Low-temperature-resistant polycarbonate and preparation method thereof, and low-temperature-resistant cement aerogel material and preparation method thereof

Abstract

The invention relates to the technical field of material engineering, and particularly discloses low-temperature-resistant polycarbonate and a preparation method thereof as well as a low-temperature-resistant cement aerogel material and a preparation method thereof. According to the low-temperature-resistant polycarbonate, siloxane, phosphate and alkoxy structures are introduced into the structure, so that the glass-transition temperature is reduced, the temperature application range of the material is expanded to-60-70 DEG C, and the low-temperature-resistant polycarbonate has better low-temperature resistance and weather resistance than common resin materials and even polycarbonate. The low-temperature-resistant cement aerogel material can be prepared from the low-temperature-resistant polycarbonate material, and the material adopts low-cost raw materials and a preparation process, has the excellent characteristics of high strength, light weight, nonflammability and the like, and can be used for preparing an explosion-proof tank.

Description

Technical Field

[0001] This application relates to the field of materials engineering technology, and more specifically, it relates to a low-temperature resistant polycarbonate and its preparation method, and a low-temperature resistant cement aerogel material and its preparation method. Background Technology

[0002] With global climate change and the expanding scope of human activities, the performance requirements for building materials in extreme environments are increasing. Traditional cement-based materials are prone to increased brittleness, decreased strength, and freeze-thaw damage in low-temperature environments, severely restricting their application in frigid regions. Aerogel, a novel material with a nanoporous structure, has attracted much attention due to its extremely low density, high specific surface area, and excellent thermal insulation properties. Introducing aerogel into cement-based materials can effectively improve their pore structure, reduce thermal conductivity, and enhance thermal insulation performance. However, ordinary aerogel materials themselves have low strength, high brittleness, and poor interfacial bonding with the cement matrix, making them difficult to directly apply in building engineering.

[0003] In recent years, scholars at home and abroad have conducted a large number of studies on cement aerogel composites, mainly focusing on the following aspects: (1) Selection of aerogel types: Commonly used aerogels include silica aerogel, organic aerogel and carbon aerogel. Among them, silica aerogel is the most widely used because of its wide availability of raw materials and relatively mature preparation process. (2) Aerogel incorporation methods: Mainly include direct incorporation, pre-dispersion and surface modification. Direct incorporation is simple and easy to implement, but aerogel is prone to agglomeration, which affects the material properties; pre-dispersion can improve the dispersibility of aerogel, but the process is complicated; surface modification can improve the interfacial bonding force between aerogel and cement matrix, but the cost is high. (3) Optimization of material properties: By adjusting the aerogel dosage, optimizing the mix ratio, adding admixtures and other methods, the mechanical properties, durability and construction performance of cement aerogel composites can be improved.

[0004] Despite the progress made in the above research, existing cement aerogel materials still have the following problems: (1) Insufficient low-temperature resistance: Ordinary cement aerogel materials still suffer from strength reduction and freeze-thaw damage in low-temperature environments, making it difficult to meet the requirements for use in extremely cold regions. (2) Mechanical properties need to be improved: The introduction of aerogel will reduce the mechanical strength of cement-based materials, requiring further optimization of material proportions and preparation processes. (3) High cost: Aerogel materials are expensive, limiting their large-scale application. Summary of the Invention

[0005] This application provides a low-temperature resistant polycarbonate and its preparation method, as well as a low-temperature resistant cement aerogel material and its preparation method. The low-temperature resistant polycarbonate of this application introduces siloxane, phosphoric acid and alkoxy structures into its structure, thereby lowering the glass transition temperature and expanding the temperature range of the material to -60~70℃. The cement aerogel material using the low-temperature resistant polycarbonate of this application combines excellent properties such as high strength, light weight and non-flammability. When used as a buffer layer in explosion-proof boxes, it can improve the overall performance of explosion-proof boxes.

[0006] In a first aspect, this application provides a low-temperature resistant polycarbonate, employing the following technical solution: A low-temperature resistant polycarbonate, the structure of which is shown in Formula 1: (1) In Equation 1, n is an integer, ranging from 20 to 100, and the weight-average molecular weight of polycarbonate ranges from 20,000 to 500,000; the structure of Q in the structural formula is shown in Equation 2: (2) In Equation 2, the structure of M is shown in Equation 3: (3) In Formula 3, X is methylene or ethoxy, where a, b, and c are independent of each other and are all integers; the value of a ranges from 2 to 6; the value of b ranges from 1 to 10; and the value of c ranges from 10 to 20.

