High-flame-retardant bio-based aerogel material and preparation method thereof

Abstract

The invention discloses a high-flame-retardant bio-based aerogel material and a preparation method thereof, and belongs to the technical field of flame-retardant bio-based aerogel. The high-flame-retardant bio-based aerogel material prepared by the preparation method disclosed by the invention is prepared from the following raw material components in parts by mass: 10 parts of a bio-based flame-retardant filler with a porous structure, 40 to 50 parts of a hydrophobic siloxane monomer, 12.4 to 12.6 parts of an ammonium phytate solution, 6.2 to 6.3 parts of guanosine, 31.1 to 31.4 parts of cellulose nanofibers and 0.01 to 0.02 part of benzaldehyde-polyethylene glycol-silane, the preparation method comprises the following steps: firstly, carrying out hydrolytic polycondensation on a bio-based flame-retardant filler with a porous structure and a hydrophobic siloxane monomer to form a siloxane polymer network with the bio-based flame-retardant filler as a branching center; then adding cellulose nanofibers, guanosine and an ammonium phytate solution, and performing freeze casting-freeze drying-heating post-treatment to obtain the composite material. Wherein the bio-based flame-retardant filler is obtained by compounding a porous cuttlefish ink carbon quantum dot composite material with phytic acid siloxane and trimethoxy (3-(4-nitrophenoxy) propyl) silane.

Description

Technical Field

[0001] The invention relates to a highly flame-retardant bio-based aerogel material and a preparation method thereof. Background Art

[0002] With the growing demand for high-performance, environmentally friendly materials, bio-based aerogels have garnered widespread attention due to their unique physical and chemical properties. Cellulose, one of nature's most abundant biomass resources, is a rigid macromolecule composed of glucose linked by β-1,4 glycosidic bonds. Its surface is rich in hydroxyl groups, making it highly reactive and promising a promising approach for the preparation of functional materials. Among various nanocelluloses, cellulose nanofibers (CNFs) hold a prominent position in aerogel research due to their widespread availability, simple preparation process, and large aspect ratio.

[0003] However, cellulose materials are mainly composed of C, H, and O elements, and their inherent flammability limits their scope of application, especially when these materials are made into aerogels with high porosity and high specific surface area, their flammability is further exacerbated. Therefore, how to improve the flame retardant properties of cellulose aerogels has become an important research direction. Phytic acid, as a biomass acid containing high phosphorus content, is not only inexpensive and widely available, but also a highly effective natural flame retardant. Phytic acid can promote the dehydration and cross-linking of polymer substrates into carbon, and has an ideal flame retardant effect for polysaccharide structures such as cellulose. In addition, the good water solubility of phytic acid enables it to combine with cellulose at the molecular level in aqueous solution, thereby providing uniform dispersion and enhancing the flame retardant modification effect.

[0004] Despite this, cellulose aerogel exhibits strong hydrophilicity due to its abundant internal hydroxyl groups, and the addition of ammonium phytate also enhances the material's water absorption. This makes cellulose-based aerogels susceptible to moisture absorption in humid environments, leading to performance degradation, structural damage, and ultimately shortening the material's service life.

[0005] Therefore, there is an urgent need to prepare a highly flame-retardant bio-based aerogel material with good hydrophobicity and flame retardancy. Summary of the Invention

[0006] The purpose of the present invention is to provide a highly flame-retardant bio-based aerogel material and a preparation method thereof, so as to solve the technical problems mentioned in the above background technology.

[0007] The technical solution for achieving the purpose of the present invention is:

[0008] In the first aspect, the present invention provides a highly flame-retardant bio-based aerogel material, which comprises, by weight, 10 parts by weight of a porous bio-based flame-retardant filler, 40 to 50 parts by weight of a hydrophobic siloxane monomer, 12.4 to 12.6 parts by weight of an ammonium phytate solution, 6.2 to 6.3 parts by weight of guanosine, 31.1 to 31.4 parts by weight of cellulose nanofibers, and 0.01 to 0.02 parts by weight of benzaldehyde-polyethylene glycol-silane.

[0009] Furthermore, the highly flame-retardant bio-based aerogel material is obtained by first hydrolyzing and condensing a porous bio-based flame-retardant filler and a hydrophobic siloxane monomer, then adding cellulose nanofibers, guanosine, and ammonium phytate solution, and then performing freeze casting-freeze drying-heating post-treatment.

[0010] Furthermore, the bio-based flame retardant filler is obtained by compounding a porous cuttlefish ink carbon quantum dot composite material with phytic acid siloxane and trimethoxy (3-(4-nitrophenoxy)propyl) silane; the porous cuttlefish ink carbon quantum dot composite material is obtained by preparing porous microspheres by combining cuttlefish ink carbon quantum dots with a pore-forming agent, stannous chloride dihydrate, and then loading silver and MXene.

[0011] Furthermore, the hydrophobic siloxane monomer includes any one or a combination of two of cardanol siloxane and dimethyldiethoxysilane.

[0012] In a second aspect, the present invention provides a method for preparing the highly flame-retardant bio-based aerogel material as described in the first aspect, the preparation steps comprising:

[0013] (1) Weigh and prepare the ingredients according to the corresponding mass fraction of each raw material component;

[0014] (2) benzaldehyde-polyethylene glycol-silane, hydrophobic siloxane monomer, deionized water, and ethanol were mixed uniformly, and then dropped into the ethanol dispersion of the porous bio-based flame retardant filler within 30 minutes, and then stirred and reacted at 80° C. for 4.5 to 5.5 hours to obtain a premix;

[0015] (3) Add cellulose nanofiber suspension to the premix prepared in step (2), heat to 60°C, then add guanosine and ammonium phytate solution, continue stirring for 2.5 to 3.5 hours, then pour into a mold, cool to room temperature, place in a -20°C refrigerator for prefreezing for 11.5 to 12.5 hours, then transfer to a vacuum freeze dryer for freeze drying for 47 to 49 hours, and finally heat treat at 115 to 125°C for 11.5 to 12.5 hours to obtain a highly flame retardant bio-based aerogel material.

