CN114958001B - A kind of high-strength ablation-resistant silicone rubber and its preparation method - Google Patents

Abstract

The invention relates to a high-strength ablation-resistant silicone rubber and a preparation method thereof, belonging to the technical field of silicone rubber. The raw materials of the high-strength ablation-resistant silicone rubber of the present invention include: 50 parts by weight of component A, 50 parts by weight of component B, 10-15 parts by weight of a mixture of decabromodiphenyl ether and antimony trioxide, 2-5 parts by weight of mixed fillers, 0.5-1 part by weight of hollow phenolic microspheres, 1-3 parts by weight of iron red, 3-5 parts by weight of fumed silica and 2-3 parts by weight of azodicarbonamide. The invention uses liquid T7-POSS organic silicon polymer as a filler, which can ensure that the liquid T7-POSS organic silicon polymer is uniformly dispersed when mixed with raw silicone rubber, effectively reduces the shrinkage rate of the silicone rubber after heating and curing, and simultaneously improves the ablation resistance of the silicone rubber.

Description

A kind of high-strength ablation-resistant silicone rubber and its preparation method

technical field

The invention belongs to the technical field of silicone rubber, and in particular relates to a high-strength ablation-resistant silicone rubber and a preparation method thereof.

Background technique

Silicone rubber is an elastomer material with a three-dimensional network structure formed after the crosslinking reaction of linear polysiloxane, and has a unique organic-inorganic hybrid molecular chain structure. According to different vulcanization mechanisms, silicone rubber can be divided into three categories: room temperature vulcanization type, heating vulcanization type and addition reaction type. Among them, the addition reaction silicone rubber can be used for a long time in the temperature range of -65 ° C to 200 ° C, and can maintain its soft and elastic properties, and has excellent electrical properties and chemical stability, and has weather resistance, water resistance, and ozone resistance.

Fire-resistant silicone rubber is currently widely used as a sealing material. In addition to requiring good flame-retardant properties of silicone rubber, higher requirements are also placed on the ablation resistance of silicone rubber. It is required that the material will not be burned through under the impact of extremely high temperature flames, and that it can form a carbonized heat insulation layer to protect the back parts from being damaged by strong heat impact. It also requires high strength to ensure that it will not be damaged during use.

Silicone rubber matrix resin is easy to be heated and deformed under flame burning at 1050-1100°C. In order to improve its ablation resistance, most of the existing technologies adopt the method of adding inorganic particles with heat insulation and reinforcing properties to silicone rubber. For example, Khristopher of Dow Corning Company adds 7%-20% wollastonite and 10%-60% reinforcing filler to liquid silicone rubber to make a test piece with a thickness of 0.635cm in Bunsen Burner 1093 Burning under the flame of ℃ for 15 minutes, the back side did not burn through or burn. However, the existing silicone rubber matrix resin still has the following technical problems: (1) Since the inorganic particles in the silicone rubber exceed a certain content, they will agglomerate, so the amount of addition is limited, and the material strength and ablation resistance cannot be greatly improved; (2) Under flame burning at 1050-1100 °C, the formed carbonized ceramic layer is relatively stable in a static state, but it is easy to fall off under vibration conditions, and cannot protect the back part well; (3) The density and toxicity are relatively large; not good.

Contents of the invention

In view of this, in order to solve the above technical problems, the present invention provides a high-strength ablation-resistant silicone rubber and a preparation method thereof.

The technical scheme adopted by the present invention to solve the above-mentioned technical problems is as follows.

The invention also provides a high-strength ablation-resistant silicone rubber. The raw materials include: 50 parts by weight of component A, 50 parts by weight of component B, 10-15 parts by weight of a mixture of decabromodiphenyl ether and antimony trioxide, 2-5 parts by weight of mixed fillers, 0.5-1 part by weight of hollow phenolic microspheres, 1-3 parts by weight of iron red, 3-5 parts by weight of fumed silica and 2-3 parts by weight of azodicarbonamide.

