PDMS-based fireproof composite material as well as preparation method and application thereof
By coating the surface of ammonium polyphosphate with organosilicon to form modified ammonium polyphosphate, the problems of platinum catalyst poisoning and compatibility were solved, and the PDMS-based composite material was successfully cured and its performance was improved, especially its fire resistance and mechanical stability.
Patent Information
- Application Number
- CN202511409883.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-29
- Publication Date
- 2025-12-16
AI Technical Summary
In the existing technology, platinum catalysts are easily poisoned by ammonium polyphosphate, which prevents PDMS-based composite materials from being successfully cured and molded. At the same time, the easy migration and poor compatibility of ammonium polyphosphate affect the flame retardancy and mechanical properties of the material.
Modified ammonium polyphosphate was used to form a compound by coating its surface with organosilicon and combining it with high-sodium glass powder to form a ceramic system, which avoids platinum catalyst poisoning and improves compatibility, thus preparing PDMS-based fire-retardant composite materials.
The successful curing and molding of PDMS-based composite materials has been achieved, which has improved the fire resistance, flame retardancy and mechanical stability of the materials, while simplifying the preparation process and reducing production costs.
Smart Images
Figure CN121136451A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of fire-retardant silicone rubber materials technology, specifically to a PDMS-based fire-retardant composite material, its preparation method, and its application. Background Technology
[0002] Organosilicon polymers, as unique high-molecular materials, have a molecular backbone composed of alternating silicon-oxygen bonds (Si-O-Si). This special structure endows them with many superior properties not found in traditional carbon-chain polymer materials, such as excellent high and low temperature resistance, maintaining stable performance over a very wide temperature range; excellent electrical insulation, effectively preventing current leakage and ensuring electrical safety; good chemical stability, withstanding a variety of chemical substances; and outstanding weather resistance, resisting the erosion of environmental factors such as ultraviolet radiation and ozone, and not easily aging with long-term use.
[0003] Compared to compounded silicone rubber composites, research on the preparation and performance of liquid silicone rubber composites in China started later, and related studies are relatively limited. However, with the rapid development of high-end manufacturing industries such as new energy vehicles, high-speed rail, and aerospace in my country, the demand for high-performance fire-resistant materials is becoming increasingly urgent. Liquid silicone rubber composites, with their unique advantages such as insulation, high and low temperature resistance, fluidity, room temperature curing capability, and ease of processing, have gradually become a hot topic in materials research. However, as a type of polymer material, liquid silicone rubber also suffers from poor fire resistance (flame retardancy, fire resistance, and thermal insulation), which greatly limits its widespread application in the aforementioned fields with extremely high fire resistance requirements.
[0004] To improve the fire resistance of organosilicon polymer composites, a ceramicization strategy emerged and was first applied to the compounding of silicone rubber composites. The core principle of this strategy is that, through ceramicization technology, the material, under high temperature or flame conditions, forms a continuous ceramic body with a certain strength through the ceramicization effect of the ceramic filler and the pyrolysis products of the polymer matrix. The formation of this ceramic body significantly improves the fire resistance of the material, effectively preventing flame spread and heat transfer, thus providing reliable fire protection.
[0005] In existing technologies, relevant research teams have successfully developed a "liquid-solid" vitrification system of ammonium polyphosphate / high-sodium glass powder, and have fully verified it in compounded silicone rubber and polyolefin systems. Experimental results show that the prepared vitrifiable silicone rubber / ammonium polyphosphate / high-sodium glass powder composite material and vitrifiable EVA / ammonium polyphosphate / high-sodium glass powder composite material both exhibit excellent fire resistance, which fully demonstrates the effectiveness of this vitrification system in improving the fire resistance of materials.
[0006] In order to develop a fast-drying insulating and fire-retardant potting compound that can be cured at room temperature, the research team of this invention attempted to apply the inventive concept of a "liquid-solid" ceramic system of ammonium polyphosphate / high-sodium glass powder to liquid silicone rubber composites. However, two key technical problems were encountered during the development process, which prevented the achievement of efficient fire resistance or even successful preparation of PDMS-based composites: Platinum catalyst poisoning problem: When the base formulation uses a platinum-catalyzed room temperature curable PDMS system, and the selected ceramic fireproof filler system is ammonium polyphosphate / high sodium glass powder, and the content of ammonium polyphosphate is high, the presence of phosphorus can easily lead to platinum catalyst poisoning, making it impossible for PDMS-based composite materials to be cured and formed smoothly, thus failing to form a material structure with the expected performance.
