A phenolic / zirconium aluminum phosphate-based dual-network high-temperature resistant foam and its preparation method

Abstract

This invention discloses a phenolic / zirconium aluminum phosphate-based dual-network high-temperature resistant foam and its preparation method. The foam comprises a zirconium aluminum phosphate matrix, a water-soluble phenolic prepolymer, a high-temperature resistant filler, a foaming agent, a curing agent, and a foam stabilizer. This invention constructs an organic-inorganic dual-network structure through the co-construction of an organic-inorganic network by the water-soluble phenolic prepolymer and zirconium aluminum phosphate resin. The water-soluble phenolic prepolymer acts as the organic network, significantly improving the material's bonding strength, toughness, and compressive strength. The zirconium aluminum phosphate resin forms a rigid inorganic network, endowing the material with excellent ultra-high temperature resistance. By controlling the foaming rate through the synergistic reaction of foaming and curing, a porous foam structure with uniform pore size and stable structure is prepared. This material combines lightweight, ultra-high temperature resistance, and excellent thermal insulation properties, enabling adaptive filling of complex-sized gaps and rapid on-site foaming molding. It is suitable for applications such as thermal protection for aerospace vehicles, thermal insulation layers for rocket engines, and high-temperature sealing.

Description

Technical Field

[0001] This invention belongs to the technical field of high-temperature resistant adhesives and thermal protection materials, and relates to a high-temperature resistant foam adhesive and its preparation method, specifically to a foam adhesive based on a dual-network structure of water-soluble phenolic prepolymer and zirconium aluminum phosphate resin and its preparation method. Background Technology

[0002] With the rapid development of hypersonic vehicles, reusable launch vehicles, and deep space exploration technologies, the surfaces and internal structures of these vehicles face extreme aerodynamic heating environments during service, with local temperatures exceeding 1500℃. This places stringent requirements on the temperature resistance, structural integrity, and ease of construction of thermal protection materials. While traditional organic foam materials (such as polyurethane and phenolic foam) possess good thermal insulation and construction properties, they are prone to pyrolysis, carbonization, and even combustion at high temperatures, making them unsuitable for use in long-term, high-heat-flux-density environments. Inorganic phosphate materials, due to their excellent thermal stability and non-flammability, have gradually become a research hotspot in the field of high-temperature protection.

[0003] Furthermore, the assembly gaps between aircraft structural components and the thermal expansion gaps between heat-resistant tiles are the most vulnerable links in the thermal protection system. Traditional inorganic adhesives are difficult to balance large-size gaps with rapid construction, mainly due to: (1) large curing shrinkage and easy cracking; (2) high density, which cannot meet the requirements for lightweighting. Therefore, developing a material that has the ultra-high temperature stability of phosphate, the excellent bonding performance and toughness of phenolic resin, and can fill large-size gaps through rapid foaming is the key to ensuring the flight safety of advanced spacecraft. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a phenolic / zirconium aluminum phosphate-based dual-network high-temperature resistant foam and its preparation method. This invention constructs an organic-inorganic dual-network structure using a water-soluble phenolic prepolymer and zirconium aluminum phosphate resin. The water-soluble phenolic prepolymer acts as the organic network, significantly improving the material's bonding strength, toughness, and compressive strength. The zirconium aluminum phosphate resin forms a rigid inorganic network, endowing the material with excellent ultra-high temperature resistance (up to 1500℃). By controlling the foaming rate through a synergistic reaction of foaming and curing, a porous foam structure with uniform pore size and stable structure is prepared. The minimum density after foaming can reach 0.25 g / cm³, the thermal conductivity is 0.040~0.044 W / m·K, and the compressive strength is 3.80 MPa. This material combines lightweight, ultra-high temperature resistance, and excellent thermal insulation properties, enabling adaptive filling of complex-sized gaps and rapid on-site foaming molding. It is suitable for applications such as thermal protection for aerospace vehicles, thermal insulation layers for rocket engines, and high-temperature sealing.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A phenolic / zirconium aluminum phosphate-based dual-network high-temperature resistant foam comprises 40-60 parts by weight of a zirconium aluminum phosphate matrix, 10-30 parts by weight of a water-soluble phenolic prepolymer, 20-50 parts by weight of a high-temperature resistant filler, 1-10 parts by weight of a foaming agent, 1-10 parts by weight of a curing agent, and 0.1-3 parts by weight of a foam stabilizer. The foaming agent and curing agent synergistically regulate the foaming rate, enabling rapid foaming and molding at room temperature to form an organic-inorganic dual-network structure that maintains structural stability at high temperatures.

