阅读说明：本技术 一种含磷氮硅的二氧化钛杂化纳米粒子阻燃剂及其制备方法和应用 (Titanium dioxide hybrid nano particle flame retardant containing phosphorus, nitrogen and silicon and preparation method and application thereof ) 是由 戴李宗 纪荣彬 卢伟 彭超华 曾珊妮 李伟航 许一婷 于 2020-11-11 设计创作，主要内容包括：本发明公开了一种含磷氮硅的二氧化钛杂化纳米粒子阻燃剂及其制备方法和应用。其制备方法包括如下步骤：(1)香草醛、三乙胺和三氯氧磷在第一溶剂中反应得到产物VP3；(2)二氯二苯基硅烷、K-2CO-3和对硝基苯酚在第二溶剂中反应得到产物DPNSi；DPNSi溶于第三溶剂后加入钯碳超,与水合肼的乙醇溶液还原反应得到DPASi；(3)将分散有二氧化钛纳米颗粒的乙酸乙酯溶液加入VP3和DPASi,缩合聚合反应,即得含磷氮硅的二氧化钛杂化纳米粒子阻燃剂VPASi。(The invention discloses a titanium dioxide hybrid nano particle flame retardant containing phosphorus, nitrogen and silicon, and a preparation method and application thereof. The preparation method comprises the following steps: (1) reacting vanillin, triethylamine and phosphorus oxychloride in a first solvent to obtain a product VP 3; (2) dichlorodiphenylsilane, K 2 CO 3 Reacting with p-nitrophenol in a second solvent to obtain a product DPNSi; dissolving DPNSi in the third solvent, adding Pd/C, and dissolving with hydrazine hydrate ethanolPerforming liquid reduction reaction to obtain DPASi; (3) and adding the ethyl acetate solution dispersed with the titanium dioxide nano particles into VP3 and DPASi, and carrying out condensation polymerization reaction to obtain the phosphorus-nitrogen-silicon-containing titanium dioxide hybrid nano particle flame retardant VPASi.)

1. A preparation method of a titanium dioxide hybrid nano particle flame retardant containing phosphorus, nitrogen and silicon is characterized by comprising the following steps: the method comprises the following steps:

1) reacting vanillin, triethylamine and phosphorus oxychloride in a first solvent to obtain a product VP3 shown in a formula I;

2) dichlorodiphenylsilane, K₂CO₃And p-nitrophenol in a second solvent, refluxing, condensing and heatingReacting for 24-48 h at the temperature of 30-45 ℃, and carrying out solid-liquid separation on the reaction liquid to obtain a solid part which is a product DPNSi shown in a formula II; dissolving DPNSi in a third solvent, adding palladium carbon, dispersing uniformly, introducing nitrogen, refluxing and condensing a reaction system, heating to 70-80 ℃, dripping an ethanol solution of hydrazine hydrate, and reacting for 24-48 h; cooling to room temperature, removing palladium carbon, adding water, stirring, and performing solid-liquid separation to obtain a solid part which is a product DPASi shown in a formula III;

3) and dissolving the VP3 in an ethyl acetate solution in which titanium dioxide nano particles are dispersed, adding an ethyl acetate solution containing the DPASi, and reacting at room temperature for 0.5-1 h to obtain the phosphorus-nitrogen-silicon-containing titanium dioxide hybrid nano particle flame retardant VPASi.

2. The method of claim 1, wherein: the diameter of the titanium dioxide nanoparticles is 50-100 nm.

3. The method of claim 1, wherein: in the step 1), vanillin, triethylamine and phosphorus oxychloride are stirred in a first solvent for 1-3 h, and then the temperature is raised to 40-60 ℃ for reaction for 3-9 h; after cooling to room temperature, petroleum ether was poured in to give a precipitate as the product VP 3.

4. The method of claim 1, wherein: in the step 1), the formula proportion of vanillin, phosphorus oxychloride and triethylamine is 2.6-2.8 g: 0.9-1.0 g: 2-5 mL.

5. The method of claim 1, wherein: in the step 2), the formula proportion of dichlorodiphenylsilane, p-nitrophenol and potassium carbonate is 2-2.2 g: 2.18-2.32 g: 2.18-2.32 g.

