阅读说明：本技术 一种单宁酸-磷腈网络功能化水滑石基阻燃剂及其制备方法 (Tannin-phosphazene network functionalized hydrotalcite-based flame retardant and preparation method thereof ) 是由 徐圣 田贤曜 曾虹燕 吴昆� 胡杰 钟承志 颜文娟 王晗 郭一卉 马嘉欣 于 2021-01-05 设计创作，主要内容包括：本发明公开了一种单宁酸-磷腈网络功能化水滑石基阻燃剂,包括以下原料：水滑石、单宁酸、三乙胺和六氯环三磷腈；制备方法：(1)称取各原料；(2)将水滑石超声分散于无水乙醇中,备用；(3)先将单宁酸和三乙胺超声分散于有机溶剂中,然后加入水滑石悬浮液中；(4)先将六氯环三磷腈超声分散于有机溶剂中,然后逐滴加入水滑石混合液中,升温反应,过滤,真空干燥,研磨,即得。本发明实现了膨胀型阻燃体系与层状水滑石复合阻燃剂的制备,操作简单、易行,阻燃剂具有优异的阻燃的性能,且抑烟效果显著,符合现今人们要求阻燃剂绿色可持续的趋势。(The invention discloses a tannin-phosphazene network functionalized hydrotalcite-based flame retardant, which comprises the following raw materials: hydrotalcite, tannic acid, triethylamine and hexachlorocyclotriphosphazene; the preparation method comprises the following steps: (1) weighing the raw materials; (2) ultrasonically dispersing hydrotalcite in absolute ethyl alcohol for later use; (3) firstly, ultrasonically dispersing tannic acid and triethylamine in an organic solvent, and then adding the organic solvent into a hydrotalcite suspension; (4) firstly, ultrasonically dispersing hexachlorocyclotriphosphazene in an organic solvent, then dropwise adding the organic solvent into a hydrotalcite mixed solution, heating for reaction, filtering, drying in vacuum, and grinding to obtain the catalyst. The preparation method realizes the preparation of the intumescent flame retardant system and layered hydrotalcite composite flame retardant, is simple and easy to operate, has excellent flame retardant performance and obvious smoke suppression effect, and meets the current trend that people require the flame retardant to be green and sustainable.)

1. A tannin-phosphazene network functionalized hydrotalcite-based flame retardant is characterized by comprising the following raw materials: hydrotalcite, tannic acid, triethylamine and hexachlorocyclotriphosphazene;

the mass ratio of the hydrotalcite to the hexachlorocyclotriphosphazene is (3-10): 1;

the molar ratio of the tannic acid to the triethylamine to the hexachlorocyclotriphosphazene is (0.5-3): (5-10): 1.

2. The tannin-phosphazene network functionalized hydrotalcite-based flame retardant of claim 1, wherein the hydrotalcite comprises the following raw materials: trivalent metal salts, divalent metal salts and urea;

the molar ratio of the cations in the trivalent metal salt to the cations in the divalent metal salt is 1 (0.5-3);

the ratio of the sum of the moles of anions in the trivalent metal salt and the divalent metal salt to the moles of urea is 1: (2.5-4.5).

3. The tannin-phosphazene network functionalized hydrotalcite-based flame retardant of claim 2, wherein the trivalent metal salt is any one of an aluminum salt, an iron salt and a chromium salt;

any one of magnesium salt, zinc salt, nickel salt, cobalt salt, manganese salt and copper salt of the divalent metal salt.

4. A preparation method of a tannin-phosphazene network functionalized hydrotalcite-based flame retardant is characterized by comprising the following steps:

(1) weighing the raw materials according to the molar ratio of the tannin-phosphazene network functionalized hydrotalcite-based flame retardant of any one of claims 1 to 3;

(2) ultrasonically dispersing hydrotalcite in absolute ethyl alcohol to obtain hydrotalcite suspension for later use;

(3) firstly, ultrasonically dispersing tannic acid and triethylamine in an organic solvent, and then adding the organic solvent into a hydrotalcite suspension to obtain a hydrotalcite mixed solution for later use;

(4) firstly, ultrasonically dispersing hexachlorocyclotriphosphazene in an organic solvent, then dropwise adding the organic solvent into a hydrotalcite mixed solution, heating for reaction, filtering, drying in vacuum, and grinding to obtain the tannin-phosphazene network functionalized hydrotalcite-based flame retardant.