[0007] The zirconium aluminum phosphate matrix is ​​prepared from the following raw materials by weight: 100 parts phosphoric acid, 10-30 parts aluminum hydroxide, 5-20 parts zirconium oxychloride, 1-10 parts citric acid, and 20-50 parts deionized water. The specific preparation steps are as follows: Weigh the phosphoric acid and add the deionized water to a three-necked flask. Stir the mixture magnetically at a constant temperature of 80-100°C until it is fully diluted. Add aluminum hydroxide and stir magnetically at a constant temperature until it is completely dissolved. Add zirconium oxychloride and citric acid and react for 1-3 hours to obtain the zirconium aluminum phosphate matrix.

[0008] The high-temperature resistant filler is selected from one or more of alumina, silicon dioxide, silicon carbide, boron nitride, quartz powder, zirconium oxide, zirconium boride, yttrium oxide, and aerogel powder;

[0009] The foaming agent is one or more of aluminum powder, azodicarbonamide (AC), and calcium carbonate;

[0010] The curing agent is one or more of magnesium oxide, zinc oxide, and copper oxide;

[0011] The foam stabilizer is sodium dodecyl sulfonate or polyether silicone oil.

[0012] A method for preparing the above-mentioned phenolic / zirconium aluminum phosphate-based dual-network high-temperature resistant foam includes the following steps:

[0013] Step 1: Add molten phenol and catalyst to a four-necked flask and stir until homogeneous at 70-90°C. Slowly add formaldehyde aqueous solution dropwise to the solution and react for 1-4 hours to obtain a water-soluble phenolic prepolymer. The catalyst is ammonia or sodium hydroxide, and its amount is 1-5% of the molar amount of phenol. The molar ratio of phenol to formaldehyde is 1:1-2. The water-soluble phenolic prepolymer is a thermosetting phenolic resin with a solid content of 70-80%.

[0014] Step 2: Add the water-soluble phenolic prepolymer to the zirconium aluminum phosphate matrix and stir until a homogeneous system is formed to obtain an organic-inorganic matrix, wherein: the amount of water-soluble phenolic prepolymer added is 10-40% of the mass of the zirconium aluminum phosphate matrix;

[0015] Step 3: Mix the high-temperature resistant filler, foaming agent, curing agent, and foam stabilizer evenly, then add them to the organic-inorganic matrix and grind and disperse them evenly to obtain phenolic / zirconium aluminum phosphate based foaming compound, wherein the mass ratio of the high-temperature resistant filler to the organic-inorganic matrix is ​​0.5:1 to 1.5:1;

[0016] Step 4: Pour the phenolic / zirconium aluminum phosphate-based foaming compound into a stainless steel mold coated with a release agent, and let it stand at room temperature for a period of time to achieve foaming expansion and synergistic curing of the dual network, thus obtaining the phenolic / zirconium aluminum phosphate-based dual network high-temperature resistant foaming compound. The foaming and curing process is first placed at room temperature (atmospheric pressure, air humidity 50%, temperature 25℃) for 5 to 15 minutes. By utilizing the synergistic effect of curing exothermic heat and foaming agent decomposition, foaming and curing are carried out simultaneously, forming a porous dual network foaming material with uniform pore size and stable structure.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] 1. Innovative construction of phenolic / zirconium aluminum phosphate dual network structure: This invention uses water-soluble phenolic prepolymer as an organic network, which significantly improves the bonding strength, toughness and compressive strength of the material; Zirconium aluminum phosphate resin is a rigid inorganic network, which gives the material the ability to withstand ultra-high temperature above 1500℃, together constructing an organic-inorganic dual network structure.

[0019] 2. Achieving Simultaneous Foaming and Curing: By controlling the synergistic effect of curing exothermic reaction and foaming agent decomposition, foaming and curing are achieved simultaneously, forming a porous double-network foam material with uniform pore size and stable structure. This material can not only be used as an adhesive, but also enables rapid filling of gaps and on-site molding, making it suitable for efficient construction of complex structures.

