Flame-retardant polystyrene particles and preparation method thereof
By introducing 4-aminobenzothiophene@PDA@MDH flame retardant and styrene-silane-cyanobenzic acid copolymer into polystyrene particles, a dense char layer is formed and compatibility is improved, solving the problems of insufficient flame retardant performance and impact strength of polystyrene particles, and achieving high-efficiency flame retardancy and improved mechanical properties.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-17
- Publication Date
- 2026-04-07
AI Technical Summary
The poor flame retardancy and impact strength of polystyrene particles limit their application range.
4-Aminobenzothiophene@PDA@MDH is used as a flame retardant, and through multi-layer modification and multi-element synergistic effect, combined with styrene-silane-cyanophenylboronic acid copolymer and other additives, a dense char layer is formed to improve flame retardancy and mechanical properties.
This approach achieves a balance between high flame retardancy, good mechanical properties, and stable processing performance of polystyrene particles, improving the flame retardancy efficiency and mechanical strength of the material while also enhancing compatibility and dispersibility.
Smart Images
Figure SMS_1
Abstract
Description
Technical Field
[0001] This invention relates to the field of polymer materials, and in particular to a flame-retardant polystyrene particle and its preparation method. Background Technology
[0002] Polystyrene is a polymer formed by the free radical addition polymerization of polystyrene monomers. It is a lightweight granular material with low apparent density, light weight, low thermal conductivity, low water absorption, easy processing, and low price. Furthermore, it possesses advantages such as corrosion resistance, water resistance, good electrical insulation, and ease of coloring. Due to its excellent melt thermal stability and flowability, it is easy to process and mold, especially injection molding, making it suitable for production and application. It has been widely used in household appliances, instruments, electronic products, automotive interior parts, and packaging materials. However, the poor flame retardancy and impact strength of polystyrene granules significantly limit its applications. Summary of the Invention
[0003] This invention provides flame-retardant polystyrene particles and their preparation method, which can solve the problems of poor flame-retardant performance and impact strength of polystyrene particles in the prior art.
[0004] The objective of this invention can be achieved through the following technical solutions: In a first aspect, the present invention provides flame-retardant polystyrene particles, comprising the following raw materials in parts by weight: 80-100 parts polystyrene, 8-14 parts flame retardant, 4-8 parts acrylonitrile-styrene-butadiene copolymer, 1-3 parts styrene-silane-cyanobenzyl boric acid copolymer, 8-12 parts silica, 0.4-2 parts antioxidant, and 0.4-0.8 parts lubricant; The flame retardant is 4-aminobenzothiophene@PDA@MDH.
[0005] Furthermore, the method for preparing the flame retardant is as follows: S1. Dissolve DA in Tris buffer, add MDH, and stir the reaction at room temperature for 6-8 hours to obtain PDA@MDH; S2. PDA@MDH was added to anhydrous ethanol and ultrasonically dispersed to obtain a PDA@MDH dispersion. 4-Aminobenzothiophene was dissolved in anhydrous ethanol, stirred, and then added to the PDA@MDH dispersion. Triethylamine was added, and the mixture was heated to 60°C and reacted for 16-18 hours. After centrifugation, washing, and drying, the flame retardant was obtained.
[0006] Further, in step S1, the ratio of DA, Tris buffer, and MDH is 1-1.4g: 100-200mL: 1g.
[0007] Furthermore, in step S1, the particle size of the MDH is 30–50 μm.
[0008] Further, in step S2, the ratio of PDA@MDH to anhydrous ethanol in the PDA@MDH dispersion is 0.3g:50mL; the ratio of PDA@MDH dispersion, 4-aminobenzothiophene, anhydrous ethanol, and triethylamine is 50mL:0.2-0.3g:50-60mL:1mL.
[0009] Furthermore, the preparation method of the styrene-silane-cyanophenylboronic acid copolymer is as follows: Styrene, vinyl-terminated dimethyl polysiloxane, 3-(E-2-cyanovinyl)phenylboronic acid, and azobisisobutyronitrile were added to DMF. The mixed solution was then added to a high-pressure reactor, purged with nitrogen for 10 minutes, sealed, and allowed to react. After the reaction was completed, the reactor was cooled, washed, and dried to constant weight to obtain a styrene-silane-cyanophenylboronic acid copolymer.
