1. A preparation method of ablation-resistant resin with low expansion coefficient is characterized by comprising the following steps:

(1) dissolving resin in an organic solvent to obtain a resin solution;

(2) under inert atmosphere, adding a modified catalyst into the resin solution, uniformly mixing, adding a modifier, and stirring to obtain modified resin;

(3) and adding an inorganic filler into the modified resin, and mixing to obtain the low-expansion-coefficient ablation-resistant resin.

2. The method of claim 1, wherein:

the resin is at least one of barium phenolic resin, ammonia phenolic resin, phosphorus phenolic resin, molybdenum phenolic resin, boron phenolic resin, benzoxazine resin, phenol triazine resin and polyaryl acetylene resin; and/or

The organic solvent is at least one of N, N-dimethylformamide, dimethyl sulfoxide, ethanol, isopropanol, tetramethylethylenediamine, N-butanol, dioxane, tetrahydrofuran and acetone.

3. The method of claim 1, wherein:

in the step (1), the mass ratio of the resin to the organic solvent is 0.5-1: 1.

4. The method of claim 1, wherein:

the modified catalyst is at least one of a silane coupling agent, a titanate coupling agent, a bimetallic coupling agent and a borate coupling agent; and/or

The modifier is at least one of aromatic phenolic resin, organic silicon resin and phenyl maleic acid imide resin.

5. The method of claim 1, wherein:

the modified catalyst is at least one of aminopropyltriethoxysilane and vinyl tri (2-methoxyethoxy) silane; and/or

The modifier is at least one of naphthol modified phenolic resin and methyl diphenyl vinyl silicon.

6. The method of claim 1, wherein:

the step (2) comprises the following substeps:

(21) adding a modified catalyst into the resin solution, stirring for 30-60min at 30-50 ℃, uniformly mixing, adding a modifier, and stirring for 60-120min at 60-80 ℃ to obtain a modified resin solution;

(22) and carrying out reduced pressure distillation on the modified resin solution to obtain the modified resin.

7. The method of claim 1, wherein:

the mass ratio of the modified catalyst to the organic solvent is 0.05-0.1: 1;

the mass ratio of the modifier to the organic solvent is 0.1-0.35: 1.

8. The method of claim 1, wherein:

the inorganic filler is ZrW₂O₈、Fe₂(MoO₄)₃、Zr₂(WO₄)(PO₄)₂、Zn(CN)₂、Cd(CN)₂At least one of; and/or

The mesh number of the inorganic filler is 600-800.

9. The production method according to any one of claims 1 to 8, characterized in that:

in the step (3), the mass ratio of the inorganic filler to the modified resin is 0.05-0.12: 1; and/or

In the step (3), the mixing temperature is 60-90 ℃, and the mixing time is 30-60 min.

10. An ablation-resistant resin with a low expansion coefficient, which is prepared by the preparation method of any one of claims 1 to 9; wherein the low expansion coefficient ablation-resistant resin has a thermal expansion coefficient of (1-4) x 10^－6The carbon residue rate is 70-80% at/° C.

Background

The ablation-resistant resin is an important component of an aircraft thermal protection material, takes an organic polymer as a matrix, and takes away heat to realize the thermal protection effect by utilizing the processes of pyrolysis desorption heat, carbon sublimation heat absorption, mass ejection of pyrolysis gas, radiation effect of a carbonization layer, carbide degradation and the like at high temperature.

The currently commonly used aircraft thermal protection resin material is high temperature resistant phenolic resin, and the temperature difference between the surface and the interior of the thermal protection member can reach 200-300 ℃ in the flight process, so that strong thermal stress is generated in the thermal protection member, and the thermal protection effect is influenced by the internal delamination cracking, bulging and the like.

The existing aircraft bearing structure is mainly obtained by adopting a composite design of a resin-based heat-proof structure and a carbon fiber cold structure, but because the difference of the thermal expansion coefficients between a resin matrix and a carbon fiber reinforced material is large, the temperature of a protective component is high, the thermal deformation of the thermal protective component is caused by severe temperature change, the carbon fiber reinforced material is hardly deformed, the interface failure of the aircraft bearing structure is easily caused, separation or cracking occurs, and the flight safety is seriously influenced.

