Novel acrylonitrile copolymer flame-retardant material and preparation method thereof

Abstract

The invention discloses a novel acrylonitrile copolymer flame-retardant material and a preparation method thereof, and relates to the technical field of functionalized polyacrylonitrile. According to the invention, acrylonitrile and a specific alkenyl silicon-containing monomer are used as copolymerization components, and free radical copolymerization reaction is carried out in an initiator and organic solvent system to prepare the flame-retardant material. The selected alkenyl silicon-containing monomer has both unsaturated double bonds and silicon-containing groups, and can be efficiently copolymerized with acrylonitrile and graft the silicon-containing groups to polymer chain segments, so that the material is endowed with excellent thermal stability, flame retardance and hydrophobic property, and the defects of flammability and strong hydrophilicity of a pure acrylonitrile material are overcome. The preparation process is simple and mild, reaction conditions are easy to control, complex equipment is not needed, industrial production is facilitated, and the copolymer is balanced in comprehensive performance, can be widely applied to the fields of clothing spinning, industrial building, special equipment and the like, and has outstanding practical value and market prospect.

Description

Technical Field

[0001] This invention relates to the field of functionalized polyacrylonitrile technology, and in particular to a novel acrylonitrile copolymer flame-retardant material and its preparation method. Background Technology

[0002] Acrylonitrile (PAN) fiber is spun from polyacrylonitrile or copolymers of more than 85% acrylonitrile with other second and third monomers. In China, this fiber is commercially known as "acrylic fiber". Acrylic fiber is an important type of chemical fiber and textile raw material. It is 10% lighter than natural wool, but more than twice as strong. At the same time, acrylic fiber is not susceptible to mold or insect damage, and its resistance to sunlight is twice that of wool. Therefore, it has a wide range of applications in clothing, decoration, and industrial fields.

[0003] However, the inherent defects of PAN fiber limit its further application. Its limiting oxygen index (LOI) is only about 18%, which makes it a flammable fiber. When it burns, it not only burns quickly, but also releases toxic gases such as cyanide and ammonia, posing a serious threat to personal safety and the environment. Therefore, flame retardant modification of polyacrylonitrile has become an urgent need for the industry.

[0004] Currently, the main methods for flame-retardant modification of acrylonitrile include copolymerization flame-retardant modification and blending flame-retardant modification. Among them, blending modification involves dispersing flame retardants in the spinning solution, which is relatively simple to operate but has limited flame-retardant effect; while copolymerization modification, by copolymerizing vinyl compounds containing flame-retardant elements such as halogens and phosphorus with acrylonitrile, allows the flame-retardant components to be tightly bound to the polymer chain segments, resulting in not only better flame-retardant effect but also stronger wash-resistance, making it a more advantageous modification route.

[0005] Regarding the functionalization modification of polyacrylonitrile (PAN), Liu et al. (Polymer Degradation and Stability; 2022, Vol: 203, 110062) modified PAN fibers with hydroxylamine hydrochloride (HA) to introduce aminooxime groups (A-PAN) into the PAN fibers. Then, the A-PAN samples were immersed in a ferric chloride solution to chelate Fe. 3+FR-PAN was obtained; microcalorimetry tests showed that the peak heat release rate (PHRR) and total heat release rate (THR) of FR-PAN decreased by 72.9% and 86.9%, respectively; at the same time, the limiting oxygen index (LOI) of FR-PAN increased from 17.0% to 36.7%. Zhou et al. (Journal of Macromolecular Science Part A - Pure and Applied Chemistry; 2019, Volume: 56(12), 1097-1103) prepared halogen-free flame-retardant polyacrylonitrile (PAN) by hydrolyzing PAN nitrile groups with sodium carbonate aqueous solution / hydrogen peroxide and grafting diphenylphosphinoyl chloride; TG curves showed that at 800℃, the carbon residue of FR-PAN was 45%, which was higher than that of the original PAN (39%). The above studies focused on phosphorus-containing and iron-containing systems. At present, new acrylonitrile copolymerization technology still needs to be explored to expand its application in more severe scenarios. Summary of the Invention

[0006] The purpose of this invention is to provide a novel acrylonitrile copolymer flame retardant material and its preparation method, so as to solve the problems existing in the prior art.

