Preparation method of insulating high-temperature-resistant polyimide-ceramic composite material

Abstract

The application relates to a preparation method of an insulating high-temperature-resistant polyimide-ceramic composite material, wherein modified ceramic filler 1 and modified ceramic filler 2 are added, the ceramic filler 1 is selected from one or more of silicon nitride and boron nitride, and the ceramic filler 2 is selected from one or more of spherical alumina and spherical zirconia. The modified ceramic filler 1 introduces imide groups and benzene rings, can improve the compatibility with a polyimide matrix, and promotes uniform distribution of components; the imide groups introduced by the modified ceramic filler 2 further improve the compatibility of components, and the ceramic filler 2 is all spherical, and the spherical structure can provide better fluidity; in addition, crosslinking of the modified ceramic filler 1, the modified ceramic filler 2 and phthalic anhydride not only improves the compatibility, but also improves the mechanical properties; the components synergistically work together to improve various performances of the composite material.

Description

Technical Field

[0001] This invention relates to the field of composite material technology, and in particular to a method for preparing an insulating and high-temperature resistant polyimide-ceramic composite material. Background Technology

[0002] Polyimide, abbreviated as PI, is a class of high molecular polymers containing an imide ring structure, which have good properties such as high temperature resistance, insulation properties, mechanical properties, and chemical stability.

[0003] Traditional synthetic routes for polyimides mainly include one-step and two-step methods. The one-step method involves the direct polycondensation reaction of dianhydride and diamine in a high-boiling-point solvent or solvent-free system at high temperature, while simultaneously dehydrating and closing the ring to form PI. The water generated during the reaction is removed by azeotropic distillation or inert gas purging. The two-step method involves the nucleophilic addition-polycondensation reaction of dianhydride and diamine in a solvent at low temperature to generate linear polyamic acid. Then, the polyamic acid forms an imide ring through "dehydration and ring closure", thus completing the preparation of PI.

[0004] Polyimide has a wide range of applications, including: in the electronics and semiconductor fields, it is used as a substrate material for flexible sensors, flexible printed circuit boards (FPCs), and interlayer insulating films for integrated circuits (ICs); in the new energy field, it is used for cell coating, battery pack separators, and high-frequency transformers; in the aerospace and military fields, it is used for engine nacelle liners, wing leading edge coatings, and insulating layers for electronic equipment in satellites and missiles; and in the medical and health fields, it is used for the housing of surgical instruments (such as laparoscopic instruments) and insulating components for medical imaging equipment (such as CT and MRI).

[0005] Currently, to improve the solubility, transparency, thermal conductivity, and other properties of traditional PI, or to expand its functional applications, modified synthetic routes are often developed through molecular design or process innovation. Novel modification routes include: copolymerization modification, which involves copolymerizing two or more dianhydrides and diamine monomers; crosslinking modification, which involves introducing crosslinkable groups into the molecular chain, causing crosslinking reactions during synthesis or subsequent processing to form a three-dimensional network structure; and the introduction of functional monomers, which involves selecting monomers with specific functions and directly introducing functional groups into the PI molecular chain, etc.

[0006] Although there are many methods for synthesizing polyimide, existing products still have some problems as market demands for products continue to increase. For example, the insulation cannot meet the requirements, leading to short circuits, electric arcs, and interference with signal transmission; the high-temperature resistance is insufficient, resulting in material softening, shrinkage, or even melting, and a significant decrease in mechanical properties.

[0007] In conclusion, it is necessary to develop a new technical solution to address the shortcomings of existing technologies. Summary of the Invention

[0008] This invention provides a method for preparing an insulating high-temperature resistant polyimide-ceramic composite material. The insulating high-temperature resistant polyimide-ceramic composite material incorporates modified ceramic filler 1 and modified ceramic filler 2. The active groups introduced by modified ceramic filler 1 and modified ceramic filler 2 improve the compatibility of the components. Furthermore, the ceramic filler 2 is spherical, and the spherical structure provides better flowability, thereby further improving the compatibility of the components. In addition, modified ceramic filler 1 and modified ceramic filler 2 can also crosslink with pyromellitic dianhydride, which not only improves compatibility but also enhances the overall performance of the composite material.

