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CN-121991394-A - Honeycomb enhanced in-situ foaming polyimide wave-absorbing foam composite material and preparation method thereof

CN121991394ACN 121991394 ACN121991394 ACN 121991394ACN-121991394-A

Abstract

The invention discloses a honeycomb enhanced in-situ foaming polyimide wave-absorbing foam composite material which is prepared by the steps of S1, adding aromatic dianhydride, aromatic diamine, triethanolamine, a foaming agent, dibutyl tin dilaurate, epoxy resin and a hydroxyl chain extender into an organic solvent, uniformly mixing, adding wave-absorbing functional particles, uniformly dispersing to obtain a component A, uniformly mixing the component A and the component B by taking polymethylene polyphenyl polyisocyanate as a component B to obtain a polyimide foaming precursor solution, S2, pouring the polyimide foaming precursor solution into a mold filled with a honeycomb core material, standing at room temperature for 2-6h to enable foam to grow in an in-situ limited area in pores of the honeycomb core material, then placing a semi-finished product into a vacuum condition for thermal imidization treatment, cooling and demolding to obtain a target product. In the method, the precursor solution is subjected to in-situ chemical foaming in the honeycomb pores by a one-step method, and the prepared composite material has excellent wave absorbing performance and mechanical property.

Inventors

  • WANG YUEYI
  • LI ZHUOYANG
  • LI NAN
  • XU HAIYAN
  • YAN DINGXIANG
  • LI ZHONGMING

Assignees

  • 四川大学

Dates

Publication Date
20260508
Application Date
20260211

Claims (10)

  1. 1. The preparation method of the honeycomb enhanced in-situ foaming polyimide wave-absorbing foam composite material is characterized by comprising the following two steps: S1, adding aromatic dianhydride, aromatic diamine, triethanolamine, a foaming agent, dibutyl tin dilaurate, epoxy resin and a hydroxyl chain extender into an organic solvent, uniformly mixing, adding wave-absorbing functional particles, and uniformly dispersing by ultrasonic to obtain a component A, taking polymethylene polyphenyl polyisocyanate as a component B, and mixing and stirring the component A and the component B for 20-60S to obtain a polyimide foaming precursor solution; s2, pouring the polyimide foaming precursor solution into a die provided with a honeycomb core material, standing at room temperature for 2-6h to enable foam to grow in situ in a limited area in pores of the honeycomb core material, then placing a semi-finished product under a vacuum condition for thermal imidization treatment, and cooling to obtain the target honeycomb enhanced type in situ foaming polyimide wave-absorbing foam composite material.
  2. 2. The method for preparing the honeycomb reinforced in-situ foaming polyimide wave-absorbing foam composite material according to claim 1, wherein the thermal imidization treatment is specifically to perform three-stage heating under vacuum conditions, wherein the temperature is firstly raised to 80-120 ℃ for heat preservation of 1-2 h, then raised to 150-180 ℃ for heat preservation of 1-2 h, and finally raised to 220-260 ℃ for heat preservation of 1-3 h.
  3. 3. The method for preparing the honeycomb reinforced in-situ foaming polyimide wave-absorbing foam composite material according to claim 1, wherein the honeycomb core material is selected from any one of phenolic honeycomb, aramid honeycomb, polypropylene honeycomb, polycarbonate honeycomb, polyetherimide honeycomb, polyphenylene sulfide honeycomb, metal honeycomb and ceramic honeycomb.
  4. 4. The method for preparing a honeycomb reinforced in-situ foaming polyimide wave-absorbing foam composite material according to claim 3, wherein the pore diameter of the honeycomb core material is 1.5-5.0 mm.
  5. 5. The method for preparing the honeycomb reinforced in-situ foaming polyimide wave-absorbing foam composite material according to claim 1, wherein the organic solvent is at least one selected from DMF, N-methylpyrrolidone, N-dimethylacetamide, dimethyl sulfoxide, gamma-butyrolactone, propylene carbonate, ethyl acetate, alcohol ketone and ethers.
  6. 6. The method for preparing the honeycomb reinforced in-situ foaming polyimide wave-absorbing foam composite material according to claim 1, wherein the aromatic dianhydride is pyromellitic dianhydride and the aromatic diamine is 4,4' -diaminodiphenylmethane.
  7. 7. The method for preparing the honeycomb reinforced in-situ foaming polyimide wave-absorbing foam composite material according to claim 1, wherein the foaming agent is any one of water, a bicarbonate and organic acid compound system, azodicarbonamide, di-p-toluenesulfonyl hydrazine and azodiisobutyronitrile.
  8. 8. The method for preparing the honeycomb reinforced in-situ foaming polyimide wave-absorbing foam composite material according to claim 1, wherein the wave-absorbing functional particles are selected from any one of CNT, graphene, carbonyl iron, polyaniline and barium ferrite.
  9. 9. The preparation method of the honeycomb reinforced in-situ foaming polyimide wave-absorbing foam composite material as claimed in claim 1, wherein the A component comprises the following components in parts by weight: 35-60 parts of aromatic dianhydride, 35-60 parts of aromatic diamine, 5-25 parts of epoxy resin, 1-8 parts of hydroxyl chain extender, 1-5 parts of foaming agent, 0.3-3 parts of wave-absorbing functional particles, 0.1-2 parts of triethanolamine and 0.01-0.3 part of dibutyl tin dilaurate.
  10. 10. A honeycomb reinforced in-situ foaming polyimide wave-absorbing foam composite material, which is characterized by being prepared by the preparation method of any one of claims 1-9.