[0020] 3. Excellent thermal protection and lightweight properties: After foaming, the density of the material can be reduced to 0.25-0.4 g / cm³, and the foaming ratio can reach 3-6 times, combining lightweight and high strength. The introduction of high-temperature resistant fillers (such as aerogel and zirconium oxide) significantly improves the material's thermal insulation performance and resistance to airflow erosion, making it suitable for extreme conditions such as thermal protection layers for hypersonic vehicles, thermal insulation layers for rocket engines, and high-temperature sealing.

[0021] 4. Expanding the application boundaries of phosphate-based materials: This invention breaks through the limitations of traditional phosphate materials as coatings or adhesives, endowing them with multifunctional properties such as foaming, bonding, and filling, providing a new material solution for the next generation of spacecraft thermal protection systems. Attached Figure Description

[0022] Figure 1 The TG curve of the phenolic / zirconium aluminum phosphate-based dual-network high-temperature resistant foam in Example 1 is shown below.

[0023] Figure 2 This is a photograph of the phenolic / zirconium aluminum phosphate-based dual-network high-temperature resistant foam in Example 1.

[0024] Figure 3 The image shows the phenolic / zirconium aluminum phosphate-based dual-network high-temperature resistant foam in Example 1 after being burned at 1500℃.

[0025] Figure 4 The image shows the actual product of the zirconium aluminum phosphate-based high-temperature resistant foam in Comparative Example 1.

[0026] Figure 5 This is an ablation diagram of the phenolic / aluminum phosphate-based dual-network high-temperature resistant foam in Comparative Example 3 at 1500℃. Detailed Implementation

[0027] The technical solution of the present invention will be further described below with reference to the embodiments, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention.

[0028] All raw materials used in this invention are commercially available. Unless otherwise specified, all figures in the following examples are by weight.

[0029] Example 1

[0030] Step 1: Add 94g of molten phenol and 0.94g of ammonia water to a four-necked flask, stir evenly at 70℃, slowly add 105.5g of formaldehyde aqueous solution to the solution, react for 2h to obtain water-soluble phenolic prepolymer;

[0031] Step 2: Weigh 50 parts of phosphoric acid and 15 parts of deionized water and add them to a three-necked flask. Stir magnetically at 90°C for 20 minutes to dilute the solution. Add 10 parts of aluminum hydroxide and stir magnetically until completely dissolved. Add 5 parts of zirconium oxychloride and 5 parts of citric acid to complex the solution for 2 hours. Stop heating when the solution becomes transparent and viscous. Allow it to cool naturally. The reaction is complete, and zirconium aluminum phosphate matrix is ​​obtained.

[0032] Step 3: Add 15 parts of water-soluble phenolic prepolymer to 50 parts of zirconium aluminum phosphate matrix obtained in Step 2, and stir until a homogeneous system is formed to obtain an organic-inorganic matrix.

[0033] Step 4: Mix 5 parts aerogel powder, 10g alumina, 5 parts zirconium oxide, 3 parts aluminum powder, 5 parts magnesium oxide, and 1 part sodium dodecyl sulfonate evenly, then add it to the organic-inorganic matrix obtained in Step 3, grind and disperse evenly to obtain phenolic / zirconium aluminum phosphate based foaming material.

[0034] Step 5: Pour the adhesive obtained in Step 4 into a stainless steel mold coated with a release agent, and let it stand at room temperature for 10 minutes to achieve foaming expansion and synergistic curing of the dual network, thus obtaining phenolic / zirconium aluminum phosphate-based dual network high-temperature resistant foam.

[0035] The density of the phenolic / zirconium aluminum phosphate-based dual-network high-temperature resistant foam prepared in this embodiment is 0.28 g / cm³. 3 Thermal conductivity is 0.04 W / m·K; compressive strength is 3.8 MPa; TG diagram is shown below. Figure 1 As shown; actual product image as shown Figure 2 As shown; the image shows the product after being burned at 1500℃. Figure 3 As shown.

[0036] Example 2

[0037] Step 1: Add 94g of molten phenol and 0.94g of sodium hydroxide to a four-necked flask and stir evenly at 80℃. Slowly add 135.5g of formaldehyde aqueous solution to the solution and react for 2.5h to obtain water-soluble phenolic prepolymer.

