Preparation method and application of 3D printing polyimide slurry based on photo-thermal dual curing

Abstract

The invention discloses preparation and application of 3D printing polyimide slurry based on photo-thermal dual curing, and relates to the field of polymer chemical materials. The photosensitive resin is prepared from polyamide acid, a photosensitive modifier, a cross-linking agent and a photoinitiator. The polyamide acid is formed by polymerizing aromatic tetracarboxylic dianhydride and aromatic diamine containing carboxyl functional groups; the photosensitive modifier is a (methyl) acrylate compound containing unsaturated double bonds and amino groups and is grafted on the polyamide acid to form polyamide ammonium salt, a digital light treatment photocuring and thermal amidation two-stage curing process is adopted, rapid forming of a complex structure is achieved through photocuring, and imidization reaction is completed through thermal amidation. The problems that traditional 3D printing polyimide is high in shrinkage rate and low in forming precision are solved.

Description

Technical Field

[0001] This invention relates to the field of polymer chemical materials, specifically to a method for preparing and applying 3D printing polyimide slurry based on photothermal dual curing. Background Technology

[0002] Polyimide is a high-performance polymer composed of imide units, widely used in aerospace, electronics, automotive, and chemical industries due to its excellent thermal stability, mechanical strength, and chemical resistance. However, the high thermal and chemical stability of polyimide limits the ability to process 3D structures under traditional processing conditions, concentrating polyimide manufacturing primarily in 2D forms such as thin films. With the development of 3D printing technology, researchers have added crosslinkable acrylates to the polyimide precursor framework, enabling the photosensitive precursor to crosslink and form a 3D organic gel under ultraviolet radiation. Under high-temperature heat treatment, the 3D printing material can be easily removed, and the precursor framework can be completely thermally amidated to become polyimide, achieving a leap from 2D to 3D structures for polyimide materials. Existing 3D printing technologies for polyimide, mainly using photopolymerization precursor methods, often face the problem of high shrinkage after heat treatment. Excessive shrinkage leads to low molding accuracy and structural cracking, limiting industrial applications. Therefore, developing 3D printing polyimide materials and processes with low shrinkage and high molding accuracy has become a key requirement to overcome the current technological bottlenecks. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of existing 3D printed polyimide, such as high shrinkage, low molding accuracy, and easy cracking caused by solvents, and to provide a method for preparing 3D printed polyimide slurry based on photothermal dual curing.

[0004] A 3D printing polyimide slurry based on photothermal dual curing, the raw material components of the slurry include: polyamic acid, photosensitive modifier, crosslinking agent, photoinitiator, and organic solvent; wherein, the polyamic acid is polymerized from aromatic tetracarboxylic dianhydride and aromatic diamine containing carboxyl functional groups; the photosensitive modifier is a (meth)acrylate compound containing unsaturated double bonds and amino groups, which is grafted onto the polyamic acid to form a polyamide ammonium salt; the crosslinking agent is a multifunctional (meth)acrylate crosslinking agent with a functionality of not less than 3; and the photoinitiator is an acylphosphine oxide ultraviolet photoinitiator.

[0005] The aromatic tetracarboxylic dianhydride is selected from one or more of 3,3',4,4'-benzophenone tetracarboxylic dianhydride, pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 4,4'-oxobisphthalic anhydride, or 4,4'-(hexafluoroisopropene)phthalic anhydride.

[0006] The aromatic diamine containing a carboxyl functional group is selected from one or more of 3,5-diaminobenzoic acid, 4-aminobenzoic acid-4'-aminophenyl ester, or 3,5-diaminophenylacetic acid.

[0007] The photosensitive modifier is selected from one or more of dimethylaminoethyl methacrylate, dimethylaminopropyl methacrylate, dimethylaminoethyl acrylate, diethylaminoethyl methacrylate, or diethylaminopropyl methacrylate.

[0008] The crosslinking agent is selected from one or more of trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, or trimethylolpropane trimethacrylate.

[0009] The photoinitiator is selected from one or more of diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphine, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, or bis(2,6-dimethoxybenzoyl)-(2,4,4-trimethylpentyl)phosphine oxide.

[0010] The organic solvent is one or more polar aprotic solvents selected from N,N-dimethylacetamide, N-methylpyrrolidone, N,N-dimethylformamide, or dimethyl sulfoxide.

[0011] The polyamic acid has a solid content of 8-25 wt% in the organic solvent.

