Atomic oxygen-resistant polyether-ether-ketone material for aviation, preparation method thereof and composite material

Abstract

The invention relates to the technical field of material modification, in particular to an atomic oxygen-resistant polyether-ether-ketone material for aviation, a preparation method of the atomic oxygen-resistant polyether-ether-ketone material and a composite material, and the atomic oxygen-resistant polyether-ether-ketone material is specifically prepared by the following steps: synthesizing a monomer with a silicon functional group on a side chain through a chemical modification method, and then introducing a silicon element into the side chain of a polyether-ether-ketone molecule through a copolymerization method; when the polymer is irradiated by atomic oxygen, side-chain silicon generates an inert inorganic silicon oxide layer on the surface of the polymer material in situ, so that further erosion of atomic oxygen to the surface of the material is inhibited, and the polymer has relatively good atomic oxygen resistance.

Description

Technical Field

[0001] The invention relates to the technical field of material modification, and in particular to an atomic oxygen-resistant polyetheretherketone material for aviation, a preparation method thereof, and a composite material. Background Art

[0002] The height of the Earth's atmosphere is about 1000km. The low Earth orbit is located in the encirclement of the atmosphere, 200-700km from the Earth's surface. A large number of artificial satellites and space stations operate in the low Earth orbit area. However, the presence of atomic oxygen (AO) in the low Earth orbit space environment makes the space environment very harsh. Atomic oxygen has extremely strong oxidizing properties, which is much stronger than molecular oxygen. In addition, the collision kinetic energy of atomic oxygen is 5.3eV, and the effect produced is similar to that of 4.8×10 4 The high temperature of K is close. This strong high-temperature oxidation and high-speed collision will cause serious erosion to the organic polymer material on the surface of the aircraft and destroy the internal structure of the material, eventually causing the service life of the aircraft to decrease and affecting the performance of the aircraft. Therefore, improving the atomic resistance of organic polymer materials used in aerospace has always been a research hotspot for aerospace researchers.

[0003] Polyetheretherketone (PEEK) is a semi-crystalline, thermoplastic aromatic special engineering plastic with a linear main molecular chain. It has excellent properties such as heat resistance, chemical corrosion resistance, wear resistance, fatigue resistance, and hydrolysis resistance. It has been widely used in the aerospace field, such as aircraft torque motors, control gyroscopes, sliders, reversing bearings, and solar energy and antenna drive devices. Experiments have shown that under long-term exposure to atomic oxygen, PEEK materials exhibit a high erosion rate, which seriously affects the long-term, efficient and safe operation of aircraft. For this reason, the development of atomic oxygen-resistant polyetheretherketone resins suitable for the aviation field is of great significance to the development of my country's aviation industry. Patent CN202110350124.2 describes a composite anti-atomic oxygen polyimide; there is currently no report on patents related to intrinsic atomic oxygen-resistant polyetheretherketone in China. Summary of the invention

[0004] In order to solve the above technical problems, an atomic oxygen resistant polyetheretherketone material for aviation and its preparation method and composite material are provided. The polymer of the present invention has good atomic oxygen resistance.

[0005] In order to achieve the above objectives, the present invention is implemented by the following technical solutions:

[0006] A method for preparing an atomic oxygen-resistant polyetheretherketone material for aviation, comprising the following steps:

[0007] A part of fluoroketone raw materials is replaced by difluoro monomers containing silicon side chains, and atomic oxygen resistant polyetheretherketone materials for aviation are obtained through copolymerization and condensation.

[0008] Further, it specifically includes the following steps:

[0009] Under a protective atmosphere, hydroquinone and a salifying agent are placed in a solvent and heated to dissolve until no bubbles are generated. 4,4'-difluorobenzophenone and a difluoro monomer with a silicon-containing side chain are added to form a reaction system, and the temperature is continuously raised for copolymerization condensation reaction. After the reaction is completed, the product is precipitated with water to obtain an atomic oxygen-resistant polyether ether ketone material for aviation.

[0010] Still further, the chemical structure of the difluoro monomer with a silicon-containing side chain is as follows:

[0011]

[0012] Wherein R 1 , R 2 , R 3 are selected from one of the same alkyl group, phenyl group, and benzyl group, or R 1 , R 2 , R 3 are all selected from alkyl groups and two of them are the same alkyl group, and the alkyl group is a normal or isomeric alkyl group with less than 5 carbon atoms.

