A kind of ultra-low thermal conductivity polystyrene modified by silica aerogel and preparation method thereof

Abstract

The invention discloses a silica aerogel-modified ultra-low thermal conductive polystyrene and a preparation method thereof, belonging to the technical field of polymer materials. The technical scheme thereof is as follows: raw materials used for the polystyrene include the following components in parts by weight: 30-40 parts of styrene, 2.5-5.5 parts of silica aerogel powder, 4-8 parts of graphene oxide, 1.2-1.5 parts of divinylbenzene, 0.04-0.05 parts of polyethylene wax, 0.5-1.5 parts of dispersant, 0.5-2 parts of polyvinyl alcohol, 0.2-0.7 parts of tricalcium phosphate, 0.4-0.8 parts of organic peroxide, 2-3 parts of pentane, 0.2-0.4 parts of tributyl phosphate and 50-70 parts of water, so as to ensure that the polystyrene material has a low thermal conductivity and flame retardant performance at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a silica aerogel-modified ultra-low thermal conductivity polystyrene and a preparation method thereof. Background Art

[0002] Polystyrene foam is often used as daily necessities such as building insulation boards, lunch boxes, and packaging bags due to its light weight and low cost. In recent years, with the rapid development of the industry, market demand has become increasingly diversified, and the application areas have also been expanded. Traditional polystyrene foam has gradually failed to meet people’s production and life needs. It has become a development trend to combine inorganic particles with specific functions with a polystyrene matrix to prepare polystyrene composite foam materials.

[0003] Since polystyrene itself is not only very easy to burn, but also emits a large amount of toxic smoke when burning, it poses a great threat to public safety and life and property. In addition, polystyrene foam has a huge specific surface area and a honeycomb internal structure, so its combustion spreads extremely fiercely and rapidly. Therefore, in practical applications, flame retardant modification of polystyrene foam is a research hotspot in this field.

[0004] The current industrial method for producing flame-retardant polystyrene foam is to load the flame retardant onto the surface of polystyrene foam particles through a binder to form a flame-retardant coating. If the amount of flame-retardant coating added is small, the flame retardant efficiency is low, and if more flame-retardant coating components are added, the polystyrene foam will have a higher thermal conductivity, affecting the thermal insulation performance. Summary of the invention

[0005] In order to ensure that the polystyrene material has low thermal conductivity and flame retardant properties, the present invention provides a silica aerogel-modified ultra-low thermal conductivity polystyrene and a preparation method thereof.

[0006] The first object of the present invention is to provide an ultra-low thermal conductivity polystyrene modified with silica aerogel, using the following technical solution:

[0007] Disclosed is a silica aerogel-modified ultra-low thermal conductive polystyrene. The raw materials used for the polystyrene include the following components in parts by weight: 30-40 parts of styrene, 2.5-5.5 parts of silica aerogel powder, 4-8 parts of graphene oxide, 1.2-1.5 parts of divinylbenzene, 0.04-0.05 parts of polyethylene wax, 0.5-1.5 parts of dispersant, 0.5-2 parts of polyvinyl alcohol, 0.2-0.7 parts of tricalcium phosphate, 0.4-0.8 parts of organic peroxide, 2-3 parts of pentane, 0.2-0.4 parts of tributyl phosphate and 50-70 parts of water.

[0008] Preferably, the silica aerogel powder is silica aerogel powder modified with a silane coupling agent, and the modification method comprises the following steps: adding silica aerogel powder and ammonia water in a weight ratio of 10: (20-40): 500 to anhydrous ethanol, stirring evenly, then adding the silane coupling agent, ultrasonically dispersing evenly, reacting in a closed state for 40-50 hours, and then heating in an open state in a water bath at 60-80°C for 1.5-2.5 hours, and then centrifuging, washing, and drying to obtain the modified silica aerogel powder.

[0009] Preferably, the amount of the silane coupling agent added is 3-7% by weight of the silica aerogel powder.