[0012] The molar ratio of the carboxyl group in the polyamic acid to the amino group in the photosensitive modifier is 0.8-2.5.

[0013] The mass ratio of the crosslinking agent to the photosensitive modifier is 1:1.5-12.

[0014] The amount of photoinitiator added accounts for 0.5-12% of the total mass of the polyamic acid and the photosensitive modifier.

[0015] The viscosity of the slurry at 25°C is 200-400 mPa·s.

[0016] The method for preparing 3D printing polyimide slurry based on photothermal dual curing is characterized by comprising the following steps:

[0017] (1) Add the aromatic diamine containing the carboxyl functional group to the organic solvent and stir continuously under an inert gas atmosphere until it is completely dissolved;

[0018] (2) Add aromatic tetracarboxylic acid dianhydride to the solution in step (1) in batches and stir continuously to obtain a polyamic acid solution.

[0019] (3) Add the photosensitive modifier to the polyamic acid solution to prepare polyamide ammonium salt, and add a crosslinking agent;

[0020] (4) Add the photoinitiator to the solution and continue stirring to obtain the slurry.

[0021] In step (1), the inert gas is nitrogen or argon.

[0022] In step (2), the reaction temperature is 15-35℃ and the reaction time is 4-20 h.

[0023] In step (4), the stirring time after adding the photoinitiator is 0.5-5 h.

[0024] The application of the slurry in photothermal dual-curing 3D printing is characterized in that the application is used to manufacture high-temperature resistant and high-precision parts in the fields of aerospace, electronic devices or automobile manufacturing.

[0025] The photothermal dual-curing 3D printing includes the following steps: Degassing treatment: The slurry is placed in a degassing machine and degassed at a speed of 1500-3000 r / min for 2-5 min; Photocuring printing: 3D printing is performed using digital light processing technology, with the bottom layer exposure time being 5-30 s / layer and the normal exposure time being 10-30 s / layer, and each layer designed to be 30-80 μm thick; Washing and drying: The printed sample is washed with an organic solvent and then dried in air at room temperature for 12-48 h; Thermal imidization treatment: After drying, heat treatment is performed, with the temperature increased from room temperature to 250-350℃ at a heating rate of 2-10℃ / min and held for 5-30 min to achieve complete imidization.

[0026] The exposure wavelength for the photopolymerization printing is 365-405nm.

[0027] The thermal amidation treatment is carried out in an air atmosphere or an inert gas atmosphere.

[0028] The beneficial effects of this invention are: it integrates the flexibility of 3D printing in the molding of complex structures, and improves the mechanical strength and heat resistance of the sample; the three-point flexural strength of the prepared polyimide material is greater than 100MPa, and the thermal amidation shrinkage rate is 24.1%; at the same time, due to the heat treatment, the organic gel is endowed with a fully aromatic BTDA-DABA polyimide structure, which remains stable at a high temperature of 590℃. Attached Figure Description

[0029] Figure 1 Characterization of the thermal amidation surface morphology of PAA10(a), PAA15(b), and PAA20(c) printed parts.

[0030] Figure 2Mechanical properties of 3D printed polyimide (PI): (a) tensile strength curve, (b) elongation at break.

[0031] Figure 3 Characterization of tensile fracture sections: (a) pure PI section, (b) PI2 section containing PDMAEMA-b-PTMPTA. Detailed Implementation

[0032] This invention provides a 3D printing polyimide slurry based on photothermal dual curing. The raw materials for preparation include N-methylpyrrolidone (NMP), N,N-dimethylacetamide (DMAc), trimethylolpropane triacrylate (TMPTA), 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BDTA), 3,5-diaminobenzoic acid (DABA), dimethylaminoethyl methacrylate (DMAEMA), diphenyl (2,4,6-trimethylbenzoyl)phosphine oxide (TPO), and deionized water.

[0033] The reaction process of this patent is shown in the following formula:

[0034]

[0035] In some typical implementations, this patent includes the following technical solutions:

[0036] The preparation of 3D printing polyimide slurry based on photothermal dual curing includes the following steps:

[0037] (1) Add a certain amount of 3,5-diaminobenzoic acid (DABA) and organic solvent to a 250mL three-necked flask and stir continuously.

[0038] (2) After the DABA powder is completely dissolved, 3,3',4,4'-benzophenone tetracarboxylic acid dianhydride (BTDA) is added to the solution in batches and stirred continuously to obtain BTDA-DABA PAA solution.