[0007] By adopting the above technical solution, the low-temperature resistant polycarbonate of this application, when incorporated into aerogel, achieves better low-temperature resistance and weather resistance. The improved low-temperature resistance is attributed to the newly introduced siloxane structure in the molecular structure. Compared to ordinary resins, which mostly consist of C-C and CO bonds, the Si–O alternating bonds have high bond energy, good flexibility, and a lower glass transition temperature (Tg), typically below -50℃. This allows it to maintain good elasticity and toughness at low temperatures, avoiding the problems of brittleness and poor impact resistance in resin materials at low temperatures. Therefore, the low-temperature resistant polycarbonate of this application, by introducing siloxane, phosphate, and alkoxy structures into its structure, lowers the glass transition temperature and expands the material's operating temperature range to -60~70℃, exhibiting better low-temperature resistance and weather resistance than ordinary resin materials and even ordinary polycarbonate.

[0008] Secondly, this application provides a method for preparing low-temperature resistant polycarbonate, employing the following technical solution: A method for preparing low-temperature resistant polycarbonate includes the following steps: Preparation of compound 1: The diol initiator and the epoxide were subjected to an ethoxylation reaction to obtain compound 1; Preparation of compound 2: Compound 1 and a phosphorylating agent were subjected to a phosphorylation reaction to obtain compound 2; Preparation of compound 3: Compound 2 and silane coupling agent KH560 were reacted at 60-80℃ for 1-2 hours to obtain compound 3; Preparation of polycarbonate: Under a nitrogen atmosphere, bisphenol A, compound 3, diester and catalyst are subjected to transesterification reaction, followed by polycondensation reaction to obtain polycarbonate.

[0009] Furthermore, in the preparation step of compound 1, the epoxide includes propylene oxide and ethylene oxide, and the molar ratio of the initiator, propylene oxide and ethylene oxide is 1:(1-10):(10-20).

[0010] Furthermore, in the preparation step of compound 1, the initiator includes at least one selected from ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, and triethylene glycol. The reaction raw materials also include a catalyst, which is a base catalyst, including but not limited to one selected from potassium, sodium, potassium methoxide, sodium methoxide, potassium ethoxide, sodium ethoxide, potassium hydroxide, sodium hydroxide, potassium hydride, and sodium hydride. The molar ratio of initiator to catalyst is 1:(0.001-0.1). The reaction temperature is 110-150℃, the reaction pressure is controlled at -0.10~+0.50MPa, and the reaction time is 1-10h.

[0011] Furthermore, in the preparation step of compound 2, the molar ratio of phosphorylating agent to compound is 1:(2-2.4), wherein the phosphorylating agent is converted to an equimolar amount of phosphoric acid.

[0012] Furthermore, in the preparation step of compound 2, a certain amount of compound 1 is first placed in a reaction vessel, and a phosphorylation reagent is added in batches under a low-temperature cooling environment; then the temperature is raised to a set temperature and the reaction continues for a certain period of time. The phosphorylation reagent includes 85% phosphoric acid, phosphorus pentoxide, polyphosphoric acid, solid phosphoric acid, and any combination thereof in proportion. The phosphorylation reagent is used by batch feeding, with the feeding frequency controlled at 5-10 g / 10-15 min, and the system temperature not exceeding 60℃. The phosphorylation reaction temperature is 90-110℃, and the reaction time is 5-8 h.

[0013] Furthermore, in the preparation step of compound 3, the molar ratio of compound 2 to silane coupling agent KH560 is (1.02-1.20):1.

[0014] Furthermore, in the preparation step of compound 3, compound 2 is placed in a reaction vessel and heated to 60-80°C until it is completely melted, and then KH560 is added dropwise over a period of 1-2 hours.

[0015] Furthermore, in the preparation step of the polycarbonate, the molar ratio of bisphenol A, compound 4 and diester is (3-5):1:(4-6).

[0016] Furthermore, in the preparation steps of the polycarbonate, an ester exchange reaction is first carried out at a temperature of 120-150℃ for 1-2 hours; then the temperature is further increased to 200-240℃ and the pressure to 150-250Pa to carry out a polycondensation reaction for 2-4 hours.

[0017] Furthermore, in the preparation step of the polycarbonate, the pressure is 50-100 Pa under a nitrogen atmosphere. The catalyst is one of sodium methoxide, sodium tert-butoxide, sodium tetraborate, lithium chloride, sodium sulfite, cesium carbonate, zinc acetate, lithium carbonate, tetrabutyl titanate, propyl titanate, isopropyl titanate, and propylene titanate. The amount of catalyst used is 2%-15% of the molar sum of bisphenol A, compound 4, and the diester. The diester is at least one of diphenyl carbonate, dimethyl carbonate, dimethyl dicarbonate, dimethyl terephthalate, diethyl carbonate, diphenyl phthalate, and dibutyl carbonate.