[0016] Furthermore, the preparation method of the bio-based flame retardant filler is as follows:

[0017] A1. Soak cuttlefish ink in distilled water at room temperature overnight. Centrifuge at 4000-6000 rpm for 15-25 minutes to collect the precipitate. Repeat the soaking and centrifugation process 1-3 times to remove impurities. After washing, dry the mixture, grind it into a powder, and store it at -20°C until ready for use.

[0018] A2. The powder obtained in step A1 was mixed with 15 to 20 times its mass of distilled water and stirred evenly in a reactor, and then reacted at 180°C for 8 to 16 hours. After the reaction, it was naturally cooled to room temperature and centrifuged at 8000 rpm for 10 to 20 minutes. The supernatant was freeze-dried and stored in the dark at 4°C until use to obtain cuttlefish ink carbon quantum dots;

[0019] A3. 0.005 parts by mass of the cuttlefish ink carbon quantum dots obtained in step A2 were dissolved in distilled water to form a 0.45-0.55 mg / mL carbon quantum dot solution; under light-shielding conditions, 0.008-0.012 parts by mass of stannous chloride dihydrate, 1.17-1.18 parts by mass of 0.19 mol / L tartaric acid solution, and 0.112-0.113 parts by mass of sodium lauryl sulfate were added to 100 parts by mass of the carbon quantum dot solution, stirred at 1200-1600 rpm for 25-30 min, first heated to 160-180 ° C and kept in reaction for 1-3 h. After the reaction, cooled to room temperature and then filtered. The filter cake was washed alternately with deionized water and 95% ethanol several times until it was neutral, and then freeze-dried. The obtained microsphere hydrochloric acid solution was mixed with magnetic stirring for 25 to 35 minutes, wherein the mass volume ratio of the microspheres to the hydrochloric acid solution was 1 g:30 mL, and the hydrochloric acid solution was prepared by 1.5 mol / L hydrochloric acid and deionized water in a volume ratio of 1:4 to 6. The reaction was then carried out at 160 to 180 ° C for 4 to 6 hours. After the reaction was completed, it was cooled to room temperature, the obtained reaction solution was filtered, and the filter cake was washed alternately with deionized water and 95% ethanol several times until it was neutral. The filter cake was then freeze-dried, and porous microspheres were obtained after drying.

[0020] A4. Under light-proof conditions, the porous microspheres obtained in step A3 were dispersed in 2000 times their mass in distilled water. Then, 1.35-1.37 times the mass of the porous microspheres and 0.09-0.12 times the mass of the porous microspheres were added with silver nitrate. Ultrasonic oscillation was performed for 25-35 minutes, followed by reaction at 80°C for 11-13 hours. After the reaction, the mixture was cooled to room temperature and filtered. The filter cake was washed alternately with deionized water and 95% ethanol several times until neutral. The filter cake was then freeze-dried to obtain composite porous microspheres.

[0021] A5. Evenly disperse 0.3 parts by mass of composite porous microspheres, 9.1-9.4 parts by mass of ethanol, and 10.7-10.9 parts by mass of deionized water. Add 4.92-4.94 parts by mass of phytic acid-based siloxane and 18-19 parts by mass of ethanol dropwise within 30 minutes. Stir the mixture at 78-82°C for 4-6 hours, filter, and freeze-dry to obtain a bio-based flame-retardant filler.

[0022] Furthermore, the molar ratio of cardanol siloxane and dimethyldiethoxysilane in the hydrophobic siloxane monomer is 1:1-3; and the molar ratio of the hydrophobic siloxane monomer to deionized water and ethanol is 0.8-1:2:1.

[0023] Furthermore, the mass fraction of the cellulose nanofiber suspension is 0.34-0.36 wt%.

[0024] Furthermore, the ammonium phytate solution is prepared as follows: 6.1 to 6.3 parts by mass of 25% ammonia water is dropped into 10 parts by mass of phytic acid, and the mixture is continuously stirred in an ice-water bath for 50 to 70 minutes to obtain the ammonium phytate solution.

[0025] Furthermore, the mass fraction of the ethanol dispersion of the porous bio-based flame retardant filler is 28-30 wt%.

[0026] By adopting the above technical solution, the present invention has the following beneficial effects:

[0027] (1) The highly flame-retardant bio-based aerogel material prepared by the present invention improves the flame retardancy and hydrophobicity of the highly flame-retardant bio-based aerogel material by introducing a porous structure of bio-based flame-retardant filler, hydrophobic siloxane monomer, benzaldehyde-polyethylene glycol-silane, ammonium phytate, and guanosine.