[0010] Further, the ratio of styrene, vinyl-terminated dimethyl polysiloxane, 3-(E-2-cyanovinyl)phenylboronic acid, azobisisobutyronitrile, and DMF is 8g:2g:1-1.5g:0.07-0.08g:40-50mL.
[0011] Furthermore, the reaction temperature is 100–120°C, and the reaction time is 4–6 hours.
[0012] Furthermore, the antioxidant is any one or more of antioxidant 1076 and antioxidant 1010.
[0013] Furthermore, the lubricant is any one or more of amide wax and zinc stearate.
[0014] Secondly, the present invention provides a method for preparing flame-retardant polystyrene particles, comprising the following steps: Polystyrene, flame retardant, acrylonitrile-styrene-butadiene copolymer, styrene-silane-cyanobenzyl boric acid copolymer, silica, antioxidant, and lubricant are mixed and extruded to granulate, thus obtaining flame-retardant polystyrene granules.
[0015] The beneficial effects of this invention are: 1. This invention achieves a balance between "highly efficient flame retardancy, good mechanical properties, and stable processing and performance" in flame-retardant polystyrene particles through the synergistic proportions and functional complementarity of various raw materials. The beneficial effects of each raw material and its corresponding weight parts are as follows: 80-100 parts of polystyrene serve as the matrix resin, ensuring the basic formability and performance of the particles; 8-14 parts of 4-aminobenzothiophene@PDA@MDH flame retardant, through the synergistic effect of "magnesium-nitrogen-sulfur" multi-element, form a dense char layer and inhibit smoke release during combustion, achieving highly efficient flame retardancy and good compatibility with the matrix; 4-8 parts of acrylonitrile-styrene-butadiene copolymer (ABS) utilize the elastic properties of the butadiene segment to compensate for the difference between the flame retardant and the silica filler. The mechanical embrittlement of the particles is reduced, thus improving their impact strength and toughness. 1-3 parts of styrene-silane-cyanobenzeneboronic acid copolymer, as a functional compatibilizer, can enhance the compatibility between matrices, solve the problem of inorganic filler agglomeration, and contains boron, which can synergistically improve the flame retardant effect of the material. 8-12 parts of silica can enhance the rigidity and heat resistance of the particles, and at the same time, synergistically improve the density of the carbon layer with the flame retardant. 0.4-2 parts of antioxidant inhibit thermal oxidative degradation during processing and use, extending the service life of the particles. 0.4-0.8 parts of lubricant optimize the processing fluidity and avoid sticking and surface defects during molding. The scientifically matched proportions of each raw material ultimately yield flame-retardant polystyrene particles with excellent comprehensive performance.
[0016] 2. This invention selects 4-aminobenzothiophene@PDA@MDH as a flame retardant, achieving multiple benefits through "multi-layer modification + multi-element synergy": the PDA coating layer inhibits MDH agglomeration through steric hindrance, its high adhesion strengthens the interfacial bonding with the matrix, and PDA itself also has flame-retardant properties; the hydrophobic fused-ring structure of 4-aminobenzothiophene further improves its compatibility with polystyrene, avoiding the attenuation of flame-retardant performance caused by filler agglomeration. Simultaneously, the nitrogen and sulfur elements it contains form a "magnesium-nitrogen-sulfur" multi-element synergistic system with the magnesium element in MDH, synergistically catalyzing the formation of a dense char layer during combustion, effectively blocking heat and oxygen transfer, and significantly improving flame-retardant efficiency. Furthermore, this modification effectively improves stress transmission and reduces stress concentration points by inhibiting filler agglomeration and enhancing interfacial bonding, thereby improving the mechanical properties of the composite material.