[0018] Furthermore, the molecular weight of the new polycarbonate is 20,000-100,000.

[0019] Thirdly, this application provides a low-temperature resistant cement aerogel material, which adopts the following technical solution: A low-temperature resistant cement aerogel material, the raw materials of which include cement, water, binder, dispersant, low-temperature resistant component, reinforcing fiber and foaming component, wherein the low-temperature resistant component is polycarbonate; the mass ratio of cement, dispersant, low-temperature resistant component, reinforcing fiber and foaming component, binder and water is 1: (0.001-0.05): (0.02-0.05): (0.1-0.2): (0.25-0.5): (0.002-0.005): (0.2-0.5).

[0020] Furthermore, the low-temperature resistant component is polycarbonate powder with a particle size of 10-300 μm.

[0021] Furthermore, the reinforcing fiber is at least one of carbon fiber, glass fiber and polymer fiber, and the length of the reinforcing fiber is 1~10 mm and the diameter is 10~20 μm.

[0022] Furthermore, the foaming component is one of the following: sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, ammonium carbonate, ammonium nitrate, ammonium phosphate, monohydrogen phosphate, dihydrogen phosphate, ammonium nitrite, hydrogen peroxide, azobisisobutyronitrile, azobisisovalerate, azobisisoheptanenitrile, azoisobutyronitrile formamide, azobisisobutyramidine hydrochloride, azobisisobutyronitrile acid, etc.

[0023] Furthermore, the adhesives include polyacrylic acid, polymethacrylic acid, polyacrylate, polymethacrylate, polyethylene glycol, polypropylene glycol, polyacrylamide, polymethacrylamide, polyurethane, polyvinyl alcohol, etc.

[0024] Furthermore, the dispersant is a sulfonate superplasticizer, a naphthalene-based superplasticizer, a polycarboxylate superplasticizer, a phosphate-based superplasticizer, etc.; the cement is sulfoaluminate cement or a mixture of sulfoaluminate cement and silicate cement, wherein when a mixture of sulfoaluminate cement and silicate cement is used, the mass ratio of sulfoaluminate cement to silicate cement is (60-100):(40-10).

[0025] Fourthly, this application provides a method for preparing a low-temperature resistant cement aerogel material, employing the following technical solution: A method for preparing a low-temperature resistant cement aerogel material includes the following steps: Dissolve the adhesive in water, cool the solution to room temperature, then add the dispersant and cement in sequence and stir until homogeneous; then add the low-temperature resistant component, reinforcing fiber and foaming component in sequence and stir until homogeneous. The above solution was frozen using liquid nitrogen at a temperature of -100 to -200°C for 30 to 90 minutes, and then allowed to return to room temperature. It was then dried at a temperature of 40 to 90°C for 12 to 72 hours. After drying, cement aerogel material was obtained.

[0026] In summary, this application has the following beneficial effects: (1) The novel polycarbonate structure used in the low-temperature resistant cement aerogel material disclosed in this invention contains siloxane segments, which have better low-temperature resistance and weather resistance than ordinary resin materials or even polycarbonate.

[0027] (2) The low-temperature resistant cement aerogel material disclosed in this invention can significantly improve the impact resistance of the material at low temperatures.

[0028] (3) The low-temperature resistant cement aerogel material disclosed in this invention uses low-cost raw materials and preparation process, which reduces material costs and is conducive to large-scale promotion and application.

[0029] (4) The glass transition temperature of the novel polycarbonate structural material molecules in the low-temperature resistant cement aerogel material disclosed in this invention is reduced, which expands the temperature range of the material to -60~70℃; it expands the application of the material as an explosion-proof material and can meet the requirements of the low-temperature outdoor explosion-proof box. Detailed Implementation

[0030] The present application will be further described in detail below with reference to the embodiments.

[0031] Preparation Example The preparation example of this application first provides a method for preparing compound 1, including the following steps: Ethoxylation reaction of initiator diol with epoxide: A certain amount of initiator and catalyst are added to the reactor, and the reactor is purged with vacuum and nitrogen gas at least 3 times, each operation lasting at least 5 minutes; then the temperature is raised to the set temperature, and a set mass of epoxide is introduced to carry out the ethoxylation reaction. The reaction temperature is 110-150℃, the reaction pressure is controlled at -0.10~+0.50MPa, and the reaction time is 1-10h.

[0032] The initiator includes at least one selected from ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, and triethylene glycol. The catalyst is a base catalyst, including but not limited to one selected from potassium, sodium, potassium methoxide, sodium methoxide, potassium ethoxide, sodium ethoxide, potassium hydroxide, sodium hydroxide, potassium hydride, and sodium hydride. The epoxide compound is a mixture of propylene oxide and ethylene oxide.

