Triazinyl phosphorus and silicon-containing reactive intumescent flame retardant as well as preparation method and application thereof

Abstract

The invention discloses a triazinyl phosphorus and silicon-containing reactive intumescent flame retardant as well as a preparation method and application thereof, and the flame retardant is prepared by taking melamine, a phosphoryl chloride-containing reagent, a chlorosilane-containing reagent, phosphorus oxychloride and organic polyamine as raw materials through multi-step substitution reaction. A triazine ring, multi-oxidation-state phosphorus and an active silicon group are creatively integrated into a single molecule. The design breaks through the bottlenecks that a traditional blended flame retardant is easy to migrate, poor in synergism and capable of damaging the mechanical property of a matrix, and synergistic improvement of flame retardance and performance is achieved. Meanwhile, through a flexible molecular mechanism of the flame retardant, the material is endowed with excellent flame retardance (such as high LOI and UL-94 V-0), and meanwhile, good mechanical strength and toughness are kept. The flame retardant is simple in synthesis process, easy in product purification, high in yield and easy for industrial production.

Description

Technical Field

[0001] This invention belongs to the field of flame retardant technology, specifically relating to a triazine-based phosphorus- and silicon-containing reactive intumescent flame retardant, its preparation method, and its application. Background Technology

[0002] Epoxy resin (EP) is widely used in key defense and national economic sectors such as electronic packaging, aerospace, composite materials, and building coatings due to its excellent dielectric properties, mechanical strength, and chemical corrosion resistance. However, its intrinsic limiting oxygen index (LOI) is only about 20%, making it a highly flammable material. It is extremely easy to ignite in air and spreads rapidly with intense flames. During combustion, it releases large amounts of smoke and toxic gases (such as CO and phenolic compounds), significantly increasing the fire hazard and seriously threatening personnel safety and the environment. Therefore, improving the flame retardant and smoke-suppressing properties of epoxy resin is a core prerequisite for realizing its high-end applications.

[0003] In recent years, intumescent flame retardant systems composed of phosphoric acid sources, nitrogen sources, and carbon sources have been widely used in the flame retardant modification of EP materials due to their high flame retardant performance, low smoke and toxic gas emissions, and excellent anti-dripping effect. However, compound intumescent flame retardants are generally mixed into the matrix through physical means, which easily leads to problems with dispersion and compatibility. During long-term service, they are also affected by environmental factors such as temperature and humidity, and may precipitate or deteriorate, resulting in uneven distribution, imbalance, and low synergistic efficiency of acid, carbon, and gas sources. Reactive flame retardants, on the other hand, are fixed into the molecular structure of EP materials through covalent bonds, ensuring the long-term stability of the flame retardant performance and reducing the impact on the mechanical properties of EP materials. Monomolecular intumescent flame retardants integrate multiple flame retardant units such as acid and gas sources into a single molecule, which can enhance the synergistic flame retardant effect of multiple flame retardant units at the molecular level, which is conducive to further improving the overall performance of the flame retardant and reducing the release of toxic fumes. However, existing reactive single-molecule intumescent flame retardants suffer from several drawbacks. Firstly, they contain a low number of active hydrogen atoms that react with epoxy groups, easily damaging the cross-linked network structure and flexibility of epoxy resin materials. Secondly, they lack diverse flame-retardant units, often consisting of combinations of phosphorus-nitrogen or phosphorus-silicon compounds. Research on the development of flame retardants with multiple flame-retardant mechanisms and their synergistic effects on epoxy resin material performance is lacking. Multifunctional flame retardants combining nitrogen-rich triazine, silicon, phosphorus, and polyamine curing units are yet to be found. Therefore, integrating multiple functional units into flame retardants through molecular structure design, reducing preparation costs, and achieving synergistic enhancement of the flame-retardant and mechanical properties of epoxy resin materials is crucial for developing high-performance, environmentally friendly flame retardants and promoting the use of epoxy resin in high-end applications. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to design and develop a novel environmentally friendly, high-performance flame retardant that combines a gas-source triazine structure with both condensed-phase and gas-phase flame-retardant effects, a multi-phosphorus oxidized state, silicon-containing flame-retardant units, and a curing unit amine group. This flame retardant can be applied to EP (Extended Polymer), reducing the amount of flame retardant required and synergistically enhancing the flame-retardant and mechanical properties of EP materials.

[0005] The specific molecular construction strategy is as follows: Electrophilic reagents with high reactivity, O=P-Cl (phosphoryl chloride) or Si-Cl (chlorosilane-containing reagent), are sequentially electrophilicly substituted with NH2 in melamine molecules under alkaline conditions to form a molecular structure with a triazine structure as the core, containing phosphorus, silicon, and nitrogen flame-retardant elements, and O=P-Cl as the reaction site. Further, the highly reactive O=P-Cl (phosphoryl chloride) undergoes a nucleophilic substitution reaction with the polyamine structure to form a polyamine flame-retardant macromolecule that can react with the epoxy structure. In addition, by adjusting the molecular structure containing O=P-Cl, different oxidation states of phosphorus can be introduced into the flame retardant, providing a new path for constructing reactive flame retardants with triazine as the core structure containing different functional flame-retardant units. Further experimental optimization and screening identify flame retardants containing multiple phosphorus oxidation states, which, while ensuring good mechanical properties of the EP composite material, exhibit optimal flame-retardant performance.

[0006] Another object of the present invention is to provide a method for preparing the above-mentioned flame retardant.

[0007] The present invention also provides the application of the above-mentioned flame retardant in modified epoxy resins, including but not limited to transportation, textiles, power, construction and other fields.

[0008] To achieve the above objectives, the present invention is implemented through the following technical solution: In a first aspect, the present invention provides a triazine-based phosphorus- and silicon-containing reactive intumescent flame retardant. This reactive intumescent flame retardant comprises a polyphosphorus oxidized state and a monophosphorus oxidized state, and its structural formula is as follows: 1) When the structure is in the polyphosphorus oxidation state: 2) When the structure is in the single phosphorus oxidation state: Where p is an integer ≥ 0; R is phenyl, methyl, ethyl, or propyl; R1 is phenyl, methyl, ethyl, or propyl; R2 is either -NH- or -CH2-.

[0009] Secondly, the present invention provides a method for preparing the above-mentioned triazine-based phosphorus- and silicon-containing reactive intumescent flame retardant: 1) When the flame retardant structure is in the polyphosphorus oxidized state, the following steps are included: (1) Melamine was added to pyridine, mixed well, phosphoric acid chloride reagent was added, mixed well, and then the temperature was raised to react, and the reaction system of intermediate product ① was obtained. (2) Dissolve the chlorosilane reagent in pyridine, mix well, and add it to the reaction system of intermediate product ①. Heat the mixture to carry out the reaction and obtain intermediate product ②. (3) Dissolve intermediate product ② in a certain amount of phosphorus oxychloride according to the proportion, and react at 100~120℃ for a set time to obtain intermediate product ③; (4) Add intermediate product ③ and organic base to the first solvent in proportion, mix well, add organic polyamine to it at -3~3℃, heat to 20~40℃, and set reaction time to obtain triazine-based reactive intumescent flame retardant MTNPPSi containing polyphosphorus oxidation state and silicon.

[0010] The first solvent acts solely as a solvent in the reaction system, dissolving the reactants and providing an environment for their interaction.

[0011] In some embodiments, in step (1), a phosphorus chloride-containing reagent is added at -3 to 3°C; the phosphorus chloride-containing reagent is any one of diphenyl chlorophosphate, dimethyl chlorophosphate, diethyl chlorophosphate, etc., or a mixture thereof; the mass ratio of melamine to pyridine is 1:30-60. The molar ratio of melamine to the phosphorus chloride-containing reagent is 1:0.5-1.5; the reaction is carried out at 20 to 40°C for 12 to 18 hours.