Therefore, at present, a novel ablation-resistant resin with a low expansion coefficient is urgently needed, the problem of thermal protection failure caused by thermal stress in the flight process can be avoided, and the problem of interface matching between a thermal protection structure and a carbon fiber structure can be optimized.

Disclosure of Invention

The embodiment of the invention provides a low-expansion-coefficient ablation-resistant resin and a preparation method thereof, which can avoid the problem of thermal protection failure caused by thermal stress in the flight process, optimize the interface matching problem of a thermal protection structure and a carbon fiber cold structure and improve the stability of an aircraft.

In a first aspect, the present invention provides a method for preparing a low expansion coefficient ablation-resistant resin, comprising the steps of:

(1) dissolving resin in an organic solvent to obtain a resin solution;

(2) under inert atmosphere, adding a modified catalyst into the resin solution, uniformly mixing, adding a modifier, and stirring to obtain modified resin;

(3) and adding an inorganic filler into the modified resin, and mixing to obtain the low-expansion-coefficient ablation-resistant resin.

Preferably, the resin is at least one of barium phenolic resin, ammonia phenolic resin, phosphorus phenolic resin, molybdenum phenolic resin, boron phenolic resin, benzoxazine resin, phenol triazine resin and polyaryl acetylene resin.

Preferably, the organic solvent is at least one of N, N-dimethylformamide, dimethyl sulfoxide, ethanol, isopropanol, tetramethylethylenediamine, N-butanol, dioxane, tetrahydrofuran and acetone.

Preferably, in the step (1), the mass ratio of the resin to the organic solvent is 0.5-1: 1.

Preferably, the modified catalyst is at least one of a silane coupling agent, a titanate coupling agent, a bimetallic coupling agent and a borate coupling agent.

Preferably, the modifier is at least one of aromatic hydrocarbon-based phenolic resin, organic silicon resin and phenyl maleic acid imide resin.

More preferably, the modification catalyst is at least one of aminopropyltriethoxysilane and vinyltris (2-methoxyethoxy) silane.

More preferably, the modifier is at least one of naphthol modified phenolic resin and methyl bis phenyl vinyl silicon.

Preferably, step (2) comprises the sub-steps of:

(21) adding a modified catalyst into the resin solution, stirring for 30-60min at 30-50 ℃, uniformly mixing, adding a modifier, and stirring for 60-120min at 60-80 ℃ to obtain a modified resin solution;

(22) and carrying out reduced pressure distillation on the modified resin solution to obtain the modified resin.

Preferably, the mass ratio of the modified catalyst to the organic solvent is 0.05-0.1: 1;

the mass ratio of the modifier to the organic solvent is 0.1-0.35: 1.

Preferably, the inorganic filler is ZrW₂O₈、Fe₂(MoO₄)₃、Zr₂(WO₄)(PO₄)₂、Zn(CN)₂、Cd(CN)₂At least one of (1).

Preferably, the mesh number of the inorganic filler is 600-800.

Preferably, the mass ratio of the inorganic filler to the modified resin is 0.05-0.12: 1.

Preferably, in the step (3), the mixing temperature for mixing is 60-90 ℃ and the mixing time is 30-60 min.

In a second aspect, the invention provides a low expansion coefficient ablation-resistant resin prepared by any one of the preparation methods of the first aspect; preferably, the low expansion coefficient ablation resistant resin has a coefficient of thermal expansion of (1-4) x 10^－6The carbon residue rate is 70-80% at/° C.

Compared with the prior art, the invention at least has the following beneficial effects:

(1) the invention prepares the ablation-resistant resin with low expansion coefficient by modifying the molecular structure and adding modified fillers, so that the resin has ablation resistance, scouring resistance and low thermal expansion coefficient; wherein the coefficient of thermal expansion can be as low as (1-4). times.10^－6The carbon residue rate can be as high as 70-80 percent per DEG C. Therefore, the problem of internal thermal stress of the thermal protection material prepared from the low-expansion-coefficient ablation-resistant resin can be effectively solved, and the problem of thermal protection failure caused by thermal stress in the flight process is avoided; and the difference of the thermal expansion coefficients between the low-expansion-coefficient ablation-resistant resin and the carbon fiber reinforced material is small, so that the interface matching between the thermal protection structure and the carbon fiber structure is facilitatedIn addition, the aircraft bearing structure obtained by adopting the composite design of the low-expansion-coefficient ablation-resistant resin and the carbon fiber reinforced material is more stable, and the stability of the aircraft can be further improved.

