Polyimide gel composition, polyimide aerogel, preparation method of polyimide aerogel, thermal insulation coating, functional element and electronic equipment

Abstract

The invention provides a polyimide gel composition, polyimide aerogel and a preparation method thereof, a thermal insulation coating, a functional element and electronic equipment. The imide gel composition comprises polyamide acid sol, a first additive and a second additive, the first additive comprises a proton acceptor compound, and the second additive comprises an amino acid compound. The polyimide gel composition provided by the invention can be used for preparing polyimide aerogel, and the obtained polyimide aerogel has low thermal conductivity and low dielectric constant at the same time, and is suitable for providing insulating parts with lower thermal conductivity for various electronic devices.

Description

Technical Field

[0001] The present invention relates to the field of aerogels, and in particular to a polyimide gel composition, a polyimide aerogel and a preparation method thereof, a thermal insulation coating, a functional element, and an electronic device. Background Art

[0002] Insulating materials, also known as dielectrics, are substances that conduct electricity only slightly or not at the permissible voltage. Their primary function in electronic devices is to separate charged conductors of different potentials, allowing current to flow along a defined path to ensure safe operation. Insulating materials also provide mechanical support and fixation to protect conductors.

[0003] Aerogel, a material with a porous three-dimensional network structure, is widely used as an insulation component in aerospace, sensors, batteries, and energy storage devices due to its high specific surface area, high porosity, low density, and low dielectric constant. However, as consumer electronics become smaller and more high-frequency, their power consumption and heat generation are increasing. Therefore, the corresponding insulation components require not only a low dielectric constant and low density, but also lower thermal conductivity. However, the insulation capacity and thermal conductivity of existing aerogel materials cannot meet the requirements of miniaturized consumer electronics. Summary of the Invention

[0004] The present invention provides a polyimide gel composition, which can be used to prepare polyimide aerogel. The obtained polyimide aerogel has both low thermal conductivity and low dielectric constant, and is suitable for providing insulating parts with lower thermal conductivity for various electronic devices.

[0005] The present invention also provides a polyimide aerogel prepared from the polyimide gel composition. The polyimide aerogel has both low thermal conductivity and low dielectric constant, and is suitable for providing insulating parts with lower thermal conductivity for various electronic devices.

[0006] The present invention also provides a method for preparing the polyimide aerogel. The polyimide aerogel can be obtained by subjecting the polyimide gel composition to heat treatment, and the operation is simple.

[0007] The present invention also provides a thermal insulation coating, which can be used to prepare a thermal insulation layer with excellent thermal insulation effect.

[0008] The present invention also provides a functional element. Since the insulation element includes the polyimide aerogel, it can provide insulation conditions for electronic equipment and prevent thermal runaway caused by overheating.

[0009] The present invention also provides an electronic device, which has good performance and safety due to the above-mentioned functional elements.

[0010] In a first aspect, the present invention provides a polyimide gel composition, comprising: a polyamic acid sol, a first additive, and a second additive, wherein the first additive comprises a proton acceptor compound, and the second additive comprises an amino acid compound.

[0011] Optionally, the proton acceptor compound comprises a nitrogen-containing compound and / or a phosphine-based compound.

[0012] Optionally, the nitrogen-containing compound includes an amino compound and / or a nitrogen heterocyclic compound.

[0013] Optionally, the amino compound includes at least one of methylamine, urea, ethylamine, ethanolamine, ethylenediamine, dimethylamine, trimethylamine, triethylamine, propylamine, isopropylamine, 1,3-propylenediamine, 1,2-propylenediamine, tripropylamine, triethanolamine, butylamine, isobutylamine, tert-butylamine, hexylamine, octylamine, aniline, benzylamine, cyclohexylamine, hexamethylenetetramine, o-toluidine, m-toluidine, p-toluidine, diphenylamine, and benzidine;

[0014] And / or, the nitrogen heterocyclic compound includes at least one of quinoline, isoquinoline, pyridine, and 3-methylpyridine.

[0015] Optionally, the phosphine-based compound includes at least one of trimethylphosphine, triethylphosphine, and tripropylphosphine.

[0016] Optionally, the amino acid compounds include: glycine, alanine, valine, leucine, isoleucine, methionine (methionine), proline, tryptophan, serine, tyrosine, cysteine, phenylalanine, asparagine, glutamine, threonine, aspartic acid, glutamic acid, lysine, arginine and histidine, β-alanine, γ-aminobutyric acid, L-homoarginine, L-citrulline, L-ornithine, L-hydroxyproline, L-alloleucine, L-norvaline, L-selenocysteine, At least one of L-pyrrolysine, D-alanine, D-glutamic acid, D-serine, L-theanine, L-anserine, L-carnosine, L-kynurenine, L-3-methylhistidine, L-homocysteine, L-homoserine, L-p-hydroxyphenylglycine, L-m-hydroxyphenylglycine, L-o-hydroxyphenylglycine, L-phenylglycine, L-cyclopropylglycine, L-cyclobutylglycine, L-cyclopentylglycine, L-cyclohexylglycine, L-2-aminobutyric acid, and L-3-aminobutyric acid.

[0017] Optionally, the polyamic acid sol is obtained by polymerizing a raw material system including dianhydride monomers and diamine monomers.

[0018] Optionally, the first additive is 5%-60% of the molar amount of the dianhydride monomer; and / or the second additive is 0.005%-0.10% of the molar amount of the dianhydride monomer.

[0019] Optionally, the first additive is 10%-30% of the molar amount of the dianhydride monomer; and / or the second additive is 0.01%-0.05% of the molar amount of the dianhydride monomer.

[0020] Optionally, the composition further includes a solvent, which includes one or more of N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, N-ethylpyrrolidone, N-propylpyrrolidone, N-butylpyrrolidone, N-cyclohexylpyrrolidone, N-benzylpyrrolidone, N,N-diethylformamide, 1,3-dimethyl-2-imidazolidinone, tetrahydrofuran, dimethyl sulfoxide, p-chlorophenol, 1,3-dimethyl-2-imidazolidinone, diphenyl sulfone, 4,4'-dimethyldiphenyl sulfone, 4,4'-dichlorodiphenyl sulfone, methyl phenyl sulfoxide, diethyl sulfone, dipropyl sulfone, dibutyl sulfone, trifluoromethylphenyl sulfoxide, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl acetate, ethyl acetate, γ-butyrolactone, hexafluoroisopropanol, methyl benzoate, and ethyl benzoate.

[0021] In a second aspect, the present invention provides a polyimide aerogel prepared from the polyimide gel composition described in the first aspect.

[0022] Optionally, the thermal conductivity of the polyimide aerogel is not higher than 0.022 W / (m·K), and the dielectric constant is not greater than 1.20.

