Vinyl hyperbranched organosilicon reinforced temperature-resistant and ablation-resistant addition type silicone rubber composite material and preparation method thereof

Abstract

This invention discloses a high-temperature resistant and ablation-resistant addition-type silicone rubber composite material reinforced with vinyl hyperbranched silicone and its preparation method, belonging to the technical field of high-temperature resistant polymer protective materials. This invention uses polyvinyl hyperbranched silicone resin as the resin system, vinyl silicone rubber as the matrix, hydrogen-containing silicone oil as the crosslinking agent, and boron nitride, alumina, zirconium oxide, silicon carbide, fumed silica, and hollow glass microspheres as fillers. A platinum-based catalyst is used to form a synergistic crosslinking composite system of ablation resistance and thermal insulation. This invention significantly improves the mechanical strength and high-temperature stability of the material through the crosslinking reinforcement effect of vinyl hyperbranched silicone resin, while reducing the thermal conductivity. The prepared material exhibits excellent high-temperature ablation resistance, mechanical strength, and thermal insulation properties, and can be applied in engine thermal insulation layers, ablation-resistant protective structures, and aerospace thermal protection materials.

Description

Technical Field

[0001] This invention belongs to the technical field of high-temperature resistant polymer protective materials, specifically relating to a high-temperature resistant and ablation-resistant addition-type silicone rubber composite material based on vinyl hyperbranched organosilicon and its preparation method. Background Technology

[0002] Engine thermal protection materials typically need to withstand extreme environments during service, such as high-temperature combustion gas erosion, severe thermal shock, and high-speed airflow shearing. This places extremely high demands on the materials' ablation resistance, mechanical strength, and thermal insulation performance. Especially in areas such as the engine combustion chamber, nozzle outer wall, and thermal insulation layer, the materials not only need to possess excellent ablation resistance but also maintain a certain degree of flexibility and structural integrity.

[0003] Currently, most ablation-resistant silicone rubber materials are modified with linear silicone resin or reinforced with a single inorganic filler. While these methods can improve the heat resistance of the material to some extent, they still have significant shortcomings. For example, linear organosilicon modifiers have low functionality, making it difficult to significantly increase the crosslinking density, resulting in limited improvement in material strength. Traditional fillers mostly rely on physical filling, resulting in weak interfacial bonding with the matrix. At high temperatures, they easily form a loose carbon layer, thereby reducing ablation resistance.

[0004] In addition, existing technologies often focus on flame retardancy or enhancing a single function in filler design, lacking a coordinated design for ablation resistance, structural strength and thermal insulation performance. This makes it easy for the material to collapse during high-temperature ablation, making it difficult to meet the application requirements of high strength and low ablation rate at the same time.

[0005] In particular, there are currently few technologies that utilize hyperbranched organosilicon with multifunctional structures as a reactive reinforcing phase to improve the density of the addition-type silicone rubber network structure through chemical crosslinking, thereby achieving simultaneous improvement in mechanical properties and ablation resistance.

[0006] Therefore, it is necessary to develop a high-performance ablation-resistant silicone rubber composite material that can improve the crosslinking density of addition-cured silicone rubber, enhance high-temperature ablation stability, and also take into account thermal insulation performance.

[0007] In the existing technology, research on high-temperature resistant silicone rubber materials has a certain foundation. For example, patent CN110903656A discloses a low-volatility, high-temperature resistant, and thermally conductive silicone putty material and its preparation method. This technology improves the heat resistance and thermal conductivity of silicone materials by adding thermally conductive fillers and high-temperature resistant additives. However, this type of material is mainly designed for thermal conductivity and low volatility, and its ablation resistance is insufficient. It does not construct an effective ablation-resistant structural system for extreme high-temperature ablation environments. At the same time, its filler system mainly focuses on improving thermal conductivity, making it difficult to form a continuous and dense ceramic protective layer at high temperatures. Under continuous high-temperature flame erosion conditions, the material's structural stability remains limited, making it difficult to meet the requirements of ablation-resistant protection applications.

