3), and stir at a constant speed for 48h. After the reaction is completed, the solid powder is obtained by rotary evaporation at 60℃ and vacuum drying, which is the epoxy resin curing agent containing MOFs.

[0058] (1) Weigh 1g of 2-methylimidazole to obtain epoxy resin curing agent; (2) Mix 2-methylimidazole or 3,5-dimethylpyrazole with epoxy resin in a mass ratio of 1:9, at a stirring speed of 900 r / min and a stirring time of 30 min.

[0059] The epoxy resin curing agent prepared in Example 1 was mixed with epoxy resin at a mass ratio of 1:9, a stirring speed of 900 r / min, and a stirring time of 30 min.

[0060] The epoxy resin curing agent prepared in Example 2 was mixed with epoxy resin at a mass ratio of 1:9, a stirring speed of 900 r / min, and a stirring time of 30 min.

[0061] The epoxy resin curing agent prepared in Example 3 was mixed with epoxy resin at a mass ratio of 1:9, a stirring speed of 900 r / min, and a stirring time of 30 min.

[0062] The epoxy resin curing agent prepared in Example 4 was mixed with epoxy resin at a mass ratio of 1:9, a stirring speed of 900 r / min, and a stirring time of 30 min.

[0063] The epoxy resin curing agent prepared in Example 5 was mixed with epoxy resin at a mass ratio of 1:9, a stirring speed of 900 r / min, and a stirring time of 30 min.

[0064] The epoxy resin curing agent prepared in Example 6 was mixed with epoxy resin at a mass ratio of 1:9, a stirring speed of 900 r / min, and a stirring time of 30 min.

[0065] Figure 1 The example shown is the curing DSC curve of the epoxy resin curing agent containing MOFs mixed with epoxy resin.

[0066] The epoxy resin curing agent prepared in Example 7 was mixed with epoxy resin at a mass ratio of 1:9, a stirring speed of 900 r / min, and a stirring time of 30 min.

[0067] The epoxy resin curing agent prepared in Example 8 was mixed with epoxy resin at a mass ratio of 1:9, a stirring speed of 900 r / min, and a stirring time of 30 min.

[0068] The epoxy resin curing agent prepared in Example 9 was mixed with epoxy resin at a mass ratio of 1:9, a stirring speed of 900 r / min, and a stirring time of 30 min.

[0069] The epoxy resin curing agent prepared in Example 10 was mixed with epoxy resin at a mass ratio of 1:9, a stirring speed of 900 r / min, and a stirring time of 30 min.

[0070] The epoxy resin curing agent prepared in Example 11 was mixed with epoxy resin at a mass ratio of 1:9, a stirring speed of 900 r / min, and a stirring time of 30 min.

[0071] The epoxy resin curing agent prepared in Example 12 was mixed with epoxy resin at a mass ratio of 1:9, the stirring speed was 900 r / min, and the stirring time was 30 min.

[0072] The epoxy resin curing agent prepared in Example 13 was mixed with epoxy resin at a mass ratio of 1:9, a stirring speed of 900 r / min, and a stirring time of 30 min.

[0073] The epoxy resin curing agent prepared in Example 14 was mixed with epoxy resin at a mass ratio of 1:9, a stirring speed of 900 r / min, and a stirring time of 30 min.

[0074] The epoxy resin curing systems of Application Examples 1-14 and Comparative Example 1 were placed in constant temperature spaces with different temperatures. The curing time of the two systems was compared in Table 1. It can be determined that the activity of the curing agent of the present invention at low temperatures is much lower than that of pure imidazole compounds, and the storage stability is significantly extended.

[0075] Table 1

[0076] Figure 2 The TG curves of Mn-NPA and MOF-containing epoxy resin curing agents show that the decomposition temperature of Mn-NPA is 350℃, indicating good thermal stability. Compared with pure Mn-NPA, the curing agent 2MI@Mn-NPA experiences a 35% mass loss before 350℃, indicating that 2MI@Mn-NPA begins to release 2MI molecules at 170℃. The curing agent 2MI@Mn-NPA was successfully prepared, exhibiting good thermal stability, and the 2MI molecule loading rate is as high as 35%.

[0077] Figure 3 The image shows the XRD pattern of Mn-NPA, indicating that the metal Mn ions have coordinated with the ligand NPA to form a metal-organic framework structure material with good crystallinity.

[0078] Figure 4 The range of 800–750 cm⁻¹ corresponds to the out-of-plane bending vibration of the aromatic ring (benzene ring) CH₄. Mn-NPA exhibits vibrations at 1500 cm⁻¹. -1 There is a broad peak with strong absorption, which is attributed to the stretching vibration peak of COO-. It has undergone a significant red shift relative to NPA, indicating that the metal ion has coordinated with the ligand. From the above, it can be concluded that Mn-NPA was successfully prepared.

[0079] Comparing the infrared spectra of 2MI@Mn-NPA and Mn-NPA in the spectrum, 2MI@Mn-NPA has a 1562 cm⁻¹. -1 The characteristic peak of COO- stretching vibration at the point of origin also shows a slight redshift relative to Mn-NPA, but other characteristic absorption peaks are not significantly different, indicating that a very small amount of surface metal may coordinate with 2MI, but the main structure of the metal-organic framework surface has not changed significantly.

Claims

1. A method for preparing an epoxy resin curing agent containing MOFs, characterized in that, Includes the following steps: S1, weigh out the organic ligand and dissolve it in N,N-dimethylformamide (DMF) solution. Sodium hydroxide was dissolved in distilled water, and sodium hydroxide aqueous solution was added dropwise to the organic ligand solution. The mixture was stirred at room temperature for half an hour, filtered, and dried to obtain disodium salt. S2, dissolve the disodium salt precipitate obtained in step (1) in distilled water; weigh a certain amount of manganese chloride, slowly add 10 mL of deionized water and stir to dissolve, add the disodium salt aqueous solution obtained in step (1), mix, stir at room temperature for half an hour, centrifuge, and vacuum dry to obtain metal-organic framework (MOFs) Mn-NPA. S3, the Mn-NPA is activated by vacuum drying under heating; S4, the Mn-NPA is mixed with an ethanol solution of an imidazole compound to carry out a loading reaction; S5. After the loading reaction is completed, the mixture is filtered, dried and processed to obtain epoxy resin curing agent powder containing MOFs.

2. The preparation method according to claim 1, characterized in that, The organic ligand is nitroterephthalic acid.

3. The preparation method according to claim 1 or 2, characterized in that, The imidazole compound is 2-methylimidazole or 3,5-dimethylpyrazole.

4. The preparation method according to claim 1 or 2, characterized in that, The molar ratio of nitroterephthalic acid: DMF: sodium hydroxide: manganese chloride is 1:13:2:

1.

5. The preparation method according to claim 1 or 2, characterized in that, The heating temperature in step S3 is 70°C, and the vacuum degree is -0.8 MPa.

6. The preparation method according to claim 1 or 2, characterized in that, The mass ratio of Mn-NPA to imidazole compounds is 1 to 7:

10.

7. An epoxy resin curing agent obtained by any one of the preparation methods in claims 1-5.

8. The application of the epoxy resin curing agent according to claim 6 in epoxy resin, characterized in that, The mass ratio between the epoxy resin curing agent and the epoxy resin is 1:9.

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