[0009] The purpose of this invention is to provide a method for preparing an insulating high-temperature resistant polyimide-ceramic composite material, the method comprising the following steps:

[0010] S1. Hydroxylation of ceramic filler 1 is performed to obtain hydroxylated ceramic filler 1;

[0011] S2. The hydroxylated ceramic filler 1 and KH570 are blended together and heated and stirred to react, thereby obtaining intermediate product 1.

[0012] S3. Under an inert atmosphere, the intermediate product 1, N-allylmaleimide, styrene, acrylamide, and initiator are blended and heated and stirred to obtain modified ceramic filler 1.

[0013] S4. Blend ceramic filler 2 and ethanol together and sonicate to obtain an ethanol solution of ceramic filler 2.

[0014] S5. The ethanol solution of the ceramic filler 2 and KH570 are mixed and heated and stirred to react, thereby obtaining intermediate product 2.

[0015] S6. Under an inert atmosphere, the intermediate product 2, N-allylmaleimide, acrylamide, and initiator are blended and heated and stirred to obtain modified ceramic filler 2.

[0016] S7. Under an inert atmosphere, diaminodiphenyl ether, pyromellitic dianhydride, modified ceramic filler 1, and modified ceramic filler 2 are mixed and heated and stirred to obtain a mixed solution.

[0017] S8. The mixture is coated onto the substrate, heated, demolded, and dried to obtain the insulating high-temperature resistant polyimide-ceramic composite material.

[0018] Furthermore, the ceramic filler 1 is selected from one or more of silicon nitride and boron nitride.

[0019] Furthermore, the ceramic filler 2 is selected from one or more of spherical alumina and spherical zirconium oxide.

[0020] Further, in step S2, the mass ratio of the hydroxylated ceramic filler 1 to KH570 is 1:(1-2).

[0021] Further, in step S3, the mass ratio of intermediate product 1, N-allyl maleimide, styrene, and acrylamide is 1:(1-3):(1-3):(1-3).

[0022] Further, in step S4, the mass ratio of the ceramic filler 2 to ethanol is 1:(30-70).

[0023] Further, in step S5, the mass ratio of the ethanol solution and KH570 of the ceramic filler 2 is 50:(8-12).

[0024] Further, in step S6, the mass ratio of intermediate product 2, N-allylmaleimide, and acrylamide is 1:(1-3):(1-3).

[0025] Further, in step S7, the mass ratio of the diaminodiphenyl ether, pyromellitic dianhydride, modified ceramic filler 1, and modified ceramic filler 2 is (10-20):(10-20):(0.1-0.3):(0.1-0.3).

[0026] The present invention has the following beneficial effects:

[0027] This invention provides a method for preparing an insulating high-temperature resistant polyimide-ceramic composite material. The insulating high-temperature resistant polyimide-ceramic composite material incorporates modified ceramic filler 1 and modified ceramic filler 2. Specifically, modified ceramic filler 1 first introduces double bonds on its surface by hydroxylating, and then polymerizes with N-allylmaleimide, styrene, and acrylamide, thereby introducing imide groups, benzene rings, and amino groups. Modified ceramic filler 2 first introduces double bonds on its surface, and then polymerizes with N-allylmaleimide and acrylamide, thereby introducing imide groups and amino groups. Finally, the amino groups on the surfaces of modified ceramic filler 1 and modified ceramic filler 2 can react with pyromellitic dianhydride to achieve crosslinking.