[0007] To achieve the above objectives, the present invention provides the following solution: This invention provides an acrylonitrile copolymer with the structure shown in Formula I: Formula I; R1, R2, and R3 are each independently selected from... , , , , or Where n = 500 - 1500; x = 150 - 1600, y = 100 - 800.

[0008] The present invention also provides a method for preparing the above-mentioned acrylonitrile copolymer, comprising the following steps: An alkenyl silicon-containing monomer and acrylonitrile are dissolved in an organic solvent and polymerized under the action of an initiator to obtain the acrylonitrile copolymer. The structure of the alkenyl silicon-containing monomer is shown in Formula II: Formula II; R1, R2, and R3 are each independently selected from... , , , , or Where n = 500 - 1500; The alkenyl silicon-containing monomers include vinyltriethoxysilane, vinyltrimethoxysilane, vinyltri(β-methoxyethoxy)silane, dimethyl(dimethylamino)vinylsilane, or vinyl silicone oil. Specifically: When R1, R2, and R3 are all When the alkenyl silicon-containing monomer is vinyltriethoxysilane, the structural formula is: ; When R1, R2, and R3 are all When the alkenyl silicon-containing monomer is vinyltrimethoxysilane, the structural formula is: ; When R1, R2, and R3 are all When the alkenyl silicon-containing monomer is vinyltris(β-methoxyethoxy)silane, the structural formula is: ; When R1 and R2 are R3 is When the alkenyl silicon-containing monomer is dimethyl(dimethylamino)vinylsilane, the structural formula is: ; When R1 and R2 are R3 is When the alkenyl silicon-containing monomer is vinyl silicone oil, the structural formula is: , n=500-1500.

[0009] Furthermore, the polymerization reaction is carried out at a temperature of 40–80°C, for a reaction time of 6–12 h, and at a reaction pressure of 0.1 MPa.

[0010] Furthermore, the initiator includes oil-soluble initiators such as azobisisobutyronitrile, azobisisoheptanenitrile, or benzoyl peroxide.

[0011] Furthermore, the mass ratio of acrylonitrile, alkenyl silicon-containing monomer to initiator is 10-90:10-90:0.1-5.

[0012] Furthermore, in the reaction system of the polymerization reaction, the total mass concentration of the alkenyl silicon-containing monomer and acrylonitrile is 15% to 45%.

[0013] Furthermore, in the polymerization reaction system, the concentration of the initiator is 0.01 mol / L to 0.1 mol / L.

[0014] Furthermore, the organic solvent includes dimethyl sulfoxide, N,N-dimethylformamide, or dimethyl carbonate.

[0015] Furthermore, after the polymerization reaction is completed, the process also includes pouring the obtained solution into anhydrous ethanol to precipitate the product, and then drying, grinding, filtering, washing, and drying the product.

[0016] The present invention also provides the application of the above-mentioned acrylonitrile copolymer as a flame retardant material in the fields of clothing and textiles, industrial construction and special equipment; its water contact angle is 90° to 120° and its peak heat absorption temperature is 270° to 310°.

[0017] The present invention discloses the following technical effects: This invention prepares a novel copolymer flame retardant material by free radical copolymerization of acrylonitrile and a specific alkenyl silicon-containing monomer. The selected alkenyl silicon-containing monomer has both unsaturated double bonds and silicon-containing groups, and can achieve efficient copolymerization with acrylonitrile in a suitable reaction system, so that the silicon-containing groups are successfully grafted into the polymer chain segment, providing a solid structural support for the optimization of material properties.

[0018] The copolymer prepared by this invention exhibits significantly improved thermal stability. Under high-temperature conditions, the silicon-containing groups can form a stable cross-linked network, effectively inhibiting the thermal decomposition reaction of polymer molecules, thereby endowing the material with excellent flame-retardant potential and successfully overcoming the inherent flammability of pure acrylonitrile materials. At the same time, the copolymer surface exhibits good hydrophobic properties, with a significant improvement in hydrophilicity compared to pure acrylonitrile materials, further broadening the application scenarios of the material in different humidity environments.