[0012] The chemical structural formula of the above intermediate product ① is as follows: ; Wherein, R is phenyl, methyl, ethyl or propyl.

[0013] In some embodiments, in step (2), the chlorinated silane reagent is any one or a mixture of tert-butyldimethylchlorosilane, tert-butyldiphenylchlorosilane, triisopropylchlorosilane, and triphenylchlorosilane. The chlorinated silane reagent is added to the reaction system of intermediate product ① at -3 to 3°C. The molar ratio of intermediate product ① to chlorinated silane reagent is 1:0.5-1.5. The reaction is carried out at 20 to 40°C for 8 to 16 hours.

[0014] Preferably, in step (1), the molar ratio of melamine to phosphoric acid-containing reagent can be: 1:0.5; 1:1; 1:1.5; most preferably, the molar ratio of melamine to phosphoric acid-containing reagent is 1:1.

[0015] In some embodiments, the mass ratio of melamine to pyridine is 1:30-60; preferably, it can be 1:30; 1:35; 1:40; 1:45; 1:50; 1:55; 1:60.

[0016] In step (2), the molar ratio of melamine to chlorosilane reagent can be: 1:0.5; 1:1; 1:1.5; the most preferred molar ratio of melamine to chlorosilane reagent is 1:1.

[0017] The chemical structural formula of the above intermediate product ② is as follows: .

[0018] R1 is phenyl, methyl, ethyl, or propyl.

[0019] In some embodiments, in step (3), the molar ratio of intermediate product ② to phosphorus oxychloride is 1:20-50; preferably, it can be: 1:20; 1:25; 1:30; 1:35; 1:40; 1:45; 1:50; most preferably, the molar ratio of intermediate product ② to phosphorus oxychloride is 1:40-45.

[0020] In some embodiments, in step (3), the reaction is carried out at 100~120℃ for 8-16 hours.

[0021] The intermediate product ③ has the following chemical structural formula: ; Wherein, R is phenyl, methyl, ethyl or propyl; R1 is phenyl, methyl, ethyl or propyl.

[0022] In some embodiments, in step (4), the first solvent is selected from dioxane, tetrahydrofuran, acetonitrile, ethyl acetate, acetone, or toluene; the organic polyamine is any one or a mixture of pentaethylenehexamine, tetraethylenepentamine, triethylenetetramine, diethylenetriamine, ethylenediamine, 1,4-diaminobutane, 1,6-hexanediamine, 1,7-heptanediamine, or ethylenediamine, butanediamine, 6-hexanediamine, 7-heptanediamine, and 10-decanediamine. The organic base is triethylamine, N,N - any one of diisopropylethylamine, pyridine, etc., or a mixture thereof.

[0023] In some embodiments, in step (4), the molar ratio of intermediate product ③ to organic polyamine is 1:1; the molar ratio of intermediate product ③ to organic base is 1:2-4; organic polyamine is added at -3~3℃; the reaction is carried out at 20~40℃ for 12-18h. The triazine-based phosphorus- and silicon-containing reactive intumescent flame retardant prepared by this invention, when the flame retardant structure is in the polyphosphorus oxidized state, has the following preparation reaction process: R2 is either -NH- or -CH2-.

[0024] 2) When the flame retardant structure is in the single phosphorus oxidation state, the specific steps include: (a) Melamine was added to pyridine, mixed well, and a chlorosilane reagent was slowly added dropwise at -3~3℃. The temperature was raised to 20~40℃, and the reaction was carried out for a set time to obtain intermediate product ④. (b) Dissolve intermediate product ④ in a certain amount of phosphorus oxychloride in proportion, react at 100~120℃ for a set time to obtain intermediate product ⑤; (c) Add intermediate product ⑤ and organic base to the first solvent in proportion, mix well, add organic polyamine, heat and react to obtain triazine-based reactive intumescent flame retardant TNPPSi containing monophosphorus oxidation state and silicon.

[0025] Specifically: In some embodiments, in step (a), the molar ratio of melamine to chlorosilane reagent is 1:1-3; preferably, the molar ratio can be 1:1.5; 1:2; 1:3; most preferably, the molar ratio of melamine to chlorosilane reagent is 1:2.

[0026] In some embodiments, in step (a), the chemical structural formula of the intermediate product ④ is: ; R1 is phenyl, methyl, ethyl or propyl.

[0027] In some embodiments, in step (b), the chemical structural formula of the intermediate product ⑤ is: ; R1 is phenyl, methyl, ethyl or propyl.

[0028] Other reaction materials and conditions are the same as above.

[0029] In some embodiments, in step (c), the molar ratio of intermediate product ⑤ to organic base is 1:2-4; the molar ratio of intermediate product ⑤ to organic polyamine is 1:1; the reaction is carried out at 20~40℃ for 12-18h.

[0030] Thirdly, the present invention also provides the application of the above-mentioned reactive intumescent flame retardant in modified epoxy resin.

[0031] Fourthly, the present invention also provides a flame-retardant modified epoxy resin, comprising an epoxy resin matrix and the above-mentioned reactive intumescent flame retardant incorporated therein.

[0032] In some embodiments, the preparation method of the flame-retardant modified epoxy resin includes the following steps: Epoxy resin is heated to 100-115℃ and MTNPPSi or TNPPSi flame retardant is added. The mixture is stirred evenly and vacuumed to remove air bubbles, thus obtaining a primary mixture. Add the curing agent to the primary mixture, stir evenly, and remove air bubbles by vacuuming to obtain the secondary mixture.

[0033] Preferably, the process further includes injecting the flame-retardant modified epoxy resin into a mold to prepare the target component.

[0034] A further preferred method for heating and curing the target component is as follows: after curing at 80°C for 2 hours, the temperature is raised to 150°C for 6 hours, and then the component is allowed to cool naturally to room temperature after curing.

[0035] Fifthly, the present invention provides the flame-retardant modified epoxy resin for use in transportation, textiles, power, construction and other fields.

[0036] The beneficial effects achieved by one or more embodiments of the present invention described above are as follows: The triazine-based phosphorus- and silicon-containing reactive intumescent flame retardant provided by this invention innovatively integrates the triazine ring, polyphosphorus oxidation state, and active silicon groups into the same molecular framework, creating a novel single-component flame retardant system that combines high-efficiency flame retardancy in both the gas and condensed phases and can covalently bond with EP. This design overcomes the core bottlenecks of traditional physically blended flame retardants, such as easy migration, poor synergy, and damage to mechanical properties, achieving a synergistic improvement in flame retardant efficiency and material properties.

[0037] The triazine-based phosphorus and silicon reactive intumescent flame retardant provided by this invention, at high temperatures, decomposes the triazine structure to release inert gases, diluting combustibles and promoting the expansion of the char layer; multi-oxide-state phosphorus undergoes stepwise catalytic dehydration to form char and generates PO· quenching free radicals, achieving gas-solid two-phase flame retardancy; active silicon promotes the formation of a denser and more stable silicon-carbon ceramic layer, enhancing heat insulation and oxygen barrier properties. Furthermore, this flame retardant directly participates in EP curing crosslinking through reactive groups, permanently anchoring itself in the resin network in the form of covalent bonds, fundamentally solving the performance degradation problem caused by flame retardant precipitation.

[0038] Its core advantages lie in the following: at high temperatures, the triazine structure rapidly decomposes, generating inert gases such as nitrogen and ammonia to dilute combustibles and expand the char layer; simultaneously, phosphorus elements in different oxidation states play a phased role, catalyzing polymer dehydration to char and generating PO· with free radical quenching effects, achieving gas-solid dual-phase flame retardancy; while the active silicon groups not only promote the formation of a more stable and dense silicon-carbon composite ceramic layer in the solidified phase, greatly improving the heat insulation and oxygen barrier properties of the char layer, but more importantly, the reactive sites in the flame retardant directly participate in the curing and cross-linking network of EP, permanently "anchoring" the flame retardant components to the resin skeleton in the form of covalent bonds. This essential combination fundamentally avoids the precipitation of flame retardants during use, ensuring the durability of flame retardant performance and eliminating the plasticizing effect caused by the addition of small molecule flame retardants. Ultimately, the material achieves excellent flame retardancy (such as high limiting oxygen index, UL-94 V-0 rating) while retaining or even enhancing its original mechanical strength and toughness.

