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CN-122011495-A - Preparation method of interpenetrating network phenolic aerogel and carbon aerogel and electromagnetic shielding application thereof

CN122011495ACN 122011495 ACN122011495 ACN 122011495ACN-122011495-A

Abstract

The invention discloses a preparation method of interpenetrating network phenolic aerogel and carbon aerogel and electromagnetic shielding application thereof, wherein the interpenetrating network phenolic aerogel takes boric acid modified phenolic resin and self-matched zirconium solution as precursors, proper amount of metal ions are introduced to be stably chelated with an organic structure, and high integration of the metal ions in an interpenetrating network system is realized through sol-gel and normal pressure drying technology, so that the key problem that the structure of the traditional organic aerogel and part of organic-inorganic composite aerogel is easy to collapse and unstably at ultrahigh temperature is solved. The interpenetrating network phenolic aerogel has extremely low heat conductivity and extremely high carbon residue rate at high temperature, also has excellent mechanical strength and good processability, has the advantages of economical cost in the preparation process and simple and convenient operation, can remarkably shorten the production period, and has excellent large-scale production prospect. Meanwhile, the carbon aerogel obtained based on the aerogel heat treatment has the characteristics of strong electromagnetic shielding capability and high compression ratio modulus.

Inventors

  • ZHONG ZHENGXIANG
  • Niu Donghan
  • XU HUIFANG
  • LIU JIANGFENG
  • Cao Rongyao
  • LIU LI
  • HUANG YUDONG

Assignees

  • 哈尔滨工业大学

Dates

Publication Date
20260512
Application Date
20260324

Claims (10)

  1. 1. The preparation method of the interpenetrating network phenolic aerogel is characterized by comprising the following steps of: Step 1, mixing boron modified phenolic resin, zirconium solution and metal ion ligand, adding boron modified phenolic resin curing agent and zirconium solution curing agent, uniformly mixing, and vacuumizing to obtain interpenetrating network phenolic resin precursor mixed solution, wherein the mass of the metal ion ligand is 0.01-10% of the mass of the boron modified phenolic resin, the mass of the boron modified phenolic resin curing agent is 0.01-10% of the mass of the boron modified phenolic resin, the mass of the zirconium solution is 40-60% of the mass of the boron modified phenolic resin, and the molar ratio of the zirconium solution curing agent to a zirconium source is 3-10; Step 2, carrying out sol-gel reaction on the interpenetrating network phenolic resin precursor mixed solution to obtain wet gel, wherein the temperature of the sol-gel reaction is 60-180 ℃, the environment is a high-pressure closed environment, and the time is 12-72 h; And step 3, drying the wet gel at normal pressure to obtain the interpenetrating network phenolic aerogel.
  2. 2. The method for preparing the interpenetrating network phenolic aerogel according to claim 1, characterized in that the preparation steps of the boron modified phenolic resin are as follows: Uniformly mixing a base catalyst and a phenolic compound, adding an aldehyde compound, and reacting for 1-4 hours at 60-80 ℃ to obtain thermosetting phenolic resin, wherein the base catalyst comprises one or more of potassium hydroxide, sodium hydroxide, barium hydroxide, ammonia water, triethylamine and hexamethylenetetramine, the aldehyde compound comprises one of formaldehyde, acetaldehyde and furfural, the phenolic compound is one of phenol, cresol, xylenol and resorcinol, and the molar ratio of aldehyde groups to phenol groups in the phenol is 1:1.5-1:2.0; Dissolving boric acid in a solvent, adding the solvent into thermosetting phenolic resin, and reacting for 2-6 hours at 60-80 ℃ to obtain boron modified phenolic resin, wherein the boric acid accounts for 3-10% of the mass of the thermosetting phenolic resin, the solvent is one or more of methanol, ethanol, isopropanol, butanol and n-propanol, the boric acid accounts for 3-10% of the mass of the solvent, and the solid content of the boron modified phenolic resin is 30-60%.
  3. 3. The preparation method of the interpenetrating network phenolic aerogel according to claim 1, wherein the zirconium solution is obtained by stirring and dissolving a zirconium source and a solvent according to a solid content ratio, wherein the zirconium source is one or more of zirconium tetraisopropoxide, zirconium tetra-n-propoxide, zirconium tetra-ethanol, zirconium tetra-methoxide, zirconium oxychloride, zirconium nitrate, zirconium acetylacetonate and zirconium glycol, and the solvent is one or more of methanol, ethanol, n-propanol, isopropanol, methyl ether and diethyl ether, and the solid content is 10-40%.
  4. 4. The preparation method of the interpenetrating network phenolic aerogel according to claim 1, wherein the boron modified phenolic resin curing agent is protonic acid and comprises one or more of phosphoric acid, hydrochloric acid, sulfuric acid, nitric acid, oxalic acid, p-toluenesulfonic acid, xylenesulfonic acid, ethyl sulfate and sulfonyl chloride, the zirconium solution curing agent is one or more of p-toluenesulfonic acid, benzenesulfonic acid, methanesulfonic acid, malic acid, citric acid, oxalic acid, phosphoric acid, boric acid and phthalic anhydride, and the metal ion ligand is one or more of tantalum methoxide, tantalum ethoxide, tantalum n-propoxide, tantalum isopropoxide, titanium methoxide, titanium ethoxide, titanium n-propoxide, titanium isopropoxide, niobium methoxide, niobium ethoxide, niobium n-propoxide, niobium isopropoxide, hafnium methoxide, hafnium ethoxide, hafnium n-propoxide and hafnium isopropoxide.
  5. 5. The preparation method of the interpenetrating network phenolic aerogel according to claim 1 is characterized in that the mixing temperature is 20-30 ℃, the mixing time is 5-30 min, the mixing is performed under stirring conditions, the vacuumizing time is 10-30 min, the normal-pressure drying comprises room-temperature pre-drying and oven drying, the room-temperature pre-drying time is 2-12 h, the oven drying time is 6-24 h, and the temperature is 50-80 ℃.
  6. 6. An interpenetrating network phenolic aerogel prepared by the method of any one of claims 1-5.
  7. 7. A method for preparing a carbon aerogel, characterized in that the carbon aerogel is obtained by volume ablation of an interpenetrating network phenolic aerogel obtained by the method according to any one of claims 1 to 5.
  8. 8. The method for preparing the carbon aerogel according to claim 7, wherein the volume ablation is performed in a protective gas atmosphere and a closed environment, the temperature of the volume ablation is 600-1600 ℃, and the heat preservation time is 0.5-1 h.
  9. 9. A carbon aerogel prepared by the method of any of claims 7-8.
  10. 10. Use of the carbon aerogel prepared by the method of any of claims 7-8 in the field of electromagnetic shielding.