[0028] (2) The rich melanin contained in cuttlefish juice is eumelanin composed of indole monomers DHI (5,6-dihydroxyindole) and DHICA (5,6-dihydroxyindole-2-carboxylic acid). Eumelanin and melanin amino acid polymers formed by the combination of eumelanin and protein, water and fat constitute the main components of cuttlefish juice; cuttlefish juice is very stable to light, heat and pH, and will not fade even after high-pressure heating and sterilization; the present invention uses natural biomass cuttlefish juice with abundant sources and stable performance as carbon material, adopts a one-step hydrothermal method to prepare cuttlefish juice carbon quantum dots, and prepares porous microspheres based on cuttlefish juice carbon quantum dots and pore-forming agent stannous chloride dihydrate After loading silver and MXene, a porous bio-based flame retardant filler was prepared by compounding phytic acid siloxane and trimethoxy (3- (4-nitrophenoxy) propyl) silane. A large number of active sites were formed in the porous bio-based flame retardant filler. At the same time, phytic acid siloxane and trimethoxy (3- (4-nitrophenoxy) propyl) silane were doped, and the hydrogen source sodium borohydride was introduced under the catalytic action of the porous cuttlefish ink carbon quantum dot composite material to reduce the nitrobenzene on the bio-based flame retardant filler to aniline. After introducing nitrogen and phosphorus into the bio-based flame retardant filler, highly efficient flame retardant nitrogen-phosphorus-silicon co-doped carbon quantum dots were formed, which effectively increased the flame retardant properties of the aerogel.

[0029] (3) The present invention first hydrolyzes and condenses the porous bio-based flame retardant filler, hydrophobic siloxane monomer, and benzaldehyde-polyethylene glycol-silane, wherein the bio-based flame retardant filler is phosphorus-doped and attached with phytic acid-based siloxane, and the hydrophobic siloxane monomer includes cardanol-based siloxane and dimethyldiethoxysilane. Through the hydrolysis and condensation of siloxane, a three-dimensional network structure of organic silicon is formed with the porous bio-based flame retardant filler as the fulcrum and the flexible linear polydimethyldiethoxysilane as the branch chain. The polydimethyldiethoxysilane is hydrophobic, and the introduction of cardanol-based siloxane introduces a hydrophobic long carbon chain into the side chain of the linear polydimethyldiethoxysilane molecular chain, which effectively enhances the hydrophobicity of the highly flame-retardant bio-based aerogel material. Performance; The introduction of cardanol-based siloxane and benzaldehyde-polyethylene glycol-silane flexible long chains can also give the three-dimensional network structure a higher degree of freedom of molecular chains. The molecular chains can disperse stress by stretching and rotating, thereby reducing the risk of crack propagation, and the flexibility of the long carbon chain can still be maintained at low temperatures, avoiding material embrittlement and increasing the compressive resistance of highly flame-retardant bio-based aerogel materials; at the same time, the aniline on the bio-based flame-retardant filler reacts with the benzaldehyde on the hydrolysis and condensation of benzaldehyde-polyethylene glycol-silane to form N-benzylidene aniline derivatives. When exposed to ultraviolet light, the trans-structured N-benzylidene aniline derivatives are converted into cis-structures, storing light energy in chemical bonds, thereby achieving the effect of anti-ultraviolet aging.

[0030] (4) In the present invention, after the porous structure of bio-based flame retardant filler and hydrophobic siloxane monomer are pre-mixed and reacted, cellulose nanofibers, guanosine, and ammonium phytate solution are added and subjected to freeze casting-freeze drying-heating post-treatment. Cellulose nanofibers, guanosine, and ammonium phytate form an in-situ bio-based aerogel network composited with cellulose nanofibers, guanosine, and ammonium phytate that passes through the porous structure of bio-based flame retardant filler on the basis of the organic silicon three-dimensional network structure. The double network structure with the porous structure of bio-based flame retardant filler as the support point and the organic silicon three-dimensional network structure interpenetrates, so that the organic silicon three-dimensional network and the bio-based aerogel network are evenly compounded together, effectively further increasing the compressive resistance, flame retardancy, and hydrophobicity of the highly flame-retardant bio-based aerogel material. DETAILED DESCRIPTION

[0031] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with specific implementation methods.

[0032] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

[0033] The following examples are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0034] The raw materials of the embodiments and comparative examples include:

[0035] MXene: Ti3AlC2 was dissolved in a hydrofluoric acid solution and stirred at 60°C for 20 h. The reaction solution was centrifuged at 3000 rpm for 10 min, and the precipitate was dried to obtain MXene.

[0036] Cardanol-based siloxane: 3-aminopropylmethyldimethoxysilane and cardanol glycidyl ether amine were mixed in a 1:1 ratio, and the mixture was reacted under a nitrogen atmosphere at 85°C for 1 hour to obtain cardanol-based siloxane.

[0037] Phytic acid siloxane: 3-glycidyloxypropylmethyldimethoxysilane, phytic acid, and ethanol were mixed in a molar ratio of 0.002:0.0012:4, and the mixture was stirred and reacted at 70°C for 2 hours to obtain phytic acid siloxane.

[0038] Benzaldehyde-polyethylene glycol-silane was produced by Xi'an Qiyue Biotechnology Co., Ltd. with a molecular weight of 1000.

[0039] (Example 1)

[0040] A method for preparing a highly flame-retardant bio-based aerogel material, the preparation steps comprising:

[0041] (1) Weigh and prepare the following raw material components according to their corresponding mass parts: 10 parts by mass of porous bio-based flame retardant filler, 40 parts by mass of hydrophobic siloxane monomer, 12.4 parts by mass of ammonium phytate solution, 6.2 parts by mass of guanosine, 31.4 parts by mass of cellulose nanofibers, and 0.01 parts by mass of benzaldehyde-polyethylene glycol-silane;

[0042] (2) Benzaldehyde-polyethylene glycol-silane, hydrophobic siloxane monomer, deionized water, and ethanol were mixed uniformly in a molar ratio of 0.8:2:1, and then added dropwise to an ethanol dispersion of 28 wt% of a porous bio-based flame retardant filler within 30 minutes, and then stirred at 80°C for 4.5 hours, followed by adding 0.03 parts by mass of sodium borohydride and continuing to stir for 5 minutes to obtain a premix;

[0043] (3) Add 0.34 wt% cellulose nanofiber suspension to the premix prepared in step (2), heat to 60°C, then add guanosine and ammonium phytate solution, continue stirring for 2.5 hours, then pour into a mold, cool to room temperature and place in a -20°C refrigerator for prefreezing for 11.5 hours, then transfer to a vacuum freeze dryer for freeze drying for 47 hours, and finally heat treat at 115°C for 11.5 hours to obtain a highly flame retardant bio-based aerogel material.

