Heat-resistant polystyrene foam material and preparation method thereof
By copolymerizing modified graphene and styrene monomer, heat-resistant polystyrene foaming materials are prepared, which solves the problem of insufficient heat resistance and mechanical properties of traditional materials at high temperatures, and achieves the improvement of the stability and strength of the materials in high temperature environments.
Patent Information
- Application Number
- CN202510365730.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-26
- Publication Date
- 2025-08-12
AI Technical Summary
Traditional polystyrene foaming materials have insufficient heat resistance and mechanical properties under high temperature environments, resulting in softening and deformation of the materials under high temperature conditions, and cannot meet the application needs in the fields of high performance and high reliability.
By synthesizing a modifier with an acetal spiral ring structure, graphene oxide is modified and copolymerized with styrene monomer to prepare heat-resistant polystyrene foaming material. Modified graphene is used as a nucleating agent to promote polystyrene crystallization, and improve the crystallinity and intermolecular force of the material.
The heat resistance and mechanical properties of polystyrene foamed materials are significantly improved, so that their thermal stability and mechanical strength in high temperature environments are significantly improved, the heat resistance temperature reaches 110-118℃, and the impact strength is increased to 0.42-0.45KJ.m-2.
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Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of foam materials, and in particular relates to a heat-resistant polystyrene foam material and a preparation method thereof. Background Art
[0002] Polystyrene foam materials are widely used in packaging, building insulation, automotive interiors, and other fields due to their lightweight, thermal insulation, and cushioning properties. However, traditional polystyrene foam materials suffer from significant heat resistance issues. Their heat deformation temperature is relatively low, typically around 70-90°C, making them difficult to meet the demands of high-temperature environments. For example, in applications such as automotive engine compartments and high-temperature pipe insulation, traditional foam materials are prone to softening, deformation, and even melting, resulting in reduced insulation performance and structural integrity, shortening their service life.
[0003] Furthermore, the mechanical properties of traditional polystyrene foam materials need to be improved. Under high temperature conditions, the molecular chains within the material tend to relax and slip, resulting in a significant decrease in strength and modulus, making it unable to withstand high mechanical stress. This performance shortcoming limits its application in high-performance, high-reliability applications.
[0004] In the existing technology, the heat resistance and mechanical properties of polystyrene foam materials are usually improved by adding inorganic fillers (such as talc, calcium carbonate, etc.). However, the addition of these fillers often leads to increased material density, poor processing performance, and limited effect on improving heat resistance.
[0005] Therefore, in order to solve the above problems, the present invention prepares a heat-resistant polystyrene foam material. Summary of the Invention
[0006] The purpose of the present invention is to overcome the defects of the prior art and provide a heat-resistant polystyrene foam material and a preparation method thereof.
[0007] The purpose of the present invention can be achieved through the following technical solutions: A method for preparing a heat-resistant polystyrene foam material comprises the following steps: Step 1: Styrene monomer, initiator, dispersant, water, foaming agent, and modified graphene are mixed and added into a reactor, followed by washing, centrifugation, and drying to obtain expandable polystyrene beads; Step 2: pre-foaming the polystyrene beads at 80-90°C for 1-2 hours and aging them for 10-15 hours to obtain a pre-foamed material; Step 3: Place the pre-foamed material in a mold, increase the temperature to 100-130°C, foam it twice for 2-3 minutes, and cool it down to shape to obtain a polystyrene foam material.
[0008] More optimally, the polystyrene beads include the following components: by weight, 20-30 parts of styrene monomer, 6-8 parts of initiator, 3-4 parts of dispersant, 8-10 parts of water, 1-2 parts of foaming agent, and 10-12 parts of modified graphene.