[0013] Still further, the difluoro monomer with a silicon-containing side chain is obtained by the following method: Under a protective atmosphere, difluorobenzhydrol is added to a benzene solvent. After complete dissolution and uniformity, an excessive amount of chlorosilane in molar ratio is added and reacted at a temperature below 60 °C for 1 - 2 h. Then the temperature is raised to above 100 °C to evaporate the benzene solvent and unreacted chlorosilane, and the product is cooled and crystallized to obtain the difluoro monomer with a silicon-containing side chain.

[0014] Still further, the chlorosilane is selected from one of trimethylchlorosilane, triethylchlorosilane, tri-n-propylchlorosilane, triisopropylchlorosilane, diethylisopropylchlorosilane, dimethylisopropylchlorosilane, tributylchlorosilane, triisobutylchlorosilane, triphenylchlorosilane, and tribenzylchlorosilane; the benzene solvent is toluene.

[0015] Still further, the molar ratio of the sum of the molar amounts of 4,4'-difluorobenzophenone and the difluoro monomer with a silicon-containing side chain to hydroquinone is 1:1;

[0016] The dosage of the difluoro monomer with a silicon-containing side chain accounts for 10% - 40% of the sum of the molar amounts of 4,4'-difluorobenzophenone and the difluoro monomer with a silicon-containing side chain.

[0017] Still further, the salifying agent is sodium carbonate and / or potassium carbonate, and the dosage of the salifying agent is 45% - 60% of the total molar amount of hydroquinone, 4,4'-difluorobenzophenone, and the difluoro monomer with a silicon-containing side chain.

[0018] Furthermore, the solvent is diphenyl sulfone; the molar proportion of the solvent in the reaction system is 55%-70%.

[0019] Furthermore, the process of heating and dissolving until no bubbles are generated is: first heating to a temperature within the range of 120-200° C. to completely dissolve the solvent, then heating to 200-250° C. and keeping the temperature for a pre-reaction of 1-4 hours.

[0020] Further, the copolymerization condensation reaction temperature is in the range of 280-315°C, and the reaction time is in the range of 5-8h. Preferably, the copolymerization condensation reaction temperature is 300-310°C, and the reaction time is 6-7h.

[0021] Another aspect of the present invention provides an atomic oxygen resistant polyetheretherketone material for aviation prepared by the above method, which has the following chemical structure:

[0022]

[0023] Wherein x and y are the degree of polymerization, the value of x is 30-100, the value of y is 170-240, and the number average molecular weight of the polymer is 80,000 to 110,000 g / mol.

[0024] The last aspect of the present invention provides a composite material, comprising the atomic oxygen-resistant polyetheretherketone material for aviation prepared by the above method and a filler, wherein the filler accounts for at least 1wt% in the composite material;

[0025] Furthermore, the filler is selected from one or more of metal oxides, metal chlorides, metal carbides, and non-metal carbides. The filler is preferably one or more of chromium chloride, zirconium carbide (ZrC), and boron carbide.

[0026] Beneficial technical effects:

[0027] The present invention obtains polyetheretherketone with a special functional group of silicon element in the side chain at the front end of synthesis by a chemical modification method. When the polymer of the present invention is irradiated with atomic oxygen, the silicon element reacts with the atomic oxygen to generate an inorganic silicon oxide layer in situ on the surface of the polymer material, thereby achieving the effect of inhibiting further erosion of the material surface by atomic oxygen. The polymer has high resistance to atomic oxygen and shows good self-repairing properties, and is suitable for the field of new material technology used in low earth orbit. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The surface morphology of the pure polyetheretherketone sample of Comparative Example 1 before and after atomic oxygen treatment is shown in electron microscope images;

[0029] Figure 2 This is an electron microscope image of the surface morphology of the polyetheretherketone sample containing silicon in the side chain of Example 1 after being treated with atomic oxygen;

[0030] Figure 3 This is an electron microscope image of the surface morphology of the polyetheretherketone sample containing silicon in the side chain of Example 2 after being treated with atomic oxygen;

[0031] Figure 4 This is an electron micrograph of the surface morphology of the polyetheretherketone sample containing silicon in the side chain of Example 3 after being treated with atomic oxygen;

[0032] Figure 5 This is an electron microscope image of the surface morphology of the composite material sample of polyetheretherketone containing silicon in the side chain and 10 wt% chromium chloride after being treated with atomic oxygen in Example 4. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present invention will be described clearly and completely below in combination with the embodiments of the present invention and the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. All other embodiments obtained by ordinary technicians in this field without creative work based on the embodiments of the present invention are within the scope of protection of the present invention.