[0023] Optionally, the density of the polyimide aerogel is not higher than 0.12 g / cm 3 ;

[0024] And / or, the porosity of the polyimide aerogel is 90%-95%;

[0025] And / or, the pore size of the polyimide aerogel is 10 μm-40 μm.

[0026] Optionally, the polyimide aerogel is prepared by heat-treating the polyimide gel composition described in the first aspect.

[0027] In a third aspect, the present invention provides a method for preparing a polyimide aerogel, comprising the following steps:

[0028] The polyimide gel composition described in the first aspect is subjected to heat treatment to obtain the polyimide aerogel.

[0029] Optionally, the heat treatment pressure is 0.9-0.12 MPa;

[0030] And / or, the heat treatment further includes: heating to 80°C-180°C at a heating rate of 10°C / min-30°C / min, keeping the temperature for 10min-50min, continuing to heat to 300°C-400°C, and keeping the temperature for a second time for 10min-50min.

[0031] The thickness of the polyimide gel composition is measured as L0. After the heat treatment, the thickness of the polyimide aerogel is measured as L1. L0 and L1 satisfy the following formula 1:

[0032]

[0033] In a fourth aspect, the present invention provides a thermal insulation coating comprising the polyimide gel composition described in the first aspect, or the polyimide aerogel described in the second aspect, or the polyimide aerogel prepared in the third aspect.

[0034] In the fourth and fifth aspects, the present invention provides a functional element prepared from the polyimide gel composition described in the first aspect, or prepared from the thermal insulation coating described in the fourth aspect, or including the polyimide aerogel described in the second aspect.

[0035] Optionally, the functional element is at least one of a heat insulation layer, an insulating layer, and an insulating shell.

[0036] In a sixth aspect, the present invention provides an electronic device comprising the functional element described in the fifth aspect.

[0037] The polyimide gel composition provided by the present invention can be used to prepare polyimide aerogel, and the obtained polyimide aerogel has both low thermal conductivity and low dielectric constant, and is suitable for providing insulating parts with lower thermal conductivity for various electronic devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0039] Figure 1 This is a SEM image of the longitudinal section (in the plane direction) of the polyimide aerogel prepared in Example 1 of the present invention.

[0040] Figure 2 This is a SEM image of the cross section (thickness direction) of the polyimide aerogel prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below. The specific embodiments listed below are only for describing the principles and features of the present invention. The examples are only used to explain the present invention and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts are within the scope of protection of the present invention.

[0042] Aerogel materials currently on the market include graphene aerogel, cellulose aerogel, metal aerogel, carbon aerogel, etc. Although these aerogels are also widely used in the field of insulation and thermal insulation, they usually lack the balance between thermal conductivity and dielectric constant, making it difficult to meet the needs of miniaturized consumer electronic products.

[0043] As a polymer material with unique physical and chemical properties, polyimide has shown great application potential in many fields. It has excellent thermal stability, chemical stability, mechanical properties, and good dielectric properties. When it exists in the form of a porous structure such as aerogel, it is expected to obtain a series of excellent properties such as light weight, thermal insulation, and adsorption brought by low density and high porosity. Therefore, the present invention provides the following technical solutions:

[0044] In one aspect, the present invention provides a polyimide gel composition, comprising: a polyamic acid sol, a first additive, and a second additive, wherein the first additive comprises a proton acceptor compound, and the second additive comprises an amino acid compound.

[0045] The above-mentioned polyimide gel composition can be used to prepare polyimide aerogels with low thermal conductivity and low dielectric constant by introducing a first additive and a second additive. Specifically, by adding a first additive having a proton acceptor and an amino acid-based second additive to the polyamic acid sol, the introduction of the two additives causes cyclic hydrogen bonds to form between the polyamic acid molecules and the solvent molecules, thereby reducing the surface tension of the solvent and the force of the solvent on the pore structure of the polyimide during the subsequent volatilization process. In addition, the cyclic hydrogen bonds are broken in the subsequent process, and the additives then become gas and leave, causing the film to expand, thereby obtaining a polyimide aerogel with good porosity and low density.

[0046] In one embodiment, the proton acceptor compound comprises a nitrogen-containing compound and / or a phosphine-based compound.

[0047] Among them, nitrogen-containing compounds are suitable for neutral / weakly acidic systems due to their high proton affinity, low cost and easy synthesis, while phosphine-based compounds are more suitable for extreme environments due to their strong Lewis basicity and high temperature / oxidation stability. The two adapt to the needs of different scenarios through differences in electronic structure.

[0048] In one embodiment, the nitrogen-containing compound includes an amino compound and / or a nitrogen heterocyclic compound.

[0049] Among them, amino compounds and nitrogen heterocyclic compounds have higher proton affinity, and are therefore more conducive to the formation of stable cyclic hydrogen bonds, thereby realizing the normal pressure preparation of polyimide aerogels.

[0050] In a specific embodiment, the amino compound includes: at least one of methylamine, urea, ethylamine, ethanolamine, ethylenediamine, dimethylamine, trimethylamine, triethylamine, propylamine, isopropylamine, 1,3-propylenediamine, 1,2-propylenediamine, tripropylamine, triethanolamine, butylamine, isobutylamine, tert-butylamine, hexylamine, octylamine, aniline, benzylamine, cyclohexylamine, hexamethylenetetramine, o-toluidine, m-toluidine, p-toluidine, diphenylamine, and benzidine.

[0051] Among them, the above amino compounds can accept protons and have the characteristics of good solubility and suitable volatilization temperature. Therefore, they can be evenly dispersed in the mixed material to better induce the formation of cyclic hydrogen bonds between polyamino acid molecules and solvent molecules, and fully exert their properties during the heat treatment process, thereby ensuring the successful preparation of polyimide aerogel.

[0052] In a specific embodiment, the nitrogen heterocyclic compound includes at least one of quinoline, isoquinoline, pyridine, and 3-methylpyridine.

[0053] Among them, the above nitrogen heterocyclic compounds can accept protons and also have good solubility and volatility. Therefore, they can be evenly dispersed in the mixed material, better inducing the formation of cyclic hydrogen bonds between polyamino acid molecules and solvent molecules, and fully exerting their effects during the heat treatment process, thereby ensuring the successful preparation of polyimide aerogel.

[0054] In a specific embodiment, the phosphine-based compound includes at least one of trimethylphosphine, triethylphosphine, and tripropylphosphine.

[0055] Among them, the above phosphine-based compounds can be evenly dispersed in the solvent, and can better induce the formation of cyclic hydrogen bonds between polyamino acid molecules and solvent molecules, thereby helping to form polyimide aerogels with low dielectric constant and low thermal conductivity.

