A flame-retardant sponge material, its preparation method and application

Abstract

The present invention relates to the field of sponge materials, and provides a flame-retardant sponge material, a preparation method thereof and an application thereof. The flame-retardant sponge material is made of the following components: phosphorus-based flame retardant modified oxidized feather-shaped carbon nanotubes, phosphorus-containing diol modified silica aerogel, polyurethane, aluminum hydroxide, ammonium polyphosphate, toluene diisocyanate, deionized water, cyclopentane, triethanolamine, dibutyltin dilaurate, epoxidized soybean oil, talcum powder, antioxidant, light stabilizer, pigment, antimony trioxide, expanded graphite, silicone surfactant and isothiazolinone antibacterial agent. The phosphorus-based flame retardant modified oxidized feather-shaped carbon nanotubes are prepared by wet oxidation and modification with dimethyl methylphosphonate, and the phosphorus-containing diol is prepared by condensation of diethyl phosphite, diethanolamine and paraformaldehyde. The sponge of the present invention has excellent mechanical and flame-retardant properties and is widely used in the fields of construction, home furnishing and transportation.

Description

Technical Field

[0001] The present invention relates to the field of sponge materials, and particularly to a flame-retardant sponge material, its preparation method and application. Background Art

[0002] Flame-retardant sponge materials have wide applications in modern industrial and consumer fields. Especially in scenarios such as furniture manufacturing, building decoration, transportation (such as automotive interiors, aircraft seats), and electronic devices where both comfort and safety need to be considered, the flame-retardant performance has become a key indicator for material selection. Due to the flammable characteristics of the polymer structure of traditional sponge materials, they may burn rapidly and release a large amount of toxic smoke in case of a fire, seriously threatening personal and property safety. Therefore, the development of sponge materials with excellent flame-retardant performance has become the focus of industry attention. In practical applications, flame-retardant sponge materials not only need to have good flame-retardant performance, such as reducing the combustion rate, reducing smoke release, and delaying the spread of fire, but also need to exhibit excellent elasticity, compression resistance, and durability in terms of mechanical properties to meet the requirements of long-term use. In addition, such materials need to maintain stability in complex environments, be able to adapt to various temperature and humidity conditions as well as mechanical stress, and also possess environmental friendliness and low toxicity to meet the requirements of modern green development. Meeting these performance requirements is of great significance for enhancing the application value of flame-retardant sponge materials, improving the safety of related products, and promoting the technological progress of the industry. It can not only significantly extend the service life of the materials, but also broaden their application scope in the high-end market, thus promoting innovation and development in the field of flame-retardant materials.

[0003] At present, although certain progress has been made in the research and development of flame-retardant sponge materials, there are still problems in that it is difficult to balance mechanical properties and flame-retardant performance. For example, Chinese Patent No. CN105860392A discloses a preparation method of a polyvinyl alcohol-based sponge material. Although the flame-retardant grade of the material is significantly improved, due to the poor compatibility between the inorganic flame retardant and the sponge matrix, the mechanical properties of the material are significantly reduced, manifested as insufficient compression resistance and resilience. In addition, Chinese Patent No. CN108034035A discloses a synergistic flame-retardant sponge. Although the modification effectively reduces the combustion rate of the material, due to the presence of a phosphate ester and halogen mixed flame retardant, it may not only release toxic smoke but also pose a potential threat to the environment. The main reason for these deficiencies is that it is difficult to simultaneously optimize the dispersion, interfacial compatibility of flame-retardant additives in the prior art and the damage to the overall structural properties of the material, resulting in significant contradictions among the mechanical properties, environmental friendliness, and flame-retardant performance of the material. Therefore, there is an urgent need to develop a new type of flame-retardant sponge material that can balance mechanical properties and flame-retardant performance, improve the overall performance of the material by optimizing the design and distribution of flame retardants, and simultaneously meet the multiple requirements of safety, environmental friendliness, and service life, so as to provide a better solution for the field of flame-retardant materials. Summary of the invention

[0004] (1) Technical issues solved

[0005] The purpose of the present invention is to provide a flame retardant sponge material and a preparation method and application thereof, so as to solve the problem that the current sponge is insufficient in mechanical properties and flame retardant properties.

[0006] (2) Technical solution

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A flame retardant sponge material, comprising the following components, by weight: 3.0-6.5 parts of phosphorus-based flame retardant modified oxidized feather-like carbon nanotubes, 4.0-6.5 parts of phosphorus-containing diol modified silica aerogel; 90-110 parts of polyurethane, 20-30 parts of aluminum hydroxide, 1.0-3.0 parts of toluene diisocyanate, 1.0-1.5 parts of deionized water, 0.5-1.5 parts of cyclopentane, and triethanolamine. 0.5~1.5 parts, dibutyltin dilaurate 0.2~0.5 parts, epoxidized soybean oil 5~10 parts, talc 5~10 parts, antioxidant 0.5~1.5 parts, light stabilizer 0.5~1.5 parts, pigment 0.1~0.5 parts, antimony trioxide 3.0~5.0 parts, expanded graphite 5~8 parts, silicone oil surfactant 0.1~0.5 parts, isothiazolinone antibacterial agent 0.1~0.3 parts.

[0009] The phosphorus-based flame retardant modified oxidized feather-like carbon nanotubes are obtained by modifying oxidized feather-like carbon nanotubes with dimethyl methylphosphonate;

[0010] The oxidized feather-shaped carbon nanotubes are obtained by wet oxidation of carbon nanotubes;

[0011] The phosphorus-containing diol-modified silica aerogel is obtained by chemically modifying silica aerogel with phosphorus-containing diol in a sol-gel method;

[0012] The phosphorus-containing diol is prepared by condensation reaction of diethyl phosphite, diethanolamine and paraformaldehyde.

[0013] Furthermore, the preparation method of the phosphorus-based flame retardant modified oxidized feather-like carbon nanotubes is as follows: in parts by weight, 40 to 60 parts of oxidized feather-like carbon nanotubes, 100 to 140 parts of dimethyl methylphosphonate and 3.0 to 6.0 parts of monobutyl tin oxide are added to a three-well culture bottle, stirred at 160 to 170° C. for 24 to 36 hours, and after the stirring is completed, the temperature is raised to 180 to 185° C. and continued to stir for 30 to 45 minutes to evaporate the unreacted dimethyl methylphosphonate, and after the evaporation is completed, the phosphorus-based flame retardant modified feather-like carbon nanotubes are obtained after cooling to room temperature.

[0014] Further, the preparation method of the oxidized feather-shaped carbon nanotubes is as follows: by weight, 10-20 parts of carbon nanotubes, 4.0-8.0 parts of sodium nitrate and 200 parts of 98 wt.% sulfuric acid are mixed in an ice bath, and then stirred at a stirring speed of 200-300 rpm for 20-30 min. While stirring, 25-30 parts of potassium permanganate are slowly added to the mixed solution. After the stirring is completed, the mixed solution is stirred in a water bath at 30-40 °C for 90-120 min. After the stirring is completed, 1000-1200 parts of deionized water are slowly added, and then stirred at 60-80 °C for 25-35 min to obtain a suspension. Then, 30 wt.% hydrogen peroxide is slowly added dropwise to the suspension, and the suspension is continuously stirred at a stirring speed of 200-300 rpm during the dropping process until the suspension becomes bright yellow. Then, the precipitate is collected by centrifugation, and the precipitate is washed 3 times with a 10 wt.% hydrochloric acid solution. Finally, the washed precipitate is dried in a vacuum drying oven at room temperature for 20-24 h to obtain the oxidized feather-shaped carbon nanotubes.

