A porous polymer flame retardant and a preparation method and application thereof

Abstract

The application discloses a kind of porous polymer flame retardant and its preparation method and application.The porous polymer flame retardant has the structure as shown in formula (I):The porous polymer flame retardant prepared in the application is novel in structure, the phosphorus content is 35.3wt%, the nitrogen content is 15.9wt%, the boron content is 12.3wt%, the total content of flame-retardant element is as high as 63.5wt%, and the stability is high.The preparation method provided in the application is simple, low in cost, suitable for large-scale production, and the porous polymer flame retardant prepared in the application has good application prospect in water-based flame-retardant coating and flame-retardant paper.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of preparation of functional polymer and flame retardant technology, and particularly relates to a porous polymer flame retardant as well as a preparation method and application thereof, in particular to a porous polymer flame retardant with synergistic flame retardation of multiple elements as well as a preparation method and application thereof. BACKGROUND

[0002] Since the appearance of polymer materials in 1907, various polymer materials have been widely used in people's production and life, but the flammable characteristics of some polymer materials have caused great harm to people's life and property safety. In order to solve the above problems, people have developed single-component flame retardants such as bromine-based, phosphorus-based, silicon-based and boron-based flame retardants, however, with the rapid development of science and technology and the continuous enhancement of people's safety and environmental protection awareness, bromine-based flame retardants which are harmful to organisms are limited in application, and single-component flame retardants can no longer meet people's pursuit of high-performance flame retardant materials, therefore, the synergistic effect of multiple flame-retardant elements of halogen-free flame retardants emerges to make up for the shortcomings of single flame-retardant method.

[0003] In addition, the unique heterocyclic structure and high phosphorus and nitrogen content of hexachlorocyclotriphosphazene make it have excellent thermal stability and flame retardant performance, and the compound has good biocompatibility and biodegradability, which meets the increasingly stringent environmental protection requirements. The research on cyclotriphosphazene flame retardants started late, at present, cyclotriphosphazene flame retardants mainly include: alkoxyl cyclotriphosphazene, phenoxy cyclotriphosphazene, phenylamino cyclotriphosphazene and the like. Researchers have applied these cyclotriphosphazene flame retardants to many polymer materials, such as polyethylene, acrylonitrile-butadiene-styrene copolymer, epoxy resin, unsaturated polyester, polylactic acid and the like, and good flame retardant effect has been obtained. This shows that cyclotriphosphazene compounds can become a kind of efficient flame retardant. However, at present, there is no report on the synthesis of polymers from cyclotriphosphazene and boronic acid compounds. SUMMARY

[0004] The main purpose of the present application is to provide a porous polymer flame retardant as well as a preparation method and application thereof, so as to overcome the shortcomings of the prior art.

[0005] In order to achieve the above-mentioned purposes, the technical scheme adopted by the present application comprises:

[0006] The present application provides a porous polymer flame retardant, which has a structure as shown in formula (I):

[0007]

[0008] The present application also provides a preparation method of the porous polymer flame retardant, which comprises:

[0009] The nucleophilic substitution reaction of a uniform mixed reaction system containing hexachlorotriphosphazene, hydrazine, alkaline catalyst and solvent is carried out under a protective atmosphere to obtain a porous polymer flame retardant.

[0010] The embodiment of the present application also provides the porous polymer flame retardant prepared by the method, and the porous polymer flame retardant comprises 35.3wt% of phosphorus, 15.9wt% of nitrogen and 12.3wt% of boron.

[0011] The embodiment of the present application also provides the use of the porous polymer flame retardant in preparing a water-based flame retardant coating.

[0012] For example, the embodiment of the present application also provides a flame-retardant paper, which at least comprises the porous polymer flame retardant.

[0013] The present application prepares a porous polymer flame retardant which is constructed by a novel linking mode of P-O bond, and the porous polymer flame retardant is halogen-free and rich in boron, nitrogen, phosphorus and other synergistic flame-retardant elements.

[0014] Compared with the prior art, the embodiment of the present application has the beneficial effects that:

[0015] (1) The porous polymer flame retardant prepared by the present application has a novel structure, the content of phosphorus is 35.3wt%, the content of nitrogen is 15.9wt%, the content of boron is 12.3wt%, and the total content of flame-retardant elements is up to 63.5wt%, and the stability is high;

[0016] (2) The porous polymer flame retardant prepared by the present application is halogen-free, and can be used in a water-based flame retardant coating, and belongs to an environment-friendly material;

[0017] (3) The preparation method of the porous polymer flame retardant is simple, the cost is low, the yield is 80% to 85%, and the method is suitable for large-scale production and has a good application and development prospect. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments described in the present application, and other drawings can be obtained by those skilled in the art without any creative effort.

