Vinyl covalent organic framework foam material, its preparation method and application in the field of thermal insulation
Patent Information
- Application Number
- CN202510515825.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-23
- Publication Date
- 2026-10-23
AI Technical Summary
[0006]本申请提供一种乙烯基共价有机框架泡沫的制备方法及其在隔热领域应用，旨在解决现有有机框架材料制备工艺复杂、难以成型的问题，并为高温隔热领域提供新的材料
[0019]本发明方法通过特定的反应单体和有机助剂，通过有机助剂法在180～200℃的高温条件下合成乙烯基共价有机框架泡沫COFs，一方面，该方法不同于传统合成方法对有机溶剂的需求，所选用的有机助剂在室温下为固态，沸点高，高温条件下不产生大量蒸汽，合成工艺简单；另一方面，该方法可获得一系列共价有机框架泡沫材料，材料具有一定的弹性及韧性，后加工方便，且本身即可成型，有利于工业大规模生产。
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Abstract
Description
Technical Field
[0001] This invention relates to the field of foam materials technology, specifically to a vinyl covalent organic framework foam material, its preparation method, and its application in the field of thermal insulation. Background Technology
[0002] Covalent organic frameworks (COFs) are a class of porous organic materials with microporous or mesoporous structures, typically composed of elements such as C, H, O, N, and B. COF materials are characterized by large pore size, high specific surface area, good stability, and high designability, and are widely used in fields such as gas storage and separation, catalysis, energy conversion and storage, sensors, and biomedicine.
[0003] Currently, the main methods for synthesizing COFs include solution condensation polymerization, interfacial polymerization, microwave-assisted synthesis, and solid-state synthesis. Traditional methods such as solution polymerization, microwave-assisted synthesis, and solvothermal synthesis of COFs require the addition of different amounts of organic solvents. The volatilization of organic solvents at high reaction temperatures generates high pressure, and the preparation process is complex, which is not conducive to large-scale industrial production. On the other hand, COF materials synthesized by traditional methods are mostly in powder form, which severely limits their application in the industrial field.
[0004] Organic additives have shown great advantages in the preparation of polymer materials such as polyester and polyamide. They can be injected into the reaction mold in fluid form to form foam materials with specific shapes. Furthermore, by varying the amount of organic additives added, a series of foam materials with different densities and porosities can be obtained, showing broad prospects in the field of thermal insulation.
[0005] Therefore, developing an organic auxiliary synthesis method for vinyl COFs is of great significance. Summary of the Invention
[0006] This application provides a method for preparing vinyl covalent organic framework foam and its application in the field of thermal insulation, aiming to solve the problems of complex preparation process and difficulty in molding of existing organic framework materials, and to provide new materials for the field of high temperature thermal insulation.
[0007] To achieve the above objectives, in a first aspect, the present invention provides a method for preparing a vinyl covalent organic framework foam material. Organic molecules A and B, and organic additives in a molar ratio of 1:(1-2):(10-60), are subjected to a polymerization reaction in a closed reactor, such as a high-temperature and high-pressure resistant Pyrex tube, a flame-sealed ampoule, or a high-pressure reactor lined with polytetrafluoroethylene, at atmospheric or negative pressure and heated to 180-200°C for 72-168 hours. Organic molecules A and B undergo polymerization, and the methyl groups in organic molecule A and the aldehyde groups in organic molecule B undergo polymerization to form carbon-carbon double bonds, yielding a crude product containing a vinyl covalent organic framework foam. The crude product is then purified to obtain the vinyl covalent organic framework foam material, wherein:
[0008] The organic molecule A is a pyridine or pyrazine containing at least two methyl functional groups; the organic molecule B is an aromatic compound containing two aldehyde functional groups; and the flux is a compound containing a carboxylic acid functional group.