[0015] The design of modifying oxidized feather-shaped carbon nanotubes with a phosphorus-based flame retardant in the present invention is mainly used to enhance the flame retardancy and structural stability of the flame retardant sponge material. By introducing a phosphorus-based flame retardant on the surface of the oxidized feather-shaped carbon nanotubes, excellent flame retardancy is imparted to the carbon nanotubes, and at the same time, the compatibility with the polyurethane matrix is enhanced, further improving the overall flame retardant effect and mechanical properties of the material. During the preparation process, first, the carbon nanotubes are treated by wet oxidation to form abundant hydroxyl and carboxyl functional groups on their surfaces. These functional groups not only increase the chemical activity of the carbon nanotubes but also provide binding sites for subsequent phosphorus-based modification. Subsequently, through the reaction of dimethyl methylphosphonate with the oxidized feather-shaped carbon nanotubes, a phosphorus-based structure is uniformly introduced on its surface. This modification not only improves the flame retardancy of the carbon nanotubes but also enhances their dispersibility and interfacial binding ability with other components. In the flame retardant sponge material, the phosphorus-based flame retardant modified oxidized feather-shaped carbon nanotubes can form good physical and chemical bonds with the polyurethane matrix, thereby effectively inhibiting the spread of flames and the thermal decomposition of the material in a high-temperature environment. In addition, this design has good synergy with other components. For example, when acting together with aluminum hydroxide and ammonium polyphosphate, a stable char layer can be formed to further improve the flame retardant efficiency of the material; at the same time, when synergized with phosphorus-containing diol modified silica aerogel, a dense heat insulation barrier can be formed on the surface of the material, thereby effectively blocking the infiltration of heat and oxygen and delaying the further combustion of the material. This design not only makes full use of the high specific surface area and excellent mechanical properties of the carbon nanotubes but also significantly improves their flame retardant characteristics through phosphorus-based modification, ultimately achieving the synergistic optimization of flame retardancy, mechanical properties, and material stability.

[0016] In the present invention, the oxidized feather-like carbon nanotubes combine the characteristics of carbon nanotubes and graphene. The shaft part is similar to carbon nanotubes, providing excellent mechanical strength and high specific surface area, while the vane part is similar to graphene, having excellent two-dimensional sheet effects and a large surface active area. In the flame-retardant sponge material of the present invention, the oxidized feather-like carbon nanotubes are treated by wet oxidation to introduce a large number of oxygen-containing functional groups (such as hydroxyl and carboxyl groups) on the surfaces of their shafts and vanes, significantly improving their dispersibility in the polyurethane matrix and enhancing the interfacial bonding ability with other flame-retardant components and the matrix. The carbon nanotube structure in the shaft part plays a mechanical strengthening role in the material, improving the strength and toughness of the sponge; the graphene structure in the vane part provides excellent flame-retardant performance, forming a physical barrier through two-dimensional sheets to effectively block the diffusion of heat and oxygen. In addition, the synergistic effect of the oxidized feather-like carbon nanotubes and the phosphorus-based flame retardant further enhances the flame-retardant effect of the material, promoting the formation of a char layer at high temperatures and inhibiting thermal decomposition and flame propagation during combustion. Through this design, the present invention achieves a high degree of synergy among flame-retardant performance, mechanical properties, and material stability, making the sponge material have broader application value in fields such as construction, home furnishing, and transportation.

[0017] Further, the preparation method of the phosphorus-containing diol-modified silica aerogel is as follows: by weight, 18-25 parts of tetraethyl orthosilicate, 45-55 parts of absolute ethanol, and 10 parts of deionized water are mixed and magnetically stirred for 20-30 min, then 35-42 parts of phosphorus-containing diol are added and stirred for another 30-45 min to obtain solution A for standby; separately, 10-20 parts of ammonium polyphosphate and 150 parts of absolute ethanol are mixed and ultrasonicated for 45-60 min to obtain solution B, then solution B is added to the mixed solution of solution A, and then the pH of the mixed solution is adjusted to 7.5-8.0 with ammonia water. Then, the mixed solution with adjusted pH is left to stand at 45-50 °C for 300-360 min to obtain a gel. Then, the gel is put into a mixed solution of 200-250 parts of tetraethyl orthosilicate and absolute ethanol with a volume ratio of 1:1 for aging treatment for 36-48 h. After the treatment is completed, the gel is taken out and left to stand in 200 parts of n-hexane for 30-42 h. Finally, the treated gel is dried at 50-55 °C, 70-75 °C, and 110-120 °C for 2 h in sequence to finally obtain the phosphorus-containing diol-modified silica aerogel.

[0018] Further, the preparation method of the phosphorus-containing diol is as follows: by weight, 20-30 parts of diethyl phosphite, 18-22 parts of diethanolamine, 4.0-10.0 parts of paraformaldehyde, and 200 parts of chloroform are successively added to a three-necked flask equipped with a condensing reflux device and a magnetic stirring device, and then stirred at 50-60 °C for 10-15 h. During the stirring process, the phosphorus-containing diol is synthesized and the solvent is removed. After the stirring is completed, it is cooled to room temperature to obtain the phosphorus-containing diol.

[0019] The design of using phosphorus-containing diol to modify silica aerogel in the present invention is mainly used to enhance the flame retardancy and heat insulation performance of flame retardant sponge materials. By preparing phosphorus-containing diol and introducing it into the framework structure of silica aerogel, the flame retardant effect and thermal stability of the material are significantly improved. In the technical solution, the phosphorus-containing diol is prepared by the condensation reaction of diethyl phosphite, diethanolamine and paraformaldehyde. It contains rich phosphorus elements and hydroxyl structures in its molecules, and can release phosphorus oxides at high temperatures to form a stable protective layer, inhibiting thermal decomposition and flame propagation during combustion. Further introducing the phosphorus-containing diol into the silica aerogel, its microstructure is regulated by the sol-gel method, so that the modified aerogel has both a high specific surface area and excellent thermal insulation performance, and at the same time has good flame retardant characteristics. Silica aerogel itself has excellent heat insulation and low density characteristics, and the introduction of phosphorus-containing diol not only enhances its carbonization ability, but also further improves the flame spread resistance of the material through the volatile flame retardant mechanism of phosphorus elements. In the composite system of sponge materials, the phosphorus-containing diol modified silica aerogel acts synergistically with other flame retardant components. For example, it jointly improves the formation efficiency of the carbonized layer with the phosphorus-based flame retardant modified oxidized feather-like carbon nanotubes, and synergistically accelerates the gas dilution effect during pyrolysis with ammonium polyphosphate, ultimately achieving a high degree of synergy between flame retardancy and heat insulation performance. This design optimizes the microstructure and chemical composition, endows the material with excellent flame retardancy while ensuring its light weight, heat insulation and environmental friendliness and other characteristics, making it have broad application prospects in the fields of construction, home and transportation, etc.

[0020] Further, the light stabilizer is Light Stabilizer Tinuvin770 or Light Stabilizer Chimassorb944.

[0021] Further, the pigment is one or a mixture of titanium dioxide, iron oxide red or carbon black.

[0022] Further, the silicone surfactant is DC-193 water-soluble silicone oil or L-580 silicone oil.

[0023] Further, the isothiazolinone antibacterial agent is methylisothiazolinone.

[0024] The design of the present invention using a synergistic compounding of flame retardant components is mainly used to enhance the flame retardancy, mechanical properties, and overall stability of sponge materials. By combining phosphorus-based flame retardant modified oxidized feather-shaped carbon nanotubes with phosphorus-containing diol modified silica aerogel, and compounding with a polyurethane matrix and various additives, the multi-performance optimization of the material is achieved. The phosphorus-based flame retardant modified oxidized feather-shaped carbon nanotubes provide mechanical enhancement and a flame retardant barrier effect, while the phosphorus-containing diol modified silica aerogel synergistically promotes the densification of the char layer at high temperatures, further improving the material's resistance to flame spread. In addition, aluminum hydroxide and expanded graphite act as inorganic flame retardant components in the material, generating a synergistic effect with the phosphorus-containing flame retardants. They can not only dilute the combustible gases around the flame by releasing non-combustible gases but also form a heat-insulating char layer at high temperatures, further enhancing the flame retardant effect. Antimony trioxide, as a synergistic flame retardant, acts together with the phosphorus-based flame retardant, significantly improving the combustion resistance of the material through the dual mechanisms of gas-phase flame retardancy and condensed-phase flame retardancy. Polyurethane, as the matrix material, acts together with epoxy soybean oil, talcum powder, and silicone oil surfactant to ensure the mechanical properties, flexibility, and stability of the forming process of the sponge material. The addition of antioxidants and light stabilizers enhances the anti-aging performance of the material during long-term use, while isothiazolinone antibacterial agents endow the material with excellent antibacterial properties, broadening its application fields. Through the synergistic effect among the components of the present invention, the comprehensive improvement of flame retardancy, mechanical properties, thermal stability, and antibacterial properties is achieved. The finally prepared flame retardant sponge material has wide application value and is suitable for various fields such as construction, home furnishing, and transportation.