[0028] The imide groups and benzene rings introduced into modified ceramic filler 1 can improve compatibility with the polyimide matrix, promote uniform distribution of components, and avoid agglomeration. The imide groups introduced into modified ceramic filler 2 further improve the compatibility of components, and all ceramic fillers 2 are spherical, which provides better flowability and makes the modified ceramic filler 2 more uniform during mixing. In addition, the crosslinking of modified ceramic filler 1, modified ceramic filler 2, and pyromellitic dianhydride not only improves compatibility but also improves mechanical properties. The synergistic effect of the components improves the insulation, heat resistance, mechanical properties, thermal conductivity, and other properties of the composite material. Detailed Implementation

[0029] To more clearly illustrate the technical solution of the present invention, the following embodiments are provided. Unless otherwise stated, the raw materials, reactions, and post-processing methods appearing in the embodiments are all commercially available raw materials and technical methods well known to those skilled in the art.

[0030] The terms "preferred," "more preferably," and "more suitable" used in this invention refer to embodiments of the invention that provide certain beneficial effects under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are unavailable, nor is it intended to exclude other embodiments from the scope of this invention.

[0031] It should be understood that, except in any operational instance or otherwise indicated, the amounts or all figures representing ingredients used, for example, in the specification and claims, should be understood to be modified by the term "about" in all cases. Therefore, unless otherwise stated, the numerical parameters set forth in the following specification and appended claims are approximate values ​​varying according to the desired performance to be obtained according to the invention.

[0032] The embodiments of the present invention use the following raw materials:

[0033] Ceramic filler 1 is silicon nitride with a particle size of 20nm, purchased from Aladdin Biochemical Technology Co., Ltd.

[0034] The ceramic filler 2 is spherical alumina with a particle size of 1μm, purchased from Suzhou Yuante New Materials Co., Ltd.

[0035] The initiator is benzoyl peroxide.

[0036] Example 1

[0037] A method for preparing an insulating high-temperature resistant polyimide-ceramic composite material, comprising the following steps:

[0038] S1. Ceramic filler 1 and 30wt% hydrogen peroxide solution are mixed at a mass ratio of 1:20, stirred for 6 hours, centrifuged, washed and dried to obtain hydroxylated ceramic filler 1.

[0039] S2. The hydroxylated ceramic filler 1, KH570, ethanol and water are mixed in a mass ratio of 1:1.5:20:4, sonicated for 20 min, pH adjusted to 5 with glacial acetic acid, heated to 80°C and stirred for 3 h, centrifuged, washed and dried to obtain intermediate product 1.

[0040] S3. Under a nitrogen atmosphere, the intermediate product 1, N-allylmaleimide, styrene, acrylamide, initiator, and solvent xylene are mixed in a mass ratio of 1:1:1:2:0.3:25, heated to 90°C and stirred for 10 hours. After centrifugation, washing, and drying, modified ceramic filler 1 is obtained.

[0041] S4. Dry the ceramic filler 2 at 100℃ for 10h, then mix it with ethanol at a mass ratio of 1:50 and sonicate for 30min to obtain an ethanol solution of the ceramic filler 2.

[0042] S5. The ethanol solution, KH570 and water of the ceramic filler 2 are mixed in a mass ratio of 50:8:11, sonicated for 20 min, the pH is adjusted to 5 with glacial acetic acid, heated to 80°C and stirred for 3 h, centrifuged, washed and dried to obtain intermediate product 2.

[0043] S6. Under a nitrogen atmosphere, the intermediate product 2, N-allylmaleimide, acrylamide, initiator, and solvent xylene are mixed in a mass ratio of 1:1:2:0.2:20, heated to 90°C and stirred for 10 hours, centrifuged, washed, and dried to obtain modified ceramic filler 2.

[0044] S7. Under a nitrogen atmosphere, diaminodiphenyl ether, the modified ceramic filler 1, the modified ceramic filler 2, and the solvent N,N-dimethylacetamide are mixed in a mass ratio of 10:0.2:0.2:200 and stirred until the diaminodiphenyl ether is completely dissolved. Then, pyromellitic dianhydride (the mass ratio of diaminodiphenyl ether to pyromellitic dianhydride is 10:11) is added, and the mixture is heated to 35°C and stirred for 4 hours to obtain a mixed solution.