[0009] As a further preferred embodiment of the present invention, the organic molecule A is a pyrazine containing 2 to 4 methyl functional groups or a pyridine containing 2 to 3 methyl functional groups; and / or, the organic molecule B is any one of benzene or a derivative thereof, biphenyl or a derivative thereof, naphthalene or a derivative thereof, pyridine or a derivative thereof, bipyridine or a derivative thereof, anthracene or a derivative thereof, pyrazine or a derivative thereof, or phenanthroline or a derivative thereof, containing two aldehyde functional groups. Wherein, 2 to 4 refers to 2, 3, or 4; 2 to 3 refers to 2 or 3.
[0010] As a further preferred embodiment of the present invention, the organic molecule A includes any one or a combination of two or more of 2,3,5,6-tetramethylpyrazine, 2,3,5-trimethylpyrazine, 2,3-dimethylpyrazine, 2,5-dimethylpyrazine, 2,6-dimethylpyridine, and 2,4,6-trimethylpyridine.
[0011] As a further preferred embodiment of the present invention, the organic molecule B includes terephthalaldehyde, biphenyl dicarboxaldehyde, pyromellitic terephthalaldehyde, 2,5-dihydroxy-1,4-benzaldehyde, 1,4-dialdehyde-2,5-divinylbenzene, 2,3-dihydroxyterephthalaldehyde, 2,5-dibromobenzene-1,4-dicarboxaldehyde, 2,5-diethoxy-1,4-terephthalaldehyde, 2,2'-bipyridine-5,5'-dicarboxaldehyde, 1,4-bis(4-aldehydephenyl)benzene, 2,5-dialdehydepyridine, 2,6-naphthalenedicarboxyl, 5-hydroxy-m-phenylenedialdehyde, and 1,10-phenanthroline. The following are any one or a combination of two or more of the following: lin-2,9-dicarboxaldehyde, 4-hydroxy-isophthalaldehyde, anthracene-9,10-dicarboxaldehyde, 2,2'-bipyridine-4,4'-dicarboxaldehyde, 3,3'-bipyridine-6,6'-dicarboxaldehyde, 9,10-bis(4-aldehydephenyl)anthracene, 3,6-dimethylterephthalaldehyde, pyridine-2,6-dicarboxaldehyde, 2-methoxy-4,6-dialdehydephenol, 2-nitroterephthalaldehyde, 2,5-dialdehydepyrazine, 2,3-hydroxy-1,4-dialdehydenaphthalene, and 4,4'-dihydroxy-3,3'-glyoxal biphenyl.
[0012] The organic additive of the present invention is used to promote the polymerization reaction between the methyl group in organic molecule A and the aldehyde group in organic molecule B to form a carbon-carbon double bond, thereby obtaining a vinyl covalent organic framework foam. As a further preferred embodiment of the present invention, the organic additive includes at least one selected from benzoic acid, 4-fluorobenzoic acid, acetic anhydride, acetic acid, and propionic acid. Preferably, the molar ratio of organic molecule A to the organic additive is 1:(20-40), which, within this range, helps to obtain a vinyl covalent organic framework foam.
[0013] As a further preferred embodiment of the present invention, the polymerization reaction time is 72 to 168 hours.
[0014] As a further preferred embodiment of the present invention, the pressure of the organic additive is normal pressure or negative pressure.
[0015] As a further preferred technical solution of the present invention, the purification process specifically includes: soaking the reaction product in DMF, then performing Soxhlet extraction in methanol, and then drying at 80-100°C.
[0016] According to a second aspect of the invention, the invention also provides a vinyl covalent organic framework foam prepared by the method of the first aspect.
[0017] According to a third aspect of the present invention, the present invention also provides an application of vinyl covalent organic framework foam as described in the second aspect in the fields of thermal insulation, flame retardancy, sound insulation and fire protection.
[0018] Compared with the prior art, the present invention can achieve the following beneficial effects:
[0019] The method of this invention synthesizes vinyl covalent organic framework foams (COFs) at high temperatures of 180–200°C using specific reactive monomers and organic additives. On the one hand, this method differs from traditional synthesis methods in that it does not require organic solvents. The selected organic additives are solid at room temperature, have high boiling points, and do not generate a large amount of vapor at high temperatures, making the synthesis process simple. On the other hand, this method can obtain a series of covalent organic framework foam materials with certain elasticity and toughness, convenient post-processing, and the ability to be molded on their own, which is beneficial for large-scale industrial production.