[0039] The flame retardant preparation method provided by this invention has a simple synthesis process, easy post-processing such as product purification, a product yield of over 90%, and is easy to control and industrialize. Attached Figure Description

[0040] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0041] Figure 1 These are the test results for the impact resistance of EP composite materials.

[0042] Figure 2 The results are the tensile strength test results for EP composite materials.

[0043] Figure 3 The results show the flexural strength test results of EP composite materials. Detailed Implementation

[0044] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0045] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the scope of protection of the present invention.

[0046] Example 1 (1) Preparation of intermediate product ① 12.61 g of melamine was added to 800 mL of dry pyridine and stirred thoroughly to dissolve. 26.86 g of diphenyl chlorophosphate was slowly added dropwise under an ice bath. After the addition was complete, the reaction was carried out at room temperature for 12 h. After the reaction was completed, no treatment was required to obtain intermediate product ① and the reaction system.

[0047] The chemical structural formula of intermediate product ① is as follows: The product ① prepared in this embodiment was subjected to... 1 ¹H NMR (400 MHz, DMSO-d6) NMR spectrum analysis. The peak values ​​δ (ppm) correspond to the following values: δ 10.58 (¹H), 7.22-7.39 (¹⁰H), 6.4 (¹⁴H), which is consistent with the chemical environment of H in product ①.

[0048] (2) Preparation of intermediate product ② 29.49 g of triphenylchlorosilane was fully dissolved in 30 ml of pyridine and slowly added dropwise to the reaction system of intermediate product ① under ice bath. After the addition was complete, the reaction was carried out at room temperature for 12 h. The pyridine was removed by rotary evaporation, neutralized with 100 ml of saturated sodium bicarbonate solution, filtered to obtain a solid, and washed three times with distilled water. The solid was recrystallized with a mixed solvent of pyridine and water (1.5:1) to obtain intermediate product ②, which was further dried under vacuum at 60 °C with a yield of 94%.

[0049] The chemical structural formula of intermediate product ② is as follows: The product ② prepared in this embodiment was subjected to... 1 ¹H NMR (400 MHz, DMSO-d6) NMR spectrum analysis. The peak values ​​δ (ppm) correspond to the following values: δ 10.58 (¹H), 7.49-7.52 (⁶H), 7.22-7.39 (¹⁹H), 6.42 (²H), 5.49 (¹H), which is consistent with the chemical environment of H in product ②.

[0050] (3) Preparation of intermediate product ③ 30.81 g of intermediate product ② was added to 300 ml of phosphorus oxychloride, and stirred and refluxed at 110 °C for 12 h. After the reaction was completed, the excess phosphorus oxychloride was evaporated to dryness to obtain intermediate product ③, with a yield of 99%.

[0051] The chemical structural formula of intermediate product ③ is as follows: The intermediate product ③ prepared in this embodiment is subjected to... 1¹H NMR (400 MHz, DMSO-d6) NMR spectrum analysis. The peak values ​​δ (ppm) correspond to the following values: 10.58 (¹H), 9.47 (¹H), 7.49-7.52 (6H), 7.22-7.39 (¹⁹H), 5.49 (¹H), which is consistent with the chemical environment of H in intermediate ③.

[0052] (4) Preparation of product MTNPPSi-1 36.61 g of intermediate product ③ and 10.12 g of triethylamine were added to 500 ml of dioxane and stirred until homogeneous. 5.16 g of diethylenetriamine was slowly added dropwise under ice bath conditions. After the addition was complete, stirring was continued at room temperature for 18 h. After the reaction was complete, the solid was filtered to obtain the product MTNPPSi-1, which was washed with distilled water and dried to give the product MTNPPSi-1, with a yield of 94%.

[0053] The chemical structural formula of MTNPPSi-1 is as follows: The product MTNPPSi-1 prepared in this embodiment was subjected to... 1 ¹H NMR (400 MHz, DMSO-d6) NMR spectroscopy analysis. The peak values ​​(ppm) are as follows: 10.58, 10.21, 7.52-7.49, 7.36-7.39, 7.33-7.28, 7.26-7.22, 5.49, 4.71, 3.28, 2.8, 2.78, 2.71. This is consistent with the chemical environment of H in the product MTNPSi-1.

[0054] Example 2 (1) Preparation of intermediate product ① 12.61 g of melamine was added to 800 mL of dry pyridine and stirred thoroughly to dissolve. 26.86 g of diphenyl chlorophosphate was slowly added dropwise under an ice bath. After the addition was complete, the reaction was carried out at room temperature for 16 h. After the reaction was completed, no further treatment was required to obtain intermediate product ① and the reaction system. (2) Preparation of intermediate product ② 29.49 g of triphenylchlorosilane was fully dissolved in 30 ml of pyridine and slowly added dropwise to the reaction system of intermediate product ① under ice bath. After the addition was complete, the reaction was carried out at room temperature for 12 h. The pyridine was removed by rotary evaporation, neutralized with 100 ml of saturated sodium bicarbonate solution, filtered to obtain a solid, and washed three times with distilled water. The solid was recrystallized with a mixed solvent of pyridine and water (1.5:1) to obtain intermediate product ②, which was further dried under vacuum at 70 °C with a yield of 96%. (3) Preparation of intermediate product ③ 30.81 g of intermediate product ② was added to 250 ml of phosphorus oxychloride, and stirred and refluxed at 110 °C for 12 h. After the reaction was completed, the excess phosphorus oxychloride was evaporated to dryness to obtain intermediate product ③, with a yield of 99%.

[0055] (4) Preparation of product MTNPPSi-1 36.61 g of intermediate product ③ and 10.12 g of triethylamine were added to 500 ml of dioxane and stirred until homogeneous. 5.16 g of diethylenetriamine was slowly added dropwise under ice bath conditions. After the addition was complete, stirring was continued at room temperature for 18 h. After the reaction was complete, the solid was filtered to obtain the product MTNPPSi-1, which was washed with distilled water and dried to give the product MTNPPSi-1, with a yield of 94%.

[0056] Example 3 (1) Preparation of intermediate product ① 12.61 g of melamine was added to 800 mL of dry pyridine and stirred thoroughly to dissolve. 26.86 g of diphenyl chlorophosphate was slowly added dropwise under an ice bath. After the addition was complete, the reaction was allowed to proceed at room temperature for 12 h. No further treatment was required after the reaction was completed.

[0057] (2) Preparation of intermediate product ② 29.49 g of triphenylchlorosilane was fully dissolved in 30 ml of pyridine and slowly added dropwise to the reaction system of intermediate product ① under ice bath. After the addition was complete, the reaction was carried out at room temperature for 16 h. The pyridine was removed by rotary evaporation, neutralized with 100 ml of saturated sodium bicarbonate solution, filtered to obtain a solid, and washed three times with distilled water. The solid was recrystallized with a mixed solvent of pyridine and water (1.5:1) to obtain intermediate product ②, which was further dried under vacuum at 60 °C with a yield of 95%.

[0058] (3) Preparation of intermediate product ③ 30.81 g of intermediate product ② was added to 250 ml of phosphorus oxychloride, and stirred and refluxed at 110 °C for 12 h. After the reaction was completed, the excess phosphorus oxychloride was evaporated to dryness to obtain intermediate product ③, with a yield of 99%.

[0059] (4) Preparation of product MTNPPSi-1 36.61 g of intermediate product ③ and 10.12 g of triethylamine were added to 500 ml of dioxane and stirred until homogeneous. 5.16 g of diethylenetriamine was slowly added dropwise under ice bath conditions. After the addition was complete, stirring was continued at room temperature for 20 h. After the reaction was complete, the solid was filtered to obtain the product MTNPPSi-1, which was washed with distilled water and dried to obtain the product MTNPPSi-1, with a yield of 95%.

