Polyether ether ketone-based composite aerogel and preparation method and application thereof

Abstract

The application belongs to the technical field of nanometer material polymer-based porous composite aerogel, and discloses a polyether ether ketone-based composite aerogel as well as a preparation method and application thereof. The method comprises the following steps: mixing polyether ether ketone powder, functional fillers and a high-boiling-point solvent, and stirring at 280-340 DEG C for 2-6 hours under inert gas to obtain a polyether ether ketone mixed sol; hot injection into a mold, and placing the mold in a constant-temperature environment at 40-60 DEG C for 15-60 minutes to form a wet gel block containing solvent; after the wet gel block is demolded, the following two-step solvent replacement is performed: removing the high-boiling-point solvent and water phase replacement, and finally freeze-drying to obtain the polyether ether ketone-based composite aerogel which has excellent mechanical properties, high thermal stability, good flame retardancy and various functions.

Description

Technical Field

[0001] This invention belongs to the field of nanomaterial polymer-based porous composite aerogel technology, and specifically relates to a polyether ether ketone-based composite aerogel, its preparation method and application. Background Technology

[0002] In recent years, aerogels have been recognized for their high porosity (80-99.8%) and high specific surface area (200-1000 m²). 2 / g), low density (<0.1g / cm³) 3 Its properties, such as high thermal conductivity (<0.05 W / (m·K)), indicate broad application prospects in flame retardancy, heat insulation, and sound insulation. Currently, the most widely studied aerogels are inorganic aerogels with silica (SiO2) as the matrix material. Although SiO2 aerogels have excellent high-temperature stability and low thermal conductivity, their application is limited due to complex preparation processes, high costs, and fragility.

[0003] Compared to traditional SiO2 aerogels, polymer-based aerogels have become a research focus in the field of multifunctional aerogels due to their superior processing flexibility and designable molecular network structures. However, limited by the physicochemical properties of the polymer matrix itself, existing polymer-based aerogels typically have low compressive moduli and low thermal stability due to limited skeletal strength, with thermal decomposition temperatures generally below 270℃, making them unsuitable for long-term service in high-temperature environments. Furthermore, the limiting oxygen index (LOI) of traditional polymer-based aerogels is generally below 34, exhibiting a high fire hazard. Therefore, the development of novel polymer composite aerogels that combine high strength, high heat resistance, and synergistic flame retardant properties is currently an urgent need.

[0004] Polyetheretherketone (PEEK), as a specialty engineering plastic, possesses outstanding comprehensive performance advantages: its melting point is as high as 334℃, its glass transition temperature is 143℃, and its thermal decomposition temperature is significantly higher than that of traditional polymer materials, exhibiting excellent high-temperature resistance; it also possesses a tensile strength of 132-148MPa, with mechanical properties far exceeding those of conventional polymer matrices, and combines good chemical stability and environmental friendliness, making it an ideal choice for constructing high-performance aerogel matrices. Existing research has shown that PEEK can be induced by benign solvents to form aerogels with a three-dimensional network structure, achieving a porosity of 80-93%, a specific surface area of ​​200-225 m² / g, and a density between 0.09-0.25 g / cm³, demonstrating its potential application value as an aerogel matrix.

[0005] While the PEEK matrix provides a good foundation for improving aerogel properties, single PEEK aerogels still suffer from limited functionality and unoptimized performance in some areas, necessitating composite modification to further enhance their overall performance. Existing research has found that combining nanoparticles with PEEK can achieve synergistic performance enhancement; however, the uniform dispersion of nanofillers within the PEEK matrix remains a key technical challenge—nanoparticles are prone to aggregation due to surface tension, which not only fails to exert their reinforcing effect but may also form defect sites, affecting the overall performance of the aerogel. Furthermore, the preparation of existing PEEK aerogels often relies on toxic and harmful solvents, limiting their environmental friendliness and potential for large-scale production. Developing green and environmentally friendly preparation processes is also an important direction for current research. Summary of the Invention

[0006] In order to overcome the shortcomings and deficiencies of the prior art, the primary objective of this invention is to provide a method for preparing polyether ether ketone-based composite aerogels.

[0007] Another object of the present invention is to provide a polyether ether ketone-based composite aerogel prepared by the above preparation method.

[0008] Another object of the present invention is to provide an application of the above-mentioned polyetheretherketone-based composite aerogel.