5. The method for preparing the tannin-phosphazene network functionalized hydrotalcite-based flame retardant according to claim 4, wherein in the step (2), the method for preparing the hydrotalcite is as follows:

A. dissolving trivalent metal salt, divalent metal salt and urea in deionized water to obtain a mixed salt solution containing trivalent metal ions and divalent metal ions of urea;

B. heating the mixed salt solution to 80-120 ℃ for reaction to obtain hydrotalcite precipitate reaction liquid;

C. and filtering, washing and vacuum drying the reaction liquid of the hydrotalcite precipitate to obtain the hydrotalcite.

6. The method for preparing the tannin-phosphazene network functionalized hydrotalcite-based flame retardant of claim 5, wherein in the step A, the concentration of the trivalent metal salt in the deionized water is 0.02-0.025 mol-L^-1；

In the step B, the reaction time is 8-24 h;

in the step C, the temperature of the vacuum drying is 40-80 ℃, and the time is 8-24 h.

7. The method for preparing the tannin-phosphazene network functionalized hydrotalcite-based flame retardant according to claim 4, wherein in the steps (2) to (4), the power of the ultrasonic dispersion is 50-200W, and the time is 5-10 min.

8. The method for preparing the tannin-phosphazene network functionalized hydrotalcite-based flame retardant according to claim 4, wherein in the step (2), the volume ratio of the mass of the hydrotalcite to the absolute ethyl alcohol is 5 g: 100 mL;

in the step (3), the concentration of tannic acid in the organic solvent is 0.015 to 0.025 mol.L^-1；

In the step (4), the concentration of hexachlorocyclotriphosphazene in the organic solvent is 0.05-0.2 mol.L^-1。

9. The method for preparing the tannin-phosphazene network functionalized hydrotalcite-based flame retardant according to claim 8, wherein in the steps (3) and (4), the organic solvent is at least one of acetonitrile, tetrahydrofuran, acetone and pyridine.

10. The method for preparing the tannin-phosphazene network functionalized hydrotalcite-based flame retardant according to the claim 4, wherein in the step (4), the dropwise adding time is more than 20 min;

heating to 30-50 ℃;

the reaction time is 5-8 h;

the temperature of the vacuum drying is 40-80 ℃, and the time is 8-24 h;

the grinding is carried out until the particle size is 1-4 mu m.

Technical Field

The invention relates to the technical field of flame retardants, in particular to a tannin-phosphazene network functionalized hydrotalcite-based flame retardant and a preparation method thereof.

Background

The flame retardant is a functional additive for endowing a flammable polymer with flame retardancy, is mainly designed aiming at the flame retardancy of a high polymer material, and is divided into an additive flame retardant and a reactive flame retardant according to a using method. The additive flame retardant is added into the polymer by a mechanical mixing method to enable the polymer to have flame retardance, and has a wide application range.

The hydrotalcite compound is a novel multi-effect plastic additive, has multiple functions of flame retardance, smoke abatement, filling and the like as a flame retardant, and is a novel inorganic flame retardant with high efficiency, no halogen, low smoke and no toxicity. For the high molecular polymer which is extremely easy to burn, a thicker and more compact carbon layer is quickly formed during burning, so that the high molecular polymer plays an important role in isolating the exchange of oxygen and heat and further preventing the further progress of burning. In addition, metal oxide formed after the hydrotalcite is combusted and polymer form a compact carbonaceous layer, so that fire hazard can be effectively reduced.

However, the mere addition of talc tends to cause agglomeration due to poor dispersibility, and the amount of talc added is generally required to be large to satisfy the flame retardancy requirement.

Therefore, how to modify hydrotalcite is a problem that needs to be solved by those skilled in the art.

Disclosure of Invention

In view of the above, the present invention aims to provide a tannin-phosphazene network functionalized hydrotalcite-based flame retardant and a preparation method thereof, so as to solve the defects in the prior art.

In order to achieve the purpose, the invention adopts the following technical scheme:

a tannin-phosphazene network functionalized hydrotalcite-based flame retardant (LDH @ TA-HP) comprises the following raw materials: hydrotalcite (LDH), Tannic Acid (TA), Triethylamine (TEA), and Hexachlorocyclotriphosphazene (HP); wherein the mass ratio of the hydrotalcite to the hexachlorocyclotriphosphazene is (3-10): 1, the molar ratio of the tannic acid to the triethylamine to the hexachlorocyclotriphosphazene is (0.5-3) to (5-10) to 1.