[0019] The preparation process of this invention is simple and mild, with easily controllable reaction conditions. It requires no complex equipment or demanding operations, which is conducive to industrial-scale production. Furthermore, the material properties can be flexibly adjusted by changing the type and ratio of alkenyl silicon-containing monomers to meet the personalized needs of different application scenarios. This copolymer combines excellent flame retardancy, hydrophobicity, and thermal stability, exhibiting balanced overall performance. It successfully expands the application space of acrylonitrile-based materials in multiple fields such as clothing and textiles, industrial construction, and special equipment, possessing outstanding practical value and broad market prospects. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 The Fourier transform infrared (FTIR) spectra of the novel acrylonitrile copolymer flame-retardant materials and pure PAN in Examples 1-2 of this invention are shown below at 25°C.

[0022] Figure 2The DSC curves of the novel acrylonitrile copolymer flame retardant materials of Examples 1-3 of the present invention and pure PAN heated at 10℃ / min (nitrogen atmosphere (a) and oxygen atmosphere (b)).

[0023] Figure 3 The TG curves are for the novel acrylonitrile copolymer flame retardant materials of Examples 1-3 and pure PAN.

[0024] Figure 4 is a schematic diagram of the water contact angle of the novel acrylonitrile copolymer flame retardant material and pure PAN in Examples 1-10 of the present invention. Detailed Implementation

[0025] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0026] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included within the scope of this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0027] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0028] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0029] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0030] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0031] The preparation of the novel acrylonitrile copolymer flame-retardant material of the present invention will be further described in detail below with reference to the embodiments: The synthetic route of this invention is as follows: .

[0032] Example 1 This embodiment provides a method for preparing a novel acrylonitrile copolymer flame-retardant material, the steps of which are as follows: In a clean, dry 250 mL four-necked flask, 10 g of acrylonitrile, 3 g of vinyltriethoxysilane, and 55 g of dimethyl sulfoxide were added sequentially. After starting the stirrer, the flask was placed in a 60 °C water bath for heating. When the system temperature stabilized at 60 °C, 1.0 g of azobisisobutyronitrile (AIBN) initiator was added, and the mechanical stirring speed was adjusted to 400 rpm. The reaction was started. During the reaction, the system temperature was maintained at a constant 60 °C using the water bath system. As the reaction proceeded, the system gradually changed from colorless and transparent to orange-yellow. After stirring continuously for 8 hours, the reaction was terminated, and the reaction solution was slowly poured into excess anhydrous ethanol to precipitate the product.

[0033] The precipitated product was first dried, then ground into a fine powder in a mortar. The powder was washed twice with anhydrous ethanol, and filtered to remove residual monomers and initiators. Finally, the filter cake was placed in a vacuum oven and dried at 50°C for 48 hours to obtain 9.1 g of the polymer product. The structural formula of the obtained polymer product is as follows: , where x=430, y=130.

[0034] Inductively coupled plasma (ICP) testing revealed that the silicon (Si) content in the product was 0.2 wt%.

[0035] Example 2 This embodiment provides a method for preparing a novel acrylonitrile copolymer flame-retardant material, the steps of which are as follows: In a clean, dry 250 mL four-necked flask, 10 g of acrylonitrile, 5 g of vinyltriethoxysilane, and 55 g of dimethyl sulfoxide were added sequentially. After starting the stirrer, the flask was placed in a 60 °C water bath for heating. When the system temperature stabilized at 60 °C, 0.75 g of azobisisobutyronitrile (AIBN) initiator was added, and the mechanical stirring speed was adjusted to 400 rpm. The reaction was started. During the reaction, the system temperature was maintained at a constant 60 °C using the water bath system. As the reaction proceeded, the system gradually changed from colorless and transparent to orange-yellow. After stirring continuously for 8 hours, the reaction was terminated, and the reaction solution was slowly poured into excess anhydrous ethanol to precipitate the product.

[0036] The precipitated product was first dried, then ground into a fine powder in a mortar. The powder was washed twice with anhydrous ethanol, and filtered to remove residual monomers and initiators. Finally, the filter cake was placed in a vacuum oven and dried at 50°C for 48 hours to obtain 8.1 g of the polymer product. The structural formula of the obtained polymer product is as follows: , where x=320, y=160.