[0009] The objective of this invention is achieved through the following technical solution: A method for preparing a polyetheretherketone-based composite aerogel, comprising the following steps: (1) Weigh out polyether ether ketone (PEEK) powder, functional filler and high boiling point solvent and mix them; under inert gas protection, heat the resulting mixture to 280-340℃ and stir at this temperature for 2-6 hours until the polyether ether ketone powder is completely dissolved and the functional filler is evenly dispersed to obtain polyether ether ketone mixed sol. The high-boiling-point solvent is dibenzyl ketone (also known as 1,3-diphenylpropanone, DPA). The functional filler is one or more of carbon nanotubes (CNTs), nano-silica (SiO2), boron nitride nanosheets (BN), and nano-alumina (Al2O3); The mass concentration of the polyetheretherketone powder in the high-boiling-point solvent is 10%-25%; The amount of the functional filler added is 1%-10% of the mass of polyetheretherketone; (2) The polyether ether ketone mixed sol obtained in step (1) is injected into the mold while hot, and then the mold is placed in a constant temperature environment of 40-60℃ for 15-60 minutes to carry out thermal phase separation and crystallization to form a wet gel block containing solvent.

[0010] (3) After demolding the wet gel block obtained in step (2), perform the following two-step solvent replacement: The first stage of replacement is to remove high-boiling-point solvents. Specifically, the wet gel block is placed in a Soxhlet extractor, and ethanol is used as the extractant. Extraction is carried out under reflux conditions for 48-96 hours to remove dibenzyl ketone (DPA) from the gel pores. The second-stage replacement is aqueous phase replacement. Specifically, the gel block after the first-stage replacement is placed in deionized water and immersed in it at 100-200℃ for 48-96 hours to completely replace the ethanol with water, resulting in a wet gel. The wet gel is then frozen overnight at -28℃ and freeze-dried for 48 hours to remove the water, yielding a polyether ether ketone composite aerogel.

[0011] In step (1), the mixture is heated to 320°C and stirred at that temperature for 4 hours; the inert gas is nitrogen; the amount of the functional filler added is 5% of the mass of polyether ether ketone.

[0012] The constant temperature environment mentioned in step (2) refers to a 50°C constant temperature water bath; the settling time is 30 minutes.

[0013] The heating reflux conditions in step (3) are carried out in an ethanol bath at 100°C; the extraction time is 72 hours; and the soaking and displacement time is 72 hours.

[0014] A polyether ether ketone-based composite aerogel prepared by the above preparation method.

[0015] The above-mentioned polyether ether ketone-based composite aerogels are used in thermal insulation and flame retardant materials.

[0016] The principle of this invention: Compared with the prior art, the present invention has the following advantages and beneficial effects: (1) Green and safe process: The present invention adopts DPA / ethanol / water system, which eliminates strong acid, highly toxic and highly polluting solvents. The solvent can be recycled and is environmentally friendly.

[0017] (2) Good structural integrity: This invention combines TIPS method with freeze drying, avoiding the shrinkage of normal pressure drying, and the resulting aerogel has low density and high porosity.

[0018] (3) Adjustable performance: By adding different nanofillers, this invention achieves on-demand control and functional customization of the thermal conductivity, density and mechanical strength of aerogel.

[0019] (4) The method of the present invention selects PEEK with high mechanical properties and high heat resistance as the matrix, combines it with functional nanoparticles, uses a good green solvent, and optimizes the preparation process to achieve uniform dispersion of nanofillers in the matrix, thereby obtaining a composite aerogel with excellent mechanical properties, high thermal stability, good flame retardancy and functional diversity. Attached Figure Description

[0020] Figure 1 Scanning electron microscope image of PEEK-15wt% aerogel; Figure 2 Scanning electron microscope image of PEEK-CNT-5wt% composite aerogel; Figure 3 Scanning electron microscope image of PEEK-SiO2-5wt% composite aerogel; Figure 4 Scanning electron microscope image of PEEK-BN-5wt% composite aerogel; Figure 5 Scanning electron microscope image of PEEK-Al2O3-5wt% composite aerogel. Detailed Implementation

[0021] The following specific embodiments further illustrate the content of the present invention, but should not be construed as limiting the present invention.