[0017] 3. This invention also incorporates a styrene-silane-cyanobenzic acid copolymer into the raw materials. This copolymer contains boron, which can synergistically retard flame with the main flame retardant. The chemical structure of the styrene main chain is identical to that of the polystyrene matrix, exhibiting excellent compatibility. This allows the entire copolymer to be uniformly dispersed in the matrix. The ultra-flexible dimethyl polysiloxane (PDMS) segments effectively passivate cracks and absorb impact energy by forming microphase-separated elastic microdomains, thereby significantly improving the impact toughness of the composite material. Simultaneously, the cyano and phenylboronic acid groups on the side chains can interact with acrylonitrile-styrene-butadiene copolymer, silica, and other raw materials through hydrogen bonding and other interactions. This not only improves the dispersibility of the filler and prevents agglomeration but also promotes the synergistic flame-retardant effect of elements such as boron, nitrogen, sulfur, and magnesium during combustion, catalyzing the formation of a dense and stable char layer. Ultimately, this achieves synergistic optimization of the material's flame retardancy, mechanical strength, and processing stability at low addition levels. Detailed Implementation
[0018] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below.
[0019] In a first aspect, the present invention provides flame-retardant polystyrene particles, comprising the following raw materials in parts by weight: 80-100 parts polystyrene, 8-14 parts flame retardant, 4-8 parts acrylonitrile-styrene-butadiene copolymer, 1-3 parts styrene-silane-cyanobenzyl boric acid copolymer, 8-12 parts silica, 0.4-2 parts antioxidant, and 0.4-0.8 parts lubricant; The flame retardant is 4-aminobenzothiophene@PDA@MDH.
[0020] 80-100 parts of polystyrene are used as the matrix resin to ensure the basic formability and performance of the granules; 8-14 parts of 4-aminobenzothiophene@PDA@MDH flame retardant, through the synergistic effect of magnesium-nitrogen-sulfur multi-element, form a dense char layer and suppress smoke release during combustion, achieving high-efficiency flame retardancy and good compatibility with the matrix; 4-8 parts of acrylonitrile-styrene-butadiene copolymer (ABS) utilize the elastic properties of the butadiene segment to compensate for the mechanical embrittlement caused by the flame retardant and silica filler, improving the impact strength and toughness of the granules; 1-3 parts of styrene-silane-cyanobenzeneboronic acid copolymer As a functional compatibilizer, the material can enhance the compatibility between matrices, solve the problem of inorganic filler agglomeration, and contains boron, which can synergistically improve the flame retardant effect of the material; 8-12 parts of silica can enhance the rigidity and heat resistance of the particles, and at the same time, synergistically improve the density of the carbon layer with the flame retardant; 0.4-2 parts of antioxidant inhibit thermal oxidative degradation during processing and use, and extend the service life of the particles; 0.4-0.8 parts of lubricant optimize the processing fluidity and avoid sticking and surface defects during molding. The scientific and appropriate ratio of each raw material results in flame-retardant polystyrene particles with excellent comprehensive performance.
[0021] In some embodiments, the flame retardant is prepared by: S1. Dissolve DA in Tris buffer, add MDH, and stir the reaction at room temperature for 6-8 hours to obtain PDA@MDH; MDH is a commonly used flame retardant, but it is prone to aggregation and has poor compatibility with polystyrene, which affects its flame retardant performance. Therefore, this invention improves upon it. Tris buffer provides an alkaline environment to activate the self-polymerization of dopamine (DA) on the surface of magnesium hydroxide (MDH), resulting in PDA@MDH. The polydopamine (PDA) encapsulation achieves dual optimization through interface modification: on the one hand, PDA forms a uniformly cross-linked organic coating layer on the MDH surface, generating a steric hindrance effect that hinders the aggregation of MDH particles; on the other hand, PDA has a large number of phenolic hydroxyl and amino groups, exhibiting strong adhesion, which allows MDH to be more uniformly dispersed in the raw material, contributing to the performance of flame retardant properties.
[0022] S2. PDA@MDH was added to anhydrous ethanol and ultrasonically dispersed to obtain a PDA@MDH dispersion. 4-Aminobenzothiophene was dissolved in anhydrous ethanol, stirred, and then added to the PDA@MDH dispersion. Triethylamine was added, and the mixture was heated to 60°C and reacted for 16-18 hours. After centrifugation, washing, and drying, the flame retardant was obtained.