Description

Preparation method of interpenetrating network phenolic aerogel and carbon aerogel and electromagnetic shielding application thereof Technical Field The invention belongs to the technical field of thermal protection, and relates to a preparation method of interpenetrating network phenolic aerogel and carbon aerogel and electromagnetic shielding application thereof. Background The aerogel is a material with ultra-low density, non-static and nano-porous, and the phenolic aerogel is widely applied to the fields of thermal protection of military industry, aerospace and the like due to the characteristics of excellent heat preservation and insulation performance, excellent ablation resistance and low sintering shrinkage rate. However, with the deep search of the field, the requirements for quality, performance and the like of the heat-proof equipment are higher. Currently, the synthesis of phenolic aerogels is mainly achieved by a thermoplastic phenolic resin or resorcinol-formaldehyde resin system, via a sol-gel process and subsequent drying techniques. The process is generally long in time consumption and generally takes 2 to 10 days, and has complex flow and high requirements on equipment and conditions. In comparison, thermosetting phenolic resins (such as sodium phenolic, barium phenolic or boron phenolic) exhibit superior thermal stability and ablation resistance, providing potential for their use in the field of high temperature protection. In addition, phenolic aerogel has important application prospect in the field of aerospace thermal protection as a light heat insulation material, but the traditional system has obvious limitations that firstly, the traditional phenolic aerogel has poor mechanical property and is difficult to bear a high-stress environment, secondly, the traditional phenolic aerogel has insufficient temperature resistance limit (usually less than 1200 ℃) and a framework is easy to oxidize and decompose at high temperature to cause structural collapse, thirdly, the preparation process depends on supercritical drying (such as CO 2 supercritical drying), and has complex flow, long period (up to several days) and high cost, and fourthly, the traditional modification scheme (such as silicon and boron single doping) can improve part of performances, but often sacrifice density or heat insulation and has missing high-temperature electromagnetic shielding function. In recent years, researchers have attempted to solve these problems by multiple doping (e.g., silicon boron zirconium, POSS) and interpenetrating network structure design, but still face challenges such as phase separation, complex process, or single function. Under the background, developing an integrated aerogel which can resist ultrahigh temperature, has strong mechanical strength and toughness, is efficient in heat insulation and has a high-temperature electromagnetic shielding function becomes a key direction for breaking through the bottleneck of the prior art. Thus, the preparation of multifunctional phenolic aerogels integrated with interpenetrating networks is a significant challenge. Disclosure of Invention The invention provides a preparation method and electromagnetic shielding application of interpenetrating network phenolic aerogel and carbon aerogel, wherein the interpenetrating network phenolic aerogel not only has extremely low heat conductivity and extremely high carbon residue rate at high temperature, but also has excellent mechanical strength and good processability, and the preparation process is economic in cost and simple and convenient to operate, can obviously shorten the production period, and has excellent large-scale production prospect. Meanwhile, the carbon aerogel obtained based on the aerogel heat treatment has the characteristics of strong electromagnetic shielding capability and high compression ratio modulus. The invention aims at realizing the following technical scheme: The preparation method of the interpenetrating network phenolic aerogel takes boric acid modified phenolic resin and self-matched zirconium solution as precursors, introduces a proper amount of metal ions to be stably chelated with an organic structure, realizes the high integration of the metal ions in an interpenetrating network system through sol-gel and normal pressure drying technology, and specifically comprises the following steps: Step 1, mixing boron modified phenolic resin, zirconium solution and metal ion ligand, adding boron modified phenolic resin curing agent and zirconium solution curing agent, uniformly mixing, and vacuumizing to obtain interpenetrating network phenolic resin precursor mixed solution, wherein: The preparation method comprises the steps of uniformly mixing a base catalyst and a phenolic compound, adding an aldehyde compound, reacting for 1-4 hours at 60-80 ℃ to obtain thermosetting phenolic resin, wherein the base catalyst comprises one or more of potassium hydroxide, sodium hydroxide, barium hydro