Flame-retardant antibacterial composite material based on MOF-coated POSS (Polyhedral Oligomeric Silsesquioxane) and preparation method and application thereof

Abstract

The invention relates to a flame-retardant antibacterial composite material based on MOF (at) POSS (Polyhedral Oligomeric Silsesquioxane) as well as a preparation method and application thereof, and belongs to the technical field of development and application of functional flame-retardant antibacterial composite materials. The preparation method comprises the following steps: constructing a metal organic framework (MOF) crystal through coordination of double ligands, namely 2-methylimidazole and 4-imidazole formaldehyde, and combining with aminated polyhedral oligomeric silsesquioxane (NH2-POSS) to form a stable MOF-POSS covalent cross-linked network. According to the composite material, the surface of the cotton fabric is endowed with excellent flame retardant property and broad-spectrum antibacterial activity, the limit oxygen index and the antibacterial rate are remarkably improved, and meanwhile, the composite material has good washability and adhesion fastness. The technology overcomes the defects of insufficient durability and potential environmental safety hazards of traditional flame retardants and antibacterial agents, and meets the requirements of military and high-end protective fabrics for multiple functions and lasting and stable performance. The fabric is simple and convenient in preparation process, environment-friendly and suitable for large-scale production, popularization and application.

Description

Technical Field

[0001] The present invention relates to a flame-retardant and antibacterial composite material based on MOF@POSS, a preparation method and an application thereof, belonging to the technical field of development and application of functional flame-retardant and antibacterial composite materials, and in particular to MOF / POSS flame-retardant and antibacterial fabrics. Background Art

[0002] In modern high-risk operational environments, clothing is not only essential for shelter and protection, but also a multifunctional carrier. Especially in conditions of extreme heat, fire, chemical exposure, or pathogen contamination, the flame retardancy and antimicrobial properties of clothing materials are directly related to personnel safety and operational sustainability.

[0003] Cotton, a natural fiber material, has long been widely used in military clothing and protective equipment due to its excellent breathability and skin-friendly properties. However, cotton fiber has a low limiting oxygen index, making it highly flammable and burning rapidly, making it difficult to meet the flame retardancy requirements of modern high-performance protective fabrics. Furthermore, cotton fabric easily absorbs moisture in humid environments, promoting the growth of bacteria and microorganisms, causing odor and potential health risks, severely limiting its application in multifunctional protective applications.

[0004] Existing methods for treating fabrics with flame retardant and antibacterial functions mostly use a single functional agent or a simple superposition of different functional agents. Although this method has achieved multifunctional integration to a certain extent, it has key problems such as mutual influence between functions and performance degradation, insufficient durability, poor functional persistence, and lack of an efficient structural integration mechanism. Therefore, it is urgent to develop a new technology for fabric functional finishing that can effectively overcome the above-mentioned technical bottlenecks, focusing on solving key problems such as compatibility between multifunctional materials, bonding firmness and performance durability, and achieving deep synergy and long-term stable application of flame retardant and antibacterial functions, thereby meeting the strict requirements of modern high-performance functional textiles in terms of safety, environmental protection and service life. Summary of the Invention

[0005] The technical problem solved by the present invention is: to overcome the deficiencies of the prior art and to propose a flame retardant and antibacterial composite material based on MOF@POSS, and a preparation method and application thereof.

[0006] The technical solution of the present invention is:

[0007] A flame-retardant and antibacterial composite material based on MOF@POSS. The raw materials for preparing the flame-retardant and antibacterial composite material include zinc nitrate hexahydrate (Zn(NO3)2·6H2O), 2-methylimidazole (2-mIM), 4-imidazolecarboxaldehyde (4-ICA), octavinyl POSS, cysteamine (HS-CH2-CH2-NH2), azobisisobutyronitrile (AIBN), and a PEG-4000 aqueous solution (PEG-4000, deionized water).