6. The method of claim 1, wherein: in the step 2), the formula ratio of the DPNSi, the hydrazine hydrate ethanol solution and the palladium carbon is 1-1.1 g: 10-20 mL: 400-600 mg.

7. The method of claim 1, wherein: in the step 3), the formula proportion of the VP3, the DPASi and the titanium dioxide nanoparticles is 1-1.8 g: 1-2.5 g: 0.4 to 0.6 g.

8. The method of claim 1, wherein: the first solvent comprises at least one of chloroform, ethyl acetate, or acetonitrile; the second solvent comprises at least one of methanol, diethyl ether or acetone; the third solvent includes at least one of methanol, ethanol, or dichloromethane.

9. A silicon nitrogen containing titanium dioxide hybrid nanoparticle flame retardant prepared according to the preparation method of any one of claims 1 to 8.

10. The application of the titanium dioxide hybrid nanoparticle flame retardant containing phosphorus, nitrogen and silicon as claimed in claim 9 in preparing flame retardant materials.

Technical Field

The invention belongs to the technical field of flame-retardant materials, and particularly relates to a flame retardant.

Background

As a material with wide application prospect, the polymer material has the advantages of good physical and chemical stability, easy modification, easy processing, good optical performance and the like, and is applied to the fields of automobile manufacturing, electronic devices, coatings, buildings and the like. However, the polymer material is easily subjected to stress relaxation and creep phenomena in terms of strength, has certain limitations in terms of high-temperature performance, is poor in fire resistance, and is very flammable.

There is a great need for polymeric materials that have improved fire retardant properties without degrading their mechanical properties. However, the conventional titanium dioxide flame-retardant system for polymers still has problems of poor dispersibility, low flame-retardant efficiency, and the like. Therefore, there is a need for improvement thereof.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a titanium dioxide hybrid nano particle flame retardant containing phosphorus, nitrogen and silicon and a preparation method thereof. The titanium dioxide hybrid nano particle flame retardant containing phosphorus, nitrogen and silicon can be applied to modification of high polymer materials to prepare a multi-element synergistic flame retardant material with high flame retardant performance and high mechanical performance.

One of the technical schemes adopted by the invention for solving the technical problems is as follows:

a preparation method of a titanium dioxide hybrid nano particle flame retardant containing silicon nitrogen comprises the following steps:

1) reacting vanillin, triethylamine and phosphorus oxychloride in a first solvent to obtain a product VP 3; VP3 has a structural formula shown in formula I:

2) dichlorodiphenylsilane, K₂CO₃And p-nitrophenol in a second solvent, refluxing, condensing and heating to 30-45 ℃, reacting for 24-48 h, and carrying out solid-liquid separation on the reaction liquid to obtain a solid part which is a product DPNSi; dissolving DPNSi in a third solvent, adding palladium carbon, dispersing uniformly, introducing nitrogen, refluxing and condensing a reaction system, heating to 70-80 ℃, dripping an ethanol solution of hydrazine hydrate, and reacting for 24-48 h; cooling to room temperature, removing palladium carbon, adding water, stirring for 1-6 h, and carrying out solid-liquid separation to obtain a solid part which is a product DPASi;

the structural formula of DPNSi is shown as a formula II:

the structural formula of the DPASi is shown as a formula III:

3) and dissolving VP3 in the ethyl acetate solution in which the titanium dioxide nanoparticles are dispersed, adding the ethyl acetate solution containing DPASi, and reacting at room temperature for 0.5-1 h to obtain the phosphorus-nitrogen-silicon-containing titanium dioxide hybrid nanoparticle flame retardant VPASi.

In a preferred embodiment of the present invention, the diameter of the titanium dioxide nanoparticles is 50 to 100 nm.

In a preferred embodiment of the invention, in the step 1), vanillin, triethylamine and phosphorus oxychloride are stirred in a first solvent for 1 to 3 hours, and then the temperature is raised to 40 to 60 ℃ for reaction for 3 to 9 hours; after cooling to room temperature, petroleum ether was poured in to give a precipitate as the product VP 3.

In a preferred embodiment of the present invention, in the step 1), the formula ratio of vanillin, phosphorus oxychloride and triethylamine is 2.6-2.8 g: 0.9-1.0 g: 2-5 mL. Further, the formula proportion of the vanillin, the first solvent, the phosphorus oxychloride and the triethylamine is 2.6-2.8 g: 50-100 mL: 0.9-1.0 g: 2-5 mL.