[0044] The preparation method of the bio-based flame retardant filler is as follows:

[0045] A1. Soak cuttlefish ink in distilled water at room temperature overnight, then centrifuge at 4000 rpm for 15 minutes to collect the precipitate. Repeat the soaking and centrifugation once more to remove impurities. After washing, dry the mixture, grind it into a powder, and store it at -20°C until ready for use.

[0046] A2. The powder obtained in step A1 was mixed with 15 times its mass of distilled water and stirred evenly in a reactor, and then reacted at 180°C for 8 hours. After the reaction, it was naturally cooled to room temperature and centrifuged at 8000 rpm for 10 minutes. The supernatant was freeze-dried and stored in the dark at 4°C until use to obtain squid ink carbon quantum dots;

[0047] A3. 0.005 parts by mass of the squid ink carbon quantum dots obtained in step A2 were dissolved in distilled water to prepare a 0.45 mg / mL carbon quantum dot solution; under light-proof conditions, 0.008 parts by mass of stannous chloride dihydrate, 1.17 parts by mass of 0.19 mol / L tartaric acid solution, and 0.112 parts by mass of sodium lauryl sulfate were added to 100 parts by mass of the carbon quantum dot solution, stirred at 1200 rpm for 25 minutes, first heated to 160 ° C and kept for 1 hour. After the reaction, it was cooled to room temperature, then filtered, and washed with deionized water and 95% ethanol alternately. The filter cake was washed several times until it was neutral, and then freeze-dried. The obtained microsphere hydrochloric acid solution was mixed with magnetic stirring for 25 minutes, wherein the mass volume ratio of the microspheres to the hydrochloric acid solution was 1g:30mL, and the hydrochloric acid solution was prepared by 1.5mol / L hydrochloric acid and deionized water in a volume ratio of 1:4. The mixture was then reacted at 160°C for 4 hours. After the reaction was completed, the mixture was cooled to room temperature. The obtained reaction solution was filtered, and the filter cake was washed alternately with deionized water and 95% ethanol several times until it was neutral. The filter cake was then freeze-dried to obtain porous microspheres after drying.

[0048] A4. Under light-shielding conditions, the porous microspheres obtained in step A3 were dispersed in 2000 times their mass in distilled water. Then, 1.35 times the mass of the porous microspheres and 0.09 times the mass of MXene were added. Ultrasonic oscillation was performed for 25 minutes, followed by reaction at 80°C for 11 hours. After the reaction, the mixture was cooled to room temperature and filtered. The filter cake was washed alternately with deionized water and 95% ethanol several times until neutral. The filter cake was then freeze-dried to obtain composite porous microspheres.

[0049] A5. 0.3 parts by mass of composite porous microspheres, 9.1 parts by mass of ethanol, and 10.7 parts by mass of deionized water were mixed and dispersed uniformly. Subsequently, 4.91 parts by mass of phytic acid siloxane, 0.01 parts by mass of trimethoxy(3-(4-nitrophenoxy)propyl)silane, and 18 parts by mass of ethanol were added dropwise within 30 minutes. The mixture was stirred at 78°C for 4 hours, filtered, and freeze-dried to obtain a bio-based flame-retardant filler.

[0050] The molar ratio of cardanol siloxane to dimethyldiethoxysilane in the hydrophobic siloxane monomer is 1:1;

[0051] The ammonium phytate solution is prepared as follows: 6.1 parts by mass of 25% ammonia water are dropped into 10 parts by mass of phytic acid, and the mixture is continuously stirred in an ice-water bath for 50 minutes to obtain the ammonium phytate solution.

[0052] (Example 2)

[0053] A method for preparing a highly flame-retardant bio-based aerogel material, the preparation steps comprising:

[0054] (1) Weigh and prepare the following raw material components according to their corresponding mass parts: 10 parts by mass of porous bio-based flame retardant filler, 45 parts by mass of hydrophobic siloxane monomer, 12.5 parts by mass of ammonium phytate solution, 6.25 parts by mass of guanosine, 31.25 parts by mass of cellulose nanofibers, and 0.015 parts by mass of benzaldehyde-polyethylene glycol-silane;

[0055] (2) Benzaldehyde-polyethylene glycol-silane, hydrophobic siloxane monomer, deionized water, and ethanol were mixed uniformly at a molar ratio of 0.9:2:1, and then added dropwise to an ethanol dispersion of 29 wt% of a porous bio-based flame retardant filler within 30 minutes, followed by stirring and reacting at 80°C for 5 hours, followed by adding 0.037 parts by mass of sodium borohydride, and continuing to stir for 6 minutes to obtain a premix;

[0056] (3) Add 0.35 wt% cellulose nanofiber suspension to the premix prepared in step (2), heat to 60°C, then add guanosine and ammonium phytate solution, continue stirring for 3 hours, then pour into a mold, cool to room temperature and place in a -20°C refrigerator for prefreezing for 12 hours, then transfer to a vacuum freeze dryer for freeze drying for 48 hours, and finally heat treat at 120°C for 12 hours to obtain a highly flame retardant bio-based aerogel material.

