CN-121991400-A - Zirconium-silicon ceramic precursor modified phenolic aerogel and preparation method thereof

CN121991400ACN 121991400 ACN121991400 ACN 121991400ACN-121991400-A

Abstract

The invention discloses a zirconium silicon ceramic precursor modified phenolic aerogel and a preparation method thereof, comprising (1) preparing a zirconium silicon ceramic precursor; the preparation method comprises the steps of (1) mixing a zirconium-silicon ceramic precursor with phenolic resin, a solvent and a curing agent to prepare a mixed solution, then performing closed heating to perform gel reaction to prepare zirconium-silicon ceramic precursor modified phenolic wet gel, and (3) removing a liquid phase in the zirconium-silicon ceramic precursor modified phenolic wet gel to obtain the zirconium-silicon ceramic precursor modified phenolic aerogel. The zirconium-silicon ceramic precursor is connected into a framework of the phenolic aerogel in a molecular hybridization mode and can be vitrified at high temperature to form a protective layer, so that the problem that ceramic components are difficult to effectively introduce into a phenolic resin system is solved, and the high-temperature oxidation resistance of the phenolic aerogel is remarkably improved.

Inventors

YANG YIMING
LI YAFEI
LI HAO
ZHANG YONGQING
CHEN FENGHUA
HAN WEIJIAN
ZHAO TONG

Assignees

中国科学院化学研究所

Dates

Publication Date: 20260508
Application Date: 20241101

Claims (10)

1. The preparation method of the zirconium silicon ceramic precursor modified phenolic aerogel is characterized by comprising the following steps of: (1) Preparing a zirconium silicon ceramic precursor; (2) Mixing a zirconium silicon ceramic precursor with phenolic resin, a solvent and a curing agent to prepare a mixed solution, and then performing closed heating to perform a gel reaction to prepare a zirconium silicon ceramic precursor modified phenolic wet gel; (3) And removing the liquid phase in the zirconium-silicon ceramic precursor modified phenolic wet gel to obtain the zirconium-silicon ceramic precursor modified phenolic aerogel.
2. The method for preparing a zirconium silicon ceramic precursor modified phenolic aerogel of claim 1, wherein in step (1), the method for preparing a zirconium silicon ceramic precursor comprises: and dissolving a zirconium source, a silicon source and a ligand in a solvent for reaction to prepare the zirconium-silicon ceramic precursor.
3. The method for preparing the zirconium silicon ceramic precursor modified phenolic aerogel according to claim 2, wherein the content of zirconium element in the prepared zirconium silicon ceramic precursor is 10-35wt%; Preferably, the zirconium source is at least one selected from propyl zirconate, zirconium oxychloride, tetrabutyl zirconate and isopropyl zirconate.
4. The method for preparing the zirconium silicon ceramic precursor modified phenolic aerogel according to claim 2, wherein the molar ratio of zirconium element to silicon element in the prepared zirconium silicon ceramic precursor is 1 (0-3), and the content of silicon element is not 0; Preferably, in the silicon ceramic precursor, the molar ratio of the zirconium element to the silicon element is 1 (2.5-3); Preferably, the silicon source is at least one selected from methyltrimethoxysilane, dimethyldimethoxysilane, diphenyldimethoxysilane, methylphenyldimethoxysilane and phenyltrimethoxysilane.
5. The method for preparing a zirconium silicon ceramic precursor modified phenolic aerogel according to claim 2, wherein the ligand can form a coordination compound with zirconium metal ions and stably coexist with phenolic resin; preferably, the ligand is at least one selected from salicyl alcohol, acetylacetone, benzoylacetone, ethylenediamine, dimethylamine and acetic acid.
6. The method for preparing a modified phenolic aerogel of a zirconium silicon ceramic precursor according to any one of claims 1 to 5, wherein in the step (2), the mass ratio of the zirconium silicon ceramic precursor to the phenolic resin is (5 to 90): 90; Preferably, the mass ratio of the zirconium silicon ceramic precursor to the phenolic resin is (45-75): 90.
7. The method for preparing zirconium-silicon ceramic precursor modified phenolic aerogel according to any one of claims 1 to 5, wherein in the step (2), the content of zirconium element in the prepared mixed solution is 2 to 5wt%; Preferably, the content of the zirconium element in the prepared mixed solution is 2.5-3.5wt%.
8. The method for preparing a zirconium silicate ceramic precursor modified phenolic aerogel according to any one of claims 1 to 5, wherein in the step (2), the solvent is at least one selected from isopropanol, ethylene glycol monomethyl ether, ethylene glycol, ethanol and ethylene glycol diethyl ether; preferably, the solvent is mixed liquid of isopropanol, ethanol and ethylene glycol monomethyl ether or mixed liquid of isopropanol, ethylene glycol monomethyl ether and ethylene glycol; preferably, the curing agent is at least one selected from hexamethylenetetramine, formaldehyde, paraformaldehyde and p-toluenesulfonic acid.
9. The method for preparing a zirconium silicon ceramic precursor modified phenolic aerogel according to any one of claims 1 to 5, wherein in the step (2), the gel reaction is carried out in a closed reactor at a reaction temperature of 70 to 110 ℃ for a reaction time period of 12 to 48 hours; Preferably, the reaction temperature is 100-110 ℃.
10. The zirconium-silicon ceramic precursor modified phenolic aerogel is characterized in that the zirconium element content in the zirconium-silicon ceramic precursor modified phenolic aerogel is 6-15wt% and the silicon element content is 10-15wt%; preferably, the residual weight of the zirconium silicon ceramic precursor modified phenolic resin aerogel is more than or equal to 38% after being ablated for 30 minutes in a muffle furnace at 1400 ℃ and more than or equal to 50% after being ablated for 30 minutes in the muffle furnace at 1000 ℃; Preferably, the zirconium-silicon ceramic precursor modified phenolic aerogel has a rich mesoporous structure, zirconium elements and silicon elements are uniformly distributed in an aerogel carbon skeleton, and the zirconium-silicon ceramic precursor modified phenolic aerogel is mesoporous after ablation, and has an average pore diameter of 100-120nm and 100nm; preferably, the zirconium silicon ceramic precursor modified phenolic aerogel is prepared by adopting the preparation method as claimed in any one of claims 1 to 9.