[0038] Step 2: Weigh 50 parts of phosphoric acid and 20 parts of deionized water and add them to a three-necked flask. Stir magnetically at 80°C for 20 minutes to dilute the solution. Add 7.5 parts of aluminum hydroxide and stir magnetically until completely dissolved. Add 4 parts of zirconium oxychloride and 2 parts of citric acid to complex the solution for 3 hours. Stop heating when the solution becomes transparent and viscous. Allow it to cool naturally. The reaction is complete, and the zirconium aluminum phosphate matrix is ​​obtained.

[0039] Step 3: Add 25 parts of water-soluble phenolic prepolymer to 40 parts of zirconium aluminum phosphate matrix obtained in Step 2, and stir until a homogeneous system is formed to obtain an organic-inorganic matrix;

[0040] Step 4: Mix 8 parts aerogel powder, 7 parts boron nitride, 8 parts zirconium oxide, 8 parts AC foaming agent, 5 parts zinc oxide, and 2.5 parts polyether silicone oil evenly, then add them to the organic-inorganic matrix obtained in Step 3, grind and disperse evenly to obtain phenolic / zirconium aluminum phosphate based foaming compound.

[0041] Step 5: Pour the adhesive obtained in Step 4 into a stainless steel mold coated with a release agent, and let it stand at room temperature for 12 minutes to achieve foaming expansion and synergistic curing of the dual network, thus obtaining phenolic / zirconium aluminum phosphate-based dual network high-temperature resistant foam.

[0042] The density of the phenolic / zirconium aluminum phosphate-based dual-network high-temperature resistant foam prepared in this embodiment is 0.3 g / cm³. 3 The thermal conductivity is 0.042 W / m·K; the compressive strength is 3.6 MPa.

[0043] Example 3

[0044] Step 1: Add 94g of molten phenol and 1.88g of ammonia water to a four-necked flask and stir evenly at 90℃. Slowly add 125.5g of formaldehyde aqueous solution to the solution and react for 3 hours to obtain water-soluble phenolic prepolymer.

[0045] Step 2: Weigh 50 parts of phosphoric acid and 10 parts of deionized water and add them to a three-necked flask. Stir magnetically at 100°C for 25 minutes to dilute the solution. Add 15 parts of aluminum hydroxide and stir magnetically until completely dissolved. Add 7.5 parts of zirconium oxychloride and 3 parts of citric acid to complex the solution for 1.5 hours. Stop heating when the solution becomes transparent and viscous. Allow it to cool naturally. The reaction is complete, and the zirconium aluminum phosphate matrix is ​​obtained.

[0046] Step 3: Add 12 parts of water-soluble phenolic prepolymer to 45 parts of zirconium aluminum phosphate matrix obtained in Step 2, and stir until a homogeneous system is formed to obtain an organic-inorganic matrix.

[0047] Step 4: Mix 30 parts of aerogel powder, 10 parts of silicon carbide, 8 parts of zirconium oxide, 2 parts of aluminum powder, 8 parts of magnesium oxide, and 1.5 parts of sodium dodecyl sulfonate evenly, then add it to the organic-inorganic matrix obtained in Step 3, grind and disperse evenly to obtain phenolic / zirconium aluminum phosphate based foaming material.

[0048] Step 5: Pour the adhesive obtained in Step 4 into a stainless steel mold coated with a release agent, and let it stand at room temperature for 10 minutes to achieve foaming expansion and synergistic curing of the dual network, thus obtaining phenolic / zirconium aluminum phosphate-based dual network high-temperature resistant foam.

[0049] The density of the phenolic / zirconium aluminum phosphate-based dual-network high-temperature resistant foam prepared in this embodiment is 0.30 g / cm³. 3 The thermal conductivity is 0.038 W / m·K; the compressive strength is 3.4 MPa.

[0050] Example 4

[0051] Step 1: Add 94g of molten phenol and 2.82g of ammonia water to a four-necked flask and stir evenly at 75°C. Slowly add 145.5g of formaldehyde aqueous solution to the solution and react for 2 hours to obtain water-soluble phenolic prepolymer.