[0007] Flame retardancy and mechanical property stability issues: The ammonium polyphosphate content in the ammonium polyphosphate / high sodium glass powder ceramic system is relatively high. Ammonium polyphosphate has poor compatibility with the matrix and is also hygroscopic, which makes it easy for ammonium polyphosphate to migrate and precipitate from the matrix material, which has an adverse effect on the flame retardancy and mechanical properties of the material and cannot meet the strict requirements for material performance stability in practical applications. Summary of the Invention
[0008] Problems existing in the prior art: The high content of ammonium polyphosphate in the ammonium polyphosphate / high-sodium glass powder ceramic system easily poisons the platinum catalyst, preventing the successful curing of PDMS-based composite materials that rely on platinum-based catalysts for polymerization. To address these problems, this invention provides a PDMS-based fire-retardant composite material composed of components A and B in a weight ratio of 2:3 to 3:2. Component A, by weight, includes the following components: Vinyl-terminated silicone oil 50-60 parts, modified ammonium polyphosphate 2.5-7.5 parts, high-sodium glass powder 33.5-42.5 parts, inhibitor 0.4-0.6 parts, hydrogen-containing silicone oil 0.8-1.2 parts; Component B, by weight, comprises the following components: The composition includes 50-60 parts of vinyl-terminated silicone oil, 2.5-7.5 parts of modified ammonium polyphosphate, 33.5-42.5 parts of high-sodium glass powder, 0.2-0.3 parts of inhibitor, and 0.5-0.6 parts of catalyst; wherein the modified ammonium polyphosphate is a compound formed by coating the surface of ammonium polyphosphate with organosilicon.
[0009] Preferably, the vinyl-terminated silicone oil is a methyl-terminated vinyl silicone oil, and the dynamic viscosity of the methyl-terminated vinyl silicone oil at 25°C is 2300-2500 mPa·s.
[0010] Preferably, the preparation method of the modified ammonium polyphosphate includes the following steps: (1) Disperse 10g of ammonium polyphosphate evenly in 50mL of anhydrous ethanol to obtain an ammonium polyphosphate dispersion; (2) 1.56 g tetraethyl silicate and 0.84 g vinyltrimethoxysilane were uniformly dispersed in 20 mL of anhydrous ethanol to obtain an organosilicon modified solution; (3) Mix 1.5 mL of ammonia water, 1.5 mL of deionized water and 10 mL of anhydrous ethanol evenly to obtain an alkaline solution; (4) The organosilicon-modified solution and the alkaline solution are simultaneously added to the ammonium polyphosphate dispersion by stirring. After the addition is completed, the temperature of the reaction system is raised to 40-45°C and the reaction is stirred at a constant temperature for at least 4 hours. After the reaction is completed, the system is cooled to room temperature, and the solid product is collected by solid-liquid separation. The obtained solid product is washed with an amount of anhydrous ethanol and then dried under vacuum to obtain modified ammonium polyphosphate with organosilicon coating on the surface.
[0011] Preferably, the high-sodium glass powder is sodium glass powder with a Na2O content ≥15wt%, a SiO2 content ≥65wt%, and a softening point of 550±5℃.
[0012] Preferably, the inhibitor is ethynylcyclohexanol.
[0013] Preferably, the hydrogen-containing silicone oil is a side-containing hydrogen-containing silicone oil with a dynamic viscosity of 8–24 mPa·s at 25°C.
[0014] Preferably, the catalyst is a platinum-based catalyst.
[0015] A method for preparing a PDMS-based fire-retardant composite material involves rapidly mixing component A and component B at a temperature not exceeding 45°C according to the above-mentioned PDMS-based fire-retardant composite material formula, then pouring the mixture into a mold for curing and molding to obtain the PDMS-based fire-retardant composite material.
[0016] Preferably, the curing temperature is room temperature. More preferably, the curing temperature is 60-80°C.