[0033] The molar ratio of initiator, propylene oxide and ethylene oxide, and catalyst is 1:(1-10):(10-20):(0.001-0.1).

[0034] The preparation examples of this application also provide a method for preparing compound 2, comprising the following steps: The compound 1 was subjected to a phosphorylation reaction with a phosphorylating agent: a certain amount of the compound was placed in a reaction vessel, and the phosphorylating agent was added in batches under low-temperature cooling; the temperature was then raised to a set temperature and the reaction continued for a certain period of time. Specifically, the phosphorylating agent was added in batches, with the addition frequency controlled at 5-10 g / 10-15 min, and the system temperature did not exceed 60℃. The phosphorylation reaction temperature was 90-110℃, and the reaction time was 5-8 h.

[0035] The phosphorylation reagent includes 85% phosphoric acid, phosphorus pentoxide, polyphosphoric acid, solid phosphoric acid, and any combination thereof. The molar ratio of the phosphorylation reagent to the compound is 1:(2-2.4), and the phosphorylation reagent is converted to an equimolar amount of phosphoric acid.

[0036] The preparation method of compound 3 provided in this application includes the following steps: A certain amount of compound 2 is placed in a reaction vessel and heated to 60-80℃ until it is completely melted. KH560 is then added dropwise, and the temperature is raised to the set temperature to continue the reaction for a certain period of time. Specifically, the dropwise addition time of KH560 is 1-2 hours. The reaction temperature is 60-80℃, and the reaction time is 1-2 hours.

[0037] The molar ratio of compound 2 to KH560 is (1.02-1.20):1.

[0038] This application also provides a method for preparing polycarbonate materials, including the following steps: Under a nitrogen atmosphere and a pressure of 50–100 Pa, bisphenol A, compound 3, diester, and catalyst are mixed and stirred. The temperature is then raised to allow for transesterification at 120–150 °C for 1–2 hours. The temperature is then increased to 200–240 °C and the pressure to 150–250 Pa for polycondensation at 2–4 hours. After the reaction is complete, a novel polycarbonate is obtained.

[0039] The catalyst is one of sodium methoxide, sodium tert-butoxide, sodium tetraborate, lithium chloride, sodium sulfite, cesium carbonate, zinc acetate, lithium carbonate, tetrabutyl titanate, propyl titanate, isopropyl titanate, and propylene titanate; the carbonate diester is at least one of diphenyl carbonate, dimethyl carbonate, dimethyl dicarbonate, dimethyl terephthalate, diethyl carbonate, diphenyl phthalate, and dibutyl carbonate.

[0040] The molar ratio of bisphenol A, compound 4, and diester is (3-5):1:(4-6). The amount of catalyst used is 2%-15% of the molar sum of bisphenol A, compound 4, and diester. The resulting polycarbonate has a molecular weight of 20,000-100,000.

[0041] The following explanation uses specific preparation examples.

[0042] Preparation example of compound 1 The differences between Preparation Examples 1-3 of Compound 1 lie in the amounts of raw materials and process parameters, as detailed in Table 1. Specifically, the catalyst in Preparation Example 1 of Compound 1 was sodium methoxide, the catalyst in Preparation Example 2 of Compound 1 was sodium hydride, and the catalyst in Preparation Example 3 of Compound 1 was potassium hydroxide.

[0043] Table 1 Experimental parameters for the preparation of compound 1

[0044] Preparation example of compound 2 The differences between Preparation Examples 1-3 of Compound 2 lie in the amounts of raw materials and process parameters, as detailed in Table 2. Specifically, the phosphorylating agent in Preparation Example 1 of Compound 2 was phosphorus pentoxide, the phosphorylating agent in Preparation Example 2 of Compound 2 was polyphosphoric acid, and the phosphorylating agent in Preparation Example 3 of Compound 2 was 85% phosphoric acid.

[0045] Table 2 Experimental parameters for the preparation of compound 2

[0046] Preparation example of compound 3 The difference between Compound 3 in Examples 1-3 lies in the different amounts of raw materials and process parameters, as detailed in Table 3.

[0047] Table 3 Experimental parameters for the preparation of compound 3

[0048] Preparation examples of polycarbonate The differences between the preparation examples 1-9 of polycarbonate are the different amounts of raw materials and process parameters, as detailed in Tables 4 and 5.