[0010] Preferably, the silane coupling agent is a vinyl coupling agent.

[0011] Preferably, the drying temperature is 60-80°C.

[0012] Preferably, the graphene oxide is graphene oxide modified with polyacrylonitrile, and the modification method comprises the following steps: adding graphene oxide and polyacrylonitrile in a weight ratio of (1-3):1 to ethanol, uniformly dispersing by ultrasonic stirring, stirring and reacting for 1.5-2.5h, adding hydrazine hydrate and ammonia water to the reaction system, starting to heat up, and reacting for 12h after the system temperature reaches 90-95°C, and then decompressing and filtering the product, washing, drying and grinding to obtain the modified graphene oxide powder.

[0013] Preferably, the organic peroxide comprises benzoyl peroxide, dicumyl peroxide and tert-butyl perbenzoate in a weight ratio of 1:1:1.

[0014] Preferably, the dispersant is sodium dodecyl sulfate.

[0015] The second object of the present invention is to provide a method for preparing the above-mentioned silica aerogel-modified ultra-low thermal conductive polystyrene, comprising the following preparation steps:

[0016] S1, adding tricalcium phosphate, dispersant and polyvinyl alcohol into water and stirring to disperse to obtain an aqueous solution;

[0017] S2. Add silica aerogel powder, styrene and polyethylene wax to the aqueous solution and heat it to 50-60°C, then add graphene oxide, divinylbenzene, organic peroxide, pentane and tributyl phosphate and stir evenly, then heat it to 90-95°C and react for 10 hours, then cool and dry the material to obtain ultra-low thermal conductivity polystyrene.

[0018] In summary, the present invention has the following beneficial effects:

[0019] 1. The present application not only ensures that polystyrene has an ultra-low thermal conductivity coefficient, but also improves the flame retardant and heat insulating properties of polystyrene by adding silica aerogel powder and graphene oxide to styrene.

[0020] 2. After the silica aerogel powder is modified with a silane coupling agent, it reacts with styrene and graphene oxide under the action of an organic peroxide, and a styrene-based polymer is introduced on the surface of the silica aerogel powder particles, and finally the inorganic particles and the organic polymer are compounded in the same particle to obtain a stable polymer core-shell polymer composite material, which effectively improves the thermal insulation performance of the polystyrene foam.

[0021] 3. After graphene oxide is modified with polyacrylonitrile, the dispersion ability of graphene oxide in the system can be effectively improved, making it difficult for graphene oxide particles to form agglomerates. The addition of polyacrylonitrile can combine graphene oxide with polystyrene through chemical bonds, effectively improving the flame retardant properties of polystyrene foam. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below with reference to the embodiments.

[0023] The raw materials used in the preparation examples, embodiments and comparative examples of this application are all commercially available.

[0024] The CAS number of graphene oxide powder is 7440-44-0;

[0025] The silane coupling agent in Preparation Example 1 of the present application uses one of the vinyl coupling agents, specifically vinyl trichlorosilane, vinyl triethoxysilane, and vinyl triacetoxysilane. The effects achieved are basically the same, so one of them is listed in the preparation example.

[0026] Preparation Example 1.1

[0027] The modification method of silica aerogel modified by a silane coupling agent comprises the following steps:

[0028] Silica aerogel powder in a weight ratio of 10:20:500 and ammonia water with a concentration of 25wt% are added to anhydrous ethanol, and then 3% of vinyltriethoxysilane by weight of the silica aerogel powder is added after stirring. After ultrasonic dispersion, the reaction is carried out in a closed state for 40 hours, and then opened and heated in a water bath at 60°C for 2.5 hours, and then centrifuged, washed, and dried at 60°C to obtain the modified silica aerogel powder.