[0017] The present invention has the following beneficial effects: (1) This invention uses a liquid-solid porcelainization system of ammonium polyphosphate / high sodium glass powder. Under high temperature or flame, the porcelainization effect of the porcelainization filler and the pyrolysis products of the polymer matrix form a continuous ceramic body with a certain strength, which effectively prevents the spread of flame and heat transfer, and significantly improves the fire resistance of the material, including flame retardancy, fire resistance and heat insulation. (2) This invention addresses the problem that in traditional platinum-catalyzed room-temperature curable PDMS systems, when using ammonium polyphosphate / high-sodium glass powder ceramic fireproof filler system, the platinum catalyst is poisoned by phosphorus, which prevents the material from being cured and formed smoothly. By coating ammonium polyphosphate with organosilicon and then adding it to the polymer matrix, the phenomenon of platinum catalyst poisoning is effectively avoided, ensuring that the PDMS-based composite material can be cured and formed smoothly. (3) The organosilicon layer of the modified ammonium polyphosphate obtained in this invention (which also contains polymerizable double bonds) can effectively improve the compatibility between ammonium polyphosphate and the polymer matrix, and can also solve the problem that ammonium polyphosphate is easy to absorb moisture and easily migrates and precipitates from the matrix material, thereby ensuring that the PDMS-based fireproof composite material obtained in this invention has good flame retardancy and mechanical property stability, and can meet the strict requirements for material performance stability in practical applications. (4) The PDMS-based fireproof composite material obtained by the present invention can be cured at room temperature. The preparation process is simple and quick, without the need for complex heating equipment and high energy consumption conditions, which reduces production costs and improves production efficiency. It is also beneficial to the on-site construction and application of the material. Attached Figure Description
[0018] Figure 1 SEM images of modified ammonium polyphosphate and the modified ammonium polyphosphate obtained in Example 1 of this invention (the right side is modified ammonium polyphosphate, and the left side is unmodified ammonium polyphosphate). Detailed Implementation
[0019] The present invention will be described in detail below with reference to embodiments. However, it should be understood that the following embodiments are merely illustrative examples of implementation of the present invention and are not intended to limit the scope of the present invention.
[0020] The high-sodium glass powder used in this invention was purchased from Foshan Nanhai Donggu New Material Co., Ltd., item number DZ1563, with parameters of Na2O content 19.76wt%, SiO2 content 66.32wt%, and softening point 550℃.
[0021] All catalysts used in this invention are platinum-based catalysts, purchased from Foshan Nanhai Donggu New Materials Co., Ltd., with a specification of 5000 ppm.
[0022] The hydrogen-containing silicone oil used in this invention was purchased from Shandong Dayi Chemical Co., Ltd., product number: DY-H202, with a dynamic viscosity of 22 mPa·s at 25℃.
[0023] The mass concentration of ammonia water used in this invention is 25%.
[0024] The inhibitor used in this invention is ethynylcyclohexanol.
[0025] The vinyl-terminated silicone oils used in this invention are all methyl-terminated vinyl-terminated silicone oils, purchased from Shandong Dayi Chemical Co., Ltd., product number V401.
[0026] Example 1
[0027] A PDMS-based fire-retardant composite material is composed of two components, A and B, in a weight ratio of 1:1. Component A, by weight, has the following composition: 50 parts vinyl-terminated silicone oil, 2.5 parts modified ammonium polyphosphate, 42.5 parts high-sodium glass powder, 0.4 parts inhibitor, and 0.8 parts hydrogen-containing silicone oil; Component B, by weight, has the following composition: 50 parts vinyl-terminated silicone oil, 2.5 parts modified ammonium polyphosphate, 42.5 parts high-sodium glass powder, 0.2 parts inhibitor, and 0.5 parts catalyst.
[0028] The modified ammonium polyphosphate is prepared as follows: (1) Disperse 10g of ammonium polyphosphate evenly in 50mL of anhydrous ethanol to obtain an ammonium polyphosphate dispersion; (2) 1.56 g tetraethyl silicate and 0.84 g vinyltrimethoxysilane were uniformly dispersed in 20 mL of anhydrous ethanol to obtain an organosilicon modified solution; (3) Mix 1.5 mL of ammonia water, 1.5 mL of deionized water and 10 mL of anhydrous ethanol evenly to obtain an alkaline solution; (4) The organosilicon-modified solution and the alkaline solution were simultaneously added dropwise to the ammonium polyphosphate dispersion while stirring. After the addition was complete, the temperature of the reaction system was raised to 45°C and the reaction was stirred at a constant temperature for 4 hours. After the reaction was completed, the mixture was naturally cooled to room temperature, and the solid product was collected by filtration. The obtained solid product was washed with an amount of anhydrous ethanol and then vacuum dried at 78°C for 12 hours to obtain modified ammonium polyphosphate with organosilicon coating on the surface (SEM image as shown in the attached instruction manual). Figure 1 (As shown).