[0056] In a specific embodiment, the amino acid compounds include: glycine, alanine, valine, leucine, isoleucine, methionine (methionine), proline, tryptophan, serine, tyrosine, cysteine, phenylalanine, asparagine, glutamine, threonine, aspartic acid, glutamic acid, lysine, arginine and histidine, β-alanine, γ-aminobutyric acid, L-homoarginine, L-citrulline, L-ornithine, L-hydroxyproline, L-alloisoleucine, L-norvaline, L-selenocysteine at least one of amino acid, L-pyrrolysine, D-alanine, D-glutamic acid, D-serine, L-theanine, L-anserine, L-carnosine, L-kynurenine, L-3-methylhistidine, L-homocysteine, L-homoserine, L-p-hydroxyphenylglycine, L-m-hydroxyphenylglycine, L-o-hydroxyphenylglycine, L-phenylglycine, L-cyclopropylglycine, L-cyclobutylglycine, L-cyclopentylglycine, L-cyclohexylglycine, L-2-aminobutyric acid, and L-3-aminobutyric acid.

[0057] Among them, the above amino acid compounds regulate proton balance by relying on the synergistic effect of the dual functional groups of amino group (-NH2) and carboxylic acid group (-COOH), and have the advantages of dual functional group synergy, structural modifiability and low cost, which are adapted to the high performance and environmental protection requirements in the fields of functional components, electronic equipment and polymer materials.

[0058] In a specific embodiment, the polyamic acid sol is obtained by polymerizing a raw material system including dianhydride monomers and diamine monomers.

[0059] For example, the diamine monomers include, but are not limited to, p-phenylenediamine, 4,4'-diaminobiphenyl, 2,2-bis(4-aminophenyl)hexafluoropropane (6FpDA), 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (6FAP), bis(3-amino-4-hydroxyphenyl)sulfone (BAHS), 2,2'-hydroxy-3,3'-diaminobiphenyl, 3,3'-dihydroxybenzidine, 2,2'-dimethyl-3,3'-dihydroxybenzidine, 2-amino-4-[(3-amino- 4-hydroxyphenyl)methyl]phenol, 2,2-bis(4-hydroxy-3-aminophenyl)propane (BAP), 4,4'-methylenebis[2-amino-6-methyl]phenol, bis(3-amino-4-hydroxyphenyl)methanone, (3-amino-4-hydroxyphenyl)(4-aminophenyl)methanone, (3-amino-4-hydroxyphenyl)(3-aminophenyl)methanone, 4-methyl-4'-diaminobiphenyl, 4-methoxy-4'-diaminobiphenyl, 4,4'-diaminodiphenylmethane, 2,2'-methylene bis(6-amino-4-fluoro)phenol, 4,6-diaminoresorcinol, 1,3,5-trihydroxy-2,4,6-triaminobenzene, 2,4-diamino-1,3-benzenediol, 2,4,6-triamino-1,3-benzenediol, 3,5-diamino-1,2,4-benzenetriol, 4,6-diamino-1,2,3-benzenetriol, 4,6-diamino-2-methyl-1,3-benzenediol, 2-(2,4-diaminophenoxy)-1,4-benzenediol, 4,6-diamino-2-chloro-1,3 -benzenediol, 2,4-diamino-5-fluorophenol, 4,6-diamino-2,5-difluoro-1,3-benzenediol, 2,6-diaminotrifluorotoluene, 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl ether, 2,2'-bis(trifluoromethyl)diaminobiphenyl, 4,4'-diaminodiphenyl ether (ODA), 4-methyl-4'-diaminodiphenyl ether, 3-methoxy-3'-diaminodiphenyl ether, 1,4-bis(2-trifluoromethyl-4-aminophenoxy)benzene, at least one or more thereof.

[0060] For example, the dianhydride monomers include, but are not limited to, pyromellitic dianhydride (PMDA), 5,5'-oxybis-(cis-5-norbornane-exo-2,3'-dicarboxylic anhydride), exo-2,2',3,3'-bi(cis-5-norbornane) dicarboxylic anhydride, 5,5'-hexafluoroisopropylidenebis-(cis-5-norbornane-exo-2,3'-dicarboxylic anhydride), hexafluorodianhydride (6FDA), 2,2'-difluoromethyl-4,4',5,5'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), cyclobutanetetracarboxylic dianhydride (CBDA) 、3,6-bis(trifluoromethyl)-1,2,4,5-tetracarboxylic dianhydride, 6-trifluoromethyl-1,2,4,5-benzenetetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride (ODPA), 4,4'-oxydi-o-(2-trifluoromethylphenyl)phthalic anhydride, 3,3',4,4'-tetracarboxylic-2,2'-bis(trifluoromethyl)diphenyl ether diamine, 1,2,4,5-cyclohexanetetracarboxylic dianhydride (HPMDA), dicyclohexyl-3,4,3',4'-tetracarboxylic dianhydride (HBPDA), bisphenol A diether dianhydride (BPADA), bisphenol F diether dianhydride (BPFDA), Pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 4,4'-biphenyl ether dianhydride, 3,4,3',4'-triphenyl diether dianhydride, biphenyl diether dianhydride, 4,4'-(hexafluoroisopropylene) diphthalic anhydride, 2,2-diphenylpropane-3,4,3',4'-tetracarboxylic dianhydride, p-phenylene-diphenyl trimellitic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfone tetracarboxylic dianhydride, bisphenol S diester dianhydride, dicyclohexyl-3,4,3',4'-tetracarboxylic dianhydride, 1-bromo Perylene-3,4,9,10-tetracarboxylic dianhydride, 9,9-bis(trifluoromethyl)-2,3,6,7-xanthene tetracarboxylic dianhydride (6FCDA), p-biphenylene-diphenyl trimellitic dianhydride, tetrachloroperylene anhydride, bisphenol AF diester dianhydride, 1,6,7,12-tetra-tert-butylphenoxy-3,4,9,10-tetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, diphenyl sulfide dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 2-bromonaphthalene-1,4,5,8-tetracarboxylic 1,8:4,5-dianhydride, 2,3,3',4'-diphenylsulfonetetracarboxylic dianhydride, bicyclo[2.2.2] At least one or more of oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, diethylenetriaminepentaacetic dianhydride, 2,2'-difluoromethyl-4,4',5,5'-biphenyltetracarboxylic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride, 3,3,4,4-diphenylsulfonetetracarboxylic dianhydride, p-phenylene-diphenyltrimethylol dianhydride, 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride, and 1,2,4,5-cyclohexanetetracarboxylic dianhydride.

[0061] In one embodiment, the first additive is 5% to 60% of the molar weight of the dianhydride monomer.