[0060] Example 4 (1) Preparation of intermediate product ① 12.61 g of melamine was added to 800 mL of dry pyridine and stirred thoroughly to dissolve. 26.86 g of diphenyl chlorophosphate was slowly added dropwise under an ice bath. After the addition was complete, the reaction was allowed to proceed at room temperature for 12 h. No further treatment was required after the reaction was completed.

[0061] (2) Preparation of intermediate product ② 29.49 g of triphenylchlorosilane was fully dissolved in 30 ml of pyridine and slowly added dropwise to the reaction system of intermediate product ① under ice bath. After the addition was complete, the reaction was carried out at room temperature for 12 h. The pyridine was removed by rotary evaporation, neutralized with 100 ml of saturated sodium bicarbonate solution, filtered to obtain a solid, and washed three times with distilled water. The solid was recrystallized with a mixed solvent of pyridine and water (1.5:1) to obtain intermediate product ②, which was further dried under vacuum at 60 °C with a yield of 94%.

[0062] (3) Preparation of intermediate product ③ 30.81 g of intermediate product ② was added to 300 ml of phosphorus oxychloride, and stirred and refluxed at 115 °C for 10 h. After the reaction was completed, the excess phosphorus oxychloride was evaporated to dryness to obtain intermediate product ③, with a yield of 99%.

[0063] (4) Preparation of product MTNPPSi-1 36.61 g of intermediate product ③ and 10.12 g of triethylamine were added to 500 ml of dioxane and stirred until homogeneous. 5.16 g of diethylenetriamine was slowly added dropwise under ice bath conditions. After the addition was complete, stirring was continued at room temperature for 18 h. After the reaction was complete, the solid was filtered off, washed with distilled water, and dried to obtain product MTNPPSi-1, with a yield of 95%.

[0064] Example 5 (1) Preparation of intermediate product ① 12.61 g of melamine was added to 800 mL of dry pyridine and stirred thoroughly to dissolve. 26.86 g of diphenyl chlorophosphate was slowly added dropwise under an ice bath. After the addition was complete, the reaction was allowed to proceed at room temperature for 12 h. No further treatment was required after the reaction was completed.

[0065] (2) Preparation of intermediate product ② 29.79 g of triphenylchlorosilane was fully dissolved in 30 ml of pyridine and slowly added dropwise to the reaction system of intermediate product ① under ice bath. After the addition was complete, the reaction was carried out at room temperature for 12 h. The pyridine was removed by rotary evaporation, neutralized with 100 ml of saturated sodium bicarbonate solution, filtered to obtain a solid, and washed three times with distilled water. The solid was recrystallized with a mixed solvent of pyridine and water (1.5:1) to obtain intermediate product ②, which was further dried under vacuum at 70 °C with a yield of 97%.

[0066] (3) Preparation of intermediate product ③ 30.81 g of intermediate product ② was added to 250 ml of phosphorus oxychloride, and stirred and refluxed at 110 °C for 12 h. After the reaction was completed, the excess phosphorus oxychloride was evaporated to dryness to obtain intermediate product ③, with a yield of 99%.

[0067] (4) Preparation of product MTNPPSi-1 36.61 g of intermediate product ③ and 10.12 g of triethylamine were added to 500 ml of dioxane and stirred until homogeneous. 5.16 g of diethylenetriamine was slowly added dropwise under ice bath conditions. After the addition was complete, stirring was continued at room temperature for 18 h. After the reaction was complete, the solid was filtered to obtain the product MTNPPSi-1, which was washed with distilled water and dried to give the product MTNPPSi-1, with a yield of 94%.

[0068] Example 6 (1) Preparation of intermediate product ① 12.61 g of melamine was added to 800 mL of dry pyridine and stirred thoroughly to dissolve. 26.86 g of diphenyl chlorophosphate was slowly added dropwise under an ice bath. After the addition was complete, the reaction was allowed to proceed at room temperature for 12 h. No further treatment was required after the reaction was completed.

[0069] (2) Preparation of intermediate product ② 29.49 g of triphenylchlorosilane was fully dissolved in 30 ml of pyridine and slowly added dropwise to the reaction system of intermediate product ① under ice bath. After the addition was complete, the reaction was carried out at room temperature for 12 h. The pyridine was removed by rotary evaporation, neutralized with 100 ml of saturated sodium bicarbonate solution, filtered to obtain a solid, and washed three times with distilled water. The solid was recrystallized with a mixed solvent of pyridine and water (1.5:1) to obtain intermediate product ②, which was further dried under vacuum at 70 °C with a yield of 94%.

[0070] (3) Preparation of intermediate product ③ 30.81 g of intermediate product ② was added to 250 ml of phosphorus oxychloride, and stirred and refluxed at 110 °C for 12 h. After the reaction was completed, the excess phosphorus oxychloride was evaporated to dryness to obtain intermediate product ③, with a yield of 99%.

[0071] (4) Preparation of product MTNPPSi-1 36.61 g of intermediate product ③ and 12.15 g of triethylamine were added to 500 ml of dioxane and stirred until homogeneous. 5.16 g of diethylenetriamine was slowly added dropwise under ice bath conditions. After the addition was complete, stirring was continued at room temperature for 18 h. After the reaction was complete, the solid was filtered to obtain the product MTNPPSi-1, which was washed with distilled water and dried to give the product MTNPPSi-1, with a yield of 95%.

[0072] Example 7 (1) Preparation of intermediate product ① 12.61 g of melamine was added to 800 mL of dry pyridine and stirred thoroughly to dissolve. 26.86 g of diphenyl chlorophosphate was slowly added dropwise under an ice bath. After the addition was complete, the reaction was allowed to proceed at room temperature for 12 h. No further treatment was required after the reaction was completed.

[0073] (2) Preparation of intermediate product ② 29.49 g of triphenylchlorosilane was fully dissolved in 30 ml of pyridine and slowly added dropwise to the reaction system of intermediate product ① under ice bath. After the addition was complete, the reaction was carried out at room temperature for 12 h. The pyridine was removed by rotary evaporation, neutralized with 100 ml of saturated sodium bicarbonate solution, filtered to obtain a solid, and washed three times with distilled water. The solid was recrystallized with a mixed solvent of pyridine and water (1.5:1) to obtain intermediate product ②, which was further dried under vacuum at 60 °C with a yield of 94%.

[0074] (3) Preparation of intermediate product ③ 30.81 g of intermediate product ② was added to 300 ml of phosphorus oxychloride, and stirred and refluxed at 110 °C for 12 h. After the reaction was completed, the excess phosphorus oxychloride was evaporated to dryness to obtain intermediate product ③, with a yield of 99%.

[0075] (4) Preparation of product MTNPPSi-1 36.61 g of intermediate product ③ and 10.12 g of triethylamine were added to 500 ml of tetrahydrofuran and stirred until homogeneous. 5.16 g of diethylenetriamine was slowly added dropwise under ice bath conditions. After the addition was complete, stirring was continued at room temperature for 18 h. After the reaction was complete, the solid was filtered to obtain the product MTNPPSi-1, which was washed with distilled water and dried to give the product MTNPPSi-1, with a yield of 96%.

[0076] Example 8 (1) Preparation of intermediate product ① 12.61 g of melamine was added to 800 mL of dry pyridine and stirred thoroughly to dissolve. 26.86 g of diphenyl chlorophosphate was slowly added dropwise under an ice bath. After the addition was complete, the reaction was allowed to proceed at room temperature for 12 h. No further treatment was required after the reaction was completed.

