Preparation method of a highly flame-retardant graphene polystyrene board

Abstract

The invention discloses a preparation method of a highly flame-retardant graphene polystyrene board. Modified polystyrene is added into a mold, and under the conditions of a steam temperature of 110 - 130 °C and a pressure of 0.3 - 0.5 MPa, it is heat-insulated for 30 - 60 s to obtain the highly flame-retardant graphene polystyrene board. When the polystyrene board burns, phosphorus compounds in the modified filler decompose to form a liquid phosphoric acid film to protect the polystyrene board matrix. The phosphoric acid is further dehydrated to form metaphosphoric acid, and the metaphosphoric acid polymerizes to form poly metaphosphoric acid. These substances can form stable cross-linked solid substances and form a carbonized layer. The internal silicon and boron elements can promote the formation of a ceramicized silicon carbide layer in the carbonized layer, and the nitrogen element will generate a large amount of gas, thereby causing the ceramicized silicon carbide layer to expand. The heat insulation and oxygen isolation effect of this expanded ceramicized silicon carbide layer is better. The continuous sheet structure of graphene can effectively prevent oxygen from entering the interior of the material, thereby preventing the progress of combustion and achieving the flame-retardant effect.

Description

Technical Field

[0001] The present invention relates to the technical field of polystyrene board material preparation, and specifically relates to a preparation method of a highly flame-retardant graphene polystyrene board. Background Art

[0002] Polystyrene board, also known as EPS board, is based on expandable polystyrene raw materials and is made through a series of processes such as pre-expansion, ripening, molding, drying, and cutting. It is widely used in multiple fields, including construction, packaging, refrigeration, freezing, ships, industrial casting, etc., and is mainly used as heat insulation, sound insulation, and earthquake-resistant materials. Polystyrene board has a series of advantages, such as light weight, low cost, sound insulation, earthquake resistance, low thermal conductivity, good insulation, small water absorption, and easy molding. These characteristics make it highly favored in the construction industry, providing a lightweight, economical, and efficient heat insulation solution. Although polystyrene board performs well in many aspects, as a foamed organic material, its flame retardant effect is extremely poor, and it burns rapidly when encountering an open flame, affecting its use safety. Summary of the Invention

[0003] The purpose of the present invention is to provide a preparation method of a highly flame-retardant graphene polystyrene board, which solves the problem that the polystyrene board is extremely flammable at the present stage.

[0004] The purpose of the present invention can be achieved through the following technical solutions:

[0005] A preparation method of a highly flame-retardant graphene polystyrene board specifically includes the following steps:

[0006] Step A1: Mix graphene oxide, 3-aminopropyltriethoxysilane, dicyclohexylcarbodiimide, and toluene, introduce nitrogen protection, and react for 2 - 3 h under the conditions of a rotation speed of 200 - 300 r / min and a temperature of 25 - 30 °C to obtain modified graphene. Mix the modified graphene, modifier, 3-aminopropyltriethoxysilane, and dimethyl sulfoxide, and react for 10 - 15 h under the conditions of a rotation speed of 300 - 500 r / min and a temperature of 60 - 70 °C, then add ammonium fluoride, cool down to 20 - 25 °C, and continue to react for 20 - 25 h to obtain modified filler;

[0007] Step A2: Mix the modified filler, maleic anhydride, and DMF, and react for 1 - 1.5 h under the conditions of a rotation speed of 120 - 150 r / min and a temperature of 20 - 25 °C, then add acetic anhydride and sodium acetate, heat up to 100 - 105 °C, and continue to react for 3 - 5 h to obtain flame-retardant filler;

[0008] Step A3: Mix styrene, flame retardant filler, and pentane evenly. Under the conditions of a rotation speed of 120 - 150 r / min and a temperature of 80 - 85 °C, stir and add potassium persulfate, and react for 3 - 5 h to obtain modified polystyrene. Add the modified polystyrene into a mold, and keep it warm for 30 - 60 s under the conditions of a steam temperature of 110 - 130 °C and a pressure of 0.3 - 0.5 MPa to obtain a highly flame-retardant graphene polystyrene board.

