CN112876740B

CN112876740B - Phenylboronic acid grafted and modified zirconium phosphate-based flame retardant and preparation method thereof

Info

Publication number: CN112876740B
Application number: CN202110125747.XA
Authority: CN
Inventors: 刘治田; 石遒; 霍思奇; 王成
Original assignee: Wuhan Institute of Technology
Current assignee: Wuhan Institute of Technology
Priority date: 2021-01-29
Filing date: 2021-01-29
Publication date: 2022-03-15
Anticipated expiration: 2041-01-29
Also published as: WO2022160673A1; CN112876740A

Abstract

The invention discloses a novel phenylboronic acid-silane grafted modified zirconium phosphate-based nano flame retardant, which is prepared by pretreating alpha-zirconium phosphate by using TBA (tert-butyl-phenyl-ammonium-phosphate), and chemically modifying a stripped silane-modified zirconium phosphate nanosheet by using 4-chlorobenzeneboronic acid (MSDS). The zirconium phosphate-based flame retardant disclosed by the invention can effectively play a flame-retardant synergistic effect of phosphorus-nitrogen-boron-carbon, integrates flame retardance, smoke suppression and enhancement into a whole, has a good char forming effect, does not contain halogen, is environment-friendly, and can synchronously improve the flame retardant performance of the flame retardant and the compatibility of the flame retardant with a high polymer material; and the related preparation method is simple and convenient and is suitable for popularization and application.

Description

Phenylboronic acid grafted and modified zirconium phosphate-based flame retardant and preparation method thereof

Technical Field

The invention belongs to the technical field of flame-retardant smoke-suppressing materials, and particularly relates to a phenylboronic acid grafted and modified zirconium phosphate-based flame retardant and a preparation method thereof.

Background

The layered nano material has the characteristics of small size effect, macroscopic tunnel effect and the like due to the special structure (such as a layered adjustable structure); the intercalation modification is carried out on the layered nano-material to form an intercalation type nano-composite material, and an inorganic interlayer of the composite material can be spread to form a single-sheet layered material with a large length-diameter ratio, so that the thermal stability, fire resistance, flame retardance and mechanical property of the obtained composite material can be improved. Therefore, in recent years, layered nanocomposites have become one of the hot research spots in the field of nanocomposites.

Zirconium phosphate is a layered nano material with solid acid property, has excellent chemical and thermal stability, and ZrP layers are superposed together through hydrogen bond action and van der Waals force, but because hydrogen ions ionizable from the layers have enough movement space in a microscopic space, compared with other interlayer substances, the interlayer peeling is simpler, and substances can be inserted to form a composite material. In addition, ZrP also has the characteristics of large ion exchange capacity, controllable length-diameter ratio, narrow particle size distribution, easy intercalation stripping, adjustable interlayer spacing, solid acid characteristic and the like, and is an excellent raw material for preparing the layered nano composite material. When the burning produced, single zirconium phosphate lamella can be regarded as solid acid catalytic carbonization, is showing and is promoting flame retardant efficiency, but the produced carbon-layer of single zirconium phosphate is not compact enough, and the carbonization action time is short, and the charcoal layer is not enough, can't play the effect of lasting protection charcoal layer, and this kind of defect restriction zirconium phosphate is in the application of fire-Retardant System (IFRs), leads to the fire retardant to have the thermal stability can the poor, flame retardant efficiency subalternation problem.

In order to solve the problems of low density, short action time, poor carbon layer strength and the like of a zirconium phosphate carbon layer, the patent CN110982122A introduces melamine urate into zirconium phosphate and utilizes a phosphorus-nitrogen compounding principle method to play a certain flame retardant effect, but only applies the zirconium phosphate as a reactive flame retardant to polyurethane, so that the problems of large compounding amount, limited application field, insufficient flame retardant efficiency and the like exist; in patent CN109810545A, the phosphoric acid is stripped into nanosheets and added into a flame-retardant system, the carbonization of the polymer is improved by utilizing the catalytic action of the zirconium phosphate nanosheets, and further the flame-retardant efficiency is improved, however, the agglomeration phenomenon which easily occurs to the zirconium phosphate nanosheets is not solved, and the problem of compatibility with resin is not considered, so that the flame-retardant efficiency is not ideal.