[0077] (2) Preparation of intermediate product ② 29.49 g of triphenylchlorosilane was fully dissolved in 30 ml of pyridine and slowly added dropwise to the reaction system of intermediate product ① under ice bath. After the addition was complete, the reaction was carried out at room temperature for 12 h. The pyridine was removed by rotary evaporation, neutralized with 100 ml of saturated sodium bicarbonate solution, filtered to obtain a solid, and washed three times with distilled water. The solid was recrystallized with a mixed solvent of pyridine and water (1.5:1) to obtain intermediate product ②, which was further dried under vacuum at 70 °C with a yield of 94%.

[0078] (3) Preparation of intermediate product ③ 30.81 g of intermediate product ② was added to 300 ml of phosphorus oxychloride, and stirred and refluxed at 110 °C for 12 h. After the reaction was completed, the excess phosphorus oxychloride was evaporated to dryness to obtain intermediate product ③, with a yield of 99%.

[0079] (4) Preparation of product MTNPPSi-1 36.61 g of intermediate product ③ and 10.12 g of triethylamine were added to 500 ml of acetone and stirred until homogeneous. 5.16 g of diethylenetriamine was slowly added dropwise under ice bath conditions. After the addition was complete, stirring was continued at room temperature for 18 h. After the reaction was complete, the solid was filtered to obtain the product MTNPPSi-1, which was washed with distilled water and dried to give the product MTNPPSi-1, with a yield of 95%.

[0080] Example 9 (1) Preparation of intermediate product ① 12.61 g of melamine was added to 800 mL of dry pyridine and stirred thoroughly to dissolve. 26.86 g of diphenyl chlorophosphate was slowly added dropwise under an ice bath. After the addition was complete, the reaction was allowed to proceed at room temperature for 12 h. No further treatment was required after the reaction was completed.

[0081] (2) Preparation of intermediate product ② 29.49 g of triphenylchlorosilane was fully dissolved in 30 ml of pyridine and slowly added dropwise to the reaction system of intermediate product ① under ice bath. After the addition was complete, the reaction was carried out at room temperature for 12 h. The pyridine was removed by rotary evaporation, neutralized with 100 ml of saturated sodium bicarbonate solution, filtered to obtain a solid, and washed three times with distilled water. The solid was recrystallized with a mixed solvent of pyridine and water (1.5:1) to obtain intermediate product ②, which was further dried under vacuum at 70 °C with a yield of 94%.

[0082] (3) Preparation of intermediate product ③ 30.81 g of intermediate product ② was added to 300 ml of phosphorus oxychloride, and stirred and refluxed at 110 °C for 12 h. After the reaction was completed, the excess phosphorus oxychloride was evaporated to dryness to obtain intermediate product ③, with a yield of 99%.

[0083] (4) Preparation of product MTNPPSi-1 36.61g of intermediate product ③ and 12.93g N,N Diisopropylethylamine was added to 500 mL of dioxane and stirred until homogeneous. 5.16 g of diethylenetriamine was then slowly added dropwise under ice bath conditions. After the addition was complete, stirring was continued at room temperature for 18 h. The reaction was completed by filtration to obtain a solid, which was washed with distilled water and dried to obtain product MTNPPSi-1, with a yield of 94%.

[0084] Example 10 (1) Preparation of intermediate product ① 12.61 g of melamine was added to 800 mL of dry pyridine and stirred thoroughly to dissolve. 26.86 g of diphenyl chlorophosphate was slowly added dropwise under an ice bath. After the addition was complete, the reaction was allowed to proceed at room temperature for 12 h. No further treatment was required after the reaction was completed.

[0085] (2) Preparation of intermediate product ② 29.49 g of triphenylchlorosilane was fully dissolved in 30 ml of pyridine and slowly added dropwise to the reaction system of intermediate product ① under ice bath. After the addition was complete, the reaction was carried out at room temperature for 12 h. The pyridine was removed by rotary evaporation, neutralized with 100 ml of saturated sodium bicarbonate solution, filtered to obtain a solid, and washed three times with distilled water. The solid was recrystallized with a mixed solvent of pyridine and water (1.5:1) to obtain intermediate product ②, which was further dried under vacuum at 70 °C with a yield of 94%.

[0086] (3) Preparation of intermediate product ③ 30.81 g of intermediate product ② was added to 250 ml of phosphorus oxychloride, and stirred and refluxed at 110 °C for 12 h. After the reaction was completed, the excess phosphorus oxychloride was evaporated to dryness to obtain intermediate product ③, with a yield of 99%.

[0087] (4) Preparation of product MTNPPSi-1 36.61g of intermediate product ③ and 15.52g N,N Diisopropylethylamine was added to 500 mL of dioxane and stirred until homogeneous. 5.16 g of diethylenetriamine was then slowly added dropwise under ice bath conditions. After the addition was complete, stirring was continued at room temperature for 18 h. The reaction was completed by filtration to obtain a solid, which was washed with distilled water and dried to obtain product MTNPPSi-1, with a yield of 94%.

[0088] Example 11 (1) Preparation of intermediate product ① 12.61 g of melamine was added to 800 mL of dry pyridine and stirred thoroughly to dissolve. 26.86 g of diphenyl chlorophosphate was slowly added dropwise under an ice bath. After the addition was complete, the reaction was allowed to proceed at room temperature for 16 h. No further treatment was required after the reaction was completed.

[0089] (2) Preparation of intermediate product ② 29.49 g of triphenylchlorosilane was fully dissolved in 30 ml of pyridine and slowly added dropwise to the reaction system of intermediate product ① under ice bath. After the addition was complete, the reaction was carried out at room temperature for 16 h. The pyridine was removed by rotary evaporation, neutralized with 100 ml of saturated sodium bicarbonate solution, filtered to obtain a solid, and washed three times with distilled water. The solid was recrystallized with a mixed solvent of pyridine and water (1.5:1) to obtain intermediate product ②, which was further dried under vacuum at 70 °C with a yield of 97%.

[0090] (3) Preparation of intermediate product ③ 30.81 g of intermediate product ② was added to 250 ml of phosphorus oxychloride, and stirred and refluxed at 115 °C for 10 h. After the reaction was completed, the excess phosphorus oxychloride was evaporated to dryness to obtain intermediate product ③, with a yield of 99%.

[0091] (4) Preparation of product MTNPPSi-1 36.61 g of intermediate product ③ and 12.15 g of triethylamine were added to 500 ml of dioxane and stirred until homogeneous. 5.16 g of diethylenetriamine was slowly added dropwise under ice bath conditions. After the addition was complete, stirring was continued at room temperature for 18 h. The solid was obtained by filtration after the reaction was complete. Washing with distilled water and drying yielded product MTNPPSi-1, with a yield of 97%.

[0092] Example 12 (1) Preparation of intermediate product ① 12.61 g of melamine was added to 800 mL of dry pyridine and stirred thoroughly to dissolve. 26.86 g of diphenyl chlorophosphate was slowly added dropwise under an ice bath. After the addition was complete, the reaction was allowed to proceed at room temperature for 16 h. No further treatment was required after the reaction was completed.

[0093] (2) Preparation of intermediate product ② 29.49 g of triphenylchlorosilane was fully dissolved in 30 ml of pyridine and slowly added dropwise to the reaction system of intermediate product ① under ice bath. After the addition was complete, the reaction was carried out at room temperature for 16 h. The pyridine was removed by rotary evaporation, neutralized with 100 ml of saturated sodium bicarbonate solution, filtered to obtain a solid, and washed three times with distilled water. The solid was recrystallized with a mixed solvent of pyridine and water (1.5:1) to obtain intermediate product ②, which was further dried under vacuum at 70 °C with a yield of 97%.

[0094] (3) Preparation of intermediate product ③ 30.81 g of intermediate product ② was added to 250 ml of phosphorus oxychloride, and stirred and refluxed at 115 °C for 10 h. After the reaction was completed, the excess phosphorus oxychloride was evaporated to dryness to obtain intermediate product ③, with a yield of 99%.