[0022] Example 1 Take 20g of dibenzyl ketone and add 3g of polyether ether ketone powder. Under a nitrogen atmosphere, gradually raise the temperature to 320℃ and stir for 4 hours until the polyether ether ketone powder is completely dissolved and the functional filler is evenly dispersed to obtain a polyether ether ketone mixed sol. Pour the obtained polyether ether ketone mixed sol into a columnar glass mold while it is still hot, and then place the mold in a 50℃ water bath to allow the sol-gel transition to occur for 30 minutes. Perform thermally induced phase separation and crystallization to form a wet gel block containing solvent. A columnar wet gel block was placed in a Soxhlet extractor, and ethanol was used as the extractant. The gel was heated under reflux at 100°C for 72 hours to replace the solvent dibenzyl ketone (DPA) in the gel pores. The gel block was then placed in a water bath at 150°C for 72 hours to replace the ethanol. After solvent replacement, the gel was frozen overnight at -28°C and then freeze-dried for 48 hours to remove water, yielding a polyether ether ketone (PEEK) composite aerogel, denoted as PEEK-15wt%, indicating a PEEK mass fraction of 5wt%. The thermal decomposition temperature was determined using a thermogravimetric analyzer, and the results are shown in Table 1. The compressive properties were tested using a universal testing machine, and the compressive strength and compressive modulus were recorded, as shown in Table 2. The thermal conductivity and specific heat capacity were determined using a thermal constant analyzer, and the results are shown in Table 3. Scanning electron microscopy (SEM) images are shown below. Figure 1 As shown, the PEEK aerogel with a solid content of 15 wt% is in the form of nanofibers with an average fiber diameter of 50~200 nm. The fibers form a stable isotropic network structure through cross-fusion and entanglement.

[0023] Example 2 Take 20g of dibenzyl ketone, add 3g of polyether ether ketone powder and 0.15g of carbon nanotube powder (CNT), and gradually heat to 320℃ under a nitrogen atmosphere. Stir for 4h until the polyether ether ketone powder is completely dissolved and the functional filler is evenly dispersed to obtain a polyether ether ketone mixed sol. Pour the obtained polyether ether ketone mixed sol into a columnar glass mold while it is still hot, and then place the mold in a 50℃ water bath to allow the sol-gel transition to occur for 30min. Perform thermally induced phase separation and crystallization to form a wet gel block containing solvent. A columnar wet gel block was placed in a Soxhlet extractor, and ethanol was used as the extractant. The gel was heated under reflux at 100°C for 72 hours to replace the solvent dibenzyl ketone (DPA) in the gel pores. The gel block was then placed in a water bath at 150°C for 72 hours to replace the ethanol. After solvent replacement, the gel was frozen overnight at -28°C and then freeze-dried for 48 hours to remove water, yielding a polyether ether ketone (PEEK) composite aerogel, denoted as PEEK-CNT-5wt%, indicating that the functional filler CNT accounts for 5wt% of the PEEK mass in the composite aerogel. The thermal decomposition temperature was determined using a thermogravimetric analyzer, and the results are shown in Table 1. The compressive properties were tested using a universal testing machine, and the compressive strength and compressive modulus were recorded, as shown in Table 2. The thermal conductivity and specific heat capacity were determined using a thermal constant analyzer, and the results are shown in Table 3. Scanning electron microscopy morphology images are shown below. Figure 2 As shown, carbon nanotubes and polyetheretherketone matrix form good compatibility and synergistic assembly, forming a three-dimensional skeleton with higher apparent roughness and local fiber bundles. The diameter of the composite fiber / fiber bundle is distributed in 100~400 nm, and there is no obvious macroscopic aggregation of CNTs.