[0057] The preparation method of the bio-based flame retardant filler is as follows:

[0058] A1. Soak cuttlefish ink in distilled water at room temperature overnight, then centrifuge at 5000 rpm for 20 minutes to collect the precipitate. Repeat the soaking and centrifugation three times to remove impurities. After washing, dry the mixture, grind it into a powder, and store it at -20°C until ready for use.

[0059] A2. The powder obtained in step A1 was mixed with 18 times its mass of distilled water and stirred evenly in a reactor, and then reacted at 180°C for 12 hours. After the reaction, it was naturally cooled to room temperature and centrifuged at 8000 rpm for 15 minutes. The supernatant was freeze-dried and stored in the dark at 4°C until use to obtain squid ink carbon quantum dots;

[0060] A3. 0.005 parts by mass of the squid ink carbon quantum dots obtained in step A2 were dissolved in distilled water to prepare a 0.5 mg / mL carbon quantum dot solution; under light-proof conditions, 0.01 parts by mass of stannous chloride dihydrate, 1.175 parts by mass of 0.19 mol / L tartaric acid solution, and 0.1125 parts by mass of sodium lauryl sulfate were added to 100 parts by mass of the carbon quantum dot solution, stirred at 1400 rpm for 30 min, first heated to 170 ° C and kept in reaction for 2 h. After the reaction was completed, it was cooled to room temperature, then filtered, and alternately washed with deionized water and 95% ethanol. The filter cake was washed several times until it was neutral, and then freeze-dried. The obtained microsphere hydrochloric acid solution was mixed with magnetic stirring for 30 minutes, wherein the mass volume ratio of the microspheres to the hydrochloric acid solution was 1g:30mL, and the hydrochloric acid solution was prepared by 1.5mol / L hydrochloric acid and deionized water at a volume ratio of 1:5. The mixture was then reacted at 170°C for 5 hours. After the reaction was completed, the mixture was cooled to room temperature. The obtained reaction solution was filtered, and the filter cake was washed alternately with deionized water and 95% ethanol several times until it was neutral. The filter cake was then freeze-dried to obtain porous microspheres after drying.

[0061] A4. Under dark conditions, the porous microspheres obtained in step A3 were dispersed in 2000 times their mass in distilled water. Then, 1.34 times the mass of the porous microspheres and 0.1 times the mass of MXene were added. Ultrasonic oscillation was performed for 30 minutes, followed by reaction at 80°C for 12 hours. After the reaction, the mixture was cooled to room temperature and filtered. The filter cake was washed alternately with deionized water and 95% ethanol several times until neutral. The filter cake was then freeze-dried to obtain composite porous microspheres.

[0062] A5. Mix and disperse 0.3 parts by mass of composite porous microspheres, 9.3 parts by mass of ethanol, and 10.8 parts by mass of deionized water evenly. Then, add dropwise 4.915 parts by mass of phytic acid siloxane, 0.015 parts by mass of trimethoxy(3-(4-nitrophenoxy)propyl)silane, and 18.5 parts by mass of ethanol within 30 minutes. Stir the reaction at 80°C for 5 hours, filter, and freeze-dry to obtain a bio-based flame-retardant filler.

[0063] The molar ratio of cardanol siloxane to dimethyldiethoxysilane in the hydrophobic siloxane monomer is 1:2;

[0064] The ammonium phytate solution is prepared as follows: 6.2 parts by mass of 25% ammonia water are dropped into 10 parts by mass of phytic acid, and the mixture is continuously stirred in an ice-water bath for 60 minutes to obtain the ammonium phytate solution.

[0065] (Example 3)

[0066] A method for preparing a highly flame-retardant bio-based aerogel material, the preparation steps comprising:

[0067] (1) Weigh and prepare the following raw material components according to their corresponding mass parts: 10 parts by mass of porous bio-based flame retardant filler, 50 parts by mass of hydrophobic siloxane monomer, 12.6 parts by mass of ammonium phytate solution, 6.3 parts by mass of guanosine, and 31.1 parts by mass of cellulose nanofibers;

[0068] (2) Benzaldehyde-polyethylene glycol-silane, hydrophobic siloxane monomer, deionized water, and ethanol were mixed uniformly in a molar ratio of 1:2:1, and then added dropwise to a 30 wt% ethanol dispersion of a porous bio-based flame retardant filler within 30 minutes, and then stirred at 80°C for 5.5 hours, followed by adding 0.05 parts by mass of sodium borohydride and continuing to stir for 7 minutes to obtain a premix;

[0069] (3) Add 0.36 wt% cellulose nanofiber suspension to the premix prepared in step (2), heat to 60°C, then add guanosine and ammonium phytate solution, continue stirring for 3.5 hours, then pour into a mold, cool to room temperature and place in a -20°C refrigerator for prefreezing for 12.5 hours, then transfer to a vacuum freeze dryer for freeze drying for 49 hours, and finally heat treat at 125°C for 12.5 hours to obtain a highly flame retardant bio-based aerogel material.

[0070] The preparation method of the bio-based flame retardant filler is as follows:

[0071] A1. Soak cuttlefish ink in distilled water at room temperature overnight, then centrifuge at 6000 rpm for 25 minutes to collect the precipitate. Repeat the soaking and centrifugation three times to remove impurities. After washing, dry the mixture, grind it into a powder, and store it at -20°C until ready for use.