[0008] Taking the total mass of the raw materials of the composite material as 100%, the mass percentage of each component is:

[0009]

[0010] A method for preparing a flame-retardant and antibacterial composite material based on MOF@POSS, the method comprising the following steps:

[0011] S1. Powder premixing: Accurately weigh 1.746 g zinc nitrate hexahydrate, 0.4925 g 2-methylimidazole, 0.660 g 4-imidazolecarboxaldehyde, and 0.75 g PEG-4000 powder. Place all powders in a clean, dry agate mortar and pestle, and grind them with a grinding rod at moderate force for 15-20 min until the powders are evenly mixed and have a uniform color, without obvious particle stratification or agglomeration, as observed by the naked eye.

[0012] S2. Fabric Pretreatment: Select a clean, dry cotton fabric sample and place it in a 250mL beaker. Add sufficient anhydrous ethanol. Ultrasonicate the sample using an ultrasonic cleaner for 10 minutes to remove surface impurities, grease, or other contaminants that may affect material bonding. After ultrasonic treatment, remove the cotton fabric and dry it in an oven at 40°C until completely dry. Set aside.

[0013] S3. Powder Hot Pressing: Lay pre-dried cotton fabric flat on a clean, flat work surface. Use a brush to evenly spread the ground mixed powder onto the fabric surface, ensuring that the powder is distributed evenly across the surface, with no accumulation or gaps. Cover with a layer of aluminum foil to prevent the powder from scattering during the hot pressing process. Place the sample in a flatbed hot press and press at 200°C and 100 MPa for 10 minutes, allowing the functional components to bond or embed into the cotton fiber surface under high temperature and pressure.

[0014] S4. Surface Cleaning and Drying: Immediately after removing the heat-pressed fabric sample, immerse it in a sufficient amount of anhydrous ethanol for 30 minutes, stirring gently to remove any unreacted PEG and other soluble residues from the surface. Afterwards, gently hand-wash the sample three times, minimizing damage to the fabric structure and mechanical damage. After cleaning, dry the sample in a vacuum drying oven at 40°C for 2 hours to ensure complete evaporation of the water and ethanol.

[0015] S5, NH2-POSS synthesis: In a clean beaker, 1.0 g of octavinyl-POSS powder was added, and 40 mL of anhydrous ethanol was added as a solvent. The magnetic stirring was started until the POSS was completely dissolved to form a clear transparent solution. Then 1.1 g of cysteamine and 0.01 g of azobisisobutyronitrile (AIBN) as a free radical initiator were added in turn, and stirring was continued for 10 min to ensure that the system was fully and uniformly mixed.

[0016] S6, Nitrogen protection polymerization reaction: The mixed solution was transferred to a 100 mL round-bottom flask, a nitrogen gas pipe was connected, and the nitrogen flow rate was maintained at about 50 mL / min for 30 min to fully replace the air in the bottle and exclude residual oxygen in the system to prevent the free radical reaction process from being terminated by oxygen. After the gas was passed, the flask was sealed and placed in a constant temperature oil bath to heat to 70-75 °C, and the magnetic stirring was kept constant for 12-24 h to realize the thiol-ene click reaction of cysteamine and POSS to generate amino-functionalized POSS.

[0017] S7, Product extraction and purification: After the reaction was completed, the flask was naturally cooled to room temperature, and the reaction solution was slowly added to 100 mL of anhydrous ether pre-cooled to 0-4 °C, and stirring was continued under magnetic stirring for 30 min to induce product precipitation. Then centrifugation was performed at 6000 rpm for 10 min, and the supernatant was discarded, and the white precipitate was collected. The precipitate was washed with 20 mL of ethanol for 3 times, and after each washing, centrifugation was performed and the supernatant was discarded. Finally, the washed precipitate was placed in a vacuum drying oven (40 °C, -0.1 MPa) for drying for 12 h to obtain the NH2-POSS product.

