Flame-retardant polystyrene foam material and preparation method thereof

Abstract

The invention discloses a flame-retardant polystyrene foam material and a preparation method thereof, and relates to the technical field of foam materials. According to the flame-retardant polystyrene foam material and the preparation method thereof, the borax pentahydrate, the aluminum hydroxide, the boric acid and the graphene loaded with the ionic liquid are added as fillers, so that the flame-retardant property of the polystyrene foam material is improved, and meanwhile, the good mechanical property of the polystyrene foam material is maintained. Expanded graphite and borax pentahydrate are modified by using polystyrene, so that the modified graphene and borax pentahydrate have better compatibility in a polystyrene foam material matrix, and the flame retardance and mechanical properties of the polystyrene foam material are enhanced.

Description

Technical Field

[0001] The invention relates to the technical field of foam materials, in particular to a flame retardant polystyrene foam material and a preparation method thereof. Background Art

[0002] Polystyrene foam is a lightweight porous material widely used in packaging, construction, heat insulation, thermal insulation and other fields. Its excellent lightweight, heat insulation and low cost make it widely used in various industries. However, polystyrene foam material itself is highly flammable. Once a fire occurs, it is easy to cause large-scale fire spread and release of toxic gases, posing a great threat to people's lives and property safety.

[0003] In order to improve the safety of polystyrene foam materials, developing polystyrene foam materials with good flame retardant properties has become one of the research focuses. Traditional flame retardant methods mainly improve the flame retardant properties of foam materials by adding flame retardants. These flame retardants usually contain halogen, phosphorus, nitrogen or metal compounds, which can inhibit or delay the oxidation reaction of polystyrene during combustion, thereby slowing down the spread of flames. However, existing flame retardant polystyrene foam materials often find it difficult to find an ideal balance between flame retardant effect and physical properties. The addition of many flame retardants will affect the mechanical properties, thermal stability or integrity of the foam structure, thereby affecting the actual application performance of the material.

[0004] In order to solve the above problems and improve the flame retardant performance, the present invention provides a flame retardant polystyrene foam material and a preparation method thereof. Summary of the invention

[0005] The object of the present invention is to provide a flame retardant polystyrene foam material and a preparation method thereof, so as to solve the problems raised in the prior art.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A method for preparing a flame retardant polystyrene foam material comprises the following steps:

[0008] Step 1: Take water and vinyl chloride-vinylidene chloride copolymer emulsion, mix for 15-20 minutes, and obtain premixed slurry A;

[0009] Step 2: Take latex I, latex II, carbon liquid, deionized water, modified borax pentahydrate, aluminum hydroxide, boric acid, and graphene loaded with ionic liquid to obtain a premixed slurry B, foam, mature, mix for 70-90 minutes, dry, and shape to obtain a flame-retardant polystyrene foam material.

[0010] Preferably, the premixed slurry A comprises the following components, by weight: 25-27 parts of deionized water, 75-80 parts of vinyl chloride-vinylidene chloride copolymer latex;

[0011] The premixed slurry B includes the following components, calculated by weight: 20-22 parts of latex I, 60-65 parts of latex II, 28-30 parts of carbon liquid, 5-10 parts of deionized water, 20-21 parts of modified borax pentahydrate, 10-11 parts of aluminum hydroxide, 7-8 parts of boric acid, and 1-2 parts of graphene loaded with ionic liquid.

[0012] More optimally, the latex I is a carboxylated styrene-butadiene dispersion; and the latex II is an aqueous styrene-acrylate copolymer dispersion.

[0013] More optimally, the preparation method of the graphene loaded with ionic liquid is: take polystyrene modified graphene and 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid, mix them evenly, add deionized water, ultrasonically disperse for 30-40 minutes, add phytic acid, stir evenly, add zinc chloride aqueous solution, ball mill for 42-45 hours, and dry to obtain graphene loaded with ionic liquid.

[0014] More optimally, the preparation method of the polystyrene modified graphene is: take graphene oxide and tetrahydrofuran solution, stir evenly to obtain graphene oxide solution; take polystyrene and tetrahydrofuran solution, stir evenly, add graphene oxide solution, stir for 22-24h, pour into methanol solution, stir for 20-40min, filter and dry to obtain polystyrene modified graphene.