Disclosure of Invention

The invention mainly aims to solve the problems of poor char quality, low density of a carbon layer, short protection time of the carbon layer, easy flame breaking and the like of the existing zirconium phosphate flame retardant, and provides a novel nanometer flame retardant based on phenylboronic acid-silane graft modified intercalated zirconium phosphate, wherein 4-chlorobenzeneboronic acid (MSDS) is adopted to chemically modify a stripped and silane modified zirconium phosphate nanosheet, so that the flame retardant synergistic effect of phosphorus-nitrogen-boron-carbon can be effectively exerted, and the obtained flame retardant integrates flame retardance, smoke suppression and reinforcement, has good char forming effect, does not contain halogen and is environment-friendly; and the related preparation method is simple and convenient and is easy to popularize and apply.

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

a preparation method of phenylboronic acid modified zirconium phosphate based flame retardant comprises the following steps:

1) dispersing zirconium phosphate in water to prepare zirconium phosphate suspension, dropwise adding TBA at a constant speed into the zirconium phosphate suspension, uniformly stirring, and then carrying out ultrasonic treatment to obtain TBA pre-intercalation zirconium phosphate suspension; then dropwise adding concentrated phosphoric acid into the solution, reacting to obtain semitransparent gel precipitate, and washing with a solvent;

2) adding a silane coupling agent and a solvent into the washed gel precipitate, uniformly stirring and dispersing, and then carrying out heating reaction;

3) and adding triethylamine to perform ultrasonic dispersion treatment, slowly adding 4-chlorobenzene boric acid (MSDS), reacting, standing, centrifuging, filtering, washing and drying to obtain the phenylboronic acid modified zirconium phosphate based flame retardant.

In the above scheme, the zirconium phosphate is alpha-zirconium phosphate.

In the scheme, the silane coupling agent is a silane coupling agent with amino, and can be one or more of KH-550, KH-570, KH-792 and Sj-42.

In the scheme, the solvent is one or more of absolute ethyl alcohol, dioxane, tetrahydrofuran, absolute methanol and chloroform.

In the scheme, the ultrasonic treatment temperature in the step 1) is 0-20 ℃, and the time is 0.5-1 h.

In the scheme, the reaction time in the step 1) is 1-3 h.

In the scheme, the heating reaction temperature in the step 2) is 60-150 ℃, and the time is 16-24 h.

In the above scheme, the reaction conditions in step 3) include: heating and refluxing for 6-18 h, and reacting at room temperature for 12-36 h.

In the scheme, the molar ratio of the zirconium phosphate to the TBA is 100: 1-1: 50; preferably, the molar ratio of the zirconium phosphate to the TBA is 10: 1-1: 10.

In the scheme, the molar ratio of the zirconium phosphate to the silane coupling agent is 1: 3-3: 1.

In the scheme, the molar ratio of the zirconium phosphate to the 4-chlorobenzene boric acid is 2: 1-1: 20.

In the scheme, the molar ratio of the zirconium phosphate to the triethylamine (acid-binding agent) is 1 (0.5-2). .

In the scheme, the drying temperature is 60-80 ℃, and the drying time is 12-24 hours.

In the scheme, the step of the dispersion treatment in the step 4) is ultrasonic treatment for about 10 min.

In the scheme, the washing step in the step 3) is to wash for 2-3 times by adopting acetone, wash for 2-3 times by adopting ethanol and wash for 2-3 times by adopting water.

In the scheme, the concentration of the concentrated phosphoric acid is 75-90 wt%.

The flame retardant based on the grafted phenylboronic acid silane intercalation modified zirconium phosphate is prepared according to the scheme.