[0009] More optimally, the preparation process of the modified graphene is: S1: Pentaerythritol, p-hydroxybenzaldehyde, dimethylformamide, and cyclohexane were mixed, p-toluenesulfonic acid was added as a catalyst, the temperature was raised to 120-130°C, the reaction was carried out for 12-13 hours, and after cooling, the mixture was poured into water, stirred, filtered, and recrystallized to obtain an acetal compound; S2: Under a protective atmosphere, 5-chloro-2-nitrobenzoic acid, 5-hexen-1-amine, and dimethyl sulfoxide are mixed and stirred evenly, and a catalyst, N,N'-dicyclohexylcarbodiimide, is added. The temperature is raised to 90-100°C, and the reaction is carried out for 6-8 hours. The mixture is cooled to room temperature, filtered, washed, and dried to obtain an alkenyl compound. S3: Under a protective atmosphere, the alkenyl compound, acetal compound, dimethylformamide, and anhydrous potassium carbonate are mixed, stirred at room temperature for 10-15 minutes, then the temperature is increased to 110-120°C, the reaction is carried out for 12-13 hours, cooled to room temperature, filtered and purified, and then transferred to an ethanol solvent. A palladium catalyst is added, the temperature is increased to 60-70°C, stirred for 20-30 minutes, and then hydrazine hydrate is added. The temperature is continued to be increased to 90-100°C, the reaction is carried out for 7-8 hours, filtered while hot, and post-treated to obtain a modifier; S4: Add the modifier and graphene oxide to N,N-dimethylformamide, stir evenly, add 1-ethyl-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide, increase the temperature to 70-80°C, react for 3-4 hours, cool to room temperature, filter, wash, freeze-dry, and finally add to N,N-dimethylformamide, add sodium borohydride, control the temperature at 0-90°C, stir and reduce for 2-3 hours to obtain modified graphene.
[0010] In the scheme, under the action of the acidic catalyst p-toluenesulfonic acid, the carbonyl oxygen of the aldehyde group contained in p-hydroxybenzaldehyde is protonated, increasing the electrophilicity of the aldehyde group. Then, the hydroxyl group of pentaerythritol acts as a nucleophilic reagent to attack the aldehyde group, resulting in a nucleophilic addition reaction to generate a hemiacetal intermediate. Subsequently, the hemiacetal intermediate is dehydrated to form a stable acetal compound.
[0011] In the scheme, the carboxyl group of 5-chloro-2-nitrobenzoic acid is activated by N,N'-dicyclohexylcarbodiimide (DCC), and then undergoes a nucleophilic addition reaction with the amino group of 5-hexen-1-amine to obtain an alkenyl compound.
[0012] In the scheme, the phenolic hydroxyl group in the acetal compound is deprotonated under the action of anhydrous potassium carbonate to generate a phenol oxide anion, and the chlorine atom in the alkenyl compound is a good leaving group; the phenol oxide anion acts as a nucleophile, attacking the carbon atom in the alkenyl compound, replacing the chlorine atom, and then under the action of the reducing agent hydrazine hydrate, the nitro group is reduced to an amino group to obtain a modifier.
[0013] More optimally, the acetal compound raw material includes the following components: by weight, 3-4 parts of pentaerythritol, 6-8 parts of p-hydroxybenzaldehyde, 50-55 parts of dimethylformamide, 12-18 parts of cyclohexane, and 0.1-0.2 parts of p-toluenesulfonic acid.
[0014] More optimally, the alkenyl compound raw material includes the following components: by weight, 4-5 parts of 5-chloro-2-nitrobenzoic acid, 2-3 parts of 5-hexen-1-amine, 60-70 parts of dimethyl sulfoxide, and 0.1-0.2 parts of N,N'-dicyclohexylcarbodiimide.
[0015] More optimally, the modifier raw material includes the following components: by weight, 5-6 parts of alkenyl compound, 2-3 parts of acetal compound, 50-60 parts of dimethylformamide, 1-2 parts of anhydrous potassium carbonate, 60-70 parts of ethanol solvent, 0.1-0.2 parts of palladium catalyst, and 20-22 parts of hydrazine hydrate.
[0016] More optimally, the modified graphene raw material includes the following components: by weight, 10-12 parts of modifier, 3-4 parts of graphene oxide, 50-55 parts of N,N-dimethylformamide, 0.1-0.2 parts of 1-ethyl-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, 0.1-0.2 parts of N-hydroxysuccinimide, 70-80 parts of N,N-dimethylformamide, and 3-4 parts of sodium borohydride.