[0019] Figure 1 is the infrared spectrum of hexachlorotriphosphazene and the porous polymer flame retardant in the embodiment 1 of the present application;

[0020] Figure 2 is the nitrogen adsorption-desorption isotherm curve of the porous polymer flame retardant synthesized in the embodiment 1 of the present application;

[0021] Figure 3 is a pore size distribution curve of the porous polymer flame retardant synthesized in Example 1 of the present application;

[0022] Figure 4 is a thermogravimetric curve of the porous polymer flame retardant synthesized in Example 1 of the present application under nitrogen atmosphere;

[0023] Figure 5 is a powder X-ray diffraction pattern of the porous polymer flame retardant synthesized in Example 1 of the present application;

[0024] Figure 6 is a scanning electron microscope image of the porous polymer flame retardant synthesized in Example 1 of the present application;

[0025] Figure 7 is a burning test comparison chart of the flame-retardant paper prepared in Example 1 of the present application and paper without coating of the porous polymer flame retardant. DETAILED DESCRIPTION

[0026] In view of the defects of the prior art, the present inventors have long studied and practiced and have finally proposed the technical solution of the present application, which is mainly to prepare a porous polymer flame retardant by one-pot reaction of hexachlorotriphosphazene and hydrazine dihydrochloride. The raw materials are cheap and the synthesis method is easy to obtain, and the application range is wide, which is green and environmentally friendly and has great application potential in people's production and life.

[0027] The technical solution of the present application will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0028] One aspect of the embodiments of the present application provides a porous polymer flame retardant, which has a structure as shown in formula (I):

[0029]

[0030] In some more specific embodiments, the specific surface area of the porous polymer flame retardant is 370 m 2 / g, the pore size is 4.93 nm, and the total pore volume is 1.065 cc / g.

[0031] Another aspect of the embodiments of the present application further provides a preparation method of the porous polymer flame retardant, which comprises:

[0032] Under a protective atmosphere, a nucleophilic substitution reaction is caused to occur in a uniform mixed reaction system comprising hexachlorotriphosphazene, hydrazine dihydrochloride, an alkaline catalyst and a solvent, to prepare the porous polymer flame retardant.

[0033] The reaction route of the porous polymer flame retardant prepared by one-pot reaction using hexachlorocyclotriphosphazene and hydrazine dihydrochloride as raw materials is shown as follows:

[0034]

[0035] In some more specific embodiments, the preparation method comprises:

[0036] The uniform mixed reaction system comprising hexachlorotriphosphazene, hydrazine dihydrochloride, alkaline catalyst and solvent is allowed to react at room temperature to 120°C for 5 to 7 days under a protective atmosphere to prepare the porous polymer flame retardant.

[0037] Further, the reaction in the present application is carried out under dry and oxygen-free water conditions.

[0038] Further, the reaction system is subjected to oxygen-free treatment before the nucleophilic substitution reaction occurs.

[0039] In some more specific embodiments, the molar ratio of the hexachlorocyclotriphosphazene to the hydrazine dihydrochloride is 1:1.5 to 2.

[0040] Further, the molar ratio of the alkaline catalyst to the hexachlorocyclotriphosphazene is 6 to 8:1.

[0041] Further, the mass-to-volume ratio of the hexachlorocyclotriphosphazene to the solvent is 1:100 to 150 g / mL.

[0042] Further, the alkaline catalyst comprises any one or a combination of sodium hydroxide and potassium hydroxide, and is not limited thereto.

[0043] Further, the solvent comprises any one or a combination of N,N-dimethylformamide and N,N-dimethylacetamide, and is not limited thereto.

[0044] Further, the protective atmosphere comprises a nitrogen atmosphere or an inert gas atmosphere, and is not limited thereto.

[0045] In some more specific embodiments, the preparation method further comprises: after the completion of the nucleophilic substitution reaction, the obtained mixture is subjected to filtration, washing, purification, and drying treatment.

[0046] Further, the washing liquid used in the washing treatment comprises any one or a combination of dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, diethyl ether, 1,4-dioxane, tetrahydrofuran, or acetone, and is not limited thereto.

[0047] Furthermore, the purification process includes Soxhlet extraction purification of the washed substance using N,N-dimethylformamide as a solvent.

[0048] Furthermore, the drying process is carried out at a temperature of 40–50°C for a duration of 24–48 hours.

[0049] In some more specific embodiments, the method for preparing the porous polymer flame retardant includes:

[0050] (1) Select a reaction apparatus, then check the airtightness of the reaction apparatus, and then dry it.

