A polyetheretherketone-based composite material resistant to high and low temperature friction

Abstract

The present invention relates to the technical field of polyetheretherketone composite materials, and specifically relates to a polyetheretherketone-based composite material resistant to high and low temperature friction, which is formed by melt blending a polyetheretherketone matrix material and a bimetal-nitrogen-doped carbon nanoalloy material; by nitriding a zeolitic imidazolate framework structure material to form framework carbon nitride, and then loading a bimetal to form a nanoalloy material; the composite material of the present invention has a lower surface energy, excellent chemical stability, strong mechanical strength, high temperature resistance, excellent wear resistance and lubricity; when used under conditions of high temperature, high pressure, high load and special corrosive gases, the friction coefficient and the volume wear amount are small, the friction life is long, and it has good thermal stability and chemical stability.

Description

Technical Field

[0001] The present invention relates to the technical field of polyetheretherketone composite materials, and particularly relates to a polyetheretherketone-based composite material with high and low temperature friction resistance. Background Art

[0002] Polyetheretherketone is a thermoplastic polymer material with high mechanical strength, high temperature resistance, impact resistance, flame retardancy, acid and alkali resistance, hydrolysis resistance, wear resistance, fatigue resistance, radiation resistance and good electrical properties, and has a large number of applications in the fields of aerospace, medical devices and industry. In order to be suitable for different working environments, the modification of polyetheretherketone has always been a hot topic.

[0003] Although it has many advantages, there are still some defects and deficiencies in friction modification. The existing wear-resistant modified materials of polyetheretherketone generally include carbon fiber, graphite and polytetrafluoroethylene. The wear characteristics of graphite depend on gas adsorption, and its lubrication performance is greatly reduced under dry or humid high-temperature conditions, resulting in a decline in the performance of the composite material. The thermal decomposition products of polytetrafluoroethylene increase with the increase of temperature, and the content and toxicity also increase. The interfacial bonding performance is insufficient. For the PEEK composite materials prepared by filling modification and blending modification, there is often a problem of insufficient interfacial bonding performance. This will lead to a decline in some properties of the composite material, especially the mechanical properties and friction properties may not meet the expectations. The embrittlement temperature of polyetheretherketone is below -140°C, which means that it can maintain certain mechanical properties and physical properties below this temperature. However, under ultra-low temperature conditions, due to embrittlement, the wear resistance is severely affected. Summary of the Invention

[0004] In order to solve the technical problem of the decline in the friction performance of PEEK under extreme working conditions, a polyetheretherketone-based composite material with high and low temperature friction resistance is provided. The composite material of the present invention has good friction resistance under ultra-high temperature, ultra-low temperature, high speed and high load conditions.

[0005] In order to achieve the above purpose, the present invention is realized through the following technical solutions:

[0006] A polyetheretherketone-based composite material with high and low temperature friction resistance, which is formed by melt blending a polyetheretherketone matrix material and a bimetal-nitrogen-doped carbon nanoalloy material;

[0007] The dosage of the bimetal-nitrogen-doped carbon nanoalloy material is 1-15 wt% of the polyetheretherketone matrix material.

[0008] Further, the bimetal-nitrogen-doped carbon nanoalloy material is obtained by: doping nitrogen into a zeolitic imidazolate framework material to form framework carbon nitride, and then loading bimetals to form a nanoalloy material.

[0009] Further, the preparation of the bimetallic-nitrogen-doped carbon nanoalloy material specifically includes the following steps:

[0010] S1. Calcinate the zeolitic imidazolate framework material in a nitrogen atmosphere at 1000 - 1500 °C to obtain framework nitrogen-doped carbon;

[0011] S2. Wet-mix two different metal salts with the framework nitrogen-doped carbon, dry and grind, calcinate in a nitrogen atmosphere at 800 - 1500 °C, subject the calcined product to dilute acid treatment, wash until neutral and then dry, and anneal again in a nitrogen atmosphere at 900 - 1200 °C to obtain the bimetallic-nitrogen-doped carbon nanoalloy material, where the total bimetallic loading ranges from 5 - 20 wt%.