In a preferred embodiment of the invention, in the step 2), the formulation ratio of dichlorodiphenylsilane, p-nitrophenol and potassium carbonate is 2-2.2 g: 2.18-2.32 g: 2.18-2.32 g. Further, the formula proportion of the dichlorodiphenylsilane, the p-nitrophenol, the potassium carbonate and the second solvent is 2-2.2 g: 2.18-2.32 g: 2.18-2.32 g: 50-100 mL.

In a preferred embodiment of the invention, in the step 2), the formulation ratio of the DPNSi, the hydrazine hydrate ethanol solution and the palladium carbon is 1-1.1 g: 10-20 mL: 400-600 mg. Further, the formula proportion of the DPNSi, the hydrazine hydrate ethanol solution, the palladium carbon and the third solvent is 1-1.1 g: 10-20 mL: 400-600 mg: 80-100 mL.

Further, in the ethanol solution of hydrazine hydrate, the concentration of hydrazine hydrate is 75-85 wt%.

In a preferred embodiment of the invention, in the step 3), the formula ratio of the VP3, the DPASi and the titanium dioxide nanoparticles is 1-1.8 g: 1-2.5 g: 0.4 to 0.6 g. Further, the formula ratio of the VP3, the DPASi, the ethyl acetate and the titanium dioxide nanoparticles is 1-1.8 g: 1-2.5 g: 20-70 mL: 0.4 to 0.6 g.

Further, the first solvent includes at least one of chloroform, ethyl acetate, or acetonitrile.

Further, the second solvent includes at least one of methanol, diethyl ether, or acetone.

Further, the third solvent includes at least one of methanol, ethanol, or dichloromethane.

The second technical scheme adopted by the invention for solving the technical problems is as follows:

the titanium dioxide hybrid nano particle flame retardant containing phosphorus, nitrogen and silicon prepared by the preparation method.

The phosphorus-nitrogen-silicon-containing titanium dioxide hybrid nano particle flame retardant is prepared by coating a phosphorus-nitrogen-silicon-containing Schiff base polymer on titanium dioxide nano particles, wherein the phosphorus-nitrogen-silicon-containing Schiff base polymer is prepared by polymerizing VP3 and DPASi.

In the titanium dioxide hybrid nano particle flame retardant containing phosphorus, nitrogen and silicon, vanillin endows the flame retardant with better compatibility with a matrix, and can endow organic polymers with better water resistance, chemical corrosion resistance and high and low temperature resistance, or improve mechanical properties, flame retardant property and the like. Phosphorus oxychloride, as a commonly used phosphorus-containing organic monomer, is one of the raw materials of the flame retardant. The flexible dichlorodiphenylsilane can increase the toughness of the material, and the impact strength of the material can be increased by the active imine bond synthesized by the aldehyde-amine reaction. The titanium dioxide nano-particles are used as a metal oxide flame retardant, so that the mechanical property of the polymer material is improved, and the titanium dioxide nano-particles can be used for cooperating with other flame-retardant elements to play roles in resisting dripping, suppressing smoke and promoting carbon formation, thereby achieving the flame-retardant effect.

The third technical scheme adopted by the invention for solving the technical problems is as follows:

application of a titanium dioxide hybrid nano particle flame retardant containing phosphorus, nitrogen and silicon in preparing a flame retardant material.

The invention also aims to apply the titanium dioxide hybrid nano particles containing phosphorus, nitrogen and silicon to flame retardant modification of high polymer materials such as epoxy resin, polyurethane, polyethylene, polypropylene, polycarbonate and the like.

Specifically, VPASi is blended with a high polymer material in different proportions to prepare the flame-retardant modified high polymer material. The polymer comprises epoxy resin, polyurethane, polyethylene, polypropylene, polycarbonate and the like.

The equipment, reagents, processes, parameters and the like related to the invention are conventional equipment, reagents, processes, parameters and the like except for special description, and no embodiment is needed.

All ranges recited herein include all point values within the range.

In the invention, the room temperature, namely the normal environment temperature, can be 10-30 ℃.