[0015] More optimally, the preparation method of the modified borax pentahydrate is: take borax pentahydrate and tetrahydrofuran solution, stir evenly to obtain a borax pentahydrate solution; take polystyrene and tetrahydrofuran solution, stir evenly, add the borax pentahydrate solution, stir for 22-24 hours, pour into methanol solution, stir for 20-40 minutes, filter and dry to obtain modified borax pentahydrate.

[0016] More optimally, the preparation method of the polystyrene is: take styrene, polyethylene glycol-4-cyano-4-(phenylcarbonylthiothiothio) pentanoate, and azobisisobutyronitrile, stir for 10-15 minutes to obtain a mixed solution, place the mixed solution in liquid nitrogen to solidify, evacuate, thaw, heat to 75-80°C to react for 46-50 hours, and cool to obtain polystyrene.

[0017] More optimally, the preparation method of graphene oxide is: take graphite, sodium nitrate, potassium permanganate, and concentrated sulfuric acid, react at 15-17°C for 2-4h, heat to 30-35°C, stir for 50-70min, add deionized water, heat to 90-95°C, stir for 50-70min, add deionized water, add hydrogen peroxide and concentrated hydrochloric acid, react until no bubbles are generated, stir at 20-25°C for 40-50min, wash, and dry to obtain graphene oxide.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The present invention provides a flame retardant polystyrene foam material and a preparation method thereof, wherein borax pentahydrate, aluminum hydroxide, boric acid, and graphene loaded with ionic liquid are added as fillers, thereby improving the flame retardant properties of the polystyrene foam material while maintaining the good mechanical properties of the foam material.

[0020] 2. Use polystyrene to modify graphene and borax pentahydrate, so that the modified graphene and borax pentahydrate have better compatibility in the polystyrene foam material matrix, and enhance the flame retardancy and mechanical properties of the polystyrene foam material. Load 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid on graphene to improve the flame retardancy of graphene, and then add phytic acid for further modification to improve the flame retardancy of the polystyrene foam material. Finally, add zinc chloride aqueous solution to introduce metal zinc ions through chelation to promote the formation of carbon, and further improve the flame retardancy of the polystyrene foam material. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] The sources and models of the materials involved in the present invention are not particularly limited, and illustratively include: latex I: water-based latex, carboxylated styrene-butadiene dispersion, model: Styronal ND811, which can be purchased from BASF; latex II: water-based latex, water-based styrene-acrylate copolymer dispersion, model: Acronal NX 4787, which can be purchased from BASF; carbon liquid: Aquablak 770, which can be purchased from ChromaScape; graphite: model: 282863, which can be purchased from Merck; vinyl chloride-vinylidene chloride copolymer emulsion, model: Vycar 660x14, which can be purchased from Lubrizol Advanced Materials; borax pentahydrate: mesh number: 8 mesh; aluminum hydroxide: mesh number: 325 mesh; boric acid: mesh number: 80 mesh.

[0023] Embodiment 1: A method for preparing a flame retardant polystyrene foam material, comprising the following steps:

[0024] Step 1: Take water and vinyl chloride-vinylidene chloride copolymer emulsion, mix for 18 minutes, and obtain premixed slurry A;

[0025] Take latex I, latex II, carbon liquid, deionized water, modified borax pentahydrate, aluminum hydroxide, boric acid, and graphene loaded with ionic liquid to obtain a premixed slurry B, foam, mature, mix for 80 minutes, dry, and shape to obtain a flame-retardant polystyrene foam material;

[0026] The premixed slurry A comprises the following components, by weight: 26 parts of deionized water, 78 parts of vinyl chloride-vinylidene chloride copolymer latex;

[0027] The premixed slurry B includes the following components, by weight: 22 parts of latex I, 63 parts of latex II, 29 parts of carbon liquid, 8 parts of deionized water, 20.5 parts of modified borax pentahydrate, 10.5 parts of aluminum hydroxide, 7.5 parts of boric acid, and 1.5 parts of graphene loaded with ionic liquid;