[0039] (3) Polyamide ammonium was prepared by adding dimethylaminoethyl methacrylate (DMAEMA) to PAA solution.

[0040] Salt (PAAS) is added, and a crosslinking agent, trimethylolpropane triacrylate (TMPTA), is added to adjust the viscosity of the printing paste and the printing curing parameters.

[0041] (4) Add TPO to the solution and continue stirring to obtain the desired BTDA-DABA PAA 3D ​​printing slurry.

[0042] Furthermore, the organic solvent mentioned in step one is dimethylacetamide (DMAc).

[0043] Furthermore, the DABA and organic solvent described in step one are stirred under a nitrogen atmosphere.

[0044] Furthermore, the organic solvent content mentioned in step one is 80%.

[0045] Furthermore, in step two, the preferred molar ratio of DABA to BTDA is 1:1 to ensure the formation of a linear polymer structure of PAA.

[0046] Furthermore, after adding BTDA as described in step two, the reaction was continued at room temperature for 12 hours.

[0047] Furthermore, the solid content of the BTDA-DABA PAA solution prepared in step two is 20 wt%.

[0048] Furthermore, in step three, the mass of DMAEMA added follows a molar ratio of -COOH in PAA to -N(CH3)2 in DMAEMA of 2.

[0049] Furthermore, in step three, TMPTA:DMAEMA = 1:5 is added.

[0050] Furthermore, the viscosity of the printing paste described in step three is approximately 275 mPa·s.

[0051] Furthermore, the printing curing parameters described in step three are: 10 seconds of exposure per layer for the bottom layer, 20 seconds of normal exposure per layer, and a designed thickness of 50 μm for each layer.

[0052] Furthermore, the TPO added in step four accounts for 2.5% of the total mass of PAA and DMAEMA.

[0053] Furthermore, the stirring time after adding TPO as described in step four is two hours.

[0054] Example 1

[0055] A certain amount of 3,5-diaminobenzoic acid (DABA) and the organic solvent dimethylacetamide (DMAc) were added to a 250 mL three-necked flask and stirred continuously under a nitrogen atmosphere.

[0056] After the DABA powder was completely dissolved, 3,3',4,4'-benzophenone tetracarboxylic acid dianhydride (BTDA) was added to the solution in batches at a molar ratio of 1:1, and the total solid content was controlled at 10 wt%. The mixture was stirred continuously and the reaction was carried out at room temperature for 12 h to obtain a BTDA-DABA PAA solution.

[0057] Polyamide ammonium salt (PAAS) was prepared by adding dimethylaminoethyl methacrylate (DMAEMA) to PAA solution. The mass of DMAEMA added followed the molar ratio of -COOH in PAA to -N(CH3)2 in DMAEMA of 2. Trimethylolpropane triacrylate (TMPTA) (where TMPTA:DMAEMA = 1:5) was added to adjust the viscosity of the printing paste (approximately 275 mPa·s) and the printing curing parameters (10 seconds of exposure per layer for the bottom layer, 20 seconds of normal exposure per layer, and a designed thickness of 50 μm per layer).

[0058] Add TPO (2.5% of the total mass of PAA and DMAEMA) to the solution and continue stirring to obtain the desired BTDA-DABA PAA 3D ​​printing slurry, named PAA10.

[0059] After 3D printing under the same printing parameters, PI materials with different solid contents were prepared by sintering thermal amidation. The shrinkage rate was calculated by measuring the dimensions of the solid parts after photothermal curing.

[0060] The photothermal dual-curing 3D printing polyimide slurry was placed in a defoamer and degassed at 2000 rpm for 3 minutes before photocuring and 3D printing. The photocuring printing parameters were: bottom layer exposure time 20 s, bottom layer exposure time 15 s, and wavelength 365 nm. After photocuring, the resulting sample was washed with an organic solvent to remove uncured polymer solution. The sample was dried in air at room temperature for 24 hours. After drying, the polyamide underwent heat treatment: heating from room temperature to 300°C at a rate of 4°C / min and holding at that temperature for 10 minutes to achieve complete imidization.

[0061] The surface of the material was characterized by SEM using a desktop scanning electron microscope (FEG-SEM), and three-point bending resistance tests were performed on the material.

