Isocyanate-based polyimide foam material and preparation method thereof

Abstract

The present invention provides an isocyanate-based polyimide foam material and a preparation method thereof. The isocyanate-based polyimide foam material is prepared by including the following raw materials in parts by weight: 100-150 parts of unsaturated dianhydride, 120-200 parts of polyisocyanate, 80-150 parts of polar solvent, 5-15 parts of fatty alcohol, 10-20 parts of deionized water, 8-15 parts of foam stabilizer, 2-5 parts of first catalyst, 0.001-0.01 parts of second catalyst, 100-200 parts of hydrogen-containing polysiloxane; wherein the first catalyst is a chemical dehydration catalyst; and the second catalyst is a hydrosilylation catalyst. The isocyanate-based polyimide foam material obtained by the present invention has excellent flame retardant properties and mechanical properties, and is expected to be applied to high-end fields with special requirements for flame retardant properties.

Description

Technical Field

[0001] The invention relates to the technical field of polyimide material preparation, and in particular to an isocyanate-based polyimide foam material with improved flame retardancy and a preparation method thereof. Background Art

[0002] Isocyanate-Based Polyimide Foams (IBPIF) materials have attracted extensive attention from researchers in the fields of aerospace, ships, and construction due to their advantages such as simple preparation process and loose requirements for process equipment. However, the urea group generated by the reaction of isocyanate groups and amino groups during the foaming process of IBPIF materials makes IBPIF materials exhibit poor flame retardancy, thermal stability, and safety in use, resulting in IBPIF materials being used as thermal insulation, sound absorption, and noise reduction materials in cutting-edge technology fields such as aerospace and ships.

[0003] In view of the above problems, the current solution is to add flame retardants (such as expandable graphite, phosphorus flame retardants, graphene-loaded metal oxides, etc.) to prepare polyimide composite foam materials, but the disadvantage is that the addition of flame retardants often leads to a decrease in the mechanical strength of the obtained foam material, and the addition of graphene-loaded metal oxides also increases the density of the foam material. Therefore, isocyanate-based polyimide foam materials with excellent flame retardancy still need to be improved. Summary of the invention

[0004] The purpose of the present invention is to provide an isocyanate polyimide foam material with improved flame retardancy and a preparation method thereof in view of the deficiencies in the prior art, which can improve the flame retardancy without reducing other properties of the obtained foam material, such as mechanical properties.

[0005] In order to achieve the above object, the present invention adopts the following technical solution.

[0006] In a first aspect, the present invention provides an isocyanate-based polyimide foam material, which is prepared from raw materials including the following parts by weight:

[0007]

[0008]

[0009] Wherein, the first catalyst is a chemical dehydration catalyst; and the second catalyst is a hydrosilylation catalyst.

[0010] According to the isocyanate-based polyimide foam material provided by the present invention, unsaturated dianhydride is used to replace the traditional aromatic dianhydride, and hydrogen-containing polysiloxane is added. The hydrogen-containing polysiloxane can undergo a hydrosilylation reaction with the unsaturated group in the unsaturated dianhydride under the action of a second catalyst. The polysiloxane introduced into the foam material through a chemical reaction can play a flame retardant and reinforcing role at the same time, thereby improving the flame retardancy and mechanical strength of the foam material and giving the foam material excellent flexibility, without the need to add other flame retardants and reinforcing fillers.

[0011] In order to further improve the flame retardancy, the hydrogen-containing polysiloxane may introduce elements with flame retardant function such as fluorine, boron, and chlorine. According to the embodiment provided by the present invention, the structure of the hydrogen-containing polysiloxane is shown in formula (I):

[0012]

[0013] Wherein, 1≤m≤5, 2≤n≤10, and R is a fluoroalkyl group or a boryl group.

[0014] Preferably, 1≤m≤5, 2≤n≤8. If the molecular weight of the hydrogen-containing polysiloxane is too large, the uniformity of the foam will be affected.

[0015] Preferably, the chain length of the substituent R is not too long, and the number of carbon atoms does not exceed four.

[0016] According to an embodiment of the present invention, the fluoroalkyl group is -CH2CF3, -CH2CH2CF3 or -CH(CF3)2.