The invention has the beneficial effects that: the phosphazene derivative (a new substance synthesized by hexachlorocyclotriphosphazene monomer) is used as a novel halogen-free flame retardant, has the characteristics of environmental friendliness, high compatibility with polymers, excellent flame retardant property and the like, the high nitrogen and phosphorus content of the material can be used as an acid source and a gas source, the invention takes hexachlorocyclotriphosphazene as a monomer for forming polyphosphazene, hydrotalcite is used as a template for modifying the surface of polyphosphazene, tannic acid is used as a curing agent of polyphosphazene, triethylamine is used as a pH buffering agent, hexachlorocyclotriphosphazene and monophosphoric acid (tannin) with a polyaromatic ring structure are creatively used as a charring agent to form an intumescent flame retardant system, and then the charring agent is introduced to the surface of hydrotalcite, the advantages of the two can be combined to obtain a novel tannin-phosphazene network functionalized hydrotalcite-based flame retardant, and the novel tannin-phosphazene network functionalized hydrotalcite-based flame retardant is applied to flame-retardant composite materials and has important industrial value.

Further, the hydrotalcite comprises the following raw materials: trivalent metal salts, divalent metal salts and urea; wherein the molar ratio of the cations in the trivalent metal salt to the cations in the divalent metal salt is 1 (0.5-3), and the ratio of the sum of the molar numbers of the anions in the trivalent metal salt and the divalent metal salt to the molar number of the urea is 1: (2.5-4.5).

The beneficial effects of the further technical scheme are that the divalent metal salt and the trivalent metal salt meet the necessary conditions for preparing the hydrotalcite, and the hydrotalcite prepared by the urea method has higher crystallinity.

Further, the trivalent metal salt is any one of aluminum salt, iron salt and chromium salt; any one of magnesium salt, zinc salt, nickel salt, cobalt salt, manganese salt and copper salt of divalent metal salt.

The beneficial effect of adopting the further technical scheme is that the divalent metal salt and the trivalent metal salt selected by the invention can form a stable hydrotalcite structure.

A preparation method of a tannin-phosphazene network functionalized hydrotalcite-based flame retardant specifically comprises the following steps:

(1) weighing the raw materials according to the molar ratio of the tannin-phosphazene network functionalized hydrotalcite-based flame retardant;

(2) ultrasonically dispersing hydrotalcite in absolute ethyl alcohol to obtain hydrotalcite suspension for later use;

(3) firstly, ultrasonically dispersing tannic acid and triethylamine in an organic solvent, and then adding the organic solvent into a hydrotalcite suspension to obtain a hydrotalcite mixed solution for later use;

(4) firstly, ultrasonically dispersing hexachlorocyclotriphosphazene in an organic solvent, then dropwise adding the organic solvent into a hydrotalcite mixed solution, heating for reaction, filtering, drying in vacuum, and grinding to obtain the tannin-phosphazene network functionalized hydrotalcite-based flame retardant.

The invention has the beneficial effects that: the tannin-phosphazene polymer network with a highly-cyclic cross-linked structure is synthesized on the surface of the hydrotalcite, so that the surface energy of the hydrotalcite is improved while an intumescent flame retardant system is introduced, the agglomeration of the hydrotalcite is hindered, the dispersibility of a flame retardant in a polymer matrix is further improved, the excellent flame retardant and smoke suppression effects of the hydrotalcite are combined with the intumescent flame retardant system, and the flame retardant property of the hydrotalcite on the polymer matrix is further improved.

Further, in the step (2), the preparation method of the hydrotalcite is as follows: A. dissolving trivalent metal salt, divalent metal salt and urea in deionized water to obtain trivalent metal ions and divalent metal ions containing ureaA mixed salt solution of a valence metal ion; B. heating the mixed salt solution to 80-120 ℃ for reaction to obtain hydrotalcite precipitate reaction liquid; C. and filtering, washing and vacuum drying the reaction liquid of the hydrotalcite precipitate to obtain the hydrotalcite. Furthermore, in the step A, the concentration of the trivalent metal salt in the deionized water is 0.02-0.025 mol.L^-1(ii) a In the step B, the reaction time is 8-24 h; the vacuum drying temperature is 40-80 deg.C, and the drying time is 8-24 h.

The further technical scheme has the beneficial effects that the urea is slowly decomposed by heating reaction to improve the pH value of the mixed solution, so that cations are precipitated to form hydrotalcite and are fully crystallized; the hydrotalcite prepared by the method has the advantages of complete grain development, small granularity and the like, and is uniform in distribution and light in particle agglomeration.