Description

Honeycomb enhanced in-situ foaming polyimide wave-absorbing foam composite material and preparation method thereof Technical Field The invention relates to the technical field of wave-absorbing materials, in particular to a honeycomb reinforced in-situ foaming polyimide wave-absorbing foam composite material and a preparation method thereof. Background The wave-absorbing foam is considered as a structural wave-absorbing material with great potential due to its excellent electromagnetic wave absorption performance and ideal mechanical properties. At present, the research of the wave-absorbing foam structure is mainly focused on the aspects of light weight and flexible application, and the low compressive strength limits the long-term application of the wave-absorbing foam structure. Although the mechanical properties of the foam can be improved in terms of chemical regulation, process optimization and the like, the potential application of the foam as a direct bearing member in light and small space equipment is still difficult to meet. The defect of poor mechanical property of the high polymer foam material can be overcome by adopting a honeycomb reinforcing mode, meanwhile, the original integral foam can be separated by the honeycomb structure, and the periodic wave absorbing unit is constructed, so that the wave absorbing performance of the foam material can be further improved, and the cooperative improvement of the mechanical property and the wave absorbing performance is realized. For example, patent CN202211380907.6 discloses a preparation method of a honeycomb foam composite wave-absorbing material based on PMI foam, the PMI honeycomb foam composite wave-absorbing material is prepared by foaming, then carrying out surface functionalization treatment, cutting into slices, then immersing into wave-absorbing glue for multiple times, and finally pressing into honeycomb layer by layer, wherein the mechanical property and the wave-absorbing property of the obtained PMI foam honeycomb wave-absorbing material are improved to a certain extent. However, the process is complicated, conformal coating is difficult to achieve by hot pressing, and interface problems are easy to generate. Therefore, the technical problem existing at present is that the weak mechanical property of the wave-absorbing foam and the poor interface combination with the honeycomb are difficult to realize synergistic enhancement. Disclosure of Invention Aiming at the technical problems that the mechanical property of the wave-absorbing foam and the interface combination property of the honeycomb are difficult to realize synergistic enhancement, the invention provides a honeycomb enhanced in-situ foaming polyimide wave-absorbing foam composite material and a preparation method thereof. The invention provides a honeycomb reinforced in-situ foaming polyimide wave-absorbing foam composite material, which comprises the following two steps: S1, adding aromatic dianhydride, aromatic diamine, triethanolamine, a foaming agent, dibutyl tin dilaurate, epoxy resin and a hydroxyl chain extender into an organic solvent, uniformly mixing, adding wave-absorbing functional particles, uniformly dispersing by ultrasonic to obtain a component A, mixing the component A and the component B by taking polymethylene polyphenyl polyisocyanate (PAPI) as a component B, and stirring at a speed of 2000-3000 r/min for 20-60S to obtain a polyimide foaming precursor solution. In the component A, the weight parts of the components are as follows: 35-60 parts of aromatic dianhydride, 35-60 parts of aromatic diamine, 5-25 parts of epoxy resin, 1-8 parts of hydroxyl chain extender, 1-5 parts of foaming agent, 0.3-3 parts of wave-absorbing functional particles, 0.1-2 parts of triethanolamine and 0.01-0.3 part of dibutyl tin dilaurate. Wherein the organic solvent is at least one selected from N, N-Dimethylformamide (DMF), N-methylpyrrolidone (NMP), N-dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), gamma-butyrolactone (GBL), propylene carbonate, ethyl acetate, alcohol ketone (acetone, MEK), ether (THF, dioxane). The foaming agent is any one of water, a bicarbonate and organic acid compound system, azodicarbonamide (AC), di-p-toluenesulfonyl hydrazide (OBSH) and Azodiisobutyronitrile (AIBN). The wave-absorbing functional particles are selected from any one of CNT, graphene, carbonyl iron, polyaniline and barium ferrite. The aromatic dianhydride is preferably pyromellitic dianhydride (PMDA), and the aromatic diamine is preferably 4,4' -diaminodiphenylmethane (MT). The mass ratio of PMDA to MT is (97-102): 100. The hydroxyl chain extender is polyethylene glycol (PEG), preferably PEG with a number average molecular weight of 400-2000. S2, pouring the polyimide foaming precursor solution into a die provided with a honeycomb core material, standing at room temperature for 2-6h to enable foam to grow in situ in a limited area in pores of the honeycomb core material, then placing a