[0029] Preparation Example 1.2

[0030] The modification method of silica aerogel modified by a silane coupling agent comprises the following steps:

[0031] Silica aerogel powder in a weight ratio of 10:30:500 and ammonia water with a concentration of 25wt% are added to anhydrous ethanol, and the mixture is stirred evenly. Then, 5% vinyltriethoxysilane by weight of the silica aerogel powder is added. After ultrasonic dispersion, the mixture is reacted in a closed state for 45 hours, and then heated in an open state in a water bath at 70°C for 2 hours. The mixture is then centrifuged, washed, and dried at 70°C to obtain the modified silica aerogel powder.

[0032] Preparation Example 1.3

[0033] The modification method of silica aerogel modified by a silane coupling agent comprises the following steps:

[0034] Silica aerogel powder in a weight ratio of 10:40:500 and ammonia water with a concentration of 25wt% are added to anhydrous ethanol, and then 7% of vinyltriethoxysilane by weight of the silica aerogel powder is added after stirring. After ultrasonic dispersion, the reaction is carried out in a closed state for 50 hours, and then opened and heated in a water bath at 80°C for 1.5 hours, and then centrifuged, washed, and dried at 80°C to obtain the modified silica aerogel powder.

[0035] Preparation Example 1.4

[0036] The modification method of silica aerogel modified by silane coupling agent is different from that of Preparation Example 1.2 in that an equal amount of γ-(2,3-cyclochloropropyloxy)propyltrimethoxysilane (an epoxy hydrocarbon coupling agent) is used instead of vinyltriethoxysilane, and the rest is the same as Preparation Example 1.2.

[0037] Preparation Example 2.1

[0038] The modification method of polyacrylonitrile-modified graphene oxide comprises the following steps:

[0039] 10 kg of graphene oxide and 10 kg of polyacrylonitrile were added to 100 L of ethanol, and after being dispersed evenly by ultrasonic stirring, the mixture was stirred and reacted for 1.5 h. 1 kg of hydrazine hydrate and 2 L of ammonia water were added to the reaction system, and the temperature was started to rise. After the system temperature reached 90 ° C, the mixture was reacted for 12 h. The product was then filtered under reduced pressure, washed, dried and ground to obtain the modified graphene oxide powder.

[0040] Preparation Example 2.2

[0041] The modification method of polyacrylonitrile-modified graphene oxide comprises the following steps:

[0042] 20 kg of graphene oxide and 10 kg of polyacrylonitrile were added to 100 L of ethanol, and after being dispersed evenly by ultrasonic stirring, the mixture was stirred and reacted for 2 h. 1 kg of hydrazine hydrate and 2 L of ammonia water were added to the reaction system, and the temperature was started to rise. After the system temperature reached 90 ° C, the mixture was reacted for 12 h. The product was then filtered under reduced pressure, washed, dried and ground to obtain the modified graphene oxide powder.

[0043] Preparation Example 2.3

[0044] The modification method of polyacrylonitrile-modified graphene oxide comprises the following steps:

[0045] 30 kg of graphene oxide and 10 kg of polyacrylonitrile were added to 100 L of ethanol, and after being dispersed evenly by ultrasonic stirring, the mixture was stirred and reacted for 2.5 h. 1 kg of hydrazine hydrate and 2 L of ammonia water were added to the reaction system, and the temperature was started to rise. After the system temperature reached 95 ° C, the mixture was reacted for 12 h. The product was then filtered under reduced pressure, washed, dried and ground to obtain the modified graphene oxide powder. Example 1

[0046] A method for preparing ultra-low thermal conductive polystyrene modified with silica aerogel comprises the following preparation steps:

[0047] S1. Add 0.2 kg of tricalcium phosphate, 0.5 kg of dispersant (sodium lauryl sulfate), and 0.5 kg of polyvinyl alcohol into 50 kg of water and stir to disperse to obtain an aqueous solution;

