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CN-122011301-A - Preparation method and application of photo-thermal dual-curing-based 3D printing polyimide slurry

CN122011301ACN 122011301 ACN122011301 ACN 122011301ACN-122011301-A

Abstract

The invention discloses preparation and application of 3D printing polyimide slurry based on photo-thermal dual curing, and relates to the field of high polymer chemical materials. The photo-sensitive coating is prepared from polyamide acid, a photo-sensitive modifier, a cross-linking agent and a photoinitiator. The photosensitive modifier is a (methyl) acrylic ester compound containing unsaturated double bond and amino, which is grafted on the polyamide acid to form polyamide ammonium salt, and the two-stage curing process of digital photo-treatment photo-curing and thermal amidation is adopted, the photo-curing realizes the rapid molding of complex structure, and the thermal amidation completes imidization reaction. The problems of high shrinkage rate and low molding precision of the traditional 3D printing polyimide are solved.

Inventors

  • CHEN XIANFU
  • TIAN XINYANG
  • Cao Qirui
  • HUANG CHUHAN
  • WANG WENYUAN
  • WU MENGJIA
  • QIU MINGHUI
  • FAN YIQUN

Assignees

  • 南京工业大学

Dates

Publication Date
20260512
Application Date
20260401

Claims (10)

  1. 1. A3D printing polyimide slurry based on photo-thermal dual curing is characterized in that the raw material components of the slurry comprise polyamide acid, a photosensitive modifier, a cross-linking agent, a photoinitiator and an organic solvent, wherein the polyamide acid is formed by polymerizing aromatic tetracarboxylic dianhydride and aromatic diamine containing carboxyl functional groups, the photosensitive modifier is a (methyl) acrylic ester compound containing unsaturated double bonds and amino groups, the (methyl) acrylic ester compound is grafted on the polyamide acid to form polyamide ammonium salt, the cross-linking agent is a polyfunctional (methyl) acrylic ester cross-linking agent, the functionality is not less than 3, and the photoinitiator is an acyl phosphine oxide ultraviolet initiator.
  2. 2. The slurry according to claim 1, wherein the aromatic tetracarboxylic dianhydride is one or more selected from 3,3', 4' -benzophenone tetracarboxylic dianhydride, pyromellitic dianhydride, 3', 4' -biphenyl tetracarboxylic dianhydride, 4' -oxydiphthalic anhydride and 4,4' - (hexafluoro-isopropenyl) diphthalic anhydride, and the aromatic diamine having carboxyl functional group is one or more selected from 3, 5-diaminobenzoic acid, 4-aminobenzoic acid-4 ' -aminophenyl ester and 3, 5-diaminophenylacetic acid.
  3. 3. The slurry according to claim 1, wherein the photosensitive modifier is selected from one or more of dimethylaminoethyl methacrylate, dimethylaminopropyl methacrylate, dimethylaminoethyl acrylate, diethylaminoethyl methacrylate, or diethylaminopropyl methacrylate; the cross-linking agent is selected from one or more of trimethylolpropane 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-trimethylbenzoyl phenylphosphonate, bis (2, 4, 6-trimethylbenzoyl) phenylphosphine oxide or bis (2, 6-dimethoxybenzoyl) - (2, 4-trimethylpentyl) phosphine oxide.
  4. 4. The slurry according to claim 1, wherein the polyamic acid has a solid content of 8 to 25 wt.% in the organic solvent, and the molar ratio between the aromatic tetracarboxylic dianhydride and the aromatic diamine having a carboxyl functional group is in the range of (0.8 to 1.2): 1; The molar ratio of carboxyl in the polyamic acid to amino 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 addition amount of the photoinitiator accounts for 0.5-12% of the total mass of the polyamic acid and the photosensitive modifier.
  5. 5. A method for preparing a photo-thermal dual cure based 3D printed polyimide paste according to any one of claims 1 to 4, comprising the steps of: (1) Adding aromatic diamine containing carboxyl functional groups into an organic solvent, and continuously stirring under an inert gas atmosphere until the aromatic diamine is completely dissolved; (2) Adding aromatic tetracarboxylic dianhydride into the solution in the step (1) in batches, and continuously stirring for reaction to obtain a polyamic acid solution; (3) Adding a photosensitive modifier into the polyamic acid solution to prepare a polyammonium salt, and adding a crosslinking agent; (4) And adding the photoinitiator into the solution, and continuing stirring to obtain the slurry.
  6. 6. The method according to claim 5, wherein in the step (1), the inert gas is nitrogen or argon; in the step (2), the reaction temperature is 15-35 ℃ and the reaction time is 4-20 h.
  7. 7. The process of claim 5, wherein in step (4), the agitation time after adding the photoinitiator is 0.5 to 5 h.
  8. 8. Use of the paste according to any of claims 1-4 in photo-thermal dual cure 3D printing for manufacturing high temperature and high precision components in aerospace, electronics or automotive manufacturing applications.
  9. 9. The method according to claim 8, wherein the photo-thermal dual-curing 3D printing comprises the steps of defoaming the slurry in a defoaming machine at a speed of 1500-3000r/min for 2-5min, photo-curing printing by using a digital photo-processing technology for 3D printing and forming, wherein the exposure time of the bottom layer is 5-30 s/layer, the normal exposure time is 10-30 s/layer, each layer is 30-80 μm, washing and drying, washing a sample obtained after printing by using an organic solvent, drying in the air at room temperature for 12-48h, and heat amidation treatment, drying, heating from room temperature to 250-350 ℃ at a heating rate of 2-10 ℃ per min, and preserving heat for 5-30min to realize complete imidization.
  10. 10. The use according to claim 8, wherein the photo-curing print has an exposure wavelength of 365-405nm; the thermal amidation treatment is performed under an air atmosphere or an inert gas atmosphere.