[0034] Unless otherwise specifically stated, the numerical value set forth in these embodiments does not limit the scope of the present invention. The technology and method known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology and method should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values.

[0035] The experimental methods in the following examples without specifying specific conditions are usually measured in accordance with national standards; if there is no corresponding national standard, the method is carried out in accordance with the general standard requirements or general methods.

[0036] Preparation Example 1

[0037] This case is the synthesis of a difluoro monomer containing a silicon side chain:

[0038] Under nitrogen protection, 50 ml of toluene was added to a three-necked flask, followed by 22.02 g of 4,4'-difluorobenzhydrol. The temperature was controlled at 45°C. After 4,4'-difluorobenzhydrol was completely dissolved, an excess of 20 g of trimethylsilyl chloride was slowly added using a constant pressure dropping funnel. After reacting for 2 hours, the temperature was raised to 105°C to evaporate the solvent and excess trimethylsilyl chloride, and then cooled and crystallized to obtain a difluoro monomer containing a silicon side chain (represented as monomer A in the following examples). The reaction equation is as follows:

[0039]

[0040] The purity of the obtained monomer A was analyzed by liquid chromatography, with acetonitrile as the mobile phase. The liquid chromatography showed that the purity of the difluoromonomer containing silicon side chains obtained by the above method was 99.5%, and there was basically no impurity. The obtained monomer A was also tested by infrared spectroscopy. At the wave number of 3550cm -1 No corresponding OH vibration absorption peak was observed nearby. -1 The characteristic absorption peak of Si-O appeared at , which indicates that the above-mentioned difluoro monomer containing silicon side chain was successfully synthesized.

[0041] Example 1

[0042] A method for preparing an atomic oxygen-resistant polyetheretherketone material for aviation, comprising the following steps:

[0043] Under nitrogen atmosphere, 200g of diphenyl sulfone solvent, 22.06g of sodium carbonate, and 22.022g of hydroquinone were added to a 500mL three-necked flask with mechanical stirring, and the temperature was gradually raised to 140°C. After the solvent was completely melted, the temperature was raised to 240°C and kept warm for 2h until no bubbles were generated. Then 39.276g of 4,4'-difluorobenzophenone and 5.828g of monomer A were added to form a reaction system, and the temperature was continued to rise to 308°C. The copolymerization condensation reaction was carried out at this temperature for 6 hours and the reaction was terminated. The reaction solution was poured into water to precipitate the product, and then the polyetheretherketone (number average molecular weight of 80,000 to 110,000 g / mol) containing silicon elements in the side chain was prepared through washing, drying, crushing and other processes, and the atomic oxygen resistant polyetheretherketone material for aviation was obtained.

[0044] Example 2

[0045] A method for preparing an atomic oxygen-resistant polyetheretherketone material for aviation, comprising the following steps:

[0046] Under nitrogen atmosphere, 200g diphenyl sulfone solvent, 22.06g sodium carbonate, and 22.022g hydroquinone were added to a 500mL three-necked flask with mechanical stirring, and the temperature was gradually raised to 140°C. After the solvent was completely melted, the temperature was raised to 240°C and kept warm for 2h until no bubbles were generated. Then 34.912g 4,4'-difluorobenzophenone and 11.656g monomer A were added to form a reaction system, and the temperature was continued to rise to 308°C. The copolymerization condensation reaction was carried out at this temperature for 6 hours and the reaction was terminated. The reaction solution was poured into water to precipitate the product, and then the polyetheretherketone with silicon element in the side chain (number average molecular weight of 80,000 to 110,000 g / mol) was prepared through washing, drying, crushing and other processes, that is, the atomic oxygen resistant polyetheretherketone material for aviation was obtained.

[0047] Example 3

[0048] A method for preparing an atomic oxygen-resistant polyetheretherketone material for aviation, comprising the following steps:

[0049] Under nitrogen atmosphere, 200g diphenyl sulfone solvent, 22.06g sodium carbonate, and 22.022g hydroquinone were added to a 500mL three-necked flask with mechanical stirring, and the temperature was gradually raised to 140°C. After the solvent was completely melted, the temperature was raised to 240°C and kept warm for 2h until no bubbles were generated. Then 26.184g 4,4'-difluorobenzophenone and 23.311g monomer A were added to form a reaction system, and the temperature was continued to rise to 308°C. The copolymerization condensation reaction was carried out at this temperature for 6 hours and the reaction was terminated. The reaction solution was poured into water to precipitate the product, and then the polyetheretherketone (number average molecular weight of 80,000 to 110,000 g / mol) containing silicon elements in the side chain was prepared through washing, drying, crushing and other processes, and the atomic oxygen resistant polyetheretherketone material for aviation was obtained.