The principle of the invention is as follows:

according to the invention, TBA is used for pretreating alpha-zirconium phosphate, the interlayer distance of the zirconium phosphate is increased, aminosilane coupling agent is used for carrying out interlayer modification, amino groups are grafted on the interlayer surface of the alpha-zirconium phosphate, and 4-chlorobenzeneboronic acid is introduced for reaction to graft and modify phenylboronic acid groups to the interlayer of the zirconium phosphate; the silane modification of the alpha-zirconium phosphate can simultaneously improve the compatibility between the zirconium phosphate and matrix resin, and obviously improve the flame retardant efficiency of a system based on the synergistic effect of phosphorus element and boron element:

1) the phenylboronic acid is introduced into the zirconium phosphate, and the phenylboronic acid serving as a boron flame retardant can act on a condensed phase, so that the influence of heat radiation absorption of a base material in a combustion process and heat feedback from flame is reduced;

2) the phenylboronic acid and zirconium phosphate have synergistic flame-retardant characteristics under the coordination effect, the phenylboronic acid and the zirconium phosphate exist in the zirconium phosphate-based flame retardant grafted with the phenylboronic acid, the P-B synergistic effect is exerted in the fireproof process, and the phenylboronic acid and the zirconium phosphate are introduced to accelerate the generation of a carbon layer and effectively improve the flame-retardant performance of a high polymer material and the like by carrying out double-acid catalysis on the combustion process of high polymers such as a base material;

3) the zirconium phosphate is stripped by using TBA, so that the interlayer hydroxyl of the TBA can be exposed, more active sites are available, and the grafting rate of the phenylboronic acid modified silane coupling agent is improved;

4) the zirconium phosphate is chemically modified by sequentially utilizing an aminosilane coupling agent and 4-chlorobenzeneboronic acid, and the introduction of an organic functional group can improve the compatibility of the flame retardant and the base material and is beneficial to improving the water resistance and water resistance of the base material.

Compared with the prior art, the invention has the beneficial effects that:

1) firstly, carrying out intercalation pretreatment on alpha-zirconium phosphate by using TBA, and introducing a phenylboronic acid chemically-modified silane coupling agent between layers of the zirconium phosphate to obtain a phenylboronic acid-silane graft modification-based zirconium phosphate-based flame retardant; the flame retardant performance of the flame retardant and the compatibility of the flame retardant with a high polymer material can be synchronously improved, and the related preparation method is simple, mild in reaction condition and suitable for popularization and application;

2) the flame retardant disclosed by the invention can effectively play a flame-retardant synergistic effect of phosphorus-nitrogen-boron-carbon, integrates flame retardance, smoke suppression and enhancement, is good in carbon forming effect, excellent in comprehensive performance, environment-friendly, pollution-free, good in compatibility with high polymer materials and the like, can give consideration to other properties of the materials (such as chemical stability, non-toxicity, no corrosivity on base materials and the like), and is wide in applicability.

Drawings

FIG. 1 is a graph showing the combustion back temperature curve of an intumescent fire-retardant coating prepared by using the fire retardant obtained in example 1 of the present invention

Detailed Description

In order to better understand the present invention, the following examples are further provided to illustrate the content of the present invention, but the content of the present invention is not limited to the following examples.

In the following examples, the zirconium phosphates used were all α -zirconium phosphates, and the preparation method thereof included the following steps: preparing 100mL of concentrated phosphoric acid with the molar concentration of 3mo1/L, and adding the concentrated phosphoric acid into a 250mL three-neck flask; 10.00g of zirconium oxychloride (ZrOCl) was added₂-8H₂O), heating to 95 ℃, mechanically stirring for 20min to ensure thatFully dispersing zirconium oxychloride, stopping stirring, reacting at reflux temperature for 24h, standing, naturally cooling to normal temperature, taking the milky precipitate at the lower layer, performing centrifugal treatment (10000r/min, 10min) for separation, washing the obtained solid product with a proper amount of deionized water, performing centrifugal treatment, and repeating the steps until the centrifugal clear liquid meets the pH value>And 5, drying the washed solid product in an oven at the temperature of 80 ℃ for 12 hours, and grinding to obtain the white zirconium phosphate powder.