Further, in the steps (2) to (4), the power of ultrasonic dispersion is 50-200W, and the time is 5-10 min; in the step (2), the volume ratio of the mass of the hydrotalcite to the absolute ethyl alcohol is 5 g: 100 mL.

The further technical scheme has the beneficial effects that in the steps (2) and (3), the hydrotalcite can be prevented from agglomerating through ultrasonic dispersion, so that the hexachlorocyclotriphosphazene can better modify the surface of the hydrotalcite; in the step (4), the hexachlorocyclotriphosphazene can be fully dissolved in the organic solvent through ultrasonic dispersion.

Further, in the steps (3) and (4), the organic solvent is at least one of acetonitrile, tetrahydrofuran, acetone and pyridine.

The further technical scheme has the beneficial effects that the organic solvent selected by the invention can better dissolve reactants, so that the polymerization reaction can be smoothly carried out.

Further, in the step (4), the dropwise adding time is more than 20 min; heating to 30-50 deg.C; the reaction time is 5-8 h; the temperature of vacuum drying is 40-80 ℃, and the time is 8-24 h; grinding to particle size of 1-4 μm.

The further technical scheme has the advantages that the reaction rate can be controlled by dropwise adding, and the utilization rate of reactants is improved; the polymerization of the reactants can be promoted by raising the temperature; vacuum drying to remove excessive solvent; grinding prevents the product from agglomerating.

According to the technical scheme, compared with the prior art, the invention has the following beneficial effects:

the preparation method realizes the preparation of the intumescent flame retardant system and layered hydrotalcite composite flame retardant, is simple and easy to operate, has excellent flame retardant performance and obvious smoke suppression effect, and meets the current trend that people require the flame retardant to be green and sustainable.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

FIG. 1 is a scheme showing the synthetic scheme for preparing LDH @ TA-HP in examples 1-3 of the present invention;

FIG. 2 is an infrared spectrum of LDH and LDH @ TA-HP prepared in example 1 of the present invention;

FIG. 3 is an SEM image of LDH and LDH @ TA-HP prepared in example 1 of the present invention;

FIG. 4 is an XRD pattern of LDH and LDH @ TA-HP prepared in example 2 of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

The tannin-phosphazene network functionalized hydrotalcite-based flame retardant comprises the following raw materials by weight: 2.78g of hydrotalcite, 5.1g of tannic acid, 3.9mL of triethylamine and 0.695g of hexachlorocyclotriphosphazene, namely, the mass ratio of the hydrotalcite to the hexachlorocyclotriphosphazene is 4:1, and the molar ratio of the tannic acid, the triethylamine and the hexachlorocyclotriphosphazene is 1.5:5: 1;

wherein, the hydrotalcite comprises the following raw materials by weight: trivalent metal salt Al (NO)₃)₃·9H₂O9.38 g, divalent metal salt Mg (NO)₃)₂·6H₂12.82g of O and 34.65g of urea, namely, the molar ratio of the cation in the trivalent metal salt to the cation in the divalent metal salt is 1:2, and the ratio of the sum of the molar numbers of the anions in the trivalent metal salt and the divalent metal salt to the molar number of the urea is 1: 3.3.

The preparation method of the tannin-phosphazene network functionalized hydrotalcite-based flame retardant has a synthesis route diagram shown in figure 1 (firstly synthesizing hydrotalcite and then performing polyphosphazene microencapsulation on the surface of the hydrotalcite), and specifically comprises the following steps:

(1) weighing the raw materials according to the weight of the tannin-phosphazene network functionalized hydrotalcite-based flame retardant;

(2) ultrasonically dispersing hydrotalcite in 150mL of absolute ethyl alcohol with the power of 100W for 5min to obtain hydrotalcite suspension for later use;

the preparation method of the hydrotalcite comprises the following steps: A. adding trivalent metal salt Al (NO)₃)₃·9H₂O, divalent metal salt Mg (NO)₃)₂·6H₂Dissolving O and urea in 400mL of deionized water, and ultrasonically dissolving for 5min at the ultrasonic power of 100W to obtain a mixed salt solution containing trivalent metal ions and divalent metal ions of urea; B. after the ultrasonic treatment is finished, transferring the mixed salt solution into a reaction kettle, putting the reaction kettle into an oven, and reacting for 24 hours at the set temperature of 110 ℃ to obtain hydrotalcite precipitate reaction liquid; C. filtering and washing reaction liquid of the hydrotalcite precipitate, and drying the reaction liquid for 24 hours in vacuum at 40 ℃ to obtain hydrotalcite (LDH);