[0029] The preparation method of the PDMS-based fire-retardant composite material is as follows: According to the formula, the raw materials of components A and B are stirred and mixed evenly. Then, components A and B are quickly mixed evenly at room temperature. After that, the mixture is poured into a mold and cured at room temperature for 24 hours to obtain PDMS-based fireproof composite material.
[0030] Example 2
[0031] A PDMS-based fire-retardant composite material is composed of two components, A and B, in a weight ratio of 1:1. Component A, by weight, has the following composition: 55 parts vinyl-terminated silicone oil, 5 parts modified ammonium polyphosphate, 38 parts high-sodium glass powder, 0.5 parts inhibitor, and 1 part hydrogen-containing silicone oil; Component B, by weight, has the following composition: 55 parts vinyl-terminated silicone oil, 5 parts modified ammonium polyphosphate, 38 parts high-sodium glass powder, 0.25 parts inhibitor, and 0.55 parts catalyst.
[0032] The modified ammonium polyphosphate is prepared as follows: (1) Disperse 10g of ammonium polyphosphate evenly in 50mL of anhydrous ethanol to obtain an ammonium polyphosphate dispersion; (2) 1.56 g tetraethyl silicate and 0.84 g vinyltrimethoxysilane were uniformly dispersed in 20 mL of anhydrous ethanol to obtain an organosilicon modified solution; (3) Mix 1.5 mL of ammonia water, 1.5 mL of deionized water and 10 mL of anhydrous ethanol evenly to obtain an alkaline solution; (4) The organosilicon-modified solution and the alkaline solution are simultaneously added dropwise to the ammonium polyphosphate dispersion while stirring. After the addition is complete, the temperature of the reaction system is raised to 45°C and the reaction is stirred at a constant temperature for 4 hours. After the reaction is completed, the mixture is naturally cooled to room temperature, and the solid product is collected by filtration. The obtained solid product is washed with an amount of anhydrous ethanol and then vacuum dried at 78°C for 12 hours to obtain modified ammonium polyphosphate with organosilicon coating on the surface.
[0033] The preparation method of the PDMS-based fire-retardant composite material is as follows: According to the formula, the raw materials of components A and B are stirred and mixed evenly. Then, components A and B are quickly mixed evenly at room temperature. After that, the mixture is poured into a mold and cured at room temperature for 36 hours to obtain PDMS-based fireproof composite material.
[0034] Example 3
[0035] A PDMS-based fire-retardant composite material is composed of two components, A and B, in a weight ratio of 1:1. Component A, by weight, has the following composition: 60 parts vinyl-terminated silicone oil, 7.5 parts modified ammonium polyphosphate, 33.5 parts high-sodium glass powder, 0.6 parts inhibitor, and 1.2 parts hydrogen-containing silicone oil; Component B, by weight, has the following composition: The mixture consists of 60 parts vinyl-terminated silicone oil, 7.5 parts modified ammonium polyphosphate, 33.5 parts high-sodium glass powder, 0.3 parts inhibitor, and 0.6 parts catalyst.
[0036] The modified ammonium polyphosphate is prepared as follows: (1) Disperse 10g of ammonium polyphosphate evenly in 50mL of anhydrous ethanol to obtain an ammonium polyphosphate dispersion; (2) 1.56 g tetraethyl silicate and 0.84 g vinyltrimethoxysilane were uniformly dispersed in 20 mL of anhydrous ethanol to obtain an organosilicon modified solution; (3) Mix 1.5 mL of ammonia water, 1.5 mL of deionized water and 10 mL of anhydrous ethanol evenly to obtain an alkaline solution; (4) The organosilicon-modified solution and the alkaline solution are simultaneously added dropwise to the ammonium polyphosphate dispersion while stirring. After the addition is complete, the temperature of the reaction system is raised to 45°C and the reaction is stirred at a constant temperature for 4 hours. After the reaction is completed, the mixture is naturally cooled to room temperature, and the solid product is collected by filtration. The obtained solid product is washed with anhydrous ethanol and then vacuum dried at 78°C for 12 hours to obtain modified ammonium polyphosphate with organosilicon coating on the surface.