[0025] The present invention also provides a preparation method of a flame retardant sponge material, comprising the following steps:

[0026] S1. Raw material mixing: Add polyurethane, aluminum hydroxide, toluene diisocyanate, deionized water, cyclopentane, triethanolamine, dibutyltin dilaurate, epoxy soybean oil, talcum powder, antioxidant, light stabilizer, pigment, antimony trioxide, expanded graphite, silicone oil surfactant, silica aerogel, and isothiazolinone antibacterial agent into a reaction kettle according to weight parts, then stir at 300 - 350 rpm for 5 - 10 min, and then continue to add phosphorus-based flame retardant modified oxidized feather-shaped carbon nanotubes and phosphorus-containing diol modified silica aerogel and continue to stir for 10 - 20 min to obtain a uniformly dispersed mixed solution.

[0027] S2. Foaming treatment: Heat the uniformly dispersed mixed solution obtained in step S1 to 40 - 60 °C for foaming treatment for 30 - 45 min, and then let it stand for 30 - 45 min after the foaming treatment to form a preliminarily cured sponge material.

[0028] S3. Curing treatment: The sponge material preliminarily cured in S2 is dried for 4 h at 50 - 70 °C, 100 - 120 °C, and 150 - 180 °C in sequence to complete curing. After cooling to room temperature after curing is completed, a flame-retardant sponge material is obtained.

[0029] The present invention also provides an application of the flame-retardant sponge material in the fields of construction, household, and transportation.

[0030] The multi-component synergistic compounding design of the present invention is mainly used to enhance the flame retardancy, mechanical properties, and thermal stability of the flame-retardant sponge material, while ensuring its light weight, environmental protection, and multi-functional characteristics. By optimizing the formula and preparation process, the synergistic effect of each component in the material is fully exerted, realizing the comprehensive balance and improvement of performance. In the preparation method, first, each raw material is added to the reaction kettle according to a proportion and stirred and mixed. Among them, polyurethane, as the matrix material, has excellent flexibility and processability, providing the basic mechanical support and forming ability for the flame-retardant material; during the preparation process, the foaming treatment step makes the material form a uniform pore structure through heating and stirring, which not only reduces the density but also enhances the heat insulation; the multi-stage curing treatment further optimizes the microstructure and mechanical properties of the material, making it have both excellent flame-retardant effect and dimensional stability. The flame-retardant sponge material prepared by the present invention has wide application value in the fields of construction, household, and transportation, and can meet various requirements with both flame retardancy, heat insulation, mechanical properties, and environmental protection requirements, providing a high-performance flame-retardant material solution for these fields.

[0031] (3) Beneficial technical effects

[0032] 1. Through the synergistic effect of phosphorus-based flame retardant modified oxidized feather-like carbon nanotubes and phosphorus-containing diol modified silica aerogel, the present invention significantly improves the flame retardancy, mechanical properties, and thermal stability of the flame-retardant sponge material. Compared with the prior art, it solves the pain points such as poor dispersibility of the flame retardant, weak interfacial bonding, and low flame retardancy efficiency. At high temperatures, each component forms a dense heat-insulating carbonized layer and an oxygen-blocking barrier to inhibit flame propagation and delay thermal decomposition. At the same time, the optimized component ratio and process ensure the synergy of mechanical enhancement and flame retardancy efficiency of the material. This invention provides a new idea for the development of environmentally friendly high-performance flame-retardant materials and has broad application prospects in the fields of construction, household, and transportation.

[0033] 2. Through the synergistic effect of oxidizing feathery carbon nanotubes and phosphorus-based flame retardants, the present invention significantly improves the flame retardancy, mechanical properties, and material stability of flame-retardant sponges. Compared with the prior art, it solves the problems of poor dispersibility of flame retardants, weak interfacial bonding, and low flame retardancy efficiency. Oxidized feathery carbon nanotubes combine the mechanical strengthening effect of carbon nanotubes and the two-dimensional barrier effect of graphene to form a dense char layer at high temperatures, effectively blocking the diffusion of heat and oxygen. At the same time, its surface functional groups are tightly combined with the matrix and other components to ensure performance synergy. The present invention has broad application value in the fields of architecture, home furnishing, and transportation, providing a new direction for the development of high-performance flame-retardant materials.

[0034] 3. Through the synergistic effect of phosphorus-based flame retardant-modified oxidized feathery carbon nanotubes and phosphorus-containing diol-modified silica aerogel, combined with inorganic flame retardant components such as aluminum hydroxide, expanded graphite, and antimony trioxide, the present invention significantly improves the combustion resistance, mechanical properties, and thermal stability of flame-retardant sponges. Compared with the prior art, it solves the problems of low flame retardancy efficiency, poor durability, and insufficient environmental friendliness. Each component synergistically forms a dense heat-insulating char layer at high temperatures through optimized ratios, which not only inhibits flame propagation but also delays thermal decomposition. At the same time, the combination of the polyurethane matrix and additives ensures the flexibility, anti-aging performance, and antibacterial properties of the material, making it suitable for the fields of architecture, home furnishing, and transportation, showing broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is the scanning electron microscope morphology diagram of the oxidized feathery carbon nanotubes prepared in Example 1 of the present invention.

[0036] Figure 2 It is the infrared Fourier spectrum diagram of the phosphorus-based flame retardant-modified oxidized feathery carbon nanotubes and oxidized feathery carbon nanotubes prepared in Example 1 of the present invention.

[0037] Figure 3 It is the XRD pattern of the ammonium polyphosphate used in Example 1 of the present invention.

[0038] Figure 4 It is the XRD pattern of the phosphorus-containing diol-modified silica aerogel prepared in Example 1 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0040] In the case where specific conditions are not specified, the operations in the examples are carried out under conventional conditions or the conditions recommended by the manufacturer. For the reagents or instruments used, if the manufacturer is not indicated, they are all common products on the market. For the parts not mentioned in the technical content of the present invention, they will be handled with reference to the prior art. Unless otherwise specified, the following examples and comparative examples will be carried out in parallel tests and the same processing steps and parameters will be adopted. Table 1 shows the reagents required for the examples and comparative examples and the corresponding purchasing companies.