[0062] In a specific embodiment, the second additive is 0.005%-0.10% of the molar weight of the dianhydride monomer.

[0063] The first additive and the second additive added in the above-mentioned amount range can further ensure the dispersibility of the two additives in the solvent, while ensuring the high porosity, low density and low shrinkage of the polyimide aerogel, thereby ensuring the low dielectric and low thermal conductivity of the polyimide aerogel.

[0064] For example, the first additive is any value selected from the group consisting of 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, or any range consisting of both, of the molar amount of the dianhydride monomer. The second additive is any value selected from the group consisting of 0.005%, 0.006%, 0.007%, 0.008%, 0.009%, 0.10%, or any range consisting of both, of the molar amount of the dianhydride monomer.

[0065] In order to further ensure the high porosity, low density and low shrinkage characteristics of the polyimide aerogel, thereby ensuring the low dielectric and low thermal conductivity of the polyimide aerogel, in one specific embodiment, the first additive is 10%-30% of the molar amount of the dianhydride monomer.

[0066] In order to further ensure the high porosity, low density and low shrinkage characteristics of the polyimide aerogel, thereby ensuring the low dielectric and low thermal conductivity of the polyimide aerogel, in one embodiment, the second additive is 0.01%-0.05% of the molar weight of the dianhydride monomer.

[0067] In a specific embodiment, the composition further includes a solvent, and the solvent includes one or more of N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, N-ethylpyrrolidone, N-propylpyrrolidone, N-butylpyrrolidone, N-cyclohexylpyrrolidone, N-benzylpyrrolidone, N,N-diethylformamide, 1,3-dimethyl-2-imidazolidinone, tetrahydrofuran, dimethyl sulfoxide, p-chlorophenol, 1,3-dimethyl-2-imidazolidinone, diphenyl sulfone, 4,4'-dimethyldiphenyl sulfone, 4,4'-dichlorodiphenyl sulfone, methyl phenyl sulfoxide, diethyl sulfone, dipropyl sulfone, dibutyl sulfone, trifluoromethylphenyl sulfoxide, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl acetate, ethyl acetate, γ-butyrolactone, hexafluoroisopropanol, methyl benzoate, and ethyl benzoate.

[0068] In a second aspect, the present invention provides a polyimide aerogel prepared from the polyimide gel composition described in the first aspect.

[0069] First, since the polyimide aerogel is prepared from the polyimide gel composition, the polyimide aerogel has both low thermal conductivity and low dielectric constant, and is suitable for providing insulating components with lower thermal conductivity for various electronic devices.

[0070] In one specific embodiment, the thermal conductivity of the polyimide aerogel is not higher than 0.022 W / (m·K), and the dielectric constant is not greater than 1.20.

[0071] The polyimide aerogel provided by the present invention has a dielectric constant of no more than 1.20. Therefore, in electronic and electrical applications, the polyimide aerogel has a weak polarization response to the electric field, reducing the capacitance effect in signal transmission, thereby reducing signal delay and energy loss, and improving signal transmission speed and efficiency. At the same time, the thermal conductivity of the polyimide aerogel is no more than 0.022 W / (m·K), so its heat conduction ability is poor, which can effectively prevent heat transfer and maintain the thermal stability of the system.

[0072] Based on the above reasons, the polyimide aerogel of the present invention has good insulation effect and excellent heat insulation effect, and is suitable for the field of microelectronic devices requiring heat management.

[0073] It is understood that the polyimide aerogel of the present invention is not limited to use in the field of microelectronic devices, but is also applicable to other fields that require light weight, low dielectric constant, and thermal insulation, such as aerospace, energy storage devices, sensors, industrial thermal insulation and other fields.

[0074] Illustratively, the thermal conductivity of the polyimide aerogel is any value among 0.022W / (m·K), 0.021W / (m·K), 0.020W / (m·K), 0.019W / (m·K), 0.018W / (m·K), 0.017W / (m·K), 0.016W / (m·K), 0.015W / (m·K), 0.014W / (m·K), 0.013W / (m·K), 0.012W / (m·K), 0.011W / (m·K), 0.010W / (m·K), etc., or a range consisting of any two of the values.

[0075] Illustratively, the dielectric constant of the polyimide aerogel is any value among 1.20, 1.19, 1.18, 1.17, 1.16, 1.15, 1.14, 1.13, 1.12, 1.11, 1.10, etc., or a range consisting of any two of the values.

[0076] In some embodiments, the thermal conductivity of the polyimide aerogel may be tested according to the method described in GB / T29313-2012; the dielectric constant may be tested according to the method described in ASTM D150-18.

[0077] The polyimide aerogel may be in any form such as a film, a fiber, a block, or an irregular three-dimensional structure, and the present invention does not impose any particular limitation thereto.

[0078] In one embodiment, the density of the polyimide aerogel is not higher than 0.12 g / cm 3 .

[0079] Among them, when the density of the polyimide aerogel is within the above range, it helps to reduce the mass of the target part, which is particularly important in applications that require weight reduction (such as aerospace and automotive industries).

[0080] For example, the density of polyimide aerogel is 0.12 g / cm 3 , 0.11g / cm 3 , 0.10g / cm 3 , 0.09g / cm 3 , 0.08g / cm 3 , 0.07g / cm 3 , 0.06g / cm 3 , 0.05g / cm 3 Any value or a range consisting of any two of the above.

[0081] In some embodiments, the density of the polyimide aerogel may be measured by referring to the method described in JB / T 2726-1996.

[0082] In one embodiment, the porosity of the polyimide aerogel is 90%-95%.

[0083] The porosity of the polyimide aerogel is within the above range, which means that more air can be stored in the aerogel. Air is a very effective thermal insulator. Therefore, the polyimide aerogel in the above embodiment has better thermal insulation performance.

[0084] Illustratively, the porosity of the polyimide aerogel is any value among 90%, 91%, 92%, 93%, 94%, 95%, etc., or a range consisting of any two of the values.

[0085] In a specific embodiment, the pore size of the polyimide aerogel is 10 μm-40 μm.

[0086] The pores of the polyimide aerogel have a pore diameter within the above range, which can further ensure its lightweight characteristics. Moreover, since the pores can store more air, the polyimide aerogel in the above embodiment has lower thermal conductivity.

[0087] Illustratively, the pore size of the polyimide aerogel is any value of 10 μm, 12 μm, 15 μm, 17 μm, 20 μm, 22 μm, 25 μm, 27 μm, 30 μm, 32 μm, 35 μm, 37 μm, 40 μm, etc., or a range consisting of any two of the values.

[0088] In some embodiments, the testing process of the porosity and pore size of the polyimide aerogel refers to GB / T21650.1-2008.