[0012] Preferably, the zeolitic imidazolate framework material is a coordination compound of zinc ions and imidazole, with an average particle size of 200 - 300 nm, a specific surface area of more than 2000 m 2 / g, an average pore diameter of 0.3 - 0.8 nm, and a porosity of 20 - 50%;

[0013] The anions in the metal salts are selected from acetylacetonate, nitrate, and chloride, and the metal cations are selected from transition metal elements. Preferably, the transition metal elements are two of iron, cobalt, nickel, chromium, manganese, titanium, copper, molybdenum, and silver.

[0014] More preferably, the metal salt is selected from one of the combinations of iron acetylacetonate and cobalt nitrate, or chromium nitrate and manganese acetylacetonate, or nickel acetylacetonate and molybdenum disulfide;

[0015] If the metal salt is selected as the combination of iron acetylacetonate and cobalt nitrate, the mass ratio of the framework nitrogen-doped carbon, iron acetylacetonate, and cobalt nitrate is 5:1:1;

[0016] If the metal salt is selected as the combination of chromium nitrate and manganese acetylacetonate, the mass ratio of the framework nitrogen-doped carbon, chromium nitrate, and manganese acetylacetonate is 5:2:1;

[0017] If the metal salt is selected as the combination of nickel acetylacetonate and molybdenum disulfide, the mass ratio of the framework nitrogen-doped carbon, nickel acetylacetonate, and molybdenum disulfide is 5:1:2.

[0018] Preferably, the heat preservation time for calcination in S1 at 1000 - 1500 °C is 2 - 5 h; the heat preservation time for calcination in S2 at 800 - 1500 °C is 1 - 3 h; the heat preservation time for annealing treatment in S2 at 900 - 1200 °C is 1 - 3 h;

[0019] In S2, the dilute acid treatment uses a hydrochloric acid solution with a concentration lower than 0.5 M for impurity removal for 6 - 48 h;

[0020] The wet mixing described in S2 is to ultrasonically disperse metal salts in an alcohol solvent. After ultrasonic dispersion for 1 - 2 h, the solvent is evaporated.

[0021] Furthermore, the extrusion temperature of the twin - screw extruder used for melt blending is 360 - 380 °C, and the rotation speed is 150 - 250 rpm.

[0022] Beneficial technical effects:

[0023] In the present invention, by doping nitrogen into ZIFs and then loading any one combination of FeCo, CrMn, and NiMo bimetals, a bimetal - nitrogen - doped carbon nano - alloy material is formed. After being compounded with polyether ether ketone, the nanoparticles can be uniformly dispersed in the matrix, forming a uniform microstructure. And the addition of multiple elements significantly increases the entropy value and embrittlement temperature of the composite material, enabling the composite material to have good overall wear resistance under ultra - high temperature, ultra - low temperature, high - speed, and high - load conditions;

[0024] The composite material of the present invention has a lower surface energy, excellent chemical stability, strong mechanical strength, high heat resistance, excellent wear resistance and lubricity; when used under high - temperature, high - pressure, high - load and special corrosive gas conditions, it has a small friction coefficient and volume wear, a long friction life, and good thermal stability and chemical stability, and is superior to carbon fiber, graphite, polytetrafluoroethylene and other modified PEEKs in high - and low - temperature wear resistance tests. Specific embodiments

[0025] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way restricts the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0026] Unless otherwise specifically stated, the numerical values set forth in these embodiments do not limit the scope of the present invention. Technologies and methods known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such technologies and methods should be regarded as part of the specification. In all the examples shown and discussed here, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values.

[0027] The experimental methods without specific conditions noted in the following embodiments are generally determined according to national standards; if there are no corresponding national standards, they are carried out according to general standard requirements or general methods.

[0028] Preparation Example 1

[0029] Preparation of ZIFs:

[0030] Dissolve 17.88 g of zinc nitrate in 200 mL of ethanol, and dissolve 18.48 g of 4-methylimidazole in another portion of ethanol of the same volume. After the two are dissolved separately, mix them and stir at high speed at 60 °C for 24 h. Then, after centrifugation, washing, and drying, white powdery ZIFs are obtained.

[0031] The particle size and BET of the ZIFs in this case were tested. The particle size was 220 nm, the pore size was 0.6 nm, the specific surface area was 2464 m 2 / g, and the porosity was 24%.

