Environment-friendly flame retardant composition and preparation method thereof

Abstract

The invention provides an environment-friendly flame retardant composition and a preparation method thereof, and belongs to the technical field of flame retardants, and the environment-friendly flame retardant composition comprises the following components in parts by weight: 10-25 parts of plant-based porous carbon, 1-5 parts of hyperbranched polyborosilazane, 30-50 parts of ammonium polyphosphate and 10-20 parts of aluminum diethylphosphinate. Wherein the porous carbon is covalently connected with the hyperbranched polyborosilazane through a silane coupling agent, and the hyperbranched polyborosilazane is prepared from a monomer comprising amino silane and borane. According to the invention, the plant-based porous carbon and the hyperbranched polyborosilazane are covalently linked through the silane coupling agent, so that not only are the dispersibility and compatibility of all the components effectively improved, but also the formation of a compact carbon layer is promoted, and the thermal stability and mechanical strength of the carbon layer are enhanced. And the flame retardant is compounded with ammonium polyphosphate and aluminum diethylphosphinate, so that the condensed-phase flame retardant efficiency and the gas-phase flame retardant efficiency are further enhanced.

Description

Technical Field

[0001] This invention belongs to the field of flame retardant technology, specifically relating to an environmentally friendly flame retardant composition and its preparation method. Background Technology

[0002] Polymer materials are widely used in modern industry and daily life, but their inherent flammability poses a significant fire risk. Therefore, developing efficient flame-retardant technologies to improve the safety of polymer materials has become a key focus in this field. Halogen-free flame retardancy is an inevitable trend in current flame-retardant technology development. To meet stringent flame-retardant standards, high levels of flame retardants are typically added to materials, but this often severely impairs the mechanical, processing, and electrical properties of the substrate. To overcome this bottleneck, "synergistic flame-retardant technology" has emerged, which involves compounding flame-retardant components with different mechanisms of action to achieve high flame-retardant efficiency with low addition amounts.

[0003] In existing technologies, carbon materials (such as carbon nanotubes and graphene) have attracted widespread attention due to their unique specific surface area, thermal stability, and catalytic potential. Existing research shows that carbon materials can act as physical barriers and may play a synergistic role in condensed phases by catalyzing the crosslinking of polymers into carbon through surface functional groups.

[0004] However, despite the application potential shown by carbon materials, significant limitations remain in constructing efficient composite flame-retardant systems. First, functional synergy is limited. Traditional carbon materials struggle to simultaneously and efficiently bridge and enhance different flame-retardant mechanisms (e.g., gas-phase and condensed-phase flame retardancy). Their synergistic effect is often limited to one aspect, failing to achieve true "multi-mechanism synergy," resulting in the overall efficiency of the composite flame-retardant system falling short of expectations. Second, interfacial compatibility and dispersibility issues remain prominent. The interfacial interactions between carbon materials and the polymer matrix and other flame-retardant components are weak, making them prone to aggregation. This not only limits their synergistic function but may also lead to a decline in the material's mechanical properties. Finally, the char layer formed by carbon materials often lacks sufficient strength, density, and high-temperature stability, making it difficult to maintain a complete protective structure under intense combustion conditions. Summary of the Invention

[0005] In view of the above situation and to overcome the defects of the prior art, the purpose of the present invention is to provide an environmentally friendly flame retardant composition and its preparation method, so as to at least partially solve the problems mentioned in the background art.

[0006] The technical solution adopted in this invention is as follows: The first aspect of this invention provides an environmentally friendly flame retardant composition comprising the following components in parts by weight: The mixture comprises 10-25 parts of plant-based porous carbon, 1-5 parts of hyperbranched polyborosilicate, 30-50 parts of ammonium polyphosphate, and 10-20 parts of aluminum diethylphosphonate; wherein the porous carbon and the hyperbranched polyborosilicate are covalently linked by a silane coupling agent, and the hyperbranched polyborosilicate is prepared from monomers including aminosilane and borane.

[0007] In some embodiments of the present invention, the plant material for the plant-based porous carbon is selected from at least one of bamboo, sugarcane bagasse, rice husk, and bamboo leaves.

[0008] In some embodiments of the present invention, the silane coupling agent is selected from at least one of γ-aminopropyltriethoxysilane and γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0009] In some embodiments of the present invention, the aminosilane is selected from at least one of methylaminosilane and phenylaminosilane.

[0010] In some embodiments of the present invention, the borane is selected from at least one of tert-butylamine borane and dimethyl sulfide borane.