[0037] The preparation method of the PDMS-based fire-retardant composite material is as follows: According to the formula, the raw materials of components A and B are stirred and mixed evenly. Then, components A and B are quickly mixed evenly at room temperature. After that, the mixture is poured into a mold and cured at room temperature for 48 hours to obtain PDMS-based fireproof composite material.
[0038] Example 4
[0039] A PDMS-based fire-retardant composite material is composed of two components, A and B, in a weight ratio of 1:1. Component A, by weight, has the following composition: 52 parts vinyl-terminated silicone oil, 4 parts modified ammonium polyphosphate, 40 parts high-sodium glass powder, 0.45 parts inhibitor, and 0.9 parts hydrogen-containing silicone oil; Component B, by weight, has the following composition: 52 parts vinyl-terminated silicone oil, 4 parts modified ammonium polyphosphate, 40 parts high-sodium glass powder, 0.22 parts inhibitor, and 0.52 parts catalyst.
[0040] The modified ammonium polyphosphate is prepared as follows: (1) Disperse 10g of ammonium polyphosphate evenly in 50mL of anhydrous ethanol to obtain an ammonium polyphosphate dispersion; (2) 1.56 g tetraethyl silicate and 0.84 g vinyltrimethoxysilane were uniformly dispersed in 20 mL of anhydrous ethanol to obtain an organosilicon modified solution; (3) Mix 1.5 mL of ammonia water, 1.5 mL of deionized water and 10 mL of anhydrous ethanol evenly to obtain an alkaline solution; (4) The organosilicon-modified solution and the alkaline solution are simultaneously added dropwise to the ammonium polyphosphate dispersion while stirring. After the addition is complete, the temperature of the reaction system is raised to 45°C and the reaction is stirred at a constant temperature for 4 hours. After the reaction is completed, the mixture is naturally cooled to room temperature, and the solid product is collected by filtration. The obtained solid product is washed with an amount of anhydrous ethanol and then vacuum dried at 78°C for 12 hours to obtain modified ammonium polyphosphate with organosilicon coating on the surface.
[0041] The preparation method of the PDMS-based fire-retardant composite material is as follows: According to the formula, the raw materials of components A and B are stirred and mixed evenly. Then, components A and B are quickly mixed evenly at room temperature. After that, the mixture is poured into a mold and cured at 60°C for 2 hours to obtain PDMS-based fireproof composite material.
[0042] Example 5
[0043] A PDMS-based fire-retardant composite material is composed of two components, A and B, in a weight ratio of 1:1. Component A, by weight, has the following composition: 58 parts vinyl-terminated silicone oil, 6 parts modified ammonium polyphosphate, 36 parts high-sodium glass powder, 0.55 parts inhibitor, and 1.1 parts hydrogen-containing silicone oil; Component B, by weight, has the following composition: 58 parts vinyl-terminated silicone oil, 6 parts modified ammonium polyphosphate, 36 parts high-sodium glass powder, 0.28 parts inhibitor, and 0.58 parts catalyst.
[0044] The modified ammonium polyphosphate is prepared as follows: (1) Disperse 10g of ammonium polyphosphate evenly in 50mL of anhydrous ethanol to obtain an ammonium polyphosphate dispersion; (2) 1.56 g tetraethyl silicate and 0.84 g vinyltrimethoxysilane were uniformly dispersed in 20 mL of anhydrous ethanol to obtain an organosilicon modified solution; (3) Mix 1.5 mL of ammonia water, 1.5 mL of deionized water and 10 mL of anhydrous ethanol evenly to obtain an alkaline solution; (4) The organosilicon-modified solution and the alkaline solution are simultaneously added dropwise to the ammonium polyphosphate dispersion while stirring. After the addition is complete, the temperature of the reaction system is raised to 45°C and the reaction is stirred at a constant temperature for 4 hours. After the reaction is completed, the mixture is naturally cooled to room temperature, and the solid product is collected by filtration. The obtained solid product is washed with an amount of anhydrous ethanol and then vacuum dried at 78°C for 12 hours to obtain modified ammonium polyphosphate with organosilicon coating on the surface.