Example 1

A preparation method of the phenylboronic acid modified zirconium phosphate based flame retardant comprises the following steps:

1) TBA stripping zirconium phosphate: in a 500ml four-mouth flask, 3.00g of zirconium phosphate and 300ml of deionized water are fully dispersed for 30min by mechanical stirring and ultrasonic action at the temperature of 5 ℃, then 10ml of TBA (tetrabutylammonium hydroxide aqueous solution, 25 wt%) is dripped into the four-mouth flask at a constant speed within 30min, ultrasonic reaction is continued for 2h after dripping, 15ml of 4mol/L concentrated phosphoric acid is dripped into the flask at a constant speed within 30min, and after the reaction is finished (2h), solid-liquid separation is carried out on the mixed solution by centrifugation to obtain semitransparent gel precipitate and washing by dioxane;

2) grafted silane coupling agent KH 550: adding the translucent gel washed in the step 1) into a four-neck flask, adding 2.21g of KH550 and 300ml of dioxane, fully dispersing the gel by mechanical stirring and ultrasonic action, then transferring the gel into an oil pan, setting the reaction temperature to 90 ℃, and mechanically stirring for 24 hours to obtain peeled ZrP;

3) grafting phenylboronic acid: adding 1.06g of triethylamine into the mixed solution obtained in the step 2) for dispersing for 10min, slowly adding 1.56g of 4-chlorobenzene boric acid (MSDS), heating to reflux for reaction for 12h, reacting at room temperature for 24h, standing after the reaction is finished, centrifuging, filtering, washing with acetone for 2-3 times, washing with absolute ethyl alcohol for 2-3 times, and finally drying in a vacuum oven to obtain the final product.

Example 2

1) TBA stripping zirconium phosphate: in a 500ml four-mouth flask, 6.00g of zirconium phosphate and 300ml of deionized water are fully dispersed for 30min by mechanical stirring and ultrasonic action at the temperature of 5 ℃, then 30ml of TBA (tetrabutylammonium hydroxide aqueous solution, 25 wt%) is dripped into the four-mouth flask at a constant speed within 30min, ultrasonic reaction is continued for 2h after dripping, 15ml of 4mol/L concentrated phosphoric acid is dripped into the flask at a constant speed within 30min, and after the reaction is finished (2h), solid-liquid separation is carried out on the mixed solution by centrifugation to obtain semitransparent gel precipitate and washing by dioxane;

2) grafted silane coupling agent KH 550: adding the translucent gel washed in the step 1) into a four-neck flask, adding 4.43g of KH550 and 300ml of dioxane, fully dispersing the gel by mechanical stirring and ultrasonic action, then transferring the gel into an oil pan, setting the reaction temperature to 90 ℃, and mechanically stirring for 24 hours to obtain peeled ZrP;

3) grafting phenylboronic acid: adding 1.06g of triethylamine into the mixed solution obtained in the step 2), dispersing for 10min, slowly adding 6.24g of 4-chlorobenzeneboronic acid (MSDS) into the device, heating to reflux and react for 12h, reacting at room temperature for 24h, standing after the reaction is finished, centrifuging, filtering, washing with acetone for 2-3 times, washing with absolute ethyl alcohol for 2-3 times, and finally drying in a vacuum oven to obtain the final product.

Example 3

1) TBAH exfoliation zirconium phosphate: in a 500ml four-mouth flask, 1.00g of zirconium phosphate and 300ml of deionized water are fully dispersed for 30min by mechanical stirring and ultrasonic action at the temperature of 5 ℃, then 30ml of TBA (tetrabutylammonium hydroxide aqueous solution, 25 wt%) is dripped into the four-mouth flask at a constant speed within 30min, ultrasonic reaction is continued for 2h after dripping, 15ml of 4mol/L concentrated phosphoric acid is dripped into the flask at a constant speed within 30min, and after the reaction is finished (2h), solid-liquid separation is carried out on the mixed solution by centrifugation to obtain semitransparent gel precipitate and washing by dioxane;

2) grafted silane coupling agent KH 550: adding the translucent gel washed in the step 1) into a four-neck flask, adding 0.74g of KH550 and 300ml of dioxane, fully dispersing the gel by mechanical stirring and ultrasonic action, then transferring the gel into an oil pan, setting the reaction temperature to 90 ℃, and mechanically stirring for 24 hours to obtain peeled ZrP;

3) grafting phenylboronic acid: adding 0.18g of triethylamine into the mixed solution obtained in the step 2), dispersing for 10min, slowly adding 1.04g of 4-chlorobenzene boric acid (MSDS) into the device, heating to perform reflux reaction for 12h, reacting at room temperature for 24h, standing after the reaction is finished, centrifuging, filtering, washing with acetone for 2-3 times, washing with absolute ethyl alcohol for 2-3 times, and finally drying in a vacuum oven to obtain a final product.

