Vehicle-mounted high-temperature ceramic high-molecular polymer and preparation method thereof

Abstract

The invention relates to the technical field of high-molecular polymers, and particularly discloses a vehicle-mounted high-temperature ceramic high-molecular polymer and a preparation method thereof.According to the high-molecular polymer, a precursor capable of being ceramic is introduced to be mixed with a reaction monomer, deep fusion and function synergy of an organic phase and an inorganic phase on the molecular scale are achieved, and the high-temperature ceramic high-molecular polymer is obtained. And meanwhile, by controlling the thermal decomposition time of AZO, the AZO is matched with the fire development and the ceramization process, and a foamed ceramic composite protective layer can be formed at high temperature, so that more durable and more reliable thermal insulation protection is provided for the chip.

Description

Technical Field

[0001] This invention belongs to the field of polymers, specifically relating to vehicle-mounted high-temperature ceramicized polymers and their preparation methods. Background Technology

[0002] The "black box" (event recorder) of a high-speed train is responsible for recording massive amounts of data, including train operation status, key parameters, and driver control commands. It serves as crucial evidence for accident analysis, liability determination, and safety improvements. However, in a very small number of major accidents, especially those accompanied by fire, extreme temperatures exceeding 700°C can occur for extended periods, posing a devastating threat to the core data storage chip inside the black box. Traditional protective materials (such as epoxy resin and silicone) are prone to decomposition, carbonization, or melting under such harsh thermal conditions, losing their protective function and ultimately leading to chip damage and permanent data loss. This deprives accident investigations of their most important technical support.

[0003] Currently, while domestic and international standards for black boxes (such as fire protection standards) clearly stipulate short-term fire resistance performance, there is still room for improvement in the survivability of the internal chips when facing continuous and intense real-world fire scenarios. Although hydrogels can absorb a large amount of heat through the phase change (vaporization) of their water at high temperatures, forming a temporary and effective "thermal barrier" around the chip to slow heat transfer and buy valuable survival time for core data storage areas, when facing the thermal shock environment of a fire, hydrogels can only delay heat transfer and cannot provide durable protection for the chip.

[0004] Patent CN102408791A discloses a flame-retardant, smoke-suppressing, and moisture-regulating functional coating and its preparation method. It employs reverse-phase suspension polymerization to prepare "hydrotalcite / poly(sodium acrylate-acrylamide)" intercalated composite particles, which are then blended with a styrene-acrylic emulsion. This intercalated structure decomposes at 200-400℃, releasing CO2 / H2O, thus absorbing heat and diluting oxygen. However, the residue after hydrotalcite decomposition is a loose MgO-Al2O3 mixed oxide, without subsequent sintering for densification. As the temperature rises further, the residue collapses, reducing the protective effect. Therefore, this invention aims to provide a hydrogel material that can provide more durable and reliable thermal insulation protection for chips at extreme high temperatures, improving the data retention rate of black boxes in extreme accidents. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, this invention introduces a ceramizable precursor and reactant monomer mixture to achieve deep fusion and functional synergy of organic and inorganic phases at the molecular scale. At the same time, by controlling the timing of AZO thermal decomposition to match the fire development and ceramization process, an acrylic polymer that can form a foam ceramic composite protective layer when exposed to high temperatures is obtained, thus providing the chip with more durable and reliable thermal insulation protection.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention provides a vehicle-mounted high-temperature ceramicized polymer, comprising the following preparation steps: S1. Mix the initiator, reactant, and AZO@SiO2 evenly, add sodium hydroxide aqueous solution at 0-5℃, and stir for 20-30 min to obtain monomer aqueous solution; S2. Take out 30v%~50v% monomer aqueous solution, add precursor solution at room temperature, shear at 10000~15000rpm for 1~3min, then cool to 0~3℃ and let stand to mature to form prepolymer solution; S3. Under inert gas protection, add the internal crosslinking agent to the remaining monomer aqueous solution, dissolve it, and then add the prepolymer solution dropwise. The dropwise addition time is controlled at 30-40 min. After the dropwise addition is completed, continue stirring for 10-15 min. Then, perform gradient heat preservation, cutting, vacuum drying, and pulverization. Pass it through a 10-40 mesh sieve to obtain the vehicle-mounted high-temperature ceramicized polymer.

[0007] In some embodiments, in step S1, the AZO@SiO2 accounts for 5% to 10% of the total mass of the reactant monomers.

[0008] In some embodiments, in step S1, the initiator accounts for 0.02% to 0.07% of the total mass of the reactant monomers.