[0089] In a specific embodiment, the polyimide aerogel is prepared by heat-treating the polyimide gel composition described in the first aspect.

[0090] In a third aspect, the present invention provides a method for preparing a polyimide aerogel, comprising the following steps:

[0091] The polyimide gel composition described in the first aspect is subjected to heat treatment to obtain the polyimide aerogel.

[0092] In the preparation process of polyimide aerogel, the drying step is one of the key steps that determine its final performance and structure. At present, the common drying methods are supercritical drying (pressure is usually 7.38MPa) and freeze drying (usually vacuum). Among them, supercritical drying and freeze drying have the following problems: ① Equipment and cost: they need to rely on high pressure or vacuum environment, the equipment cost is high and the maintenance cost is high; ② Safety hazards: high-pressure operation during supercritical drying has risks such as container rupture and medium leakage. Improper operation will seriously threaten the safety of personnel and the environment; ③ Pore structure: ice crystal growth during freeze drying can easily destroy the original pore structure of the material, which limits the porosity of the aerogel and affects its performance in application scenarios such as high-performance thermal insulation and high-efficiency adsorption.

[0093] The above preparation method can realize the preparation of polyimide aerogel with low thermal conductivity and low dielectric constant at normal pressure or near normal pressure by introducing a first additive and a second additive into the polyamic acid sol. Specifically, by adding a first additive having a proton acceptor and an amino acid second additive into the polyamic acid sol, the introduction of the two additives enables the polyamic acid molecules to form cyclic hydrogen bonds with the solvent molecules, thereby reducing the surface tension of the solvent and reducing the force of the solvent on the pore structure of the polyimide during the volatilization process of heat treatment, thereby realizing the preparation of polyimide aerogel at normal pressure or near normal pressure.

[0094] In one embodiment, the heat treatment pressure is 0.9-0.12 MPa.

[0095] Illustratively, the pressure of the heat treatment is any value among 0.9 MPa, 0.95 MPa, 0.1 MPa, 1.11 MPa, 0.12 MPa, etc., or a range consisting of any two of them.

[0096] In some embodiments, when the polyimide aerogel is a polyimide aerogel film, the method further comprises: using an open scraper to evenly coat the polyimide gel composition on a glass plate, and then placing the glass plate on a hot plate for heat treatment.

[0097] In a specific embodiment, the heat treatment includes: heating to 80-180°C at a heating rate of 10-30°C / min, keeping warm for 10-50 minutes, continuing to heat to 300-400°C, and keeping warm for a second time for 10-50 minutes.

[0098] In the above embodiment, the first heat preservation can form cyclic hydrogen bonds between polyamino acid molecules and solvent molecules, and at the same time, the solvent begins to volatilize. The second heat preservation allows the solvent, the first additive, and the second additive to function and form a polyimide aerogel with certain pores.

[0099] For example, the primary insulation temperature is any value selected from 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, etc., or a range consisting of any two of them. The primary insulation time is any value selected from 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, etc., or a range consisting of any two of them. The secondary insulation temperature is any value selected from 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, 360°C, 370°C, 380°C, 390°C, 400°C, etc., or a range consisting of any two of them. The secondary insulation time is any value selected from 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, etc., or a range consisting of any two of them.

[0100] In one embodiment, the polyimide gel composition is placed on a plane, and the thickness of the polyimide gel composition is measured as L0. After the heat treatment, the thickness of the polyimide aerogel is measured as L1, and L0 and L1 satisfy the following formula 1:

[0101]

[0102] The polyimide aerogel prepared from the aforementioned polyimide gel composition exhibits lower thermal conductivity and dielectric constant, making it suitable for providing insulation with lower thermal conductivity for various electronic devices, thereby reducing the risk of thermal failure. This is primarily due to the following reasons: Firstly, the aerogel's thermal insulation performance relies primarily on its highly porous structure, which effectively blocks heat conduction. Negative shrinkage, however, means an increase in aerogel volume, which alters the size and distribution of pores and, consequently, affects the heat conduction path. Secondly, the aerogel's electrical insulation performance depends primarily on its material composition and structure. This increase in volume can lead to changes in the material's internal structure, thus affecting the aerogel's dielectric constant.

[0103] In a fourth aspect, the present invention provides a thermal insulation coating comprising the polyimide gel composition described in the first aspect, or the polyimide aerogel described in the second aspect, or the polyimide aerogel prepared in the third aspect.

[0104] In a fifth aspect, the present invention provides a functional element prepared from the polyimide gel composition described in the first aspect, or prepared from the thermal insulation coating described in the fourth aspect, or including the polyimide aerogel described in the second aspect.

[0105] Since the functional element includes the above-mentioned polyimide aerogel, it has excellent insulation capabilities and good thermal insulation properties, which can help manage the heat distribution inside the device and prevent overheating and thermal runaway.

[0106] In some embodiments, the above-mentioned functional elements include but are not limited to insulation panels and insulating glass in the field of building energy conservation, insulation blankets in the field of industrial energy, insulation parts for engine compartments and battery packs in the field of transportation vehicles, thermal control systems and protective clothing in the field of aerospace, heat sinks and insulation components of electronic appliances in the field of home appliances, and other functional elements.

[0107] In some embodiments, the functional element is at least one of a thermal insulation layer, an insulating layer, and an insulating shell.

[0108] In a sixth aspect, the present invention provides an electronic device comprising the functional element described in the fifth aspect.

[0109] Since the electronic device includes the above functional elements, it has excellent safety and stability.

[0110] To further understand the present invention, the following will clearly and completely describe the technical solutions of the present invention in conjunction with specific embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0111] Unless otherwise specified, all reagents involved in the embodiments of the present invention are commercially available products and can be purchased through commercial channels.

[0112] Example 1

[0113] This example provides a polyimide gel composition, comprising: p-phenylenediamine, N,N-dimethylacetamide, 3,3',4,4'-biphenyltetracarboxylic dianhydride, triethylamine, and serine; based on the molar amount of 3,3',4,4'-biphenyltetracarboxylic dianhydride as 100%, triethylamine accounts for 33% of 3,3',4,4'-biphenyltetracarboxylic dianhydride; and serine accounts for 0.01% of 3,3',4,4'-biphenyltetracarboxylic dianhydride.