[0023] Polydopamine and polystyrene do not have perfectly matched polarities. To further improve compatibility, this invention uses triethylamine as an alkaline catalyst to activate the nucleophilicity of the amino group in 4-aminobenzothiophene, causing the amino group to undergo a Michael addition reaction with the catechol groups in the polydopamine layer on the PDA@MDH surface. 4-aminobenzothiophene is then stably grafted onto the PDA@MDH surface via covalent bonds. The nitrogen and sulfur elements in the grafted molecule, together with the magnesium element in magnesium hydroxide (MDH), form a "magnesium-nitrogen-sulfur" multi-element synergistic flame retardant system. Furthermore, the hydrophobic fused ring structure of 4-aminobenzothiophene can improve the compatibility between the flame retardant and the polystyrene matrix. After centrifugation and washing to remove unreacted monomers and triethylamine, and drying, a flame retardant with both high flame retardant performance and good dispersibility is obtained.
[0024] In some embodiments, in step S1, the ratio of DA, Tris buffer, and MDH is 1–1.4 g: 100–200 mL: 1 g. This ensures that DA fully self-polymerizes in an alkaline environment, uniformly coating MDH, avoiding both waste due to excessive DA and insufficient dosage affecting the coating effect, thus guaranteeing the dispersibility and interfacial binding ability of PDA@MDH.
[0025] In some embodiments, in step S1, the particle size of the MDH is 30–50 μm. This particle size range can balance the flame retardant efficiency and dispersibility of MDH, avoiding both excessively small particle size leading to agglomeration and excessively large particle size leading to poor interfacial bonding with the matrix, thus helping to improve the flame retardancy and mechanical properties of the composite material.
[0026] In some embodiments, in step S2, the ratio of PDA@MDH to anhydrous ethanol in the PDA@MDH dispersion is 0.3g:50mL; the ratio of PDA@MDH dispersion, 4-aminobenzothiophene, anhydrous ethanol, and triethylamine is 50mL:0.2-0.3g:50-60mL:1mL. Preparing the PDA@MDH dispersion according to specific ratios and reacting it with other raw materials ensures that 4-aminobenzothiophene is fully grafted onto the PDA@MDH surface, while avoiding waste due to excessive raw materials or affecting the grafting effect due to insufficient materials. This enhances the compatibility between the flame retardant and the matrix, as well as the synergistic flame retardant effect of multiple elements.
[0027] In some embodiments, the preparation method of the styrene-silane-cyanophenylboronic acid copolymer is as follows: Styrene, vinyl-terminated dimethyl polysiloxane, 3-(E-2-cyanovinyl)phenylboronic acid, and azobisisobutyronitrile were added to DMF. The mixed solution was then added to a high-pressure reactor, purged with nitrogen for 10 minutes, sealed, and allowed to react. After the reaction was completed, the reactor was cooled, washed, and dried to constant weight to obtain a styrene-silane-cyanophenylboronic acid copolymer.
[0028] In the above steps, azobisisobutyronitrile (AIBN) decomposes upon heating to generate free radicals, which initiate homopolymerization and crosspolymerization of the carbon-carbon double bonds in styrene, vinyl-terminated dimethyl polysiloxane, and 3-(E-2-cyanovinyl)phenylboronic acid molecules. Through free radical chain growth, a terpolymer containing benzene rings, siloxane groups, cyano groups, and phenylboronic acid groups is formed. DMF acts as a polar solvent to ensure uniform dissolution of each monomer. Nitrogen gas is introduced to remove oxygen from the system to prevent free radical quenching and ensure the continuous polymerization reaction. After the reaction is completed, unreacted monomers, initiator residues, and solvents are removed by washing and drying, finally yielding a styrene-silane-cyanophenylboronic acid copolymer with a uniform structure. The styrene-silane-cyanoboronic acid copolymer contains boron, which can synergistically retard flame with the main flame retardant. The chemical structure of the styrene main chain is exactly the same as that of the polystyrene matrix, with excellent compatibility, which allows the entire copolymer to be uniformly dispersed in the matrix. The ultra-flexible dimethyl polysiloxane (PDMS) segments effectively passivate cracks and absorb impact energy by forming microphase-separated elastic microdomains, thereby significantly improving the impact toughness of the composite material. At the same time, the cyano and phenylboronic acid groups of the side chains can combine with raw materials such as acrylonitrile-styrene-butadiene copolymer and silica through hydrogen bonding and other interactions. This not only improves the dispersibility of the filler and prevents agglomeration, but also promotes the synergistic flame retardant effect of elements such as boron, nitrogen, sulfur, and magnesium during combustion, catalyzing the formation of a dense and stable char layer. Ultimately, the flame retardancy, mechanical strength, and processing stability of the material are synergistically optimized with low addition levels.