[0020] This invention utilizes specific reactive monomers and organic additives to synthesize vinyl covalent organic framework foams (COFs) via an organic additive method. This not only simplifies the existing synthesis process for vinyl covalent organic framework foams but also enhances their plasticity. Based on the advantages of organic additives, this invention enables the production of vinyl covalent organic framework foams at the kilogram level, far exceeding traditional synthesis methods and facilitating large-scale industrial production.
[0021] The organic additive method of the present invention can prepare vinyl covalent organic framework foam with high surface area, high mechanical strength and high porosity, with a pore size of 0.5nm-3.0nm and high stability, which has important application value in the field of thermal insulation.
[0022] The covalent organic framework foam material prepared by the method of this invention exhibits good thermal insulation performance due to its low density and porous structure, and also has certain flame retardant properties, making it suitable for use in a variety of special environments and showing promising practical application prospects. Attached Figure Description
[0023] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.
[0024] Figure 1 Infrared spectra of organic monomer A (2,4,6-trimethylpyridine), organic monomer B (terephthalaldehyde), and vinyl covalent organic framework foam NKCOF-41-foam from Example 1.
[0025] Figure 2 PXRD curves of NKCOF-41-foam, a vinyl covalent organic framework foam;
[0026] Figure 3 Nitrogen isotherm adsorption-desorption curves for vinyl covalent organic framework foam NKCOF-41-foam at 77K;
[0027] Figure 4 Scanning electron microscope image of NKCOF-41-foam, a vinyl covalent organic framework foam;
[0028] Figure 5 The thermal insulation effect of vinyl covalent organic framework foam NKCOF-41-foam is shown in the image.
[0029] Figure 6 Infrared spectra of organic monomer A (2,4,6-trimethylpyridine), organic monomer B (trimethylbenzene), and vinyl covalent organic framework foam NKCOF-13-foam from Example 3.
[0030] Figure 7 PXRD curves for vinyl covalent organic framework foam NKCOF-13-foam;
[0031] Figure 8 Nitrogen isotherm adsorption-desorption curves of vinyl covalent organic framework foam NKCOF-13-foam at 77K;
[0032] Figure 9 Scanning electron microscope image of NKCOF-13-foam, a vinyl covalent organic framework foam;
[0033] Figure 10 The thermal insulation effect of NKCOF-13-foam, a vinyl covalent organic framework foam;
[0034] Figure 11 The thermal insulation temperature profile of NKCOF-41-foam, a vinyl covalent organic framework foam;
[0035] Figure 12 Density curves of vinyl covalent organic framework foam NKCOF-41-foam at different benzoic acid addition levels;
[0036] Figure 13 Infrared spectra of organic monomer A (2,4,6-trimethylpyridine), organic monomer B (trimethylbenzene), and vinyl covalent organic framework foam NKCOF-13-foam from Example 3.
[0037] Figure 14 PXRD curves for vinyl covalent organic framework foam NKCOF-13-foam;
[0038] Figure 15 Nitrogen isotherm adsorption-desorption curves of vinyl covalent organic framework foam NKCOF-13-foam at 77K;
[0039] Figure 16 Pore size distribution diagram of vinyl covalent organic framework foam NKCOF-13-foam;
[0040] Figure 17 Scanning electron microscope image of NKCOF-13-foam, a vinyl covalent organic framework foam;
[0041] Figure 18 A schematic diagram of the thermal insulation of vinyl covalent organic framework foam NKCOF-13-foam.
[0042] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation
[0043] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.
[0044] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art to which this invention pertains. Unless otherwise specified, the experimental reagents used in the following embodiments are conventional biochemical reagents; and the experimental methods described are conventional methods.