[0052] Step 2: Weigh 50 parts of phosphoric acid and 17.5 parts of deionized water into a three-necked flask, and stir magnetically at 100°C for 25 minutes to dilute it completely. Add 11 parts of aluminum hydroxide and stir magnetically until it is completely dissolved. Add 6 parts of zirconium oxychloride and 2.5 parts of citric acid to complex the solution for 2.5 hours. Stop heating when the solution becomes transparent and viscous, and allow it to cool naturally. The reaction is then complete, and the zirconium aluminum phosphate matrix is ​​obtained.

[0053] Step 3: Add 18 parts of water-soluble phenolic prepolymer to 55 parts of zirconium aluminum phosphate matrix obtained in Step 2, and stir until a homogeneous system is formed to obtain an organic-inorganic matrix.

[0054] Step 4: Mix 15 parts aerogel powder, 8 parts zirconium boride, 15 parts zirconium oxide, 4 parts calcium carbonate, 8 parts zinc oxide, and 1 part polyether silicone oil evenly, then add it to the organic-inorganic matrix obtained in Step 3, grind and disperse evenly to obtain phenolic / zirconium aluminum phosphate based foaming material.

[0055] Step 5: Pour the adhesive obtained in Step 4 into a stainless steel mold coated with a release agent, and let it stand at room temperature for 14 minutes to achieve foaming expansion and synergistic curing of the dual network, thus obtaining phenolic / zirconium aluminum phosphate-based dual network high-temperature resistant foam.

[0056] The density of the phenolic / zirconium aluminum phosphate-based dual-network high-temperature resistant foam prepared in this embodiment is 0.26 g / cm³. 3 The thermal conductivity is 0.042 W / m·K; the compressive strength is 3.9 MPa.

[0057] Example 5

[0058] Step 1: Add 94g of molten phenol and 2.82g of sodium hydroxide to a four-necked flask and stir evenly at 80℃. Slowly add 130.5g of formaldehyde aqueous solution to the solution and react for 3 hours to obtain water-soluble phenolic prepolymer.

[0059] Step 2: Weigh 50 parts of phosphoric acid and 12.5 parts of deionized water and add them to a three-necked flask. Stir magnetically at 95°C for 30 minutes to dilute the solution. Add 12.5 parts of aluminum hydroxide and stir magnetically until completely dissolved. Add 9 parts of zirconium oxychloride and 4 parts of citric acid to complex the solution for 2 hours. Stop heating when the solution becomes transparent and viscous. Allow it to cool naturally. The reaction is complete, and zirconium aluminum phosphate matrix is ​​obtained.

[0060] Step 3: Add 20 parts of water-soluble phenolic prepolymer to 50 parts of zirconium aluminum phosphate matrix obtained in Step 2, and stir until a homogeneous system is formed to obtain an organic-inorganic matrix.

[0061] Step 4: Mix 12 parts aerogel powder, 18 parts yttrium oxide, 9 parts zirconium oxide, 2 parts aluminum powder, 3 parts magnesium oxide, 3 parts zinc oxide, 3 parts AC foaming agent, and 2 parts sodium dodecyl sulfonate evenly, and then add them to the organic-inorganic matrix obtained in Step 3. Grind and disperse evenly to obtain phenolic / zirconium aluminum phosphate based foaming compound.

[0062] Step 5: Pour the adhesive obtained in Step 4 into a stainless steel mold coated with a release agent, and let it stand at room temperature for 8 minutes to achieve foaming expansion and synergistic curing of the dual network, thus obtaining phenolic / zirconium aluminum phosphate-based dual network high-temperature resistant foam.

[0063] The density of the phenolic / zirconium aluminum phosphate-based dual-network high-temperature resistant foam prepared in this embodiment is 0.31 g / cm³. 3 The thermal conductivity is 0.044 W / m·K; the compressive strength is 3.6 MPa.

[0064] Example 6

[0065] Step 1: Add 94g of molten phenol and 0.94g of sodium hydroxide to a four-necked flask and stir evenly at 90℃. Slowly add 145.5g of formaldehyde aqueous solution to the solution and react for 2 hours to obtain water-soluble phenolic prepolymer.