[0028] The latex I is a carboxylated styrene-butadiene dispersion; the latex II is a water-based styrene-acrylate copolymer dispersion;

[0029] Step 2: Preparation of polystyrene:

[0030] Take 40 g of styrene, 80 mg of polyethylene glycol-4-cyano-4-(phenylcarbonylthiothiothio) valerate, and 64 mg of azobisisobutyronitrile, stir for 12 min to obtain a mixed solution, place the mixed solution in liquid nitrogen to solidify, evacuate, thaw, heat to 78°C, react for 48 h, and cool to obtain polystyrene;

[0031] Step 3: Preparation of polystyrene modified graphene:

[0032] Take 1g of graphite, 0.6g of sodium nitrate, 3g of potassium permanganate, and 25mL of concentrated sulfuric acid, react at 16°C for 3h, heat to 32°C, stir for 60min, add 100mL of deionized water, heat to 92°C, stir for 60min, add 80mL of deionized water, add 10mL of 30% hydrogen peroxide and concentrated hydrochloric acid, react until no bubbles are generated, stir at 22°C for 45min, wash until the pH value reaches 7, and dry to obtain graphene oxide;

[0033] Take 0.3 g of graphene oxide and 10 mL of tetrahydrofuran solution, stir evenly to obtain a graphene oxide solution; take 10 g of polystyrene and 20 mL of tetrahydrofuran solution, stir evenly, add the graphene oxide solution, stir for 23 h, pour into 80 mL of methanol solution, stir for 30 min, filter and dry to obtain polystyrene modified graphene;

[0034] Step 4: Preparation of graphene loaded with ionic liquid:

[0035] Take 3g of polystyrene modified graphene and 1g of 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid, mix well, add 50mL of deionized water, ultrasonically disperse for 35min, add 3mL of phytic acid, stir well, add 30mL of 0.2M zinc chloride aqueous solution, ball mill for 43h, and dry to obtain graphene loaded with ionic liquid;

[0036] Step 5: Preparation of modified borax pentahydrate:

[0037] Take 5 g of borax pentahydrate and 20 mL of tetrahydrofuran solution, stir evenly to obtain a borax pentahydrate solution; take 10 g of polystyrene and 20 mL of tetrahydrofuran solution, stir evenly, add the borax pentahydrate solution, stir for 23 hours, pour into 80 mL of methanol solution, stir for 30 minutes, filter and dry to obtain modified borax pentahydrate.

[0038] Embodiment 2: A method for preparing a flame retardant polystyrene foam material, comprising the following steps:

[0039] Step 1: Take water and vinyl chloride-vinylidene chloride copolymer emulsion, mix for 15 minutes, and obtain premixed slurry A;

[0040] Take latex I, latex II, carbon liquid, deionized water, modified borax pentahydrate, aluminum hydroxide, boric acid, and graphene loaded with ionic liquid to obtain a premixed slurry B, foam, mature, mix for 70 minutes, dry, and shape to obtain a flame-retardant polystyrene foam material;

[0041] The premixed slurry A comprises the following components, in parts by weight: 25 parts of deionized water, 75 parts of vinyl chloride-vinylidene chloride copolymer latex;

[0042] The premixed slurry B includes the following components, in parts by weight: 20 parts of latex I, 60 parts of latex II, 28 parts of carbon liquid, 5 parts of deionized water, 20 parts of modified borax pentahydrate, 10 parts of aluminum hydroxide, 7 parts of boric acid, and 1 part of graphene loaded with ionic liquid;

[0043] The latex I is a carboxylated styrene-butadiene dispersion; the latex II is a water-based styrene-acrylate copolymer dispersion;

[0044] Step 2: Preparation of polystyrene:

[0045] Take 40 g of styrene, 80 mg of polyethylene glycol-4-cyano-4-(phenylcarbonylthiothiothio) valerate, and 64 mg of azobisisobutyronitrile, stir for 10 min to obtain a mixed solution, place the mixed solution in liquid nitrogen to solidify, evacuate, thaw, heat to 75°C, react for 46 h, and cool to obtain polystyrene;