(2) According to the invention, the modified resin is obtained by introducing the phenyl or silicon-based side chain into the high-temperature-resistant thermosetting resin by adding the modifier, the carbon residue rate of the modified resin is improved, the high-carbon-residue-rate resin generates few gaseous substances at high temperature, and the formed carbon layer can cover the surface of the high polymer to play a role in protection, so that the heat resistance and ablation resistance are improved.

(3) The ablation-resistant resin with the low expansion coefficient is obtained by adding the inorganic filler with the low expansion coefficient; meanwhile, the crystal structure of the inorganic filler is relatively stable, so that the inorganic filler can be decomposed in a thermal environment, an ablation-resistant effect is achieved, and the carbon residue rate of the low-expansion-coefficient ablation-resistant resin is further improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a schematic diagram of a preparation method of a low-expansion-coefficient ablation-resistant resin provided by the invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer and more complete, the technical solutions in the embodiments of the present invention will be described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention, and based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without creative efforts belong to the scope of the present invention.

As shown in fig. 1, a preparation method of a low expansion coefficient ablation-resistant resin provided by an embodiment of the present invention includes the following steps:

(1) dissolving resin in an organic solvent to obtain a resin solution;

(2) under inert atmosphere, adding a modified catalyst into the resin solution, uniformly mixing, adding a modifier, and stirring to obtain modified resin;

(3) and adding an inorganic filler into the modified resin, and mixing to obtain the low-expansion-coefficient ablation-resistant resin.

According to some preferred embodiments, the resin is at least one of a barium phenol-formaldehyde resin, an ammonia phenol-formaldehyde resin, a phosphorous phenol-formaldehyde resin, a molybdenum phenol-formaldehyde resin, a boron phenol-formaldehyde resin, a benzoxazine resin, a phenol triazine resin, and a polyarylacetylene resin.

At least one of them is a mixture of any one or any several of them mixed in any ratio. Wherein the adopted resin is thermosetting resin which has high heat resistance and is not easy to deform under pressure; the polyarylacetylene resin is a polymer obtained by addition polymerization using an ethynyl aromatic hydrocarbon (for example, m-diethynylbenzene, p-diethynylbenzene, diethynylbiphenyl, or the like) as a monomer.

According to some preferred embodiments, the organic solvent is at least one of N, N-dimethylformamide, dimethyl sulfoxide, ethanol, isopropanol, tetramethylethylenediamine, N-butanol, dioxane, tetrahydrofuran, acetone.

According to some preferred embodiments, in step (1), the mass ratio of the resin to the organic solvent is 0.5 to 1:1 (for example, may be 0.5:1, 0.55:1, 0.6:1, 0.65:1, 0.7:1, 0.75:1, 0.8:1, 0.85:1, 0.9:1, 0.95:1, or 1: 1).

According to some preferred embodiments, the modification catalyst is at least one of a silane coupling agent, a titanate coupling agent, a bimetallic coupling agent, a borate coupling agent.

For example, modifying catalysts include, but are not limited to, aminopropyltriethoxysilane, vinyltrimethylsilane, vinyltris (2-methoxyethoxy) silane, anilinomethyltrimethoxysilane, titanic acid coupling agent TMC-201, borate ester coupling agent LD-100P, zirconium-aluminum coupling agent LD-139.

According to some more preferred embodiments, the modifying catalyst is at least one of aminopropyltriethoxysilane, vinyltris (2-methoxyethoxy) silane.

According to some preferred embodiments, the modifier is at least one of an aromatic hydrocarbon-based phenol-formaldehyde resin, a silicone resin, a phenylmaleimide resin.

According to some more preferred embodiments, the modifier is at least one of naphthol modified phenolic resin, methyl bis phenyl vinyl silicon.

In the invention, the reaction of the resin and the modifier is catalyzed by the modified catalyst, and the phenyl or silicon-based side chain is introduced into the resin in a chemical mode to complete the modification of the resin, so that the carbon residue rate of the modified resin is further improved.

According to some more preferred embodiments, step (2) comprises the sub-steps of:

(21) adding a modified catalyst into the resin solution, stirring for 30-60min at 30-50 ℃, uniformly mixing, adding a modifier, and stirring for 60-120min at 60-80 ℃ to obtain a modified resin solution;

(22) and (2) distilling the modified resin solution under reduced pressure to obtain the modified resin catalyst, and adding the modified resin catalyst into the resin solution obtained in the step (1).