Description

Zirconium-silicon ceramic precursor modified phenolic aerogel and preparation method thereof Technical Field The invention belongs to the technical field of aerogel materials and the field of phenolic resin materials, and particularly relates to zirconium-silicon ceramic precursor modified phenolic aerogel and a preparation method thereof. Background Aerogel is a porous material having a three-dimensional continuous network formed by stacking nanoparticles with each other, and has been attracting attention of scientists in various fields due to its characteristics of low density, high porosity, high specific surface area, low thermal conductivity, etc. With the rapid development of aerogel, various high-performance aerogel materials are continuously appeared, and have shown attractive application prospects in the fields of environmental protection, energy storage and conversion, biomedical treatment and the like. Phenolic resin is used as a traditional thermosetting resin material, the raw material cost is low, the preparation is easy, and the aerogel prepared from the phenolic resin has the characteristics of excellent thermal and chemical stability, heat insulation, fire resistance, high carbon residue rate and the like, so that the phenolic resin aerogel has good application prospect in high-temperature heat insulation materials. However, due to poor oxidation resistance of phenolic aerogel, the carbon residue rate is low in a high-temperature aerobic ablation environment, and the application of the phenolic aerogel is restricted. In order to improve the oxidation resistance of phenolic aerogels, it is currently common practice to modify the phenolic aerogels by introducing inorganic components. The organosilicon modified phenolic aerogel is a double-network modified phenolic aerogel obtained by directly copolymerizing organosilicon resin and phenolic. The organosilicon can be converted into silicon dioxide ceramic at high temperature to form an antioxidation layer to prevent the oxygen-containing heat flow from further eroding the carbon skeleton of the phenolic aerogel. However, silica is difficult to withstand high temperature environments of 1200 ℃ or more, and in order to further improve the temperature resistance level, elements having a higher temperature resistance level such as zirconium are required to be introduced. The zirconium inorganic component is modified mainly by adding inorganic powder such as zirconium carbide, zirconium boride and the like. However, the method increases the density of the aerogel due to the introduction of the powder, and the process is complex. In addition, the powder is easy to generate phenomena of sedimentation, aggregation and the like in the aerogel preparation process, and can generate large-scale phase separation with phenolic resin, so that the material is invalid. Therefore, by starting from the composition of the aerogel, the high-temperature-resistant and oxidation-resistant ceramic component is introduced into the aerogel in a molecular-level hybridization mode, and the phenolic aerogel with simple preparation process and excellent performance is developed to realize the high-temperature oxidation resistance of the phenolic aerogel, so that the phenolic aerogel has important application value. It has been reported that zirconium silicon element is introduced into phenolic resin by adding zirconium source such as propyl zirconate, butyl zirconate, methyltrimethoxysilane and the like and silicon source, but because of high reactivity and hydrolysis rate of zirconium source such as propyl zirconate, the reaction is intense and unstable at high concentration, so that it is difficult to obtain phenolic resin aerogel with high zirconium content. In addition, because the zirconium source hydrolysis polymerization and phenolic resin polymerization modes are different, the zirconium source hydrolysis polymerization and phenolic resin polymerization modes are difficult to form uniform copolymerization with phenolic aldehyde, the overall reaction rate is uncontrollable, and large-scale phase separation can be generated. It is currently difficult to control how the three components of zirconium, silicon and phenolic resin are homogeneously copolymerized in the sol-gel process without phase separation. For example, chinese patent application No. 202310792650.3 discloses a silicon-zirconium chemically modified phenolic aerogel and a preparation method thereof, wherein the method uses linear phenolic aldehyde as a main raw material, uses hexamethylenetetramine as a catalyst, uses absolute ethyl alcohol as a reaction solvent, and obtains silicon-zirconium double-element atomic-level uniformly modified anti-ablation phenolic aerogel through adding proper organic zirconium and silane, heating, curing and normal-pressure drying. In the technical scheme, three components of zirconium element, silicon element and phenolic resin are easy to generate phase separation in the g