[0008] Patent CN114958001A discloses a high-strength ablation-resistant silicone rubber and its preparation method. This technology improves the mechanical properties and ablation resistance of silicone rubber by introducing reinforcing fillers and high-temperature resistant components. Although this method can improve the material strength to a certain extent, its modification mainly relies on inorganic filler reinforcement, which is insufficient for controlling the cross-linked network structure of the silicone rubber matrix. Therefore, the material may still experience strength decay and structural integrity reduction at high temperatures. Furthermore, the ablation resistance of this type of material mainly relies on the passive protective effect of the fillers. The synergistic ceramic design among various high-temperature resistant fillers is insufficient, making it difficult to form a stable and dense protective layer during ablation. Therefore, there is still room for improvement in its resistance to continuous ablation.

[0009] In addition, patent CN118184952A discloses a vinyl hyperbranched organosilicon modified silicone rubber release film material. By introducing hyperbranched organosilicon with multiple vinyl functions, it improves the crosslinking uniformity and surface properties of silicone rubber, thereby enhancing the release performance and coating stability of the material. It is mainly used in the fields of release film and electronic packaging materials. However, this technology mainly focuses on the surface performance control of silicone rubber and does not involve the improvement of material structural stability and ablation resistance under high temperature ablation environment. It is significantly different from the present invention in terms of technical objectives and application fields, which are aimed at high temperature structural reinforcement and ceramic protection design of ablation-resistant protective materials.

[0010] Based on existing technologies, ablation-resistant silicone rubber materials generally suffer from the following shortcomings: First, matrix modification is mostly concentrated on filler reinforcement or ordinary silicone resin modification, which is insufficient for strengthening the three-dimensional cross-linked network of silicone rubber, making it difficult to simultaneously improve the material's mechanical strength and ablation resistance; second, ablation-resistant designs mostly rely on single-function fillers and lack the synergistic mechanism of multi-component high-temperature resistant fillers, resulting in insufficient structural stability of the protective layer at high temperatures; third, the material is prone to structural softening or local collapse during high-temperature ablation, affecting long-term service reliability. Summary of the Invention

[0011] One technical problem solved by this invention is to provide a high-temperature resistant and ablation-resistant addition-type silicone rubber composite material based on vinyl hyperbranched organosilicon, which achieves a synergistic improvement in material strength, ablation resistance, and thermal insulation performance. Another technical problem to be solved by this invention is to provide a method for preparing a high-temperature resistant and ablation-resistant addition-type silicone rubber composite material based on vinyl hyperbranched organosilicon. This method uses vinyl hyperbranched organosilicon as a reactive reinforcing component, which can participate in the silicone rubber addition crosslinking reaction to form a high crosslinking density three-dimensional network structure inside the material, thereby improving the material's mechanical properties.

[0012] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0013] A high-temperature resistant and ablation-resistant addition-type silicone rubber composite material based on vinyl hyperbranched organosilicon reinforced with vinyl hyperbranched organosilicon is composed of the following components in parts by weight: 100 parts vinyl silicone rubber, 5-40 parts vinyl hyperbranched organosilicon, 5-20 parts fumed silica, 5-20 parts hexagonal boron nitride, 5-30 parts hollow glass microspheres, 5-40 parts alumina, 5-40 parts zirconium oxide, 5-20 parts silicon carbide, 2-30 parts hydrogen-containing silicone oil, 0.1-2 parts platinum catalyst, and 0.1-1 parts alkynol inhibitor.

[0014] Further, it is composed of the following components in parts by weight: 100 parts vinyl silicone rubber, 30 parts vinyl hyperbranched organosilicon, 15 parts fumed silica, 15 parts hexagonal boron nitride, 20 parts hollow glass microspheres, 30 parts alumina, 25 parts zirconium oxide, 15 parts silicon carbide, 15 parts hydrogen-containing silicone oil, 1 part platinum catalyst, and 0.5 parts alkynol inhibitor.

[0015] Furthermore, the vinyl silicone rubber has a viscosity of 5000-20000 mPa·s and a vinyl mass fraction of 0.1%-3%; the vinyl hyperbranched silicone resin has a viscosity of 300-1000 mPa·s and a vinyl content of 5-10%.