[0029] In some embodiments, the ratio of styrene, vinyl-terminated dimethyl polysiloxane, 3-(E-2-cyanovinyl)phenylboronic acid, azobisisobutyronitrile, and DMF is 8g:2g:1-1.5g:0.07-0.08g:40-50mL. The specific ratio of styrene and vinyl-terminated dimethyl polysiloxane ensures sufficient copolymerization of each monomer, guaranteeing both the toughening effect of the silane segments and the synergistic flame-retardant effect of the boric acid groups in the copolymer. It also avoids excessive waste of raw materials or insufficient amounts affecting the copolymer's performance, thus promoting uniform dispersion and functionality.
[0030] In some embodiments, the reaction temperature is 100–120°C, and the reaction time is 4–6 hours. This ensures the initiator activity and the copolymerization reaction proceeds fully while avoiding excessively high temperatures that could lead to raw material decomposition or excessively long reaction times that could reduce production efficiency, thus guaranteeing the uniformity of the copolymer structure.
[0031] In some embodiments, the antioxidant is any one or more of antioxidant 1076 and antioxidant 1010. It can effectively inhibit the oxidative degradation of polystyrene particles during processing and use, delay material aging, extend its service life, and maintain stable mechanical and flame-retardant properties.
[0032] In some embodiments, the lubricant is any one or more of amide wax and zinc stearate. It can reduce the frictional resistance of the raw material during the extrusion granulation process, improve processing fluidity, avoid equipment wear, and ensure uniform particle quality.
[0033] Secondly, the present invention provides a method for preparing flame-retardant polystyrene particles, comprising the following steps: Polystyrene, flame retardant, acrylonitrile-styrene-butadiene copolymer, styrene-silane-cyanobenzyl boric acid copolymer, silica, antioxidant, and lubricant are mixed and extruded to granulate, thus obtaining flame-retardant polystyrene granules.
[0034] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.
[0035] Preparation Example 1
[0036] Preparation Example 1-1
[0037] The preparation method of flame retardant is as follows: S1. Dissolve 1g of DA in 100mL of Tris buffer, add 1g of MDH (the particle size of MDH is 30μm), stir the reaction at room temperature for 6h to obtain PDA@MDH; S2. Add 0.3g PDA@MDH to 50mL of anhydrous ethanol and disperse by ultrasonication to obtain PDA@MDH dispersion; dissolve 0.2g 4-aminobenzothiophene in 50mL of anhydrous ethanol, stir, and add to 50mL of PDA@MDH dispersion, add 1mL of triethylamine, heat to 60℃ and react for 16h, then centrifuge, wash and dry to obtain flame retardant.
[0038] Preparation Examples 1-2
[0039] The preparation method of flame retardant is as follows: S1. Dissolve 1.25g DA in 150mL Tris buffer, add 1g MDH (MDH particle size is 40μm), stir and react at room temperature for 7h to obtain PDA@MDH; S2. Add 0.3g PDA@MDH to 50mL of anhydrous ethanol and disperse by ultrasonication to obtain PDA@MDH dispersion; dissolve 0.25g 4-aminobenzothiophene in 55mL of anhydrous ethanol, stir, add to 50mL of PDA@MDH dispersion, add 1mL of triethylamine, heat to 60℃ and react for 17h, then centrifuge, wash and dry to obtain flame retardant.
[0040] Preparation Examples 1-3
[0041] The preparation method of flame retardant is as follows: S1. Dissolve 1.4g DA in 200mL Tris buffer, add 1g MDH (MDH with a particle size of 50μm), stir and react at room temperature for 8h to obtain PDA@MDH; S2. Add 0.3g PDA@MDH to 50mL of anhydrous ethanol and disperse by ultrasonication to obtain PDA@MDH dispersion; dissolve 0.3g 4-aminobenzothiophene in 60mL of anhydrous ethanol, stir, and add to 50mL of PDA@MDH dispersion, add 1mL of triethylamine, heat to 60℃ and react for 18h, then centrifuge, wash and dry to obtain flame retardant.