Description

Preparation method and application of photo-thermal dual-curing-based 3D printing polyimide slurry Technical Field The invention relates to the field of high polymer chemical materials, in particular to a preparation method and application of 3D printing polyimide slurry based on photo-thermal dual curing. Background Polyimide is a high-performance polymer composed of imide units, and is widely used in the fields of aerospace, electronics, automobiles, chemical industry and the like, 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 conventional processing conditions, more focusing polyimide fabrication into 2D forms such as thin films. With the development of 3D printing technology, researchers have enabled photosensitive precursors to crosslink under uv radiation to form 3D organogels by adding crosslinkable acrylates to the polyimide precursor backbone. Under the high-temperature heat treatment condition, the 3D printing material can be easily removed, and meanwhile, the precursor skeleton is completely and thermally amidated to be polyimide, so that the polyimide material can be spanned from a 2D structure to a 3D structure. The existing photo-curing precursor method mainly adopted by the 3D polyimide printing technology often faces the problem of high shrinkage rate after heat treatment, and the too high shrinkage rate leads to low molding precision and structural cracking, so that industrial application is limited. Therefore, developing a 3D printing polyimide material and process with low shrinkage and high molding accuracy becomes a key requirement for solving the bottleneck of the prior art. Disclosure of Invention The invention aims to overcome the defects of high shrinkage rate, low molding precision and easiness in cracking caused by solvents of the existing 3D printing polyimide, and provides a preparation method of 3D printing polyimide slurry based on photo-thermal dual-curing. The 3D printing polyimide slurry based on photo-thermal dual-curing comprises polyamide acid, a photosensitive modifier, a cross-linking agent, a photoinitiator and an organic solvent, wherein the polyamide acid is formed by polymerizing aromatic tetracarboxylic dianhydride and aromatic diamine containing carboxyl functional groups, the photosensitive modifier is a (methyl) acrylic ester compound containing unsaturated double bonds and amino groups, the (methyl) acrylic ester compound is grafted on the polyamide acid to form polyamide ammonium salt, the cross-linking agent is a polyfunctional (methyl) acrylic ester cross-linking agent, the functionality is not less than 3, and the photoinitiator is an acyl phosphine oxide ultraviolet initiator. The aromatic tetracarboxylic dianhydride is selected from one or more of 3,3', 4' -benzophenone tetracarboxylic dianhydride, pyromellitic dianhydride, 3',4' -biphenyl tetracarboxylic dianhydride, 4 '-oxydiphthalic anhydride or 4,4' - (hexafluoro-isopropenyl) diphthalic anhydride. The aromatic diamine containing carboxyl functional groups is selected from one or more of 3, 5-diaminobenzoic acid, 4-aminobenzoic acid-4' -aminophenyl ester or 3, 5-diaminophenylacetic acid. The photosensitive modifier is selected from dimethylaminoethyl methacrylate dimethylaminopropyl methacrylate dimethylaminoethyl acrylate diethylaminoethyl methacrylate or methacrylic acid one or more of diethylaminopropyl acid esters. The cross-linking agent is selected from one or more of trimethylolpropane 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-trimethylbenzoyl phenylphosphonate, bis (2, 4, 6-trimethylbenzoyl) phenylphosphine oxide or bis (2, 6-dimethoxybenzoyl) - (2, 4-trimethylpentyl) phosphine oxide. The organic solvent is one or more polar aprotic solvents selected from N, N-dimethylacetamide, N-methylpyrrolidone, N-dimethylformamide or dimethyl sulfoxide. The solid content of the polyamic acid in the organic solvent is 8 to 25wt%. The molar ratio of carboxyl groups in the polyamic acid to amino groups in the photosensitive modifier is 0.8-2.5. The mass ratio of the cross-linking agent to the photosensitive modifier is 1:1.5-12. The addition amount of the photoinitiator accounts for 0.5-12% of the total mass of the polyamic acid and the photosensitive modifier. The viscosity of the slurry is 200-400 mPa.s at 25 ℃. The preparation method of the photo-thermal dual-curing-based 3D printing polyimide slurry is characterized by comprising the following steps of: (1) Adding aromatic diamine containing carboxyl functional groups into an organic solvent, and continuously stirring under an inert gas atmosphere until the aromatic diamine is completely dissolved; (2) Adding aromatic te