[0045] Example 1
[0046] This embodiment provides a method for preparing vinyl covalent organic framework foam, including:
[0047] Weigh 0.2 mmol of 2,4,6-trimethylpyridine, 0.3 mmol of terephthalaldehyde, and 4.0 mmol of benzoic acid, and place them into a high-temperature, high-pressure resistant thick-walled glass tube. Evacuate the tube to a pressure of 0.15 mmHg. Remove the tube from the vacuum line and seal it with a flame generated by an oxyhydrogen generator to isolate the internal and external systems. React the sealed tube in an oven at 180°C for 5 days to obtain a red solid. Immerse the solid in DMF, then perform Soxhlet extraction in methanol for 10 hours to obtain an orange-yellow foamy material with a yield of approximately 80%, denoted as NKCOF-41-foam.
[0048] The reaction formula is as follows:
[0049]
[0050] Compare with Example 1
[0051] This comparative example provides a method for synthesizing covalent organic framework materials using conventional solid-state synthesis methods, including:
[0052] Weigh 0.2 mmol of 2,4,6-trimethylpyridine, 0.3 mmol of terephthalaldehyde, and 1.0 mmol of benzoic acid, and place them into a high-temperature, high-pressure resistant thick-walled glass tube. Evacuate the tube to a pressure of 0.15 mmHg. Remove the tube from the vacuum line and seal it with a flame generated by an oxyhydrogen generator to isolate the internal and external systems. React the sealed tube in an oven at 180°C for 5 days to obtain a red solid. After soaking in DMF, perform Soxhlet extraction in methanol for 10 hours to obtain an orange-yellow powder material with a yield of approximately 85%, designated NKCOF-41-powder.
[0053] Example 2
[0054] This embodiment provides a method for preparing vinyl covalent organic framework foam, including:
[0055] 0.2 mmol of 2,3,5,6-tetramethylpyrazine, 0.4 mmol of terephthalaldehyde, and 4.0 mmol of benzoic acid were weighed and placed into a high-temperature, high-pressure resistant thick-walled glass tube. The glass tube was sealed with a flame generated by an oxyhydrogen generator to isolate the internal and external systems. The sealed glass tube was reacted in an oven at 180°C for 5 days to obtain a reddish-brown lumpy solid. After soaking in DMF, it was subjected to Soxhlet extraction in methanol for 10 hours to obtain a red foamy material with a yield of approximately 80%, denoted as NKCOF-62-foam.
[0056] The reaction formula is as follows:
[0057]
[0058] Example 3
[0059] This embodiment provides a method for preparing vinyl covalent organic framework foam, including:
[0060] Weigh 0.2 mmol of 2,4,6-trimethylpyridine, 0.2 mmol of trimesin, and 4.0 mmol of benzoic acid, and place them into a high-temperature, high-pressure resistant thick-walled glass tube. Evacuate the tube to a pressure of 0.15 mmHg. Remove the tube from the vacuum line and seal it with a flame generated by an oxyhydrogen generator to isolate the internal and external systems. React the sealed tube in an oven at 200°C for 5 days to obtain a red, blocky solid. After soaking in DMF, perform a Soxhlet extraction in methanol for 10 hours to obtain a yellow, foamy material with a yield of approximately 70%, denoted as NKCOF-13-foam.
[0061] The reaction formula is as follows:
[0062]
[0063] Example 4
[0064] This embodiment provides a method for preparing vinyl covalent organic framework foam, including:
[0065] 0.2 mmol of 2,4,6-trimethylpyridine, 0.3 mmol of biphenyl dicarboxaldehyde, and 0.4 mmol of benzoic acid were weighed and placed into a high-temperature, high-pressure resistant thick-walled glass tube. The glass tube was sealed with a flame generated by an oxyhydrogen generator to isolate the internal and external systems. The sealed glass tube was reacted in an oven at 180°C for 5 days to obtain a red lumpy solid. After soaking in DMF, it was subjected to Soxhlet extraction in methanol for 10 hours to obtain a yellow lumpy material with a yield of approximately 85%, denoted as NKCOF-43-foam.