[0016] Furthermore, the average particle size of the fumed silica is 10-50 nm, the average particle size of the hexagonal boron nitride is 1-10 μm, the average particle size of the alumina is 1-5 μm, the average particle size of the zirconium oxide is 1-5 μm, the average particle size of the silicon carbide is 1-10 μm, and the average particle size of the hollow glass microspheres is 20-100 μm.

[0017] Furthermore, the platinum catalyst is selected from one or more of the following: Karstedt catalyst, chloroplatinic acid, and chloroplatinum-divinyltetramethyldisiloxane complex.

[0018] Furthermore, the alkynol inhibitor is selected from one or more of 2-methyl-3-butyn-2-ol, 1-ethynylcyclohexanol, 3-methyl-1-butyn-3-ol, and 3,5-dimethyl-1-hexyn-3-ol.

[0019] Furthermore, the viscosity of the hydrogen-containing silicone oil is 100-1000 mPa·s, and the Si-H content is 0.5-1.6 wt%.

[0020] Furthermore, the preparation method of the vinyl hyperbranched organosilicon-reinforced temperature-resistant and ablation-resistant addition-type silicone rubber composite material includes the following steps:

[0021] 1) Add the vinyl hyperbranched silicone to the vinyl silicone rubber and mix thoroughly;

[0022] 2) Add fumed silica, boron nitride, alumina, zirconium oxide, silicon carbide and hollow glass microspheres, and add alkynyl alcohol inhibitors and mix evenly.

[0023] 3) After the system has cooled, add hydrogen-containing silicone oil and platinum catalyst and mix.

[0024] 4) Apply the adhesive to the surface of the substrate or mold and cure it to obtain an ablation-resistant silicone rubber composite material.

[0025] Furthermore, in step 4), the curing temperature is 100-130℃ and the curing time is 4-8h.

[0026] Furthermore, the application of the vinyl hyperbranched organosilicon-reinforced addition-type silicone rubber composite material in ablation-resistant protective materials includes engine thermal insulation layers, aerospace thermal protection structures, ablation-resistant sealing materials, and high-temperature thermal insulation coatings.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] (1) The present invention uses vinyl hyperbranched organosilicon as a reactive reinforcing component, which can participate in the addition crosslinking reaction of silicone rubber to form a three-dimensional network structure with high crosslinking density inside the material, thereby improving the mechanical properties of the material; at the same time, the multi-scale high-temperature resistant filler forms a stable inorganic skeleton at high temperature, thereby improving the ablation resistance of the material; the hollow glass microspheres reduce the thermal conductivity of the material and improve the thermal insulation performance; the material can be cured under normal pressure, the preparation process is simple, and it has good engineering application value.

[0029] (2) The vinyl hyperbranched silicone resin used in this invention is a type of vinyl hyperbranched silicone resin with a unique highly branched three-dimensional structure and low viscosity. The silicone rubber modified with it can increase the processability. At the same time, because it contains a high content of vinyl functional groups, it can undergo hydrosilylation reaction with hydrogen-containing silicone oil and form a double crosslinked network after curing with vinyl silicone rubber. Compared with linear or slightly branched silicone resins, it has higher mechanical strength, thermal stability and chemical stability.

[0030] (3) By constructing a hyperbranched organosilicon network structure that can participate in cross-linking and combining it with the synergistic ceramic design of multi-component high-temperature resistant fillers, this invention improves the ablation resistance and high-temperature structural stability of the material while ensuring the material's flexibility, thereby achieving a synergistic improvement in the material's mechanical properties and ablation resistance. Attached Figure Description

[0031] Figure 1 Synthetic route diagram for preparing vinyl hyperbranched organosilicon-reinforced ablation-resistant addition-type silicone rubber composite material for this application;

[0032] Figure 2 The figures show the tensile test results of the samples prepared in Examples 1-2 and the comparative examples of this application;