[0009] Further, in the preparation process of the modified graphene in Step A1, the molar ratio of carboxyl groups on graphene oxide, 3-aminopropyltriethoxysilane, and dicyclohexylcarbodiimide is 1:1:1.1. In the preparation process of the modified filler, the dosage ratio of modified graphene, modifier, 3-aminopropyltriethoxysilane, and ammonium fluoride is 2 g:3 g:3 mL:0.3 g.

[0010] Further, the molar ratio of amino groups, maleic anhydride, acetic anhydride, and sodium acetate on the modified filler in Step A2 is 5 mmol:5 mmol:1 mL:1 mmol.

[0011] Further, the mass ratio of styrene, flame retardant filler, and pentane in Step A3 is 100:5:1 - 3, and the dosage of potassium persulfate is 5‰ of the mass of styrene.

[0012] Further, the modifier is prepared by the following steps:

[0013] Step B1: Mix 4-bromophenol, sodium hydroxide, and tetrahydrofuran evenly, introduce nitrogen protection. Under the conditions of a rotation speed of 200 - 300 r / min and a temperature of 80 - 85 °C, stir and reflux for 1 - 1.5 h, then add hexachlorocyclotriphosphazene and react for 10 - 15 h to obtain Intermediate 1. Mix Intermediate 1 and tetrahydrofuran evenly, introduce nitrogen protection. Under the conditions of a rotation speed of 60 - 80 r / min and a temperature of -78 °C, stir and add n-butyllithium, and react for 2 - 3 h, then add triisopropyl borate and continue to react for 2 - 3 h to obtain Intermediate 2;

[0014] Step B2: Mix Intermediate 2, 3,4-dihydroxybenzaldehyde, and tetrahydrofuran evenly. Under the conditions of a rotation speed of 120 - 150 r / min and a temperature of 80 - 85 °C, stir and add p-toluenesulfonic acid, and react for 6 - 8 h, then adjust the pH to neutral to obtain Intermediate 3. Mix Intermediate 3, 4-vinyl aniline, and tetrahydrofuran evenly. Under the conditions of a rotation speed of 200 - 300 r / min, a temperature of 70 - 80 °C, and a pH value of 5 - 6, react for 1 - 1.5 h to obtain Intermediate 4;

[0015] Step B3: Mix intermediate 4, 3-mercaptopropyltrimethoxysilane, 2-hydroxy-2-methyl-1-phenyl-1-propanone and DMF, and react for 2 - 3 h under the conditions of a rotation speed of 200 - 300 r / min, a temperature of 20 - 25 °C, and irradiation with 365 nm ultraviolet light to obtain intermediate 5. Mix intermediate 5, DOPO and cyclohexane, introduce nitrogen protection, and react for 2 - 3 h under the conditions of a rotation speed of 300 - 500 r / min and a temperature of 90 - 95 °C to obtain the modifier.

[0016] Furthermore, the molar ratio of 4-bromophenol, sodium hydroxide and hexachlorocyclotriphosphazene described in step B1 is 70:75:9, and the molar ratio of intermediate 1, n-butyllithium and triisopropyl borate is 1:8:10.

[0017] Furthermore, the molar ratio of intermediate 2 and 3,4-dihydroxybenzaldehyde described in step B2 is 1:6, the dosage of p-toluenesulfonic acid is 2% of the mass of 3,4-dihydroxybenzaldehyde, and the molar ratio of intermediate 3 and 4-vinyl aniline is 1:6.

[0018] Furthermore, the molar ratio of intermediate 4 and 3-mercaptopropyltrimethoxysilane described in step B3 is 1:6, the dosage of 2-hydroxy-2-methyl-1-phenyl-1-propanone is 1% of the mass of 3-mercaptopropyltrimethoxysilane, and the molar ratio of intermediate 5 and DOPO is 1:6.