[0072] A2. The powder obtained in step A1 was mixed with 20 times its mass of distilled water and stirred evenly in a reactor, and then reacted at 180°C for 16 hours. After the reaction, it was naturally cooled to room temperature and centrifuged at 8000 rpm for 20 minutes. The supernatant was freeze-dried and stored in the dark at 4°C until use to obtain squid ink carbon quantum dots;

[0073] A3. Dissolve 0.005 parts by mass of the squid ink carbon quantum dots obtained in step A2 in distilled water to prepare a 0.55 mg / mL carbon quantum dot solution; under light-proof conditions, add 0.012 parts by mass of stannous chloride dihydrate, 1.18 parts by mass of 0.19 mol / L tartaric acid solution, and 0.113 parts by mass of sodium lauryl sulfate to 100 parts by mass of the carbon quantum dot solution, stir at 1600 rpm for 30 min, first heat to 180 ° C and keep the reaction for 3 h. After the reaction is completed, cool to room temperature, filter, and alternate with deionized water and 95% ethanol. The filter cake was washed several times until it was neutral, and then freeze-dried. The obtained microsphere hydrochloric acid solution was mixed with magnetic stirring for 35 minutes, wherein the mass volume ratio of the microspheres to the hydrochloric acid solution was 1g:30mL, and the hydrochloric acid solution was prepared by 1.5mol / L hydrochloric acid and deionized water in a volume ratio of 1:6. The mixture was then reacted at 180°C for 6 hours. After the reaction was completed, the mixture was cooled to room temperature. The obtained reaction solution was filtered, and the filter cake was washed alternately with deionized water and 95% ethanol several times until it was neutral. The filter cake was then freeze-dried to obtain porous microspheres after drying.

[0074] A4. Under light-shielding conditions, the porous microspheres obtained in step A3 were dispersed in 2000 times their mass in distilled water. Silver nitrate (1.37 times the mass of the porous microspheres) and MXene (0.12 times the mass of the porous microspheres) were then added. Ultrasonic oscillation was performed for 35 minutes, followed by a reaction at 80°C for 13 hours. After the reaction, the mixture was cooled to room temperature and filtered. The filter cake was washed alternately with deionized water and 95% ethanol several times until neutral. The filter cake was then freeze-dried to obtain composite porous microspheres.

[0075] A5. 0.3 parts by mass of composite porous microspheres, 9.4 parts by mass of ethanol, and 10.9 parts by mass of deionized water were mixed and dispersed uniformly. Subsequently, 4.92 parts by mass of phytic acid siloxane, 0.02 parts by mass of trimethoxy(3-(4-nitrophenoxy)propyl)silane, and 19 parts by mass of ethanol were added dropwise within 30 minutes. The mixture was stirred at 82°C for 6 hours, filtered, and freeze-dried to obtain a bio-based flame-retardant filler.

[0076] The molar ratio of cardanol siloxane to dimethyldiethoxysilane in the hydrophobic siloxane monomer is 1:3;

[0077] The ammonium phytate solution is prepared as follows: 6.3 parts by mass of 25% ammonia water is dropped into 10 parts by mass of phytic acid, and the mixture is continuously stirred in an ice-water bath for 70 minutes to obtain the ammonium phytate solution.

[0078] (Comparative Example 1)

[0079] The difference between Comparative Example 1 and Example 2 is that the raw material components of the highly flame-retardant bio-based aerogel material in Comparative Example 1 include 45 parts by mass of hydrophobic siloxane monomer, 12.5 parts by mass of ammonium phytate solution, 6.25 parts by mass of guanosine, 31.25 parts by mass of cellulose nanofibers, and 0.015 parts by mass of benzaldehyde-polyethylene glycol-silane; the remaining steps and components are the same as those in Example 2.

[0080] (Comparative Example 2)

[0081] The difference between Comparative Example 2 and Example 2 is that the bio-based flame retardant filler in Comparative Example 2 is obtained by compounding a porous cuttlefish ink carbon quantum dot composite material with phytic acid siloxane and trimethoxy (3- (4-nitrophenoxy) propyl) silane; the porous cuttlefish ink carbon quantum dot composite material is obtained by loading cuttlefish ink carbon quantum dots with silver and MXene; the remaining steps and components are the same as in Example 2.

[0082] (Comparative Example 3)

[0083] The difference between Comparative Example 3 and Example 2 is that the phosphorus-doped material of the bio-based flame retardant filler in Comparative Example 3 adopts trihydroxymethylphosphine oxide, and the remaining steps and components are the same as those in Example 2.

[0084] (Comparative Example 4)

[0085] The difference between Comparative Example 4 and Example 2 is that the raw material components of the highly flame-retardant bio-based aerogel material of Comparative Example 1 include 10 parts by mass of a porous bio-based flame-retardant filler, 12.5 parts by mass of ammonium phytate solution, 6.25 parts by mass of guanosine, 31.25 parts by mass of cellulose nanofibers, and 0.015 parts by mass of benzaldehyde-polyethylene glycol-silane; the remaining steps and components are the same as those in Example 2.

[0086] (Comparative Example 5)

[0087] The difference between Comparative Example 5 and Example 2 is that the hydrophobic siloxane monomer in Comparative Example 5 only uses dimethyldiethoxysilane, and the remaining steps and components are the same as those in Example 2.

[0088] (Comparative Example 6)

[0089] The difference between Comparative Example 6 and Example 2 is that the raw material components of the highly flame-retardant bio-based aerogel material of Comparative Example 6 include: 10 parts by mass of a porous bio-based flame-retardant filler, 45 parts by mass of a hydrophobic siloxane monomer, 12.5 parts by mass of ammonium phytate solution, 6.25 parts by mass of guanosine, and 31.25 parts by mass of cellulose nanofibers. The remaining steps and components are the same as those in Example 2.

[0090] (Effect Example)

[0091] Flame retardancy: The highly flame-retardant bio-based aerogel materials of the examples and comparative examples were tested for the limiting oxygen index (LOI) according to the national standard GB / T2406-1993 for foam materials. The specimen specifications were: length 100 mm, width 10 mm, and thickness 10 mm. Three parallel tests were performed and the average value was taken.