[0066] The reaction formula is as follows:
[0067]
[0068] Example 5
[0069] This embodiment provides a method for preparing vinyl covalent organic framework foam, including:
[0070] Weigh 0.2 mmol of 2,4,6-trimethylpyridine, 0.3 mmol of 2,5-dialdehyde pyridine, and 4.0 mmol of benzoic acid, and place them into a high-temperature, high-pressure resistant thick-walled glass tube. Evacuate the tube to a pressure of 0.15 mmHg. Remove the tube from the vacuum line and seal it with a flame generated by an oxyhydrogen generator to isolate the internal and external systems. React the sealed tube in an oven at 180°C for 5 days to obtain a red solid. Immerse the solid in DMF, then perform Soxhlet extraction in methanol for 10 hours to obtain an orange-yellow foamy material with a yield of approximately 80%, denoted as NKCOF-41-foam.
[0071] The reaction formula is as follows:
[0072]
[0073] Example 6
[0074] This embodiment provides a method for preparing vinyl covalent organic framework foam, including:
[0075] 0.3 mmol of 2,5-dimethylpyrazine, 0.2 mmol of trimesin, and 6.0 mmol of benzoic acid were weighed and placed into a high-temperature, high-pressure resistant thick-walled glass tube. The glass tube was sealed with a flame generated by an oxyhydrogen generator to isolate the internal and external systems. The sealed glass tube was reacted in an oven at 180°C for 5 days to obtain a brown lumpy solid. After soaking in DMF, it was subjected to Soxhlet extraction in methanol for 10 hours to obtain a brown lumpy material with a yield of approximately 85%, denoted as NKCOF-10-foam.
[0076] The reaction formula is as follows:
[0077]
[0078] Example 7
[0079] This embodiment provides a method for preparing vinyl covalent organic framework foam, including:
[0080] 0.6 mmol of trimethyltriazine, 0.6 mmol of trimesin, and 12.0 mmol of benzoic acid were weighed and placed into a high-temperature, high-pressure resistant thick-walled glass tube. The glass tube was sealed with a flame generated by an oxyhydrogen generator to isolate the internal and external systems. The sealed glass tube was reacted in an oven at 200°C for 5 days to obtain a yellow lumpy solid. After soaking in DMF, it was subjected to Soxhlet extraction in methanol for 10 hours to obtain a yellow lumpy material with a yield of approximately 87%, denoted as NKCOF-12-foam.
[0081] The reaction formula is as follows:
[0082]
[0083] Example 8
[0084] This embodiment provides a method for preparing vinyl covalent organic framework foam, including:
[0085] 0.2 mmol of trimethyltriazine, 0.3 mmol of terephthalaldehyde, and 4.0 mmol of benzoic acid were weighed and placed into a high-temperature, high-pressure resistant thick-walled glass tube. The glass tube was sealed with a flame generated by an oxyhydrogen generator to isolate the internal and external systems. The sealed glass tube was reacted in an oven at 180°C for 5 days to obtain a yellow blocky solid. After soaking in DMF, it was subjected to Soxhlet extraction in methanol for 10 hours to obtain an orange blocky material with a yield of approximately 84%, denoted as TMT-TPA-COF-foam.
[0086] The reaction formula is as follows:
[0087]
[0088] Example 9
[0089] This embodiment provides a method for preparing vinyl covalent organic framework foam, including:
[0090] 0.2 mmol of trimethyltriazine, 0.3 mmol of biphenyl dicarboxaldehyde, and 4.0 mmol of benzoic acid were weighed and placed into a high-temperature, high-pressure resistant thick-walled glass tube. The glass tube was sealed with a flame generated by an oxyhydrogen generator to isolate the internal and external systems. The sealed glass tube was reacted in an oven at 180°C for 5 days to obtain a yellow blocky solid. After soaking in DMF, it was subjected to Soxhlet extraction in methanol for 10 hours to obtain a yellow blocky material with a yield of approximately 89%, denoted as TMT-BPA-COF-foam.