[0011] A second aspect of this invention provides a method for preparing an environmentally friendly flame retardant composition, comprising the following steps: Step S1: Under inert gas protection, aminosilane monomer and borane monomer are dissolved in an organic solvent and reacted at 60-120℃ for 4-12 hours to obtain hyperbranched polyborosilicate. Step S2: The plant raw materials are carbonized and activated to obtain plant-based porous carbon; Step S3: The hyperbranched polyborosilazane obtained in step S1 is pre-reacted with a silane coupling agent in the presence of a catalyst to obtain a prepolymer; then the prepolymer is mixed with the activated plant-based porous carbon obtained in step S2 and reacted at 80-100°C for 12-24 hours to obtain a hybrid material. Step S4: Mix the hybrid material obtained in step S3 with ammonium polyphosphate and aluminum diethylphosphonate in a solvent to obtain the environmentally friendly flame retardant composition.

[0012] In some embodiments of the present invention, in step S1, the molar ratio of the aminosilane monomer to the boronane monomer is 1:(0.8-1.2); the organic solvent is toluene or tetrahydrofuran.

[0013] In some embodiments of the present invention, in step S2, the carbonization process is carried out under an inert atmosphere, with the temperature increased to 400-500°C at a heating rate of 2-5°C / min, and held at that temperature for 1-3 hours.

[0014] In some embodiments of the present invention, in step S2, the activation treatment conditions include: mixing the carbonized product with KOH at a mass ratio of 1:(2-6), activating it at 600-800°C for 1-3 hours under an inert atmosphere, and then washing it with acid and water until it is neutral before drying.

[0015] In some embodiments of the present invention, in step S3, the mass ratio of the hyperbranched polyborosilazane to the silane coupling agent is 1:(0.5-1.2); the catalyst is a platinum catalyst.

[0016] The beneficial effects achieved by this invention are as follows: This invention covalently links plant-based porous carbon with hyperbranched polyborosilicates via a silane coupling agent, effectively improving the dispersibility and compatibility of the components, promoting the formation of a dense carbon layer, and enhancing the thermal stability and mechanical strength of the carbon layer. Furthermore, by compounding with ammonium polyphosphate and aluminum diethylphosphonate, it further enhances the flame retardant efficiency in both the condensed phase and the gas phase. Detailed Implementation

[0017] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to this invention. The preferred embodiments and materials described herein are for illustrative purposes only and do not limit the scope of this application.

[0019] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0020] In response to the problems raised in the background art, the first aspect of the present invention provides an environmentally friendly flame retardant composition comprising the following components in parts by weight: The mixture comprises 10-25 parts of plant-based porous carbon, 1-5 parts of hyperbranched polyborosilicate, 30-50 parts of ammonium polyphosphate, and 10-20 parts of aluminum diethylphosphonate; wherein the porous carbon and the hyperbranched polyborosilicate are covalently linked by a silane coupling agent, and the hyperbranched polyborosilicate is obtained from monomers including aminosilane and borane.

[0021] The environmentally friendly flame retardant composition provided in this invention forms a hybrid material by covalently linking plant-based porous carbon with hyperbranched polyborosilicate, and is further compounded with ammonium polyphosphate and aluminum diethylphosphonate, significantly improving the synergistic flame retardant efficiency. The hyperbranched polyborosilicate is prepared by polymerization of aminosilane monomers and boronane monomers, and its molecular structure simultaneously contains silicon, boron, and nitrogen elements. The silane coupling agent acts as a bridging molecule; its functional group at one end reacts with the oxygen-containing functional groups on the surface of the plant-based porous carbon, while its functional group at the other end bonds with the active groups in the hyperbranched polyborosilicate, thereby forming a stable chemical bond.

[0022] This combination significantly enhances flame retardant performance: First, the silane coupling agent acts as a bridging molecule. One end of its functional group undergoes a condensation reaction with oxygen-containing functional groups such as hydroxyl and carboxyl groups on the surface of plant-based porous carbon, while the other end bonds with the active groups in hyperbranched polyborosilazane. This stable chemical connection significantly improves the interfacial compatibility of the components, solves the problem of easy agglomeration in physical mixing, and improves the dispersion uniformity and stability of the flame retardant system in the polymer matrix. Second, the plant-based porous carbon provides a large specific surface area and abundant surface active sites, enabling it to adsorb pyrolysis products and provide catalytic centers. Meanwhile, the hyperbranched polyborosilazane can transform into a silicon- and boron-containing ceramic phase upon heating. This structural feature gives the hybrid material excellent thermal stability and effectively promotes cross-linking of the polymer matrix into char at high temperatures, enhancing the ability to form a char layer.