[0049] Table 4 Experimental parameters for polycarbonate preparation 1

[0050] Table 5 Experimental parameters for polycarbonate preparation 2

[0051] Example This application provides a method for preparing low-temperature resistant cement aerogel, which mainly includes the following steps: Dissolve the adhesive in water, cool the solution to room temperature, then add the dispersant and cement in sequence and stir until homogeneous; then add the low-temperature resistant component, reinforcing fiber and foaming component in sequence and stir until homogeneous. The above solution was frozen using liquid nitrogen at a temperature of -100 to -200°C for 30 to 90 minutes, and then allowed to return to room temperature. It was then dried at a temperature of 40 to 90°C for 12 to 72 hours. After drying, cement aerogel material was obtained.

[0052] The adhesives include polyacrylic acid, polymethacrylic acid, polyacrylate, polymethacrylate, polyethylene glycol, polypropylene glycol, polyacrylamide, polymethacrylamide, polyurethane, polyvinyl alcohol, etc.; the dispersants are sulfonate water-reducing agents, naphthalene-based water-reducing agents, polycarboxylate water-reducing agents, phosphate-based water-reducing agents, etc.

[0053] The cement is sulfoaluminate cement or a mixture of sulfoaluminate cement and silicate cement, wherein when a mixture of sulfoaluminate cement and silicate cement is used, the mass ratio of sulfoaluminate cement to silicate cement is (60-100):(40-10).

[0054] The low-temperature resistant component is a polycarbonate powder processed into 10-300 μm, and the polycarbonate is a novel polycarbonate prepared in the preparation example. The reinforcing fiber is at least one of carbon fiber, glass fiber and polymer fiber, and the length of the reinforcing fiber is 1-10 mm and the diameter is 10-20 μm.

[0055] The foaming component is one of the following: sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, ammonium carbonate, ammonium nitrate, ammonium phosphate, monohydrogen phosphate, dihydrogen phosphate, ammonium nitrite, hydrogen peroxide, azobisisobutyronitrile, azobisisovalerate, azobisisoheptanenitrile, azoisobutyronitrile formamide, azobisisobutyramidine hydrochloride, and azobisisobutyronitrile acid.

[0056] The mass ratio of the dispersant to the cement is (0.001-0.05):1.

[0057] The mass ratio of reinforcing fiber to cement is (0.1-0.2):1.

[0058] The mass ratio of foaming component to cement is (0.25-0.5):1.

[0059] The mass ratio of the low-temperature resistant component to cement is (0.02-0.05):1.

[0060] The mass ratio of adhesive to cement is (0.002-0.005):1.

[0061] The mass ratio of water to cement is (0.2-0.5):1.

[0062] The following explanation is provided through specific examples.

[0063] Example 1 This embodiment provides a low-temperature resistant cement aerogel and its preparation method, as detailed below: (1) Dissolve 1g of adhesive polyacrylic acid (Mw=3000) in 20g of water; (2) Add 0.2g of Subote polycarboxylate superplasticizer PCA801 (50wt%) to the solution in (1), then add 100g of sulfoaluminate white cement Polar Bear 62.5 grade, stir for 30min, and stir at a speed of 500 r / min; (3) Add 2g of the low-temperature resistant component NPC-1 and stir until homogeneous; (4) Add 10g of carbon fiber and stir well; (5) Add 25g of the foaming component sodium bicarbonate and stir well; (6) Pour the solution from (5) into the mold and freeze it at -150°C for 45 minutes using liquid nitrogen; after freezing, thaw and return to room temperature. (7) After returning to room temperature, the mold is placed in an oven for drying. The oven temperature is set to 80°C. After drying, cement aerogel material sample S1 is obtained.

[0064] Example 2 This embodiment provides a low-temperature resistant cement aerogel and its preparation method, as detailed below: (1) Dissolve 1.5g of the adhesive polymethacrylic acid (Mw=4000) in 20g of water; (2) Add 0.2g of Subote polycarboxylate superplasticizer PCA902 (50wt%) to the solution in (1), then add 60g of sulfoaluminate white cement Polar Bear 62.5 grade and 40g of silicate cement Conch Cement 62.5 grade, stir for 30min, and stir at 500 r / min; (3) Add 2.5g of the low-temperature resistant component NPC-2 and stir well; (4) Add 12g of glass fiber and stir well; (5) Add 27g of the foaming component ammonium bicarbonate and stir well; (6) Pour the solution from (5) into the mold and freeze it at -150°C for 50 minutes using liquid nitrogen; after freezing, thaw and return to room temperature. (7) After returning to room temperature, put the mold into an oven for drying. The oven temperature is set to 80℃. After drying, cement aerogel material sample S2 is obtained.