[0017] Beneficial effects of the present invention: The present invention modifies graphene oxide by synthesizing a modifier with an acetal spiro ring structure, and introduces double bonds to copolymerize it with styrene monomer, thereby improving the heat resistance and mechanical properties of the resulting polystyrene foam material. The details are as follows: First, the acetal spiro ring structure is a relatively stable chemical structure, and its ring structure has high thermal and chemical stability. Under high temperature conditions, the acetal spiro ring structure can effectively resist thermal decomposition, thereby providing additional thermal stability to the material. Second, during the copolymerization process, modified graphene can act as a nucleating agent, effectively promoting the crystallization process of polystyrene, thereby significantly improving its crystallinity. The increased crystallinity makes it more difficult for the polystyrene molecular chains to slip and depolymerize at high temperatures, thereby enhancing the material's heat resistance. At the same time, strong intermolecular forces are formed between the evenly dispersed modified graphene and the polystyrene matrix. This enhanced interaction further restricts the movement of the molecular chains and improves the material's thermal stability in high-temperature environments. In addition, the rigidity of the acetal spirocyclic structure in the modified graphene also provides additional thermal stability to the material, further optimizing the heat resistance and mechanical strength of the polystyrene foam. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The present invention will be further described below with reference to the accompanying drawings.
[0019] Figure 1 This is the synthesis process of the alkenyl compound in the modified graphene preparation process of Example 1, Example 2, and Example 3; Figure 2 This is the synthesis process of the modifier in the modified graphene preparation process of Example 1, Example 2, and Example 3. DETAILED DESCRIPTION
[0020] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.
[0021] Example 1: A method for preparing a heat-resistant polystyrene foam material, comprising the following steps: Step 1: 20 parts of styrene monomer, 6 parts of initiator, 3 parts of dispersant, 8 parts of water, 1 part of foaming agent, and 10 parts of modified graphene are mixed and added into a reactor, washed, centrifuged, and dried to obtain expandable polystyrene beads; Step 2: pre-foaming the polystyrene beads at 80° C. for 1 hour and aging them for 10 hours to obtain a pre-foamed material; Step 3: Place the pre-foamed material in a mold, raise the temperature to 100°C, perform secondary foaming for 2 minutes, and cool and shape to obtain a polystyrene foam material; Wherein, the preparation process of modified graphene is: S1: Mix 3 parts of pentaerythritol, 6 parts of p-hydroxybenzaldehyde, 50 parts of dimethylformamide, and 12 parts of cyclohexane, add 0.1 parts of p-toluenesulfonic acid as a catalyst, raise the temperature to 120°C, react for 12 hours, cool, pour into water, stir, filter, and recrystallize to obtain an acetal compound; S2: Under protective atmosphere, 4 parts of 5-chloro-2-nitrobenzoic acid, 2 parts of 5-hexen-1-amine, and 60 parts of dimethyl sulfoxide were mixed and stirred evenly, and 0.1 parts of N,N'-dicyclohexylcarbodiimide as a catalyst was added. The temperature was raised to 90°C, and the reaction was carried out for 6 hours. The reaction was cooled to room temperature, filtered, washed, and dried to obtain an alkenyl compound (such as Figure 1 shown); S3: Under a protective atmosphere, 5 parts of an olefin compound, 2 parts of an acetal compound, 50 parts of dimethylformamide, and 1 part of anhydrous potassium carbonate were mixed and stirred at room temperature for 10 minutes. The mixture was then heated to 110°C and reacted for 12 hours. The mixture was cooled to room temperature, filtered and purified, and then transferred to 60 parts of an ethanol solvent. 0.1 parts of a palladium catalyst was added, the temperature was raised to 60°C, stirred for 20 minutes, and then 20 parts of hydrazine hydrate were added. The temperature was further raised to 90°C, the reaction was continued for 7 hours, filtered while hot, and post-treated to obtain a modifier (such as Figure 2 shown); S4: Add 10 parts of modifier and 3 parts of graphene oxide to 50 parts of N,N-dimethylformamide, stir evenly, add 0.1 parts of 1-ethyl-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 0.1 parts of N-hydroxysuccinimide, raise the temperature to 70°C, react for 3 hours, cool to room temperature, filter, wash, freeze-dry, and finally add to 70 parts of N,N-dimethylformamide, add 3 parts of sodium borohydride, control the temperature at 80°C, stir and reduce for 2 hours to obtain modified graphene.