[0041] Table 1 Reagents Required for Examples and Comparative Examples and the Corresponding Purchasing Companies

[0042] Reagents company Polyurethane Shanghai MacLean Biochemical Technology Co., Ltd. Aluminum hydroxide Shanghai MacLean Biochemical Technology Co., Ltd. Toluene diisocyanate Shanghai MacLean Biochemical Technology Co., Ltd. Cyclopentane Zhejiang Hangyu Pharmaceutical Technology Co., Ltd. Triethanolamine Suzhou Qihang Biotechnology Co., Ltd. Dibutyltin dilaurate Shandong West Asia Chemical Co., Ltd. Epoxidized soybean oil Shandong West Asia Chemical Co., Ltd. talcum powder Qingdao Yujie Talc Powder Co., Ltd. Antimony trioxide Shanghai MacLean Biochemical Technology Co., Ltd. Expanded Graphite Shanghai MacLean Biochemical Technology Co., Ltd. Dimethyl methylphosphonate Shandong West Asia Chemical Co., Ltd. Monobutyltin oxide Shandong West Asia Chemical Co., Ltd. Carbon Nanotubes Xi'an Qiyue Biotechnology Co., Ltd. Sodium nitrate Guangzhou Yuanda New Materials Co., Ltd. sulfuric acid Shandong West Asia Chemical Co., Ltd. potassium permanganate Tianjin Komiou Chemical Reagent Co., Ltd. Hydrogen Peroxide Guangdong Guanghua Technology Co., Ltd. hydrochloric acid Nanjing Chemical Reagent Co., Ltd. Anhydrous ethanol Qianyan Chemical Technology (Wuhan) Co., Ltd. Ammonium Polyphosphate Guangdong Wengjiang Chemical Reagent Co., Ltd. ammonia Shanghai Ruiyan Petrochemical Co., Ltd. Tetraethyl orthosilicate Shanghai MacLean Biochemical Technology Co., Ltd. n-Hexane China National Pharmaceutical Group Corporation Diethyl phosphite Zhejiang Hangyu Pharmaceutical Technology Co., Ltd. Diethanolamine Shandong Mantanghong New Materials Co., Ltd. Paraformaldehyde Xilong Scientific Co., Ltd. Chloroform Jinan Jinhao Chemical Co., Ltd. Light stabilizer Tinuvin770 Guangdong Wengjiang Chemical Reagent Co., Ltd. Light stabilizer Chimassorb944 Guangdong Wengjiang Chemical Reagent Co., Ltd. Titanium dioxide Shandong Mantanghong New Materials Co., Ltd. Iron oxide red Shandong Mantanghong New Materials Co., Ltd. Carbon Black Shandong Mantanghong New Materials Co., Ltd. DC-193 water soluble silicone oil Shandong Mantanghong New Materials Co., Ltd. L-580 Silicone Oil Shandong Mantanghong New Materials Co., Ltd. Methylisothiazolinone Shanghai MacLean Biochemical Technology Co., Ltd. Example 1

[0043] A flame-retardant sponge material, in parts by weight, comprises the following components: 3.0 parts of phosphorus-based flame retardant modified oxidized feather-shaped carbon nanotubes, 4.0 parts of phosphorus-containing diol modified silica aerogel; 90 parts of polyurethane, 20 parts of aluminum hydroxide, 1.0 part of toluene diisocyanate, 1.0 part of deionized water, 0.5 part of cyclopentane, 0.5 part of triethanolamine, 0.2 part of dibutyltin dilaurate, 5 parts of epoxy soybean oil, 5 parts of talcum powder, 0.5 part of antioxidant, 0.5 part of light stabilizer Tinuvin770, 0.1 part of titanium dioxide, 3.0 parts of antimony trioxide, 5 parts of expanded graphite, 0.1 part of DC-193 water-soluble silicone oil, 0.1 part of methylisothiazolinone;

[0044] The phosphorus-based flame retardant modified oxidized feather-shaped carbon nanotubes are obtained by modifying oxidized feather-shaped carbon nanotubes with dimethyl methylphosphonate; the oxidized feather-shaped carbon nanotubes are obtained by wet oxidation of carbon nanotubes; the phosphorus-containing diol modified silica aerogel is obtained by chemically modifying silica aerogel with phosphorus-containing diol in the sol-gel method; the phosphorus-containing diol is prepared by the condensation reaction of diethyl phosphite, diethanolamine and paraformaldehyde.

[0045] The preparation method of the phosphorus-based flame retardant modified oxidized feather-shaped carbon nanotubes in this example is as follows: In parts by weight, 40 parts of oxidized feather-shaped carbon nanotubes, 100 parts of dimethyl methylphosphonate and 3.0 parts of monobutyltin oxide are added to a three-necked culture flask, stirred at 160 °C for 24 h, and after stirring is completed, the temperature is raised to 180 °C and stirring is continued for 30 min to evaporate the unreacted dimethyl methylphosphonate. After evaporation is completed, it is cooled to room temperature to obtain phosphorus-based flame retardant modified feather-shaped carbon nanotubes.

[0046] The preparation method of the oxidized feather-like carbon nanotubes in this embodiment is as follows: By weight, 10 parts of carbon nanotubes, 4.0 parts of sodium nitrate and 200 parts of 98 wt.% sulfuric acid are mixed in an ice bath, and then stirred at a stirring speed of 200 rpm for 20 min. While stirring, 25 parts of potassium permanganate are slowly added to the mixed solution. After the stirring is completed, the mixed solution is stirred in a water bath at 30 °C for 90 min. After the stirring is completed, 1000 parts of deionized water are slowly added, and then stirred at 60 °C for 25 min to obtain a suspension. Then, 30 wt.% hydrogen peroxide is slowly added dropwise to the suspension, and the suspension is continuously stirred at a stirring speed of 200 rpm during the dropping process until the suspension becomes bright yellow. Then, the precipitate is collected by centrifugation, and the precipitate is washed 3 times with a 10 wt.% hydrochloric acid solution. Finally, the washed precipitate is dried in a vacuum drying oven at room temperature for 20 h to obtain the oxidized feather-like carbon nanotubes.

[0047] The preparation method of the phosphorus-containing diol modified silica aerogel in this embodiment is as follows: By weight, 18 parts of tetraethyl orthosilicate, 45 parts of absolute ethanol and 10 parts of deionized water are mixed and magnetically stirred for 20 min, and then 35 parts of phosphorus-containing diol are added and stirred for another 30 min to obtain solution A for standby; separately, 10 parts of ammonium polyphosphate and 150 parts of absolute ethanol are mixed and ultrasonically treated for 45 min to obtain solution B. Then, solution B is added to the mixed solution of solution A, and then the pH of the mixed solution is adjusted to 7.5 with ammonia water. Then, the mixed solution after pH adjustment is left standing at 45 °C for 300 min to obtain a gel. Then, the gel is put into a mixed solution of 200 parts of tetraethyl orthosilicate and absolute ethanol with a volume ratio of 1:1 for aging treatment for 36 h. After the treatment is completed, the gel is taken out and put into 200 parts of n-hexane and left standing for 30 h. Finally, the treated gel is dried at 50 °C, 70 °C and 110 °C for 2 h in sequence, and finally the phosphorus-containing diol modified silica aerogel is obtained.

[0048] The preparation method of the phosphorus-containing diol in this embodiment is as follows: By weight, 20 parts of diethyl phosphite, 18 parts of diethanolamine, 4.0 parts of paraformaldehyde and 200 parts of chloroform are sequentially added to a three-necked flask equipped with a condensing reflux device and a magnetic stirring device, and then stirred at 50 °C for 10 h. During the stirring process, the phosphorus-containing diol is synthesized and the solvent is removed. After the stirring is completed, it is cooled to room temperature to obtain the phosphorus-containing diol.

[0049] The preparation method of a flame-retardant sponge material in this embodiment includes the following steps:

[0050] S1. Raw material mixing: Add polyurethane, aluminum hydroxide, toluene diisocyanate, deionized water, cyclopentane, triethanolamine, dibutyltin dilaurate, epoxy soybean oil, talcum powder, antioxidant, light stabilizer Tinuvin770, titanium dioxide, antimony trioxide, expanded graphite, DC-193 water-soluble silicone oil and methylisothiazolinone into the reaction kettle according to the weight parts, then stir at 300 rpm for 5 min, and then continue to add phosphorus-based flame retardant modified oxidized feather-like carbon nanotubes and phosphorus-containing diol modified silica aerogel and stir for another 10 min to obtain a uniformly dispersed mixed solution.

[0051] S2. Foaming treatment: Heat the uniformly dispersed mixed solution obtained in step S1 to 40 °C for foaming treatment for 60 min, and then let it stand for 30 min after the foaming treatment to form a preliminarily cured sponge material.

[0052] S3. Curing treatment: Dry the preliminarily cured sponge material obtained in S2 at 50 °C, 100 °C and 150 °C for 4 h in sequence to complete the curing. After cooling to room temperature after the curing is completed, a flame-retardant sponge material is obtained.