[0065] Example 3 This embodiment provides a low-temperature resistant cement aerogel and its preparation method, as detailed below: (1) Dissolve 1.5g of the adhesive polyethylene glycol (Mw=5000) in 20g of water; (2) Add 0.2g of Subote polycarboxylate superplasticizer PCA801 (50wt%) to the solution in (1), then add 80g of sulfoaluminate white cement Polar Bear 62.5 grade and 20g of silicate cement Conch Cement 62.5 grade, stir for 30min, and stir at a speed of 500 r / min; (3) Add 2.8g of the low-temperature resistant component NPC-3 and stir until homogeneous; (4) Add 15g of glass fiber and stir well; (5) Add 27g of the foaming component hydrogen peroxide and stir well; (6) Pour the solution from (5) into the mold and freeze it at -150°C for 50 minutes using liquid nitrogen; after freezing, thaw and return to room temperature. (7) After returning to room temperature, the mold is placed in an oven for drying. The oven temperature is set to 40°C. After drying, cement aerogel material sample S3 is obtained.

[0066] Example 4 This embodiment provides a low-temperature resistant cement aerogel and its preparation method, as detailed below: (1) Dissolve 2.5g of the adhesive polypropylene glycol (Mw=4000) in 18g of water; (2) Add 0.2g of Subote polycarboxylate superplasticizer PCA801 (50wt%) to the solution in (1), then add 70g of sulfoaluminate white cement Polar Bear 62.5 grade and 30g of silicate cement Conch Cement 62.5 grade, stir for 30min, and stir at a speed of 500 r / min; (3) Add 3.5g of the low-temperature resistant component NPC-4 and stir until homogeneous; (4) Add 15g of carbon fiber and stir well; (5) Add 30g of the foaming component azobisisobutyronitrile and stir until homogeneous; (6) Pour the solution from (5) into the mold and freeze it at -150°C for 60 min using liquid nitrogen; after freezing, thaw and return to room temperature. (7) After returning to room temperature, the mold is placed in an oven for drying. The oven temperature is set to 80°C. After drying, cement aerogel material sample S4 is obtained.

[0067] Example 5 This embodiment provides a low-temperature resistant cement aerogel and its preparation method, as detailed below: (1) Dissolve 1.0 g of adhesive polyacrylamide (Mw=150000) in 20 g of water; (2) Add 0.2g of Subote polycarboxylate superplasticizer PCA902 (50wt%) to the solution in (1), then add 60g of sulfoaluminate white cement Polar Bear 62.5 grade and 40g of silicate cement Conch Cement 62.5 grade, stir for 30min, and stir at 500 r / min; (3) Add 4.5g of the low-temperature resistant component NPC-5 and stir well; (4) Add 13g of glass fiber and stir well; (5) Add 40g of foaming component ammonium dihydrogen phosphate and stir well; (6) Pour the solution from (5) into the mold and freeze it at -150°C for 50 minutes using liquid nitrogen; after freezing, thaw and return to room temperature. (7) After returning to room temperature, put the mold into an oven for drying. The oven temperature is set to 90℃. After drying, cement aerogel material sample S5 is obtained.

[0068] Example 6 This embodiment provides a low-temperature resistant cement aerogel and its preparation method, as detailed below: (1) Dissolve 2.5 g of the adhesive polymethacrylamide (Mw=250000) in 20 g of water; (2) Add 0.25g of Subote polycarboxylate superplasticizer PCA902 (50wt%) to the solution in (1), then add 100g of sulfoaluminate white cement Polar Bear 62.5 grade, stir for 30min, and stir at 500 r / min; (3) Add 4.8g of the low-temperature resistant component NPC-6 and stir until homogeneous; (4) Add 15g of carbon fiber and stir well; (5) Add 30g of the foaming component, ammonium monohydrogen phosphate, and stir until well mixed; (6) Pour the solution from (5) into the mold and freeze it at -150°C for 50 minutes using liquid nitrogen; after freezing, thaw and return to room temperature. (7) After returning to room temperature, put the mold into an oven for drying. The oven temperature is set to 90℃. After drying, cement aerogel material sample S6 is obtained.

[0069] Example 7 This embodiment provides a low-temperature resistant cement aerogel and its preparation method, as detailed below: (1) Dissolve 1.0g of the adhesive polyvinyl alcohol (Mw=200000) in 20g of water; (2) Add 0.2g of Subote polycarboxylate superplasticizer PCA801 (50wt%) to the solution in (1), then add 90g of sulfoaluminate white cement Polar Bear 62.5 grade and 10g of silicate cement Conch Cement 62.5 grade, stir for 30min, and stir at a speed of 500 r / min; (3) Add 2.5g of the low-temperature resistant component NPC-7 and stir well; (4) Add 16g of carbon fiber and stir well; (5) Add 32g of the foaming component ammonium carbonate and stir well; (6) Pour the solution from (5) into the mold and freeze it at -150°C for 60 min using liquid nitrogen; after freezing, thaw and return to room temperature. (7) After returning to room temperature, the mold is placed in an oven for drying. The oven temperature is set to 90°C. After drying, cement aerogel material sample S7 is obtained.