[0022] Example 2: A method for preparing a heat-resistant polystyrene foam material, comprising the following steps: Step 1: 30 parts of styrene monomer, 8 parts of initiator, 4 parts of dispersant, 10 parts of water, 2 parts of foaming agent, and 12 parts of modified graphene are mixed and added into a reactor, washed, centrifuged and dried to obtain expandable polystyrene beads; Step 2: pre-foaming the polystyrene beads at 90° C. for 2 hours and aging them for 15 hours to obtain a pre-foamed material; Step 3: Place the pre-foamed material in a mold, raise the temperature to 130°C, perform secondary foaming for 3 minutes, and cool and shape to obtain a polystyrene foam material; Wherein, the preparation process of modified graphene is: S1: 4 parts of pentaerythritol, 8 parts of p-hydroxybenzaldehyde, 55 parts of dimethylformamide, and 18 parts of cyclohexane were mixed, and 0.2 parts of p-toluenesulfonic acid as a catalyst were added. The temperature was raised to 130°C, and the reaction was carried out for 13 hours. After cooling, the mixture was poured into water, stirred, filtered, and recrystallized to obtain an acetal compound. S2: Under protective atmosphere, 5 parts of 5-chloro-2-nitrobenzoic acid, 3 parts of 5-hexen-1-amine, and 70 parts of dimethyl sulfoxide were mixed and stirred evenly, and 0.2 parts of N,N'-dicyclohexylcarbodiimide as a catalyst were added. The temperature was raised to 100°C, and the reaction was carried out for 8 hours. The mixture was cooled to room temperature, filtered, washed, and dried to obtain an alkenyl compound (such as Figure 1 shown); S3: Under a protective atmosphere, 6 parts of an olefin compound, 3 parts of an acetal compound, 60 parts of dimethylformamide, and 2 parts of anhydrous potassium carbonate were mixed and stirred at room temperature for 15 minutes. The mixture was then heated to 120°C and reacted for 13 hours. The mixture was cooled to room temperature, filtered and purified, and then transferred to 70 parts of an ethanol solvent. 0.2 parts of a palladium catalyst was added, the temperature was raised to 70°C, and the mixture was stirred for 30 minutes. 22 parts of hydrazine hydrate were then added, the temperature was continued to be raised to 100°C, and the mixture was reacted for 8 hours. The mixture was filtered while hot and post-treated to obtain a modifier (such as Figure 2 shown); S4: Add 12 parts of modifier and 4 parts of graphene oxide to 55 parts of N,N-dimethylformamide, stir evenly, add 0.2 parts of 1-ethyl-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 0.2 parts of N-hydroxysuccinimide, increase the temperature to 80°C, react for 4 hours, cool to room temperature, filter, wash, freeze-dry, and finally add to 80 parts of N,N-dimethylformamide, add 4 parts of sodium borohydride, control the temperature at 90°C, stir and reduce for 3 hours to obtain modified graphene.
[0023] Example 3: A method for preparing a heat-resistant polystyrene foam material, comprising the following steps: Step 1: 25 parts of styrene monomer, 7 parts of initiator, 3.5 parts of dispersant, 9 parts of water, 1.5 parts of foaming agent, and 11 parts of modified graphene are mixed and added into a reactor, washed, centrifuged, and dried to obtain expandable polystyrene beads; Step 2: pre-foaming the polystyrene beads at 85° C. for 1.5 hours and aging them for 12.5 hours to obtain a pre-foamed material; Step 3: Place the pre-foamed material in a mold, raise the temperature to 115°C, perform secondary foaming for 2.5 minutes, and cool and shape to obtain a polystyrene foam material; Wherein, the preparation process of modified graphene is: S1: 3.5 parts of pentaerythritol, 7 parts of p-hydroxybenzaldehyde, 52.5 parts of dimethylformamide, and 15 parts of cyclohexane were mixed, and 0.15 parts of p-toluenesulfonic acid as a catalyst were added. The temperature was raised to 125°C, and the reaction was carried out for 12.5 hours. After cooling, the mixture was poured into water, stirred, filtered, and recrystallized to obtain an acetal compound. S2: Under protective atmosphere, 4.5 parts of 5-chloro-2-nitrobenzoic acid, 2.5 parts of 5-hexen-1-amine, and 65 parts of dimethyl sulfoxide were mixed and stirred evenly, and 0.15 parts of N,N'-dicyclohexylcarbodiimide as a catalyst was added, and the temperature was raised to 95°C, and the reaction was carried out for 7 hours. The reaction was cooled to room temperature, filtered, washed, and dried to obtain an alkenyl compound (such as Figure 1 shown); S3: Under a protective atmosphere, 5.5 parts of an olefin compound, 2.5 parts of an acetal compound, 55 parts of dimethylformamide, and 1.5 parts of anhydrous potassium carbonate were mixed and stirred at room temperature for 12.5 min. The mixture was then heated to 115°C and reacted for 12.5 h. The mixture was cooled to room temperature, filtered and purified, and then transferred to 65 parts of an ethanol solvent. 0.15 parts of a palladium catalyst was added, the temperature was raised to 65°C, stirred for 25 min, and then 21 parts of hydrazine hydrate were added. The temperature was further raised to 95°C, the reaction was continued for 7.5 h, filtered while hot, and post-treated to obtain a modifier (such as Figure 2 shown); S4: Add 11 parts of modifier and 3.5 parts of graphene oxide to 52.5 parts of N,N-dimethylformamide, stir evenly, add 0.15 parts of 1-ethyl-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 0.15 parts of N-hydroxysuccinimide, raise the temperature to 75°C, react for 3.5 hours, cool to room temperature, filter, wash, freeze-dry, and finally add to 75 parts of N,N-dimethylformamide, add 3.5 parts of sodium borohydride, control the temperature at 85°C, stir and reduce for 2.5 hours to obtain modified graphene.