[0018] S8, Secondary loading treatment: The fabric pretreatment step in S2 was repeated. Then the composite powder obtained in S1 and 0.5 g of NH2-POSS powder obtained in S7 were placed in a clean and dry agate mortar, and a grinding rod was used to grind at moderate force for 15-20 min until the powder was uniformly mixed and the color was consistent, and there was no obvious particle stratification or agglomeration. The mixed powder was again evenly spread on the surface of the dry cotton fabric and covered with aluminum foil. The sample was placed in a hot pressing device and subjected to pressure treatment at 200 °C and 100 MPa for 10 min to further enhance the composite firmness and binding stability between the powder and the fabric.

[0019] S9, Final washing and drying: After the hot pressing treatment, the fabric sample was taken out, immediately immersed in ethanol for 30 min, and gently washed by hand for 3 times to completely remove the PEG, free powder and other residues on the surface that did not participate in the reaction. After washing, the sample was placed in a 40 °C vacuum drying oven for 2 h to ensure that the fabric sample was completely dried and could be used for subsequent characterization or performance testing. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 Experimental procedure steps for the examples;

[0021] Figure 2 Synthetic chemistry for the examples;

[0022] Figure 3 Oxygen index test results for the examples and comparative examples 1, 2;

[0023] Figure 4 Char length results for the examples and comparative examples 1, 2;

[0024] Figure 5 Vertical burn test experimental photographs for the examples and comparative examples 1, 2. DETAILED DESCRIPTION

[0025] The application will be further described below in conjunction with the accompanying drawings and examples.

[0026] Examples

[0027] A flame-retardant antibacterial cotton fabric based on a MOF / @POSS composite material and a preparation method thereof, comprising the following steps:

[0028] Mix 1.746 g Zn(N03)2-6H20, 0.4925 g 2-mIM, 0.660 g 4-ICA and 0.75 g PEG-4000 in a marble mortar for 15 min; clean the cotton fabric with ethanol by ultrasonic for 10 min, dry at 40 °C, spread the mixed powder evenly on the surface of the substrate, cover with aluminum foil; press uniformly at 200 °C, 100 MPa for 10 min; soak the sample in ethanol for 30 min, wash gently by hand for 3 times, remove the unreacted PEG and residues, then dry at 40 °C under vacuum for 2 h; dissolve 1.0 g octavinyl-POSS in 40 mL ethanol, magnetically stir until completely dissolved, then add 1.1 g cysteamine and 0.01 g AIBN, continue to stir for 10 min until mixed evenly; transfer the mixture to a 100 mL round-bottom flask, connect a nitrogen gas tube, pass nitrogen for 30 min (flow rate 50 mL / min), completely remove oxygen. Seal the flask, place it in an oil bath, heat to 70-75 °C, continue to stir for 12-24 h; cool to room temperature, add the reaction solution dropwise to 100 mL ice ether, stir for 30 min to induce precipitation. Centrifuge (6000 rpm, 10 min), discard the supernatant, collect the white precipitate. Wash the precipitate with 20 mL ethanol for 3 times, discard the supernatant after each centrifugation. Dry the precipitate in a vacuum drying oven (40 °C, -0.1 MPa) for 12 h; mix 1.746 g Zn(N03)2-6H20, 0.4925 g 2-mIM, 0.660 g 4-ICA, 0.5 g NH2-POSS and 0.75 g PEG-4000 in a marble mortar for 15 min; clean the cotton fabric with ethanol by ultrasonic for 10 min, dry at 40 °C, spread the mixed powder evenly on the surface of the substrate, cover with aluminum foil; press uniformly at 200 °C, 100 MPa for 10 min; soak the sample in ethanol for 30 min, wash gently by hand for 3 times, remove the unreacted PEG and residues, then dry at 40 °C under vacuum for 2 h.

[0029] Comparative Example 1

[0030] Pure cotton fabric without adding any composite material and without hot pressing.