[0066] Step 2: Weigh 50 parts of phosphoric acid and 15 parts of deionized water and add them to a three-necked flask. Stir magnetically at 90°C for 20 minutes to dilute the solution. Add 10 parts of aluminum hydroxide and stir magnetically until completely dissolved. Add 5 parts of zirconium oxychloride and 5 parts of citric acid to complex the solution for 2 hours. Stop heating when the solution becomes transparent and viscous. Allow it to cool naturally. The reaction is complete, and zirconium aluminum phosphate matrix is ​​obtained.

[0067] Step 3: Add 10 parts of water-soluble phenolic prepolymer to 40 parts of zirconium aluminum phosphate matrix obtained in Step 1, and stir until a homogeneous system is formed to obtain an organic-inorganic matrix.

[0068] Step 4: Mix 40 parts of aerogel powder, 3 parts of aluminum powder, 4 parts of magnesium oxide, 4 parts of zinc oxide, and 1.5 parts of sodium dodecyl sulfonate evenly, then add it to the organic-inorganic matrix obtained in Step 2, grind and disperse evenly to obtain phenolic / zirconium aluminum phosphate based foaming material.

[0069] Step 5: Pour the adhesive obtained in Step 3 into a stainless steel mold coated with a release agent, and let it stand at room temperature for 12 minutes to achieve foaming expansion and synergistic curing of the dual network, thus obtaining phenolic / zirconium aluminum phosphate-based dual network high-temperature resistant foam.

[0070] The density of the phenolic / zirconium aluminum phosphate-based dual-network high-temperature resistant foam prepared in this embodiment is 0.25 g / cm³. 3 The thermal conductivity is 0.044 W / m·K; the compressive strength is 3.4 MPa.

[0071] Comparative Example 1

[0072] Step 1: Weigh 50 parts of phosphoric acid and 15 parts of deionized water and add them to a three-necked flask. Stir magnetically at 90°C for 20 minutes to dilute the solution. Add 10 parts of aluminum hydroxide and stir magnetically until completely dissolved. Add 5 parts of zirconium oxychloride and 5 parts of citric acid to complex the solution for 2 hours. Stop heating when the solution becomes transparent and viscous. Allow it to cool naturally. The reaction is complete, and zirconium aluminum phosphate matrix is ​​obtained.

[0073] Step 2: Mix 5 parts aerogel powder, 10g alumina, 5 parts zirconium oxide, 3 parts aluminum powder, 5 parts magnesium oxide, and 1 part sodium dodecyl sulfonate evenly, then add it to the zirconium aluminum phosphate matrix obtained in Step 1, grind and disperse evenly to obtain zirconium aluminum phosphate based foaming material.

[0074] Step 3: Pour the adhesive obtained in Step 2 into a stainless steel mold coated with a release agent, and let it stand at room temperature for 10 minutes to achieve foaming expansion and synergistic curing, thus obtaining a zirconium aluminum phosphate-based high-temperature resistant foam.

[0075] The density of the zirconium aluminum phosphate-based high-temperature resistant foam prepared in this comparative example is 0.20 g / cm³. 3 Thermal conductivity is 0.039 W / m·K; compressive strength is 2.4 MPa; physical image as shown. Figure 4 As shown.

[0076] Comparative Example 2

[0077] Step 1: Add 94g of molten phenol and 0.94g of sodium hydroxide to a four-necked flask and stir evenly at 80°C. Slowly add 135.5g of formaldehyde aqueous solution to the solution and react for 2.5h to obtain water-soluble phenolic prepolymer.

[0078] Step 2: Weigh 50 parts of phosphoric acid and 20 parts of deionized water and add them to a three-necked flask. Stir magnetically at 80°C for 20 minutes to dilute the solution. Add 7.5 parts of aluminum hydroxide and stir magnetically until completely dissolved. Add 4 parts of zirconium oxychloride and 2 parts of citric acid to complex the solution for 3 hours. Stop heating when the solution becomes transparent and viscous. Allow it to cool naturally. The reaction is complete, and the zirconium aluminum phosphate matrix is ​​obtained.