[0091] The reaction formula is as follows:
[0092]
[0093] Example 10
[0094] This embodiment provides a method for preparing vinyl covalent organic framework foam, including:
[0095] 0.2 mmol of trimethyltriazine, 0.3 mmol of 2,5-dimethoxy-1,4-benzaldehyde, and 4.0 mmol of benzoic acid were weighed and placed into a high-temperature, high-pressure resistant thick-walled glass tube. The glass tube was sealed with a flame generated by an oxyhydrogen generator to isolate the internal and external systems. The sealed glass tube was reacted in an oven at 200°C for 5 days to obtain a red blocky solid. After soaking in DMF, it was Soxhlet extracted in methanol for 10 hours to obtain a yellow blocky material with a yield of approximately 85%, denoted as TMT-DMTP-COF-foam.
[0096] The reaction formula is as follows:
[0097]
[0098] Example 11
[0099] This embodiment provides a method for preparing vinyl covalent organic framework foam, including:
[0100] 0.2 mmol of trimethyltriazine, 0.3 mmol of 1,4-dialdehyde-2,5-divinylbenzene, and 4.0 mmol of benzoic acid were weighed and placed into a high-temperature, high-pressure resistant thick-walled glass tube. The glass tube was sealed with a flame generated by an oxyhydrogen generator to isolate the internal and external systems. The sealed glass tube was reacted in an oven at 180°C for 5 days to obtain a reddish-brown lumpy solid. After soaking in DMF, it was subjected to Soxhlet extraction in methanol for 10 hours to obtain a reddish-brown lumpy material with a yield of approximately 83%, denoted as NKPOP-11.
[0101] The reaction formula is as follows:
[0102]
[0103] The vinyl covalent organic framework foam NKCOF-41-foam prepared in Example 1 and the covalent organic framework NKCOF-41-powder prepared in Control Example 1 were characterized and their performance was evaluated and compared. The vinyl covalent organic framework foam NKCOF-13-foam prepared in Example 3 was also characterized and its performance was evaluated.
[0104] Figure 1 The infrared spectral results are for organic monomer A (2,4,6-trimethylpyridine), organic monomer B (terephthalaldehyde), and vinyl covalent organic framework foam NKCOF-41-foam from Example 1. Figure 1 It can be seen that NKCOF-41-foam is at 1631cm -1 The peak at the location corresponds to the stretching vibration of the carbon-carbon double bond, proving that it is a vinyl-linked COFs material.
[0105] Figure 2 PXRD patterns for vinyl covalent organic framework foam NKCOF-41-foam. From... Figure 2 It can be concluded that the foam material has considerable crystallinity.
[0106] Figure 3 The PXRD curves of the comparative covalent organic framework NKCOF-41-powder show poor crystallinity. From... Figure 2 and Figure 3 It can be seen that the NKCOF-41-foam obtained by the method used in Example 1 has higher crystallinity, which has certain advantages for subsequent applications.
[0107] Figure 4 The nitrogen isotherm adsorption-desorption curves for vinyl covalent organic framework foam NKCOF-41-foam at 77 K. Figure 4 Its BET surface area can be calculated to be 1880m². 2 / g, with a high surface area.
[0108] Figure 5 The nitrogen isotherm adsorption-desorption curves for a comparative covalent organic framework NKCOF-41-powder at 77 K are shown. Figure 5 Its BET surface area can be calculated to be 1807 m². 2 / g. From Figure 4 and Figure 5The comparison shows that the NKCOF-41-foam obtained by the synthesis method in this embodiment exhibits high adsorption in the high-pressure region under nitrogen isothermal adsorption-desorption curves at 77K, demonstrating certain mesoporous adsorption characteristics. This indicates that the synthesis method can construct larger packed pores.
[0109] Figure 6 Pore size distribution diagram of vinyl covalent organic framework foam NKCOF-41-foam.