Application example 1

The flame retardant obtained in the embodiment 1 is applied to the preparation of the acrylate-based intumescent fire retardant coating, and the specific steps comprise:

1) weighing the raw materials according to the mixture ratio, wherein the components and the mass percentage thereof comprise: 20% of acrylate emulsion, 36% of ammonium polyphosphate, 12% of pentaerythritol, 12% of melamine, 3% of titanium dioxide, 0.5% of hydroxyethyl cellulose, 0.5% of dispersant, 0.5% of defoamer, 0.5% of n-octanol, 10% of water and 5% of flame retardant based on grafted phenylboronic acid silane intercalation modified zirconium phosphate;

2) grinding the weighed ammonium polyphosphate, pentaerythritol, melamine, titanium dioxide and hydroxyethyl cellulose into powder, and then adding water to fully grind and uniformly mix; adding the defoaming agent and the dispersing agent, and continuously and fully grinding;

3) and finally, adding a flame retardant based on grafted phenylboronic acid silane intercalation modified zirconium phosphate, fully grinding the acrylate emulsion and n-octanol, and uniformly mixing to obtain the fireproof coating.

Application example 2

The preparation method of the fireproof coating in application example 2 is substantially the same as that in application example 1, and is characterized in that the fireproof coating comprises the following components in percentage by mass: 20% of acrylate emulsion, 36% of ammonium polyphosphate, 12% of pentaerythritol, 12% of melamine, 3% of titanium dioxide, 0.5% of hydroxyethyl cellulose, 0.5% of dispersant, 0.5% of defoamer, 0.5% of n-octanol, 10% of water and 3% of flame retardant based on grafted phenylboronic acid silane intercalation modified zirconium phosphate.

Application example 2

The preparation method of the fireproof coating in application example 2 is substantially the same as that in application example 1, except that the fireproof coating comprises 20 mass percent of acrylate emulsion, 36 mass percent of ammonium polyphosphate, 12 mass percent of pentaerythritol, 12 mass percent of melamine, 3 mass percent of titanium dioxide, 0.5 mass percent of hydroxyethyl cellulose, 0.5 mass percent of dispersing agent, 0.5 mass percent of defoaming agent, 0.5 mass percent of n-octyl alcohol, 10 mass percent of water and 2 mass percent of flame retardant based on grafted phenylboronic acid silane intercalation modified zirconium phosphate.

Comparative example 1

The preparation method of the fireproof coating in the comparative example 1 is substantially the same as that in the application example 1, except that the fireproof coating comprises the following components in percentage by mass: 20% of acrylate emulsion, 36% of ammonium polyphosphate, 12% of pentaerythritol, 12% of melamine, 3% of titanium dioxide, 0.5% of hydroxyethyl cellulose, 0.5% of dispersant, 0.5% of defoamer, 0.5% of n-octanol and 15% of water.

Comparative example 2

The preparation method of the fireproof coating in the comparative example 2 is substantially the same as that in the application example 1, except that the fireproof coating comprises the following components in percentage by mass: 20% of acrylate emulsion, 36% of ammonium polyphosphate, 12% of pentaerythritol, 12% of melamine, 3% of titanium dioxide, 0.5% of hydroxyethyl cellulose, 0.5% of dispersant, 0.5% of defoamer, 0.5% of n-octanol, 10% of water and 5% of zirconium phosphate.

Comparative example 3

The preparation method of the fireproof coating in the comparative example 3 is substantially the same as that in the application example 1, except that the fireproof coating comprises the following components in percentage by mass: 20% of acrylate emulsion, 36% of ammonium polyphosphate, 12% of pentaerythritol, 12% of melamine, 3% of titanium dioxide, 0.5% of hydroxyethyl cellulose, 0.5% of dispersant, 0.5% of defoamer, 0.5% of n-octanol, 10% of water and 5% of 4-chlorobenzene boric acid (MSDS).