[0037] Inductively coupled plasma (ICP) testing revealed that the silicon (Si) content in the product was 1.9 wt%.

[0038] Example 3 This embodiment provides a method for preparing a novel acrylonitrile copolymer flame-retardant material, the steps of which are as follows: In a clean, dry 250 mL four-necked flask, add 10 g of acrylonitrile, 10 g of vinyltriethoxysilane, and 55 g of dimethyl sulfoxide sequentially. After starting the stirrer, place the flask in a 60 °C water bath for heating. Once the system temperature stabilizes at 60 °C, add 0.5 g of azobisisobutyronitrile (AIBN) as the initiator, and simultaneously adjust the mechanical stirring speed to 400 rpm, starting the reaction timer. During the reaction, maintain a constant system temperature of 60 °C using the water bath system. As the reaction proceeds, the system gradually changes from colorless and transparent to orange-yellow. After continuously stirring for 8 hours, terminate the reaction and slowly pour the reaction solution into excess anhydrous ethanol to precipitate the product.

[0039] The precipitated product was first dried, then ground into a fine powder in a mortar. The powder was washed twice with anhydrous ethanol, and filtered to remove residual monomers and initiators. Finally, the filter cake was placed in a vacuum oven and dried at 50°C for 48 hours to obtain 8.4 g of the polymer product. The structural formula of the obtained polymer product is as follows: , where x=190, y=190.

[0040] Inductively coupled plasma (ICP) testing revealed that the silicon (Si) content in the product was 4.8 wt%.

[0041] Example 4 This embodiment provides a method for preparing a novel acrylonitrile copolymer flame-retardant material, the steps of which are as follows: In a clean, dry 250 mL four-necked flask, add 10 g of acrylonitrile, 10 g of vinyltriethoxysilane, and 55 g of dimethyl sulfoxide sequentially. After starting the stirrer, place the flask in a 60 °C water bath for heating. Once the system temperature stabilizes at 60 °C, add 1.0 g of azobisisobutyronitrile (AIBN) as the initiator, and simultaneously adjust the mechanical stirring speed to 400 rpm, starting the reaction timer. During the reaction, maintain a constant system temperature of 60 °C using the water bath system. As the reaction proceeds, the system gradually changes from colorless and transparent to orange-yellow. After continuously stirring the reaction for 8 hours, terminate the reaction and slowly pour the reaction solution into excess anhydrous ethanol to precipitate the product.

[0042] The precipitated product was first dried, then ground into a fine powder in a mortar. The powder was washed twice with anhydrous ethanol, and filtered to remove residual monomers and initiators. Finally, the filter cake was placed in a vacuum oven and dried at 50°C for 48 hours to obtain 9.7 g of the polymerized product. The structural formula of the obtained polymerized product is as follows: Where x = 150 and y = 150; Inductively coupled plasma (ICP) testing revealed that the silicon (Si) content in the product was 4.5 wt%.

[0043] Example 5 This embodiment provides a method for preparing a novel acrylonitrile copolymer flame-retardant material, the steps of which are as follows: In a clean, dry 250 mL four-necked flask, 10 g of acrylonitrile, 15 g of vinyltriethoxysilane, and 55 g of dimethyl sulfoxide were added sequentially. After starting the stirrer, the flask was placed in a 60 °C water bath for heating. When the system temperature stabilized at 60 °C, 1.25 g of azobisisobutyronitrile (AIBN) initiator was added, and the mechanical stirring speed was adjusted to 400 rpm. The reaction was started. During the reaction, the system temperature was maintained at a constant 60 °C using the water bath system. As the reaction proceeded, the system gradually changed from colorless and transparent to orange-yellow. After stirring continuously for 8 hours, the reaction was terminated, and the reaction solution was slowly poured into excess anhydrous ethanol to precipitate the product.

[0044] The precipitated product was first dried, then ground into a fine powder in a mortar. The powder was washed twice with anhydrous ethanol, and filtered to remove residual monomers and initiators. Finally, the filter cake was placed in a vacuum oven and dried at 50°C for 48 hours to obtain 8.6 g of the polymer product. The structural formula of the obtained polymer product is as follows: Where x=140, y=120; Inductively coupled plasma (ICP) testing revealed that the silicon (Si) content in the product was 4.2 wt%.