[0079] Step 3: Add 25 parts of water-soluble phenolic prepolymer to 40 parts of zirconium aluminum phosphate matrix obtained in Step 2, and stir until a homogeneous system is formed to obtain an organic-inorganic matrix;

[0080] Step 4: Mix 8 parts alumina powder, 7 parts boron nitride, 8 parts zirconium oxide, 8 parts AC foaming agent, 6 parts zinc oxide, and 2.5 parts polyether silicone oil evenly, then add them to the organic-inorganic matrix obtained in Step 3, grind and disperse evenly to obtain phenolic / zirconium aluminum phosphate based foaming compound.

[0081] Step 5: Pour the adhesive obtained in Step 4 into a stainless steel mold coated with a release agent, and let it stand at room temperature for 12 minutes to achieve foaming expansion and synergistic curing of the dual network, thus obtaining phenolic / zirconium aluminum phosphate-based dual network high-temperature resistant foam.

[0082] The density of the phenolic / zirconium aluminum phosphate-based dual-network high-temperature resistant foam prepared in this comparative example is 0.27 g / cm³. 3 The thermal conductivity is 0.048 W / m·K; the compressive strength is 3.6 MPa.

[0083] Comparative Example 3

[0084] Step 1: Add 94g of molten phenol and 2.82g of sodium hydroxide to a four-necked flask and stir evenly at 80°C. Slowly add 130.5g of formaldehyde aqueous solution to the solution and react for 3 hours to obtain water-soluble phenolic prepolymer.

[0085] Step 2: Weigh 50 parts of phosphoric acid and 15 parts of deionized water and add them to a three-necked flask. Stir magnetically at 90°C for 20 minutes to dilute the solution. Add 10 parts of aluminum hydroxide and stir magnetically until completely dissolved. Stop heating when the solution becomes transparent and viscous. Allow it to cool naturally. The reaction is complete, and the aluminum phosphate matrix is ​​obtained.

[0086] Step 3: Add 15 parts of water-soluble phenolic prepolymer to 50 parts of aluminum phosphate matrix obtained in Step 2, and stir until a homogeneous system is formed to obtain an organic-inorganic matrix.

[0087] Step 4: Mix 5 parts aerogel powder, 10g alumina, 5 parts zirconium oxide, 3 parts aluminum powder, 3 parts magnesium oxide, 3 parts zinc oxide, and 1 part sodium dodecyl sulfonate evenly, then add it to the organic-inorganic matrix obtained in Step 3, grind and disperse evenly to obtain phenolic / aluminum phosphate based foaming material.

[0088] Step 5: Pour the adhesive obtained in Step 4 into a stainless steel mold coated with a release agent, and let it stand at room temperature for 10 minutes to achieve foaming expansion and synergistic curing of the dual network, thus obtaining a phenolic / aluminum phosphate-based dual network high-temperature resistant foam.

[0089] The density of the phenolic / zirconium aluminum phosphate-based dual-network high-temperature resistant foam prepared in this comparative example is 0.25 g / cm³. 3 The thermal conductivity is 0.038 W / m·K; the compressive strength is 3.5 MPa; the ablation diagram at 1500℃ is shown below. Figure 5 As shown.

[0090] As can be seen from the above examples and comparative examples, water-soluble phenolic prepolymer is crucial as an organic network. If this component is missing (as in Comparative Example 1), the material cannot form a double-network structure, directly leading to a loss of essential structural toughness and a significant decrease in compressive strength. The introduction of functional high-temperature resistant fillers such as aerogel plays a key role in heat insulation. If replaced with conventional fillers (as in Comparative Example 2), the thermal conductivity of the material will increase significantly, and the thermal insulation performance will deteriorate markedly. The addition of zirconium in the zirconium aluminum phosphate inorganic system (as in Comparative Example 3, where zirconium is missing) is the core foundation for constructing a stable and rigid inorganic skeleton and endowing the material with resistance to extreme ultra-high temperature environments of 1500℃. This foam, through the precise coupling of the organic and inorganic networks and the synergy of functional fillers, successfully breaks through the performance bottlenecks of traditional materials, perfectly balancing excellent comprehensive performance with low density and lightweight, high compressive strength, extremely low thermal conductivity, and resistance to ultra-high temperatures.