[0051] (2) Add a certain proportion of hexachlorocyclotriphosphazene, diboronic acid, base and solvent to a round-bottom flask under inert gas protection, so that diboronic acid reacts with hexachlorocyclotriphosphazene in the solvent in a nucleophilic substitution reaction.

[0052] (3) After the raw materials are added, sonicate until the raw materials are completely dissolved, then keep the reaction apparatus at a constant temperature for several days, and let it cool naturally to room temperature after the reaction is over.

[0053] (4) The precipitate obtained by vacuum filtration is washed at least three times with washing solvent and dried to obtain the final product, a white powdery porous polymer flame retardant.

[0054] Another aspect of the present invention provides a porous polymer flame retardant prepared by the aforementioned method, wherein the porous polymer flame retardant comprises: 35.3 wt% phosphorus, 15.9 wt% nitrogen, and 12.3 wt% boron.

[0055] Another aspect of the present invention provides the use of the aforementioned porous polymer flame retardant in the preparation of water-based flame retardant coatings.

[0056] Furthermore, the use of the porous polymer flame retardant in the preparation of flame-retardant paper.

[0057] For example, another aspect of the present invention provides a flame-retardant paper that comprises at least the aforementioned porous polymer flame retardant.

[0058] Furthermore, the porous polymer flame retardant is applied to the paper surface by any one of coating, impregnation, or spraying.

[0059] Furthermore, the limiting oxygen index of the flame-retardant paper reaches 60-66%.

[0060] The technical solution of the present invention will be further described in detail below with reference to several preferred embodiments and accompanying drawings. This embodiment is implemented on the premise of the technical solution of the invention, and provides detailed implementation methods and specific operation processes. However, the protection scope of the present invention is not limited to the following embodiments.

[0061] Unless otherwise specified, the experimental materials used in the examples below can be purchased from conventional biochemical reagent companies.

[0062] Example 1

[0063] Under a nitrogen atmosphere, hexachlorotriphosphazene (104.3 mg, 0.3 mmol), diboronic acid (40.3 mg, 0.45 mmol), and anhydrous sodium hydroxide (79.2 mg, 1.98 mmol) were added to 10 mL of N,N-dimethylacetamide in a Shrek flask. The reactor was then placed in a Dewar flask containing liquid nitrogen for free-pump-thaw treatment. This process was repeated three times. After the reaction system was allowed to return to room temperature, it was heated to 80 °C and reacted for 5 days. After the reaction was completed, the reaction solution was centrifuged to obtain a crude product, which was then washed multiple times with solvents such as N,N-dimethylformamide and tetrahydrofuran. Finally, the product was subjected to Soxhlet extraction using N,N-dimethylformamide as the solvent. The solid obtained after Soxhlet extraction was dried under vacuum at 50 °C for 48 h to obtain a white powder porous polymer flame retardant with a yield of 85%.

[0064] The aforementioned porous polymer flame retardant is uniformly coated onto the surface of paper to obtain flame-retardant paper.

[0065] Performance characterization:

[0066] (1) The 4000cm of hexachlorotriphosphazene and the synthesized porous polymer flame retardant in this embodiment -1 Up to 450cm -1 Infrared contrast full spectrum as follows Figure 1 As shown in the figure, the infrared spectrum marker is 598.7 cm⁻¹. -1 The peak is a characteristic absorption peak of P-Cl. After the polymerization reaction, the characteristic absorption peak of P-Cl at the corresponding position disappears significantly. This phenomenon indicates that the monomer hexachlorotriphosphazene has participated in the polymerization reaction.

[0067] (2) The porous polymer flame retardant synthesized in this embodiment was subjected to specific surface area and porosity analysis using a fully automated specific surface area and porosity analyzer. The nitrogen adsorption-desorption isotherm characteristics of the porous polymer flame retardant are shown in [reference needed]. Figure 2As can be seen, nitrogen adsorption-desorption testing at 77K is a crucial method for investigating the pore structure of porous materials. Nitrogen adsorption-desorption tests were conducted on this series of materials to investigate the porosity and pore size distribution of the porous polymer flame retardant. At 77K, the nitrogen adsorption capacity increased rapidly in the low-pressure region (P / P0 < 0.1), then slowed down. However, in the high-pressure region (P / P0 > 0.9), the nitrogen adsorption capacity of the porous polymer flame retardant increased rapidly with increasing pressure. This phenomenon is consistent with the H2-type hysteresis loop, indicating that the porous polymer flame retardant synthesized in this embodiment is a mesoporous material. The pore size distribution diagram calculated using density functional theory is shown below. Figure 3 The porous polymer flame retardant shown has a pore size of 4.93 nm, and its surface area, calculated using BET, is 370 m². 2 / g;

[0068] (3) Thermogravimetric analysis was performed on the porous polymer flame retardant synthesized in this embodiment, and the results are as follows: Figure 4 As shown, the porous polymer flame retardant experiences a 20% weight loss at 800℃ under nitrogen atmosphere, indicating that the synthesized porous polymer flame retardant has good thermal stability.