[0045] Example 6 This embodiment provides a method for preparing a novel acrylonitrile copolymer flame-retardant material. The preparation process is the same as in Example 1, except that the monomer used is vinyltrimethoxysilane. The structural formula of the obtained polymer product is: , where x=300, y=250.

[0046] Inductively coupled plasma (ICP) testing revealed that the silicon (Si) content in the product was 3.2 wt%.

[0047] Example 7 This embodiment provides a method for preparing a novel acrylonitrile copolymer flame-retardant material. The preparation process is the same as in Example 1, except that the monomer used is vinyl silicone oil (structural formula: (n=1000).

[0048] The structural formula of the obtained polymer product is: Where x=415, y=350, n=1000; Inductively coupled plasma (ICP) testing revealed that the silicon (Si) content in the product was 2.7 wt%. Example 8 This embodiment provides a method for preparing a novel acrylonitrile copolymer flame-retardant material. The preparation process is the same as in Example 1, except that N,N-dimethylformamide is used as the solvent in the polymerization system. The structural formula of the obtained polymerization product is: Where x = 300, y = 290; Inductively coupled plasma (ICP) testing revealed that the silicon (Si) content in the product was 3.8 wt%.

[0049] Example 9 This embodiment provides a method for preparing a novel acrylonitrile copolymer flame retardant material. The preparation process is the same as in Example 3, except that the monomer used is vinyltris(β-methoxyethoxy)silane.

[0050] The structural formula of the obtained polymer product is: Where x = 400 and y = 350; Inductively coupled plasma (ICP) testing revealed that the silicon (Si) content in the product was 3.6 wt%.

[0051] Example 10 This embodiment provides a method for preparing a novel acrylonitrile copolymer flame retardant material. The preparation process is the same as in Example 3, except that the monomer used is dimethyl(dimethylamino)vinylsilane.

[0052] The structural formula of the obtained polymer product is: Where x=370 and y=320; Inductively coupled plasma (ICP) testing revealed that the silicon (Si) content in the product was 3.1 wt%.

[0053] Effect verification: Figure 1 The Fourier transform infrared (FTIR) spectra of the novel acrylonitrile copolymer flame-retardant materials of Examples 1-2 and pure PAN at 25°C are shown in the figure. As can be seen from the figure, at 790 cm⁻¹... -1 The samples in Examples 1-2 showed a characteristic C-Si absorption peak, while the pure PAN sample did not have this absorption peak; at the same time, the 960 cm⁻¹ peak was observed. -1 The samples in Examples 1-2 exhibited characteristic Si-O absorption peaks, which directly proves that vinyltriethoxysilane (VTES) has been successfully polymerized into the polymer chain segment.

[0054] Observe 2940cm -1 The methylene stretching vibration peak at [value missing] was observed, and a peak splitting phenomenon was found in the samples of Examples 1-2. This is because there are two methylene groups from different sources in the molecule (acrylonitrile and VTES, respectively), and their symmetric and asymmetric stretching vibrations are coupled, resulting in the splitting of the absorption peak, with the peak at 2940 cm⁻¹ being the most prominent. -1 Corresponding to the methylene group in acrylonitrile, 2979cm -1 Corresponding to the methylene group in VTES, this phenomenon further confirms the successful copolymerization of VTES and acrylonitrile.

[0055] Figure 2 The images show the DSC curves of the novel acrylonitrile copolymer flame-retardant materials from Examples 1-3 and pure PAN at a heating rate of 10°C / min (nitrogen atmosphere (a) and oxygen atmosphere (b)). The pure PAN sample exhibits a significant endothermic peak at 266.6°C, while the endothermic peak temperature of the example series samples is delayed by 41.4°C compared to pure PAN. The same trend is observed in the oxygen atmosphere. This is because VTES forms a Si-O-Si crosslinked network at high temperatures, which effectively hinders the cyclization and decomposition of cyano groups in the polymer molecules. The shift of the endothermic peak to the higher temperature range indicates that the thermal stability of the silicon-containing copolymer is significantly improved compared to the pure PAN homopolymer.