[0033] Figure 3 Thermogravimetric curves of the samples prepared in Examples 1-2 and the comparative examples of this application at 30-1000℃ under a nitrogen atmosphere;

[0034] Figure 4 These are before-and-after comparison images of the samples prepared in Examples 1-2 and the comparative examples of this application. Detailed Implementation

[0035] The present invention will be further illustrated below with reference to specific embodiments. These embodiments are implemented based on the technical solutions of the present invention, and it should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0036] The vinyl 107 silicone rubber used in the following examples was purchased from Hubei Longsheng Sihai New Materials, the fumed silica was purchased from Cabot Corporation of the United States, the hexagonal boron nitride was purchased from China Metallurgical New Materials, the alumina, zirconium oxide, and silicon carbide were purchased from China Metallurgical New Materials, the hollow glass microspheres were purchased from Yituo Technology, the hydrogen-containing silicone oil was purchased from Hubei Longsheng Sihai New Materials, and the 2-methyl-3-butyn-2-ol, Karstedt catalyst, 1-ethynylcyclohexanol, and chloroplatinic acid complexing catalyst were purchased from Tianjin Xiens.

[0037] The method for preparing vinyl hyperbranched organosilicon used in the following examples adopts Example 1 of Chinese Invention Patent Publication No. CN118185016A: A method for preparing low-viscosity hyperbranched organosilicon resin with high vinyl content.

[0038] Example 1

[0039] Depend on Figure 1As shown, this invention provides a method for preparing a high-temperature resistant and ablation-resistant addition-type silicone rubber composite material reinforced with vinyl hyperbranched organosilicon. The formula is as follows by mass: 100 parts of vinyl 107 silicone rubber (viscosity 12000 mPa·s, vinyl content 1.0%), 20 parts of vinyl hyperbranched organosilicon (viscosity 100-1000 mPa·s), 10 parts of fumed silica (average particle size 20 nm), 10 parts of hexagonal boron nitride (average particle size 5 μm), 20 parts of alumina (average particle size 2 μm), 15 parts of zirconium oxide (average particle size 2 μm), 10 parts of silicon carbide (average particle size 5 μm), 15 parts of hollow glass microspheres (average particle size 50 μm), 10 parts of hydrogen-containing silicone oil (viscosity 200 mPa·s, Si-H content 1.1 wt%), 0.3 parts of 2-methyl-3-butyn-2-ol, and 0.5 parts of Karstedt catalyst.

[0040] Includes the following steps:

[0041] Vinyl hyperbranched organosilicon was added to vinyl 107 silicone rubber and premixed at room temperature until homogeneous. Then, fumed silica, hexagonal boron nitride, alumina, zirconium oxide, silicon carbide and hollow glass microspheres were added, along with a 2-methyl-3-butyn-2-ol inhibitor, and mixed evenly. Hydrogen-containing silicone oil and Karstedt catalyst were then added and mixed evenly. The mixture was then evenly coated into a mold and cured at 120°C under normal pressure for 6 hours to obtain a vinyl hyperbranched organosilicon-reinforced ablation-resistant addition-curing silicone rubber composite material.

[0042] Example 2

[0043] A method for preparing a temperature-resistant and ablation-resistant addition-type silicone rubber composite material based on vinyl hyperbranched organosilicon, wherein the formula is as follows by mass parts: 100 parts of vinyl 107 silicone rubber (viscosity 8000 mPa·s, vinyl content 0.8%), 30 parts of vinyl hyperbranched organosilicon (viscosity 100-1000 mPa·s), 15 parts of fumed silica (particle size 30 nm), 15 parts of hexagonal boron nitride (particle size 3 μm), 30 parts of alumina (particle size 1 μm), 25 parts of zirconium oxide (particle size 1 μm), 15 parts of silicon carbide (particle size 3 μm), 20 parts of hollow glass microspheres (particle size 40 μm), 15 parts of hydrogen-containing silicone oil (viscosity 400 mPa·s, Si-H content 0.8 wt%), 0.5 parts of 1-acetylenecyclohexanol, and 1 part of chloroplatinic acid complexing catalyst.