[0042] Compare with Example 1
[0043] Compare with Example 1-1
[0044] The only difference between this comparative example and preparation example 1-1 is that 4-aminobenzothiophene is omitted. The specific steps are as follows: 1 g of DA was dissolved in 100 mL of Tris buffer, and 1 g of MDH (with a particle size of 30 μm) was added. The mixture was stirred at room temperature for 6 h to obtain PDA@MDH.
[0045] Preparation Example 2
[0046] Preparation Example 2-1
[0047] The preparation method of styrene-silane-cyanobenzonic acid copolymer is as follows: 8g of styrene, 2g of vinyl-terminated dimethyl polysiloxane, 1g of 3-(E-2-cyanovinyl)phenylboronic acid, and 0.07g of azobisisobutyronitrile were added to 40mL of DMF. The mixed solution was then added to a high-pressure reactor, purged with nitrogen for 10min, sealed, and reacted at 100℃ for 4h. After the reaction was completed, the reactor was cooled, washed, and dried to constant weight to obtain a styrene-silane-cyanophenylboronic acid copolymer.
[0048] Preparation Example 2-2
[0049] The preparation method of styrene-silane-cyanobenzonic acid copolymer is as follows: 8g of styrene, 2g of vinyl-terminated dimethyl polysiloxane, 1.25g of 3-(E-2-cyanovinyl)phenylboronic acid, and 0.075g of azobisisobutyronitrile were added to 45mL of DMF. The mixed solution was then added to a high-pressure reactor, purged with nitrogen for 10min, sealed, and reacted at 110℃ for 5h. After the reaction was completed, the reactor was cooled, washed, and dried to constant weight to obtain a styrene-silane-cyanophenylboronic acid copolymer.
[0050] Preparation Examples 2-3
[0051] The preparation method of styrene-silane-cyanobenzonic acid copolymer is as follows: 8g of styrene, 2g of vinyl-terminated dimethyl polysiloxane, 1.5g of 3-(E-2-cyanovinyl)phenylboronic acid, and 0.08g of azobisisobutyronitrile were added to 50mL of DMF. The mixed solution was then added to a high-pressure reactor, purged with nitrogen for 10min, sealed, and reacted at 120℃ for 6h. After the reaction was completed, the reactor was cooled, washed, and dried to constant weight to obtain a styrene-silane-cyanophenylboronic acid copolymer.
[0052] Compare with Example 2
[0053] Compare with Example 2-1
[0054] The only difference between this comparative example and preparation example 2-1 is that 3-(E-2-cyanovinyl)phenylboronic acid is omitted. The specific steps are as follows: 8g of styrene, 2g of vinyl-terminated dimethyl polysiloxane, and 0.07g of azobisisobutyronitrile were added to 40mL of DMF. The mixed solution was then added to a high-pressure reactor, purged with nitrogen for 10min, sealed, and reacted at 100℃ for 4h. After the reaction was completed, the reactor was cooled, washed, and dried to constant weight to obtain a styrene-silane copolymer.
[0055] Example 1
[0056] A flame-retardant polystyrene granule comprises the following raw materials in parts by weight: 80 parts polystyrene, 8 parts flame retardant obtained in Preparation Example 1-1, 4 parts acrylonitrile-styrene-butadiene copolymer, 1 part styrene-silane-cyanophenylboronic acid copolymer of Preparation Example 2-1, 8 parts silica, 0.4 parts antioxidant 1010, and 0.4 parts zinc stearate; Its preparation method is as follows: The components in the specified weight proportions are mixed and extruded to granulate, thereby obtaining flame-retardant polystyrene granules.
[0057] Example 2
[0058] A flame-retardant polystyrene granule comprises the following raw materials in parts by weight: 90 parts polystyrene, 11 parts flame retardant obtained in Preparation Example 1-1, 6 parts acrylonitrile-styrene-butadiene copolymer, 2 parts styrene-silane-cyanophenylboronic acid copolymer of Preparation Example 2-1, 10 parts silica, 1.2 parts antioxidant 1010, and 0.6 parts zinc stearate; Its preparation method is as follows: The components in the specified weight proportions are mixed and extruded to granulate, thereby obtaining flame-retardant polystyrene granules.