[0048] S2. Add 2.5kg of silica aerogel powder, 30kg of styrene, and 0.04kg of polyethylene wax to the aqueous solution, heat it to 50°C, then add 4kg of graphene oxide, 1.2kg of divinylbenzene, 0.4kg of organic peroxide, 2kg of pentane, and 0.2kg of tributyl phosphate and stir evenly, then heat it to 90°C and react for 10 hours, cool the material and dry it to obtain ultra-low thermal conductivity polystyrene, wherein the organic peroxide includes benzoyl peroxide, diisopropyl peroxide and tert-butyl perbenzoate in a weight ratio of 1:1:1. Example 2

[0049] A method for preparing ultra-low thermal conductive polystyrene modified with silica aerogel comprises the following preparation steps:

[0050] S1. Add 0.5 kg of tricalcium phosphate, 1.0 kg of dispersant (sodium lauryl sulfate), and 1.2 kg of polyvinyl alcohol into 60 kg of water and stir to disperse to obtain an aqueous solution;

[0051] S2. Add 4kg of silica aerogel powder, 35kg of styrene, and 0.04kg of polyethylene wax to the aqueous solution, heat it to 50°C, then add 6kg of graphene oxide, 1.3kg of divinylbenzene, 0.6kg of organic peroxide, 2kg of pentane, and 0.3kg of tributyl phosphate and stir evenly, then heat it to 95°C and react for 10 hours, cool the material and dry it to obtain ultra-low thermal conductivity polystyrene, wherein the organic peroxide includes benzoyl peroxide, diisopropyl peroxide and tert-butyl perbenzoate in a weight ratio of 1:1:1. Example 3

[0052] A method for preparing ultra-low thermal conductive polystyrene modified with silica aerogel comprises the following preparation steps:

[0053] S1. Add 0.7 kg of tricalcium phosphate, 1.5 kg of dispersant (sodium lauryl sulfate), and 2.0 kg of polyvinyl alcohol into 70 kg of water and stir to disperse to obtain an aqueous solution;

[0054] S2. Add 5.5 kg of silica aerogel powder, 40 kg of styrene, and 0.04 kg of polyethylene wax to the aqueous solution, heat it to 60°C, then add 8 kg of graphene oxide, 1.5 kg of divinylbenzene, 0.8 kg of organic peroxide, 3 kg of pentane, and 0.4 kg of tributyl phosphate and stir evenly, then heat it to 95°C and react for 10 hours, cool the material and dry it to obtain ultra-low thermal conductivity polystyrene, wherein the organic peroxide includes benzoyl peroxide, diisopropyl peroxide and tert-butyl perbenzoate in a weight ratio of 1:1:1. Example 4

[0055] A method for preparing ultra-low thermal conductive polystyrene modified with silica aerogel comprises the following preparation steps:

[0056] S1. Add 0.5 kg of tricalcium phosphate, 1.0 kg of dispersant (sodium lauryl sulfate), and 1.2 kg of polyvinyl alcohol into 60 kg of water and stir to disperse to obtain an aqueous solution;

[0057] S2. Add 4 kg of silica aerogel powder obtained in Preparation Example 1.1, 35 kg of styrene, and 0.04 kg of polyethylene wax to the aqueous phase solution, heat it to 50°C, then add 6 kg of graphene oxide, 1.3 kg of divinylbenzene, 0.6 kg of organic peroxide, 2 kg of pentane, and 0.3 kg of tributyl phosphate and stir evenly. Then heat it to 95°C and react for 10 hours. Then cool the material and dry it to obtain ultra-low thermal conductivity polystyrene, wherein the organic peroxide includes benzoyl peroxide, diisopropyl peroxide and tert-butyl perbenzoate in a weight ratio of 1:1:1. Example 5

[0058] A method for preparing ultra-low thermal conductive polystyrene modified with silica aerogel comprises the following preparation steps:

[0059] S1. Add 0.5 kg of tricalcium phosphate, 1.0 kg of dispersant (sodium lauryl sulfate), and 1.2 kg of polyvinyl alcohol into 60 kg of water and stir to disperse to obtain an aqueous solution;