[0024] Comparative Example 1: No modified graphene was added, and the rest was the same as in Example 3, specifically as follows: Step 1: 25 parts of styrene monomer, 7 parts of initiator, 3.5 parts of dispersant, 9 parts of water, and 1.5 parts of foaming agent were mixed and added into a reactor, washed, centrifuged, and dried to obtain expandable polystyrene beads; Step 2: pre-foaming the polystyrene beads at 85° C. for 1.5 hours and aging them for 12.5 hours to obtain a pre-foamed material; Step 3: Place the pre-foamed material in a mold, increase the temperature to 115°C, foam it twice for 2.5 minutes, and cool and shape it to obtain a polystyrene foam material.
[0025] Comparative Example 2: The graphene surface was modified using a silane coupling agent (vinyltrimethoxysilane). The rest was the same as in Example 3, as follows: Step 1: 25 parts of styrene monomer, 7 parts of initiator, 3.5 parts of dispersant, 9 parts of water, 1.5 parts of foaming agent, and 11 parts of modified graphene are mixed and added into a reactor, washed, centrifuged, and dried to obtain expandable polystyrene beads; Step 2: pre-foaming the polystyrene beads at 85° C. for 1.5 hours and aging them for 12.5 hours to obtain a pre-foamed material; Step 3: Place the pre-foamed material in a mold, raise the temperature to 115°C, perform secondary foaming for 2.5 minutes, and cool and shape to obtain a polystyrene foam material; Among them, the preparation process of modified graphene is: adding graphite oxide and vinyltrimethoxysilane in a mass ratio of 1:5 to ethanol, controlling the temperature at 90°C, stirring and reacting for 4 hours to obtain graphene oxide grafted with a silane coupling agent, and then transferring it to ethyl acetate, adding sodium borohydride, controlling the temperature at 90°C, stirring and reducing the reaction for 2 hours to obtain modified graphene.
[0026] Testing: (1) The polystyrene foam materials obtained in the examples and comparative examples were subjected to heat resistance testing according to standard GB-1035; (2) The polystyrene foam materials obtained in the examples and comparative examples were subjected to impact strength testing according to GJB1585A-2004, with the sample size being 120 mm × 15 mm × 10 mm. The obtained data are shown in the following table: Table 1
[0027] Conclusion: The present invention modifies graphene oxide by synthesizing a modifier with an acetal spiro ring structure and introduces it into a polystyrene foam material, significantly improving the heat resistance and mechanical properties of the material. Experimental results show that the heat resistance temperatures of the polystyrene foam materials with modified graphene in Examples 1, 2, and 3 reach 110°C, 115°C, and 118°C, respectively, which are much higher than the 90°C of Comparative Example 1 (no modified graphene added) and 93°C of Comparative Example 2 (graphene modified with a silane coupling agent). In terms of impact strength, the impact strength of Examples 1, 2, and 3 are 0.42 kJ.m -2 、0.43KJ.m -2 and 0.45KJ.m -2 , which is significantly better than the 0.31KJ.m -2 and 0.38KJ.m in Comparative Example 2 -2 This shows that the addition of modified graphene effectively enhances the heat resistance and impact strength of polystyrene foam materials, significantly improving their application performance in high-temperature environments.
[0028] Throughout the specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
[0029] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in similar ways. As long as they do not deviate from the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.