[0045] S8. The mixture is allowed to stand at 10°C for 12 hours to eliminate air bubbles. Then, it is coated onto a glass substrate with a coating thickness of 30 μm. The glass substrate is then placed in an oven and heated to 60°C at a rate of 2°C / min under a nitrogen atmosphere. The temperature is maintained at 60°C for 60 min, then heated to 300°C at a rate of 2°C / min and maintained at 300°C for 120 min. The mixture is then allowed to cool naturally to room temperature. The glass substrate is then removed and boiled in deionized water until the film peels off. The resulting film is then dried to obtain the insulating high-temperature resistant polyimide-ceramic composite material.

[0046] Example 2

[0047] A method for preparing an insulating high-temperature resistant polyimide-ceramic composite material, comprising the following steps:

[0048] S1. Ceramic filler 1 and 30wt% hydrogen peroxide solution are mixed at a mass ratio of 1:20, stirred for 6 hours, centrifuged, washed and dried to obtain hydroxylated ceramic filler 1.

[0049] S2. The hydroxylated ceramic filler 1, KH570, ethanol and water are mixed in a mass ratio of 1:1.5:20:4, sonicated for 25 min, pH adjusted to 5 with glacial acetic acid, heated to 80°C and stirred for 3 h, centrifuged, washed and dried to obtain intermediate product 1.

[0050] S3. Under a nitrogen atmosphere, the intermediate product 1, N-allylmaleimide, styrene, acrylamide, initiator, and solvent xylene are mixed in a mass ratio of 1:1:1:2:0.3:25, heated to 90°C and stirred for 10 hours. After centrifugation, washing, and drying, modified ceramic filler 1 is obtained.

[0051] S4. Dry the ceramic filler 2 at 100℃ for 10h, then mix it with ethanol at a mass ratio of 1:50 and sonicate for 30min to obtain an ethanol solution of the ceramic filler 2.

[0052] S5. The ethanol solution, KH570 and water of the ceramic filler 2 are mixed in a mass ratio of 50:8:11, sonicated for 20 min, the pH is adjusted to 5 with glacial acetic acid, heated to 80°C and stirred for 3 h, centrifuged, washed and dried to obtain intermediate product 2.

[0053] S6. Under a nitrogen atmosphere, the intermediate product 2, N-allylmaleimide, acrylamide, initiator, and solvent xylene are mixed in a mass ratio of 1:1:2:0.2:20, heated to 90°C and stirred for 10 hours, centrifuged, washed, and dried to obtain modified ceramic filler 2.

[0054] S7. Under a nitrogen atmosphere, diaminodiphenyl ether, the modified ceramic filler 1, the modified ceramic filler 2, and the solvent N,N-dimethylacetamide are mixed in a mass ratio of 10:0.2:0.2:200 and stirred until the diaminodiphenyl ether is completely dissolved. Then, pyromellitic dianhydride (the mass ratio of diaminodiphenyl ether to pyromellitic dianhydride is 10:11) is added, and the mixture is heated to 35°C and stirred for 4 hours to obtain a mixed solution.

[0055] S8. The mixture is allowed to stand at 10°C for 12 hours to eliminate air bubbles. Then, it is coated onto a glass substrate with a coating thickness of 30 μm. The glass substrate is then placed in an oven and heated to 60°C at a rate of 2°C / min under a nitrogen atmosphere. The temperature is maintained at 60°C for 60 min, then heated to 300°C at a rate of 2°C / min and maintained at 300°C for 120 min. The mixture is then allowed to cool naturally to room temperature. The glass substrate is then removed and boiled in deionized water until the film peels off. The resulting film is then dried to obtain the insulating high-temperature resistant polyimide-ceramic composite material.