[0046] Step 3: Preparation of polystyrene modified graphene:

[0047] Take 1g of graphite, 0.6g of sodium nitrate, 3g of potassium permanganate, and 25mL of concentrated sulfuric acid, react at 15°C for 2h, heat to 30°C, stir for 50min, add 100mL of deionized water, heat to 90°C, stir for 50min, add 80mL of deionized water, add 10mL of 30% hydrogen peroxide and concentrated hydrochloric acid, react until no bubbles are generated, stir at 20°C for 40min, wash until the pH value reaches 7, and dry to obtain graphene oxide;

[0048] Take 0.3 g of graphene oxide and 10 mL of tetrahydrofuran solution, stir evenly to obtain a graphene oxide solution; take 10 g of polystyrene and 20 mL of tetrahydrofuran solution, stir evenly, add the graphene oxide solution, stir for 22 h, pour into 80 mL of methanol solution, stir for 20 min, filter and dry to obtain polystyrene modified graphene;

[0049] Step 4: Preparation of graphene loaded with ionic liquid:

[0050] Take 3g of polystyrene modified graphene and 1g of 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid, mix well, add 50mL of deionized water, ultrasonically disperse for 30min, add 3mL of phytic acid, stir well, add 30mL of 0.2M zinc chloride aqueous solution, ball mill for 42h, and dry to obtain graphene loaded with ionic liquid;

[0051] Step 5: Preparation of modified borax pentahydrate:

[0052] Take 5 g of borax pentahydrate and 20 mL of tetrahydrofuran solution, stir evenly to obtain a borax pentahydrate solution; take 10 g of polystyrene and 20 mL of tetrahydrofuran solution, stir evenly, add the borax pentahydrate solution, stir for 22 hours, pour into 80 mL of methanol solution, stir for 20 minutes, filter and dry to obtain modified borax pentahydrate.

[0053] Embodiment 3: A method for preparing a flame retardant polystyrene foam material, comprising the following steps:

[0054] Step 1: Take water and vinyl chloride-vinylidene chloride copolymer emulsion, mix for 20 minutes, and obtain premixed slurry A;

[0055] Take latex I, latex II, carbon liquid, deionized water, modified borax pentahydrate, aluminum hydroxide, boric acid, and graphene loaded with ionic liquid to obtain a premixed slurry B, foam, mature, mix for 90 minutes, dry, and shape to obtain a flame-retardant polystyrene foam material;

[0056] The premixed slurry A comprises the following components, by weight: 27 parts of deionized water, 80 parts of vinyl chloride-vinylidene chloride copolymer latex;

[0057] The premixed slurry B includes the following components, in parts by weight: 22 parts of latex I, 65 parts of latex II, 30 parts of carbon liquid, 10 parts of deionized water, 21 parts of modified borax pentahydrate, 11 parts of aluminum hydroxide, 8 parts of boric acid, and 2 parts of graphene loaded with ionic liquid;

[0058] The latex I is a carboxylated styrene-butadiene dispersion; the latex II is a water-based styrene-acrylate copolymer dispersion;

[0059] Step 2: Preparation of polystyrene:

[0060] Take 40 g of styrene, 80 mg of polyethylene glycol-4-cyano-4-(phenylcarbonylthiothiothio) valerate, and 64 mg of azobisisobutyronitrile, stir for 15 min to obtain a mixed solution, place the mixed solution in liquid nitrogen to solidify, evacuate, thaw, heat to 80°C, react for 50 h, and cool to obtain polystyrene;

[0061] Step 3: Preparation of polystyrene modified graphene:

[0062] Take 1g of graphite, 0.6g of sodium nitrate, 3g of potassium permanganate, and 25mL of concentrated sulfuric acid, react at 17°C for 4h, heat to 35°C, stir for 70min, add 100mL of deionized water, heat to 95°C, stir for 70min, add 80mL of deionized water, add 10mL of 30% hydrogen peroxide and concentrated hydrochloric acid, react until no bubbles are generated, stir at 25°C for 50min, wash until the pH value reaches 7, and dry to obtain graphene oxide;