[0110] Figure 7 This is a pore size distribution diagram of the comparative covalent organic framework NKCOF-41-powder. From... Figure 6 and Figure 7 In contrast, the NKCOF-41-foam obtained by the synthesis method in this embodiment has a new mesoporous region at 2.8 nm, which will be beneficial to the thermal insulation performance of the foam material obtained in this embodiment.
[0111] Figure 8 Scanning electron micrograph of vinyl covalent organic framework foam NKCOF-41-foam, from Figure 8 It can be seen that NKCOF-41-foam has a loose porous structure at the microscale.
[0112] Figure 9 The stress-strain curve of vinyl covalent organic framework foam NKCOF-41-foam is shown below. Figure 9 It can be seen that NKCOF-41-foam has a softer texture.
[0113] Figure 10 The stress-strain curves of the covalent organic framework NKCOF-41-powder are shown below. Figure 10 It can be seen from this that NKCOF-41-powder has a relatively hard texture.
[0114] Figure 11 The thermal insulation temperature profile of vinyl covalent organic framework foam NKCOF-41-foam is shown below. Figure 11 It is evident that NKCOF-41-foam exhibits excellent thermal insulation performance, with a thermal conductivity of 0.030 W / (m K). The covalent organic framework foam material obtained in this embodiment possesses a wider pore size distribution, and its loose structure facilitates the formation of larger cavities within the material. The air filling these cavities, acting as poor conductors of heat, can insulate against heat conduction, thus achieving a thermal insulation effect. Furthermore, its soft texture gives the foam material greater plasticity, allowing for wider application in various industrial scenarios.
[0115] Figure 12 Density curves of vinyl covalent organic framework foam NKCOF-41-foam at different benzoic acid addition levels are shown. Figure 12 It can be seen that the increase in the amount of benzoic acid added causes the density of NKCOF-41-foam to gradually decrease, and the texture to become more fluffy.
[0116] Figure 13 Infrared spectra of organic monomer A (2,4,6-trimethylpyridine), organic monomer B (trimethylbenzenealdehyde), and vinyl covalent organic framework foam NKCOF-13-foam from Example 3. Figure 13 It can be seen that the vinyl covalent organic framework foam NKCOF-13-foam at 1628cm³... -1 The peak at the location corresponds to the stretching vibration of the carbon-carbon double bond, proving that it is a vinyl-linked COF foam material.
[0117] Figure 14 The PXRD curve of the vinyl covalent organic framework foam NKCOF-13-foam shows that the foam material has considerable crystallinity.
[0118] Figure 15 The figure shows the nitrogen isotherm adsorption-desorption curves of vinyl covalent organic framework foam NKCOF-13-foam at 77 K. The BET surface area is 600 m² / g. 2 / g, the hysteresis loop of the curve proves that mesopores and macropores exist in the material.
[0119] Figure 16 The figure shows the pore size distribution of vinyl covalent organic framework foam NKCOF-13-foam. As can be seen from the figure, NKCOF-13-foam has a wider pore size distribution.
[0120] Figure 17 The image shows a scanning electron microscope (SEM) image of vinyl covalent organic framework foam NKCOF-13-foam. As can be seen from the image, the stacking of NKCOF-13-foam at the microscale is irregular.
[0121] Figure 18 This is a schematic diagram of the thermal insulation of vinyl covalent organic framework foam NKCOF-13-foam. As can be seen from the figure, NKCOF-13-foam has a good thermal insulation effect.
[0122] The vinyl covalent organic framework foam structures prepared in Examples 1-11 all contain a large number of cavities. The air inside the cavities, as a poor conductor of heat, can hinder heat conduction, thereby achieving the corresponding heat insulation effect and thus meeting the requirements for application in the field of heat insulation.
[0123] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and various changes or modifications can be made to these embodiments without departing from the principles and essence of the present invention. The scope of protection of the present invention is defined only by the appended claims.