[0031] Comparative Example 2 (only change the grammage and hot pressing temperature and time)

[0032] 0.873g Zn(NO3)2·6H2O, 0.2462g 2-mIM, 0.33g 4-ICA and 0.375g PEG-4000 were ground in an agate mortar for 15min and mixed evenly; the cotton fabric was ultrasonically cleaned with ethanol for 5min and dried at 30℃, and the mixed powder was evenly spread on the substrate surface and covered with aluminum foil; it was uniformly pressurized at 150℃ and 50MPa for 5min; the sample was soaked in ethanol for 15min, gently hand washed 3 times to remove unreacted PEG and residues, and then vacuum dried at 30℃ for 2h; 0.5g octavinyl POSS was dissolved in 20mL ethanol and magnetically stirred until completely dissolved, followed by the addition of 0.55g cysteamine and 0.01g AIBN, and stirring was continued for 10min until mixed evenly; the mixture was transferred to a 100mL round-bottom flask, connected to a nitrogen gas tube, and nitrogen was passed through for 30min (flow rate 50mL / min) to completely exclude oxygen. Seal the flask and place it in an oil bath. Heat to 50-55°C and continue stirring for 12-24 hours. After cooling to room temperature, add the reaction solution dropwise to 100 mL of icy ether and stir for 30 minutes to induce precipitation. Centrifuge (6000 rpm, 10 minutes), discard the supernatant, and collect the white precipitate. Wash the precipitate three times with 20 mL of ethanol, discarding the supernatant after each centrifugation. The precipitate was placed in a vacuum drying oven (40°C, -0.1 MPa) and dried for 12 h; 0.873 g Zn(NO3)2·6H2O, 0.2462 g 2-mIM, 0.33 g 4-ICA, 0.25 g NH2-POSS and 0.375 g PEG-4000 were ground in an agate mortar for 15 min and mixed evenly; the cotton fabric was ultrasonically cleaned with ethanol for 5 min and dried at 30°C, the mixed powder was evenly spread on the substrate surface and covered with aluminum foil; uniform pressure was applied at 150°C and 50 MPa for 5 min; the sample was soaked in ethanol for 15 min, gently hand washed 3 times to remove unreacted PEG and residues, and then vacuum dried at 30°C for 2 h.

[0033] Comparative Example 3 (only changing the gram weight and hot pressing temperature and time)

[0034] 1.3968g Zn(NO3)2·6H2O, 0.394g 2-mIM, 0.528g 4-ICA and 0.6g PEG-4000 were ground in an agate mortar for 15min to mix evenly; the cotton fabric was ultrasonically cleaned with ethanol for 5min and dried at 35℃, and the mixed powder was evenly spread on the substrate surface and covered with aluminum foil; it was uniformly pressurized at 180℃ and 80MPa for 8min; the sample was soaked in ethanol for 20min, gently hand washed 3 times to remove unreacted PEG and residues, and then vacuum dried at 35℃ for 2h; 0.8g octavinyl POSS was dissolved in 35mL ethanol and magnetically stirred until completely dissolved, followed by the addition of 0.88g cysteamine and 0.01g AIBN, and stirring was continued for 10min until mixed evenly; the mixture was transferred to a 100mL round-bottom flask, connected to a nitrogen gas tube, and nitrogen was passed for 30min (flow rate 50mL / min) to completely exclude oxygen. Seal the flask and place it in an oil bath. Heat to 60-65°C and continue stirring for 12-24 hours. After cooling to room temperature, add the reaction solution dropwise to 100 mL of icy ether and stir for 30 minutes to induce precipitation. Centrifuge (6000 rpm, 10 minutes), discard the supernatant, and collect the white precipitate. Wash the precipitate three times with 20 mL of ethanol, discarding the supernatant after each centrifugation. The precipitate was placed in a vacuum drying oven (40°C, -0.1MPa) and dried for 12h; 1.3968g Zn(NO3)2·6H2O, 0.394g 2-mIM, 0.528g 4-ICA, 0.4g NH2-POSS and 0.6g PEG-4000 were ground in an agate mortar for 15min and mixed evenly; the cotton fabric was ultrasonically cleaned with ethanol for 5min and dried at 35°C, and the mixed powder was evenly spread on the substrate surface and covered with aluminum foil; uniform pressure was applied at 180°C and 80MPa for 10min; the sample was soaked in ethanol for 20min, gently hand washed 3 times to remove unreacted PEG and residues, and then vacuum dried at 35°C for 2h.