[0062] Example 2

[0063] A certain amount of 3,5-diaminobenzoic acid (DABA) and the organic solvent dimethylacetamide (DMAc) were added to a 250 mL three-necked flask and stirred continuously under a nitrogen atmosphere.

[0064] After the DABA powder has completely dissolved, add 3,3',4,4'-benzophenone tetracarboxylic acid dianhydride (BTDA).

[0065] The solution was added in batches to achieve a solid content of 15 wt%. The mixture was stirred continuously and the reaction was carried out at room temperature for 12 hours to obtain a BTDA-DABA PAA solution.

[0066] Polyamide ammonium salt (PAAS) was prepared by adding dimethylaminoethyl methacrylate (DMAEMA) to PAA solution. The mass of DMAEMA added followed the molar ratio of -COOH in PAA to -N(CH3)2 in DMAEMA of 2. Trimethylolpropane triacrylate (TMPTA) (where TMPTA:DMAEMA = 1:5) was added to adjust the viscosity of the printing paste (approximately 275 mPa·s) and the printing curing parameters (10 seconds of exposure per layer for the bottom layer, 20 seconds of normal exposure per layer, and a designed thickness of 50 μm per layer).

[0067] Add TPO (2.5% of the total mass of PAA and DMAEMA) to the solution and continue stirring to obtain the desired BTDA-DABA PAA 3D ​​printing slurry, named PAA15.

[0068] After 3D printing under the same printing parameters, PI materials with different solid contents were prepared by sintering thermal amidation. The shrinkage rate was calculated by measuring the dimensions of the solid parts after photothermal curing.

[0069] The photothermal dual-curing 3D printing polyimide slurry was placed in a defoamer and degassed at 2000 rpm for 3 minutes before photocuring and 3D printing. The photocuring printing parameters were: bottom layer exposure time 20 s, bottom layer exposure time 15 s, and wavelength 365 nm. After photocuring, the resulting sample was washed with an organic solvent to remove uncured polymer solution. The sample was dried in air at room temperature for 24 hours. After drying, the polyamide underwent heat treatment: heating from room temperature to 300°C at a rate of 4°C / min and holding at that temperature for 10 minutes to achieve complete imidization.

[0070] The surface of the material was characterized by SEM using a desktop scanning electron microscope (FEG-SEM), and three-point bending resistance tests were performed on the material.

[0071] Example 3

[0072] A certain amount of 3,5-diaminobenzoic acid (DABA) and the organic solvent dimethylacetamide (DMAc) were added to a 250 mL three-necked flask and stirred continuously under a nitrogen atmosphere.

[0073] After the DABA powder was completely dissolved, 3,3',4,4'-benzophenone tetracarboxylic acid dianhydride (BTDA) was added to the solution in batches to make the solid content 20 wt%. The mixture was stirred continuously and the reaction was carried out at room temperature for 12 h to obtain a BTDA-DABA PAA solution.

[0074] Polyamide ammonium salt (PAAS) was prepared by adding dimethylaminoethyl methacrylate (DMAEMA) to PAA solution. The mass of DMAEMA added followed the molar ratio of -COOH in PAA to -N(CH3)2 in DMAEMA of 2. Trimethylolpropane triacrylate (TMPTA) (where TMPTA:DMAEMA = 1:5) was added to adjust the viscosity of the printing paste (approximately 275 mPa·s) and the printing curing parameters (10 seconds of exposure per layer for the bottom layer, 20 seconds of normal exposure per layer, and a designed thickness of 50 μm per layer).

[0075] Add TPO (2.5% of the total mass of PAA and DMAEMA) to the solution and continue stirring to obtain the desired BTDA-DABA PAA 3D ​​printing slurry, named PAA20.

[0076] After 3D printing under the same printing parameters (10 seconds of exposure per layer for the bottom layer, 20 seconds of normal exposure per layer, and a designed thickness of 50 μm per layer), PI materials with different solid contents were prepared by sintering thermal amidation. The shrinkage rate was calculated by measuring the dimensions of the solid parts after photothermal curing.

[0077] The photothermal dual-curing 3D printing polyimide slurry was placed in a defoamer and degassed at 2000 rpm for 3 minutes before photocuring and 3D printing. The photocuring printing parameters were: bottom layer exposure time 20 s, bottom layer exposure time 15 s, and wavelength 365 nm. After photocuring, the resulting sample was washed with an organic solvent to remove uncured polymer solution. The sample was dried in air at room temperature for 24 hours. After drying, the polyamide underwent heat treatment: heating from room temperature to 300°C at a rate of 4°C / min and holding at that temperature for 10 minutes to achieve complete imidization.