[0019] The beneficial effects of the present invention: A highly flame-retardant graphene polystyrene board prepared by the present invention uses graphene oxide as a raw material and is treated with 3-aminopropyltriethoxysilane, so that the carboxyl group on graphene oxide and the amino group on 3-aminopropyltriethoxysilane undergo a dehydration reaction to obtain modified graphene. The modified graphene, the modifier and 3-aminopropyltriethoxysilane are dehydrated and condensed to form polyhedral oligomeric silsesquioxane on the surface to obtain a modified filler. The modified filler is treated with maleic anhydride, so that the amino group on the modified filler reacts with maleic anhydride to form maleimide to obtain a flame-retardant filler. Styrene, the flame-retardant filler and pentane are mixed evenly, and under the action of potassium persulfate, styrene and maleic anhydride on the surface of the flame-retardant filler are polymerized to obtain modified polystyrene. Under high temperature and high pressure, pentane is vaporized, and then a highly flame-retardant graphene polystyrene board is obtained.

[0020] The modifier is prepared by reacting 4-bromophenol with hexachlorocyclotriphosphazene, causing the phenolic hydroxyl group on 4-bromophenol to react with the chlorine atom sites on hexachlorocyclotriphosphazene to obtain intermediate 1. Intermediate 1 is then reacted with triisopropyl borate to convert the bromine atom sites on intermediate 1 into boronic acid groups, resulting in intermediate 2. Intermediate 2 is reacted with 3,4-dihydroxybenzaldehyde, causing the boronic acid groups on intermediate 2 to react with the catechol on 3,4-dihydroxybenzaldehyde to obtain intermediate 3. Intermediate 3 is reacted with 4-vinyl aniline, causing the aldehyde group on intermediate 3 to react with the amino group on 4-vinyl aniline to obtain intermediate 4. Intermediate 4 is reacted with 3-mercaptopropyltrimethoxysilane, causing the double bond on intermediate 4 to react with the mercapto group on 3-mercaptopropyltrimethoxysilane to obtain intermediate 5. Intermediate 5 is reacted with DOPO, causing the carbon-nitrogen double bond on intermediate 5 to react with the phosphorus-hydrogen bond on DOPO to obtain the modifier.

[0021] When the polystyrene board burns, the phosphorus compounds in the modified filler decompose to form a liquid phosphoric acid film, which protects the polystyrene board matrix. The phosphoric acid further dehydrates to form metaphosphoric acid, and the metaphosphoric acid polymerizes to form poly metaphosphoric acid. These substances can form a stable cross-linked solid substance and a carbonized layer. The internal silicon and boron elements can promote the formation of a ceramicized silicon-carbon layer in the carbonized layer, and the nitrogen element will generate a large amount of gas, which causes the ceramicized silicon-carbon layer to expand. This expanded ceramicized silicon-carbon layer has a better heat insulation and oxygen isolation effect. The continuous sheet structure of graphene can effectively prevent oxygen from entering the interior of the material, thereby preventing the combustion from proceeding and achieving a flame retardant effect. Specific embodiments

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0023] Example 1. A preparation method of a highly flame-retardant graphene polystyrene board specifically includes the following steps:

[0024] Step A1: Graphene oxide, 3-aminopropyltriethoxysilane, dicyclohexylcarbodiimide and toluene are mixed, and nitrogen protection is introduced. The reaction is carried out for 2 h under the conditions of a rotation speed of 200 r / min and a temperature of 25 °C to obtain modified graphene. The modified graphene, the modifier, 3-aminopropyltriethoxysilane and dimethyl sulfoxide are mixed, and the reaction is carried out for 10 h under the conditions of a rotation speed of 300 r / min and a temperature of 60 °C. Then ammonium fluoride is added, and the temperature is lowered to 20 °C and the reaction is continued for 20 h to obtain the modified filler;

[0025] Step A2: Mix the modified filler, maleic anhydride, and DMF. React for 1 h under the conditions of a rotation speed of 120 r / min and a temperature of 20 °C. Then add acetic anhydride and sodium acetate, raise the temperature to 100 °C, and continue to react for 3 h to obtain the flame-retardant filler.