[0053] Figure 1 The scanning electron microscope morphology diagram of the oxidized feather-like carbon nanotubes prepared in Example 1 of the present invention is shown. The darker-colored rachis part shows structural characteristics similar to those of carbon nanotubes, providing excellent mechanical strength and high specific surface area, while the vane part presents morphological characteristics similar to those of graphene. Figure 2 The infrared Fourier spectrum diagram of phosphorus-based flame retardant modified oxidized feather-like carbon nanotubes and oxidized feather-like carbon nanotubes shows that the characteristic absorption peaks at 1204 and 1027 cm⁻¹ correspond to the vibration absorption of P═O and P-O-C groups respectively, proving that the phosphorus-containing group has been successfully grafted onto the surface of the oxidized feather-like carbon nanotubes through dimethyl methylphosphonate. Figure 3 The XRD pattern of ammonium polyphosphate in Example 1 of the present invention is shown, verifying the effectiveness of its phase. Figure 4 The XRD pattern of phosphorus-containing diol modified silica aerogel is shown, which also proves the effectiveness of its phase, indicating that the materials prepared in the present invention meet the design requirements in terms of structure and composition. Example 2

[0054] A flame-retardant sponge material, in parts by weight, comprises the following components: 4.1 parts of phosphorus-based flame retardant modified oxidized feather-shaped carbon nanotubes, 4.8 parts of phosphorus-containing diol modified silica aerogel; 96 parts of polyurethane, 23 parts of aluminum hydroxide, 1.6 parts of toluene diisocyanate, 1.2 parts of deionized water, 0.8 part of cyclopentane, 0.8 part of triethanolamine, 0.3 part of dibutyltin dilaurate, 6.5 parts of epoxy soybean oil, 6.5 parts of talcum powder, 0.8 part of antioxidant, 0.8 part of light stabilizer Chimassorb944, 0.2 part of carbon black, 3.6 parts of antimony trioxide, 5.9 parts of expanded graphite, 0.2 part of L-580 silicone oil, 0.2 part of methylisothiazolinone.

[0055] The phosphorus-based flame retardant modified oxidized feather-shaped carbon nanotubes are obtained by modifying oxidized feather-shaped carbon nanotubes with dimethyl methylphosphonate; the oxidized feather-shaped carbon nanotubes are obtained by wet oxidation of carbon nanotubes; the phosphorus-containing diol modified silica aerogel is obtained by chemically modifying silica aerogel with phosphorus-containing diol in the sol-gel method; the phosphorus-containing diol is prepared by the condensation reaction of diethyl phosphite, diethanolamine and paraformaldehyde.

[0056] The preparation method of the phosphorus-based flame retardant modified oxidized feather-shaped carbon nanotubes in this example is as follows: in parts by weight, 46 parts of oxidized feather-shaped carbon nanotubes, 112 parts of dimethyl methylphosphonate and 3.9 parts of monobutyltin oxide are added into a three-necked culture flask, stirred at 163 °C for 28 h, after stirring, the temperature is raised to 182 °C and stirring is continued for 35 min to evaporate the unreacted dimethyl methylphosphonate, after evaporation is completed, it is cooled to room temperature to obtain phosphorus-based flame retardant modified feather-shaped carbon nanotubes.

[0057] The preparation method of the oxidized feather-shaped carbon nanotubes in this example is as follows: in parts by weight, 13 parts of carbon nanotubes, 5.2 parts of sodium nitrate and 200 parts of 98 wt.% sulfuric acid are mixed in an ice bath, then stirred at a stirring speed of 230 rpm for 23 min, while stirring, 26.5 parts of potassium permanganate are slowly added into the mixed solution, after stirring is completed, the mixed solution is stirred in a water bath at 33 °C for 99 min, after stirring is completed, 1060 parts of deionized water are slowly added, then stirred at 66 °C for 28 min to obtain a suspension, then 30 wt.% hydrogen peroxide is slowly added dropwise into the suspension, and during the dropping process, stirring is continued at a stirring speed of 230 rpm until the suspension turns bright yellow, then the precipitate is collected by centrifugation, and the precipitate is washed 3 times with 10 wt.% hydrochloric acid solution, finally, the washed precipitate is dried in a vacuum drying oven at room temperature for 21 h to obtain oxidized feather-shaped carbon nanotubes.

[0058] The preparation method of the phosphorus-containing diol modified silica aerogel in this embodiment is as follows: By weight, 20.1 parts of tetraethyl orthosilicate, 48 parts of absolute ethanol, and 10 parts of deionized water are mixed and magnetically stirred for 23 min, then 37.1 parts of phosphorus-containing diol are added and stirred for another 35 min to obtain solution A for standby; Separately, 13 parts of ammonium polyphosphate and 150 parts of absolute ethanol are mixed and ultrasonicated for 50 min to obtain solution B, then solution B is added to the mixed solution of solution A, and then the pH of the mixed solution is adjusted to 7.7 with ammonia water, and then the mixed solution after pH adjustment is left standing at 47 °C for 318 min to obtain a gel. Then the gel is put into 215 parts of a mixed solution of tetraethyl orthosilicate and absolute ethanol with a volume ratio of 1:1 for aging treatment for 40 h. After the treatment is completed, the gel is taken out and put into 200 parts of n-hexane and left standing for 34 h. Finally, the treated gel is dried at 52 °C, 72 °C, and 113 °C for 2 h in sequence, and finally the phosphorus-containing diol modified silica aerogel is obtained.

[0059] The preparation method of the phosphorus-containing diol in this embodiment is as follows: By weight, 23 parts of diethyl phosphite, 19.2 parts of diethanolamine, 5.8 parts of paraformaldehyde, and 200 parts of chloroform are successively added to a three-necked flask equipped with a condensing reflux device and a magnetic stirring device, and then stirred at 53 °C for 12 h. During the stirring process, the phosphorus-containing diol is synthesized and the solvent is removed. After the stirring is completed, it is cooled to room temperature to obtain the phosphorus-containing diol.

[0060] The preparation method of a flame-retardant sponge material in this embodiment includes the following steps:

[0061] S1. Raw material mixing: Polyurethane, aluminum hydroxide, toluene diisocyanate, deionized water, cyclopentane, triethanolamine, dibutyltin dilaurate, epoxy soybean oil, talcum powder, antioxidant, light stabilizer Chimassorb944, carbon black, antimony trioxide, expanded graphite, L-580 silicone oil, and methylisothiazolinone are added to the reaction kettle according to weight parts, and then stirred at 315 rpm for 7 min. Then, the phosphorus-based flame retardant modified oxidized feather-like carbon nanotubes and the phosphorus-containing diol modified silica aerogel are continuously added and stirred for another 13 min to obtain a uniformly dispersed mixed solution.

[0062] S2. Foaming treatment: The uniformly dispersed mixed solution obtained in step S1 is heated to 46 °C for foaming treatment for 55 min, and then left standing for 35 min after the foaming treatment to form a preliminarily cured sponge material.

[0063] S3. Curing treatment: The preliminarily cured sponge material in S2 is dried at 56 °C, 106 °C, and 159 °C for 4 h in sequence to complete curing. After the curing is completed and cooled to room temperature, a flame-retardant sponge material is obtained. Example 3

[0064] A flame-retardant sponge material, in parts by weight, comprises the following components: 5 parts of phosphorus-based flame retardant modified oxidized feather-shaped carbon nanotubes, 5.5 parts of phosphorus-containing diol modified silica aerogel; 102 parts of polyurethane, 26 parts of aluminum hydroxide, 2.2 parts of toluene diisocyanate, 1.3 parts of water, 1.1 parts of cyclopentane, 1.1 parts of triethanolamine, 0.4 parts of dibutyltin dilaurate, 8 parts of epoxy soybean oil, 8 parts of talcum powder, 1.1 parts of antioxidant, 1.1 parts of light stabilizer Tinuvin770, 0.3 parts of iron oxide red, 4.2 parts of antimony trioxide, 6.8 parts of expanded graphite, 0.3 parts of L-580 silicone oil, 0.2 parts of methylisothiazolinone.