[0024] Example 3 Take 20g of dibenzyl ketone, add 3g of polyether ether ketone powder and 0.15g of nano-SiO2 powder, and gradually heat to 320℃ under a nitrogen atmosphere. Stir for 4h until the polyether ether ketone powder is completely dissolved and the functional filler is evenly dispersed to obtain a polyether ether ketone mixed sol. Pour the obtained polyether ether ketone mixed sol into a columnar glass mold while it is still hot, and then place the mold in a 50℃ water bath to allow the sol-gel transition to occur for 30min. Perform thermally induced phase separation and crystallization to form a wet gel block containing solvent. A columnar wet gel block was placed in a Soxhlet extractor, and ethanol was used as the extractant. The gel was heated under reflux at 100°C for 72 hours to replace the solvent dibenzyl ketone (DPA) in the gel pores. The gel block was then placed in a water bath at 150°C for 72 hours to replace the ethanol. After solvent replacement, the gel was frozen overnight at -28°C and then freeze-dried for 48 hours to remove water, yielding a polyether ether ketone (PEEK) composite aerogel, denoted as PEEK-SiO2-5wt%, indicating that the functional filler SiO2 accounts for 5wt% of the PEEK mass in the composite aerogel. The thermal decomposition temperature was determined using a thermogravimetric analyzer, and the results are shown in Table 1. The compressive properties were tested using a universal testing machine, and the compressive strength and compressive modulus were recorded, as shown in Table 2. The thermal conductivity and specific heat capacity were determined using a thermal constant analyzer, and the results are shown in Table 3. Scanning electron microscopy morphology images are shown below. Figure 3 As shown, the PEEK-SiO2-5wt% composite aerogel exhibits a coral-like three-dimensional interconnected porous network structure formed by the co-assembly of nano-silica and polyetheretherketone.

[0025] Example 4 Take 20g of dibenzyl ketone, add 3g of polyether ether ketone powder and 0.15g of boron nitride nanosheets (BN), and gradually heat to 320℃ under a nitrogen atmosphere. Stir for 4h until the polyether ether ketone powder is completely dissolved and the functional filler is evenly dispersed to obtain a polyether ether ketone mixed sol. Pour the obtained polyether ether ketone mixed sol into a columnar glass mold while it is still hot, and then place the mold in a 50℃ water bath to allow the sol-gel transition to occur for 30min. Perform thermally induced phase separation and crystallization to form a wet gel block containing solvent. A columnar wet gel block was placed in a Soxhlet extractor, and ethanol was used as the extractant. The gel was heated under reflux at 100°C for 72 hours to replace the solvent dibenzyl ketone (DPA) in the gel pores. The gel block was then placed in a water bath at 150°C for 72 hours to replace the ethanol. After solvent replacement, the gel was frozen overnight at -28°C and then freeze-dried for 48 hours to remove water, yielding a polyether ether ketone (PEEK) composite aerogel, denoted as PEEK-BN-5wt%, indicating that the functional filler BN accounts for 5wt% of the mass of PEEK in the composite aerogel. The thermal decomposition temperature was determined using a thermogravimetric analyzer, and the results are shown in Table 1. The compressive properties were tested using a universal testing machine, and the compressive strength and compressive modulus were recorded, as shown in Table 2. The thermal conductivity and specific heat capacity were determined using a thermal constant analyzer, and the results are shown in Table 3. Scanning electron microscopy morphology images are shown below. Figure 4 As shown, the PEEK-BN-5wt% composite aerogel exhibits a highly interconnected and isotropic three-dimensional cross-linked nanofiber network structure.

[0026] Example 5 Take 20g of dibenzyl ketone, add 3g of polyether ether ketone powder and 0.15g of nano-Al2O3, and gradually heat to 320℃ under a nitrogen atmosphere. Stir for 4h until the polyether ether ketone powder is completely dissolved and the functional filler is evenly dispersed to obtain a polyether ether ketone mixed sol. Pour the obtained polyether ether ketone mixed sol into a columnar glass mold while it is still hot, and then place the mold in a 50℃ water bath to allow the sol-gel transition to occur for 30min. Perform thermally induced phase separation and crystallization to form a wet gel block containing solvent. A columnar wet gel block was placed in a Soxhlet extractor, and ethanol was used as the extractant. The gel was heated under reflux at 100°C for 72 hours to replace the solvent dibenzyl ketone (DPA) in the gel pores. The gel block was then placed in a water bath at 150°C for 72 hours to replace the ethanol. After solvent replacement, the gel was frozen overnight at -28°C and then freeze-dried for 48 hours to remove water, yielding a polyether ether ketone (PEEK) composite aerogel, denoted as PEEK-Al₂O₃-5wt%, indicating that the functional filler Al₂O₃ accounts for 5wt% of the mass of PEEK in the composite aerogel. The thermal decomposition temperature was determined using a thermogravimetric analyzer, and the results are shown in Table 1. The compressive properties were tested using a universal testing machine, and the compressive strength and compressive modulus were recorded, as shown in Table 2. The thermal conductivity and specific heat capacity were determined using a thermal constant analyzer, and the results are shown in Table 3. Scanning electron microscopy morphology images are shown below. Figure 5 As shown, the PEEK-Al2O3-5wt% composite aerogel has a three-dimensional interconnected porous network framework constructed from Al2O3 nanoparticles and PEEK. The Al2O3 nanoparticles are uniformly anchored on the surface and at the intersections of the PEEK framework. The branch diameter of the composite framework is 100~300 nm, and the through pore size of the porous network is 0.1~1.0 μm.