[0092] Compression performance: The high flame retardant bio-based aerogel materials of the embodiment and comparative example were compressed into a cylindrical shape with a diameter of 30 mm and a thickness of 20 mm, and the surface was flat. The compression rate was 2 mm min -1 , the samples were tested three times in parallel and the results were averaged.

[0093] Hydrophobicity test: The highly flame-retardant bio-based aerogel materials of the examples and comparative examples were tested for hydrophobicity using a hydrophobicity angle meter. Test conditions: the sample surface must be cut flat; deionized water is dripped directly onto the sample surface, and the state of the highly flame-retardant bio-based aerogel materials of the examples and comparative examples in relation to water is observed to measure the hydrophobicity angle.

[0094] UV resistance: The highly flame-retardant bio-based aerogel material samples prepared in Examples 1 to 3 and Comparative Examples 1 to 5 were irradiated for 48 hours at room temperature using a UV lamp with a wavelength of 365 nm, with the samples 10 cm away from the UV light source. The UV resistance was measured by the retention rate of the compressive stress at 70% strain before and after UV irradiation. The larger the value, the better the UV aging resistance.

[0095] Table 1 below shows the performance test results of the highly flame-retardant bio-based aerogel materials prepared in Examples and Comparative Examples:

[0096] Table 1

[0097]

[0098] As can be seen from Table 1 above, the highly flame-retardant bio-based aerogel materials prepared in Examples 1 to 3 have good flame retardancy, compression resistance, hydrophobicity, and UV resistance.

[0099] The difference between Comparative Example 1 and Example 2 is that the raw material components of the highly flame-retardant bio-based aerogel material in Comparative Example 1 do not contain a porous bio-based flame-retardant filler; the hydrophobic linear polysiloxane is randomly interspersed in the bio-based aerogel, and even local agglomeration occurs, resulting in poor flame retardancy, pressure resistance, UV resistance, and hydrophobicity of the highly flame-retardant bio-based aerogel material.

[0100] The difference between Comparative Example 2 and Example 2 is that the bio-based flame retardant filler in Comparative Example 2 is obtained by compounding a porous cuttlefish ink carbon quantum dot composite material with phytic acid siloxane and trimethoxy (3- (4-nitrophenoxy) propyl) silane; the porous cuttlefish ink carbon quantum dot composite material is obtained by loading silver and MXene on cuttlefish ink carbon quantum dots, and it is impossible to form pores for bio-based aerogel molecular chains to pass through, and thus it is impossible to form a highly flame-retardant bio-based aerogel material with an interpenetrating network structure, and local agglomeration occurs, and the obtained highly flame-retardant bio-based aerogel material has poor compressive resistance and UV resistance.

[0101] The difference between Comparative Example 3 and Example 2 is that the phosphorus-doped material of the bio-based flame retardant filler in Comparative Example 3 adopts trihydroxymethylphosphine oxide, and the hydrophobic linear polysiloxane is uniformly dispersed in the biomass aerogel by randomly interlacing and porous bio-based flame retardant fillers, and the resulting highly flame-retardant bio-based aerogel material has poor resilience.

[0102] The difference between Comparative Example 4 and Example 2 is that no hydrophobic siloxane monomer is added to the raw material components of the highly flame-retardant bio-based aerogel material of Comparative Example 1; the flame retardancy, compressive resistance and hydrophobicity of the highly flame-retardant bio-based aerogel material obtained are poor.

[0103] The difference between Comparative Example 5 and Example 2 is that the hydrophobic siloxane monomer in Comparative Example 5 only uses dimethyldiethoxysilane, and the resulting highly flame-retardant bio-based aerogel material has poor compressive resistance and hydrophobicity.

[0104] The difference between Comparative Example 6 and Example 2 is that benzaldehyde-polyethylene glycol-silane is not added in Comparative Example 6, and the obtained highly flame-retardant bio-based aerogel material has poor compressive resistance and UV resistance.

[0105] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, 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 highly flame retardant bio-based aerogel material, characterized in that: The raw material components include, by mass, 10 parts by mass of a porous bio-based flame-retardant filler, 40 to 50 parts by mass of a hydrophobic siloxane monomer, 12.4 to 12.6 parts by mass of an ammonium phytate solution, 6.2 to 6.3 parts by mass of guanosine, 31.1 to 31.4 parts by mass of cellulose nanofibers, and 0.01 to 0.02 parts by mass of benzaldehyde-polyethylene glycol-silane.

2. The highly flame-retardant bio-based aerogel material according to claim 1, characterized in that: The highly flame-retardant bio-based aerogel material is obtained by first hydrolyzing and condensing a porous bio-based flame-retardant filler, a hydrophobic siloxane monomer, and benzaldehyde-polyethylene glycol-silane, then adding cellulose nanofibers, guanosine, and ammonium phytate solution and performing freeze casting-freeze drying-heating post-treatment.

3. The highly flame-retardant bio-based aerogel material according to claim 1, characterized in that: The bio-based flame retardant filler is obtained by compounding a porous cuttlefish ink carbon quantum dot composite material with phytic acid siloxane and trimethoxy (3- (4-nitrophenoxy) propyl) silane; the porous cuttlefish ink carbon quantum dot composite material is obtained by preparing porous microspheres by combining cuttlefish ink carbon quantum dots with a pore-forming agent, stannous chloride dihydrate, and then loading silver and MXene.

4. The highly flame-retardant bio-based aerogel material according to claim 1, characterized in that: The hydrophobic siloxane monomer includes any one of cardanol siloxane and dimethyldiethoxysilane, or a combination of the two.