[0065] The phosphorus-based flame retardant modified oxidized feather-shaped carbon nanotubes are obtained by modifying oxidized feather-shaped carbon nanotubes with dimethyl methylphosphonate; the oxidized feather-shaped carbon nanotubes are obtained by wet oxidation of carbon nanotubes; the phosphorus-containing diol modified silica aerogel is obtained by chemically modifying silica aerogel with phosphorus-containing diol in the sol-gel method; the phosphorus-containing diol is prepared by the condensation reaction of diethyl phosphite, diethanolamine and paraformaldehyde.

[0066] The preparation method of the phosphorus-based flame retardant modified oxidized feather-shaped carbon nanotubes in this example is as follows: in parts by weight, 52 parts of oxidized feather-shaped carbon nanotubes, 124 parts of dimethyl methylphosphonate and 4.8 parts of monobutyltin oxide are added to a three-necked culture flask, stirred at 166 °C for 31 h, and after stirring is completed, the temperature is raised to 183 °C and stirring is continued for 39 min to evaporate the unreacted dimethyl methylphosphonate. After evaporation is completed, it is cooled to room temperature to obtain phosphorus-based flame retardant modified feather-shaped carbon nanotubes.

[0067] The preparation method of the oxidized feather-shaped carbon nanotubes in this example is as follows: in parts by weight, 16 parts of carbon nanotubes, 6.4 parts of sodium nitrate and 200 parts of 98 wt.% sulfuric acid are mixed in an ice bath, and then stirred at a stirring speed of 260 rpm for 26 min. While stirring, 28 parts of potassium permanganate are slowly added to the mixed solution. After stirring is completed, the mixed solution is stirred in a water bath at 36 °C for 108 min. After stirring is completed, 1120 parts of deionized water are slowly added, and then stirring is continued at 72 °C for 31 min to obtain a suspension. Then, 30 wt.% hydrogen peroxide is slowly added dropwise to the suspension, and stirring is continued at a stirring speed of 260 rpm during the dropping process until the suspension becomes bright yellow. Then, the precipitate is collected by centrifugation, and the precipitate is washed 3 times with 10 wt.% hydrochloric acid solution. Finally, the washed precipitate is dried in a vacuum drying oven at room temperature for 22.4 h to obtain oxidized feather-shaped carbon nanotubes.

[0068] The preparation method of the phosphorus-containing diol modified silica aerogel in this example is as follows: By weight, 22.2 parts of tetraethyl orthosilicate, 51 parts of absolute ethanol, and 10 parts of deionized water are mixed and magnetically stirred for 26 min, then 39.2 parts of phosphorus-containing diol are added and stirred for another 39 min to obtain solution A for standby; separately, 16 parts of ammonium polyphosphate and 150 parts of absolute ethanol are mixed and ultrasonically treated for 54 min to obtain solution B, then solution B is added to the mixed solution of solution A, and then the pH of the mixed solution is adjusted to 7.8 with ammonia water. Then, the mixed solution with adjusted pH is left standing at 48 °C for 336 min to obtain a gel. Then, the gel is put into 230 parts of a mixed solution of tetraethyl orthosilicate and absolute ethanol with a volume ratio of 1:1 for aging treatment for 43.2 h. After the treatment is completed, the gel is taken out and put into 200 parts of n-hexane and left standing for 37.2 h. Finally, the treated gel is dried at 53 °C, 73 °C, and 116 °C for 2 h in sequence, and finally, the phosphorus-containing diol modified silica aerogel is obtained.

[0069] The preparation method of the phosphorus-containing diol in this example is as follows: By weight, 26 parts of diethyl phosphite, 20.4 parts of diethanolamine, 7.6 parts of paraformaldehyde, and 200 parts of chloroform are successively added into a three-necked flask equipped with a condensing reflux device and a magnetic stirring device, and then stirred at 56 °C for 13 h. During the stirring process, the phosphorus-containing diol is synthesized and the solvent is removed. After the stirring is completed, it is cooled to room temperature to obtain the phosphorus-containing diol.

[0070] The preparation method of a flame-retardant sponge material in this example includes the following steps:

[0071] S1. Raw material mixing: Polyurethane, aluminum hydroxide, toluene diisocyanate, deionized water, cyclopentane, triethanolamine, dibutyltin dilaurate, epoxy soybean oil, talcum powder, antioxidant, light stabilizer Tinuvin770, iron oxide red, antimony trioxide, expanded graphite, L-580 silicone oil, and methylisothiazolinone are added to the reaction kettle according to weight parts, and then stirred at 330 rpm for 8 min. Then, the phosphorus-based flame retardant modified oxidized feather-shaped carbon nanotubes and the phosphorus-containing diol modified silica aerogel are continuously added and stirred for 16 min to obtain a uniformly dispersed mixed solution.

[0072] S2. Foaming treatment: The uniformly dispersed mixed solution obtained in step S1 is heated to 52 °C for foaming treatment for 45 min, and after the foaming treatment is completed, it is left standing for 39 min to form a preliminarily cured sponge material.

[0073] S3. Curing treatment: The sponge material preliminarily cured in S2 is dried at 62 °C, 112 °C, and 168 °C for 4 h in sequence to complete curing. After the curing is completed and cooled to room temperature, a flame-retardant sponge material is obtained. Example 4

[0074] A flame retardant sponge material comprises the following components in parts by weight: 6.5 parts of phosphorus-based flame retardant modified oxidized feather-like carbon nanotubes, 6.5 parts of phosphorus-containing diol modified silica aerogel; 110 parts of polyurethane, 30 parts of aluminum hydroxide, 3.0 parts of toluene diisocyanate, 1.5 parts of deionized water, 1.5 parts of cyclopentane, 1.5 parts of triethanolamine, 0.5 parts of dibutyltin dilaurate, 10 parts of epoxy soybean oil, 10 parts of talc, 1.5 parts of antioxidant, 1.5 parts of light stabilizer Tinuvin770, 0.5 parts of pigment, 5.0 parts of antimony trioxide, 8 parts of expanded graphite, 0.5 parts of L-580 silicone oil and 0.3 parts of methylisothiazolinone; the pigment is a mixture of titanium dioxide, red iron oxide and carbon black in a ratio of 1:1:1.

[0075] Phosphorus-based flame retardant modified oxidized feather-like carbon nanotubes are obtained by modifying oxidized feather-like carbon nanotubes with dimethyl methylphosphonate; oxidized feather-like carbon nanotubes are obtained by wet oxidation of carbon nanotubes; phosphorus-containing diol modified silica aerogel is obtained by chemically modifying silica aerogel with phosphorus-containing diol in a sol-gel method; phosphorus-containing diol is prepared by condensation reaction of diethyl phosphite, diethanolamine and polyformaldehyde.

[0076] The preparation method of the phosphorus-based flame retardant modified oxidized feather-like carbon nanotubes in this embodiment is as follows: in parts by weight, 60 parts of oxidized feather-like carbon nanotubes, 140 parts of dimethyl methylphosphonate and 6.0 parts of monobutyl tin oxide are added to a three-hole culture bottle, stirred at 170°C for 36 hours, and after the stirring is completed, the temperature is raised to 185°C and stirring is continued for 45 minutes to evaporate the unreacted dimethyl methylphosphonate. After the evaporation is completed, the phosphorus-based flame retardant modified feather-like carbon nanotubes are obtained after cooling to room temperature.

[0077] The preparation method of the oxidized feather-like carbon nanotubes of this embodiment is as follows: in parts by weight, 20 parts of carbon nanotubes, 8.0 parts of sodium nitrate and 200 parts of 98wt.% sulfuric acid are mixed in an ice bath, and then stirred at a stirring speed of 300rpm for 30min. While stirring, 30 parts of potassium permanganate are slowly added to the mixture, and the mixture is stirred in a water bath at 40°C for 120min. After the stirring is completed, 1200 parts of deionized water are slowly added, and then stirring is continued at 80°C for 35min to obtain a suspension, and then 30wt.% hydrogen peroxide is slowly added dropwise into the suspension, and stirring is continued at a stirring speed of 300rpm during the dropping process until the suspension turns bright yellow, and then the precipitate is collected by centrifugation, and the precipitate is washed 3 times with a 10wt.% hydrochloric acid solution, and finally the washed precipitate is dried in a vacuum drying oven at room temperature for 24h to obtain the oxidized feather-like carbon nanotubes.