[0045] The preparation method of the PDMS-based fire-retardant composite material is as follows: According to the formula, the raw materials of components A and B are stirred and mixed evenly. Then, components A and B are quickly mixed evenly at room temperature. After that, the mixture is poured into a mold and cured at 80°C for 1 hour to obtain PDMS-based fireproof composite material.
[0046] Comparative Example 1 is the same as Example 1, except that the same amount of ammonium polyphosphate is used in Comparative Example 1 to replace the modified ammonium polyphosphate in Example 1.
[0047] Comparative Example 2 is the same as Example 2, except that the modified ammonium polyphosphate was added in excess in Comparative Example 2, and the weight of modified ammonium polyphosphate added to components A and B was 10 parts each.
[0048] Comparative Example 3 is the same as Example 1, except that neither component A nor component B of Comparative Example 3 contains high-sodium glass powder. Component A, by weight, has the following composition: Vinyl-terminated silicone oil 89.6 parts, modified ammonium polyphosphate 4.5 parts, inhibitor 0.72 parts, hydrogen-containing silicone oil 1.44 parts; Component B, by weight, has the following composition: The composition consists of 89.9 parts vinyl-terminated silicone oil, 4.5 parts modified ammonium polyphosphate, 0.4 parts inhibitor, and 0.9 parts catalyst.
[0049] Comparative Example 4 is the same as Example 1, except that in the preparation of modified ammonium polyphosphate in Comparative Example 4, tetraethyl silicate was replaced with an equal amount of vinyltrimethoxysilane.
[0050] Comparative Example 5 is the same as Example 1, except that the amount of tetraethyl silicate and vinyltrimethoxysilane added in the preparation of modified ammonium polyphosphate in Comparative Example 4 is 1.2g.
[0051] Performance testing
[0052] The relevant performance tests were conducted on the embodiments and comparative examples of the present invention, and the test results are shown in Table 1 and Table 1 (continued).
[0053] Flame retardancy: evaluated by limiting oxygen index, the test standard is GB / T 2406.2-2022.
[0054] Hydrophobicity: The same volume of the composite materials obtained in the embodiments and comparative examples of the present invention were added into the mold and cured at room temperature. The mold was tilted so that the surface of the material was at a 45-degree angle to the horizontal plane. Then, 10 mL of deionized water was poured from the top and the surface of the material was observed to see if there were obvious water stains.
[0055] Fire resistance and thermal insulation: These are evaluated and predicted by observing the size and morphology of the samples after pyrolysis at 800℃. If the pyrolysis products maintain the same size as the initial sample or show no significant shrinkage, the fire resistance is considered excellent. If the morphology of the pyrolysis products changes significantly, such as with cracks or holes, the thermal insulation performance is considered poor. Similarly, the denser and more intact the pyrolysis products, the better the thermal insulation performance.
[0056] Stability: The flame retardant properties of the material were evaluated by the decay of flame retardant properties over aging time. The material was placed under aging conditions of 85℃ / 85% humidity for 7 days. After aging, the limiting oxygen index of the material was tested according to GB / T 2406.2-2022 standard.
[0057] Curing performance (deformation resistance): Wearing nitrile rubber gloves, press the material surface with your fingers and observe whether the sample sticks to the gloves, whether the sample at the pressed area has obvious deformation, and whether it can recover quickly.
[0058] Table 1 ,
[0059] Continued from Table 1 ,
[0060] In Table 1, the " / " sign indicates that the sample could not be cured and its properties could not be tested. The reason for the inability to cure is that since ammonium polyphosphate is not coated with organosilicon, phosphorus can easily come into contact with the catalyst, causing catalyst poisoning and preventing the sample from curing completely, thus failing to obtain a good product.
[0061] Thermal insulation rating and hardness rating express, The larger the quantity, the higher the grade and the better the performance. The hardness grade is tested using a similar test method as per the group standard for similar ceramic refractory silicone materials. This involves gently pressing the ablated material with a finger to assess its hardness. However, because the ablated sample is too thin or deformed, it is impossible to quantitatively test its hardness. The heat insulation grade is estimated by whether the sample surface is dense and whether there are cracks after ablation. A dense sample surface means that flames and heat cannot pass through, indicating excellent heat insulation performance. Conversely, if the sample surface has cracks or even obvious holes, flames and heat can pass through the sample during ablation, allowing heat to spread and transfer.