[0056] Example 3

[0057] A method for preparing an insulating high-temperature resistant polyimide-ceramic composite material, comprising the following steps:

[0058] S1. Ceramic filler 1 and 30wt% hydrogen peroxide solution are mixed at a mass ratio of 1:20, stirred for 6 hours, centrifuged, washed and dried to obtain hydroxylated ceramic filler 1.

[0059] S2. The hydroxylated ceramic filler 1, KH570, ethanol and water are mixed in a mass ratio of 1:1.5:20:4, sonicated for 20 min, pH adjusted to 5 with glacial acetic acid, heated to 80°C and stirred for 3 h, centrifuged, washed and dried to obtain intermediate product 1.

[0060] S3. Under a nitrogen atmosphere, the intermediate product 1, N-allylmaleimide, styrene, acrylamide, initiator, and solvent xylene are mixed in a mass ratio of 1:1:1:2:0.3:25, heated to 85°C and stirred for 10 hours. After centrifugation, washing, and drying, modified ceramic filler 1 is obtained.

[0061] S4. Dry the ceramic filler 2 at 100℃ for 10h, then mix it with ethanol at a mass ratio of 1:50 and sonicate for 30min to obtain an ethanol solution of the ceramic filler 2.

[0062] S5. The ethanol solution, KH570 and water of the ceramic filler 2 are mixed in a mass ratio of 50:8:11, sonicated for 20 min, the pH is adjusted to 5 with glacial acetic acid, heated to 80°C and stirred for 3 h, centrifuged, washed and dried to obtain intermediate product 2.

[0063] S6. Under a nitrogen atmosphere, the intermediate product 2, N-allylmaleimide, acrylamide, initiator, and solvent xylene are mixed in a mass ratio of 1:1:2:0.2:20, heated to 90°C and stirred for 10 hours, centrifuged, washed, and dried to obtain modified ceramic filler 2.

[0064] S7. Under a nitrogen atmosphere, diaminodiphenyl ether, the modified ceramic filler 1, the modified ceramic filler 2, and the solvent N,N-dimethylacetamide are mixed in a mass ratio of 10:0.2:0.2:200 and stirred until the diaminodiphenyl ether is completely dissolved. Then, pyromellitic dianhydride (the mass ratio of diaminodiphenyl ether to pyromellitic dianhydride is 10:11) is added, and the mixture is heated to 35°C and stirred for 4 hours to obtain a mixed solution.

[0065] S8. The mixture is allowed to stand at 10°C for 12 hours to eliminate air bubbles. Then, it is coated onto a glass substrate with a coating thickness of 30 μm. The glass substrate is then placed in an oven and heated to 60°C at a rate of 2°C / min under a nitrogen atmosphere. The temperature is maintained at 60°C for 60 min, then heated to 300°C at a rate of 2°C / min and maintained at 300°C for 120 min. The mixture is then allowed to cool naturally to room temperature. The glass substrate is then removed and boiled in deionized water until the film peels off. The resulting film is then dried to obtain the insulating high-temperature resistant polyimide-ceramic composite material.

[0066] Comparative Example 1

[0067] The difference between Comparative Example 1 and Example 1 is that acrylamide in steps S3 and S6 is removed, while the remaining components and preparation methods are the same as in Example 1.

[0068] Comparative Example 2

[0069] The difference between Comparative Example 2 and Example 1 is that steps S1-S6 are deleted, and modified ceramic filler 1 is replaced with ceramic filler 1 and modified ceramic filler 2 is replaced with ceramic filler 2. The remaining components and preparation methods are the same as in Example 1.

[0070] Test case

[0071] The performance of the composite materials prepared in Examples 1-3 and Comparative Examples 1-2 was tested.

[0072] Test method:

[0073] Volume resistivity: Tested in accordance with GB / T 31838.2-2019.

[0074] Thermogravimetric analysis: Weigh 5-7 mg of the composite material sample and cut it into small pieces and place them in a crucible. Use a thermogravimetric analyzer (model STARe) to test the temperature from 30 °C to 800 °C at a heating rate of 10 °C / min in air atmosphere.