[0050] Example 4

[0051] The chromium chloride powder (particle size less than 200 nm) was treated by KH570 wet method, and the treated chromium chloride was melt-blended and extruded with the polyetheretherketone containing silicon in the side chain of Example 3 at 370-390° C. to obtain a composite material (chromium chloride accounted for 10 wt % in the composite material).

[0052] Comparative Example 1

[0053] Under nitrogen atmosphere, 200g of diphenyl sulfone solvent, 22.06g of sodium carbonate, and 22.022g of hydroquinone were added to a 500mL three-necked flask with mechanical stirring, and the temperature was gradually raised to 140°C. After the solvent was completely melted, the temperature was raised to 240°C. After the system reacted for 2h, 43.64g of 4,4'-difluorobenzophenone was added, and the temperature was continued to rise to 308°C. After reacting at this temperature for 6 hours, the reaction was terminated. The reaction solution was poured into water to precipitate the product, and then pure polyetheretherketone was prepared through washing, drying, crushing and other processes.

[0054] The performance tests were performed on the materials of the above embodiments and comparative examples, and the results are shown in Table 1.

[0055] The ground atomic oxygen simulation equipment was used to calibrate the cumulative atomic oxygen flux by the mass loss of the standard Kapton. The test sample was a 20×20×1mm molded sample.

[0056] Erosion rate Where △M is the lost mass g, F is the cumulative atomic oxygen flux atoms / cm 2 , A sample area cm 2 ,ρ sample density g / cm 3 , * represents the multiplication sign.

[0057] Table 1 Material properties of each case

[0058]

[0059] The SEM images of the samples of Comparative Example 1 and Examples 1-3 before and after the atomic oxygen test are as follows: Figure 1-4 As shown in Table 1, the electron microscopy image of the pure polyetheretherketone sample of Comparative Example 1 before atomic oxygen treatment is as follows: Figure 1 As shown in the left figure, the surface is relatively smooth; the electron microscope image of the pure polyetheretherketone sample after atomic oxygen treatment is as follows Figure 1 As shown in the right figure, the surface is relatively rough and has many micro-nanopores. Example 1 The electron microscope image of the polyetheretherketone sample containing silicon in the side chain after atomic oxygen treatment is as follows Figure 2 As shown in Figure 2, the surface is relatively rough and has more micro-nano pores, but the pores are obviously larger than Figure 1 The right figure shows that the pores are small, and the atomic oxygen erosion rate of polyetheretherketone containing silicon elements in the side chain is reduced by 14.6% compared with pure PEEK, and the atomic oxygen resistance is improved by 11.9% (calculated by mass loss). Example 2 The electron microscope image of the polyetheretherketone sample containing silicon elements in the side chain after atomic oxygen treatment is as follows Figure 3 As shown, the surface is slightly rough, with only a few holes on the sample surface. The atomic oxygen erosion rate of polyetheretherketone containing silicon elements in the side chain is reduced by 41.6% compared with pure PEEK, and the atomic oxygen resistance is improved by 39.7%. Example 3 The electron microscope image of the polyetheretherketone sample containing silicon elements in the side chain after atomic oxygen treatment is as follows Figure 4 As shown, the surface is relatively rough, but there are basically no holes on the sample surface. The atomic oxygen erosion rate of polyetheretherketone containing silicon in the side chain is reduced by 76.9% compared with pure PEEK, and the atomic oxygen resistance is increased by 76.1%. This is because a dense inorganic silicon oxide layer is formed on the surface, which can well protect the internal polyetheretherketone resin from the erosion of external atomic oxygen. Example 4 shows that the atomic oxygen resistance of the composite material of 10% chromium chloride and polyetheretherketone containing silicon in the side chain is further improved. The electron microscope image of the sample after atomic oxygen treatment is as follows: Figure 5 As shown, it can be seen that a dense protective layer is formed on the surface of the sample. The atomic oxygen erosion resistance of the composite material is reduced by 96.1% compared with pure PEEK, and the atomic oxygen resistance is increased by 95.8%. This is mainly because the synergistic effect of silicon oxide and chromium oxide formed on the surface of the material greatly improves the atomic oxygen resistance of the material.

[0060] From the above data, it can be inferred that: with the increase of the content of silicon-containing functional groups in the side chain of polyetheretherketone molecules, the atomic oxygen resistance of the product is significantly improved; at the same time, the synergistic effect of the characteristic metal elements chromium and silicon can greatly improve the atomic oxygen resistance of the composite material.

