Search

CN-122010586-A - Mixed fiber felt reinforced carbon aerogel composite material and preparation method thereof

CN122010586ACN 122010586 ACN122010586 ACN 122010586ACN-122010586-A

Abstract

The invention relates to a mixed fiber felt reinforced carbon aerogel composite material and a preparation method thereof, wherein the composite material comprises a mixed fiber felt, the mixed fiber felt comprises a textile fiber cloth layer and a non-woven fiber felt layer, the textile fiber cloth layer and the non-woven fiber felt layer are alternately laminated along the thickness direction, carbon aerogel is filled in internal pores and interlayer gaps of the textile fiber cloth layer and the non-woven fiber felt layer, and the ratio of the thickness of the non-woven fiber felt layer to the length of fibers in the non-woven fiber felt layer is less than 1:2. The low thermal conductivity fiber is introduced, so that the low thermal conductivity fiber and the carbonization forming process of the carbon aerogel shrink synchronously, the compression strength of the material in the thickness direction is further effectively improved, and the problems of high thermal conductivity, high cost, low strength, difficulty in meeting the performance requirements under complex stress working conditions and difficulty in carrying out strength design in a targeted manner in the prior art are solved.

Inventors

  • HE YAO
  • LONG DONGHUI
  • NIU BO
  • LIU JIE
  • CAO YU

Assignees

  • 苏州实验室

Dates

Publication Date
20260512
Application Date
20260416

Claims (10)

  1. 1. A hybrid fiber mat reinforced carbon aerogel composite comprising: the mixed fiber felt comprises a woven fiber cloth layer and a non-woven fiber felt layer, wherein the woven fiber cloth layer and the non-woven fiber felt layer are alternately laminated along the thickness direction; Carbon aerogel filled in the internal pores and interlayer gaps of the woven fiber cloth layer and the non-woven fiber felt layer; The nonwoven fibrous mat layer thickness and the ratio of the fiber lengths in the nonwoven fibrous mat layer are <1:2.
  2. 2. The mixed fiber mat reinforced carbon aerogel composite of claim 1, wherein the ratio of the thickness of the nonwoven fiber mat layer to the length of the fibers in the nonwoven fiber mat layer is (1-3): 7.
  3. 3. The hybrid fiber mat reinforced carbon aerogel composite of claim 1, wherein the nonwoven fiber mat layer has a thickness of 10mm to 30mm.
  4. 4. The hybrid fiber mat reinforced carbon aerogel composite of claim 1, wherein the nonwoven fiber mat layer is made of low thermal conductivity fibers or a mixture of carbon fibers and one or more low thermal conductivity fibers, the low thermal conductivity fibers having a non-graphite crystalline structure, the precursor of the low thermal conductivity fibers having a greater linear shrinkage than the carbon fibers during carbonization.
  5. 5. The hybrid fiber mat reinforced carbon aerogel composite of claim 4, wherein the precursor of the low thermal conductivity fiber is one or more of viscose fiber, viscose pre-oxidized fiber, polyacrylonitrile pre-oxidized fiber, phenolic fiber.
  6. 6. The composite material of any one of claims 1-5, wherein the number of layers of woven fiber cloth and nonwoven fiber mat is greater than or equal to 5.
  7. 7. A method for preparing a hybrid fiber mat reinforced carbon aerogel composite, for preparing a hybrid fiber mat reinforced carbon aerogel composite as defined in any one of claims 1-6, comprising: S1, preparing a non-woven fiber felt layer prefabricated body singly by adopting a low heat conduction fiber precursor or preparing the non-woven fiber felt layer prefabricated body by adopting a low heat conduction fiber precursor and carbon fibers in a mixing way; s2, preparing a mixed fiber felt preform by layering, paving and knitting a non-woven fiber felt layer preform and a woven fiber cloth layer; s3, pre-soaking and curing the mixed fiber felt preform by adopting a first concentration carbon aerogel precursor solution to prepare a composite material intermediate; s4, impregnating and curing the composite material intermediate by using a second-concentration carbon aerogel precursor solution to prepare a composite material precursor, wherein the concentration of the carbon aerogel precursor in the second-concentration carbon aerogel precursor solution is higher than that of the first-concentration carbon aerogel precursor solution; And S5, carbonizing the composite precursor at high temperature to prepare a composite finished product with a mixed fiber felt reinforced structure.
  8. 8. The method for preparing the mixed fiber mat reinforced carbon aerogel composite material according to claim 7, wherein the content of the carbon aerogel precursor in the mixed liquid in the step S3 is 2-8wt%.
  9. 9. The method for preparing the mixed fiber mat reinforced carbon aerogel composite material according to claim 7, wherein the content of the carbon aerogel precursor in the mixed liquid in the step S4 is 20-55wt%.
  10. 10. The method for preparing the mixed fiber mat reinforced carbon aerogel composite material according to claim 7 or 9, wherein the impregnation pressure in the step S4 is 0.1mpa to 0.4mpa.