[0059] Example 3
[0060] A flame-retardant polystyrene granule comprises the following raw materials in parts by weight: 100 parts polystyrene, 14 parts flame retardant obtained in Preparation Example 1-1, 8 parts acrylonitrile-styrene-butadiene copolymer, 3 parts styrene-silane-cyanophenylboronic acid copolymer of Preparation Example 2-1, 12 parts silica, 2 parts antioxidant 1010, and 0.8 parts zinc stearate; Its preparation method is as follows: The components in the specified weight proportions are mixed and extruded to granulate, thereby obtaining flame-retardant polystyrene granules.
[0061] Example 4
[0062] The only difference between this embodiment and Example 3 is that the flame retardant in Example 3 is replaced with the product obtained in Preparation Example 1-2, and the styrene-silane-cyanophenylboronic acid copolymer in Example 3 is replaced with the product obtained in Preparation Example 2-2.
[0063] Example 5
[0064] The only difference between this embodiment and Example 3 is that the flame retardant in Example 3 is replaced with the product obtained in Preparation Examples 1-3, and the styrene-silane-cyanophenylboronic acid copolymer in Example 3 is replaced with the product obtained in Preparation Examples 2-3.
[0065] Comparative Example 1
[0066] The only difference between this comparative example and Example 1 is that the flame retardant in Example 1 is replaced with the product obtained in Comparative Example 1-1.
[0067] Comparative Example 2
[0068] The only difference between this comparative example and Example 1 is that the flame retardant in Example 1 is replaced with MDH, and the particle size of MDH is 30 μm.
[0069] Comparative Example 3
[0070] The only difference between this comparative example and Example 1 is that the styrene-silane-cyanobenzic acid copolymer in Example 1 is replaced with the product obtained in Comparative Example 2-1.
[0071] Comparative Example 4
[0072] The only difference between this comparative example and Example 1 is that the styrene-silane-cyanobenzyl borate copolymer is omitted.
[0073] Comparative Example 5
[0074] The only difference between this comparative example and Example 1 is that the flame retardant in Example 1 is replaced with MDH, the particle size of which is 30 μm; and the styrene-silane-cyanobenzeneboronic acid copolymer is omitted.
[0075] According to standard GB / T 1843-2008 "Determination of Impact Strength of Plastic Cantilever Beams", polystyrene granules prepared in Examples 1-5 and Comparative Examples 1-5 were compressed into samples with a thickness of 4 mm and then subjected to notched impact strength tests. The notch type was Type A, and the notch size was r. N =0.25±0.5mm, b N =8.0±0.2mm (r) N Let b be the radius of the bottom of the gap. N (The width of the notch is the length of the notch). The oxygen index of each sample was tested according to the standard GB / T 2406.1-2008 "Determination of Combustion Behavior by Oxygen Index Method for Plastics". Each sample was tested in parallel for 3 times and the average value was taken. The results were retained to one decimal place. The test results are shown in Table 1 below.
[0076] Table 1
[0077] As can be seen from Table 1, the flame retardant and mechanical properties of the polystyrene particles in Examples 1-5 are superior to those in Comparative Examples 1-5.
[0078] The test results from Example 1 and Comparative Examples 1 and 2 show that the hydrophobic fused ring structure of 4-aminobenzothiophene further enhances its compatibility with polystyrene, avoiding the degradation of flame retardant performance caused by filler agglomeration. Simultaneously, the nitrogen and sulfur elements it contains form a "magnesium-nitrogen-sulfur" multi-element synergistic system with the magnesium element in MDH, synergistically catalyzing the formation of a dense char layer during combustion, effectively blocking heat and oxygen transfer, and significantly improving flame retardant efficiency. The PDA coating layer inhibits MDH agglomeration through steric hindrance, its high adhesion strengthens the interfacial bonding with the matrix, and PDA itself also has flame retardant properties.