[0078] The preparation method of the phosphorus-containing diol modified silica aerogel in this example is as follows: By weight, 25 parts of tetraethyl orthosilicate, 55 parts of absolute ethanol and 10 parts of deionized water are mixed and magnetically stirred for 30 min, then 42 parts of phosphorus-containing diol are added and stirred continuously for 45 min to obtain solution A for standby; Another 20 parts of ammonium polyphosphate and 150 parts of absolute ethanol are mixed and ultrasonically treated for 60 min to obtain solution B, then solution B is added to the mixed solution of solution A, and then the pH of the mixed solution is adjusted to 8.0 with ammonia water, and then the mixed solution after pH adjustment is allowed to stand at 50 °C for 360 min to obtain a gel. Then the gel is placed in 250 parts of a mixed solution of tetraethyl orthosilicate and absolute ethanol with a volume ratio of 1:1 for aging treatment for 48 h. After the treatment is completed, the gel is taken out and placed in 200 parts of n-hexane for standing for 42 h. Finally, the treated gel is dried at 55 °C, 75 °C and 120 °C for 2 h in sequence, and finally the phosphorus-containing diol modified silica aerogel is obtained.

[0079] The preparation method of the phosphorus-containing diol in this example is as follows: By weight, 30 parts of diethyl phosphite, 22 parts of diethanolamine, 10.0 parts of paraformaldehyde and 200 parts of chloroform are successively added into a three-necked flask equipped with a condensation reflux device and a magnetic stirring device, and then stirred at 60 °C for 15 h. During the stirring process, the phosphorus-containing diol is synthesized and the solvent is removed. After the stirring is completed, it is cooled to room temperature to obtain the phosphorus-containing diol.

[0080] The preparation method of a flame-retardant sponge material in this example includes the following steps:

[0081] S1. Raw material mixing: Polyurethane, aluminum hydroxide, toluene diisocyanate, deionized water, cyclopentane, triethanolamine, dibutyltin dilaurate, epoxy soybean oil, talcum powder, antioxidant, light stabilizer Tinuvin770, pigment, antimony trioxide, expanded graphite, L-580 silicone oil and methylisothiazolinone are added to the reaction kettle according to weight parts, and then stirred at 350 rpm for 10 min. Then, the phosphorus-based flame retardant modified oxidized feather-shaped carbon nanotubes and the phosphorus-containing diol modified silica aerogel are continuously added and stirred for 20 min to obtain a uniformly dispersed mixed solution.

[0082] S2. Foaming treatment: The uniformly dispersed mixed solution obtained in step S1 is heated to 60 °C for foaming treatment for 40 min, and after the foaming treatment, it is allowed to stand for 45 min to form a preliminarily cured sponge material.

[0083] S3. Curing treatment: The sponge material preliminarily cured in S2 is dried at 70 °C, 120 °C and 180 °C for 4 h in sequence to complete curing. After the curing is completed and cooled to room temperature, a flame-retardant sponge material is obtained.

[0084] Comparative Example 1

[0085] Basically the same as Example 1, except that the oxidized feathery carbon nanotubes were not modified with dimethyl methylphosphonate.

[0086] Comparative Example 2

[0087] Basically the same as Example 1, except that the oxidized feathery carbon nanotubes were not treated by wet oxidation, but the original carbon nanotubes were used.

[0088] Comparative Example 3

[0089] Basically the same as Example 1, except that phosphorus-containing diol was not added in the preparation of phosphorus-containing diol modified silica aerogel.

[0090] Comparative Example 4

[0091] Basically the same as Example 1, except that phosphorus-based flame retardant modified oxidized feathery carbon nanotubes were not added in the preparation of the sponge.

[0092] Comparative Example 5

[0093] Basically the same as Example 1, except that phosphorus-containing diol modified silica aerogel was not added in the preparation of the sponge.

[0094] Performance Test:

[0095] The test methods for the sponge material include the limiting oxygen index method and the vertical burning method, which are used to characterize its flame retardant performance respectively. The experimental operation of the limiting oxygen index method is carried out according to the national standard "GB / T 5454-1997". In the experiment, 10 specimens with a size of 15 cm × 6 cm were prepared, and the specimens were placed in a gas mixture of oxygen and nitrogen in a certain proportion, and the combustion situation of the specimens was observed. 10 valid data were recorded, and their arithmetic mean was calculated as the limiting oxygen index of the material. The operation steps and evaluation criteria of the vertical burning method are carried out with reference to the national standard "GB / T 5455-2014". In the experiment, specimens with a size of 30 cm× 8 cm were prepared, and the specimens were fixed on the fixture for ignition test, and the behaviors during the combustion process were observed and recorded, including whether thick smoke and molten droplets were generated, the afterflame time (flaming combustion time) and the smoldering time (non-flaming combustion time) of the specimen after the ignition source was removed, and the damage length (mm) of the specimen after the combustion ended.

[0096] Detection of mechanical properties of materials: First, take sponge specimens and soak them in PBS buffer solution with a pH value of 7.4. After the samples are completely saturated with the solution and reach equilibrium, use a vernier caliper to measure and record the data of each dimension of the samples. Then, carry out compression experiments using a universal material testing system, and control the compression speed at 5 mm / min during the experiment. To protect the equipment, the maximum compression deformation is controlled within 95% during the experiment to obtain the maximum bearing pressure value. According to the measured stress-strain curve, calculate the material toughness value by the integration method, and obtain the compression modulus by dividing the stress by the strain. Each formula sample is tested in parallel 5 times, and the obtained data is expressed in the form of mean ± standard deviation (n = 5).

[0097] The properties of the sponge materials in Examples 1-4 and Comparative Examples 1-5 are summarized in Table 2.

[0098] Table 2 Summary of the properties of the sponge materials in Examples 1-4 and Comparative Examples 1-5

[0099]

[0100] In Comparative Example 1, without modification with dimethyl methylphosphonate, the phosphorus-containing groups could not be effectively grafted, thus affecting the flame retardancy performance (such as a decrease in the limiting oxygen index, afterflame time, and smoldering time). However, due to the still-existing reinforcing effect of the oxidized feather-like carbon nanotubes, its mechanical properties (such as compression strength and toughness) were only slightly lower than those of Example 1; in Comparative Example 2, using the original carbon nanotubes without wet oxidation treatment, due to poor interfacial bonding, not only the flame retardancy performance was affected, but also the mechanical properties decreased, and further decreased compared with Comparative Example 1. However, the original carbon nanotubes still had a certain reinforcing effect, so the compression strength and toughness remained at a low level; in Comparative Example 3, the lack of addition of phosphorus-containing diol affected the uniformity and effectiveness of the distribution of the flame retardant, and the flame retardancy performance decreased. However, due to the presence of the silica matrix, its mechanical properties were still close to those of the example; in Comparative Example 4, the lack of addition of phosphorus-based flame retardant modified oxidized feather-like carbon nanotubes had the greatest impact on the flame retardancy performance, especially the significant deterioration of the limiting oxygen index, afterflame time, and smoldering time. At the same time, the mechanical properties were also greatly affected, and the compression strength and toughness dropped to the lowest; in Comparative Example 5, the lack of addition of phosphorus-containing diol modified silica aerogel led to the loss of the flame retardant effect of the aerogel, and the flame retardancy performance decreased significantly. However, the basic structure was not completely damaged, and the mechanical properties were slightly better than those of Comparative Example 4.