The invention has the beneficial effects that:

1. the flame retardant synthesized by the method has the advantages of low raw material price, easy synthesis and preparation, and green and environment-friendly raw material vanillin which is an important renewable resource.

2. In the Schiff base polymer as the shell layer, the organic phosphine nitrogen system can fully play roles of capturing free radicals, inhibiting combustion, promoting carbon formation and diluting gas during combustion. Meanwhile, the titanium dioxide nano-particles as the core are non-toxic and have good chemical stability, the mechanical property of the matrix is increased due to good dispersion property, the titanium dioxide nano-particles play a role of a carbon layer skeleton in the combustion process of a polymer, and the titanium dioxide nano-particles, phosphoric acid generated from a phosphorus component and polyphosphoric acid, generate porous titanium pyrophosphate TiP₂PO₇And the high-quality carbon layer is formed by the synergistic effect of phenyl siloxane, so that the high-temperature carbonization stability of the polymer is improved, and the flame retardant property of the high polymer material added with the flame retardant is improved.

Drawings

FIG. 1 shows the preparation of example 1 of the present invention without adding TiO₂TEM images of the products of phosphorus-nitrogen-silicon of (2) at a magnification of 5000 times with a scale of 1 μm.

FIG. 2 shows the synthetic routes of VP3, DPNSi and DPASi in the experimental example of the present invention.

Detailed Description

The technical solution of the present invention is further illustrated and described by the following examples.

Example 1

Preparation of VP 3: placing 2.6g of vanillin in 50mL of analytically pure first solvent chloroform, adding 2mL of triethylamine, slowly dropwise adding 0.90g of phosphorus oxychloride, stirring for 2h, heating to 50 ℃ for reaction for 9 h, cooling to room temperature, pouring 200mL of petroleum ether, separating out a white precipitate, stirring for half an hour, washing with ethanol for multiple times, and filtering to obtain a white solid; vacuum drying the obtained solid at 70 deg.C to constant weight to obtain white powder, which is obtained phosphorus-containing VP 3;

preparation of DPASi: 2g of dichlorodiphenylsilane was dissolved in 30mL of acetone as a second solvent, and slowly added dropwise to 50mL of 2.18g K₂CO₃And 2.32g of p-nitrophenol in a second solvent acetone, refluxing, condensing and heating to 45 ℃, reacting for 48 hours, carrying out suction filtration on the reaction liquid to obtain a solid filter cake, washing the filter cake for multiple times by using deionized water and the second solvent acetone, and carrying out vacuum drying at 60 ℃ to obtain a product DPNSi; dissolving 1g of DPNSi in 100mL of third solvent ethanol in a three-neck flask, adding 500mg of palladium-carbon, performing ultrasonic dispersion uniformly, introducing nitrogen, refluxing and condensing the reaction system, heating to 80 ℃, and dripping 20mL of hydrazine hydrate ethanol solution (the hydrazine hydrate concentration is 80 wt.%) into a constant-pressure dropping funnel to react for 48 hours; spreading a layer of aluminum oxide and a layer of silicon powder on filter paper to remove palladium carbon, dripping reaction liquid on the filter paper after the system is naturally cooled to room temperature, obtaining filtrate through suction filtration, adding a proper amount of deionized water into the filtrate, stirring for 6 hours, filtering an obtained suspension through suction filtration to obtain a solid product, washing the solid product with deionized water for multiple times, and obtaining a product DPASi through freeze-drying;

preparation of VPASi: adding 40mL of ethyl acetate into a single-neck flask, dissolving 1g of VP3, dissolving 1.2g of DPASi into 20mL of ethyl acetate solution, adding the solution into a constant-pressure dropping funnel, slowly dropping the solution into the flask, reacting at room temperature for 0.5h, and precipitating a solid product from the reaction solution; filtering the obtained solid product by suction filtration, washing with ethyl acetate for multiple times, washing with ethanol for multiple times, and vacuum drying at 60 deg.C to constant weight to obtain powder product without TiO₂A product of phosphorus nitrogen silicon.

When the product of the embodiment is added into an E-51 type epoxy resin for curing, the limit oxygen index of the epoxy resin is improved from 26% to 27.6% when the addition amount of the product is 2%.