Description

Mixed fiber felt reinforced carbon aerogel composite material and preparation method thereof Technical Field The invention relates to the field of heat-proof and heat-insulating composite materials, in particular to a mixed fiber felt reinforced carbon aerogel composite material and a preparation method thereof. Background In the process that the aircraft enters the atmosphere at a high speed, the surface of the aircraft is rubbed with the atmosphere, an air flow can form a shock wave layer on the outer surface of the aircraft, and the high-speed air flow is compressed when flowing through the shock wave layer, so that a large amount of kinetic energy is converted into heat energy and is transferred to the surface of the aircraft, and a severe pneumatic heating environment is formed. The heat protection material is an important foundation stone for preventing heat from being transmitted inwards and guaranteeing the safety of the aircraft. The aerogel material is a porous material formed by stacking nano-scale particles in series, and the unique nano-network and nano-pore structure of the aerogel material can effectively inhibit gas-phase heat conduction, reduce solid-phase heat conduction and have important application in the field of heat protection. Among all aerogel materials, carbon aerogel has the highest thermal stability, can maintain basic mesoporous structure under the inert atmosphere of 2800 ℃ at the highest, and thus has excellent performance in the field of high-temperature heat insulation. The pure carbon aerogel has high brittleness and low mechanical strength, and the mechanical property of the pure carbon aerogel is improved by adopting a fiber reinforced mode. However, the conventional carbon fiber has the following drawbacks: The carbon fiber has high cost, and the adoption of the carbon fiber leads to the remarkable increase of the overall heat conductivity of the material, so that the practical application of the carbon aerogel composite material is limited; in addition, as the conventional carbon aerogel is mostly a homogeneous isotropic material, the material performance in all directions is uniform, the cracking direction is uncontrollable and difficult to expect, and the mechanical property of the composite material is difficult to improve by pertinence to the design of the composite material; And the common carbon fiber is stable at high temperature and is carbonized without shrinkage, and about 20% of line shrinkage exists in the high-temperature curing and carbonization processes of the carbon aerogel precursor (such as phenolic aldehyde), and the carbon aerogel precursor is not matched with the thermal shrinkage of the carbon fiber matrix, so that the improvement of compression resistance is greatly limited. There is an urgent need in the market for a carbon aerogel composite with low thermal conductivity, high strength, and low cost. Disclosure of Invention In view of the above analysis, the present invention aims to provide a method for preparing a mixed fiber mat reinforced carbon aerogel composite material, which is used for solving one of the problems of high thermal conductivity, high cost, low strength, etc. existing in the prior art. In one aspect, the present invention provides a hybrid fiber mat reinforced carbon aerogel composite comprising: the mixed fiber felt comprises a woven fiber cloth layer and a non-woven fiber felt layer, wherein the woven fiber cloth layer and the non-woven fiber felt layer are alternately laminated along the thickness direction; Carbon aerogel filled in the internal pores and interlayer gaps of the woven fiber cloth layer and the non-woven fiber felt layer; The nonwoven fibrous mat layer thickness and the ratio of the fiber lengths in the nonwoven fibrous mat layer are <1:2. Further, the ratio of the thickness of the nonwoven fibrous mat layer to the length of the fibers in the nonwoven fibrous mat layer satisfies (1-3): 7. Further, the thickness of the non-woven fibrous felt layer is 10 mm-30 mm. Further, the non-woven fiber felt layer is made of low thermal conductivity fibers or a mixture of carbon fibers and one or more low thermal conductivity fibers, the low thermal conductivity fibers have a non-graphite crystal structure, and the linear shrinkage rate of a precursor of the low thermal conductivity fibers in the carbonization forming process is larger than that of the carbon fibers. Further, the precursor of the low thermal conductivity fiber is one or more of viscose fiber, viscose fiber pre-oxidized fiber, polyacrylonitrile fiber pre-oxidized fiber and phenolic fiber. Further, the number of layers of the textile fiber cloth layer and the nonwoven fiber felt layer is more than or equal to 5. The preparation method of the mixed fiber mat reinforced carbon aerogel composite material is used for preparing the mixed fiber mat reinforced carbon aerogel composite material and comprises the following steps: S1, selecting a low-heat-conduct