[0027] As shown in Table 1-3, the introduction of 5 wt% functional filler can simultaneously improve the thermal stability, mechanical strength, and thermal insulation performance of PEEK aerogel. Among them, the modified group PEEK-Al2O3-5wt% showed the best overall performance in improving mechanical strength and reducing thermal conductivity; the BN modified group (PEEK-BN-5wt%) showed the most outstanding performance in terms of high-temperature decomposition resistance and heat storage specific heat capacity.

[0028] Table 1 Thermal decomposition temperatures of polyetheretherketone composite aerogels

[0029] Table 2 Compressive strength and compressive modulus of polyetheretherketone (PEEK) composite aerogels

[0030] Table 3 Compressive strength and compressive modulus of polyetheretherketone (PEEK) composite aerogels

[0031] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations and simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a polyetheretherketone-based composite aerogel, characterized in that... Follow these steps: (1) Weigh out polyether ether ketone powder, functional filler and high boiling point solvent and mix them; under inert gas protection, heat the resulting mixture to 280-340℃ and stir at this temperature for 2-6 hours until the polyether ether ketone powder is completely dissolved and the functional filler is evenly dispersed to obtain polyether ether ketone mixed sol. The high-boiling-point solvent is dibenzyl methyl ketone; The functional filler is one or more of carbon nanotubes, nano-silica, boron nitride nanosheets, and nano-alumina; The mass concentration of the polyetheretherketone powder in the high-boiling-point solvent is 10%-25%; The amount of the functional filler added is 1%-10% of the mass of polyetheretherketone; (2) The polyether ether ketone mixed sol obtained in step (1) is injected into a glass mold while hot, and then the mold is placed in a constant temperature environment of 40-60℃ for 15-60 minutes to carry out thermal phase separation and crystallization to form a wet gel block containing solvent. (3) After demolding the wet gel block obtained in step (2), perform the following two-step solvent replacement: The first stage of replacement is to remove high-boiling-point solvents. Specifically, the wet gel block is placed in a Soxhlet extractor, and ethanol is used as the extractant. Extraction is carried out under reflux conditions for 48-96 hours to remove dibenzyl ketone from the gel pores. The second-stage replacement is aqueous phase replacement. Specifically, the gel block after the first-stage replacement is placed in deionized water and immersed in it at 100-200℃ for 48-96 hours to completely replace the ethanol with water, resulting in a wet gel. The wet gel is then frozen overnight at -28℃ and freeze-dried for 48 hours to remove the water, yielding a polyether ether ketone composite aerogel.

2. The method for preparing a polyetheretherketone-based composite aerogel according to claim 1, characterized in that: In step (1), the mixture is heated to 320°C and stirred at that temperature for 4 hours; the inert gas is nitrogen; the amount of the functional filler added is 5% of the mass of polyether ether ketone.

3. The method for preparing a polyetheretherketone-based composite aerogel according to claim 1, characterized in that: The constant temperature environment mentioned in step (2) refers to a 50°C constant temperature water bath; the settling time is 30 minutes.

4. The method for preparing a polyetheretherketone-based composite aerogel according to claim 1, characterized in that: The heating reflux conditions in step (3) are carried out in an ethanol bath at 100°C; the extraction time is 72 hours; and the soaking and displacement time is 72 hours.

5. The method for preparing a polyetheretherketone-based composite aerogel according to claim 1, characterized in that: The soaking and replacement in step (3) is carried out under heating conditions at 150°C.

6. A polyether ether ketone-based composite aerogel prepared by the preparation method according to any one of claims 1-5.

7. The application of the polyetheretherketone-based composite aerogel according to claim 6 in thermal insulation and flame retardant materials.

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