Claims
1. A method for preparing a vinyl covalent organic framework foam material, characterized in that, Organic molecules A and B, along with organic additives, in a molar ratio of 1:(1~2):(20~60) were polymerized in a closed reactor at 180~200℃. The reaction products were then purified to obtain a vinyl covalent organic framework foam material, wherein: The organic molecule A is a pyridine or pyrazine containing at least two methyl functional groups; the organic molecule B is an aromatic compound containing two aldehyde functional groups; and the flux is a compound containing a carboxylic acid functional group.
2. The method for preparing the vinyl covalent organic framework foam material according to claim 1, characterized in that, The organic molecule A is a pyrazine containing 2 to 4 methyl functional groups or a pyridine containing 2 to 3 methyl functional groups; And / or, the organic molecule B is any one of benzene or a derivative thereof, biphenyl or a derivative thereof, naphthalene or a derivative thereof, pyridine or a derivative thereof, bipyridine or a derivative thereof, anthracene or a derivative thereof, pyrazine or a derivative thereof, or phenanthroline or a derivative thereof, containing two aldehyde functional groups.
3. The method for preparing the vinyl covalent organic framework foam material according to claim 1, characterized in that, The organic molecule A includes any one or a combination of two or more of 2,3,5,6-tetramethylpyrazine, 2,3,5-trimethylpyrazine, 2,3-dimethylpyrazine, 2,5-dimethylpyrazine, 2,6-dimethylpyridine, and 2,4,6-trimethylpyridine.
4. The method for preparing the vinyl covalent organic framework foam material according to claim 1, characterized in that, The organic molecule B includes terephthalaldehyde, biphenyl dicarboxaldehyde, pyromellitic methyl methacrylate, 2,5-dihydroxy-1,4-benzaldehyde, 1,4-dearthio-2,5-divinylbenzene, 2,3-dihydroxyterephthalaldehyde, 2,5-dibromobenzene-1,4-dicarboxaldehyde, 2,5-diethoxy-1,4-terephthalaldehyde, 2,2'-bipyridine-5,5'-dicarboxaldehyde, 1,4-bis(4-aldehydephenyl)benzene, 2,5-dearthiopyridine, 2,6-naphthalenedicarboxyl, 5-hydroxy-m-phenylenedialdehyde, and 1,10-phenanthroline-2,9-dimethylbenzene. The aldehyde, 4-hydroxy-isophthalaldehyde, anthracene-9,10-dicarboxaldehyde, 2,2'-bipyridine-4,4'-dicarboxaldehyde, 3,3'-bipyridine-6,6'-dicarboxaldehyde, 9,10-bis(4-aldehyde-phenyl)anthracene, 3,6-dimethyl-terephthalaldehyde, pyridine-2,6-dicarboxaldehyde, 2-methoxy-4,6-dialdehyde-phenol, 2-nitro-terephthalaldehyde, 2,5-dialdehyde-pyrazine, 2,3-hydroxy-1,4-dialdehyde-naphthalene, and 4,4'-dihydroxy-3,3'-glyoxal biphenyl are all selected from the list of biphenyls.
5. The method for preparing the vinyl covalent organic framework foam material according to claim 1, characterized in that, The organic additives include at least one of benzoic acid, 4-fluorobenzoic acid, acetic anhydride, acetic acid, and propionic acid.
6. The method for preparing the vinyl covalent organic framework foam material according to claim 1, characterized in that, The polymerization reaction time is 72–168 h.
7. The method for preparing the vinyl covalent organic framework foam material according to claim 1, characterized in that, The pressure of the organic additive is normal pressure or negative pressure.
8. The method for preparing the vinyl covalent organic framework foam material according to claim 1, characterized in that, The purification process specifically includes: soaking the reaction product in DMF, then performing Soxhlet extraction in methanol, and then drying at 80–100°C.
9. Vinyl covalent organic framework foam prepared by the preparation method according to any one of claims 1-8.
10. The application of the vinyl covalent organic framework foam as described in claim 9 in the fields of thermal insulation, flame retardancy, heat preservation and fire protection.