[0009] The organic network in the polymer provides room-temperature toughness, while the inorganic network provides a high-temperature framework. Pre-ceramization treatment with a precursor solution ensures a uniform distribution of the inorganic phase within the material, enabling it to rapidly and uniformly form a complete ceramic barrier under extreme thermal shock. Simultaneously, the AZO@SiO2 core-shell structure controls thermal decomposition behavior, matching the decomposition timing with fire development and the ceramization process. Ultimately, this results in a foam-ceramic composite protective layer with excellent thermal insulation, oxygen barrier properties, and mechanical strength.

[0010] In the preparation process, this invention prepolymerizes a precursor solution with a portion of the monomer aqueous solution. The active groups such as silanols and aluminum hydroxyl groups in the precursor can interact with the polymer chains through hydrogen bonds or possible covalent bonds, effectively anchoring and dispersing them within the growing polymer network, thus avoiding macroscopic phase separation between the inorganic and organic phases. Then, it cross-links and polymerizes with the main network, initially constructing a rudimentary structure within the material where the organic polymer network and the inorganic precursor network interpenetrate. This structure results in an extremely tight bond between the two, laying the foundation for subsequent synergistic reactions at high temperatures.

[0011] In some embodiments, the preparation steps of AZO@SiO2 in step S1 are as follows: Anhydrous ethanol, deionized water, and ammonia were used to prepare the reaction base solution. AZO was added and sonicated to form a suspension. Then TEOS was added dropwise, and stirring was continued for 1-3 hours after the addition was completed. The mixture was then allowed to cool naturally to room temperature and allowed to stand for 8-16 hours. MPS was then added and stirred at room temperature for 1-4 hours. After centrifugation, washing, vacuum drying, and sieving, AZO@SiO2 was obtained.

[0012] In some embodiments, the volume ratio of anhydrous ethanol, deionized water and ammonia in the reaction substrate is (80-84):(10-14):(3-7).

[0013] In some implementations, the MPS occupies 3% to 8% of the total volume of the TEOS.

[0014] This invention utilizes a sol-gel method to coat azodicarbonamide (AZO) particles with a layer of silica. AZO decomposes upon heating, generating a large amount of gas. The decomposition temperature of pure AZO is approximately 195-215°C. The silica shell, through its thermal barrier and physical constraint, delays the effective decomposition temperature of AZO to 350-400°C or even higher, allowing its decomposition timing to match the fire's progression and the material's own ceramization process. Simultaneously, the silica prevents premature decomposition of AZO under material polymerization, drying, and conventional storage conditions, ensuring the reliability and consistency of the final product's performance. Furthermore, the surface properties of the silica shell facilitate uniform dispersion in monomer aqueous solutions, preventing particle agglomeration and thus guaranteeing the uniformity of the final expansion.

[0015] In some embodiments, the preparation steps of the precursor solution in step S2 are as follows: glacial acetic acid and aluminum sol are added sequentially to deionized water, stirred at room temperature, then MTMS is added, and the temperature is raised to 30-40°C and stirred to obtain the precursor solution.

[0016] The silanol groups (Si-OH) generated from the hydrolysis of MTMS (methyltrimethoxysilane) in the precursor solution undergo condensation reactions during subsequent polymerization and high temperatures to form a three-dimensional Si-O-Si network, providing the skeletal framework for the ceramic layer. The Al-O / Al-OH units provided by the alumina sol are integrated into the silicon network, forming a more complex Si-O-Al composite inorganic network with higher thermal stability and mechanical strength. Compared to the sedimentation phenomenon that easily occurs in traditional physically mixed inorganic fillers, this composite inorganic network undergoes condensation sintering in the face of fire, generating an in-situ continuous ceramic phase mainly composed of silicon dioxide and aluminum oxide. This ceramic phase intertwines with the carbon formed by polymer pyrolysis to form a more reliable protective structure.

[0017] In some embodiments, the precursor solution also contains acetylacetone.

[0018] Acetylacetone can form a stable complex with aluminum ions in aluminum sol, which on the one hand inhibits premature gelation of aluminum sol under acidic conditions and improves the storage stability and operating window of the precursor solution; on the other hand, this complex can better interact with the subsequently added MTMS hydrolysis products (silanols), promote the pre-formation of Si-O-Al bonds in solution, and ensure that silicon and aluminum components begin to bind at the molecular scale.

[0019] In some embodiments, in step S3, the internal crosslinking agent accounts for 0.02% to 0.05% of the total mass of the reactant monomers.

[0020] In some embodiments, in step S3, the gradient heat preservation is sequentially performed as follows: heat preservation at 20-40℃ for 1-3 hours, heat preservation at 50-70℃ for 1-3 hours, and standing at 90-120℃ for 1-2 hours.