[0075] Mechanical properties: Tested according to GB / T 13542.2-2009, with a tensile rate of 10 mm / min.

[0076] Thermal conductivity: Tested according to ASTM D5470.

[0077] The test results are shown in Table 1.

[0078] Table 1. Test results of composite material properties

[0079]

[0080] As can be seen from Table 1, the performance of Examples 1-3 is better than that of Comparative Examples 1-2. This is because neither modified ceramic filler 1 nor modified ceramic filler 2 in Comparative Example 1 introduced amino groups, which prevented them from forming crosslinks with polyimide and reduced the compatibility of each component. As a result, the components could not form a good synergistic effect, leading to a decrease in performance. In contrast, Comparative Example 2 directly used unmodified ceramic fillers 1 and 2, which significantly reduced the compatibility of each component and made them prone to agglomeration, ultimately leading to a decrease in various performance characteristics.

[0081] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0082] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for preparing an insulating, high-temperature resistant polyimide-ceramic composite material, characterized in that, The preparation method of the insulating high-temperature resistant polyimide-ceramic composite material includes the following steps: S1. Hydroxylation of ceramic filler 1 is performed to obtain hydroxylated ceramic filler 1; S2. The hydroxylated ceramic filler 1 and KH570 are blended together and heated and stirred to react, thereby obtaining intermediate product 1. S3. Under an inert atmosphere, the intermediate product 1, N-allylmaleimide, styrene, acrylamide, and initiator are blended and heated and stirred to obtain modified ceramic filler 1. S4. Blend ceramic filler 2 and ethanol together and sonicate to obtain an ethanol solution of ceramic filler 2. S5. The ethanol solution of the ceramic filler 2 and KH570 are mixed and heated and stirred to react, thereby obtaining intermediate product 2. S6. Under an inert atmosphere, the intermediate product 2, N-allylmaleimide, acrylamide, and initiator are blended and heated and stirred to obtain modified ceramic filler 2. S7. Under an inert atmosphere, diaminodiphenyl ether, pyromellitic dianhydride, modified ceramic filler 1, and modified ceramic filler 2 are mixed and heated and stirred to obtain a mixed solution. S8. The mixture is coated onto a substrate, heated, demolded, and dried to obtain the insulating high-temperature resistant polyimide-ceramic composite material. in, The ceramic filler 1 is selected from one or more of silicon nitride and boron nitride; The ceramic filler 2 is selected from one or more of spherical alumina and spherical zirconia.

2. The method for preparing the insulating high-temperature resistant polyimide-ceramic composite material according to claim 1, characterized in that, In step S2, the mass ratio of the hydroxylated ceramic filler 1 to KH570 is 1:(1-2).

3. The method for preparing the insulating high-temperature resistant polyimide-ceramic composite material according to claim 1, characterized in that, In step S3, the mass ratio of intermediate product 1, N-allyl maleimide, styrene, and acrylamide is 1:(1-3):(1-3):(1-3).

4. The method for preparing the insulating high-temperature resistant polyimide-ceramic composite material according to claim 1, characterized in that, In step S4, the mass ratio of the ceramic filler 2 to ethanol is 1:(30-70).

5. The method for preparing the insulating high-temperature resistant polyimide-ceramic composite material according to claim 1, characterized in that, In step S5, the mass ratio of the ethanol solution and KH570 of the ceramic filler 2 is 50:(8-12).

6. The method for preparing the insulating high-temperature resistant polyimide-ceramic composite material according to claim 1, characterized in that, In step S6, the mass ratio of intermediate product 2, N-allyl maleimide, and acrylamide is 1:(1-3):(1-3).

7. The method for preparing the insulating high-temperature resistant polyimide-ceramic composite material according to claim 1, characterized in that, In step S7, the mass ratio of diaminodiphenyl ether, pyromellitic dianhydride, modified ceramic filler 1, and modified ceramic filler 2 is (10-20):(10-20):(0.1-0.3):(0.1-0.3).

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