[0023] Meanwhile, the combination of ammonium polyphosphate and aluminum diethylphosphinate can form a multi-mechanism synergistic flame retardant system. In the condensed phase, the hybrid material can promote the decomposition of ammonium polyphosphate to generate polyphosphoric acid, catalyze the cross-linking of the substrate to form a denser and more stable char layer, and the ceramic phase transformed by the hybrid material itself further enhances the thermal stability and mechanical strength of the char layer; in the gas phase, the hybrid material can promote the decomposition of aluminum diethylphosphinate to release free radical scavengers, enhancing the gas phase flame retardant effect.

[0024] In summary, this invention, by covalently linking plant-based porous carbon with hyperbranched polyborosilicates via a silane coupling agent, not only effectively improves the dispersibility and compatibility of each component but also promotes the formation of a dense carbon layer, enhancing its thermal stability and mechanical strength. Furthermore, when combined with ammonium polyphosphate and aluminum diethylphosphonate, it further enhances the flame retardant efficiency in both the condensed phase and the gas phase.

[0025] In some embodiments, the plant-based porous carbon uses plant materials selected from at least one of bamboo, sugarcane bagasse, rice husk, and bamboo leaves. These natural materials are not only widely available and inexpensive, but their unique biomass structure also contributes to the formation of a rich porous structure and a large specific surface area. Porous carbon prepared from different plant materials has its own characteristics: bamboo-derived porous carbon has high mechanical strength, rice husk-based porous carbon has better thermal stability due to its silicon content, and sugarcane bagasse porous carbon has a relatively developed pore structure. This diversity in material selection allows for flexible control of the physicochemical properties of hybrid materials according to specific application requirements, further improving the economy and applicability of the technical solution while ensuring flame retardant performance.

[0026] In some embodiments, the silane coupling agent is selected from at least one of γ-aminopropyltriethoxysilane and γ-(2,3-epoxypropoxy)propyltrimethoxysilane. The amino group of γ-aminopropyltriethoxysilane can form stable chemical bonds with the active groups in hyperbranched polyborosilicates, while the epoxy group of γ-(2,3-epoxypropoxy)propyltrimethoxysilane can undergo ring-opening reactions with functional groups such as hydroxyl groups on the surface of plant-based porous carbon. This functional group matching ensures strong covalent bonds between the components in the hybrid material, significantly improving interfacial bonding strength and effectively enhancing the dispersion stability of the flame-retardant component in the polymer matrix, thus providing a reliable interfacial guarantee for constructing a highly efficient and stable multiphase flame-retardant system.

[0027] In some embodiments, the aminosilane is selected from at least one of methylaminosilane and phenylaminosilane. Methylaminosilane has high reactivity and steric adaptability, which helps to form a regular branched structure; while phenylaminosilane, with its aromatic ring structure, can not only improve the thermal stability of the polymer, but also enhance its compatibility with the polymer matrix.

[0028] In some embodiments, the borane is selected from at least one of tert-butylamine borane and dimethyl sulfide borane. Tert-butylamine borane, due to its stable complex structure, allows for controlled release of boron during the reaction, which is beneficial for forming a structurally regular polymer; while dimethyl sulfide borane has high reactivity and can promote the polymerization process.

[0029] A second aspect of this invention provides a method for preparing an environmentally friendly flame retardant composition, comprising the following steps: Step S1: Under inert gas protection, aminosilane monomer and boronane monomer are dissolved in an organic solvent and reacted at 60-120℃ for 4-12 hours. After precipitation, washing and drying, hyperbranched polyborosilicate is obtained. Step S2: The plant raw materials are carbonized and activated to obtain plant-based porous carbon; Step S3: The hyperbranched polyborosilazane obtained in step S1 is pre-reacted with a silane coupling agent in the presence of a catalyst to obtain a prepolymer; then the prepolymer is mixed with the activated plant-based porous carbon obtained in step S2 and reacted at 80-100°C for 12-24 hours to obtain a hybrid material. Step S4: The hybrid material obtained in step S3 is mixed with ammonium polyphosphate and aluminum diethylphosphinate in a solvent, and after dispersion and drying, an environmentally friendly flame retardant composition is obtained.