[0114] This example also provides a polyimide aerogel film and a preparation method thereof, wherein the preparation method comprises the steps of using the polyimide provided in the above example, specifically comprising the following steps:

[0115] ① Weigh p-phenylenediamine, N,N-dimethylacetamide, and 3,3',4,4'-biphenyltetracarboxylic dianhydride in a mass ratio of 1:4.2:0.8;

[0116] ② At room temperature, add p-phenylenediamine to N,N-dimethylacetamide and stir for 10 minutes to dissolve it; then add 3,3',4,4'-biphenyltetracarboxylic dianhydride and continue stirring for 6 hours to obtain a polyamic acid sol;

[0117] ③ Based on the molar amount of 3,3',4,4'-biphenyltetracarboxylic dianhydride as 100%, 33% triethylamine and 0.01% serine were added to the polyamic acid sol, and stirring was continued for 7 hours to obtain a polyimide gel composition;

[0118] ④ Use a scraper with an opening thickness of 100 μm to evenly coat the polyimide gel composition on a glass plate. Use a Mitutoyo 0-0.25 mm industrial-grade high-precision digital micrometer to measure the initial thickness (mm) of the composition on the glass plate, which is recorded as L0. Place the glass plate covered with the composite sol on a hot plate and heat it to 120°C at a heating rate of 20°C / min, keep it warm for 35 minutes, and then heat it to 340°C and keep it warm for 15 minutes to obtain a polyimide aerogel film. Its SEM image is shown in the attached figure. Figure 1 As shown, the thickness (mm) of the polyimide aerogel film was measured using a Mitutoyo 0-0.25 mm industrial-grade high-precision digital micrometer, which was recorded as L1.

[0119] Example 2

[0120] This example provides a polyimide gel composition, the differences between which and Example 1 are shown in Table 1; this example also provides a polyimide aerogel film and a preparation method, the preparation method comprising the following steps:

[0121] ① Weigh 2,2-bis(4-aminophenyl)hexafluoropropane, N,N-dimethylformamide, and hexafluorodianhydride in a mass ratio of 1:5.1:1.2;

[0122] ② At room temperature, add 2,2-bis(4-aminophenyl)hexafluoropropane to N,N-dimethylformamide and stir for 10 minutes to dissolve it; then add hexafluorodianhydride and continue stirring for 9 hours to obtain a polyamic acid sol;

[0123] ③ Based on the molar amount of hexafluorodianhydride as 100%, 28% pyridine and 0.03% cysteine ​​were added to the polyamic acid sol, and stirring was continued for 5 hours to obtain a polyimide gel composition;

[0124] ④ Use a scraper with an opening thickness of 100 μm to evenly coat the polyimide gel composition on a glass plate, and use a Mitutoyo 0-0.25 mm industrial-grade high-precision digital micrometer to measure the initial thickness (mm) of the composition on the glass plate, which is recorded as L0; place the glass plate covered with the composite sol on a hot table, heat it to 150°C at a heating rate of 20°C / min and keep it warm for 40 minutes, and then heat it to 350°C and keep it warm for 10 minutes to obtain a polyimide aerogel film. Use a Mitutoyo 0-0.25 mm industrial-grade high-precision digital micrometer to measure the thickness (mm) of the polyimide aerogel film, which is recorded as L1.

[0125] Example 3

[0126] This example provides a polyimide gel composition, the differences between which and Example 1 are shown in Table 1; this example also provides a polyimide aerogel film and a preparation method, the preparation method comprising the following steps:

[0127] ① Weigh 4,4'-diaminodiphenyl ether, N-methylpyrrolidone and 4,4'-oxydiphthalic anhydride in a mass ratio of 1:6:1.6;

[0128] ② At room temperature, add 4,4'-diaminodiphenyl ether to N-methylpyrrolidone and stir for 20 minutes to dissolve it; then add 4,4'-oxydiphthalic anhydride and continue stirring for 9 hours to obtain a polyamic acid sol;

[0129] ③ At room temperature, based on a molar amount of 4,4'-oxydiphthalic anhydride as 100%, 35% isoquinoline and 0.02% proline were added to the polyamic acid sol and stirred for 6 hours to obtain a polyimide gel composition;

[0130] ④ Use a scraper with an opening thickness of 200 μm to evenly coat the polyimide gel composition on a glass plate, and use a Mitutoyo 0-0.25 mm industrial-grade high-precision digital micrometer to measure the initial thickness (mm) of the composition on the glass plate, which is recorded as L0; place the glass plate covered with the composite sol on a hot table, heat it to 160°C at a heating rate of 20°C / min and keep it warm for 30 minutes, and then heat it to 340°C and keep it warm for 20 minutes to obtain a polyimide aerogel film. Use a Mitutoyo 0-0.25 mm industrial-grade high-precision digital micrometer to measure the thickness (mm) of the polyimide aerogel film, which is recorded as L1.

[0131] Example 4

[0132] This example provides a polyimide gel composition, the differences between which and Example 1 are shown in Table 1; this example also provides a polyimide aerogel film and a preparation method, the preparation method comprising the following steps:

[0133] ① Weigh 2,2'-bis(trifluoromethyl)diaminobiphenyl, N,N-dimethylacetamide, and bisphenol A diether dianhydride in a mass ratio of 1:3.7:0.9;

[0134] ② At room temperature, add 2,2'-bis(trifluoromethyl)diaminobiphenyl to N,N-dimethylacetamide and stir for 10 minutes to dissolve it; then add bisphenol A diether dianhydride and continue stirring for 6 hours to obtain a polyamic acid sol;

[0135] ③ At room temperature, based on the molar amount of bisphenol A diether dianhydride as 100%, 50% trimethylphosphine and 0.08% arginine were added to the polyamic acid sol and stirred for 8 hours to obtain a polyimide gel composition;

[0136] ④ Use a scraper with an opening thickness of 100 μm to evenly coat the polyimide gel composition on a glass plate, and use a Mitutoyo 0-0.25 mm industrial-grade high-precision digital micrometer to measure the initial thickness (mm) of the composition on the glass plate, which is recorded as L0; place the glass plate covered with the composite sol on a hot table, heat it to 120°C at a heating rate of 20°C / min and keep it warm for 45 minutes, and then heat it to 340°C and keep it warm for 15 minutes to obtain a polyimide aerogel film. Use a Mitutoyo 0-0.25 mm industrial-grade high-precision digital micrometer to measure the thickness (mm) of the polyimide aerogel film, which is recorded as L1.