[0078] The surface of the material was characterized by SEM using a desktop scanning electron microscope (FEG-SEM), and three-point bending resistance tests were performed on the material.

[0079] Statistical data from the implementation examples are shown in Table 1.

[0080] Table 1

[0081]

[0082] As can be seen from the above data, the material obtained by printing polyimide slurry based on photothermal dual curing of the present invention has the advantages of strong bending resistance and low shrinkage.

[0083] At the same time, by Figure 2 The images show the surface morphology of the thermally amidated parts printed in Examples 1-3. The comparison shows that the 3D printing polyimide slurry based on photothermal dual curing of the present invention can provide better thermal stability.

[0084] Example 4

[0085] A certain amount of 3,5-diaminobenzoic acid (DABA) and the organic solvent dimethylacetamide (DMAc) were added to a 250 mL three-necked flask and stirred continuously under a nitrogen atmosphere until completely dissolved. Subsequently, 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA) was added to the system in batches at an equimolar ratio (1:1) to DABA, and the reaction was carried out at room temperature for 12 h to prepare a polyamic acid (PAA) solution with a solid content controlled at 20 wt%.

[0086] Photocurable components, including dimethylaminoethyl methacrylate (DMAEMA) and trimethylolpropane triacrylate (TMPTA), were introduced into the PAA solution, with a mass ratio of TMPTA to DMAEMA of 1:5. By adjusting the molar ratio of DMAEMA to carboxyl groups (–COOH) in the PAA, the DMAEMA / COOH ratio was gradually increased from 0 to 1, denoted as 0, 0.25, 0.5, 0.75, and 1, respectively. The resulting samples were named PI0, PI1, PI2, PI3, and PI4. The slurry containing the photocurable components was 3D printed under the same printing parameters (10 s / layer for bottom layer exposure, 20 s / layer for normal exposure, and 50 μm thickness per layer). After solvent washing and drying at room temperature for 24 h, thermal imidization was performed: the temperature was increased to 300 °C at a rate of 4 °C / min and held for 10 min to obtain the final PI materials (PI1, PI2, PI3, and PI4). Pure PI material (PI0) was obtained by molding the slurry without the addition of photocuring components under the same heat treatment conditions.

[0087] It should be noted that the introduction of the photocurable component DMAEMA provides the system with a double-bonded structure that can participate in free radical polymerization, enabling the material to achieve rapid photocuring. However, the introduced flexible acrylate-containing side chains and cross-linked structures can disrupt the orderly stacking of the polyimide backbone to some extent, thus affecting the intrinsic mechanical properties of the material. Therefore, while ensuring good photocuring performance, the amount of photocurable component introduced needs to be strictly controlled to achieve a balance between molding performance and mechanical properties.

[0088] The subsequent heat treatment of sintered parts was investigated to explore the precision, material mechanical properties and cross-sectional morphology of photothermal dual-curing resin after photo- and thermal curing.

[0089] like Figure 2The mechanical properties of the photothermal dual-curing 3D printing PI material obtained in Example 4 are shown. Compared with pure PI (PI0), among the four samples with added photosensitive components, PI1 shows higher tensile strength and elongation at break, and its mechanical properties are comparable to those of pure PI (PI0). It can be seen that the introduction of a small amount of photocuring components can maintain the overall strength of PI and obtain photocuring molding capability.

[0090] like Figure 3 The image shows the tensile fracture cross-section characterization of the photothermal dual-curing 3D printed PI material obtained in Example 4 (Figure a is the cross-section of pure PI, and Figure b is the cross-section of PI2 containing PDMAEMA-b-PTMPTA). It can be confirmed that the tensile cross-section of pure PI has obvious pits and an uneven surface morphology. After introducing PDMAEMA into the PI molecular structure, the tensile fracture cross-section gradually becomes smooth and flat.

[0091] The above examples illustrate the present invention only to aid in understanding it and are not intended to limit the scope of the invention. Those skilled in the art can make various simple deductions, modifications, or substitutions based on the principles of this invention.