Example 2

Preparation of VP 3: placing 2.6g of vanillin in 50mL of analytically pure first solvent chloroform, adding 2mL of triethylamine, slowly dropwise adding 0.90g of phosphorus oxychloride, stirring for 2h, heating to 50 ℃ for reaction for 9 h, cooling to room temperature, pouring 200mL of petroleum ether, separating out a white precipitate, stirring for half an hour, washing with ethanol for multiple times, and filtering to obtain a white solid; vacuum drying the obtained solid at 70 deg.C to constant weight to obtain white powder, which is obtained phosphorus-containing VP 3;

preparation of DPASi: 2g of dichlorodiphenylsilane was dissolved in 30mL of acetone as a second solvent, and slowly added dropwise to 50mL of 2.18g K₂CO₃And 2.32g of p-nitrophenol in a second solvent acetone, refluxing, condensing and heating to 45 ℃, reacting for 48 hours, carrying out suction filtration on the reaction liquid to obtain a solid filter cake, washing the filter cake for multiple times by using deionized water and the second solvent acetone, and carrying out vacuum drying at 60 ℃ to obtain a product DPNSi; dissolving 1g of DPNSi in 100mL of third solvent ethanol in a three-neck flask, adding 500mg of palladium-carbon, performing ultrasonic dispersion uniformly, introducing nitrogen, refluxing and condensing the reaction system, heating to 80 ℃, and dripping 20mL of hydrazine hydrate ethanol solution (the hydrazine hydrate concentration is 80 wt.%) into a constant-pressure dropping funnel to react for 48 hours; spreading a layer of aluminum oxide and a layer of silicon powder on filter paper to remove palladium carbon, dripping reaction liquid on the filter paper after the system is naturally cooled to room temperature, obtaining filtrate through suction filtration, adding a proper amount of deionized water into the filtrate, stirring for 6 hours, filtering an obtained suspension through suction filtration to obtain a solid product, washing the solid product with deionized water for multiple times, and obtaining a product DPASi through freeze-drying;

③ dissolving 20mL of ethyl acetate solution containing 0.4g of titanium dioxide nano-particles after being ultrasonically dispersed for 24 hours into 1g of VP3 in a single-neck flask, additionally dissolving 1.2g of DPASi into 20mL of ethyl acetate solution, adding the solution into a constant-pressure dropping funnel, slowly dropping the solution into the flask, reacting for 0.5 hour at room temperature, and precipitating a solid product out of the reaction solution; and filtering the obtained solid product through suction filtration, washing the solid product with ethyl acetate for multiple times, washing the solid product with ethanol for multiple times, and drying the solid product in vacuum at the temperature of 60 ℃ until the weight of the solid product is constant to obtain a powder product, namely the prepared phosphorus-nitrogen-silicon-containing titanium dioxide hybrid nano particle flame retardant VPASi.

VPASi is added into E-51 type epoxy resin for curing, and when the addition amount is 2%, the limiting oxygen index of the epoxy resin is improved from 26% to 29.2%.

Example 3

Preparation of VP 3: placing 2.6g of vanillin in 50mL of analytically pure first solvent chloroform, adding 2mL of triethylamine, slowly dropwise adding 0.90g of phosphorus oxychloride, stirring for 2h, heating to 50 ℃ for reaction for 9 h, cooling to room temperature, pouring 200mL of petroleum ether, separating out a white precipitate, stirring for half an hour, washing with ethanol for multiple times, and filtering to obtain a white solid; vacuum drying the obtained solid at 70 deg.C to constant weight to obtain white powder, which is obtained phosphorus-containing VP 3;