[0069] (4) The porous polymer flame retardant powder synthesized in this embodiment was subjected to X-ray diffraction testing, and its XRD pattern is shown below. Figure 5 As shown, porous polymer flame retardants do not have a clear ordered molecular structure and are essentially amorphous materials.

[0070] (5) Figure 6 The image shows a scanning electron microscope image of the porous polymer flame retardant synthesized in this embodiment. It can be seen that the porous polymer flame retardant aggregates into particles and spherical structures. The particles are of uneven size and do not have an ordered structure.

[0071] (6) Figure 7 The flame-retardant paper and ordinary paper prepared for this example were subjected to a burning test in air using an alcohol lamp. The experimental results showed that the paper coated with the porous polymer flame retardant (a) was not ignited but only partially charred, and the limiting oxygen index of the flame-retardant paper was 63%. In contrast, the paper without the porous polymer flame retardant burned completely quickly (b), indicating that the porous polymer flame retardant prepared in this invention has excellent flame-retardant properties.

[0072] Example 2

[0073] Under a nitrogen atmosphere, hexachlorotriphosphazene (104.3 mg, 0.3 mmol), diboronic acid (40.3 mg, 0.45 mmol), and anhydrous sodium hydroxide (72 mg, 1.8 mmol) were added to 10 mL of N,N-dimethylformamide in a Shrek flask. The reactor was then placed in a Dewar flask containing liquid nitrogen for free-pump-thaw treatment. This process was repeated three times. After the reaction system was brought back to room temperature, the reaction was carried out at room temperature for 7 days. After the reaction was completed, the reaction solution was centrifuged to obtain a crude product, which was then washed multiple times with solvents such as N,N-dimethylformamide and tetrahydrofuran. Finally, the product was subjected to Soxhlet extraction using N,N-dimethylformamide as the solvent. The solid obtained after Soxhlet extraction was dried under vacuum at 50 °C for 48 h to obtain a white powder porous polymer flame retardant with a yield of 84%.

[0074] Example 3

[0075] Under an argon atmosphere, hexachlorotriphosphazene (104.3 mg, 0.3 mmol), diboronic acid (40.3 mg, 0.45 mmol), and anhydrous sodium hydroxide (96 mg, 2.4 mmol) were added to 10 mL of N,N-dimethylacetamide in a Shrek flask. The reactor was then placed in a Dewar flask containing liquid nitrogen for free-pump-thaw treatment. This process was repeated three times. After the reaction system was allowed to return to room temperature, it was heated to 120 °C and reacted for 5 days. After the reaction was completed, the reaction solution was centrifuged to obtain a crude product, which was then washed multiple times with solvents such as N,N-dimethylformamide, tetrahydrofuran, and acetone. Finally, the product was subjected to Soxhlet extraction using N,N-dimethylformamide as the solvent. The solid obtained after Soxhlet extraction was dried under vacuum at 50 °C for 48 h to obtain a white powder porous polymer flame retardant with a yield of 82%.

[0076] Example 4

[0077] Under a nitrogen atmosphere, hexachlorotriphosphazene (104.3 mg, 0.3 mmol), diboronic acid (40.3 mg, 0.45 mmol), and anhydrous potassium hydroxide (112 mg, 2 mmol) were added to 15 mL of N,N-dimethylacetamide in a Shrek flask. The reactor was then placed in a Dewar flask containing liquid nitrogen for free-pump-thaw treatment. This process was repeated three times. After the reaction system was allowed to return to room temperature, it was heated to 80 °C and reacted for 6 days. After the reaction was completed, the reaction solution was centrifuged to obtain a crude product, which was then washed multiple times with solvents such as N,N-dimethylformamide and tetrahydrofuran. Finally, the product was subjected to Soxhlet extraction using N,N-dimethylformamide as the solvent. The solid obtained after Soxhlet extraction was dried under vacuum at 50 °C for 48 h to obtain a white powder porous polymer flame retardant with a yield of 82%.