Experiments prove that the modified resin solution is obtained by stirring the mixture for 30 to 60min (for example, 30min, 35min, 40 ℃, 45 ℃ or 60min) under inert atmosphere (for example, nitrogen atmosphere or argon atmosphere) and 30 to 50 ℃ (for example, 30 ℃, 35 ℃, 40 ℃, 45 ℃ or 50 ℃), then adding the modifier and stirring the mixture for 60 to 120min (for example, 60min, 70min, 80min, 90min, 100min, 110min or 120min) under 60 to 80 ℃ (for example, 60 ℃, 65 ℃, 70 ℃, 75 ℃ or 80 ℃), and then distilling the modified resin solution under reduced pressure to obtain the modified resin; wherein when the content of the organic solvent remaining in the modified resin is not more than 10%, the reduced pressure distillation is stopped.

It should be noted that the heating temperature for the reduced pressure distillation in the step (2) is a temperature value not lower than the boiling point of the organic solvent. For example, when the organic solvent in step (1) is N, N-dimethylformamide, the heating temperature in step (2) is not lower than 153 ℃ of its boiling point (e.g., may be 158 ℃, 160 ℃, 163 ℃, or the like); when the organic solvent in the step (1) comprises dimethyl sulfoxide, the heating temperature of the step (2) is not lower than 189 ℃ of the boiling point thereof; when the organic solvent in step (1) comprises ethanol, the heating temperature in step (2) is not lower than 78 ℃ which is the boiling point thereof.

In the present invention, most of the organic solvent is removed by distillation under reduced pressure to obtain a modified resin.

According to some preferred embodiments, the mass ratio of the modification catalyst to the organic solvent is 0.05 to 0.1: 1;

the mass ratio of the modifier to the organic solvent is 0.1-0.35: 1.

Experiments prove that the mass ratio of the modified catalyst to the organic solvent is 0.05-0.1:1 (for example, 0.05:1, 0.06:1, 0.07:1, 0.08:1, 0.09:1 or 0.1:1), and the mass ratio of the modifier to the organic solvent is 0.1-0.35:1 (for example, 0.1:1, 0.15:1, 0.2:1, 0.25:1, 0.3:1 or 0.35: 1).

According to some preferred embodiments, the inorganic filler is ZrW₂O₈、Fe₂(MoO₄)₃、Zr₂(WO₄)(PO₄)₂、Zn(CN)₂、Cd(CN)₂At least one of (1).

In the invention, the selected inorganic fillers have low thermal expansion coefficient or negative thermal expansion coefficient, and the thermal expansion coefficient of the resin can be reduced after the inorganic fillers are added; and the crystal structure of the inorganic filler is relatively stable, the inorganic filler can be decomposed in a thermal environment, an anti-ablation effect is achieved, and the carbon residue rate of the prepared low-expansion-coefficient ablation-resistant resin is further improved.

According to some preferred embodiments, the mesh size of the inorganic filler is 600-800.

In the present invention, in order to uniformly disperse the inorganic filler in the modified resin, the inorganic filler needs to be ground in advance so that the mesh number of the inorganic filler is 600-800, which is sufficient for the function of the inorganic filler.

According to some preferred embodiments, the mass ratio of the inorganic filler to the modified resin is 0.05 to 0.12:1 (e.g., may be 0.05:1, 0.06:1, 0.07:1, 0.08:1, 0.09:1, 0.1:1, 0.11:1, or 0.12: 1).

According to some preferred embodiments, in the step (3), the mixing temperature for mixing is 60 to 90 ℃ (for example, 60 ℃, 65 ℃, 70 ℃, 75 ℃, 80 ℃, 85 ℃ or 90 ℃), and the mixing time is 30 to 60min (for example, 30min, 35min, 40min, 45min, 50min, 55min or 60 min).

The mixing equipment used in the mixing treatment is not particularly limited, and an open mill can be used, and an internal mixer or other equipment can be used.

The invention also provides a low-expansion-coefficient ablation-resistant resin which is prepared by the preparation method provided by the invention; preferably, the low expansion coefficient ablation resistant resin has a coefficient of thermal expansion of (1-4) x 10^－6The carbon residue rate is 70-80% at/° C.