[0030] In step S1, hyperbranched polyborosilicate is synthesized under controlled temperature and time conditions under inert gas protection, ensuring the regularity of the polymer structure and thermal stability. In step S2, plant-based porous carbon with rich pore structure and surface active sites is prepared by carbonizing and activating plant raw materials. In step S3, through pre-reaction and subsequent mixing reaction, the hyperbranched polyborosilicate forms a stable chemical bond with the plant-based porous carbon through a silane coupling agent, effectively improving interfacial compatibility. In step S4, the obtained hybrid material is uniformly dispersed by solution mixing with ammonium polyphosphate and aluminum diethylphosphonate, finally obtaining a composition with synergistic flame retardant effect through multiple mechanisms.

[0031] In some embodiments, in step S1, the molar ratio of aminosilane monomer to borane monomer is 1:(0.8-1.2); the organic solvent is toluene or tetrahydrofuran. The 1:(0.8-1.2) molar ratio range allows both monomers to fully participate in the polymerization process, avoiding side reactions caused by excess borane and preventing structural defects caused by excess aminosilane, thus facilitating the formation of well-structured hyperbranched polymers. Toluene and tetrahydrofuran, as reaction media, not only provide a suitable dissolution environment and reaction temperature range for the polymerization reaction but also effectively promote the mass transfer process of the reactants, ensuring the homogeneity and integrity of the polymerization reaction.

[0032] In some embodiments, in step S2, the carbonization process involves heating to 400-500°C at a rate of 2-5°C / min under an inert atmosphere and holding at that temperature for 1-3 hours. This specific heating rate and temperature range ensures that the plant material undergoes thorough and orderly carbonization during pyrolysis, avoiding the violent release of volatile components and damage to the carbon skeleton structure caused by excessively rapid heating, while guaranteeing the effective decomposition of organic components and the initial formation of the carbon structure. Controlling the holding time provides the necessary time to ensure the full completion of the carbonization process, contributing to the formation of a structurally stable carbon precursor.

[0033] In some embodiments, the activation treatment conditions in step S2 include: mixing the carbonized product with KOH at a mass ratio of 1:(2-6), activating at 600-800°C for 1-3 hours under an inert atmosphere, followed by acid washing, water washing until neutral, and drying. This specific combination of alkali-to-carbon ratio, activation temperature, and time range effectively promotes selective etching of the carbon skeleton and directional development of pore structures. The higher KOH ratio helps to form a rich microporous structure, while the suitable temperature range ensures that the activation reaction proceeds fully without excessive ablation.

[0034] In some embodiments, in step S3, the mass ratio of hyperbranched polyborosilicate to silane coupling agent is 1:(0.5-1.2); the catalyst is a platinum catalyst. Establishing this mass ratio range ensures that the silane coupling agent can adequately encapsulate the surface active sites of the hyperbranched polyborosilicate without causing side reactions due to excessive use. Furthermore, the platinum catalyst can improve the efficiency and selectivity of the grafting reaction.

[0035] The present invention will be further described below by way of specific embodiments.

[0036] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods already existing in the art; unless otherwise specified, the experimental materials used in the following embodiments are all purchased from commercial channels.

[0037] Example 1: S1. Under nitrogen protection, methylaminosilane and boron dimethyl sulfide were dissolved in toluene at a molar ratio of 1:1 and reacted at 60°C for 12 hours. After the reaction was completed, the mixture was precipitated with ethanol, washed, and dried under vacuum at 60°C for 12 hours to obtain a white powdery hyperbranched polyborosilicate.

[0038] S2. After crushing the bamboo, carbonize it at 400℃ for 3 hours under a nitrogen atmosphere by heating at 2℃ / min. Mix the carbonized product with KOH at a mass ratio of 1:2 and activate it at 600℃ for 1 hour under a nitrogen atmosphere. Wash the product with hydrochloric acid and water until neutral, and dry it at 80℃ to obtain bamboo-based porous carbon.

[0039] S3. Mix 1 part by weight of hyperbranched polyborosilazane and γ-aminopropyltriethoxysilane at a mass ratio of 1:0.5, add isopropanol chloroplatinic acid solution (platinum content 50 ppm), and pre-react at 70°C for 2 hours. Then add 10 parts of bamboo-based porous carbon and react at 80°C for 24 hours to obtain the hybrid material.

[0040] S4. Mix the hybrid material, 30 parts of ammonium polyphosphate and 10 parts of aluminum diethylphosphonate in ethanol, ultrasonically disperse for 2 hours, and dry at 80°C to obtain an environmentally friendly flame retardant composition.