[0026] Step A3: Mix styrene, the flame-retardant filler, and pentane evenly. Stir and add potassium persulfate under the conditions of a rotation speed of 120 r / min and a temperature of 80 °C, and react for 3 h to obtain modified polystyrene. Add the modified polystyrene into a mold and keep it warm for 30 s under the conditions of a steam temperature of 110 °C and a pressure of 0.3 MPa to obtain the high-flame-retardant graphene polystyrene board.

[0027] In the preparation process of the modified graphene described in Step A1, the molar ratio of the carboxyl group on graphene oxide, 3-aminopropyltriethoxysilane, and dicyclohexylcarbodiimide is 1:1:1.1. In the preparation process of the modified filler, the dosage ratio of the modified graphene, modifier, 3-aminopropyltriethoxysilane, and ammonium fluoride is 2 g:3 g:3 mL:0.3 g.

[0028] The amounts of amino group, maleic anhydride, acetic anhydride, and sodium acetate on the modified filler described in Step A2 are 5 mmol:5 mmol:1 mL:1 mmol.

[0029] The mass ratio of styrene, the flame-retardant filler, and pentane described in Step A3 is 100:5:1, and the dosage of potassium persulfate is 5‰ of the mass of styrene.

[0030] The modifier is prepared by the following steps:

[0031] Step B1: Mix 4-bromophenol, sodium hydroxide, and tetrahydrofuran evenly, introduce nitrogen protection, stir and reflux for 1 h under the conditions of a rotation speed of 200 r / min and a temperature of 80 °C, then add hexachlorocyclotriphosphazene and react for 10 h to obtain Intermediate 1. Mix Intermediate 1 and tetrahydrofuran evenly, introduce nitrogen protection, stir and add n-butyllithium under the conditions of a rotation speed of 60 r / min and a temperature of -78 °C, react for 2 h, then add triisopropyl borate and continue to react for 2 - 3 h to obtain Intermediate 2.

[0032] Step B2: Mix Intermediate 2, 3,4-dihydroxybenzaldehyde, and tetrahydrofuran evenly, stir and add p-toluenesulfonic acid under the conditions of a rotation speed of 120 r / min and a temperature of 80 °C, react for 6 h, then adjust the pH to neutral to obtain Intermediate 3. Mix Intermediate 3, 4-vinyl aniline, and tetrahydrofuran evenly, and react for 1 h under the conditions of a rotation speed of 200 r / min, a temperature of 70 °C, and a pH value of 5 to obtain Intermediate 4.

[0033] Step B3: Mix intermediate 4, 3-mercaptopropyltrimethoxysilane, 2-hydroxy-2-methyl-1-phenyl-1-propanone and DMF, and carry out a reaction for 2 h under the conditions of a rotation speed of 200 r / min, a temperature of 20 °C and irradiation with ultraviolet light at 365 nm to obtain intermediate 5. Mix intermediate 5, DOPO and cyclohexane, introduce nitrogen protection, and carry out a reaction for 2 h under the conditions of a rotation speed of 300 r / min and a temperature of 90 °C to obtain a modifier.

[0034] The molar ratio of 4-bromophenol, sodium hydroxide and hexachlorocyclotriphosphazene described in Step B1 is 70:75:9, and the molar ratio of intermediate 1, n-butyllithium and triisopropyl borate is 1:8:10.

[0035] The molar ratio of intermediate 2 and 3,4-dihydroxybenzaldehyde described in Step B2 is 1:6, the dosage of p-toluenesulfonic acid is 2% of the mass of 3,4-dihydroxybenzaldehyde, and the molar ratio of intermediate 3 and 4-vinyl aniline is 1:6.