The mixed filler is a mixture of zirconia, rare earth doped oxides and hollow ceramic microspheres;

In parts by weight, the A component is composed of 30-80 parts of T7-POSS organosilicon polymer and 20-30 parts of methyl vinyl silicone oil, and the B component is composed of 20-80 parts of palladium catalyst and 5-20 parts of hydrogen-containing silicone oil;

The structural formula of the T7-POSS organosilicon polymer is as follows:

In the formula, R is isobutyl or cyclohexyl;

The average molecular weight of the T7-POSS organosilicon polymer is 1100-120000.

Preferably, in the mixture of decabromodiphenyl ether and antimony trioxide, decabromodiphenyl ether accounts for 70-75 wt%, and antimony trioxide accounts for 25-30 wt%.

Preferably, the mixed filler is a mixture of zirconia, rare earth doped oxide and hollow ceramic microspheres with a mass ratio of 1:1:1.

Preferably, the rare earth-doped oxide is light yellow granular, with a specific gravity ≤ 1.15g/cm ³ , a particle size of 120-180 μm, and a softening point ≥ 120°C.

Preferably, the particle size of the hollow ceramic microspheres is 80-120 mesh.

Preferably, the preparation method of the T7-POSS organosilicon polymer comprises the following steps:

1) The preparation method of vinyl methyl silicone

Dissolve methylphenyldimethoxysilane, methylvinyl silicone oil and dimethyldimethoxysilane in an organic solvent, stir evenly, add potassium hydroxide, heat to reflux for reaction, cool down to room temperature after the reaction is completed, filter to remove unreacted potassium hydroxide, distill under reduced pressure to remove the organic solvent, and dry in vacuum to obtain vinylmethyl silicone;

2) The preparation method of incompletely condensed cyclohexyltrisilanol

Under the protection of an inert atmosphere, add the reactants dropwise to a device equipped with lithium hydroxide monohydrate, deionized water, and an organic solvent. After the dropwise addition is completed, heat to reflux for reaction, drop to room temperature, add concentrated hydrochloric acid to acidify, filter with suction, wash the product with water to neutrality, wash with acetonitrile to obtain a white solid, and dry it in vacuum to obtain incompletely condensed cyclohexyltrisilanol;

3) The preparation method of T7-POSS organosilicon polymer

Dissolving the incompletely condensed cyclohexyltrisilanol prepared in step 2) and the vinylmethyl silicone prepared in step 1) in an organic solvent, heating to reflux for reaction, cooling to room temperature after the reaction, distilling off the organic solvent under reduced pressure, and drying in vacuum to obtain a T7-POSS organosilicon polymer.

More preferably,

In the step 1), the mass ratio of methylphenyldimethoxysilane, methylvinyl silicone oil, dimethyldimethoxysilane and potassium hydroxide is 2:1:2:0.4;

In said step 2), the reactant is isobutyltrimethoxysilane or cyclohexyltrimethoxysilane, and the mass ratio of lithium hydroxide monohydrate and the reactant is 3.3:20;

In the step 3), the mass ratio of incompletely condensed cyclohexyltrisilanol to vinylmethyl silicone polymer is 1:3.

More preferably,

In the step 1), the heating and reflux reaction is reflux at 85° C. for 10 h;

In the step 2), the heating and reflux reaction is reflux at 65° C. for 14 hours, and the acidification time is 2 hours;

In the step 3), the heating and reflux reaction is reflux at 90°C for 6h.

Preferably, in parts by weight, component A consists of 30-80 parts of T7-POSS organosilicon polymer mixed uniformly with 25-30 parts of methyl vinyl silicone oil, and component B consists of 20-80 parts of palladium catalyst mixed with 5-20 parts of hydrogen-containing silicone oil.

The present invention also provides a preparation method of the above-mentioned high-strength ablation-resistant silicone rubber, the steps are as follows:

Each component is weighed according to the proportion, mixed evenly, placed in a mold, pressurized, heated and vulcanized to obtain a high-strength ablation-resistant silicone rubber.

Preferably, decabromodiphenyl ether, antimony trioxide, zirconia, rare earth doped oxides, hollow ceramic microspheres, hollow phenolic microspheres, iron red, fumed silica, and azodicarbonamide are all dried before weighing each component.

Preferably, the components are mixed uniformly using a three-roll mill.

Preferably, the vulcanization temperature is 160±10° C., the vulcanization pressure is 5-10 MPa, and the vulcanization time is 20-30 minutes.