[0021] Compared with the prior art, the present invention has the following beneficial effects: This invention provides an acrylic polymer that can form a foam ceramic composite protective layer in the event of a fire. By prepolymerizing a precursor solution with a portion of the monomer aqueous solution, macroscopic phase separation between the inorganic and organic phases is avoided. Simultaneously, AZO@SiO2 works synergistically with the precursor solution. Supported by the ceramic framework formed by the precursor, the material can expand to form a thicker, stronger porous ceramic foam layer, greatly extending the heat transfer path and more effectively protecting the internal chip. Detailed Implementation

[0022] The present invention will be described below with reference to specific implementation schemes. It should be noted that the following embodiments are examples of the present invention and are used only to illustrate the invention, not to limit it. Other combinations and various modifications within the scope of the present invention can be made without departing from its spirit or scope. It is worth noting that, unless otherwise specified, the raw materials used in the following preparation examples and embodiments can be obtained from any commercially available manufacturer.

[0023] Preparation Example 1 The preparation steps of AZO@SiO2 are as follows: A reaction base solution was prepared using 400 mL of anhydrous ethanol, 60 mL of deionized water, and 25 mL of ammonia. 50 g of AZO was added, and the mixture was sonicated for 10 min (200 W, 20 kHz) to form a suspension. 45 mL of TEOS was added dropwise at 1.0 mL / min at 40 ℃ and 300 rpm. After the addition was complete, stirring was continued for 2 h. The mixture was then allowed to cool naturally to room temperature and aged for 12 h. Next, 3 mL of MPS was added, and the mixture was stirred at 300 rpm for 4 h at room temperature. The mixture was then centrifuged (4000 rpm, 5 min), washed three times with anhydrous ethanol, and vacuum dried at 80 ℃ for 12 h. The AZO@SiO2 was obtained by passing the solution through a 50-mesh sieve.

[0024] Preparation Example 2 The preparation steps of precursor solution-A are as follows: Add 10g of glacial acetic acid and 50g of aluminum sol (20wt% solid content) to 500g of deionized water, stir at room temperature for 30min, then add 2g of acetylacetone and 100g of MTMS, stir at 35°C for 40min to obtain precursor solution-A.

[0025] Preparation Example 3 The preparation steps of precursor solution-B are as follows: Add 10g of glacial acetic acid and 50g of aluminum sol (20wt% solid content) to 500g of deionized water, stir at room temperature for 30min, then add 100g of MTMS, stir at 35°C for 40min to obtain precursor solution-B.

[0026] Example 1 The preparation method of the vehicle-mounted high-temperature ceramicized polymer includes the following preparation steps: S1. Mix 0.04 g of potassium persulfate initiator with 78 g of acrylic acid and 6.5 g of AZO@SiO2 until homogeneous. Add 120 g of 25 wt% sodium hydroxide aqueous solution at 0 °C and stir for 25 min to obtain monomer aqueous solution. S2. Take out 40 v% monomer aqueous solution, add 15 g precursor solution-A at room temperature, shear at 12000 rpm for 2 min, then cool to 0℃ and let stand for 30 min to form prepolymer solution; S3. Under nitrogen protection, add 0.03g of N,N′-methylenebisacrylamide to the remaining monomer aqueous solution. After dissolving, add the prepolymer solution dropwise over a period of 40 minutes. After the addition is complete, continue stirring for 10 minutes. Then, maintain the temperature in a gradient manner: 30℃ for 2 hours, 60℃ for 2 hours, and 100℃ for 1.5 hours. Cut, vacuum dry at 30℃, pulverize, and pass through a 20-mesh sieve to obtain the vehicle-mounted high-temperature ceramicized polymer.

[0027] Example 2 The preparation method of the vehicle-mounted high-temperature ceramicized polymer includes the following preparation steps: S1. Mix 0.04 g of potassium persulfate initiator with 78 g of acrylic acid and 3.9 g of AZO@SiO2 until homogeneous. Add 120 g of 25 wt% sodium hydroxide aqueous solution at 5°C and stir for 20 min to obtain monomer aqueous solution. S2. Take out 30 v% monomer aqueous solution, add 15 g precursor solution-A at room temperature, shear at 10000 rpm for 3 min, then cool to 3℃ and let stand for 30 min to form prepolymer solution; S3. Under nitrogen protection, add 0.03g of N,N′-methylenebisacrylamide to the remaining monomer aqueous solution. After dissolving, add the prepolymer solution dropwise over a period of 30 minutes. After the addition is complete, continue stirring for 15 minutes. Then, maintain the temperature in a gradient manner: 20℃ for 3 hours, 50℃ for 3 hours, and 90℃ for 2 hours. Cut, vacuum dry at 30℃, pulverize, and pass through a 20-mesh sieve to obtain the vehicle-mounted high-temperature ceramicized polymer.