[0041] Example 2: S1. Under nitrogen protection, phenylaminosilane and borane tert-butylamine were dissolved in tetrahydrofuran at a molar ratio of 1:1.2 and reacted at 120°C for 4 hours. After the reaction was completed, the mixture was precipitated with ethanol, washed, and dried under vacuum at 60°C for 12 hours to obtain a white powdery hyperbranched polyborosilicate.

[0042] S2. After crushing the rice husks, carbonize them at 500℃ for 1 hour under a nitrogen atmosphere by heating at 5℃ / min. Mix the carbonized product with KOH at a mass ratio of 1:6 and activate it at 800℃ for 1 hour under a nitrogen atmosphere. Wash the product with hydrochloric acid and water until neutral, and dry it at 80℃ to obtain bamboo-based porous carbon.

[0043] S3. Mix 5 parts by weight of hyperbranched polyborosilazane and γ-aminopropyltriethoxysilane at a mass ratio of 1:1.2, add isopropanol chloroplatinic acid solution (platinum content 50 ppm), and pre-react at 95°C for 2 hours. Then add 25 parts by weight of bamboo-based porous carbon, and react at 100°C for 12 hours to obtain the hybrid material.

[0044] S4. Mix the hybrid material, 50 parts of ammonium polyphosphate and 20 parts of aluminum diethylphosphonate in ethanol, ultrasonically disperse for 2 hours, and dry at 80°C to obtain an environmentally friendly flame retardant composition.

[0045] Example 3: The only difference from Example 1 is: Rice husks were used as the plant material, and the activation temperature was 650℃. Hyperbranched polyborosilicates were synthesized using phenylaminosilane and borothane tert-butylamine in a molar ratio of 1:0.9. Flame retardant composition ratio: 15 parts plant-based porous carbon, 3 parts hyperbranched polyborosilazane, 40 parts ammonium polyphosphate, and 15 parts aluminum diethylphosphonate.

[0046] Example 4: The only difference from Example 1 is: Sugarcane bagasse was used as the plant material, with a KOH ratio of 1:5 and an activation temperature of 750℃. γ-(2,3-epoxypropoxy)propyltrimethoxysilane was used as a coupling agent; Flame retardant composition ratio: 20 parts plant-based porous carbon, 2 parts hyperbranched polyborosilicate, 45 parts ammonium polyphosphate, and 18 parts aluminum diethylphosphonate.

[0047] Example 5: The only difference from Example 1 is: Bamboo leaves were used as the plant material, and the carbonization temperature was 420℃. The molar ratio of aminosilane to borane is 1:1.2, and the reaction temperature is 90℃. Flame retardant composition ratio: 18 parts plant-based porous carbon, 4 parts hyperbranched polyborosilicate, 35 parts ammonium polyphosphate, and 12 parts aluminum diethylphosphonate.

[0048] Example 6: The only difference from Example 1 is: The raw material is a mixture of bamboo and rice husks (1:1). Use a mixture of methylaminosilane and phenylaminosilane (1:1); Flame retardant composition ratio: 22 parts plant-based porous carbon, 2.5 parts hyperbranched polyborosilicate, 42 parts ammonium polyphosphate, and 16 parts aluminum diethylphosphonate.

[0049] Comparative Example 1: The only difference from Example 1 is that hyperbranched polyborosilicate is not added; only physically mixed bamboo-based porous carbon, ammonium polyphosphate, and aluminum diethylphosphinate are used.

[0050] Comparative Example 2: The only difference from Example 1 is that no coupling agent is used for chemical bonding; instead, the hyperbranched polyborosilicate is directly and physically mixed with other components.

[0051] Test method: The prepared flame retardant was added to the epoxy resin at an addition amount of 20 wt% to prepare a flame retardant epoxy resin composite material.

[0052] Limiting Oxygen Index (LOI): The limiting oxygen index test was conducted according to GB / T 2406-2009 standard using an HC-2C oxygen index analyzer. The sample size was 130×6.5×3 mm³. The test determined the minimum oxygen concentration required to maintain stable combustion in a nitrogen-oxygen mixture. The test results are shown in Table 1.

[0053] Vertical flammability rating: The vertical flammability test is conducted according to ANSI / UL 94-2010 standard, using a CZF-3 horizontal and vertical flammability tester. The sample size is 125×13×3mm. 3 The afterflame time, dripping phenomenon, and whether the absorbent cotton was ignited were recorded by applying a flame for 10 seconds twice. The test results are shown in Table 1.