Claims

1. A phenolic / zirconium aluminum phosphate-based dual-network high-temperature resistant foam, characterized in that... The foaming adhesive comprises 40-60 parts by weight of zirconium aluminum phosphate matrix, 10-30 parts by weight of water-soluble phenolic prepolymer, 20-50 parts by weight of high-temperature resistant filler, 1-10 parts by weight of foaming agent, 1-10 parts by weight of curing agent and 0.1-3 parts by weight of foam stabilizer.

2. The phenolic / zirconium aluminum phosphate based dual-network high-temperature resistant foam according to claim 1, characterized in that... The inorganic matrix of zirconium aluminum phosphate is prepared from the following raw materials by weight: 100 parts phosphoric acid, 10-30 parts aluminum hydroxide, 5-20 parts zirconium oxychloride, 1-10 parts citric acid, and 20-50 parts deionized water.

3. The phenolic / zirconium aluminum phosphate based dual-network high-temperature resistant foam according to claim 2, characterized in that... The specific preparation steps of the zirconium aluminum phosphate matrix are as follows: Weigh phosphoric acid and deionized water into a three-necked flask, stir magnetically at a constant temperature of 80-100℃ to dilute it fully, add aluminum hydroxide and stir magnetically at a constant temperature until it is completely dissolved, add zirconium oxychloride and citric acid to complex and react for 1-3 hours to obtain the zirconium aluminum phosphate matrix.

4. The phenolic / zirconium aluminum phosphate based dual-network high-temperature resistant foam according to claim 1, characterized in that... The high-temperature resistant filler is selected from one or more of alumina, silicon dioxide, silicon carbide, boron nitride, quartz powder, zirconium oxide, zirconium boride, yttrium oxide, and aerogel powder; the foaming agent is one or more of aluminum powder, azodicarbonamide, and calcium carbonate; the curing agent is one or more of magnesium oxide, zinc oxide, and copper oxide; and the foam stabilizer is sodium dodecyl sulfonate or polyether silicone oil.

5. A method for preparing the phenolic / zirconium aluminum phosphate-based dual-network high-temperature resistant foam according to any one of claims 1-4, characterized in that... The method includes the following steps: Step 1: Add molten phenol and catalyst to a four-necked flask and stir evenly at 70~90℃. Slowly add formaldehyde aqueous solution to the solution and react for 1~4 hours to obtain water-soluble phenolic prepolymer. Step 2: Add the water-soluble phenolic prepolymer to the zirconium aluminum phosphate matrix and stir until a homogeneous system is formed to obtain an organic-inorganic matrix; Step 3: Mix the high-temperature resistant filler, foaming agent, curing agent, and foam stabilizer evenly, then add them to the organic-inorganic matrix, grind and disperse evenly to obtain phenolic / zirconium aluminum phosphate based foaming compound; Step 4: Pour the phenolic / zirconium aluminum phosphate-based foaming compound into a stainless steel mold coated with a release agent, and let it stand at room temperature to achieve foaming expansion and synergistic curing of the dual network, thus obtaining the phenolic / zirconium aluminum phosphate-based dual network high-temperature resistant foaming compound.

6. The preparation method of the phenolic / zirconium aluminum phosphate-based dual-network high-temperature resistant foam according to claim 5, characterized in that... In step one, the catalyst is ammonia or sodium hydroxide, and the amount used is 1-5% of the amount of phenol; the molar ratio of phenol to formaldehyde is 1:1-2.

7. The preparation method of the phenolic / zirconium aluminum phosphate-based dual-network high-temperature resistant foam according to claim 5, characterized in that... In step one, the water-soluble phenolic prepolymer is a thermosetting phenolic resin with a solid content of 70-80%.

8. The preparation method of the phenolic / zirconium aluminum phosphate-based dual-network high-temperature resistant foam according to claim 5, characterized in that... In step two, the amount of water-soluble phenolic prepolymer added is 10-40% of the mass of the zirconium aluminum phosphate matrix.

9. The preparation method of the phenolic / zirconium aluminum phosphate-based dual-network high-temperature resistant foam according to claim 5, characterized in that... In step three, the mass ratio of the high-temperature resistant filler to the organic-inorganic matrix is ​​0.5:1 to 1.5:

1.

10. The preparation method of the phenolic / zirconium aluminum phosphate-based dual-network high-temperature resistant foam according to claim 5, characterized in that... In step four, the standing time at room temperature is 5 to 15 minutes.

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