(3) firstly, ultrasonically dispersing tannic acid and triethylamine in 80mL of acetonitrile at the power of 100W for 10min, then adding the mixture into a hydrotalcite suspension, and continuously ultrasonically stirring at the ultrasonic power of 100W to obtain a hydrotalcite mixed solution for later use;

(4) firstly, ultrasonically dispersing hexachlorocyclotriphosphazene in 70mL of acetonitrile at the power of 100W for 5min, then dropwise adding into a hydrotalcite mixed solution for 30min, continuously ultrasonically stirring at the ultrasonic power of 100W, setting the temperature under an oil bath to be 40 ℃ after the dropwise adding is finished, reacting for 6h, continuously stirring in the process, filtering and washing a product after the reaction is finished, carrying out vacuum drying at the temperature of 40 ℃ for 24h, and grinding to the particle size of 1 mu m to obtain the tannin-phosphazene network functionalized hydrotalcite-based flame retardant (LDH @ TA-HP).

Example 2

The tannin-phosphazene network functionalized hydrotalcite-based flame retardant comprises the following raw materials by weight: 2.085g of hydrotalcite, 5.1g of tannic acid, 7.8mL of triethylamine and 0.695g of hexachlorocyclotriphosphazene, namely, the mass ratio of the hydrotalcite to the hexachlorocyclotriphosphazene is 3:1, and the molar ratio of the tannic acid, the triethylamine and the hexachlorocyclotriphosphazene is 1.5:10: 1;

wherein, the hydrotalcite comprises the following raw materials by weight: trivalent metal salt Al (NO)₃)₃·9H₂O9.38 g, divalent metal salt Zn (NO)₃)₂·6H₂14.57g of O and 42g of urea, namely, the molar ratio of the cation in the trivalent metal salt to the cation in the divalent metal salt is 1:2, and the ratio of the sum of the moles of the anion in the trivalent metal salt and the divalent metal salt to the moles of the urea is 1: 4.

the preparation method of the tannin-phosphazene network functionalized hydrotalcite-based flame retardant has a synthesis route diagram shown in figure 1 (firstly synthesizing hydrotalcite and then performing polyphosphazene microencapsulation on the surface of the hydrotalcite), and specifically comprises the following steps:

(1) weighing the raw materials according to the weight of the tannin-phosphazene network functionalized hydrotalcite-based flame retardant;

(2) ultrasonically dispersing hydrotalcite in 150mL of absolute ethyl alcohol with the power of 100W for 5min to obtain hydrotalcite suspension for later use;

the preparation method of the hydrotalcite comprises the following steps: A. adding trivalent metal salt Al (NO)₃)₃·9H₂O, divalent metal salt Zn (NO)₃)₂·6H₂Dissolving O and urea in 400mL of deionized water, and ultrasonically dissolving for 5min at the ultrasonic power of 100W to obtain a mixed salt solution containing trivalent metal ions and divalent metal ions of urea; B. transferring the mixed salt solution into a reaction kettle, putting the reaction kettle into an oven, setting the temperature at 120 ℃ for reacting for 18h,obtaining hydrotalcite precipitate reaction liquid; C. filtering and washing reaction liquid of the hydrotalcite precipitate, and drying the reaction liquid for 12 hours in vacuum at the temperature of 60 ℃ to obtain hydrotalcite (LDH);

(3) firstly, ultrasonically dispersing tannic acid and triethylamine in 80mL of acetonitrile at the power of 100W for 10min, then adding the mixture into a hydrotalcite suspension, and continuously ultrasonically stirring at the ultrasonic power of 100W to obtain a hydrotalcite mixed solution for later use;

(4) firstly, ultrasonically dispersing hexachlorocyclotriphosphazene in 70mL of acetonitrile at the power of 100W for 5min, then dropwise adding into a hydrotalcite mixed solution for 30min, continuously ultrasonically stirring at the ultrasonic power of 100W, setting the temperature under an oil bath to be 40 ℃ after the dropwise adding is finished, reacting for 6h, continuously stirring in the process, filtering and washing a product after the reaction is finished, carrying out vacuum drying at the temperature of 60 ℃ for 12h, and grinding to the particle size of 3 mu m to obtain the tannin-phosphazene network functionalized hydrotalcite-based flame retardant (LDH @ TA-HP).