In the present invention, the thermal expansion coefficient of the ablation resistant resin having a low thermal expansion coefficient may be as low as (1-10). times.10^－6/° C, but is preferably (1-4). times.10^－6/℃。

In order to more clearly illustrate the technical solution and advantages of the present invention, the following examples are provided to describe the preparation method of the low expansion coefficient ablation resistant resin of the present invention in detail.

In the following examples: the mass of the resin, the organic solvent, the modified catalyst, the modifier, the inorganic filler and the modified resin are all expressed in parts by weight;

the naphthol modified phenolic resin is purchased from NPR-68 of northwest university of industry;

the borate ester coupling agent LD-100P was purchased from Cilida resins, Inc., of Yangzhou;

the polyarylacetylene resin is obtained by polymerizing p-diethynylbenzene as a monomer.

Example 1

(1) Dissolving 50 parts of resin (boron phenolic resin) in 100 parts of organic solvent (a mixed solution of ethanol and dimethyl sulfoxide in a volume ratio of 1:1) to obtain a resin solution;

(2) under inert atmosphere, adding 5 parts of modified catalyst (aminopropyltriethoxysilane) into the resin solution, stirring for 30min at 30 ℃, uniformly mixing, then adding 15 parts of modifier (naphthol modified phenolic resin), stirring for 100min at 60 ℃, and stirring to obtain a modified resin solution;

distilling the modified resin solution under reduced pressure at 195 ℃ (i.e. not lower than the temperature of any boiling point of ethanol and dimethyl sulfoxide), and stopping distilling under reduced pressure until the content of the residual organic solvent in the modified resin is 8% to obtain the modified resin;

(3) mixing 8 parts of inorganic filler (ZrW)₂O₈600 mesh) is added into 100 parts of the modified resin, and then the mixture is mixed for 60min at 70 ℃ to obtain the low-expansion-coefficient ablation-resistant resin.

In this embodiment, it is preferable to use a mixed organic solvent so as to ensure sufficient dissolution of the resin.

Example 2

(1) Dissolving 50 parts of resin (boron phenolic resin) in 100 parts of organic solvent (mixed solution of acetone and dioxane in a volume ratio of 1:1) to obtain a resin solution;

(2) adding 10 parts of modified catalyst (5 parts of aminopropyltriethoxysilane and 5 parts of borate coupling agent LD-100P) into the resin solution under inert atmosphere, stirring for 30min at 30 ℃, uniformly mixing, adding 15 parts of modifier (phenylmaleimide resin), stirring for 100min at 60 ℃, and stirring to obtain a modified resin solution;

carrying out reduced pressure distillation on the modified resin solution at 110 ℃ (namely the temperature is not lower than any boiling point of acetone and dioxane), and stopping reduced pressure distillation when the content of the residual organic solvent in the modified resin is 10% to obtain the modified resin;

(3) mixing 8 parts of inorganic filler (ZrW)₂O₈600 mesh) is added into 100 parts of the modified resin, and then the mixture is mixed for 60min at 70 ℃ to obtain the low-expansion-coefficient ablation-resistant resin.

Example 3

(1) Dissolving 100 parts of resin (benzoxazine resin) in 100 parts of organic solvent (mixed solution of ethanol and tetramethylethylenediamine in a volume ratio of 1: 2) to obtain a resin solution;

(2) adding 10 parts of modified catalyst (5 parts of aminopropyltriethoxysilane and 5 parts of zirconium-aluminum coupling agent LD-139) into the resin solution under inert atmosphere, stirring for 30min at 50 ℃, uniformly mixing, adding 20 parts of modifier (methyl bis phenyl vinyl silicon), stirring for 60min at 80 ℃, and stirring to obtain a modified resin solution;

distilling the modified resin solution under reduced pressure at 130 ℃ (i.e. at a temperature not lower than any boiling point of ethanol and tetramethylethylenediamine) until the content of the residual organic solvent in the modified resin is 5%, and stopping distilling under reduced pressure to obtain the modified resin;

(3) 12 parts of inorganic filler (Fe)₂(MoO₄)₃Mesh number of 800) is added into 100 parts of the modified resin, and then the mixture is mixed for 30min at 80 ℃ to obtain the low-expansion-coefficient ablation-resistant resin.