[0095] (4) Preparation of product MTNNPSi-2 36.61 g of intermediate product ③ and 12.15 g of triethylamine were added to 500 ml of dioxane and stirred until homogeneous. 7.32 g of triethylenetetramine was slowly added dropwise under ice bath conditions. After the addition was complete, stirring was continued at room temperature for 18 h. After the reaction was complete, the solid was filtered to obtain the product MTNPPSi-2, which was washed with distilled water and dried to give the product MTNPPSi-2, with a yield of 97%.

[0096] The chemical structural formula of MTNPPSi-2 is as follows: The product MTNPPSi-2 prepared in this embodiment was subjected to... 1¹H NMR (400 MHz, DMSO-d6) NMR spectroscopy analysis. The peak values ​​(δ) (ppm) are as follows: 10.58, 10.21, 7.52-7.49, 7.39-7.36, 7.33-7.28, 7.26-7.22, 5.49, 4.71, 4.07, 3.38, 2.80, 2.78, 2.76, 2.74. This is consistent with the chemical environment of H in the product MTNPPSi-2.

[0097] Example 13 (1) Preparation of intermediate product ① 12.61 g of melamine was added to 800 mL of dry pyridine and stirred thoroughly to dissolve. 26.86 g of diphenyl chlorophosphate was slowly added dropwise under an ice bath. After the addition was complete, the reaction was allowed to proceed at room temperature for 16 h. No further treatment was required after the reaction was completed.

[0098] (2) Preparation of intermediate product ② 29.49 g of triphenylchlorosilane was fully dissolved in 30 ml of pyridine and slowly added dropwise to the reaction system of intermediate product ① under ice bath. After the addition was complete, the reaction was carried out at room temperature for 16 h. The pyridine was removed by rotary evaporation, neutralized with 100 ml of saturated sodium bicarbonate solution, filtered to obtain a solid, and washed three times with distilled water. The solid was recrystallized with a mixed solvent of pyridine and water (1.5:1) to obtain intermediate product ②, which was further dried under vacuum at 70 °C with a yield of 97%.

[0099] (3) Preparation of intermediate product ③ 30.81 g of intermediate product ② was added to 250 ml of phosphorus oxychloride, and stirred and refluxed at 115 °C for 10 h. After the reaction was completed, the excess phosphorus oxychloride was evaporated to dryness to obtain intermediate product ③, with a yield of 99%.

[0100] (4) Preparation of product MTNNPSi-3 36.61 g of intermediate product ③ and 12.15 g of triethylamine were added to 500 ml of dioxane and stirred until homogeneous. 9.47 g of tetraethylenepentamine was slowly added dropwise under ice bath conditions. After the addition was complete, stirring was continued at room temperature for 18 h. After the reaction was complete, the solid was filtered to obtain the product MTNPPSi-3, which was washed with distilled water and dried to give the product MTNPPSi-3, with a yield of 97%.

[0101] The chemical structural formula of MTNPPSi-3 is as follows: The product MTNPPSi-3 prepared in this embodiment was subjected to... 1¹H NMR (400 MHz, DMSO-d6) NMR spectroscopy analysis. The peak values ​​(ppm) are as follows: 10.58, 10.21, 7.52-7.49, 7.39-7.36, 7.33-7.28, 7.26-7.22, 5.49, 4.71, 4.07, 3.40, 3.38, 2.80, 2.78, 2.76, 2.74. This is consistent with the chemical environment of H in the product MTNPSi-3.

[0102] Example 14 (1) Preparation of intermediate product ① 12.61 g of melamine was added to 800 mL of dry pyridine and stirred thoroughly to dissolve. 26.86 g of diphenyl chlorophosphate was slowly added dropwise under an ice bath. After the addition was complete, the reaction was allowed to proceed at room temperature for 16 h. No further treatment was required after the reaction was completed.

[0103] (2) Preparation of intermediate product ② 29.49 g of triphenylchlorosilane was fully dissolved in 30 ml of pyridine and slowly added dropwise to the reaction system of intermediate product ① under ice bath. After the addition was complete, the reaction was carried out at room temperature for 16 h. The pyridine was removed by rotary evaporation, neutralized with 100 ml of saturated sodium bicarbonate solution, filtered to obtain a solid, and washed three times with distilled water. The solid was recrystallized with a mixed solvent of pyridine and water (1.5:1) to obtain intermediate product ②, which was further dried under vacuum at 70 °C with a yield of 97%.

[0104] (3) Preparation of intermediate product ③ 30.81 g of intermediate product ② was added to 250 ml of phosphorus oxychloride, and stirred and refluxed at 115 °C for 10 h. After the reaction was completed, the excess phosphorus oxychloride was evaporated to dryness to obtain intermediate product ③, with a yield of 99%.

[0105] (4) Preparation of product MTNPPSi-4 36.61 g of intermediate product ③ and 12.15 g of triethylamine were added to 500 ml of dioxane and stirred until homogeneous. 3.01 g of ethylenediamine was slowly added dropwise under ice bath conditions. After the addition was complete, stirring was continued at room temperature for 18 h. After the reaction was complete, the solid was filtered off, washed with distilled water, and dried to obtain product MTNPPSi-4, with a yield of 97%.

[0106] The chemical structural formula of MTNPPSi-4 is as follows: The product MTNPPSi-4 prepared in this embodiment was subjected to... 1¹H NMR (400 MHz, DMSO-d6) NMR spectroscopy analysis. The peak values ​​(ppm) are as follows: 10.58, 10.21, 7.52-7.49, 7.39-7.36, 7.33-7.28, 7.26-7.22, 5.49, 5.01, 2.98, 2.89, which is consistent with the chemical environment of H in the product MTNPSi-4.

[0107] Example 15 (1) Preparation of intermediate product ④ 12.61 g of melamine was added to 800 mL of dry pyridine and stirred thoroughly to dissolve. 58.98 g of triphenylchlorosilane (dissolved in 30 mL of pyridine) was slowly added dropwise under an ice bath. After the addition was complete, the mixture was reacted at room temperature for 16 h. The pyridine was removed by rotary evaporation and neutralized with 100 mL of saturated sodium bicarbonate solution. The solid was obtained by filtration and washed three times with distilled water. The intermediate product ④ was recrystallized with a mixed solvent of pyridine and water (1.5:1) and further dried under vacuum at 70 °C. The yield was 97%.

[0108] The chemical structural formula of intermediate product ④ is as follows: The intermediate product ④ prepared in this embodiment is subjected to... 1 ¹H NMR (400 MHz, DMSO-d6) NMR spectroscopy analysis. The peak values ​​δ (ppm) are as follows: 7.52-7.49, 7.34-7.28, 6.5, 5.68, which are consistent with the chemical environment of H in intermediate ①.

[0109] (2) Preparation of intermediate product ⑤ 30.81 g of intermediate product ⑤ was added to 250 ml of phosphorus oxychloride, and stirred and refluxed at 115 °C for 10 h. After the reaction was completed, the excess phosphorus oxychloride was evaporated to dryness to obtain intermediate product ⑤ with a yield of 99%.

[0110] The chemical structural formula of intermediate product ⑤ is as follows: The intermediate product ⑤ prepared in this embodiment is subjected to... 1 ¹H NMR (400 MHz, DMSO-d6) NMR spectroscopy analysis. The peak values ​​δ (ppm) are as follows: 9.45, 7.52-7.49, 7.34-7.28, 5.89, which are consistent with the chemical environment of H in intermediate ②.

[0111] (3) Preparation of product TNPPSi-1 36.61 g of intermediate product ⑤ and 12.15 g of triethylamine were added to 500 ml of dioxane and stirred until homogeneous. 5.16 g of diethylenetriamine was slowly added dropwise under ice bath conditions. After the addition was complete, stirring was continued at room temperature for 18 h. After the reaction was complete, the solid was filtered to obtain the product TNPPSi-1, which was washed with distilled water and dried to obtain the product TNPPSi-1 in 97% yield.