[0101] In summary, the changes in different components have a significant impact on the flame retardancy and mechanical properties of the sponge material. The modification with dimethyl methylphosphonate can effectively graft phosphorus-containing groups, significantly improving the flame retardancy of the material; the oxidized feather-like carbon nanotubes treated by wet oxidation enhance the flame retardancy and mechanical properties of the material by improving the interfacial bonding performance; the addition of phosphorus-containing diol plays a key role in the uniformity and effectiveness of the flame retardant distribution, and also makes a significant contribution to the flame retardancy of the material; the introduction of phosphorus-based flame retardant modified oxidized feather-like carbon nanotubes significantly improves the comprehensive performance of the material, while the addition of phosphorus-containing diol modified silica aerogel further enhances the flame retardancy and mechanical properties of the material. It can be seen that the reasonable design and synergistic effect of each component are crucial for optimizing the overall performance of the material.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that any equivalent structural transformation made under the concept of the present invention by using the content of the specification and drawings of the present invention should be covered by the protection scope of the claims of the present invention.

Claims

1. A flame-retardant sponge material, characterized in that, By weight parts, it includes the following components: 3.0 - 6.5 parts of phosphorus-based flame retardant modified oxidized feather-shaped carbon nanotubes, 4.0 - 6.5 parts of phosphorus-containing diol modified silica aerogel; 90 - 110 parts of polyurethane, 20 - 30 parts of aluminum hydroxide, 1.0 - 3.0 parts of toluene diisocyanate, 1.0 - 1.5 parts of deionized water, 0.5 - 1.5 parts of cyclopentane, 0.5 - 1.5 parts of triethanolamine, 0.2 - 0.5 parts of dibutyltin dilaurate, 5 - 10 parts of epoxy soybean oil, 5 - 10 parts of talcum powder, 0.5 - 1.5 parts of antioxidant, 0.5 - 1.5 parts of light stabilizer, 0.1 - 0.5 parts of pigment, 3.0 - 5.0 parts of antimony trioxide, 5 - 8 parts of expanded graphite, 0.1 - 0.5 parts of silicone surfactant, 0.1 - 0.3 parts of isothiazolinone antibacterial agent; The phosphorus-based flame retardant modified oxidized feather-shaped carbon nanotubes are obtained by modifying oxidized feather-shaped carbon nanotubes with dimethyl methylphosphonate; The oxidized feather-shaped carbon nanotubes are obtained by wet oxidation of carbon nanotubes; The phosphorus-containing diol modified silica aerogel is obtained by chemically modifying silica aerogel with phosphorus-containing diol in the sol-gel method; The phosphorus-containing diol is prepared by the condensation reaction of diethyl phosphite, diethanolamine and paraformaldehyde; 2. A flame-retardant sponge material as claimed in claim 1, wherein, The preparation method of the phosphorus-based flame retardant modified oxidized feather-shaped carbon nanotubes is as follows: By weight parts, add 40 - 60 parts of oxidized feather-shaped carbon nanotubes, 100 - 140 parts of dimethyl methylphosphonate and 3.0 - 6.0 parts of monobutyltin oxide into a three-necked culture flask, stir at 160 - 170 °C for 24 - 36 h, after stirring, raise the temperature to 180 - 185 °C and continue to stir for 30 - 45 min to evaporate the unreacted dimethyl methylphosphonate, after evaporation, cool to room temperature to obtain phosphorus-based flame retardant modified feather-shaped carbon nanotubes.

3. A flame-retardant sponge material according to claim 1 or 2, characterized in that, The preparation method of the oxidized feather-shaped carbon nanotubes is as follows: By weight parts, mix 10 - 20 parts of carbon nanotubes, 4.0 - 8.0 parts of sodium nitrate and 200 parts of 98 wt.% sulfuric acid in an ice bath, then stir at a stirring speed of 200 - 300 rpm for 20 - 30 min, while stirring, slowly add 25 - 30 parts of potassium permanganate into the mixed solution, after stirring, stir the mixed solution in a water bath at 30 - 40 °C for 90 - 120 min, after stirring, slowly add 1000 - 1200 parts of deionized water, then continue to stir at 60 - 80 °C for 25 - 35 min to obtain a suspension, then slowly drop 30 wt.% hydrogen peroxide into the suspension, and continuously stir at a stirring speed of 200 - 300 rpm during the dropping process until the suspension turns bright yellow, then centrifuge to collect the precipitate, and wash the precipitate 3 times with 10 wt.% hydrochloric acid solution, finally dry the washed precipitate in a vacuum drying oven at room temperature for 20 - 24 h to obtain oxidized feather-shaped carbon nanotubes.

4. A flame-retardant sponge material as claimed in claim 1, wherein, The preparation method of the phosphorus-containing diol modified silica aerogel is as follows: By weight, 18-25 parts of tetraethyl orthosilicate, 45-55 parts of absolute ethanol and 10 parts of deionized water are mixed and magnetically stirred for 20-30 min, then 35-42 parts of phosphorus-containing diol are added and stirred for another 30-45 min to obtain solution A for standby; Separately, 10-20 parts of ammonium polyphosphate and 150 parts of absolute ethanol are mixed and ultrasonically treated for 45-60 min to obtain solution B, then solution B is added to the mixed solution of solution A, and then the pH of the mixed solution is adjusted to 7.5-8.0 with ammonia water. Then, the mixed solution after pH adjustment is left standing at 45-50 °C for 300-360 min to obtain a gel. Then, the gel is put into a mixed solution of 200-250 parts of tetraethyl orthosilicate and absolute ethanol with a volume ratio of 1:1 for aging treatment for 36-48 h. After the treatment is completed, the gel is taken out and put into 200 parts of n-hexane and left standing for 30-42 h. Finally, the treated gel is dried at 50-55 °C, 70-75 °C and 110-120 °C for 2 h in sequence, and finally the phosphorus-containing diol modified silica aerogel is obtained.

5. A flame-retardant sponge material according to claim 1 or 4, characterized in that The preparation method of the phosphorus-containing diol is as follows: By weight, 20-30 parts of diethyl phosphite, 18-22 parts of diethanolamine, 4.0-10.0 parts of paraformaldehyde and 200 parts of chloroform are sequentially added into a three-necked flask equipped with a condensation reflux device and a magnetic stirring device, and then stirred at 50-60 °C for 10-15 h. During the stirring process, the phosphorus-containing diol is synthesized and the solvent is removed. After the stirring is completed, it is cooled to room temperature to obtain the phosphorus-containing diol.

6. A flame-retardant sponge material according to claim 1, wherein, The light stabilizer is light stabilizer Tinuvin770 or light stabilizer Chimassorb944; The pigment is one or a mixture of titanium dioxide, iron oxide red or carbon black.

7. A flame-retardant sponge material according to claim 1, characterized in that, The silicone surfactant is DC-193 water-soluble silicone oil or L-580 silicone oil; The isothiazolinone antibacterial agent is methylisothiazolinone.

8. The preparation method of a flame-retardant sponge material as claimed in claim 1, characterized in that, It includes the following steps: S1. Raw material mixing: Polyurethane, aluminum hydroxide, toluene diisocyanate, deionized water, cyclopentane, triethanolamine, dibutyltin dilaurate, epoxy soybean oil, talcum powder, antioxidant, light stabilizer, pigment, antimony trioxide, expanded graphite, silicone surfactant and isothiazolinone antibacterial agent are added to the reaction kettle according to weight parts, and then stirred at 300-350 rpm for 5-10 min. Then, the phosphorus-based flame retardant modified oxidized feather-shaped carbon nanotubes and the phosphorus-containing diol modified silica aerogel are continuously added and stirred for 10-20 min to obtain a uniformly dispersed mixed solution; S2. Foaming treatment: The uniformly dispersed mixed solution obtained in step S1 is heated to 40-60 °C for foaming treatment for 30-45 min, and then left standing for 30-45 min after the foaming treatment to form a preliminarily cured sponge material; S3. Curing treatment: The preliminarily cured sponge material obtained in S2 is dried at 50-70 °C, 100-120 °C and 150-180 °C for 4 h in sequence to complete curing. After the curing is completed and cooled to room temperature, a flame-retardant sponge material is obtained.

9. The application of a flame-retardant sponge material as described in claim 1 in the fields of construction, household and transportation.

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