[0056] Figure 3The TG curves for the novel acrylonitrile copolymer flame retardant materials of Examples 1-3 and pure PAN are shown at a heating rate of 10°C / min. The thermal weight loss of PAN can be divided into three stages: trace weight loss, slow weight loss, and severe weight loss. The temperature range for trace weight loss is from 40°C to 260°C. Weight loss in this stage is mainly due to dehydrogenation, as cyclization has no effect on the weight loss of PAN. Furthermore, the weight loss rate increases with increasing VTES content. This is because the comonomer VTES undergoes Si-O crosslinking and the removal of small molecules such as ethers during this process. The slow weight loss region is between 260°C and 470°C. Significant weight loss is attributed to the degradation of low-molecular-weight substances and the release of defective structures. The severe weight loss region exceeds 470°C, where the PAN polymer experiences drastic weight loss. At the same temperature, the char residue of Example 1 is slightly higher than that of pure PAN. However, the char residue of Examples 2 and 3 is much higher than that of Example 1 and pure PAN, indicating that the addition of VTES to pure PAN significantly improves the thermal stability of PAN under high-temperature treatment.

[0057] Figure 4 shows the water contact angles of the novel acrylonitrile copolymer flame-retardant materials of Examples 1-10 and pure PAN. Under the same test conditions, the water contact angle of the sample in Example 3 reached 98°, the water contact angle of the sample in Example 4 reached 93°, and the water contact angle of the sample in Example 5 reached 91°, all of which are much higher than the 53° of the pure PAN sample and meet the hydrophobic performance judgment criteria (water contact angle ≥ 90°). Furthermore, the water contact angle of the sample increases with the increase of VTES addition, proving that the copolymer has excellent surface hydrophobic properties. The water contact angles of the other examples are all higher than those of pure PAN, and their values ​​are consistent with the silicon content in their copolymers.

[0058] Table 1 shows the LOI results for pure PAN and flame-retardant polyacrylonitrile samples. The LOI of pure PAN is 18.0%, classifying it as a flammable material without flame-retardant properties. The PAN after copolymerization with silicon-containing monomers showed a significant improvement in LOI, with Example 3 reaching 27.2%, an increase of 9.2%, indicating a marked improvement in flame-retardant performance.

[0059] Table 1. Oxygen Index of Pure PAN and Flame-Retardant PAN from the Examples The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. An acrylonitrile copolymer, characterized by, The structure is shown as formula I: Formula I; R1, R2and R3are each independently selected from , , , , or ; wherein n = 500-1500; x = 150-1600, y = 100-800.

2. The process for preparing an acrylonitrile copolymer according to claim 1, characterized by, The method comprises the following steps: The alkenyl silicon-containing monomer and acrylonitrile are dissolved in an organic solvent, and polymerization is carried out under the action of an initiator to obtain the acrylonitrile copolymer; The structure of the alkenyl silicon-containing monomer is shown as formula II: Formula II; R1, R2and R3are each independently selected from , , , , or ; wherein n = 500-1500.

3. The production method according to claim 2, characterized by, The temperature of the polymerization reaction is 40-80℃, the reaction time is 6-12h, and the reaction pressure is 0.1 MPa.

4. The production method according to claim 2, characterized by, The initiator comprises azobisisobutyronitrile, azobisisoheptyl nitrile or dibenzoyl peroxide.

5. The preparation method according to claim 2, characterized in that, The mass ratio of the acrylonitrile, alkenyl silicon-containing monomer and initiator is 10-90:10-90:0.1-5.

6. The preparation method according to claim 2, characterized in that, In the reaction system of the polymerization reaction, the total mass concentration of the alkenyl silicon-containing monomer and acrylonitrile is 15% ~ 45%.

7. The preparation method according to claim 2, characterized in that, In the reaction system of the polymerization reaction, the concentration of the initiator is 0.01 mol / L ~ 0.1 mol / L.

8. The preparation method according to claim 2, characterized in that, The organic solvent comprises dimethyl sulfoxide, N,N-dimethylformamide or dimethyl carbonate.

9. Application of the acrylonitrile copolymer of claim 1 as a flame-retardant material in the fields of clothing textiles, industrial buildings and special equipment.

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