[0070] Example 8 This embodiment provides a low-temperature resistant cement aerogel and its preparation method, as detailed below: (1) Dissolve 0.75g of the adhesive polyurethane (Mw=100000) in 20g of water; (2) Add 0.2g of Subote polycarboxylate superplasticizer PCA902 (50wt%) to the solution in (1), then add 70g of sulfoaluminate white cement Polar Bear 62.5 grade and 30g of silicate cement Conch Cement 62.5 grade, stir for 30min, and stir at a speed of 500 r / min; (3) Add 3.5g of the low-temperature resistant component NPC-8 and stir well; (4) Add 18g of glass fiber and stir well; (5) Add 48g of foaming component azobisisobutyramidine hydrochloride and stir well; (6) Pour the solution from (5) into the mold and freeze it at -150°C for 60 min using liquid nitrogen; after freezing, thaw and return to room temperature. (7) After returning to room temperature, put the mold into an oven for drying. The oven temperature is set to 90℃. After drying, cement aerogel material sample S8 is obtained.

[0071] Example 9 This embodiment provides a low-temperature resistant cement aerogel and its preparation method, as detailed below: (1) Dissolve 1.2g of the adhesive polymethacrylic acid (Mw=80000) in 20g of water; (2) Add 0.2g of Subote polycarboxylate superplasticizer PCA902 (50wt%) to the solution in (1), then add 100g of sulfoaluminate white cement Polar Bear 62.5 grade, stir for 30min, and stir at a speed of 500 r / min; (3) Add 5g of the low-temperature resistant component NPC-9 and stir until homogeneous; (4) Add 20g of carbon fiber and stir well; (5) Add 50g of ammonium nitrate as the foaming component and stir well; (6) Pour the solution from (5) into the mold and freeze it at -150°C for 90 min using liquid nitrogen; after freezing, thaw and return to room temperature. (7) After returning to room temperature, the mold is placed in an oven for drying. The oven temperature is set to 90°C. After drying, cement aerogel material sample S9 is obtained.

[0072] Comparative Example The difference between Comparative Example 1 and Example 1 is that no adhesive is used.

[0073] The difference between Comparative Example 2 and Example 1 is that no water-reducing agent is used.

[0074] The difference between Comparative Example 3 and Example 1 is that no low-temperature resistant component is used.

[0075] The difference between Comparative Example 4 and Example 1 is that no reinforcing fibers are used.

[0076] The difference between Comparative Example 5 and Example 1 is that no foaming component is used.

[0077] The difference between Comparative Example 6 and Example 1 is that liquid nitrogen was used for cryogenic pore creation, the freezing temperature was -50°C and the freezing time was 30 minutes.

[0078] The difference between Comparative Example 7 and Example 1 is that the drying temperature is 35°C and the drying time is 12 hours.

[0079] Comparative Example 8 is the commercially available porous calcium silicate board HCS-20 from Hebei Huajun Insulation Materials Co., Ltd.

[0080] Performance testing Performance tests were conducted on the samples obtained in the examples and comparative examples, and the test results are shown in Table 1. The compressive strength test method was based on GB / T 34336-2017, and the thermal conductivity test method was based on GB / T 10295. The test results are shown in Table 6.

[0081] Table 6. Performance Test Results of Examples and Comparative Examples

[0082] Comparative analysis of the performance of Examples 1-9 and Comparative Examples 1-9 shows that the cement aerogel material provided by the present invention has good compressive strength at different temperatures of -60℃ and 30℃, and especially has excellent mechanical properties at a low temperature of -60℃. The sample material of the examples provided by the present invention has better thermal insulation performance, and the reduced density makes the sample a great advantage as a thermal insulation filling material for lightweight explosion-proof boxes.