Compared with prior art, the beneficial effect of the present invention is:

The T7-POSS organosilicon polymer of the present invention is in a liquid state at room temperature, can be evenly mixed with raw silicone rubber, and can participate in the cross-linked network of silicone rubber without restriction, greatly reducing the shrinkage rate of the silicone rubber during curing, and at the same time improving the ablation resistance of the cured silicone rubber, and maximizing the role of the T7-POSS organosilicon polymer in reducing the curing shrinkage rate of silicone rubber and improving the ablation resistance of silicone rubber.

The invention uses liquid T7-POSS organic silicon polymer as a filler, which can ensure that the T7-POSS organic silicon polymer is evenly dispersed when mixed with raw silicone rubber, can effectively reduce the shrinkage rate of the silicone rubber after heating and curing, and simultaneously improve the ablation resistance of the silicone rubber. After testing, the high-strength ablation-resistant silicone rubber of the present invention has room temperature tensile strength: ≥6.5Mpa; volatile matter content (%): ≥99; pot life: ≥3h; specific gravity: 0.83～1.4g/ ^cm3 ; Shore A hardness after 14 days: ≥70; Fireproof and heat insulation performance: After 1093℃×15min, the film will not be burned through, and the temperature of the cold surface is lower than 350℃.

Detailed ways

In order to further understand the present invention, the preferred embodiments of the present invention are described below, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

The raw materials of the high-strength ablation-resistant silicone rubber of the present invention include: 50 parts by weight of component A, 50 parts by weight of component B, 10-15 parts by weight of a mixture of decabromodiphenyl ether and antimony trioxide, 2-5 parts by weight of mixed fillers, 0.5-1 parts by weight of hollow phenolic microspheres, 1-3 parts by weight of iron red, 3-5 parts by weight of fumed silica and 2-3 parts by weight of azodicarbonamide;

In parts by weight, the A component is composed of 30-80 parts of T7-POSS organosilicon polymer and 20-30 parts of methyl vinyl silicone oil, and the B component is composed of 20-80 parts of palladium catalyst and 5-20 parts of hydrogen-containing silicone oil;

Wherein, the structural formula of T7-POSS organosilicon polymer is as follows:

In the formula, R is isobutyl or cyclohexyl;

The average molecular weight of T7-POSS organosilicon polymer is 1100-120000.

In the above technical solution, in the mixture of decabromodiphenyl ether and antimony trioxide, decabromodiphenyl ether accounts for 70-75 wt%, and antimony trioxide accounts for 25-30 wt%.

In the above technical solution, the mixed filler is a mixture of zirconia, rare earth doped oxide and hollow ceramic microspheres with a mass ratio of 1:1:1; the particle size of the hollow ceramic microspheres is 80-120 mesh. The rare earth doped oxide is light yellow granular, specific gravity ≤ 1.15g/cm ³ , particle size 120-180μm, softening point ≥ 120°C.

In the above technical solution, T7-POSS organosilicon polymer is in liquid state at room temperature, can be evenly mixed with silicone rubber raw rubber, and can participate in the cross-linked network of silicone rubber without restriction, greatly reducing the shrinkage rate of silicone rubber during curing, and at the same time improving the ablation resistance of cured silicone rubber, maximizing the role of T7-POSS organosilicon polymer in reducing the curing shrinkage rate of silicone rubber and improving the ablation resistance of silicone rubber. The present invention provides a kind of preparation method of T7-POSS organosilicon polymer, but not limited thereto, comprises the following steps:

1) The preparation method of vinyl methyl silicone

Dissolve 100g of methylphenyldimethoxysilane, 50g of methylvinyl silicone oil and 100g of dimethyldimethoxysilane in toluene and stir for 15 minutes. Add 20g of potassium hydroxide and raise the temperature of the system to 85°C. After stirring and refluxing for 10 hours, cool down to room temperature. Remove unreacted potassium hydroxide by filtration, remove toluene by distillation under reduced pressure, and vacuum-dry at 40°C for 24 hours to obtain a transparent semi-solid material, namely vinylmethyl silicone, with a yield of about 85%.