[0060] S2. Add 4 kg of silica aerogel powder obtained in Preparation Example 1.2, 35 kg of styrene, and 0.04 kg of polyethylene wax to the aqueous phase solution, heat it to 50°C, then add 6 kg of graphene oxide, 1.3 kg of divinylbenzene, 0.6 kg of organic peroxide, 2 kg of pentane, and 0.3 kg of tributyl phosphate and stir evenly. Then heat it to 95°C and react for 10 hours. Then cool the material and dry it to obtain ultra-low thermal conductivity polystyrene, wherein the organic peroxide includes benzoyl peroxide, diisopropyl peroxide and tert-butyl perbenzoate in a weight ratio of 1:1:1. Example 6

[0061] A method for preparing ultra-low thermal conductive polystyrene modified with silica aerogel comprises the following preparation steps:

[0062] S1. Add 0.5 kg of tricalcium phosphate, 1.0 kg of dispersant (sodium lauryl sulfate), and 1.2 kg of polyvinyl alcohol into 60 kg of water and stir to disperse to obtain an aqueous solution;

[0063] S2. Add 4 kg of silica aerogel powder obtained in Preparation Example 1.3, 35 kg of styrene, and 0.04 kg of polyethylene wax to the aqueous phase solution, heat it to 50°C, then add 6 kg of graphene oxide, 1.3 kg of divinylbenzene, 0.6 kg of organic peroxide, 2 kg of pentane, and 0.3 kg of tributyl phosphate and stir evenly. Then heat it to 95°C and react for 10 hours. Then cool the material and dry it to obtain ultra-low thermal conductivity polystyrene, wherein the organic peroxide includes benzoyl peroxide, diisopropyl peroxide and tert-butyl perbenzoate in a weight ratio of 1:1:1. Example 7

[0064] A method for preparing ultra-low thermal conductive polystyrene modified with silica aerogel comprises the following preparation steps:

[0065] S1. Add 0.5 kg of tricalcium phosphate, 1.0 kg of dispersant (sodium lauryl sulfate), and 1.2 kg of polyvinyl alcohol into 60 kg of water and stir to disperse to obtain an aqueous solution;

[0066] S2. Add 4 kg of silica aerogel powder obtained in Preparation Example 1.4, 35 kg of styrene, and 0.04 kg of polyethylene wax to the aqueous phase solution, heat it to 50°C, then add 6 kg of graphene oxide, 1.3 kg of divinylbenzene, 0.6 kg of organic peroxide, 2 kg of pentane, and 0.3 kg of tributyl phosphate and stir evenly. Then heat it to 95°C and react for 10 hours. Then cool the material and dry it to obtain ultra-low thermal conductivity polystyrene, wherein the organic peroxide includes benzoyl peroxide, diisopropyl peroxide and tert-butyl perbenzoate in a weight ratio of 1:1:1. Example 8

[0067] A method for preparing ultra-low thermal conductive polystyrene modified with silica aerogel comprises the following preparation steps:

[0068] S1. Add 0.5 kg of tricalcium phosphate, 1.0 kg of dispersant (sodium lauryl sulfate), and 1.2 kg of polyvinyl alcohol into 60 kg of water and stir to disperse to obtain an aqueous solution;

[0069] S2. Add 4kg of silica aerogel powder, 35kg of styrene, and 0.04kg of polyethylene wax to the aqueous solution and heat it to 50°C. Then add 6kg of graphene oxide obtained in Preparation Example 2.1, 1.3kg of divinylbenzene, 0.6kg of organic peroxide, 2kg of pentane, and 0.3kg of tributyl phosphate and stir evenly. Then heat it to 95°C and react for 10 hours. Then cool the material and dry it to obtain ultra-low thermal conductive polystyrene, wherein the organic peroxide includes benzoyl peroxide, diisopropyl peroxide, and tert-butyl perbenzoate in a weight ratio of 1:1:1. Example 9

[0070] A method for preparing ultra-low thermal conductive polystyrene modified with silica aerogel comprises the following preparation steps:

[0071] S1. Add 0.5 kg of tricalcium phosphate, 1.0 kg of dispersant (sodium lauryl sulfate), and 1.2 kg of polyvinyl alcohol into 60 kg of water and stir to disperse to obtain an aqueous solution;

[0072] S2. Add 4kg of silica aerogel powder, 35kg of styrene, and 0.04kg of polyethylene wax to the aqueous solution and heat it to 50°C. Then add 6kg of graphene oxide obtained in Preparation Example 2.2, 1.3kg of divinylbenzene, 0.6kg of organic peroxide, 2kg of pentane, and 0.3kg of tributyl phosphate and stir evenly. Then heat it to 95°C and react for 10 hours. Then cool the material and dry it to obtain ultra-low thermal conductive polystyrene, wherein the organic peroxide includes benzoyl peroxide, diisopropyl peroxide, and tert-butyl perbenzoate in a weight ratio of 1:1:1. Example 10

[0073] A method for preparing ultra-low thermal conductive polystyrene modified with silica aerogel comprises the following preparation steps:

[0074] S1. Add 0.5 kg of tricalcium phosphate, 1.0 kg of dispersant (sodium lauryl sulfate), and 1.2 kg of polyvinyl alcohol into 60 kg of water and stir to disperse to obtain an aqueous solution;

[0075] S2. Add 4kg of silica aerogel powder, 35kg of styrene, and 0.04kg of polyethylene wax to the aqueous solution and heat it to 50°C. Then add 6kg of graphene oxide obtained in Preparation Example 2.3, 1.3kg of divinylbenzene, 0.6kg of organic peroxide, 2kg of pentane, and 0.3kg of tributyl phosphate and stir evenly. Then heat it to 95°C and react for 10 hours. Then cool the material and dry it to obtain ultra-low thermal conductive polystyrene, wherein the organic peroxide includes benzoyl peroxide, diisopropyl peroxide and tert-butyl perbenzoate in a weight ratio of 1:1:1. Embodiment 11

[0076] A method for preparing ultra-low thermal conductive polystyrene modified with silica aerogel comprises the following preparation steps:

[0077] S1. Add 0.5 kg of tricalcium phosphate, 1.0 kg of dispersant (sodium lauryl sulfate), and 1.2 kg of polyvinyl alcohol into 60 kg of water and stir to disperse to obtain an aqueous solution;

[0078] S2. Add 4 kg of silica aerogel powder obtained in Preparation Example 1.2, 35 kg of styrene, and 0.04 kg of polyethylene wax to the aqueous phase solution, heat it to 50°C, then add 6 kg of graphene oxide obtained in Preparation Example 2.2, 1.3 kg of divinylbenzene, 0.6 kg of organic peroxide, 2 kg of pentane, and 0.3 kg of tributyl phosphate, stir evenly, then heat it to 95°C and react for 10 hours, cool the material and dry it to obtain ultra-low thermal conductivity polystyrene, wherein the organic peroxide includes benzoyl peroxide, diisopropyl peroxide and tert-butyl perbenzoate in a weight ratio of 1:1:1.

[0079] Comparative Example 1

[0080] A method for preparing ultra-low thermal conductive polystyrene modified with silica aerogel is different from that in Example 2 in that silica aerogel powder is not added in step S2, and the rest is the same as in Example 2.

[0081] Comparative Example 2

[0082] A method for preparing ultra-low thermal conductive polystyrene modified with silica aerogel is different from that in Example 2 in that graphene oxide is not added in step S2, and the rest is the same as in Example 2.

[0083] Comparative Example 3

[0084] A method for preparing ultra-low thermal conductive polystyrene modified with silica aerogel, which is different from that in Example 2, in step S2: 4kg of silica aerogel powder, 35kg of styrene, 0.04kg of polyethylene wax, 6kg of graphene oxide, 1.3kg of divinylbenzene, 0.6kg of organic peroxide, 2kg of pentane, and 0.3kg of tributyl phosphate are added to an aqueous phase solution and stirred evenly; the temperature is then raised to 95° C. and reacted for 10 hours; the material is cooled and dried to obtain ultra-low thermal conductive polystyrene, wherein the organic peroxide comprises benzoyl peroxide, diisopropylbenzene peroxide, and tert-butyl perbenzoate in a weight ratio of 1:1:1.