preparation of DPASi: 2g of dichlorodiphenylsilane was dissolved in 30mL of acetone as a second solvent, and slowly added dropwise to 50mL of 2.18g K₂CO₃And 2.32g of p-nitrophenol in a second solvent acetone, refluxing, condensing and heating to 45 ℃, reacting for 48 hours, carrying out suction filtration on the reaction liquid to obtain a solid filter cake, washing the filter cake for multiple times by using deionized water and the second solvent acetone, and carrying out vacuum drying at 60 ℃ to obtain a product DPNSi; dissolving 1g of DPNSi in 100mL of third solvent ethanol in a three-neck flask, adding 500mg of palladium-carbon, performing ultrasonic dispersion uniformly, introducing nitrogen, refluxing and condensing the reaction system, heating to 80 ℃, and dripping 20mL of hydrazine hydrate ethanol solution (the hydrazine hydrate concentration is 80 wt.%) into a constant-pressure dropping funnel to react for 48 hours; spreading a layer of aluminum oxide and a layer of silicon powder on filter paper to remove palladium carbon, dripping reaction liquid on the filter paper after the system is naturally cooled to room temperature, obtaining filtrate through suction filtration, adding a proper amount of deionized water into the filtrate, stirring for 6 hours, filtering an obtained suspension through suction filtration to obtain a solid product, washing the solid product with deionized water for multiple times, and obtaining a product DPASi through freeze-drying;

③ dissolving 20mL of ethyl acetate solution containing 0.4g of titanium dioxide nano-particles which is ultrasonically dispersed for 24 hours into 1.2g of VP3 in a single-neck flask, dissolving 1.44g of DPASi into 20mL of ethyl acetate solution, adding the solution into a constant-pressure dropping funnel, slowly dropping the solution into the flask, reacting for 0.5 hour at room temperature, and precipitating a solid product from the reaction solution; and filtering the obtained solid product through suction filtration, washing the solid product with ethyl acetate for multiple times, washing the solid product with ethanol for multiple times, and drying the solid product in vacuum at the temperature of 60 ℃ until the weight of the solid product is constant to obtain a powder product, namely the prepared phosphorus-nitrogen-silicon-containing titanium dioxide hybrid nano particle flame retardant VPASi.

VPASi is added into E-51 type epoxy resin for curing, and when the addition amount is 2%, the limiting oxygen index of the epoxy resin is improved from 26% to 29.8%.

Example 4

Preparation of VP 3: placing 2.6g of vanillin in 50mL of analytically pure first solvent chloroform, adding 2mL of triethylamine, slowly dropwise adding 0.90g of phosphorus oxychloride, stirring for 2h, heating to 50 ℃ for reaction for 9 h, cooling to room temperature, pouring 200mL of petroleum ether, separating out a white precipitate, stirring for half an hour, washing with ethanol for multiple times, and filtering to obtain a white solid; vacuum drying the obtained solid at 70 deg.C to constant weight to obtain white powder, which is obtained phosphorus-containing VP 3;

preparation of DPASi: 2g of dichlorodiphenylsilane was dissolved in 30mL of acetone as a second solvent, and slowly added dropwise to 50mL of 2.18g K₂CO₃And 2.32g of p-nitrophenol in a second solvent acetone, refluxing, condensing and heating to 45 ℃, reacting for 48 hours, carrying out suction filtration on the reaction liquid to obtain a solid filter cake, washing the filter cake for multiple times by using deionized water and the second solvent acetone, and carrying out vacuum drying at 60 ℃ to obtain a product DPNSi; dissolving 1g of DPNSi in 100mL of third solvent ethanol in a three-neck flask, adding 500mg of palladium-carbon, performing ultrasonic dispersion uniformly, introducing nitrogen, refluxing and condensing the reaction system, heating to 80 ℃, and dripping 20mL of hydrazine hydrate ethanol solution (the hydrazine hydrate concentration is 80 wt.%) into a constant-pressure dropping funnel to react for 48 hours; spreading a layer of aluminum oxide and a layer of silicon powder on filter paper to remove palladium carbon, dripping reaction liquid on the filter paper after the system is naturally cooled to room temperature, obtaining filtrate through suction filtration, adding a proper amount of deionized water into the filtrate, stirring for 6 hours, filtering an obtained suspension through suction filtration to obtain a solid product, washing the solid product with deionized water for multiple times, and obtaining a product DPASi through freeze-drying;

③ dissolving 20mL of ethyl acetate solution containing 0.4g of titanium dioxide nano-particles which is ultrasonically dispersed for 24 hours into 1.4g of VP3 in a single-neck flask, dissolving 1.68g of DPASi into 20mL of ethyl acetate solution, adding the solution into a constant-pressure dropping funnel, slowly dropping the solution into the flask, reacting for 0.5 hour at room temperature, and precipitating a solid product from the reaction solution; and filtering the obtained solid product through suction filtration, washing the solid product with ethyl acetate for multiple times, washing the solid product with ethanol for multiple times, and drying the solid product in vacuum at the temperature of 60 ℃ until the weight of the solid product is constant to obtain a powder product, namely the prepared phosphorus-nitrogen-silicon-containing titanium dioxide hybrid nano particle flame retardant VPASi.