2) The preparation method of incompletely condensed cyclohexyltrisilanol

Weighed 3.3g of lithium hydroxide monohydrate and 1.27g of deionized water (total water content 2.67g) into a 500mL three-necked flask, added 165mL of acetone+methanol (88vol.%+12vol.%) mixed solvent, under nitrogen protection, slowly added 20g of cyclohexyltrimethoxysilane or isobutyltrimethoxysilane, then heated up to 65°C, stirred for 14h, then stopped heating, cooled to room temperature, and added concentrated hydrochloric acid ( 1mol/L) 150mL acidified, stirred for 2h, after the acidification treatment, stopped the reaction, suction filtered, washed the product with water to neutrality, and then washed three times with acetonitrile to obtain a white solid, dried in vacuum at 35°C for 48h to obtain incompletely condensed cyclohexyltrisilanol (T7-POSS), with a yield of about 60%.

3) The preparation method of T7-POSS organosilicon polymer

Dissolve 50 g of the incompletely condensed cyclohexyltrisilanol (T7-POSS) prepared in step 2) and 150 g of the vinylmethyl silicone polymer prepared in step 1) in 500 mL of toluene, raise the temperature to 90° C., stir and reflux for 6 h, cool to room temperature, distill the toluene off under reduced pressure, and dry in vacuum at 40° C. for 4 h to obtain T7-POSS organosilicon polymer with a yield of about 91%.

The synthetic route of T7-POSS organosilicon polymer of the present invention is:

In the above technical solution, in parts by weight, preferably component A is composed of 30-80 parts of T7-POSS organosilicon polymer and 25-30 parts of methyl vinyl silicone oil, and preferably component B is composed of 20-80 parts of palladium catalyst and 5-20 parts of hydrogen-containing silicone oil. More preferably, component A consists of 80 parts of T7-POSS organosilicon polymer mixed with 20 parts of methyl vinyl silicone oil; component B consists of 80 parts of palladium catalyst mixed with 5 parts of hydrogen-containing silicone oil; or, component A consists of 30 parts of T7-POSS organosilicon polymer mixed with 30 parts of methyl vinyl silicone oil, and component B consists of 20 parts of palladium catalyst mixed with 20 parts of hydrogen-containing silicone oil; Component B is composed of 70 parts of palladium catalyst and 15 parts of hydrogen-containing silicone oil; or, component A is composed of 70 parts of T7-POSS silicone polymer and 25 parts of methyl vinyl silicone oil, and component B is composed of 80 parts of palladium catalyst and 10 parts of hydrogen-containing silicone oil.

The present invention also provides a preparation method of the above-mentioned high-strength ablation-resistant silicone rubber, the steps are as follows:

Each component is weighed according to the proportion, mixed evenly, placed in a mold, pressurized, heated and vulcanized to obtain a high-strength ablation-resistant silicone rubber.

In the above technical solution, it is preferable to use a three-roll mill to mix components A and B evenly.

In the above technical solution, the curing temperature is preferably 160±10° C., the curing pressure is preferably 5-10 MPa, and the curing time is preferably 20-30 minutes.

In the above technical solution, before weighing each component, it is preferable to dry decabromodiphenyl ether, antimony trioxide, zirconia, rare earth doped oxides, hollow ceramic microspheres, hollow phenolic microspheres, iron red, fumed silica, and azodicarbonamide. The preferred drying equipment is a blast box, the drying temperature is 110°C, and the drying time is 6 hours.

The invention uses liquid T7-POSS organic silicon polymer as a filler, which can ensure that the T7-POSS organic silicon polymer is evenly dispersed when mixed with raw silicone rubber, can effectively reduce the shrinkage rate of the silicone rubber after heating and curing, and simultaneously improve the ablation resistance of the silicone rubber. After testing, the high-strength ablation-resistant silicone rubber of the present invention has room temperature tensile strength: ≥6.5Mpa; volatile matter content (%): ≥99; pot life: ≥3h; specific gravity: 0.83～1.4g/ ^cm3 ; Shore A hardness after 14 days: ≥70; Fireproof and heat insulation performance: After 1093℃×15min, the film will not be burned through, and the temperature of the cold surface is lower than 350℃.

The terms used in the present invention generally have the meanings commonly understood by those skilled in the art, unless otherwise specified. In order to enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below in conjunction with embodiments.