5. A method for preparing a highly flame-retardant bio-based aerogel material according to any one of claims 1 to 4, characterized in that: The preparation steps include: (1) Weigh and prepare the ingredients according to the corresponding mass fraction of each raw material component; (2) Benzaldehyde-polyethylene glycol-silane, hydrophobic siloxane monomer, deionized water, and ethanol were mixed uniformly, and then added dropwise to an ethanol dispersion of a porous bio-based flame retardant filler within 30 minutes, followed by stirring and reacting at 80° C. for 4.5 to 5.5 hours, followed by adding 0.03 to 0.05 parts by mass of sodium borohydride, and continuing to stir for 5 to 7 minutes to obtain a premix; (3) Add cellulose nanofiber suspension to the premix prepared in step (2), heat to 60°C, then add guanosine and ammonium phytate solution, continue stirring for 2.5 to 3.5 hours, then pour into a mold, cool to room temperature, place in a -20°C refrigerator for prefreezing for 11.5 to 12.5 hours, then transfer to a vacuum freeze dryer for freeze drying for 47 to 49 hours, and finally heat treat at 115 to 125°C for 11.5 to 12.5 hours to obtain a highly flame retardant bio-based aerogel material.

6. The method for preparing a highly flame-retardant bio-based aerogel material according to claim 5, characterized in that: The preparation method of the bio-based flame retardant filler is as follows: A1. Soak cuttlefish ink in distilled water at room temperature overnight. Centrifuge at 4000-6000 rpm for 15-25 minutes to collect the precipitate. Repeat the soaking and centrifugation process 1-3 times to remove impurities. After washing, dry the mixture, grind it into a powder, and store it at -20°C until ready for use. A2. The powder obtained in step A1 was mixed with 15 to 20 times its mass of distilled water and stirred evenly in a reactor, and then reacted at 180°C for 8 to 16 hours. After the reaction, it was naturally cooled to room temperature and centrifuged at 8000 rpm for 10 to 20 minutes. The supernatant was freeze-dried and stored in the dark at 4°C until use to obtain cuttlefish ink carbon quantum dots; A3. 0.005 parts by mass of the cuttlefish ink carbon quantum dots obtained in step A2 were dissolved in distilled water to form a 0.45-0.55 mg / mL carbon quantum dot solution; under light-shielding conditions, 0.008-0.012 parts by mass of stannous chloride dihydrate, 1.17-1.18 parts by mass of 0.19 mol / L tartaric acid solution, and 0.112-0.113 parts by mass of sodium lauryl sulfate were added to 100 parts by mass of the carbon quantum dot solution, stirred at 1200-1600 rpm for 25-30 min, first heated to 160-180 ° C and kept in reaction for 1-3 h. After the reaction, cooled to room temperature and then filtered. The filter cake was washed alternately with deionized water and 95% ethanol several times until it was neutral, and then freeze-dried. The obtained microsphere hydrochloric acid solution was mixed with magnetic stirring for 25 to 35 minutes, wherein the mass volume ratio of the microspheres to the hydrochloric acid solution was 1 g:30 mL, and the hydrochloric acid solution was prepared by 1.5 mol / L hydrochloric acid and deionized water in a volume ratio of 1:4 to 6. The reaction was then carried out at 160 to 180 ° C for 4 to 6 hours. After the reaction was completed, it was cooled to room temperature, the obtained reaction solution was filtered, and the filter cake was washed alternately with deionized water and 95% ethanol several times until it was neutral. The filter cake was then freeze-dried, and porous microspheres were obtained after drying. A4. Under light-proof conditions, the porous microspheres obtained in step A3 were dispersed in 2000 times their mass in distilled water. Then, 1.35-1.37 times the mass of the porous microspheres and 0.09-0.12 times the mass of the porous microspheres were added with silver nitrate. Ultrasonic oscillation was performed for 25-35 minutes, followed by reaction at 80°C for 11-13 hours. After the reaction, the mixture was cooled to room temperature and filtered. The filter cake was washed alternately with deionized water and 95% ethanol several times until neutral. The filter cake was then freeze-dried to obtain composite porous microspheres. A5. Mix and disperse 0.3 parts by mass of composite porous microspheres, 9.1-9.4 parts by mass of ethanol, and 10.7-10.9 parts by mass of deionized water evenly. Then, add dropwise 4.91-4.92 parts by mass of phytic acid siloxane, 0.01-0.02 parts by mass of trimethoxy(3-(4-nitrophenoxy)propyl)silane, and 18-19 parts by mass of ethanol within 30 minutes. Stir the reaction at 78-82°C for 4-6 hours, filter, and freeze-dry to obtain a bio-based flame retardant filler.

7. The method for preparing a highly flame-retardant bio-based aerogel material according to claim 5, characterized in that: The molar ratio of cardanol siloxane and dimethyldiethoxysilane in the hydrophobic siloxane monomer is 1:1-3; the molar ratio of the hydrophobic siloxane monomer to deionized water and ethanol is 0.8-1:2:

1.

8. The method for preparing a highly flame-retardant bio-based aerogel material according to claim 5, characterized in that: The mass fraction of the cellulose nanofiber suspension is 0.34-0.36 wt %.

9. The method for preparing a highly flame-retardant bio-based aerogel material according to claim 5, characterized in that: The ammonium phytate solution is prepared as follows: 6.1 to 6.3 parts by mass of 25% ammonia water are dropped into 10 parts by mass of phytic acid, and the mixture is continuously stirred in an ice-water bath for 50 to 70 minutes to obtain the ammonium phytate solution.

10. The method for preparing a highly flame-retardant bio-based aerogel material according to claim 5, characterized in that: The mass fraction of the ethanol dispersion of the porous bio-based flame retardant filler is 28-30 wt %.

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