Example 4

(1) Dissolving 60 parts of resin (phenol triazine resin) in 100 parts of an organic solvent (a mixed solution of ethanol and isopropanol in a volume ratio of 1:1) to obtain a resin solution;

(2) adding 8 parts of modified catalyst (vinyl tri (2-methoxyethoxy) silane) into the resin solution under inert atmosphere, stirring for 30min at 40 ℃, uniformly mixing, adding 25 parts of modifier (naphthol modified phenolic resin), stirring for 80min at 70 ℃, and stirring to obtain modified resin solution;

distilling the modified resin solution under reduced pressure at 90 ℃ (i.e. at a temperature not lower than any boiling point of ethanol and isopropanol) until the content of the residual organic solvent in the modified resin is 9%, and stopping distilling under reduced pressure to obtain the modified resin;

(3) 10 parts of an inorganic filler (Zr)₂(WO₄)(PO₄)₂700 mesh) was added to 100 parts of the modified resin, and then kneaded at 60 ℃ for 60 minutes to obtain the ablation-resistant resin having a low expansion coefficient.

Example 5

(1) Dissolving 100 parts of resin (polyarylacetylene resin) in 100 parts of organic solvent (mixed solution of tetrahydrofuran and n-butanol in a volume ratio of 1: 4) to obtain a resin solution;

(2) under an inert atmosphere, adding 5 parts of a modified catalyst (titanic acid coupling agent TMC-201) into the resin solution, stirring for 30min at 45 ℃, uniformly mixing, then adding 10 parts of a modifier (methyl bis phenyl vinyl silicon), stirring for 60min at 75 ℃, and stirring to obtain a modified resin solution;

distilling the modified resin solution under reduced pressure at 125 deg.C (i.e. at a temperature not lower than any boiling point of tetrahydrofuran and n-butanol) until the content of the residual organic solvent in the modified resin is 10%, and stopping distilling under reduced pressure to obtain modified resin;

(3) 5 parts of inorganic filler (Cd (CN))₂Mesh number of 800) was added to 100 parts of the modified resin, and then kneaded at 70 ℃ for 45min to obtain the ablation-resistant resin having a low expansion coefficient.

Comparative example 1

(1) Dissolving 50 parts of resin (boron phenolic resin) in 100 parts of organic solvent (a mixed solution of ethanol and dimethyl sulfoxide in a volume ratio of 1:1) to obtain a resin solution;

(2) distilling the resin solution under reduced pressure at 195 ℃ (i.e. not lower than the temperature of any boiling point of ethanol and dimethyl sulfoxide), and stopping distilling under reduced pressure until the content of the residual organic solvent in the modified resin is 8% to obtain the target resin;

(3) mixing 8 parts of inorganic filler (ZrW)₂O₈600 mesh) was added to 100 parts of the objective resin, and then kneaded at 70 ℃ for 60 minutes to obtain an ablation-resistant resin having a low coefficient of expansion.

Comparative example 2

Comparative example 2 is substantially the same as example 1 except that: the inorganic filler in the step (3) is CaCO₃。

The low expansion coefficient ablation resistant resins prepared in examples 1 to 5 and comparative examples 1 and 2 were subjected to a thermal expansion coefficient test and a char yield test at 800 c, respectively, to obtain data as shown in table 1. As can be seen from Table 1, the low expansion coefficient ablation resistant resins prepared in examples 1 to 5 all had a low coefficient of thermal expansion ((1-10). times.10)^－6/° c) and a relatively high carbon residue rate, and the coefficient of thermal expansion of the carbon fiber reinforced material is (1-3) × 10^－6The thermal expansion coefficients of the low-expansion-coefficient ablation-resistant resin and the carbon fiber reinforced material are similar, so that the thermal protection structure and the carbon fiber structure are in interface matching, the aircraft bearing structure obtained by adopting the composite design of the low-expansion-coefficient ablation-resistant resin and the carbon fiber reinforced material is more stable, and the stability of the aircraft can be improved. In comparative example 1, the resin was not modified, resulting in a significant decrease in the carbon residue rate; comparative example 2 although CaCO was added as an inorganic filler₃The coefficient of thermal expansion of the resin is reduced, but the char yield is still low due to the poor ablative properties of calcium carbonate itself.

TABLE 1

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.