Claims

1. A 3D printing polyimide slurry based on photothermal dual curing, characterized in that, The raw material components of the slurry include: polyamic acid, a photosensitizing modifier, a crosslinking agent, a photoinitiator, and an organic solvent; wherein, the polyamic acid is polymerized from an aromatic tetracarboxylic acid dianhydride and an aromatic diamine containing a carboxyl functional group; the photosensitizing modifier is a (meth)acrylate compound containing unsaturated double bonds and amino groups, which is grafted onto the polyamic acid to form a polyamide ammonium salt; the crosslinking agent is a multifunctional (meth)acrylate crosslinking agent with a functionality of not less than 3; and the photoinitiator is an acylphosphine oxide ultraviolet photoinitiator.

2. The slurry according to claim 1, characterized in that, The aromatic tetracarboxylic dianhydride is selected from one or more of 3,3',4,4'-benzophenone tetracarboxylic dianhydride, pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 4,4'-oxobisphthalic anhydride, or 4,4'-(hexafluoroisopropene)phthalic anhydride; the aromatic diamine containing a carboxyl functional group is selected from one or more of 3,5-diaminobenzoic acid, 4-aminobenzoic acid-4'-aminophenyl ester, or 3,5-diaminophenylacetic acid.

3. The slurry according to claim 1, characterized in that, The photosensitive modifier is selected from one or more of dimethylaminoethyl methacrylate, dimethylaminopropyl methacrylate, dimethylaminoethyl acrylate, diethylaminoethyl methacrylate, or diethylaminopropyl methacrylate. The crosslinking agent is selected from one or more of trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, or trimethylolpropane trimethacrylate; The photoinitiator is selected from one or more of diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphine, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, or bis(2,6-dimethoxybenzoyl)-(2,4,4-trimethylpentyl)phosphine oxide.

4. The slurry according to claim 1, characterized in that, The polyamic acid has a solid content of 8-25 wt% in the organic solvent; the molar ratio between the aromatic tetracarboxylic dianhydride and the aromatic diamine containing a carboxyl functional group is in the range of (0.8-1.2):1; The molar ratio of the carboxyl group in the polyamic acid to the amino group in the photosensitive modifier is 0.8-2.5; the mass ratio of the crosslinking agent to the photosensitive modifier is 1:1.5-12; and the amount of the photoinitiator added accounts for 0.5-12% of the total mass of the polyamic acid and the photosensitive modifier.

5. A method for preparing a 3D printing polyimide slurry based on photothermal dual curing as described in any one of claims 1-4, characterized in that, Includes the following steps: (1) Add the aromatic diamine containing the carboxyl functional group to the organic solvent and stir continuously under an inert gas atmosphere until it is completely dissolved; (2) Add aromatic tetracarboxylic acid dianhydride to the solution in step (1) in batches and stir continuously to obtain a polyamic acid solution. (3) Add the photosensitive modifier to the polyamic acid solution to prepare polyamide ammonium salt, and add a crosslinking agent; (4) Add the photoinitiator to the solution and continue stirring to obtain the slurry.

6. The preparation method according to claim 5, characterized in that, In step (1), the inert gas is nitrogen or argon; In step (2), the reaction temperature is 15-35℃ and the reaction time is 4-20 h.

7. The preparation method according to claim 5, characterized in that, In step (4), the stirring time after adding the photoinitiator is 0.5-5 h.

8. An application of the slurry as described in any one of claims 1-4 in photothermal dual-curing 3D printing, characterized in that, The application is used to manufacture high-temperature resistant and high-precision components in the fields of aerospace, electronics, or automotive manufacturing.

9. The application according to claim 8, characterized in that, The photothermal dual-curing 3D printing includes the following steps: Degassing treatment: The slurry is placed in a degassing machine and degassed at a speed of 1500-3000 r / min for 2-5 min; Photocuring printing: 3D printing is performed using digital light processing technology, with the bottom layer exposure time being 5-30 s / layer and the normal exposure time being 10-30 s / layer, and each layer designed to be 30-80 μm thick; Washing and drying: The printed sample is washed with an organic solvent and then dried in air at room temperature for 12-48 h; Thermal imidization treatment: After drying, heat treatment is performed, with the temperature increased from room temperature to 250-350℃ at a heating rate of 2-10℃ / min and held for 5-30 min to achieve complete imidization.

10. The application according to claim 8, characterized in that, The exposure wavelength for the photopolymerization printing is 365-405nm; The thermal amidation treatment is carried out in an air atmosphere or an inert gas atmosphere.

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