[0083] Furthermore, in this invention, Comparative Example 1 lacks a binder, resulting in a decrease in the compressive strength of the sample. This indicates that the binder, in addition to binding the components, also enhances the strength of the aerogel material. Comparative Example 2 lacks a water-reducing agent, leading to a decrease in the compressive strength of the sample. This is because the water-reducing agent disperses the cement; when the cement is fully dispersed and mixed with the material, the material's strength is enhanced. Based on the performance of Comparative Example 3, it can be seen that the use of the low-temperature resistant component in this invention ensures compressive strength at lower temperatures. Furthermore, the thermal insulation performance and density are at a good level. Comparative Example 4 lacks reinforcing fibers, resulting in a decrease in density and thermal conductivity, along with a significant decrease in compressive strength. Comparative Example 5 lacks a foaming component, resulting in a comparative sample showing decreased thermal insulation performance and increased density. In Comparative Examples 6 and 7, if the temperature and time for freezing and creating pores using liquid nitrogen are reduced, or if the material drying temperature and time are not under the conditions of this invention, the performance of the prepared cement aerogel materials shows a significant decrease. Through the above comparative experiments, it can be seen that the experimental process conditions of each county in this invention are necessary. Only when the various parameters and processes are fully matched can the prepared cement aerogel material exhibit excellent mechanical properties, superior thermal insulation properties and low density at different temperatures.

[0084] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A low-temperature resistant polycarbonate, characterized in that, Its structure is shown in Equation 1: （1） In Equation 1, n is an integer, ranging from 20 to 100, and the weight-average molecular weight of polycarbonate ranges from 20,000 to 500,000; the structure of Q in the structural formula is shown in Equation 2: （2） In Equation 2, the structure of M is shown in Equation 3: （3） In Formula 3, X is methylene or ethoxy, where a, b, and c are independent of each other and are all integers; the value of a ranges from 2 to 6; the value of b ranges from 1 to 10; and the value of c ranges from 10 to 20.

2. A method for preparing a low-temperature resistant polycarbonate as described in claim 1, characterized in that, Includes the following steps: Preparation of compound 1: The diol initiator and the epoxide were subjected to an ethoxylation reaction to obtain compound 1; Preparation of compound 2: Compound 1 and a phosphorylating agent were subjected to a phosphorylation reaction to obtain compound 2; Preparation of compound 3: Compound 2 and silane coupling agent KH560 were reacted at 60-80℃ for 1-2 hours to obtain compound 3; Preparation of polycarbonate: Under a nitrogen atmosphere, bisphenol A, compound 3, diester and catalyst are subjected to transesterification reaction, followed by polycondensation reaction to obtain polycarbonate.

3. The method for preparing a low-temperature resistant polycarbonate according to claim 2, characterized in that, In the preparation steps of compound 1, the epoxide includes propylene oxide and ethylene oxide, and the molar ratio of the initiator, propylene oxide and ethylene oxide is 1:(1-10):(10-20).

4. The method for preparing a low-temperature resistant polycarbonate according to claim 2, characterized in that, In the preparation step of compound 2, the molar ratio of phosphorylating agent to compound is 1:(2-2.4), where the phosphorylating agent is converted to an equimolar amount of phosphoric acid.

5. The method for preparing a low-temperature resistant polycarbonate according to claim 2, characterized in that, In the preparation steps of compound 3, the molar ratio of compound 2 to silane coupling agent KH560 is (1.02-1.20):

1.

6. The method for preparing a low-temperature resistant polycarbonate according to claim 2, characterized in that, In the preparation step of the polycarbonate, the molar ratio of bisphenol A, compound 4 and diester is (3-5):1:(4-6).

7. The method for preparing a low-temperature resistant polycarbonate according to claim 6, characterized in that, In the preparation steps of the polycarbonate, an ester exchange reaction is first carried out at a temperature of 120-150℃ for 1-2 hours; then the temperature is further increased to 200-240℃ and the pressure is 150-250Pa to carry out a polycondensation reaction for 2-4 hours.

8. A low-temperature resistant cement aerogel material using a low-temperature resistant polycarbonate as described in claim 1, characterized in that, The raw materials include cement, water, binder, dispersant, low-temperature resistant component, reinforcing fiber and foaming component, the low-temperature resistant component being polycarbonate; the mass ratio of cement, dispersant, low-temperature resistant component, reinforcing fiber and foaming component, binder and water is 1: (0.001-0.05): (0.02-0.05): (0.1-0.2): (0.25-0.5): (0.002-0.005): (0.2-0.5).

9. A low-temperature resistant polycarbonate-based cement aerogel material according to claim 8, characterized in that, The low-temperature resistant component is polycarbonate powder with a particle size of 10-300 μm.

10. A method for preparing a low-temperature resistant cement aerogel material as described in any one of claims 8-9, characterized in that, Includes the following steps: Dissolve the adhesive in water, cool the solution to room temperature, then add the dispersant and cement in sequence and stir until homogeneous; then add the low-temperature resistant component, reinforcing fiber and foaming component in sequence and stir until homogeneous. The above solution was frozen using liquid nitrogen at a temperature of -100 to -200°C for 30 to 90 minutes, and then allowed to return to room temperature. It was then dried at a temperature of 40 to 90°C for 12 to 72 hours. After drying, cement aerogel material was obtained.

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