In the following examples, various procedures and methods not described in detail are conventional methods well known in the art. The materials, reagents, devices, instruments, equipment, etc. used in the following examples can be obtained from commercial sources unless otherwise specified.

Below in conjunction with embodiment further illustrate the present invention.

Example 1

1) Put decabromodiphenyl ether, antimony trioxide, zirconia, rare earth doped oxides, hollow ceramic microspheres, hollow phenolic microspheres, iron red, fumed silica, and azodicarbonamide into a blast drying oven, and dry at 110°C for 6 hours;

2) In parts by weight, weigh 50 parts of component A, 50 parts of component B, 7 parts of decabromodiphenyl ether, 3 parts of antimony trioxide, 5 parts of mixed fillers (zirconia, rare earth doped oxides and hollow ceramic microspheres at a mass ratio of 1:1:1), 0.5 parts of hollow phenolic microspheres, 3 parts of iron red, 5 parts of fumed silica and 3 parts of azodicarbonamide, and add them to a three-roll mill, and grind and knead for 10 to 15 minutes until the powder filler is free of knots. Block the granules, and mix them with A component and B component thoroughly, put the obtained rubber into the mold, pressurize at 160±10°C at 5-10MPa, vulcanize for 20-30min, and obtain a 3.2mm thick high-strength ablation-resistant silicone rubber (film);

By weight: Component A is composed of 80 parts of T7-POSS silicone polymer (prepared according to the method in the specific embodiment) and 20 parts of methyl vinyl silicone oil; B component is composed of 80 parts of palladium catalyst and 5 parts of hydrogen-containing silicone oil (202 silicone oil).

Example 2

1) Put decabromodiphenyl ether, antimony trioxide, zirconia, rare earth doped oxides, hollow ceramic microspheres, hollow phenolic microspheres, iron red, fumed silica, and azodicarbonamide into a blast drying oven, and dry at 110°C for 6 hours;

2) In parts by weight, weigh 50 parts of component A, 50 parts of component B, 10.5 parts of decabromodiphenyl ether, 4.5 parts of antimony trioxide, 2 parts of mixed fillers (zirconia, rare earth doped oxides and hollow ceramic microspheres at a mass ratio of 1:1:1), 1 part of hollow phenolic microspheres, 1 part of iron red, 3 parts of fumed silica and 2 parts of azodicarbonamide, and add them to the three-roll mill, and grind and knead for 10-15 minutes until the powder becomes The filler has no agglomerated particles, and is completely mixed with components A and B. The obtained rubber is put into a mold, pressurized at 160±10°C at 5-10 MPa, and vulcanized for 20-30 minutes to obtain a high-strength ablation-resistant silicone rubber (film) with a thickness of 3.2mm;

By weight: Component A is composed of 30 parts of T7-POSS silicone polymer (prepared according to the method in the specific embodiment) and 30 parts of methyl vinyl silicone oil; B component is composed of 20 parts of palladium catalyst and 20 parts of hydrogen-containing silicone oil (202 silicone oil).

Example 3

1) Put decabromodiphenyl ether, antimony trioxide, zirconia, rare earth doped oxides, hollow ceramic microspheres, hollow phenolic microspheres, iron red, fumed silica, and azodicarbonamide into a blast drying oven, and dry at 110°C for 6 hours;

2) In parts by weight, weigh 50 parts of component A, 50 parts of component B, 9 parts of decabromodiphenyl ether, 3 parts of antimony trioxide, 3 parts of mixed fillers (zirconia, rare earth doped oxides and hollow ceramic microspheres at a mass ratio of 1:1:1), 1 part of hollow phenolic microspheres, 2 parts of iron red, 4 parts of fumed silica, and 3 parts of azodicarbonamide, and add them to the three-roll mill, and grind and mix for 10-15 minutes until the powder filler has no agglomerated particles , and completely mixed with components A and B, put the obtained rubber into a mold, pressurize at 160±10°C at 5-10MPa, vulcanize for 20-30min, and obtain a 3.2mm thick high-strength ablation-resistant silicone rubber (film);

By weight: Component A is composed of 70 parts of T7-POSS silicone polymer (prepared according to the method in the specific embodiment) and 30 parts of methyl vinyl silicone oil; B component is composed of 70 parts of palladium catalyst and 15 parts of hydrogen-containing silicone oil (202 silicone oil).