[0112] The chemical structural formula of TNPPSi-1 is as follows: The TNPPSi-1 prepared in this embodiment was subjected to... 1 ¹H NMR (400 MHz, DMSO-d6) NMR spectroscopy analysis. The peak values ​​δ (ppm) are as follows: 9.86, 7.52-7.48, 7.35-7.28, 5.89, 4.71, 3.28, 2.8, 2.78, 2.71, which is consistent with the chemical environment of H in TNPPSi-1.

[0113] Example 16 (1) Preparation of intermediate product ④ 12.61 g of melamine was added to 800 mL of dry pyridine and stirred thoroughly to dissolve. 58.98 g of triphenylchlorosilane (dissolved in 30 mL of pyridine) was slowly added dropwise under an ice bath. After the addition was complete, the mixture was reacted at room temperature for 16 h. The pyridine was removed by rotary evaporation and neutralized with 100 mL of saturated sodium bicarbonate solution. The solid was obtained by filtration and washed three times with distilled water. The intermediate product ④ was recrystallized with a mixed solvent of pyridine and water (1.5:1) and further dried under vacuum at 70 °C. The yield was 97%.

[0114] (2) Preparation of intermediate product ⑤ 30.81 g of intermediate product ④ was added to 250 ml of phosphorus oxychloride, and stirred and refluxed at 115 °C for 10 h. After the reaction was completed, the excess phosphorus oxychloride was evaporated to dryness to obtain intermediate product ⑤, with a yield of 99%.

[0115] (3) Preparation of product TNPPSi-2 36.61 g of intermediate product ⑤ and 12.15 g of triethylamine were added to 500 ml of dioxane and stirred until homogeneous. 7.32 g of triethylenetetramine was slowly added dropwise under ice bath conditions. After the addition was complete, stirring was continued at room temperature for 18 h. The solid was obtained by filtration after the reaction was complete. Washing with distilled water and drying yielded product TNPPSi-2, with a yield of 95%.

[0116] The chemical structural formula of TNPPSi-2 is as follows: The TNPPSi-2 prepared in this embodiment was subjected to... 1¹H NMR (400 MHz, DMSO-d6) NMR spectroscopy analysis. The peak values ​​δ (ppm) are as follows: 9.86, 7.52-7.49, 7.34-7.28, 5.89, 4.71, 4.07, 3.37, 2.8, 2.78, 2.76, 2.74, which is consistent with the chemical environment of H in TNPPSi-2.

[0117] Example 17 (1) Preparation of intermediate product ④ 12.61 g of melamine was added to 800 mL of dry pyridine and stirred thoroughly to dissolve. 58.98 g of triphenylchlorosilane (dissolved in 30 mL of pyridine) was slowly added dropwise under an ice bath. After the addition was complete, the mixture was reacted at room temperature for 16 h. The pyridine was removed by rotary evaporation and neutralized with 100 mL of saturated sodium bicarbonate solution. The solid was obtained by filtration and washed three times with distilled water. The intermediate product ④ was recrystallized with a mixed solvent of pyridine and water (1.5:1) and further dried under vacuum at 70 °C. The yield was 97%.

[0118] (2) Preparation of intermediate product ⑤ 30.81 g of intermediate product ④ was added to 250 ml of phosphorus oxychloride, and stirred and refluxed at 115 °C for 10 h. After the reaction was completed, the excess phosphorus oxychloride was evaporated to dryness to obtain intermediate product ⑤, with a yield of 99%.

[0119] (3) Preparation of product TNPPSi-3 36.61 g of intermediate product ⑤ and 12.15 g of triethylamine were added to 500 ml of dioxane and stirred until homogeneous. 9.47 g of tetraethylenepentamine was slowly added dropwise under ice bath conditions. After the addition was complete, stirring was continued at room temperature for 18 h. The solid was obtained by filtration after the reaction was complete. Washing with distilled water and drying yielded product TNPPSi-3, with a yield of 98%.

[0120] The chemical structural formula of TNPPSi-3 is as follows: The TNPPSi-3 prepared in this embodiment was subjected to... 1 ¹H NMR (400 MHz, DMSO-d6) NMR spectroscopy analysis. The peak values ​​(ppm) are as follows: 9.86, 7.52-7.49, 7.33-7.28, 5.89, 4.71, 4.07, 3.40, 3.37, 2.8, 2.78, 2.76, 2.74, which is consistent with the chemical environment of H in TNPPSi-3.

[0121] Examples 18-21 1) Weigh the E51 epoxy resin, diaminodiphenylmethane (DDM) curing agent and MTNPPSi flame retardant according to the formula in Table 1; 2) Heat E51 at 110℃ and add MTNPPSi flame retardant, stir evenly, remove air bubbles by vacuuming, and obtain primary mixture; 3) Add DDM curing agent to the primary mixture, stir evenly at 110℃, remove air bubbles by vacuuming, and obtain the secondary mixture; 4) Transfer the secondary mixture to a preheated mold, place it in an oven, cure at 80°C for 2 hours, then raise the temperature to 150°C for 6 hours. After curing, allow it to cool naturally to room temperature to obtain the MTNPPSi flame-retardant modified epoxy resin material.

[0122] Examples 22-24 1) As shown in Table 1, weigh E51 epoxy resin, diaminodiphenylmethane (DDM) curing agent and TNPPSi flame retardant; 2) Heat E51 at 110℃ and add TNPPSi flame retardant, stir evenly, remove air bubbles by vacuuming, and obtain primary mixture; 3) Add DDM curing agent to the primary mixture, stir evenly at 110℃, remove air bubbles by vacuuming, and obtain the secondary mixture; 4) Transfer the secondary mixture to a preheated mold, place it in an oven, cure at 80°C for 2 hours, then raise the temperature to 150°C for 6 hours. After curing, allow it to cool naturally to room temperature to obtain TNPPSi flame-retardant modified epoxy resin material.

[0123] A blank control group was set up. The difference from the example is that no flame retardant was added in this application example. Otherwise, it is the same as the application example and will not be repeated here.

[0124] Table 1 Formulation of Flame-Retardant Modified Epoxy Resin Materials The flame-retardant-modified epoxy resins obtained in Examples 18-24 and the unmodified epoxy resins from the control group were subjected to LOI tests, UL-94 vertical burning tests, and cone calorimetry tests. The results are shown in Table 2. The LOI test was conducted according to ASTM D2863-19 standard, with sample dimensions of 130 × 6.5 × 3 mm. 2 The UL-94 vertical burning test was conducted according to GB / T2408-2008 standard, with sample dimensions of 130×13×3mm. 2 The cone calorimeter (CCT) sample size is 100 mm × 100 mm × 3 mm. The test is conducted according to ISO 5660, with the sample wrapped in aluminum foil and horizontally exposed to 35 kW / m². 2 Under the heat flux.

[0125] As shown in Table 2, the LOI value of the control group without flame retardant was 23.5%, failing the UL-94 test. Adding MTNPPSi or TNPPSi flame retardants significantly enhanced the flame retardant properties of epoxy resin materials and reduced the heat of combustion. Compared to the control group, the LOI values ​​of Examples 18, 19, 20, and 21 were 35.5%, 35.2%, 35.3%, and 34.7%, respectively, representing increases of 51.1%, 49.8%, 50.2%, and 47.7%, and all passed the UL-94 V-0 rating. The PHRR decreased by 66.3%, 64.9%, 67.3%, and 65.7%, respectively, and the THR decreased by 55.9%, 54.4%, 56.9%, and 53.7%, respectively. The LOI values ​​of Examples 22, 23, and 24 were 29.8%, 30.1%, and 30.7%, respectively, representing increases of 26.8%, 28.1%, and 30.6%, and also passed the UL-94 test. With a V-1 rating, the PHRR decreased by 58.9%, 57.3%, and 59.1%, respectively, and the THR decreased by 42.7%, 44.2%, and 43.4%, respectively. This is attributed to the unique flame-retardant mechanism of the phosphorus, silicon, and triazine structures contained in the flame retardant, which can enhance the flame-retardant properties of epoxy resin materials.