[0017] According to an embodiment provided by the present invention, the borane group is -CH2BH2, -CH2CH2BH2 or -CH2BCl2.

[0018] The unsaturated dianhydride is a dianhydride containing an unsaturated group, such as a dianhydride containing a double bond or a triple bond, preferably a phenylethynyl aromatic dianhydride. According to the embodiment provided by the present invention, the unsaturated dianhydride is one or both of 4,4'-(phenylethynyl terephthalate) diether dianhydride (PEQDA) and 4,4'-(phenylethynyl phenyl terephthalate) diether dianhydride (PEPHQDA), and the structure is shown below.

[0019]

[0020] The second catalyst is a hydrosilylation catalyst. According to an embodiment provided by the present invention, the second catalyst is one or more of Karstedt catalyst, chloroplatinic acid, chlororhodic acid and chloroiridic acid.

[0021] According to an embodiment provided by the present invention, the polyisocyanate is one or more of polyphenyl polymethylene polyisocyanate (PAPI), diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), isophorone diisocyanate (IPDI) and hexamethylene diisocyanate (HDI), but is not limited thereto.

[0022] According to an embodiment provided by the present invention, the polar solvent is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide.

[0023] According to an embodiment provided by the present invention, the fatty alcohol is at least one of methanol, ethanol, n-propanol, isopropanol, butanol, and isobutanol, preferably methanol or ethanol.

[0024] According to the embodiment provided by the present invention, the foam stabilizer is one or more of tetramethyl silicone oil, AK series silicone oil, DC series silicone oil and silicone, and its function is to improve the foaming stability, micropore size and micropore distribution uniformity.

[0025] The first catalyst is a chemical dehydration catalyst. According to an embodiment of the present invention, the first catalyst is one or more of isoquinoline, triethanolamine, triethylenediamine, stannous octoate, and dibutyltin dilaurate.

[0026] In a second aspect, the present invention provides a method for preparing the above-mentioned isocyanate-based polyimide foam material, comprising the following steps:

[0027] (1) dissolving an unsaturated dianhydride in a polar solvent at 80-100° C. with stirring, then adding a fatty alcohol and reacting under reflux at 60-80° C. to obtain a first solution;

[0028] (2) adding deionized water, a foam stabilizer and a first catalyst to the first solution, stirring and mixing at 50-80° C., adding hydrogen-containing polysiloxane, and continuing to stir and mix to obtain a second solution;

[0029] (3) adding polyisocyanate to the second solution, stirring evenly, then dropping a second catalyst and transferring the solution into a mold for free foaming to obtain a foam precursor;

[0030] (4) The foam precursor is first heated at 150-200°C for foaming, and then imidized at 250-300°C to obtain an isocyanate-based polyimide foam material.

[0031] The isocyanate-based polyimide foam material prepared by the invention has uniform pore size, excellent flame retardant performance, high mechanical strength and good toughness, and can meet the fire safety requirements of foam materials used in high-end fields such as aerospace.

[0032] Compared with the prior art, the present invention has the following technical effects:

[0033] The isocyanate-based polyimide foam material provided by the present invention uses unsaturated dianhydride to replace the traditional aromatic dianhydride, and adds hydrogen-containing polysiloxane. The hydrogen-containing polysiloxane can undergo a hydrosilylation reaction with the unsaturated group in the unsaturated dianhydride under the action of a second catalyst. The polysiloxane introduced into the foam material through a chemical reaction can simultaneously play a flame retardant and reinforcing role, thereby improving the flame retardancy and mechanical strength of the foam material and giving the foam material excellent flexibility. There is no need to add other flame retardants and reinforcing fillers, thereby broadening the application scope of isocyanate-based isocyanate-based polyimide foam materials. DETAILED DESCRIPTION

[0034] Unless otherwise specified, all scientific and technological terms used in the present invention have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. All patents and publications related to the present invention are incorporated herein by reference in their entirety. The term "comprising" or "including" is an open expression, that is, including the contents specified in the present invention, but does not exclude contents in other aspects.

[0035] According to a specific embodiment of the present invention, the preparation method of hydrogen-containing polysiloxane and isocyanate-based polyimide foam material is described in detail below.