[0036] The molar ratio of intermediate 4 and 3-mercaptopropyltrimethoxysilane described in Step B3 is 1:6, the dosage of 2-hydroxy-2-methyl-1-phenyl-1-propanone is 1% of the mass of 3-mercaptopropyltrimethoxysilane, and the molar ratio of intermediate 5 and DOPO is 1:6.

[0037] Example 2. A preparation method of a highly flame-retardant graphene polystyrene board specifically comprises the following steps:

[0038] Step A1: Mix graphene oxide, 3-aminopropyltriethoxysilane, dicyclohexylcarbodiimide and toluene, introduce nitrogen protection, and carry out a reaction for 2.5 h under the conditions of a rotation speed of 200 r / min and a temperature of 28 °C to obtain modified graphene. Mix the modified graphene, the modifier, 3-aminopropyltriethoxysilane and dimethyl sulfoxide, carry out a reaction for 13 h under the conditions of a rotation speed of 500 r / min and a temperature of 65 °C, then add ammonium fluoride, cool down to 20 °C, and continue to react for 25 h to obtain a modified filler.

[0039] Step A2: Mix the modified filler, maleic anhydride and DMF, carry out a reaction for 1 h under the conditions of a rotation speed of 120 r / min and a temperature of 25 °C, then add acetic anhydride and sodium acetate, raise the temperature to 105 °C, and continue to react for 4 h to obtain a flame-retardant filler.

[0040] Step A3: Mix styrene, the flame-retardant filler and pentane evenly, stir and add potassium persulfate under the conditions of a rotation speed of 120 r / min and a temperature of 85 °C, and carry out a reaction for 4 h to obtain modified polystyrene. Add the modified polystyrene into a mold, and keep it warm for 45 s under the conditions of a steam temperature of 120 °C and a pressure of 0.4 MPa to obtain a highly flame-retardant graphene polystyrene board.

[0041] In the preparation process of the modified graphene described in step A1, the molar ratio of carboxyl groups on graphene oxide, 3-aminopropyltriethoxysilane, and dicyclohexylcarbodiimide is 1:1:1.1. In the preparation process of the modified filler, the dosage ratio of modified graphene, modifier, 3-aminopropyltriethoxysilane, and ammonium fluoride is 2 g:3 g:3 mL:0.3 g.

[0042] For the amino groups, maleic anhydride, acetic anhydride, and sodium acetate on the modified filler described in step A2, the ratio is 5 mmol:5 mmol:1 mL:1 mmol.

[0043] In step A3, the mass ratio of styrene, flame retardant filler, and pentane is 100:5:2, and the dosage of potassium persulfate is 5‰ of the mass of styrene.

[0044] The modifier is prepared by the following steps:

[0045] Step B1: Mix 4-bromophenol, sodium hydroxide, and tetrahydrofuran evenly, introduce nitrogen protection, under the conditions of a rotation speed of 200 r / min and a temperature of 85 °C, stir and reflux for 1 h, then add hexachlorocyclotriphosphazene and react for 15 h to obtain intermediate 1. Mix intermediate 1 and tetrahydrofuran evenly, introduce nitrogen protection, under the conditions of a rotation speed of 60 r / min and a temperature of -78 °C, stir and add n-butyllithium, react for 3 h, then add triisopropyl borate and continue to react for 2 h to obtain intermediate 2;

[0046] Step B2: Mix intermediate 2, 3,4-dihydroxybenzaldehyde, and tetrahydrofuran evenly, under the conditions of a rotation speed of 120 r / min and a temperature of 85 °C, stir and add p-toluenesulfonic acid, react for 7 h, then adjust the pH to neutral to obtain intermediate 3. Mix intermediate 3, 4-vinyl aniline, and tetrahydrofuran evenly, under the conditions of a rotation speed of 200 r / min, a temperature of 75 °C, and a pH value of 5, react for 1.5 h to obtain intermediate 4;

[0047] Step B3: Mix intermediate 4, 3-mercaptopropyltrimethoxysilane, 2-hydroxy-2-methyl-1-phenyl-1-propanone, and DMF, under the conditions of a rotation speed of 200 r / min, a temperature of 25 °C, and irradiation with 365 nm ultraviolet light, react for 2 h to obtain intermediate 5. Mix intermediate 5, DOPO, and cyclohexane, introduce nitrogen protection, under the conditions of a rotation speed of 500 r / min and a temperature of 90 °C, react for 3 h to obtain the modifier.