Comparative example 4

The preparation method of the fireproof coating of comparative example 4 is substantially the same as that of application example 1, except that the components and the mass percentages thereof are as follows: 20% of acrylate emulsion, 36% of ammonium polyphosphate, 12% of pentaerythritol, 12% of melamine, 3% of titanium dioxide, 0.5% of hydroxyethyl cellulose, 0.5% of dispersant, 0.5% of defoamer, 0.5% of n-octanol, 10% of water, and 5% by weight of a mixture of zirconium phosphate and 4-chlorobenzene boric acid (MSDS) (3% by weight of zirconium phosphate, 2% by weight of 4-chlorobenzene boric acid (MSDS)).

The intumescent fire-retardant coatings obtained in application examples 1-3 and comparative examples 1-4 were respectively subjected to fire resistance tests, and the results are shown in table 1.

TABLE 1 relevant Performance test of the intumescent coatings obtained in application examples 1-3 and comparative examples 1-4

The combustion back temperature curve chart of the intumescent fire-retardant coating obtained in application example 1, comparative example 1 and comparative example 2 is shown in figure 1, and the result shows that the coating prepared by using the flame retardant obtained in the invention can exert excellent flame-retardant effect.

The above results show that: the flame retardant disclosed by the invention has the advantages of higher flame retardant efficiency, environmental friendliness, no pollution, good compatibility with resin base materials and the like, and capability of effectively considering other properties of the materials.

The above description is only a preferred embodiment of the present invention, and it should be noted that those skilled in the art can make various modifications and changes without departing from the inventive concept of the present invention, and these modifications and changes are within the protection scope of the present invention.

Claims

1. The preparation method of the phenylboronic acid grafted modified zirconium phosphate-based flame retardant is characterized by comprising the following steps of:

1) dispersing zirconium phosphate in water to prepare zirconium phosphate suspension, dropwise adding tetrabutyl ammonium hydroxide into the zirconium phosphate suspension at a constant speed, stirring uniformly, and then carrying out ultrasonic treatment to obtain tetrabutyl ammonium hydroxide pre-intercalation zirconium phosphate suspension; then dropwise adding concentrated phosphoric acid into the solution, reacting to obtain semitransparent gel precipitate, and washing with a solvent;

3) and adding triethylamine for dispersion treatment, slowly adding 4-chlorobenzene boric acid, reacting, standing, centrifuging, filtering, washing and drying to obtain the phenylboronic acid modified zirconium phosphate-based flame retardant.

2. The production method according to claim 1, wherein the silane coupling agent is a silane coupling agent having an amino group.

3. The preparation method according to claim 1, wherein the solvent is one or more of absolute ethyl alcohol, dioxane, tetrahydrofuran, absolute methanol and chloroform.

4. The preparation method according to claim 1, wherein the ultrasonic treatment temperature is 0-20 ℃ and the time is 0.5-3 h.

5. The preparation method according to claim 1, wherein the reaction time in step 1) is 1-3 hours.

6. The preparation method according to claim 1, wherein the heating reaction temperature in the step 2) is 60-150 ℃ and the time is 16-24 h.

7. The method according to claim 1, wherein the reaction conditions in step 3) include: heating and refluxing for 6-18 h, and reacting at room temperature for 12-36 h.

8. The preparation method according to claim 1, wherein the molar ratio of zirconium phosphate to tetrabutylammonium hydroxide is 100:1 to 1: 50; the molar ratio of the zirconium phosphate to the silane coupling agent is 1: 3-3: 1; the molar ratio of the zirconium phosphate to the 4-chlorobenzene boric acid is 2: 1-1: 20; the molar ratio of the zirconium phosphate to the triethylamine is 1 (0.5-2).

9. The method according to claim 1, wherein the dispersion treatment time in the step 3) is 8 to 10 min.

10. The phenylboronic acid-modified zirconium phosphate-based flame retardant prepared by the preparation method of any one of claims 1 to 9.