[0044] Includes the following steps:

[0045] Vinyl hyperbranched organosilicon was added to vinyl 107 silicone rubber and premixed at room temperature until homogeneous. Then, fumed silica, hexagonal boron nitride, alumina, zirconium oxide, silicon carbide and hollow glass microspheres were added, along with a 1-acetylenecyclohexanol inhibitor, and mixed evenly. Then, hydrogen-containing silicone oil and chloroplatinic acid complexing catalyst were added and mixed evenly. The rubber compound was then evenly coated into a mold and cured at 150°C under normal pressure for 4 hours to obtain a vinyl hyperbranched organosilicon-reinforced ablation-resistant addition-curing silicone rubber composite material.

[0046] Comparative Example 1

[0047] The formula, by weight parts, is as follows: 100 parts vinyl 107 silicone rubber (viscosity 12000 mPa·s, vinyl content 1.0%), 10 parts fumed silica (average particle size 20 nm), 10 parts hexagonal boron nitride (average particle size 5 μm), 20 parts alumina (average particle size 2 μm), 15 parts zirconium oxide (average particle size 2 μm), 10 parts silicon carbide (average particle size 5 μm), 15 parts hollow glass microspheres (average particle size 50 μm), 10 parts hydrogen-containing silicone oil (viscosity 200 mPa·s, Si-H content 1.1 wt%), 0.3 parts 2-methyl-3-butyn-2-ol, and 0.5 parts Karstedt catalyst.

[0048] Includes the following steps:

[0049] Vinyl 107 silicone rubber, fumed silica, hexagonal boron nitride, alumina, zirconium oxide, silicon carbide, and hollow glass microspheres were mixed with a 2-methyl-3-butyn-2-ol inhibitor and stirred at room temperature until homogeneous. Hydrogen-containing silicone oil and Karstedt catalyst were added to the rubber compound and mixed until homogeneous. The compound was then uniformly coated into a mold and cured at 120°C under normal pressure for 6 hours to obtain the composite material.

[0050] The performance of the vinyl hyperbranched organosilicon-reinforced ablation-resistant addition-type silicone rubber composites prepared in Examples 1-2 and Comparative Example 1 were tested. The results are shown in Table 1 and 2. Figure 2-3 .

[0051] 1. Tensile strength test: The tensile strength of the rubber was tested using an Instron 5967 universal tensile testing machine;

[0052] 2. Thermogravimetric analysis test: Thermogravimetric analysis was performed using a STA449F3 thermogravimetric-differential scanning calorimetry analyzer (Netzche GmbH, Germany).

[0053] Table 1. Performance tests of vinyl hyperbranched organosilicon-reinforced ablation-resistant addition-type silicone rubber composites prepared in Examples 1-2 and Comparative Example 1.

[0054]

[0055] From Table 1 and Figure 2-3 It can be seen that the tensile strength of the addition-type silicone rubber composite material based on vinyl hyperbranched organosilicon reinforced with temperature resistance and ablation resistance prepared by the present invention is significantly improved. The strength of Example 2 reaches a maximum of 4.2 MPa, which is 107% higher than that of Comparative Example 1, and its elongation at break is also significantly improved. Compared with Comparative Example 1, the temperature resistance is greatly improved, with the initial thermal decomposition T90% increasing from 487.3℃ to over 590.0℃, and the residual weight increasing from 45.9% to 78.0%.

[0056] Depend on Figure 4 It can be seen that the addition-type silicone rubber composite material based on vinyl hyperbranched organosilicon reinforced with high temperature resistance and ablation resistance prepared by the present invention can significantly improve the ablation resistance. After flame ablation at 1500℃ for 30 min, the surface carbon layer is intact and dense, while the carbon layer of Comparative Example 1 is loose and has a large area of ​​peeling off after ablation under the same conditions.