[0085] Performance Testing

[0086] The polystyrene particles obtained in the above examples and comparative examples were poured into a mold, and the mold was placed in a flat vulcanizer for compression molding to make a polystyrene foam insulation board, and then its thermal conductivity, combustion grade and oxygen index were tested. The test results are shown in Table 1.

[0087] The thermal conductivity coefficient is tested using the relevant provisions of the national standard "Guarded Hot Plate Method for Determination of Steady-State Thermal Resistance and Related Properties of Insulating Materials".

[0088] Table 1 Test results of polystyrene foam insulation board

[0089] project Thermal conductivity W / m·k Combustion level Oxygen index% Example 1 0.031 B1 32.5 Example 2 0.030 B1 32.8 Example 3 0.030 B1 32.8 Example 4 0.027 B1 33.4 Example 5 0.026 B1 33.9 Example 6 0.026 B1 33.8 Example 7 0.029 B1 32.9 Example 8 0.027 B1 33.4 Example 9 0.026 B1 33.7 Example 10 0.027 B1 33.7 Embodiment 11 0.024 B1 35.1 Comparative Example 1 0.038 Less than B1 29.6 Comparative Example 2 0.035 Less than B1 30.1 Comparative Example 3 0.034 B1 30.6

[0090] From the table above we can see that:

[0091] The thermal conductivity of the polystyrene foam insulation board obtained in Examples 1-3 of the present application is lower than 0.032 W / m·k, the oxygen index is 32%, and the combustion grade reaches B1. It can be seen that the polystyrene foam insulation board obtained in the present application not only has an ultra-low thermal conductivity, but also has good flame retardant properties.

[0092] Compared with Example 2, when the silica aerogel powder of Example 4-6 adopts the silica aerogel powder obtained in Preparation Example 1, the thermal conductivity of the polystyrene foam insulation board obtained in Example 4-6 is lower than that in Example 2, and the oxygen index is higher than that in Example 2. It can be seen that after the silica aerogel powder is modified by vinyl triethoxysilane, the flame retardant properties of the polystyrene foam insulation board can be effectively improved and the thermal conductivity can be reduced.

[0093] Compared with Example 5, when γ-(2,3-epichloropropyloxy)propyltrimethoxysilane (an epoxy hydrocarbon coupling agent) is used instead of vinyltriethoxysilane-modified silica aerogel powder, the thermal conductivity of the polystyrene foam insulation board obtained in Example 7 is increased compared with that in Example 5, and the oxygen index is decreased compared with that in Example 5. It can be seen that the use of vinyltriethoxysilane-modified silica aerogel powder can effectively improve the low thermal conductivity and flame retardant properties of the polystyrene foam insulation board.

[0094] Compared with Example 2, when graphene oxide is modified with polyacrylonitrile, the flame retardant properties of the polystyrene foam insulation boards obtained in Examples 8-10 are improved compared with Example 2, and the thermal conductivity is reduced compared with Example 2.

[0095] Compared with Example 2, after both the silica aerogel powder and the graphene oxide are modified, the oxygen index of the polystyrene foam insulation board obtained in Example 11 is greatly improved compared with that in Example 2, and the thermal conductivity is also greatly reduced compared with that in Example 2. It can be seen that after both the silica aerogel powder and the graphene oxide are modified, the flame retardant properties of the polystyrene foam insulation board can be effectively improved.

[0096] Compared with Example 2, when the raw materials lack silica aerogel powder or graphene oxide, the oxygen index of the polystyrene foam insulation board obtained in Comparative Example 1-2 is reduced and the thermal conductivity is increased. This can further illustrate that the combined use of the components of the present application can make the polystyrene foam insulation board have good flame retardant properties and low thermal conductivity.