[0048] In step B1, the molar ratio of 4-bromophenol, sodium hydroxide, and hexachlorocyclotriphosphazene is 70:75:9, and the molar ratio of intermediate 1, n-butyllithium, and triisopropyl borate is 1:8:10.

[0049] For the intermediate 2 and 3,4-dihydroxybenzaldehyde described in step B2, the molar ratio is 1:6, the dosage of p-toluenesulfonic acid is 2% of the mass of 3,4-dihydroxybenzaldehyde, and for the intermediate 3 and 4-vinyl aniline, the molar ratio is 1:6.

[0050] For the intermediate 4 and 3-mercaptopropyltrimethoxysilane described in step B3, the molar ratio is 1:6, the dosage of 2-hydroxy-2-methyl-1-phenyl-1-propanone is 1% of the mass of 3-mercaptopropyltrimethoxysilane, and for the intermediate 5 and DOPO, the molar ratio is 1:6.

[0051] Example 3. A preparation method of a highly flame-retardant graphene polystyrene board, specifically comprising the following steps:

[0052] Step A1: Mix graphene oxide, 3-aminopropyltriethoxysilane, dicyclohexylcarbodiimide and toluene, introduce nitrogen protection, and carry out a reaction for 3 h under the conditions of a rotation speed of 300 r / min and a temperature of 30 °C to obtain modified graphene. Mix the modified graphene, modifier, 3-aminopropyltriethoxysilane and dimethyl sulfoxide, and carry out a reaction for 15 h under the conditions of a rotation speed of 500 r / min and a temperature of 70 °C. Then add ammonium fluoride, cool down to 25 °C, and continue the reaction for 25 h to obtain a modified filler.

[0053] Step A2: Mix the modified filler, maleic anhydride and DMF, and carry out a reaction for 1.5 h under the conditions of a rotation speed of 150 r / min and a temperature of 25 °C. Then add acetic anhydride and sodium acetate, heat up to 105 °C, and continue the reaction for 5 h to obtain a flame-retardant filler.

[0054] Step A3: Mix styrene, the flame-retardant filler and pentane evenly, stir and add potassium persulfate under the conditions of a rotation speed of 150 r / min and a temperature of 85 °C, and carry out a reaction for 5 h to obtain modified polystyrene. Add the modified polystyrene into a mold, and keep it warm for 60 s under the conditions of a steam temperature of 130 °C and a pressure of 0.5 MPa to obtain a highly flame-retardant graphene polystyrene board.

[0055] In the preparation process of the modified graphene described in step A1, the molar ratio of the carboxyl group on graphene oxide, 3-aminopropyltriethoxysilane and dicyclohexylcarbodiimide is 1:1:1.1, and in the preparation process of the modified filler, the dosage ratio of the modified graphene, modifier, 3-aminopropyltriethoxysilane and ammonium fluoride is 2 g:3 g:3 mL:0.3 g.

[0056] For the amino group, maleic anhydride, acetic anhydride and sodium acetate on the modified filler described in step A2, it is 5 mmol:5 mmol:1 mL:1 mmol.

[0057] The mass ratio of styrene, flame retardant filler, and pentane described in Step A3 is 100:5:3, and the dosage of potassium persulfate is 5‰ of the mass of styrene.