[0063] Take 0.3 g of graphene oxide and 10 mL of tetrahydrofuran solution, stir evenly to obtain a graphene oxide solution; take 10 g of polystyrene and 20 mL of tetrahydrofuran solution, stir evenly, add the graphene oxide solution, stir for 24 h, pour into 80 mL of methanol solution, stir for 40 min, filter and dry to obtain polystyrene modified graphene;

[0064] Step 4: Preparation of graphene loaded with ionic liquid:

[0065] Take 3g of polystyrene modified graphene and 1g of 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid, mix well, add 50mL of deionized water, ultrasonically disperse for 40min, add 3mL of phytic acid, stir well, add 30mL of 0.2M zinc chloride aqueous solution, ball mill for 45h, and dry to obtain graphene loaded with ionic liquid;

[0066] Step 5: Preparation of modified borax pentahydrate:

[0067] Take 5 g of borax pentahydrate and 20 mL of tetrahydrofuran solution, stir evenly to obtain a borax pentahydrate solution; take 10 g of polystyrene and 20 mL of tetrahydrofuran solution, stir evenly, add the borax pentahydrate solution, stir for 24 hours, pour into 80 mL of methanol solution, stir for 40 minutes, filter and dry to obtain modified borax pentahydrate.

[0068] Comparative Example 1: Graphene and borax pentahydrate were modified without using polystyrene, and the rest was the same as Example 1:

[0069] Step 1: taking water and vinyl chloride-vinylidene chloride copolymer emulsion, mixing for 18 minutes to obtain a premixed slurry A;

[0070] Take latex I, latex II, carbon liquid, deionized water, borax pentahydrate, aluminum hydroxide, boric acid, and graphene loaded with ionic liquid to obtain a premixed slurry B, foam, mature, mix for 80 minutes, dry, and shape to obtain a flame-retardant polystyrene foam material;

[0071] The premixed slurry A comprises the following components, by weight: 26 parts of deionized water, 78 parts of vinyl chloride-vinylidene chloride copolymer latex;

[0072] The premixed slurry B includes the following components, by weight: 22 parts of latex I, 63 parts of latex II, 29 parts of carbon liquid, 8 parts of deionized water, 20.5 parts of borax pentahydrate, 10.5 parts of aluminum hydroxide, 7.5 parts of boric acid, and 1.5 parts of graphene loaded with ionic liquid;

[0073] The latex I is a carboxylated styrene-butadiene dispersion; the latex II is a water-based styrene-acrylate copolymer dispersion;

[0074] Step 2: Preparation of graphene oxide:

[0075] Take 1g of graphite, 0.6g of sodium nitrate, 3g of potassium permanganate, and 25mL of concentrated sulfuric acid, react at 16°C for 3h, heat to 32°C, stir for 60min, add 100mL of deionized water, heat to 92°C, stir for 60min, add 80mL of deionized water, add 10mL of 30% hydrogen peroxide and concentrated hydrochloric acid, react until no bubbles are generated, stir at 22°C for 45min, wash until the pH value reaches 7, and dry to obtain graphene oxide;

[0076] Step 3: Preparation of graphene loaded with ionic liquid:

[0077] Take 3g of graphene oxide and 1g of 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid, mix well, add 50mL of deionized water, ultrasonically disperse for 35min, add 3mL of phytic acid, stir well, add 30mL of 0.2M zinc chloride aqueous solution, ball mill for 43h, and dry to obtain graphene loaded with ionic liquid.

[0078] Comparative Example 2: 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid is not loaded on graphene, and the rest is the same as Example 1:

[0079] Step 1: Take water and vinyl chloride-vinylidene chloride copolymer emulsion, mix for 18 minutes, and obtain premixed slurry A;

[0080] Take latex I, latex II, carbon liquid, deionized water, modified borax pentahydrate, aluminum hydroxide, boric acid, and flame-retardant graphene to obtain a premixed slurry B, foam, mature, mix for 80 minutes, dry, and shape to obtain a flame-retardant polystyrene foam material;

[0081] The premixed slurry A comprises the following components, by weight: 26 parts of deionized water, 78 parts of vinyl chloride-vinylidene chloride copolymer latex;