[0126] Furthermore, the above results show that for flame-retardant modified epoxy resin materials, MTNPPSi exhibits superior flame-retardant properties and lower heat release during combustion compared to TNPPSi. This is attributed to the multiple flame-retardant mechanisms of MTNPPSi, which combines both high-valence and low-valence phosphorus. On one hand, high-valence phosphorus decomposes at high temperatures to generate acids, catalyzing the formation of char from the epoxy resin and inhibiting the thermal decomposition of the material. On the other hand, low-valence phosphorus generates flame retardants at high temperatures that can quench and promote the combustion chain reaction, inhibiting the combustion reaction and reducing the heat released during combustion. Moreover, there is no significant difference in flame-retardant performance between MTNPPSi and TNPPSi flame retardants with different structures, indicating that the flame-retardant properties of the flame retardants are mainly determined by the functional units containing phosphorus and silicon elements.

[0127] Table 2. Test results of flame retardant and combustion performance of flame-retardant modified epoxy resin materials. Mechanical properties were tested on the flame-retardant-modified epoxy resins obtained in Examples 18-24 and the control group. The test results are as follows: Figure 1 , Figure 2 and Figure 3 As shown.

[0128] The results showed that, compared with the control group, the flame retardant-modified epoxy resin material exhibited significant improvements in impact strength, tensile strength, and flexural strength. This indicates that flame retardants with flexible organic polyamine molecular chain structures can enhance the mechanical properties of materials. Furthermore, for MTNPPSi or TNPPSi flame retardants with different structures, the impact strength, tensile strength, and flexural strength all increased with the increase of the flexible organic polyamine chain length within the molecular structure, demonstrating that increasing the molecular chain length can enhance the mechanical properties of epoxy resin materials.

Claims

1. A triazine-based phosphorus- and silicon-containing reactive intumescent flame retardant, characterized in that, The reactive intumescent flame retardant includes polyphosphorus oxidized forms and monophosphorus oxidized forms, and its structural formula is as follows: 1) When the structure is in the polyphosphorus oxidation state: 2) When the structure is in the single phosphorus oxidation state: Where p is an integer ≥ 0; R is phenyl, methyl, ethyl, or propyl; R1 is phenyl, methyl, ethyl, or propyl; R2 is either -NH- or -CH2-.

2. A method for preparing a triazine-based phosphorus- and silicon-containing reactive intumescent flame retardant as described in claim 1, characterized in that, Includes the following steps: 1) When the flame retardant structure is in the polyphosphorus oxidation state: (1) Melamine was added to pyridine, mixed well, phosphoric acid chloride reagent was added, mixed well, and then the temperature was raised to react, and the reaction system of intermediate product ① was obtained. (2) Dissolve the chlorosilane reagent in pyridine, mix well, and add it to the reaction system of intermediate product ①. Heat the mixture to carry out the reaction and obtain intermediate product ②. (3) Dissolve intermediate product ② in a certain amount of phosphorus oxychloride according to the proportion, and react at 100~120℃ for a set time to obtain intermediate product ③; (4) Add intermediate product ③ and organic base to the first solvent in proportion, mix well, add organic polyamine to it at -3~3℃, heat to 20~40℃, and set reaction time to obtain triazine-based reactive intumescent flame retardant MTNPPSi containing polyphosphorus oxidation state and silicon. 2) When the flame retardant structure is in the monophosphorus oxidized state: (a) Melamine was added to pyridine, mixed well, and a chlorosilane reagent was slowly added dropwise at -3~3℃. The temperature was raised to 20~40℃, and the reaction was carried out for a set time to obtain intermediate product ④. (b) Dissolve intermediate product ④ in a certain amount of phosphorus oxychloride in proportion, react at 100~120℃ for a set time to obtain intermediate product ⑤; (c) Add intermediate product ⑤ and organic base to the first solvent in proportion, mix well, add organic polyamine to it at -3~3℃, and heat to react to obtain triazine-based reactive intumescent flame retardant TNPPSi containing monophosphorus oxidation state and silicon.

3. The preparation method according to claim 2, characterized in that, In step (1), a phosphoric acid chloride reagent is added at -3 to 3°C; the phosphoric acid chloride reagent is any one of diphenyl chlorophosphate, dimethyl chlorophosphate, diethyl chlorophosphate, etc., or a mixture thereof; in step (1), the molar ratio of melamine to phosphoric acid chloride reagent is 1:0.5-1.5; in step (a), the molar ratio of melamine to chlorosilane reagent is 1:1-3; preferably, the molar ratio is 1:1.5; 1:2; 1:3; most preferably, the molar ratio of melamine to chlorosilane reagent is 1:2; in step (1) or step (a), the mass ratio of melamine to pyridine is 1:30-60; the reaction is carried out at 20 to 40°C for 12 to 18 hours.

4. The preparation method according to claim 2 or 3, characterized in that, In step (1), the chemical structural formula of the intermediate product ① is: ； In step (a), the chemical structural formula of the intermediate product ④ is: ； Wherein, R is phenyl, methyl, ethyl or propyl; R1 is phenyl, methyl, ethyl or propyl.

5. The preparation method according to claim 2, characterized in that, In step (2) or step (a), the chlorinated silane reagent is any one of tert-butyldimethylchlorosilane, tert-butyldiphenylchlorosilane, triisopropylchlorosilane, triphenylchlorosilane, or a mixture thereof; in step (2), the chlorinated silane reagent is added to the reaction system of intermediate product ① at -3 to 3°C; the molar ratio of intermediate product ① to chlorinated silane reagent is 1:0.5-1.5; the reaction is carried out at 20 to 40°C for 8 to 16 hours.

6. The preparation method according to claim 2 or 5, characterized in that, In step (2), the chemical structural formula of the intermediate product ② is: ； In step (b), the chemical structural formula of the intermediate product ⑤ is: ； Wherein, R is phenyl, methyl, ethyl or propyl; R1 is phenyl, methyl, ethyl or propyl.

7. The preparation method according to claim 2, characterized in that, In step (3) or step (b), the molar ratio of intermediate product ② or intermediate product ④ to phosphorus oxychloride is 1:20-50; the reaction is carried out at 100~120℃ for 8-16 hours; the intermediate product ③ in step (3) has the following chemical structural formula: ； Wherein, R is phenyl, methyl, ethyl or propyl; R1 is phenyl, methyl, ethyl or propyl.

8. The preparation method according to claim 2, characterized in that, In step (4) or step (c), the first solvent is selected from dioxane, tetrahydrofuran, acetonitrile, ethyl acetate, acetone, or toluene; the organic polyamine is any one or a mixture of pentaethylenehexamine, tetraethylenepentamine, triethylenetetramine, diethylenetriamine, ethylenediamine, 1,4-diaminobutane, 1,6-hexanediamine, 1,7-heptanediamine, or ethylenediamine, butanediamine, 6-hexanediamine, 7-heptanediamine, and 10-decanediamine; the organic base is triethylamine, N,N - Any one or a mixture thereof, such as diisopropylethylamine, pyridine, etc.; in step (4), the molar ratio of intermediate product ③ to organic base is 1:2-4; the molar ratio of intermediate product ③ to organic polyamine is 1:1; organic polyamine is added at a temperature of -3~3℃; in step (c), the molar ratio of intermediate product ⑤ to organic base is 1:2-4; the molar ratio of intermediate product ⑤ to organic polyamine is 1:

1. All reactions are carried out at 20~40℃ for 12-18h.

9. The application of a reactive intumescent flame retardant as described in claim 1 in modified epoxy resin.

10. A flame-retardant modified epoxy resin, characterized in that, It includes an epoxy resin matrix and a reactive intumescent flame retardant prepared by the preparation method described in claim 1 or claims 2-8.

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