[0036] 1. Preparation of hydrogen-containing polysiloxane

[0037] According to the embodiment provided by the present invention, the structure of the hydrogen-containing polysiloxane is shown in formula (I):

[0038]

[0039] Wherein, 1≤m≤5, 2≤n≤10, and R is a fluoroalkyl group or a boryl group.

[0040] When R is a fluoroalkyl group, taking R = -CH2CH2CF3 as an example, the preparation method of the corresponding compound (I-1) is as follows:

[0041] In a flask, the raw material (b) and the Karstedt catalyst are stirred and mixed, and then the flask is evacuated three times and filled with protective nitrogen gas. The raw material (a) trifluoropropylene is slowly introduced at 60°C and reacted for 30 minutes to obtain the reaction formula as follows:

[0042]

[0043] When R is a borane group, taking R = -CH2CH2BH2 as an example, the preparation method of the corresponding compound (I-2) is as follows:

[0044] In a flask, raw material (b) is stirred and mixed in a certain molar ratio under the action of Karstedt catalyst, and then vacuumed and exhausted three times, and then filled with protective gas nitrogen. Vinyl borane is slowly added dropwise at 80°C and reacted for 1 hour to obtain the reaction formula as follows:

[0045]

[0046] 2. Preparation of isocyanate-based polyimide foam materials

[0047] According to an embodiment provided by the present invention, the method for preparing the isocyanate-based polyimide foam material with improved flame retardancy comprises:

[0048] 1) dissolving an unsaturated dianhydride in a polar solvent at 80-100° C. with stirring, and then adding a fatty alcohol to react under reflux at 60-80° C. to obtain a first solution;

[0049] (2) adding deionized water, a foam stabilizer and a first catalyst to the first solution, stirring and mixing at 50-80° C., adding hydrogen-containing polysiloxane, and continuing to stir and mix to obtain a second solution;

[0050] (3) adding polyisocyanate to the second solution, stirring evenly, then dropping a second catalyst and transferring the solution into a mold for free foaming to obtain a foam precursor;

[0051] (4) The foam precursor is heated at 150-200° C. for foaming, and then imidized at 250-300° C. to obtain a polyimide foam material with improved flame retardancy.

[0052] According to the embodiment provided by the present invention, the unsaturated dianhydride is one or both of 4,4'-(phenylethynyl terephthalate) dianhydride (PEQDA) and 4,4'-(phenylethynyl phenyl terephthalate) dianhydride (PEPHQDA), and the amount used is 100-150 parts by weight.

[0053] According to the embodiment provided by the present invention, the structure of the hydrogen-containing polysiloxane is shown in formula (I):

[0054]

[0055] Wherein, 1≤m≤5, 2≤n≤10, and R is a fluoroalkyl group or a boryl group.

[0056] Preferably, 1≤m≤5, 2≤n≤8. If the molecular weight of the hydrogen-containing polysiloxane is too large, the uniformity of the foam will be affected.

[0057] In some embodiments, the fluoroalkyl group is -CH2CF3, -CH2CH2CF3, or -CH(CF3)2.

[0058] In some embodiments, the borane group is -CH2BH2, -CH2CH2BH2, or -CH2BCl2.

[0059] The second catalyst is a hydrosilylation catalyst. According to an embodiment provided by the present invention, the second catalyst is one or more of a Karstedt catalyst, chloroplatinic acid, chlororhodic acid and chloroiridic acid. Under the action of the catalyst, the silicon-hydrogen bond in the hydrogen-containing siloxane can undergo a hydrosilylation reaction with the alkynyl group in the unsaturated dianhydride, thereby introducing the polysiloxane into the foam material.

[0060] The amount of the hydrogen-containing polysiloxane used is 100-200 parts by weight. In some embodiments, the amount of the hydrogen-containing polysiloxane used is 100 parts by weight.

[0061] The second catalyst is used in an amount of 0.001-0.01 parts by weight. In some embodiments, the second catalyst is used in an amount of 0.005-0.01 parts by weight.