[0054] Carbon residue test: Thermogravimetric analysis was performed using a TG 209 F1 Iris thermogravimetric analyzer under a nitrogen atmosphere, with the temperature increased from 40℃ to 800℃ at a rate of 20℃ / min. All tests were conducted under standard conditions of 23±2℃ and 50±5% relative humidity. The test results are shown in Table 1.

[0055] Table 1

[0056] Referring to the test results in Table 1, the limiting oxygen index (LOI) of all embodiments exceeded 30%, and all passed the UL-94 V-0 rating, indicating that all embodiments of the present invention within the scope of the claims can achieve highly efficient flame retardancy. Comparative Example 1 had an LOI of only 25.8%, and only reached the V-1 rating, which fully demonstrates the important role of hyperbranched polyborosilazane in the flame retardant system. Comparative Example 2 had an LOI of 27.1%, which was better than Comparative Example 1, but still significantly lower than all other embodiments, indicating that chemical bonding treatment has a significant impact on improving flame retardant performance.

[0057] The carbon residue rate of Example 1 was 31.2%, which was significantly higher than that of Comparative Example 1 and Comparative Example 2. Hyperbranched polyborosilicate was converted into a silicon boron carbon oxide ceramic phase at high temperature and filled into the voids of the carbon layer, which enhanced the density and thermal stability of the carbon layer. Furthermore, chemical bonding treatment can further improve the carbon residue rate.

[0058] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0059] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the protection scope of the present invention.

Claims

1. An environmentally friendly flame retardant composition, characterized in that, The components include the following parts by weight: The mixture comprises 10-25 parts of plant-based porous carbon, 1-5 parts of hyperbranched polyborosilicate, 30-50 parts of ammonium polyphosphate, and 10-20 parts of aluminum diethylphosphonate; wherein the porous carbon and the hyperbranched polyborosilicate are covalently linked by a silane coupling agent, and the hyperbranched polyborosilicate is prepared from monomers including aminosilane and borane.

2. The environmentally friendly flame retardant composition according to claim 1, characterized in that, The plant-based porous carbon uses plant materials selected from at least one of bamboo, sugarcane bagasse, rice husk, and bamboo leaves.

3. The environmentally friendly flame retardant composition according to claim 1, characterized in that, The silane coupling agent is selected from at least one of γ-aminopropyltriethoxysilane and γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

4. The environmentally friendly flame retardant composition according to claim 1, characterized in that, The aminosilane is selected from at least one of methylaminosilane and phenylaminosilane.

5. The environmentally friendly flame retardant composition according to claim 1, characterized in that, The borane is selected from at least one of borane tert-butylamine and borane dimethyl sulfide.

6. A method for preparing an environmentally friendly flame retardant composition according to any one of claims 1-5, characterized in that, Includes the following steps: Step S1: Under inert gas protection, aminosilane monomer and borane monomer are dissolved in an organic solvent and reacted at 60-120℃ for 4-12 hours to obtain hyperbranched polyborosilicate. Step S2: The plant raw materials are carbonized and activated to obtain plant-based porous carbon; Step S3: The hyperbranched polyborosilazane obtained in step S1 is pre-reacted with a silane coupling agent in the presence of a catalyst to obtain a prepolymer; then the prepolymer is mixed with the activated plant-based porous carbon obtained in step S2 and reacted at 80-100°C for 12-24 hours to obtain a hybrid material. Step S4: The hybrid material obtained in step S3 is mixed with ammonium polyphosphate and aluminum diethylphosphinate in a solvent to obtain the environmentally friendly flame retardant composition.

7. The preparation method according to claim 6, characterized in that, In step S1, the molar ratio of the aminosilane monomer to the boron monomer is 1:(0.8-1.2); the organic solvent is toluene or tetrahydrofuran.

8. The preparation method according to claim 6, characterized in that, In step S2, the carbonization process involves heating the temperature to 400-500°C at a rate of 2-5°C / min under an inert atmosphere and holding it at that temperature for 1-3 hours.

9. The preparation method according to claim 6, characterized in that, In step S2, the activation treatment conditions include: mixing the carbonized product with KOH at a mass ratio of 1:(2-6), activating it at 600-800℃ for 1-3 hours under an inert atmosphere, and then drying it after acid washing, water washing until neutral.

10. The preparation method according to claim 6, characterized in that, In step S3, the mass ratio of the hyperbranched polyborosilazane to the silane coupling agent is 1:(0.5-1.2); the catalyst is a platinum catalyst.

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