[0057] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A vinyl-based hyperbranched organosilicon-reinforced addition-type silicone rubber composite material, characterized in that, It is composed of the following components by weight: 100 parts vinyl silicone rubber, 5-40 parts vinyl hyperbranched organosilicon, 5-20 parts fumed silica, 5-20 parts hexagonal boron nitride, 5-30 parts hollow glass microspheres, 5-40 parts alumina, 5-40 parts zirconium oxide, 5-20 parts silicon carbide, 2-30 parts hydrogen-containing silicone oil, 0.1-2 parts platinum catalyst, and 0.1-1 parts alkynol inhibitor.

2. The vinyl-based hyperbranched organosilicon-reinforced addition-type silicone rubber composite material according to claim 1, characterized in that, It is composed of the following components in parts by weight: 100 parts vinyl silicone rubber, 30 parts vinyl hyperbranched organosilicon, 15 parts fumed silica, 15 parts hexagonal boron nitride, 20 parts hollow glass microspheres, 30 parts alumina, 25 parts zirconium oxide, 15 parts silicon carbide, 15 parts hydrogen-containing silicone oil, 1 part platinum catalyst, and 0.5 parts alkynol inhibitor.

3. The vinyl hyperbranched organosilicon-reinforced addition-type silicone rubber composite material according to claim 1, characterized in that: The vinyl silicone rubber has a viscosity of 5000-20000 mPa·s and a vinyl mass fraction of 0.1%-3%; the vinyl hyperbranched silicone resin has a viscosity of 300-1000 mPa·s and a vinyl content of 5-10%.

4. The vinyl-based hyperbranched organosilicon-reinforced addition-type silicone rubber composite material according to claim 1, characterized in that: The average particle size of the fumed silica is 10-50 nm, the average particle size of the hexagonal boron nitride is 1-10 μm, the average particle size of the alumina is 1-5 μm, the average particle size of the zirconium oxide is 1-5 μm, the average particle size of the silicon carbide is 1-10 μm, and the average particle size of the hollow glass microspheres is 20-100 μm.

5. The vinyl hyperbranched organosilicon-reinforced addition-type silicone rubber composite material according to claim 1, characterized in that: The platinum catalyst is selected from one or more of the following: Karstedt catalyst, chloroplatinic acid, and chloroplatinum-divinyltetramethyldisiloxane complex.

6. The vinyl hyperbranched organosilicon-reinforced addition-type silicone rubber composite material according to claim 1, characterized in that: The alkynol inhibitor is selected from one or more of 2-methyl-3-butyn-2-ol, 1-ethynylcyclohexanol, 3-methyl-1-butyn-3-ol, and 3,5-dimethyl-1-hexyn-3-ol.

7. The vinyl hyperbranched organosilicon-reinforced addition-type silicone rubber composite material according to claim 1, characterized in that: The hydrogen-containing silicone oil has a viscosity of 100-1000 mPa·s and a Si-H content of 0.5-1.6 wt%.

8. The method for preparing the addition-type silicone rubber composite material based on vinyl hyperbranched organosilicon reinforcement with high temperature resistance and ablation resistance as described in any one of claims 1 to 7, characterized in that: Includes the following steps: 1) Add the vinyl hyperbranched silicone to the vinyl silicone rubber and mix thoroughly; 2) Add fumed silica, boron nitride, alumina, zirconium oxide, silicon carbide and hollow glass microspheres, and add alkynyl alcohol inhibitors and mix evenly. 3) After the system has cooled, add hydrogen-containing silicone oil and platinum catalyst and mix. 4) Apply the adhesive to the surface of the substrate or mold and cure it to obtain an ablation-resistant silicone rubber composite material.

9. The method for preparing the addition-type silicone rubber composite material based on vinyl hyperbranched organosilicon reinforcement with high temperature resistance and ablation resistance according to claim 8, characterized in that: In step 4), the curing temperature is 100-130℃ and the curing time is 4-8h.

10. The application of the vinyl-based hyperbranched organosilicon-reinforced temperature-resistant and ablation-resistant addition-type silicone rubber composite material according to any one of claims 1 to 7 in ablation-resistant protective materials, characterized in that: This includes engine heat insulation layers, aerospace thermal protection structures, ablation-resistant sealing materials, and high-temperature heat insulation coatings.

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