[0078] Example 5

[0079] Under a nitrogen atmosphere, hexachlorotriphosphazene (104.3 mg, 0.3 mmol), diboronic acid (53.8 mg, 0.6 mmol), and anhydrous potassium hydroxide (112 mg, 2 mmol) were added to 10 mL of N,N-dimethylacetamide in a Shrek flask. The reactor was then placed in a Dewar flask containing liquid nitrogen for free-pump-thaw treatment. This process was repeated three times. After the reaction system was allowed to return to room temperature, it was heated to 80 °C and reacted for 6 days. After the reaction was completed, the reaction solution was centrifuged to obtain a crude product, which was then washed multiple times with solvents such as N,N-dimethylformamide and tetrahydrofuran. Finally, the product was subjected to Soxhlet extraction using N,N-dimethylformamide as the solvent. The solid obtained after Soxhlet extraction was dried under vacuum at 50 °C for 48 h to obtain a white powder porous polymer flame retardant with a yield of 80%.

[0080] Meanwhile, the same flame-retardant effect can also be obtained when the porous polymer flame retardant prepared in Examples 2-5 is coated on paper.

[0081] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0082] All aspects, embodiments, features, and examples of this invention are to be regarded as illustrative in all respects and are not intended to limit the invention, the scope of which is defined only by the claims. Other embodiments, modifications, and uses will become apparent to those skilled in the art without departing from the spirit and scope of the invention as claimed.

[0083] The use of headings and sections in this invention is not intended to limit the invention; each section can be applied to any aspect, embodiment or feature of the invention.

[0084] Throughout this invention, wherever a composition is described as having, containing, or including specific components, or wherever a process is described as having, containing, or including specific process steps, it is contemplated that the compositions taught in this invention are also substantially composed of or comprised of the described components, and that the processes taught in this invention are also substantially composed of or comprised of the described process steps.

[0085] It should be understood that the order of the steps or the order in which specific actions are performed is not particularly important, as long as the teachings of this invention remain operable. Furthermore, two or more steps or actions can be performed simultaneously.

[0086] Although the invention has been described with reference to illustrative embodiments, those skilled in the art will understand that various other changes, omissions, and / or additions can be made without departing from the spirit and scope of the invention, and that elements of the embodiments can be substituted with substantially equivalents. Furthermore, many modifications can be made without departing from the scope of the invention to adapt particular situations or materials to the teachings of the invention. Therefore, this invention is not intended to be limited to the specific embodiments disclosed for carrying out the invention, but rather is intended to encompass all embodiments falling within the scope of the appended claims. Moreover, unless specifically stated otherwise, any use of the terms first, second, etc., does not indicate any order or importance, but is used to distinguish one element from another.

Claims

1. A porous polymer flame retardant, characterized in that, It has the structure shown in equation (I):

2. The porous polymer flame retardant according to claim 1, characterized in that: The porous polymer flame retardant has a specific surface area of ​​370 m². 2 / g, pore size is 4.93nm, and total pore volume is 1.065cc / g.

3. A method for preparing the porous polymer flame retardant according to any one of claims 1-2, characterized in that, include: Under a protective atmosphere, a homogeneous mixture of hexachlorotriphosphazene, diboronic acid, an alkaline catalyst, and a solvent is subjected to a nucleophilic substitution reaction at room temperature to 120°C for 5 to 7 days to obtain the porous polymer flame retardant. The molar ratio of hexachlorocyclotriphosphazene to diboronic acid is 1:1.5-2, the molar ratio of the alkaline catalyst to hexachlorocyclotriphosphazene is 6-8:1, and the mass-volume ratio of hexachlorocyclotriphosphazene to solvent is 1:100-1:150 g / mL.

4. The preparation method according to claim 3, characterized in that: The alkaline catalyst is selected from sodium hydroxide and / or potassium hydroxide; And / or, the solvent is selected from N,N-dimethylformamide and / or N,N-dimethylacetamide; And / or, the protective atmosphere is selected from a nitrogen atmosphere and / or an inert gas atmosphere.

5. The preparation method according to claim 3, characterized in that, Also includes: After the nucleophilic substitution reaction is completed, the resulting mixture is filtered, washed, purified, and dried. The washing solution used in the washing process is selected from any one or a combination of two or more of dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, diethyl ether, 1,4-dioxane, tetrahydrofuran, or acetone. The purification process includes Soxhlet extraction purification.

6. Use of the porous polymer flame retardant according to any one of claims 1-2 in the preparation of flame retardant paper.

7. A flame-retardant paper, characterized in that, The paper contains at least one porous polymer flame retardant as described in any one of claims 1-2; the porous polymer flame retardant is applied to the surface of the paper by any one of coating, impregnation or spraying; the limiting oxygen index of the flame-retardant paper reaches 60-66%.

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