Claims
1. A method for preparing a heat-resistant polystyrene foam material, characterized in that: The following steps are involved: Step 1: Styrene monomer, initiator, dispersant, water, foaming agent, and modified graphene are mixed and added into a reactor, followed by washing, centrifugation, and drying to obtain expandable polystyrene beads; Step 2: pre-foaming the polystyrene beads at 80-90°C for 1-2 hours and aging them for 10-15 hours to obtain a pre-foamed material; Step 3: Place the pre-foamed material in a mold, increase the temperature to 100-130°C, foam it twice for 2-3 minutes, and cool it down to shape to obtain a polystyrene foam material.
2. The method for preparing a heat-resistant polystyrene foam material according to claim 1, wherein: The polystyrene beads include the following components: by weight, 20-30 parts of styrene monomer, 6-8 parts of initiator, 3-4 parts of dispersant, 8-10 parts of water, 1-2 parts of foaming agent, and 10-12 parts of modified graphene.
3. The method for preparing a heat-resistant polystyrene foam material according to claim 2, wherein: The preparation process of the modified graphene is: S1: Pentaerythritol, p-hydroxybenzaldehyde, dimethylformamide, and cyclohexane were mixed, p-toluenesulfonic acid was added as a catalyst, the temperature was raised to 120-130°C, the reaction was carried out for 12-13 hours, and after cooling, the mixture was poured into water, stirred, filtered, and recrystallized to obtain an acetal compound; S2: Under a protective atmosphere, 5-chloro-2-nitrobenzoic acid, 5-hexen-1-amine, and dimethyl sulfoxide are mixed and stirred evenly, and a catalyst, N,N'-dicyclohexylcarbodiimide, is added. The temperature is raised to 90-100°C, and the reaction is carried out for 6-8 hours. The mixture is cooled to room temperature, filtered, washed, and dried to obtain an alkenyl compound. S3: Under a protective atmosphere, the alkenyl compound, acetal compound, dimethylformamide, and anhydrous potassium carbonate are mixed, stirred at room temperature for 10-15 minutes, then the temperature is increased to 110-120°C, the reaction is carried out for 12-13 hours, cooled to room temperature, filtered and purified, and then transferred to an ethanol solvent. A palladium catalyst is added, the temperature is increased to 60-70°C, stirred for 20-30 minutes, and then hydrazine hydrate is added. The temperature is continued to be increased to 90-100°C, the reaction is carried out for 7-8 hours, filtered while hot, and post-treated to obtain a modifier; S4: Add the modifier and graphene oxide to N,N-dimethylformamide, stir evenly, add 1-ethyl-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide, increase the temperature to 70-80°C, react for 3-4 hours, cool to room temperature, filter, wash, freeze-dry, and finally add to N,N-dimethylformamide, add sodium borohydride, control the temperature at 0-90°C, stir and reduce for 2-3 hours to obtain modified graphene.
4. The method for preparing a heat-resistant polystyrene foam material according to claim 3, wherein: The acetal compound raw material comprises the following components: by weight, 3-4 parts of pentaerythritol, 6-8 parts of p-hydroxybenzaldehyde, 50-55 parts of dimethylformamide, 12-18 parts of cyclohexane, and 0.1-0.2 parts of p-toluenesulfonic acid.
5. The method for preparing a heat-resistant polystyrene foam material according to claim 3, wherein: The alkenyl compound raw material comprises the following components: by weight, 4-5 parts of 5-chloro-2-nitrobenzoic acid, 2-3 parts of 5-hexen-1-amine, 60-70 parts of dimethyl sulfoxide, and 0.1-0.2 parts of N,N'-dicyclohexylcarbodiimide.
6. The method for preparing a heat-resistant polystyrene foam material according to claim 3, wherein: The modifier raw material comprises the following components: by weight, 5-6 parts of an alkenyl compound, 2-3 parts of an acetal compound, 50-60 parts of dimethylformamide, 1-2 parts of anhydrous potassium carbonate, 60-70 parts of an ethanol solvent, 0.1-0.2 parts of a palladium catalyst, and 20-22 parts of hydrazine hydrate.
7. The method for preparing a heat-resistant polystyrene foam material according to claim 3, wherein: The modified graphene raw material includes the following components: by weight, 10-12 parts of a modifier, 3-4 parts of graphene oxide, 50-55 parts of N,N-dimethylformamide, 0.1-0.2 parts of 1-ethyl-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, 0.1-0.2 parts of N-hydroxysuccinimide, 70-80 parts of N,N-dimethylformamide, and 3-4 parts of sodium borohydride.
8. The polystyrene foam material obtained by the method for preparing a heat-resistant polystyrene foam material according to any one of claims 1 to 7.