[0062] According to an embodiment provided by the present invention, the polyisocyanate is one or more of polyphenyl polymethylene polyisocyanate (PAPI), diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), isophorone diisocyanate (IPDI) and hexamethylene diisocyanate (HDI).

[0063] The polyisocyanate is used in an amount of 120-200 parts by weight. In some embodiments, the polyisocyanate is used in an amount of 150-200 parts by weight.

[0064] According to an embodiment provided by the present invention, the polar solvent is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide.

[0065] The polar solvent is used in an amount of 80-150 parts by weight. In some embodiments, the polar solvent is used in an amount of 100-150 parts by weight.

[0066] According to an embodiment provided by the present invention, the fatty alcohol is at least one of methanol, ethanol, n-propanol, isopropanol, butanol, and isobutanol, preferably methanol or ethanol.

[0067] The fatty alcohol is used in an amount of 5-15 parts by weight. In some embodiments, the fatty alcohol is used in an amount of 10-15 parts by weight.

[0068] The deionized water is used in an amount of 10-20 parts by weight. In some embodiments, the deionized water is used in an amount of 15 parts by weight.

[0069] According to the embodiment provided by the present invention, the foam stabilizer is one or more of tetramethyl silicone oil, AK series silicone oil, DC series silicone oil and silicone.

[0070] The foam stabilizer is used in an amount of 8-15 parts by weight. In some embodiments, the foam stabilizer is used in an amount of 10 parts by weight.

[0071] The first catalyst is a chemical dehydration catalyst. According to an embodiment of the present invention, the first catalyst is one or more of isoquinoline, triethanolamine, triethylenediamine, stannous octoate, and dibutyltin dilaurate.

[0072] The first catalyst is used in an amount of 2-5 parts by weight. In some embodiments, the first catalyst is used in an amount of 5 parts by weight.

[0073] In some embodiments, the method for preparing the isocyanate-based polyimide foam material specifically comprises:

[0074] (1) dissolving an unsaturated dianhydride in a polar solvent at 80-100° C. with stirring, then adding a fatty alcohol and reacting under reflux at 60-80° C. for 0.5-1 h to obtain a first solution;

[0075] (2) adding deionized water, a foam stabilizer and a first catalyst to the first solution, stirring and mixing at 50-80° C., adding hydrogen-containing polysiloxane, and continuing to stir and mix to obtain a second solution;

[0076] (3) adding polyisocyanate to the second solution, stirring evenly, then dropping a second catalyst and transferring the solution into a mold for free foaming to obtain a foam precursor;

[0077] (4) The foam precursor is first heated at 150-200° C. for foaming for 1-2 hours, and then imidized at 250-300° C. for 1-2.5 hours to obtain an isocyanate-based polyimide foam material.

[0078] The embodiments of the present invention will be described in detail below in conjunction with the examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. In the examples, if no specific conditions are specified, the conditions described in the specification or the conventional conditions or the conditions recommended by the manufacturer are followed. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0079] In the specific embodiment of the present invention, the dosage of each component is parts by weight.

[0080] Example 1

[0081] In this embodiment, a method for preparing an isocyanate-based polyimide foam material is provided, comprising:

[0082] (1) adding 100 parts of PEQDA to 100 parts of DMF, stirring and dissolving at 80° C., then adding 15 parts of methanol and refluxing at 65° C. for 1 h to obtain a first solution;

[0083] (2) adding 10 parts of deionized water, 10 parts of tetramethyl silicone oil and 5 parts of triethanolamine to the first solution, stirring and mixing at 60° C., adding 100 parts of hydrogen-containing polysiloxane (I-1), continuing to stir and mix evenly, to obtain a second solution;

[0084] (3) quickly adding 200 parts of PAPI to the second solution, stirring and mixing, dropping 0.005 parts of Karstedt catalyst, and then transferring into a mold for free foaming to obtain a foam precursor;

[0085] (4) The foam precursor is first heated at 180° C. for foaming for 2 h, and then imidized at 300° C. for 1 h to obtain a polyimide foam material with improved flame retardancy.