[0028] Example 3 The preparation method of the vehicle-mounted high-temperature ceramicized polymer includes the following preparation steps: S1. Mix 0.054 g of potassium persulfate initiator with 78 g of acrylic acid and 7.8 g of AZO@SiO2 until homogeneous. Add 120 g of 25 wt% sodium hydroxide aqueous solution at 0 °C and stir for 30 min to obtain monomer aqueous solution. S2. Take out 50 v% monomer aqueous solution, add 15 g precursor solution-A at room temperature, shear at 15000 rpm for 1 min, then cool to 0℃ and let stand for 30 min to form prepolymer solution; S3. Under nitrogen protection, add 0.038g of N,N′-methylenebisacrylamide to the remaining monomer aqueous solution. After dissolving, add the prepolymer solution dropwise over a period of 40 minutes. After the addition is complete, continue stirring for 15 minutes. Then, maintain the temperature in a gradient manner: 40℃ for 1 hour, 70℃ for 1 hour, and 120℃ for 1 hour. Cut, vacuum dry at 30℃, pulverize, and pass through a 20-mesh sieve to obtain the vehicle-mounted high-temperature ceramicized polymer.

[0029] Example 4 This embodiment provides a method for preparing a vehicle-mounted high-temperature ceramicized polymer. The specific implementation method is the same as in Embodiment 1, except that the precursor solution-A is replaced by an equal amount of precursor solution-B.

[0030] Comparative Example 1 This comparative example provides a method for preparing a vehicle-mounted high-temperature ceramicized polymer. The specific implementation method is the same as in Example 1, except that step S1 is adjusted as follows: S1. Add 0.04 g of potassium persulfate initiator and 78 g of acrylic acid to 120 g of 25 wt% sodium hydroxide aqueous solution at 0 °C, stir for 25 min to obtain monomer aqueous solution.

[0031] Comparative Example 2 This comparative example provides a method for preparing a vehicle-mounted high-temperature ceramicized polymer. The specific implementation method is the same as in Example 1, except that step S1 is adjusted as follows: S1. Mix 0.04 g of potassium persulfate initiator with 78 g of acrylic acid and 4.5 g of AZO until homogeneous. Add 120 g of 25 wt% sodium hydroxide aqueous solution at 0 °C and stir for 25 min to obtain monomer aqueous solution.

[0032] Comparative Example 3 This comparative example provides a method for preparing a vehicle-mounted high-temperature ceramicized polymer, comprising the following preparation steps: S1. Mix 0.04 g of potassium persulfate initiator with 78 g of acrylic acid and 6.5 g of AZO@SiO2 until homogeneous. Add 120 g of 25 wt% sodium hydroxide aqueous solution at 0 °C and stir for 25 min to obtain monomer aqueous solution. S2. Under nitrogen protection, add 0.03g of N,N′-methylenebisacrylamide to the monomer aqueous solution. After dissolving, add 15g of nano-sized aluminum oxide and continue stirring for 10 min. Then, maintain the temperature in a gradient manner: 30℃ for 2 h, 60℃ for 2 h, and 100℃ for 1.5 h. Cut, vacuum dry at 30℃, pulverize, and pass through a 20-mesh sieve to obtain the vehicle-mounted high-temperature ceramicized polymer.

[0033] Performance testing Chip protection tests were performed on the automotive high-temperature ceramicized polymers provided in Examples 1-4 and Comparative Examples 1-3. The results are shown in Table 1. 1) Test preparation: Assemble the sample, insert the USB cable, read the MD5 value, and save the screenshot; 2) Test conditions: The temperature was increased in five stages in sequence: 100℃ for 5 h, 300℃ for 60 min, 500℃ for 60 min, 650℃ for 30 min, and 750℃ for 5 min. Note that the temperature transition must be completed within 2 min. 3) Judgment criteria: After the test is completed, wait for the sample to cool down, disassemble the sample, take out the internal electronic disk, solder the USB cable, connect it to the computer to read the MD5 value. The data before and after the test must be consistent for the test to pass. If the test fails, remove the final stage of heating and repeat the four-stage heating (hold at 100℃ for 5 h, at 300℃ for 60 min, at 500℃ for 60 min, and at 650℃ for 30 min), and read the MD5 value. Repeat this operation until the test passes.