Example 4

1) Put decabromodiphenyl ether, antimony trioxide, zirconia, rare earth doped oxides, hollow ceramic microspheres, hollow phenolic microspheres, iron red, fumed silica, and azodicarbonamide into a blast drying oven, and dry at 110°C for 6 hours;

2) In parts by weight, weigh 50 parts of component A, 50 parts of component B, 7 parts of decabromodiphenyl ether, 3 parts of antimony trioxide, 3 parts of mixed fillers (zirconia, rare earth doped oxides and hollow ceramic microspheres with a mass ratio of 1:1:1), 0.5 parts of hollow phenolic microspheres, 1 part of iron red, 4 parts of fumed silica and 3 parts of azodicarbonamide, and add them to a three-roll mill, and grind and knead for 10 to 15 minutes until the powder filler is free of knots. Block the granules, and mix them with A component and B component thoroughly, put the obtained rubber into the mold, pressurize at 160±10°C at 5-10MPa, vulcanize for 20-30min, and obtain a 3.2mm thick high-strength ablation-resistant silicone rubber (film);

By weight: Component A is composed of 70 parts of T7-POSS silicone polymer (prepared according to the method in the specific embodiment) and 25 parts of methyl vinyl silicone oil; B component is composed of 80 parts of palladium catalyst and 10 parts of hydrogen-containing silicone oil (202 silicone oil).

The properties of the high-strength ablation-resistant silicone rubber (film) of Examples 1 to 6 were tested. The test results are shown in Table 1.

Performance of the high-strength ablation-resistant silicone rubber (film) of Table 1 Embodiment 1 to Embodiment 6

As can be seen from Table 1, the present invention uses liquid T7-POSS organosilicon polymer as a filler, which can ensure that the T7-POSS organosilicon polymer is uniformly dispersed when mixed with raw silicone rubber, can effectively reduce the shrinkage rate of silicone rubber after heating and curing, and simultaneously improve the ablation resistance of silicone rubber. After testing, the high-strength ablation-resistant silicone rubber of the present invention has room temperature tensile strength: ≥6.5Mpa; volatile matter content (%): ≥99; pot life: ≥3h; specific gravity: 0.83～1.4g/ ^cm3 ; Shore A hardness after 14 days: ≥70; Fireproof and heat insulation performance: After 1093℃×15min, the film will not be burned through, and the temperature of the cold surface is lower than 350℃.

The upper and lower limits and interval values of each raw material of the present invention and the upper and lower limits and interval values of process parameters (time, temperature, etc.) can all realize the present invention, and the embodiments are not enumerated here.

Apparently, the above-mentioned implementation manners are only examples for clear description, rather than limiting the embodiments. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. It is not necessary and impossible to exhaustively list all the embodiments here. However, the obvious changes or changes derived therefrom are still within the scope of protection of the present invention.

Claims (10)