[0137] Example 5

[0138] This example provides a polyimide gel composition, the differences between which and Example 1 are shown in Table 1; this example also provides a polyimide aerogel film and a preparation method, the preparation method comprising the following steps:

[0139] ① Weigh 4,4'-diaminodiphenyl ether, N,N-dimethylformamide and hexafluorodianhydride in a mass ratio of 1:4.8:1.2;

[0140] ② At room temperature, add 4,4'-diaminodiphenyl ether to N,N-dimethylformamide and stir for 10 minutes to dissolve it; then add hexafluorodianhydride and continue stirring for 9 hours to obtain a polyamic acid sol;

[0141] ③ At room temperature, based on the molar amount of hexafluorodianhydride as 100%, 28% pyridine and 0.05% tryptophan were added to the polyamic acid sol and stirred for 5 hours to obtain a polyimide gel composition;

[0142] ④ Use a scraper with an opening thickness of 75 μm to evenly coat the polyimide gel composition on a glass plate, and use a Mitutoyo 0-0.25 mm industrial-grade high-precision digital micrometer to measure the initial thickness (mm) of the composition on the glass plate, which is recorded as L0; place the glass plate covered with the composite sol on a hot table, heat it to 160°C at a heating rate of 20°C / min and keep it warm for 35 minutes, and then heat it to 340°C and keep it warm for 25 minutes to obtain a polyimide aerogel film. Use a Mitutoyo 0-0.25 mm industrial-grade high-precision digital micrometer to measure the thickness (mm) of the polyimide aerogel film, which is recorded as L1.

[0143] Example 6

[0144] This example provides a polyimide gel composition, the differences between which and Example 1 are shown in Table 1; this example also provides a polyimide aerogel film and a preparation method, the preparation method comprising the following steps:

[0145] ① Weigh 2,2-bis(4-hydroxy-3-aminophenyl)propane, N-methylpyrrolidone, and pyromellitic dianhydride in a mass ratio of 1:6:1.6;

[0146] ② At room temperature, add 2,2-bis(4-hydroxy-3-aminophenyl)propane to N-methylpyrrolidone and stir for 10 minutes to dissolve it; then add pyromellitic dianhydride and continue stirring for 7 hours to obtain a polyamic acid sol;

[0147] ③ At room temperature, based on the molar amount of pyromellitic dianhydride as 100%, 35% isoquinoline and 0.07% cysteine ​​were added to the polyamic acid sol and stirred for 6 hours to obtain a polyimide gel composition;

[0148] ④ Use a scraper with an opening thickness of 200 μm to evenly coat the polyimide gel composition on a glass plate, and use a Mitutoyo 0-0.25 mm industrial-grade high-precision digital micrometer to measure the initial thickness (mm) of the composition on the glass plate, which is recorded as L0; place the glass plate coated with the composition on a hot table, heat it to 170°C at a heating rate of 20°C / min and keep it warm for 25 minutes, and then heat it to 340°C and keep it warm for 35 minutes to obtain a polyimide aerogel film. Use a Mitutoyo 0-0.25 mm industrial-grade high-precision digital micrometer to measure the thickness (mm) of the polyimide aerogel film, which is recorded as L1.

[0149] Example 7

[0150] This example provides a polyimide gel composition, the differences between which and Example 3 are shown in Table 1; the difference between the preparation of the polyimide aerogel film and Example 3 is that in step ③, 60% isoquinoline and 0.1% proline are added to the polyamic acid sol and stirring is continued for 6 hours to obtain a composite sol.

[0151] Example 8

[0152] This example provides a polyimide gel composition, the differences between which and Example 3 are shown in Table 1; the difference between the preparation of the polyimide aerogel film and Example 3 is that in step ③, 5% isoquinoline and 0.005% proline are added to the polyamic acid sol and stirring is continued for 6 hours to obtain a composite sol.

[0153] Example 9

[0154] This example provides a polyimide gel composition, the differences between which and Example 3 are shown in Table 1; the difference between the preparation of the polyimide aerogel film and Example 3 is that in step ③, 30% isoquinoline and 0.05% proline are added to the polyamic acid sol and stirring is continued for 6 hours to obtain a composite sol.

[0155] Example 10

[0156] This example provides a polyimide gel composition, the differences between which and Example 3 are shown in Table 1; the difference between the preparation of the polyimide aerogel film and Example 3 is that: in step ③, 10% isoquinoline and 0.01% proline are added to the polyamic acid sol and stirring is continued for 6 hours to obtain a composite sol.

[0157] Comparative Example 1

[0158] This example provides a polyimide gel composition, which differs from Example 1 only in that triethylamine and serine are not added.

[0159] This example also provides a polyimide aerogel film and a preparation method thereof. The preparation method thereof differs from that of Example 1 only in that triethylamine and serine are not added.

[0160] Comparative Example 2

[0161] This example provides a polyimide gel composition, which differs from Example 2 only in that pyridine and cysteine ​​are not added.

[0162] This example also provides a polyimide aerogel film and a preparation method thereof. The preparation method thereof differs from that of Example 2 only in that pyridine and cysteine ​​are not added.

[0163] Comparative Example 3

[0164] This example provides a polyimide gel composition, which differs from Example 3 only in that isoquinoline and proline are not added.

[0165] This example also provides a polyimide aerogel film and a preparation method thereof. The preparation method thereof differs from that of Example 3 only in that isoquinoline and proline are not added.

[0166] Comparative Example 4

[0167] This example provides a polyimide gel composition, which differs from Example 4 only in that trimethylphosphine and arginine are not added.

[0168] This example also provides a polyimide aerogel membrane and a preparation method thereof. The preparation method thereof differs from that of Example 4 only in that trimethylphosphine and arginine are not added.

[0169] Comparative Example 5

[0170] This example provides a polyimide gel composition, which differs from Example 5 only in that pyridine and tryptophan are not added.

[0171] This example also provides a polyimide aerogel film and a preparation method thereof. The preparation method thereof differs from that of Example 5 only in that pyridine and tryptophan are not added.

[0172] Comparative Example 6

[0173] This example provides a polyimide gel composition, which differs from Example 6 only in that isoquinoline and cysteine ​​are not added.

[0174] This example also provides a polyimide aerogel membrane and a preparation method thereof. The preparation method thereof differs from that of Example 6 only in that isoquinoline and cysteine ​​are not added.

[0175] Comparative Example 7

[0176] This example provides a polyimide gel composition, which differs from Example 1 only in that triethylamine is not added.

[0177] This example also provides a polyimide aerogel film and a preparation method thereof. The preparation method thereof differs from that of Example 1 only in that triethylamine is not added.

[0178] Comparative Example 8

[0179] This example provides a polyimide gel composition, which differs from Example 1 only in that serine is not added.

[0180] This example also provides a polyimide aerogel film and a preparation method thereof. The preparation method thereof differs from that of Example 1 only in that serine is not added.

[0181] Test Case

[0182] The polyimide aerogel films obtained from the above examples and comparative examples were subjected to the following tests:

[0183] Density test: Reference standard JB / T 2726-1996;

[0184] Thermal conductivity test: Reference standard GB / T 29313-2012;

[0185] Dielectric constant: Reference standard ASTM D150-18;

[0186] Shrinkage ε (%): The shrinkage of the polyimide aerogel film was calculated according to Formula 1.

[0187]

[0188] Porosity: Reference standard GB / T 21650.1-2008;

[0189] Aperture: Refer to standard GB / T 21650.1-2008.