[0097] Compared with Example 2, when all the remaining raw materials are directly added to the aqueous solution, the oxygen index and thermal conductivity of the polystyrene foam insulation board obtained in Comparative Example 3 are lower than those in Example 2.

[0098] The embodiments of this specific implementation method are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, all equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A silica aerogel-modified ultra-low thermal conductivity polystyrene, characterized in that: The raw materials used for the polystyrene include the following components in parts by weight: 30-40 parts of styrene, 2.5-5.5 parts of silica aerogel powder, 4-8 parts of graphene oxide, 1.2-1.5 parts of divinylbenzene, 0.04-0.05 parts of polyethylene wax, 0.5-1.5 parts of dispersant, 0.5-2 parts of polyvinyl alcohol, 0.2-0.7 parts of tricalcium phosphate, 0.4-0.8 parts of organic peroxide, 2-3 parts of pentane, 0.2-0.4 parts of tributyl phosphate, 50 parts of water, 100 parts of water, 20 ...100 parts of water, 100 parts of water, 100 parts of water, 100 parts of water, 100 parts of water, 100 parts of water, 100 parts of water -70 parts, the graphene oxide is graphene oxide modified with polyacrylonitrile, and the modification method comprises the following steps: adding graphene oxide and polyacrylonitrile in a weight ratio of (1-3): 1 to ethanol, dispersing them uniformly with ultrasonic stirring, stirring and reacting for 1.5-2.5 hours, adding hydrazine hydrate and ammonia water to the reaction system, starting to heat up, and reacting for 12 hours after the system temperature reaches 90-95°C, and then decompressing and filtering the product, washing, drying and grinding to obtain the modified graphene oxide powder.

2. The ultra-low thermal conductivity polystyrene modified with silica aerogel according to claim 1, characterized in that: The silica aerogel powder is silica aerogel powder modified by a silane coupling agent, and the modification method comprises the following steps: adding silica aerogel powder and ammonia water in a weight ratio of 10: (20-40): 500 to anhydrous ethanol, stirring evenly, then adding the silane coupling agent, ultrasonically dispersing evenly, reacting in a closed state for 40-50 hours, and then heating in an open state in a water bath at 60-80°C for 1.5-2.5 hours, and then centrifuging, washing, and drying to obtain the modified silica aerogel powder.

3. The ultra-low thermal conductivity polystyrene modified with silica aerogel according to claim 2, characterized in that: The added amount of the silane coupling agent is 3-7% of the weight of the silica aerogel powder.

4. The ultra-low thermal conductivity polystyrene modified with silica aerogel according to claim 2, characterized in that: The silane coupling agent is a vinyl coupling agent.

5. The ultra-low thermal conductivity polystyrene modified with silica aerogel according to claim 2, characterized in that: The drying temperature is 60-80°C.

6. The ultra-low thermal conductivity polystyrene modified with silica aerogel according to claim 1, characterized in that: The organic peroxide comprises benzoyl peroxide, dicumyl peroxide and tert-butyl perbenzoate in a weight ratio of 1:1:

1.

7. The ultra-low thermal conductivity polystyrene modified with silica aerogel according to claim 1, characterized in that: The dispersant is sodium lauryl sulfate.

8. A method for preparing the ultra-low thermal conductive polystyrene modified with silica aerogel according to any one of claims 1 to 7, characterized in that: The method comprises the following preparation steps: S1, adding tricalcium phosphate, dispersant and polyvinyl alcohol into water and stirring to disperse to obtain an aqueous solution; S2. Add silica aerogel powder, styrene and polyethylene wax to the aqueous solution and heat it to 50-60°C, then add graphene oxide, divinylbenzene, organic peroxide, pentane and tributyl phosphate and stir evenly, then heat it to 90-95°C and react for 10 hours, then cool and dry the material to obtain ultra-low thermal conductivity polystyrene.