1. High-strength ablation-resistant silicone rubber, characterized in that the raw materials include: 50 parts by weight of component A, 50 parts by weight of component B, 10-15 parts by weight of a mixture of decabromodiphenyl ether and antimony trioxide, 2-5 parts by weight of mixed fillers, 0.5-1 parts by weight of hollow phenolic microspheres, 1-3 parts by weight of iron red, 3-5 parts by weight of fumed silica and 2-3 parts by weight of azodicarbonamide; The mixed filler is a mixture of zirconia, rare earth doped oxides and hollow ceramic microspheres; In parts by weight, the A component is composed of 30-80 parts of T7-POSS organosilicon polymer and 20-30 parts of methyl vinyl silicone oil, and the B component is composed of 20-80 parts of palladium catalyst and 5-20 parts of hydrogen-containing silicone oil; The structural formula of the T7-POSS organosilicon polymer is as follows: In the formula, R is isobutyl or cyclohexyl; The average molecular weight of the T7-POSS organosilicon polymer is 1100-120000. 2. The high-strength ablation-resistant silicone rubber according to claim 1, characterized in that, in the mixture of decabromodiphenyl ether and antimony trioxide, decabromodiphenyl ether accounts for 70-75 wt%, and antimony trioxide accounts for 25-30 wt%. 3. The high-strength ablation-resistant silicone rubber according to claim 1, wherein the mixed filler is a mixture of zirconia, rare earth doped oxides and hollow ceramic microspheres with a mass ratio of 1:1:1; The rare earth doped oxide is light yellow granular, specific gravity ≤ 1.15g/cm ³ , particle size 120-180μm, softening point ≥ 120°C; The particle size of the hollow ceramic microspheres is 80-120 mesh. 4. The high-strength ablation-resistant silicone rubber according to claim 1, characterized in that, in parts by weight, component A is composed of 30-80 parts of T7-POSS organosilicon polymer and 25-30 parts of methyl vinyl silicone oil, and component B is composed of 20-80 parts of palladium catalyst and 5-20 parts of hydrogen-containing silicone oil. 5. The high-strength ablation-resistant silicone rubber according to claim 1, characterized in that, the preparation method of the T7-POSS organosilicon polymer comprises the following steps: 1) The preparation method of vinyl methyl silicone Dissolve methylphenyldimethoxysilane, methylvinyl silicone oil and dimethyldimethoxysilane in an organic solvent, stir evenly, add potassium hydroxide, heat to reflux for reaction, cool down to room temperature after the reaction is completed, filter to remove unreacted potassium hydroxide, distill under reduced pressure to remove the organic solvent, and dry in vacuum to obtain vinylmethyl silicone; 2) The preparation method of incompletely condensed cyclohexyltrisilanol Under the protection of an inert atmosphere, add the reactants dropwise to a device equipped with lithium hydroxide monohydrate, deionized water, and an organic solvent. After the dropwise addition is completed, heat to reflux for reaction, drop to room temperature, add concentrated hydrochloric acid to acidify, filter with suction, wash the product with water to neutrality, wash with acetonitrile to obtain a white solid, and dry it in vacuum to obtain incompletely condensed cyclohexyltrisilanol; 3) The preparation method of T7-POSS organosilicon polymer Dissolving the incompletely condensed cyclohexyltrisilanol prepared in step 2) and the vinylmethyl silicone prepared in step 1) in an organic solvent, heating to reflux for reaction, cooling to room temperature after the reaction, distilling off the organic solvent under reduced pressure, and drying in vacuum to obtain a T7-POSS organosilicon polymer. 6. The high-strength ablation-resistant silicone rubber according to claim 5, characterized in that, In the step 1), the mass ratio of methylphenyldimethoxysilane, methylvinyl silicone oil, dimethyldimethoxysilane and potassium hydroxide is 2:1:2:0.4; In said step 2), the reactant is isobutyltrimethoxysilane or cyclohexyltrimethoxysilane, and the mass ratio of lithium hydroxide monohydrate and the reactant is 3.3:20; In the step 3), the mass ratio of incompletely condensed cyclohexyltrisilanol to vinylmethyl silicone polymer is 1:3. 7. The high-strength ablation-resistant silicone rubber according to claim 5, characterized in that, In the step 1), the heating and reflux reaction is reflux at 85° C. for 10 h; In the step 2), the heating and reflux reaction is reflux at 65° C. for 14 hours, and the acidification time is 2 hours; In the step 3), the heating and reflux reaction is reflux at 90°C for 6h. 8. The preparation method of the high-strength ablation-resistant silicone rubber described in any one of claims 1 to 7, characterized in that the steps are as follows: Each component is weighed according to the proportion, mixed evenly, placed in a mold, pressurized, heated and vulcanized to obtain a high-strength ablation-resistant silicone rubber. 9. The preparation method of high-strength ablation-resistant silicone rubber according to claim 8, characterized in that, before weighing each component, decabromodiphenyl ether, antimony trioxide, zirconia, rare earth doped oxides, hollow ceramic microspheres, hollow phenolic microspheres, iron red, fumed silica, and azodicarbonamide are all dried. 10. the preparation method of high-strength ablation-resistant silicone rubber according to claim 8, is characterized in that, Use a three-roll mill to mix the components evenly; The vulcanization temperature is 160±10°C, the vulcanization pressure is 5-10MPa, and the vulcanization time is 20-30min.