[0035] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A flame retardant and antibacterial composite material based on MOF and functionalized POSS, characterized by: The raw materials of the composite material include zinc nitrate hexahydrate (Zn(NO3)2·6H2O), 2-methylimidazole (2-mIM), 4-imidazolecarboxaldehyde (4-ICA), octavinyl POSS, cysteamine (HS-CH2-CH2-NH2), azobisisobutyronitrile (AIBN), and PEG-4000 aqueous solution (PEG-4000, deionized water); Taking the total mass of the raw materials of the composite material as 100%, the mass percentage of each component is:

2. A method for preparing a flame retardant and antibacterial composite material based on MOF and functionalized POSS, characterized in that The steps of the method include: In the first step, zinc nitrate hexahydrate, 2-methylimidazole, 4-imidazole formaldehyde and PEG-4000 are weighed according to a predetermined mass ratio, mixed and ground evenly to obtain a premixed powder; In the second step, the cotton fabric is subjected to ethanol ultrasonic cleaning and drying treatment; In the third step, the premixed powder is evenly spread on the surface of the pretreated cotton fabric, covered with aluminum foil, and pressed in a hot press at 200°C and 100 MPa for a certain period of time to achieve powder loading on the fabric surface; In the fourth step, the fabric after hot pressing is soaked in ethanol and manually cleaned to remove unreacted residues, followed by vacuum drying; Step 5: Octavinyl POSS is mixed with cysteamine and azobisisobutyronitrile in an anhydrous ethanol solution, and reacted in an oil bath at 70-75° C. for 12-24 hours under nitrogen protection to synthesize amino POSS; Step 6: The reaction solution was added dropwise to low-temperature ether to induce precipitation, and the product of amino POSS was obtained by centrifugation, washing and vacuum drying. In the seventh step, the premixed powder obtained in the first step is mixed and ground with the amino-treated POSS, and the powder spreading, hot pressing, washing and drying steps are repeated to obtain a flame-retardant and antibacterial fabric.

3. The preparation method according to claim 1, characterized in that In the first step, the masses of zinc nitrate hexahydrate, 2-methylimidazole, 4-imidazolecarboxaldehyde and PEG-4000 are 1.746 g, 0.4925 g, 0.660 g and 0.75 g, respectively.

4. The preparation method according to claim 2, characterized in that The ultrasonic treatment time in the second step is 10 min, and the drying temperature is 40°C.

5. The preparation method according to claim 2, characterized in that The hot pressing time in the third step is 10 minutes.

6. The preparation method according to claim 2, characterized in that In the fifth step, the amount of octavinyl POSS used is 1.0 g, the amount of cysteamine used is 1.1 g, the amount of azobisisobutyronitrile used is 0.01 g, and the amount of anhydrous ethanol used in the reaction system is 40 mL.

7. The preparation method according to claim 2, characterized in that In the sixth step, the nitrogen flow rate is 50 mL / min, the nitrogen flow time is 30 min, the reaction temperature is controlled at 70-75° C., and the reaction time is 12-24 h.

8. The preparation method according to claim 2, characterized in that In the seventh step, the amount of amino-modified POSS is controlled to be about 0.5 g, and the temperature, pressure and time of the secondary hot pressing are the same as those in the third step.

9. The preparation method according to claim 2, characterized in that The final cleaning step was to soak in ethanol for 30 min and gently wash by hand three times, with a drying temperature of 40 °C and a vacuum drying time of 2 h.

10. A flame-retardant and antibacterial composite material based on MOF@POSS, and its preparation method and application, characterized by: The obtained composite material is subjected to necessary post-finishing treatment and then hot-pressed onto the surface of a cotton fabric to prepare military, protective clothing or industrial protective fabrics. This fabric, due to its excellent flame retardant properties and broad-spectrum antibacterial activity, can effectively protect the wearer from flame burns and bacterial infections in extreme environments. It is suitable for military, firefighting, emergency rescue, medical protection and other fields, meeting high safety and hygiene protection needs.

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