[0082] The premixed slurry B includes the following components, in parts by weight: 22 parts of latex I, 63 parts of latex II, 29 parts of carbon liquid, 8 parts of deionized water, 20.5 parts of modified borax pentahydrate, 10.5 parts of aluminum hydroxide, 7.5 parts of boric acid, and 1.5 parts of flame retardant graphene;

[0083] The latex I is a carboxylated styrene-butadiene dispersion; the latex II is a water-based styrene-acrylate copolymer dispersion;

[0084] Step 2: Preparation of polystyrene:

[0085] Take 40 g of styrene, 80 mg of polyethylene glycol-4-cyano-4-(phenylcarbonylthiothiothio) valerate, and 64 mg of azobisisobutyronitrile, stir for 12 min to obtain a mixed solution, place the mixed solution in liquid nitrogen to solidify, evacuate, thaw, heat to 78°C, react for 48 h, and cool to obtain polystyrene;

[0086] Step 3: Preparation of polystyrene modified graphene:

[0087] Take 1g of graphite, 0.6g of sodium nitrate, 3g of potassium permanganate, and 25mL of concentrated sulfuric acid, react at 16°C for 3h, heat to 32°C, stir for 60min, add 100mL of deionized water, heat to 92°C, stir for 60min, add 80mL of deionized water, add 10mL of 30% hydrogen peroxide and concentrated hydrochloric acid, react until no bubbles are generated, stir at 22°C for 45min, wash until the pH value reaches 7, and dry to obtain graphene oxide;

[0088] Take 0.3 g of graphene oxide and 10 mL of tetrahydrofuran solution, stir evenly to obtain a graphene oxide solution; take 10 g of polystyrene and 20 mL of tetrahydrofuran solution, stir evenly, add the graphene oxide solution, stir for 23 h, pour into 80 mL of methanol solution, stir for 30 min, filter and dry to obtain polystyrene modified graphene;

[0089] Step 4: Preparation of flame retardant graphene:

[0090] Take 3g of polystyrene modified graphene, add 50mL of deionized water, ultrasonically disperse for 35min, add 3mL of phytic acid, stir evenly, add 30mL of 0.2M zinc chloride aqueous solution, ball mill for 43h, and dry to obtain flame retardant graphene;

[0091] Step 5: Preparation of modified borax pentahydrate:

[0092] Take 5 g of borax pentahydrate and 20 mL of tetrahydrofuran solution, stir evenly to obtain a borax pentahydrate solution; take 10 g of polystyrene and 20 mL of tetrahydrofuran solution, stir evenly, add the borax pentahydrate solution, stir for 23 hours, pour into 80 mL of methanol solution, stir for 30 minutes, filter and dry to obtain modified borax pentahydrate.

[0093] Comparative Example 3: No phytic acid was added, and the rest was the same as Example 1:

[0094] Step 1: Take water and vinyl chloride-vinylidene chloride copolymer emulsion, mix for 18 minutes, and obtain premixed slurry A;

[0095] Take latex I, latex II, carbon liquid, deionized water, modified borax pentahydrate, aluminum hydroxide, boric acid, and graphene loaded with ionic liquid to obtain a premixed slurry B, foam, mature, mix for 80 minutes, dry, and shape to obtain a flame-retardant polystyrene foam material;

[0096] The premixed slurry A comprises the following components, by weight: 26 parts of deionized water, 78 parts of vinyl chloride-vinylidene chloride copolymer latex;

[0097] The premixed slurry B includes the following components, by weight: 22 parts of latex I, 63 parts of latex II, 29 parts of carbon liquid, 8 parts of deionized water, 20.5 parts of modified borax pentahydrate, 10.5 parts of aluminum hydroxide, 7.5 parts of boric acid, and 1.5 parts of graphene loaded with ionic liquid;

[0098] The latex I is a carboxylated styrene-butadiene dispersion; the latex II is a water-based styrene-acrylate copolymer dispersion;

[0099] Step 2: Preparation of polystyrene:

[0100] Take 40 g of styrene, 80 mg of polyethylene glycol-4-cyano-4-(phenylcarbonylthiothiothio) valerate, and 64 mg of azobisisobutyronitrile, stir for 12 min to obtain a mixed solution, place the mixed solution in liquid nitrogen to solidify, evacuate, thaw, heat to 78°C, react for 48 h, and cool to obtain polystyrene;

[0101] Step 3: Preparation of polystyrene modified graphene:

[0102] Take 1g of graphite, 0.6g of sodium nitrate, 3g of potassium permanganate, and 25mL of concentrated sulfuric acid, react at 16°C for 3h, heat to 32°C, stir for 60min, add 100mL of deionized water, heat to 92°C, stir for 60min, add 80mL of deionized water, add 10mL of 30% hydrogen peroxide and concentrated hydrochloric acid, react until no bubbles are generated, stir at 22°C for 45min, wash until the pH value reaches 7, and dry to obtain graphene oxide;

[0103] Take 0.3 g of graphene oxide and 10 mL of tetrahydrofuran solution, stir evenly to obtain a graphene oxide solution; take 10 g of polystyrene and 20 mL of tetrahydrofuran solution, stir evenly, add the graphene oxide solution, stir for 23 h, pour into 80 mL of methanol solution, stir for 30 min, filter and dry to obtain polystyrene modified graphene;

[0104] Step 4: Preparation of graphene loaded with ionic liquid:

[0105] Take 3g of polystyrene modified graphene and 1g of 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid, mix them evenly, add 50mL of deionized water, ultrasonically disperse for 35min, add 30mL of 0.2M zinc chloride aqueous solution, ball mill for 43h, and dry to obtain graphene loaded with ionic liquid;

[0106] Step 5: Preparation of modified borax pentahydrate:

[0107] Take 5 g of borax pentahydrate and 20 mL of tetrahydrofuran solution, stir evenly to obtain a borax pentahydrate solution; take 10 g of polystyrene and 20 mL of tetrahydrofuran solution, stir evenly, add the borax pentahydrate solution, stir for 23 hours, pour into 80 mL of methanol solution, stir for 30 minutes, filter and dry to obtain modified borax pentahydrate.

[0108] experiment:

[0109] The flame retardant polystyrene foam materials prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were subjected to performance tests. An oxygen index tester was used to test the limiting oxygen index of the polystyrene foam materials. With reference to GB / T6594.2-2003, a tensile testing machine was used to test the tensile strength of the polystyrene foam materials. The data obtained are as follows:

[0110] Limiting oxygen index / % Tensile strength / Mpa Example 1 32.7 1.32 Example 2 32.5 1.31 Example 3 32.8 1.33 Comparative Example 1 30.1 1.07 Comparative Example 2 27.4 1.30 Comparative Example 3 28.2 1.28

[0111] Conclusion: From the data comparison in the table, it can be seen that comparative example 1 does not use polystyrene to modify graphene and borax pentahydrate. At this time, the dispersibility of graphene and borax pentahydrate in the polystyrene foam material matrix is ​​poor, and the flame retardancy and mechanical properties of the polystyrene foam material decrease. Comparative example 2 does not load 1-butyl-3-methylimidazole hexafluorophosphate ionic liquid on graphene, and the flame retardancy of the polystyrene foam material decreases at this time. Comparative example 3 does not add phytic acid, the load of metal zinc ions decreases, and the flame retardancy of the polystyrene foam material greatly decreases. Embodiments 1-3 of the present invention use polystyrene to modify expanded graphite and borax pentahydrate, so that the modified graphene and borax pentahydrate have better compatibility in the polystyrene foam material matrix, and the flame retardancy and mechanical properties of the polystyrene foam material are strengthened. 1-Butyl-3-methylimidazolium hexafluorophosphate ionic liquid is loaded on graphene to improve the flame retardant properties of graphene, and then phytic acid is added for further modification to improve the flame retardant properties of polystyrene foam. Finally, zinc chloride aqueous solution is added to introduce metal zinc ions through chelation to promote the formation of carbon, thereby further improving the flame retardant properties of polystyrene foam.