[0034] Table 1 Performance Test Results

[0035] As shown in Table 1, the polymers in Examples 1-3 can provide stable and long-lasting protection for the internal chip when exposed to extreme high temperatures. Compared to Example 1, the precursor solution used in Example 4 lacked acetylacetone, resulting in micro-gelation, which affected the uniform dispersion in the monomer solution and caused it to lose its protection for the chip when exposed to high temperatures of 750°C.

[0036] Compared to Example 1, Comparative Example 1 only has a precursor without AZO@SiO2, resulting in a dense but relatively thin ceramic layer with limited thermal insulation performance. Comparative Example 3 only has AZO@SiO2 without a precursor; although aluminum oxide was added for physical mixing, the material expands to form a low-strength, easily collapsing organic foam that rapidly ablates and fails at high temperatures. Combining Examples 1 and 2, it is clear that AZO without an outer protective layer begins to decompose between the first and second stages, failing to match the ceramization process in the third stage, thus negating the synergistic effect and impacting chip protection.

[0037] The embodiments and comparative examples described above do not limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing a vehicle-mounted high-temperature ceramicized polymer, characterized in that, The preparation process includes the following steps: S1. Mix the initiator, reactant, and AZO@SiO2 evenly, add sodium hydroxide aqueous solution at 0-5℃, and stir for 20-30 min to obtain monomer aqueous solution; S2. Take out 30v%~50v% monomer aqueous solution, add precursor solution at room temperature, shear at 10000~15000rpm for 1~3min, then cool to 0~3℃ and let stand to mature to form prepolymer solution; S3. Under inert gas protection, add the internal crosslinking agent to the remaining monomer aqueous solution, dissolve it, and then add the prepolymer solution dropwise. The dropwise addition time is controlled at 30-40 min. After the dropwise addition is completed, continue stirring for 10-15 min. Then, perform gradient heat preservation, cutting, vacuum drying, and pulverization. Pass it through a 10-40 mesh sieve to obtain the vehicle-mounted high-temperature ceramicized polymer.

2. The preparation method of the vehicle-mounted high-temperature ceramicized polymer according to claim 1, characterized in that, In step S1, the AZO@SiO2 accounts for 5% to 10% of the total mass of the reactant monomers.

3. The method for preparing the vehicle-mounted high-temperature ceramicized polymer according to claim 1, characterized in that, In step S1, the initiator accounts for 0.02% to 0.07% of the total mass of the reactant monomers.

4. The preparation method of the vehicle-mounted high-temperature ceramicized polymer according to claim 1, characterized in that, In step S1, the preparation steps of AZO@SiO2 are as follows: Anhydrous ethanol, deionized water, and ammonia were used to prepare the reaction base solution. AZO was added and sonicated to form a suspension. Then TEOS was added dropwise, and stirring was continued for 1-3 hours after the addition was completed. The mixture was then allowed to cool naturally to room temperature and allowed to stand for 8-16 hours. MPS was then added and stirred at room temperature for 1-4 hours. After centrifugation, washing, vacuum drying, and sieving, AZO@SiO2 was obtained.

5. The method for preparing the vehicle-mounted high-temperature ceramicized polymer according to claim 4, characterized in that, The volume ratio of anhydrous ethanol, deionized water and ammonia in the reaction substrate is (80-84):(10-14):(3-7).

6. The method for preparing the vehicle-mounted high-temperature ceramicized polymer according to claim 4, characterized in that, The MPS accounts for 3% to 8% of the total volume of TEOS.

7. The method for preparing the vehicle-mounted high-temperature ceramicized polymer according to claim 1, characterized in that, In step S2, the preparation steps of the precursor solution are as follows: glacial acetic acid and aluminum sol are added sequentially to deionized water, stirred at room temperature, then MTMS is added, and the temperature is raised to 30-40°C and stirred to obtain the precursor solution.

8. The method for preparing the vehicle-mounted high-temperature ceramicized polymer according to claim 7, characterized in that, The precursor solution also contains acetylacetone.

9. The method for preparing the vehicle-mounted high-temperature ceramicized polymer according to claim 1, characterized in that, In step S3, the internal crosslinking agent accounts for 0.02% to 0.05% of the total mass of the reactant monomers.

10. The method for preparing the vehicle-mounted high-temperature ceramicized polymer according to claim 1, characterized in that, In step S3, the gradient heat preservation is performed sequentially as follows: heat preservation at 20-40℃ for 1-3 hours, heat preservation at 50-70℃ for 1-3 hours, and standing at 90-120℃ for 1-2 hours.

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