[0086] Example 2

[0087] In this embodiment, a method for preparing an isocyanate-based polyimide foam material is provided, comprising:

[0088] (1) adding 100 parts of PEPHQDA to 100 parts of DMF, stirring and dissolving at 80° C., then adding 15 parts of methanol and refluxing at 65° C. for 1 h to obtain a first solution;

[0089] (2) adding 10 parts of deionized water, 10 parts of tetramethyl silicone oil and 5 parts of triethanolamine to the first solution, stirring and mixing at 60° C., adding 100 parts of hydrogen-containing polysiloxane (I-1), continuing to stir and mix evenly, to obtain a second solution;

[0090] (3) quickly adding 200 parts of PAPI to the second solution, stirring and mixing, dropping 0.005 parts of Karstedt catalyst, and then transferring into a mold for free foaming to obtain a foam precursor;

[0091] (4) The foam precursor is first heated at 180° C. for foaming for 2 h, and then imidized at 300° C. for 1 h to obtain a polyimide foam material with improved flame retardancy.

[0092] Example 3

[0093] In this embodiment, a method for preparing an isocyanate-based polyimide foam material is provided, comprising:

[0094] (1) adding 100 parts of PEQDA to 100 parts of DMF, stirring and dissolving at 80° C., then adding 15 parts of methanol and refluxing at 65° C. for 1 h to obtain a first solution;

[0095] (2) adding 10 parts of deionized water, 10 parts of tetramethyl silicone oil and 5 parts of triethanolamine to the first solution, stirring and mixing at 60° C., adding 100 parts of hydrogen-containing polysiloxane (I-2), continuing to stir and mix evenly, to obtain a second solution;

[0096] (3) quickly adding 200 parts of PAPI to the second solution, stirring and mixing, dropping 0.005 parts of Karstedt catalyst, and then transferring into a mold for free foaming to obtain a foam precursor;

[0097] (4) The foam precursor is first heated at 180° C. for foaming for 2 h, and then imidized at 300° C. for 1 h to obtain a polyimide foam material with improved flame retardancy.

[0098] Example 4

[0099] In this embodiment, a method for preparing an isocyanate-based polyimide foam material is provided, comprising:

[0100] (1) adding 100 parts of PEPHQDA to 100 parts of DMF, stirring and dissolving at 80° C., then adding 15 parts of methanol and refluxing at 65° C. for 1 h to obtain a first solution;

[0101] (2) adding 10 parts of deionized water, 10 parts of tetramethyl silicone oil and 5 parts of triethanolamine to the first solution, stirring and mixing at 60° C., adding 100 parts of hydrogen-containing polysiloxane (I-2), continuing to stir and mix evenly, to obtain a second solution;

[0102] (3) quickly adding 200 parts of PAPI to the second solution, stirring and mixing, dropping 0.005 parts of Karstedt catalyst, and then transferring into a mold for free foaming to obtain a foam precursor;

[0103] (4) The foam precursor is first heated at 180° C. for foaming for 2 h, and then imidized at 300° C. for 1 h to obtain a polyimide foam material with improved flame retardancy.

[0104] Comparative Example 1

[0105] (1) 100 parts of PEQDA were dissolved in 100 parts of DMF at 80° C. with stirring, and then 15 parts of methanol were added and refluxed at 65° C. for 1 h to obtain a first solution;

[0106] (2) adding 10 parts of deionized water, 10 parts of tetramethyl silicone oil as a foam stabilizer and 5 parts of triethanolamine as a catalyst to the above solution, stirring and dispersing at 60° C., then adding 5 parts of graphite as a flame retardant, and continuing to stir and mix evenly to obtain a suspension;

[0107] (3) quickly adding 200 parts of PAPI to the above suspension, stirring to obtain a mixed slurry, and pouring the mixed slurry into a mold for free foaming to obtain a foam precursor;

[0108] (4) The foam precursor is heated at 180° C. for foaming for 2 h, and then imidized at 300° C. for 1 h to obtain an isocyanate-based polyimide foam material.