VPASi is added into E-51 type epoxy resin for curing, and when the addition amount is 2%, the limiting oxygen index of the epoxy resin is improved from 26% to 29.3%.

Example 5

Preparation of VP 3: placing 2.6g of vanillin in 50mL of analytically pure first solvent chloroform, adding 2mL of triethylamine, slowly dropwise adding 0.90g of phosphorus oxychloride, stirring for 2h, heating to 50 ℃ for reaction for 9 h, cooling to room temperature, pouring 200mL of petroleum ether, separating out a white precipitate, stirring for half an hour, washing with ethanol for multiple times, and filtering to obtain a white solid; vacuum drying the obtained solid at 70 deg.C to constant weight to obtain white powder, which is obtained phosphorus-containing VP 3;

preparation of DPASi: 2g of dichlorodiphenylsilane was dissolved in 30mL of acetone as a second solvent, and slowly added dropwise to 50mL of 2.18g K₂CO₃And 2.32g of p-nitrophenol in a second solvent acetone, refluxing, condensing and heating to 45 ℃, reacting for 48 hours, carrying out suction filtration on the reaction liquid to obtain a solid filter cake, washing the filter cake for multiple times by using deionized water and the second solvent acetone, and carrying out vacuum drying at 60 ℃ to obtain a product DPNSi; dissolving 1g of DPNSi in 100mL of third solvent ethanol in a three-neck flask, adding 500mg of palladium-carbon, performing ultrasonic dispersion uniformly, introducing nitrogen, refluxing and condensing the reaction system, heating to 80 ℃, and dripping 20mL of hydrazine hydrate ethanol solution (the hydrazine hydrate concentration is 80 wt.%) into a constant-pressure dropping funnel to react for 48 hours; spreading a layer of aluminum oxide and a layer of silicon powder on filter paper for removing palladium carbon, dripping reaction liquid on the filter paper after the system is naturally cooled to room temperature, obtaining filtrate through suction filtration, adding a proper amount of deionized water into the filtrate, stirring for 6 hours, filtering out a solid product from obtained suspension through suction filtration, washing the solid product with deionized water for multiple times, and obtaining the palladium carbon through freeze-dryingA product DPASi;

③ dissolving 20mL of ethyl acetate solution containing 0.4g of titanium dioxide nano-particles which is ultrasonically dispersed for 24 hours into 1.6g of VP3 in a single-neck flask, dissolving 1.92g of DPASi into 20mL of ethyl acetate solution, adding the solution into a constant-pressure dropping funnel, slowly dropping the solution into the flask, reacting for 0.5 hour at room temperature, and precipitating a solid product from the reaction solution; and filtering the obtained solid product through suction filtration, washing the solid product with ethyl acetate for multiple times, washing the solid product with ethanol for multiple times, and drying the solid product in vacuum at the temperature of 60 ℃ until the weight of the solid product is constant to obtain a powder product, namely the prepared phosphorus-nitrogen-silicon-containing titanium dioxide hybrid nano particle flame retardant VPASi.

VPASi is added into E-51 type epoxy resin for curing, and when the addition amount is 2%, the limiting oxygen index of the epoxy resin is improved from 26% to 28.9%.

Example 6

0.4g of titanium dioxide nano-particles are added into the E-51 type epoxy resin to be uniformly dispersed and then cured, and when the adding amount is 2%, the limit oxygen index of the epoxy resin is improved from 26% to 27.9%.

From the above examples, it can be seen that, under the same addition amount, compared with the titanium dioxide hybrid nanoparticles without TiO, the silicon titanium dioxide hybrid nanoparticles containing phosphorus, nitrogen and silicon are added₂The product containing phosphorus, nitrogen and silicon (as comparative example 1) and pure titanium dioxide nano particles (as comparative example 6) have better flame retardant property for a polymer matrix.

The above description is only a preferred embodiment of the present invention, and therefore should not be taken as limiting the scope of the invention, which is defined by the appended claims and their equivalents.