Example 3

The tannin-phosphazene network functionalized hydrotalcite-based flame retardant comprises the following raw materials by weight: 2.78g of hydrotalcite, 5.1g of tannic acid, 3.9mL of triethylamine and 0.695g of hexachlorocyclotriphosphazene, namely, the mass ratio of the hydrotalcite to the hexachlorocyclotriphosphazene is 4:1, and the molar ratio of the tannic acid, the triethylamine and the hexachlorocyclotriphosphazene is 1.5:5: 1;

wherein, the hydrotalcite comprises the following raw materials by weight: trivalent metal salt Al (NO)₃)₃·9H₂O9.38 g, divalent metal salt Ni (NO)₃)₂·6H₂O21.809 g and urea 33.75g, namely, the molar ratio of the cation in the trivalent metal salt to the cation in the divalent metal salt is 1:3, the ratio of the sum of the moles of the anion in the trivalent metal salt and the divalent metal salt to the moles of the urea is 1: 2.5.

the preparation method of the tannin-phosphazene network functionalized hydrotalcite-based flame retardant has a synthesis route diagram shown in figure 1 (firstly synthesizing hydrotalcite and then performing polyphosphazene microencapsulation on the surface of the hydrotalcite), and specifically comprises the following steps:

(1) weighing the raw materials according to the weight of the tannin-phosphazene network functionalized hydrotalcite-based flame retardant;

(2) ultrasonically dispersing hydrotalcite in 150mL of absolute ethyl alcohol with the power of 100W for 5min to obtain hydrotalcite suspension for later use;

the preparation method of the hydrotalcite comprises the following steps: A. adding trivalent metal salt Al (NO)₃)₃·9H₂O, divalent metal salt Ni (NO)₃)₂·6H₂Dissolving O and urea in 400mL of deionized water, and ultrasonically dissolving for 5min at the ultrasonic power of 100W to obtain a mixed salt solution containing trivalent metal ions and divalent metal ions of urea; B. transferring the mixed salt solution into a reaction kettle, putting the reaction kettle into an oven, and reacting for 12 hours at the set temperature of 110 ℃ to obtain hydrotalcite precipitate reaction liquid; C. filtering and washing reaction liquid of the hydrotalcite precipitate, and drying the reaction liquid for 8 hours in vacuum at the temperature of 80 ℃ to obtain hydrotalcite (LDH);

(3) firstly, ultrasonically dispersing tannic acid and triethylamine in 80mL of acetonitrile at the power of 100W for 10min, then adding the mixture into a hydrotalcite suspension, and continuously ultrasonically stirring at the ultrasonic power of 100W to obtain a hydrotalcite mixed solution for later use;

(4) firstly, ultrasonically dispersing hexachlorocyclotriphosphazene in 70mL of acetonitrile at the power of 100W for 5min, then dropwise adding into a hydrotalcite mixed solution for 30min, continuously ultrasonically stirring at the ultrasonic power of 100W, setting the temperature under an oil bath to be 40 ℃ after the dropwise adding is finished, reacting for 6h, continuously stirring in the process, filtering and washing a product after the reaction is finished, vacuum drying at the temperature of 80 ℃ for 8h, and grinding to the particle size of 4 mu m to obtain the tannin-phosphazene network functionalized hydrotalcite-based flame retardant (LDH @ TA-HP).

Performance testing

FIG. 4 is an XRD pattern of LDH @ TA-HP prepared in example 2 of the present invention.

1. The LDH @ TA-HP prepared in example 1 was taken and placed in an infrared spectrometer, and the obtained infrared spectrum is shown in FIG. 2.

As can be seen from FIG. 2, the new appearance of characteristic peak in the infrared spectrum of LDH @ TA-HP indicates that the tannin-phosphazene polymer is successfully microencapsulated on the surface of hydrotalcite.

2. LDH and LDH @ TA-HP prepared in example 1 were taken and placed in a scanning electron microscope, and the SEM image is shown in FIG. 3.

As can be seen from FIG. 3, a layer of tannin-phosphazene organic polymer can be clearly observed in the SEM image of LDH @ TA-HP, indicating that LDH @ TA-HP was successfully prepared.

3. The LDH @ TA-HP prepared in example 2 was taken and placed in an X-ray diffractometer, and the XRD pattern obtained is shown in FIG. 4.

As can be seen from FIG. 4, the XRD diffraction peak of LDH @ TA-HP shows that the layered structure of hydrotalcite is retained, and the weakening of the diffraction peak further shows that the tannin-phosphazene polymer is successfully microencapsulated on the surface of the hydrotalcite.