[0112] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A method for preparing a flame retardant polystyrene foam material, characterized in that: The following steps are involved: Step 1: Take water and vinyl chloride-vinylidene chloride copolymer emulsion, mix for 15-20 minutes, and obtain premixed slurry A; Step 2: Take latex I, latex II, carbon liquid, deionized water, modified borax pentahydrate, aluminum hydroxide, boric acid, and graphene loaded with ionic liquid to obtain a premixed slurry B, foam, mature, mix for 70-90 minutes, dry, and shape to obtain a flame-retardant polystyrene foam material.

2. The method for preparing a flame retardant polystyrene foam material according to claim 1, characterized in that: The premixed slurry A comprises the following components, by weight: 25-27 parts of deionized water, 75-80 parts of vinyl chloride-vinylidene chloride copolymer latex; The premixed slurry B includes the following components, calculated by weight: 20-22 parts of latex I, 60-65 parts of latex II, 28-30 parts of carbon liquid, 5-10 parts of deionized water, 20-21 parts of modified borax pentahydrate, 10-11 parts of aluminum hydroxide, 7-8 parts of boric acid, and 1-2 parts of graphene loaded with ionic liquid.

3. The method for preparing a flame retardant polystyrene foam material according to claim 1, characterized in that: The latex I is a carboxylated styrene-butadiene dispersion; the latex II is an aqueous styrene-acrylate copolymer dispersion.

4. The method for preparing a flame retardant polystyrene foam material according to claim 1, characterized in that: The preparation method of the graphene loaded with ionic liquid is as follows: polystyrene modified graphene and 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid are mixed evenly, deionized water is added, ultrasonic dispersion is performed for 30-40 minutes, phytic acid is added, stirring is performed evenly, a zinc chloride aqueous solution is added, ball milling is performed for 42-45 hours, and drying is performed to obtain the graphene loaded with ionic liquid.

5. The method for preparing a flame retardant polystyrene foam material according to claim 4, characterized in that: The preparation method of the polystyrene modified graphene is as follows: taking graphene oxide and tetrahydrofuran solution, stirring evenly to obtain a graphene oxide solution; taking polystyrene and tetrahydrofuran solution, stirring evenly, adding the graphene oxide solution, stirring for 22-24 hours, pouring into a methanol solution, stirring for 20-40 minutes, filtering, and drying to obtain polystyrene modified graphene.

6. The method for preparing a flame retardant polystyrene foam material according to claim 2, characterized in that: The preparation method of the modified borax pentahydrate is as follows: taking borax pentahydrate and tetrahydrofuran solution, stirring evenly to obtain a borax pentahydrate solution; taking polystyrene and tetrahydrofuran solution, stirring evenly, adding the borax pentahydrate solution, stirring for 22-24 hours, pouring into a methanol solution, stirring for 20-40 minutes, filtering, and drying to obtain the modified borax pentahydrate.

7. A method for preparing a flame retardant polystyrene foam material according to any one of claims 5 to 6, characterized in that: The preparation method of the polystyrene comprises the following steps: taking styrene, polyethylene glycol-4-cyano-4-(phenylcarbonylthiothiothio) valerate and azobisisobutyronitrile, stirring for 10-15 minutes to obtain a mixed solution, placing the mixed solution in liquid nitrogen for solidification, vacuumizing, thawing, heating to 75-80° C. for reaction for 46-50 hours, and cooling to obtain the polystyrene.

8. The method for preparing a flame retardant polystyrene foam material according to claim 5, characterized in that: The preparation method of the graphene oxide is as follows: taking graphite, sodium nitrate, potassium permanganate and concentrated sulfuric acid, reacting at 15-17° C. for 2-4 hours, heating to 30-35° C., stirring for 50-70 minutes, adding deionized water, heating to 90-95° C., stirring for 50-70 minutes, adding deionized water, adding hydrogen peroxide and concentrated hydrochloric acid, reacting until no bubbles are generated, stirring at 20-25° C. for 40-50 minutes, washing, and drying to obtain graphene oxide.

9. The flame retardant polystyrene foam material prepared according to the method for preparing a flame retardant polystyrene foam material according to any one of claims 1 to 8.