[0058] The modifier is prepared by the following steps:

[0059] Step B1: Mix 4-bromophenol, sodium hydroxide, and tetrahydrofuran evenly, introduce nitrogen protection, stir and reflux for 1.5 h at a rotation speed of 300 r / min and a temperature of 85 °C, then add hexachlorocyclotriphosphazene and react for 15 h to obtain Intermediate 1. Mix Intermediate 1 and tetrahydrofuran evenly, introduce nitrogen protection, stir and add n-butyllithium at a rotation speed of 80 r / min and a temperature of -78 °C, react for 3 h, then add triisopropyl borate and continue to react for 3 h to obtain Intermediate 2;

[0060] Step B2: Mix Intermediate 2, 3,4-dihydroxybenzaldehyde, and tetrahydrofuran evenly, stir and add p-toluenesulfonic acid at a rotation speed of 150 r / min and a temperature of 85 °C, react for 8 h, then adjust the pH to neutral to obtain Intermediate 3. Mix Intermediate 3, 4-vinyl aniline, and tetrahydrofuran evenly, and react for 1.5 h at a rotation speed of 300 r / min, a temperature of 80 °C, and a pH value of 6 to obtain Intermediate 4;

[0061] Step B3: Mix Intermediate 4, 3-mercaptopropyltrimethoxysilane, 2-hydroxy-2-methyl-1-phenyl-1-propanone, and DMF, and react for 3 h at a rotation speed of 300 r / min, a temperature of 25 °C, and under 365 nm ultraviolet light irradiation to obtain Intermediate 5. Mix Intermediate 5, DOPO, and cyclohexane, introduce nitrogen protection, and react for 3 h at a rotation speed of 500 r / min and a temperature of 95 °C to obtain the modifier.

[0062] The molar ratio of 4-bromophenol, sodium hydroxide, and hexachlorocyclotriphosphazene described in Step B1 is 70:75:9, and the molar ratio of Intermediate 1, n-butyllithium, and triisopropyl borate is 1:8:10.

[0063] The molar ratio of Intermediate 2 and 3,4-dihydroxybenzaldehyde described in Step B2 is 1:6, the dosage of p-toluenesulfonic acid is 2% of the mass of 3,4-dihydroxybenzaldehyde, and the molar ratio of Intermediate 3 and 4-vinyl aniline is 1:6.

[0064] The molar ratio of Intermediate 4 and 3-mercaptopropyltrimethoxysilane described in Step B3 is 1:6, the dosage of 2-hydroxy-2-methyl-1-phenyl-1-propanone is 1% of the mass of 3-mercaptopropyltrimethoxysilane, and the molar ratio of Intermediate 5 and DOPO is 1:6.

[0065] Comparative Example 1: Compared with Example 1, a modified filler was used instead of the flame retardant filler, and the remaining steps were the same.

[0066] Comparative Example 2: Compared with Example 1, no modifier was added, and the remaining steps were the same.

[0067] Comparative Example 3: Compared with Example 1, intermediate 5 was used instead of the modifier, and the remaining steps were the same.

[0068] The polystyrene boards prepared in Examples 1 - 3 and Comparative Examples 1 - 3 were made into specimens of 125 mm × 13 mm × 10 mm according to the standard of GB / T 2408 - 2008 to detect the vertical burning grade, and made into specimens of 130 mm × 10 mm × 10 mm according to the standard of GB / T 2406.2 - 2009 to detect the limiting oxygen index. The test results are shown in Table 1 below.

[0069] Table 1

[0070] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Vertical burning rating V0 V0 V0 V1 V2 V1 Limiting oxygen index % 40.4 41.5 41.9 35.7 21.6 33.4

[0071] It can be seen from Table 1 above that the present application has a good flame retardant effect.

[0072] The above content is only an example and explanation of the concept of the present invention. Those skilled in the art of this technology can make various modifications or supplements to the described specific embodiments or use similar methods for substitution, as long as they do not deviate from the concept of the invention or exceed the scope defined by this claim book, they shall fall within the protection scope of the present invention.