[0190] The test results are shown in Table 1.

[0191]

[0192]

[0193] In the table, “ / ” represents a pore size less than 1 μm.

[0194] As shown in Table 1, compared with the comparative example, the polyimide aerogel film of the embodiment has a negative shrinkage rate, a larger pore size, a higher porosity, and a lower density, and therefore has a lower dielectric constant and thermal conductivity.

[0195] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A polyimide gel composition, characterized in that: include: Polyamic acid sol, a first additive, and a second additive, wherein the first additive includes a proton acceptor compound, and the second additive includes an amino acid compound.

2. The polyimide gel composition according to claim 1, wherein The proton acceptor compound includes a nitrogen-containing compound and / or a phosphine-based compound.

3. The polyimide gel composition according to claim 2, characterized in that The nitrogen-containing compound includes an amino compound and / or a nitrogen heterocyclic compound.

4. The polyimide gel composition according to claim 3, characterized in that The amino compound includes at least one of methylamine, urea, ethylamine, ethanolamine, ethylenediamine, dimethylamine, trimethylamine, triethylamine, propylamine, isopropylamine, 1,3-propylenediamine, 1,2-propylenediamine, tripropylamine, triethanolamine, butylamine, isobutylamine, tert-butylamine, hexylamine, octylamine, aniline, benzylamine, cyclohexylamine, hexamethylenetetramine, o-toluidine, m-toluidine, p-toluidine, diphenylamine, and benzidine; And / or, the nitrogen heterocyclic compound includes at least one of quinoline, isoquinoline, pyridine, and 3-methylpyridine.

5. The polyimide gel composition according to any one of claims 2 to 4, characterized in that: The phosphine-based compound includes at least one of trimethylphosphine, triethylphosphine and tripropylphosphine.

6. The polyimide gel composition according to any one of claims 1 to 5, characterized in that: The amino acid compounds include: glycine, alanine, valine, leucine, isoleucine, methionine (methionine), proline, tryptophan, serine, tyrosine, cysteine, phenylalanine, asparagine, glutamine, threonine, aspartic acid, glutamic acid, lysine, arginine and histidine, β-alanine, γ-aminobutyric acid, L-homoarginine, L-citrulline, L-ornithine, L-hydroxyproline, L-alloleucine, L-norvaline, L-selenocysteine, L- At least one of pyrrolysine, D-alanine, D-glutamic acid, D-serine, L-theanine, L-anserine, L-carnosine, L-kynurenine, L-3-methylhistidine, L-homocysteine, L-homoserine, L-p-hydroxyphenylglycine, L-m-hydroxyphenylglycine, L-o-hydroxyphenylglycine, L-phenylglycine, L-cyclopropylglycine, L-cyclobutylglycine, L-cyclopentylglycine, L-cyclohexylglycine, L-2-aminobutyric acid, and L-3-aminobutyric acid.

7. The polyimide gel composition according to any one of claims 1 to 6, characterized in that: The polyamic acid sol is obtained by polymerizing a raw material system including dianhydride monomers and diamine monomers.

8. The polyimide gel composition according to claim 7, characterized in that The first additive is 5%-60% of the molar amount of the dianhydride monomer; and / or the second additive is 0.005%-0.10% of the molar amount of the dianhydride monomer.

9. The polyimide gel composition according to claim 8, characterized in that The first additive is 10%-30% of the molar amount of the dianhydride monomer; and / or the second additive is 0.01%-0.05% of the molar amount of the dianhydride monomer.

10. The polyimide gel composition according to any one of claims 1 to 9, characterized in that: The composition also includes a solvent, which includes one or more of N,N-dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, N-ethylpyrrolidone, N-propylpyrrolidone, N-butylpyrrolidone, N-cyclohexylpyrrolidone, N-benzylpyrrolidone, N,N-diethylformamide, 1,3-dimethyl-2-imidazolidinone, tetrahydrofuran, dimethyl sulfoxide, p-chlorophenol, 1,3-dimethyl-2-imidazolidinone, diphenyl sulfone, 4,4'-dimethyldiphenyl sulfone, 4,4'-dichlorodiphenyl sulfone, methyl phenyl sulfoxide, diethyl sulfone, dipropyl sulfone, dibutyl sulfone, trifluoromethylphenyl sulfoxide, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl acetate, ethyl acetate, γ-butyrolactone, hexafluoroisopropanol, methyl benzoate, and ethyl benzoate.

11. A polyimide aerogel, characterized in that: The polyimide gel composition is prepared from any one of claims 1 to 10.

12. The polyimide aerogel according to claim 11, characterized in that The thermal conductivity of the polyimide aerogel is not higher than 0.022 W / (m·K), and the dielectric constant is not greater than 1.

20.

13. The polyimide aerogel according to claim 11 or 12, characterized in that: The density of the polyimide aerogel is not higher than 0.12 g / cm 3 ; And / or, the porosity of the polyimide aerogel is 90%-95%; And / or, the pore size of the polyimide aerogel is 10 μm-40 μm.

14. The polyimide aerogel according to any one of claims 11 to 13, characterized in that: The polyimide gel composition is prepared by heat treatment of the polyimide gel composition according to any one of claims 1 to 10.

15. A method for preparing a polyimide aerogel, characterized in that: The following steps are involved: The polyimide gel composition according to any one of claims 1 to 10 is subjected to heat treatment to obtain the polyimide aerogel.

16. The preparation method according to claim 15, characterized in that The heat treatment pressure is 0.9-0.12Mpa; And / or, the heat treatment further includes: heating to 80°C-180°C at a heating rate of 10°C / min-30°C / min, keeping the temperature for 10min-50min, continuing to heat to 300°C-400°C, and keeping the temperature for a second time for 10min-50min.

17. The preparation method according to any one of claims 15 or 16, characterized in that The thickness of the polyimide gel composition is measured as L0. After the heat treatment, the thickness of the polyimide aerogel is measured as L1. L0 and L1 satisfy the following formula 1:

18. A thermal insulation coating, characterized in that: The invention comprises the polyimide gel composition according to any one of claims 1 to 10, or the polyimide aerogel according to any one of claims 11 to 14, or the polyimide aerogel prepared by the preparation method according to any one of claims 15 to 17.

19. A functional element, characterized in that: It is prepared from the polyimide gel composition according to any one of claims 1 to 10, or prepared from the thermal insulation coating according to claim 18, or includes the polyimide aerogel according to any one of claims 11 to 14.

20. The functional element according to claim 19, characterized in that The functional element is at least one of a heat insulation layer, an insulating layer, and an insulating shell.

21. An electronic device, characterized in that: Comprising the functional element according to claim 19 or 20.

Images