[0062] The test results above show that the PDMS-based fire-retardant composite material obtained in this invention exhibits excellent overall performance. Compared with the PDMS-based fire-retardant composite material obtained in the comparative example, it has superior flame retardant properties, fire resistance, and heat insulation. Furthermore, the PDMS-based fire-retardant composite material obtained in this invention demonstrates superior hydrophobicity and stability. In addition, the preparation method of this invention is simple to operate, easy to implement, and can meet the room temperature curing requirements of the basic formulation materials for cooperating enterprises, thus showing good application prospects.
[0063] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.
Claims
1. A PDMS-based fire-retardant composite material, characterized in that, It is composed of two components, A and B, in a weight ratio of 2:3 to 3:
2. Component A, by weight, includes the following ingredients: Vinyl-terminated silicone oil 50-60 parts, modified ammonium polyphosphate 2.5-7.5 parts, high-sodium glass powder 33.5-42.5 parts, inhibitor 0.4-0.6 parts, hydrogen-containing silicone oil 0.8-1.2 parts; Component B, by weight, comprises the following components: The composition includes 50-60 parts of vinyl-terminated silicone oil, 2.5-7.5 parts of modified ammonium polyphosphate, 33.5-42.5 parts of high-sodium glass powder, 0.2-0.3 parts of inhibitor, and 0.5-0.6 parts of catalyst; wherein the modified ammonium polyphosphate is a compound formed by coating the surface of ammonium polyphosphate with organosilicon.
2. The PDMS-based fire-retardant composite material according to claim 1, characterized in that, The vinyl-terminated silicone oil is a methyl-terminated vinyl silicone oil, and the dynamic viscosity of the methyl-terminated vinyl silicone oil at 25°C is 2300–2500 mPa·s.
3. The PDMS-based fire-retardant composite material according to claim 1, characterized in that, The preparation method of the modified ammonium polyphosphate includes the following steps: (1) Disperse 10g of ammonium polyphosphate evenly in 50mL of anhydrous ethanol to obtain an ammonium polyphosphate dispersion; (2) 1.56 g tetraethyl silicate and 0.84 g vinyltrimethoxysilane were uniformly dispersed in 20 mL anhydrous ethanol to obtain an organosilicon modified solution; (3) Mix 1.5 mL of ammonia water, 1.5 mL of deionized water and 10 mL of anhydrous ethanol evenly to obtain an alkaline solution; (4) The organosilicon-modified solution and the alkaline solution are simultaneously added to the ammonium polyphosphate dispersion by stirring. After the addition is completed, the temperature of the reaction system is raised to 40-45°C and the reaction is stirred at a constant temperature for at least 4 hours. After the reaction is completed, the system is cooled to room temperature, and the solid product is collected by solid-liquid separation. The obtained solid product is washed with an amount of anhydrous ethanol and then dried under vacuum to obtain modified ammonium polyphosphate with organosilicon coating on the surface.
4. The PDMS-based fire-retardant composite material according to claim 1, characterized in that, The high-sodium glass powder is sodium glass powder with a Na2O content ≥15wt%, a SiO2 content ≥65wt%, and a softening point of 550±5℃.
5. The PDMS-based fire-retardant composite material according to claim 1, characterized in that, The inhibitor is ethynylcyclohexanol.
6. The PDMS-based fire-retardant composite material according to claim 1, characterized in that, The hydrogen-containing silicone oil is a side-containing hydrogen-containing silicone oil with a dynamic viscosity of 8–24 mPa·s at 25°C.
7. The PDMS-based fire-retardant composite material according to claim 1, characterized in that, The catalyst is a platinum-based catalyst.
8. A method for preparing a PDMS-based fire-retardant composite material, characterized in that, According to the formulation of the PDMS-based fire-retardant composite material according to any one of claims 1-7, component A and component B are rapidly mixed evenly at a temperature not exceeding 45°C, and then poured into a mold for curing to obtain the PDMS-based fire-retardant composite material.
9. The method for preparing a PDMS-based fire-retardant composite material according to claim 8, characterized in that, The curing temperature is room temperature.
10. The method for preparing a PDMS-based fire-retardant composite material according to claim 8, characterized in that, The curing temperature is 60-80℃.