Claims

1. A preparation method of a high flame-retardant graphene polystyrene board, characterized in that: Specifically, it includes the following steps: Step A1: Mix graphene oxide, 3-aminopropyltriethoxysilane, dicyclohexylcarbodiimide and toluene, introduce nitrogen for protection, and carry out a reaction to obtain modified graphene. After mixing and reacting the modified graphene, modifier, 3-aminopropyltriethoxysilane and dimethyl sulfoxide, add ammonium fluoride, cool down and continue the reaction to obtain a modified filler; Step A2: After mixing and reacting the modified filler, maleic anhydride and DMF, add acetic anhydride and sodium acetate, heat up and continue the reaction to obtain a flame-retardant filler; Step A3: Mix styrene, flame-retardant filler and pentane, stir and add potassium persulfate, and carry out a reaction to obtain modified polystyrene. Add the modified polystyrene into a mold and perform heat preservation treatment under high temperature and high pressure to obtain a highly flame-retardant graphene polystyrene board; The modifier is prepared by the following steps: Step B1: Mix 4-bromophenol, sodium hydroxide and tetrahydrofuran evenly, introduce nitrogen for protection, stir and reflux, then add hexachlorocyclotriphosphazene, and carry out a reaction to obtain intermediate 1. Mix intermediate 1 and tetrahydrofuran evenly, introduce nitrogen for protection, stir and add n-butyllithium, and after the reaction, add triisopropyl borate and continue the reaction to obtain intermediate 2; Step B2: Mix intermediate 2, 3,4-dihydroxybenzaldehyde and tetrahydrofuran, stir and add p-toluenesulfonic acid, and after the reaction, adjust the pH to neutral to obtain intermediate 3. Mix intermediate 3, 4-vinyl aniline and tetrahydrofuran and carry out a reaction to obtain intermediate 4; Step B3: Mix intermediate 4, 3-mercaptopropyltrimethoxysilane, 2-hydroxy-2-methyl-1-phenyl-1-propanone and DMF and carry out a reaction to obtain intermediate 5. Mix intermediate 5, DOPO and cyclohexane, introduce nitrogen for protection, and carry out a reaction to obtain the modifier.

2. The preparation method of a highly flame-retardant graphene polystyrene board according to claim 1, characterized in that: In the preparation process of the modified graphene in Step A1, the molar ratio of the carboxyl group on graphene oxide, 3-aminopropyltriethoxysilane and dicyclohexylcarbodiimide is 1:1:1.

1. In the preparation process of the modified filler, the dosage ratio of modified graphene, modifier, 3-aminopropyltriethoxysilane and ammonium fluoride is 2g:3g:3mL:0.3g.

3. The preparation method of a highly flame-retardant graphene polystyrene board according to claim 1, characterized in that: In Step A2, the dosage ratio of the amino group on the modified filler, maleic anhydride, acetic anhydride and sodium acetate is 5mmol:5mmol:1mL:1mmol.

4. The preparation method of a highly flame-retardant graphene polystyrene board according to claim 1, characterized in that: In Step A3, the mass ratio of styrene, flame-retardant filler and pentane is 100:5:1 - 3.

5. The preparation method of a highly flame-retardant graphene polystyrene board according to claim 1, characterized in that: In Step B1, the molar ratio of 4-bromophenol, sodium hydroxide, tetrahydrofuran and hexachlorocyclotriphosphazene is 70:75:

9. The molar ratio of intermediate 1, n-butyllithium, tetrahydrofuran and triisopropyl borate is 1:8:

10.

6. The preparation method of a highly flame-retardant graphene polystyrene board according to claim 1, characterized in that: In Step B2, the molar ratio of intermediate 2 and 3,4-dihydroxybenzaldehyde is 1:

6. The molar ratio of intermediate 3 and 4-vinyl aniline is 1:

6.

7. The preparation method of a highly flame-retardant graphene polystyrene board according to claim 1, characterized in that: In Step B3, the molar ratio of intermediate 4 and 3-mercaptopropyltrimethoxysilane is 1:

6. The molar ratio of intermediate 5 and DOPO is 1:6.