[0061] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing an atomic oxygen-resistant polyetheretherketone material for aviation, characterized in that: The steps include: A part of fluoroketone raw materials is replaced by difluoro monomers containing silicon side chains, and atomic oxygen resistant polyetheretherketone materials for aviation are obtained through copolymerization and condensation.

2. The method for preparing an atomic oxygen resistant polyetheretherketone material for aviation use according to claim 1, characterized in that: The specific steps include: Under a protective atmosphere, hydroquinone and a salt-forming agent are placed in a solvent and heated to dissolve until no bubbles are generated. 4,4'-difluorobenzophenone and a difluoro monomer containing a silicon side chain are added to form a reaction system. The temperature is continued to be raised to carry out a copolymerization condensation reaction. After the reaction is completed, the product is precipitated with water to obtain an atomic oxygen-resistant polyetheretherketone material for aviation use.

3. The method for preparing an atomic oxygen resistant polyetheretherketone material for aviation use according to claim 2, characterized in that: The chemical structure of the difluoro monomer containing a silicon side chain is as follows: Wherein R1, R2, and R3 are selected from the same alkyl, phenyl, and benzyl groups, or R1, R2, and R3 are all selected from alkyl groups and two of them are the same alkyl group, and the alkyl group is a normal or isomeric alkyl group having less than 5 carbon atoms.

4. The method for preparing an atomic oxygen resistant polyetheretherketone material for aviation use according to claim 3, characterized in that: The difluoro monomer containing silicon side chains is obtained by the following method: under a protective atmosphere, difluorobenzhydrol is added to a benzene solvent, after being completely dissolved, an excess amount of chlorosilane is added in a molar ratio, the mixture is reacted at a temperature below 60° C. for 1-2 hours, the temperature is raised to above 100° C. to evaporate the benzene solvent and unreacted chlorosilane, and the difluoro monomer containing silicon side chains is obtained by cooling and crystallization.

5. The method for preparing an atomic oxygen resistant polyetheretherketone material for aviation use according to claim 3, characterized in that: The chlorosilane is selected from one of trimethylchlorosilane, triethylchlorosilane, tri-n-propylchlorosilane, triisopropylchlorosilane, diethylisopropylchlorosilane, dimethylisopropylchlorosilane, tributylchlorosilane, triisobutylchlorosilane, triphenylchlorosilane and tribenzylchlorosilane; and the benzene solvent is toluene.

6. The method for preparing an atomic oxygen resistant polyetheretherketone material for aviation use according to claim 3, characterized in that: The molar ratio of the sum of the molar amounts of the 4,4'-difluorobenzophenone and the difluoro monomer containing a silicon side chain to the molar amount of the hydroquinone is 1:1; The amount of the difluoromonomer containing a silicon side chain is 10% to 40% of the sum of the molar amounts of the 4,4'-difluorobenzophenone and the difluoromonomer containing a silicon side chain.

7. The method for preparing an atomic oxygen resistant polyetheretherketone material for aviation use according to claim 3, characterized in that: The salt-forming agent is sodium carbonate and / or potassium carbonate, and the amount of the salt-forming agent is 45%-60% of the total molar amount of the hydroquinone, the 4,4'-difluorobenzophenone and the difluoro monomer containing a silicon side chain; The solvent is diphenyl sulfone; the molar proportion of the solvent in the reaction system is 55%-70%.

8. The method for preparing an atomic oxygen resistant polyetheretherketone material for aviation use according to claim 3, characterized in that: The process of heating and dissolving until no bubbles are generated is: firstly heating to a temperature within a range of 120-200° C. to completely dissolve the solvent, then heating to 200-250° C. and keeping the temperature for a pre-reaction of 1-4 hours; The copolymerization condensation reaction temperature is in the range of 280-315° C., and the reaction time is in the range of 5-8 hours.

9. The atomic oxygen resistant polyetheretherketone material for aviation obtained by the preparation method according to any one of claims 1 to 8, characterized in that: The specific chemical structure is as follows: Wherein x and y are the degree of polymerization, the value of x is 30-100, the value of y is 170-240, and the number average molecular weight of the polymer is 80,000 to 110,000 g / mol.

10. A composite material, characterized in that: The invention comprises an atomic oxygen resistant polyetheretherketone material for aviation obtained by the preparation method according to any one of claims 1 to 8 and a filler, wherein the filler accounts for at least 1wt% of the composite material.

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