[0109] Comparative Example 2

[0110] (1) 100 parts of PEQDA were dissolved in 100 parts of DMF at 80° C. with stirring, and then 15 parts of methanol were added and refluxed at 65° C. for 1 h to obtain a first solution;

[0111] (2) adding 10 parts of deionized water, 10 parts of tetramethyl silicone oil as a foam stabilizer and 5 parts of triethanolamine as a catalyst to the above solution, stirring and dispersing at 60° C., then adding 5 parts of red phosphorus as a flame retardant, and continuing to stir and mix evenly to obtain a suspension;

[0112] (3) quickly adding 200 parts of PAPI to the above suspension, stirring to obtain a mixed slurry, and pouring the mixed slurry into a mold for free foaming to obtain a foam precursor;

[0113] (4) The foam precursor is heated at 180° C. for foaming for 2 h, and then imidized at 300° C. for 1 h to obtain an isocyanate-based polyimide foam material.

[0114] Performance Testing

[0115] The density, compression strength, heat release rate, limiting oxygen index and vertical combustion of the foam material prepared above were tested according to the standards of compression GB / T 8813-2008, microcalorimeter ASTM D7309, limiting oxygen index GB / T2406-93, and vertical combustion UL94. The test results are shown in Table 1.

[0116] Table 1

[0117]

[0118] It can be seen from the data in Table 1 that the isocyanate polyimide foam material obtained in the embodiment of the present invention has a heat release rate of less than 30 J / g·K, a limiting oxygen index greater than 37%, and a compressive strength of more than 3 MPa, which is significantly better than the foam material obtained by adding general flame retardants such as graphite and red phosphorus.

[0119] In the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", "embodiment", "example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0120] Although the embodiments and examples of the present invention have been shown and described above, it is to be understood that the above embodiments and examples are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments and examples within the scope of the present invention.

Claims

1. An isocyanate-based polyimide foam material, characterized in that: It is prepared from the following raw materials in parts by weight: Wherein, the structure of the hydrogen-containing polysiloxane is shown in formula (I): Wherein, 1≤m≤5, 2≤n≤10, R is a fluoroalkyl group or a borane group; The fluoroalkyl group is -CH2CF3, -CH2CH2CF3 or -CH(CF3)2; the boryl group is -CH2BH2, -CH2CH2BH2 or -CH2BCl2; The unsaturated dianhydride is one or both of 4,4'-(phenylethynyl terephthalide) dianhydride and 4,4'-(phenylethynyl phenylterephthalide) dianhydride; The first catalyst is a chemical dehydration catalyst; the second catalyst is a hydrosilylation catalyst.

2. The isocyanate-based polyimide foam material according to claim 1, characterized in that: The polyisocyanate is one or more of polyphenyl polymethylene polyisocyanate, diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate and hexamethylene diisocyanate.

3. The isocyanate-based polyimide foam material according to claim 1, characterized in that: The polar solvent is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide; the fatty alcohol is one or more of methanol, ethanol, n-propanol, isopropanol, butanol, and isobutanol.

4. The isocyanate-based polyimide foam material according to claim 1, characterized in that: The foam stabilizer is one or more of tetramethyl silicone oil, AK series silicone oil, DC series silicone oil and silicone.

5. The isocyanate-based polyimide foam material according to claim 1, characterized in that: The first catalyst is one or more of isoquinoline, triethanolamine, triethylenediamine, stannous octoate and dibutyltin dilaurate; the second catalyst is one or more of Karstedt catalyst, chloroplatinic acid, chlororhodic acid and chloroiridic acid.

6. The method for preparing the isocyanate-based polyimide foam material according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) dissolving an unsaturated dianhydride in a polar solvent at 80-100° C. with stirring, then adding a fatty alcohol and reacting under reflux at 60-80° C. to obtain a first solution; (2) adding deionized water, a foam stabilizer and a first catalyst to the first solution, stirring and mixing at 50-80° C., adding hydrogen-containing polysiloxane, and continuing to stir and mix to obtain a second solution; (3) adding polyisocyanate to the second solution, stirring evenly, then dropping a second catalyst and transferring the solution into a mold for free foaming to obtain a foam precursor; (4) The foam precursor is first heated at 150-200°C for foaming, and then imidized at 250-300°C to obtain an isocyanate-based polyimide foam material.

7. Application of the isocyanate polyimide foam material according to any one of claims 1 to 5 in the field of aerospace.

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