[0079] The test results of Example 1 and Comparative Examples 3 and 4 show that the styrene-silane-cyanobenzic acid copolymer contains boron, which can synergistically retard flame with the main flame retardant. The chemical structure of the styrene main chain is exactly the same as that of the polystyrene matrix, with excellent compatibility, which allows the entire copolymer to be uniformly dispersed in the matrix. The ultra-flexible dimethyl polysiloxane (PDMS) segments effectively passivate cracks and absorb impact energy by forming microphase-separated elastic microdomains, thereby significantly improving the impact toughness of the composite material. At the same time, the cyano and phenylboronic acid groups of the side chains can combine with raw materials such as acrylonitrile-styrene-butadiene copolymer and silica through hydrogen bonding and other interactions. This not only improves the dispersibility of the filler and prevents agglomeration, but also promotes the synergistic flame retardant effect of elements such as boron, nitrogen, sulfur, and magnesium during combustion, catalyzing the formation of a dense and stable char layer. Ultimately, the flame retardancy, mechanical strength, and processing stability of the material are synergistically optimized at low addition levels.
[0080] The above-disclosed embodiments are merely a few specific examples of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.
Claims
1. A flame-retardant polystyrene particle, characterized in that, Including the following parts by weight of raw materials: 80-100 parts polystyrene, 8-14 parts flame retardant, 4-8 parts acrylonitrile-styrene-butadiene copolymer, 1-3 parts styrene-silane-cyanobenzyl boric acid copolymer, 8-12 parts silica, 0.4-2 parts antioxidant, and 0.4-0.8 parts lubricant; The flame retardant is 4-aminobenzothiophene@PDA@MDH.
2. The flame-retardant polystyrene particles according to claim 1, characterized in that, The method for preparing the flame retardant is as follows: S1. Dissolve DA in Tris buffer, add MDH, and stir the reaction at room temperature for 6-8 hours to obtain PDA@MDH; S2. PDA@MDH was added to anhydrous ethanol and ultrasonically dispersed to obtain a PDA@MDH dispersion. 4-Aminobenzothiophene was dissolved in anhydrous ethanol, stirred, and then added to the PDA@MDH dispersion. Triethylamine was added, and the mixture was heated to 60°C and reacted for 16-18 hours. After centrifugation, washing, and drying, the flame retardant was obtained.
3. The flame-retardant polystyrene particles according to claim 2, characterized in that, In step S1, the ratio of DA, Tris buffer, and MDH is 1-1.4g: 100-200mL: 1g.
4. The flame-retardant polystyrene particles according to claim 2, characterized in that, In step S1, the particle size of the MDH is 30–50 μm.
5. The flame-retardant polystyrene particles according to claim 2, characterized in that, In step S2, the ratio of PDA@MDH to anhydrous ethanol in the PDA@MDH dispersion is 0.3g:50mL; the ratio of PDA@MDH dispersion, 4-aminobenzothiophene, anhydrous ethanol, and triethylamine is 50mL:0.2-0.3g:50-60mL:1mL.
6. The flame-retardant polystyrene particles according to claim 1, characterized in that, The preparation method of the styrene-silane-cyanophenylboronic acid copolymer is as follows: Styrene, vinyl-terminated dimethyl polysiloxane, 3-(E-2-cyanovinyl)phenylboronic acid, and azobisisobutyronitrile were added to DMF. The mixed solution was then added to a high-pressure reactor, purged with nitrogen for 10 minutes, sealed, and allowed to react. After the reaction was completed, the reactor was cooled, washed, and dried to constant weight to obtain a styrene-silane-cyanophenylboronic acid copolymer.
7. The flame-retardant polystyrene particles according to claim 6, characterized in that, The ratio of styrene, vinyl-terminated dimethyl polysiloxane, 3-(E-2-cyanovinyl)phenylboronic acid, azobisisobutyronitrile, and DMF is 8g:2g:1-1.5g:0.07-0.08g:40-50mL.
8. The flame-retardant polystyrene particles according to claim 6, characterized in that, The reaction temperature is 100–120°C, and the reaction time is 4–6 hours.
9. The flame-retardant polystyrene particles according to claim 1, characterized in that, The antioxidant is any one or more of antioxidant 1076 and antioxidant 1010; The lubricant is any one or more of amide wax and zinc stearate.
10. A method for preparing flame-retardant polystyrene particles, used to prepare the flame-retardant polystyrene particles according to any one of claims 1-9, characterized in that, Includes the following steps: Polystyrene, flame retardant, acrylonitrile-styrene-butadiene copolymer, styrene-silane-cyanobenzyl boric acid copolymer, silica, antioxidant, and lubricant are mixed and extruded to granulate, thus obtaining flame-retardant polystyrene granules.