[0032] Example 1

[0033] Preparation of bimetallic-nitrogen-doped carbon nanoalloy material:

[0034] S1. Place the ZIFs of Preparation Example 1 in a tubular furnace, heat it to 1200 °C at a heating rate of 5 °C / min under a nitrogen atmosphere, keep the temperature for 3 h, and then naturally cool to obtain skeleton nitrogen-doped carbon in the form of black powder;

[0035] S2. Disperse 50 g of iron acetylacetonate, 50 g of cobalt nitrate, and 250 g of the skeleton nitrogen-doped carbon in anhydrous ethanol, ultrasonically disperse for 1 h, evaporate the solvent and grind, then place it in a nitrogen atmosphere and heat it to 1200 °C at a heating rate of 5 °C / min, keep the temperature for 2 h; Use 0.1 M dilute hydrochloric acid solution to remove impurities from the calcined product for 24 h, then wash it with deionized water until neutral and dry it at 80 °C, and then place it in a nitrogen atmosphere again and heat it to 1000 °C at a heating rate of 5 °C / min for annealing treatment for 2 h to obtain FeCo-nitrogen-doped carbon nanoalloy material.

[0036] In the FeCo-nitrogen-doped carbon nanoalloy material of this case, the Fe loading is 7 wt% and the Co loading is 8 wt%.

[0037] A polyetheretherketone-based composite material resistant to high and low temperature friction. 500 g of the FeCo-nitrogen-doped carbon nanoalloy material in this example and 4500 g of PEEK coarse powder were mixed evenly using a mixer (process: power 10 KW, mixing time 20 min). The obtained mixture was extruded and pelletized using a conical twin-screw extruder. The temperatures of each section of the extruder were 365 °C, 365 °C, 370 °C, 370 °C, 370 °C, 370 °C, and the rotation speed was set at 200 r / min. Then, it was injection-molded using a servo electric injection molding machine. The process temperature was 380 °C, 375 °C, 375 °C, 375 °C, and the temperature of the mold was set at 160 - 180 °C to obtain a molded part of the polyetheretherketone-based composite material resistant to high and low temperature friction.

[0038] Example 2

[0039] Preparation of the bimetal-nitrogen-doped carbon nanoalloy material:

[0040] S1. Place the ZIFs of Preparation Example 1 in a tubular furnace, heat it up to 1000 °C at a heating rate of 3 °C / min under a nitrogen atmosphere, keep it for 5 h, and then cool it naturally to obtain black powder of skeleton nitrogen-doped carbon.

[0041] S2. Disperse 100 g of chromium nitrate, 50 g of manganese acetylacetonate, and 250 g of the skeleton nitrogen-doped carbon in absolute ethanol, ultrasonically disperse for 2 h, evaporate the solvent and grind, then place it in a nitrogen atmosphere and heat it up to 1200 °C at a heating rate of 10 °C / min, keep it for 2 h; use 0.1 M dilute hydrochloric acid solution to remove impurities from the calcined product for 24 h, then wash it with deionized water until neutral and dry it at 80 °C, and then place it in a nitrogen atmosphere again and heat it up to 900 °C at a heating rate of 10 °C / min for annealing treatment for 2 h to obtain the CrMn-nitrogen-doped carbon nanoalloy material.

[0042] In the CrMn-nitrogen-doped carbon nanoalloy material of this example, the Cr loading is 9 wt% and the Mn loading is 5 wt%.

[0043] A polyetheretherketone-based composite material resistant to high and low temperature friction. 500 g of the CrMn-nitrogen-doped carbon nanoalloy material in this example and 4500 g of PEEK coarse powder were mixed evenly using a mixer (process: power 5 KW, mixing time 40 min). The obtained mixture was extruded and pelletized using a conical twin-screw extruder. The temperatures of each section of the extruder were 365 °C, 365 °C, 370 °C, 370 °C, 370 °C, 370 °C, and the rotation speed was set at 250 r / min. Then, it was injection-molded using a servo electric injection molding machine. The process temperature was 380 °C, 375 °C, 375 °C, 375 °C, and the temperature of the mold was set at 160 - 180 °C to obtain a molded part of the polyetheretherketone-based composite material resistant to high and low temperature friction.

[0044] Example 3

[0045] Preparation of Bimetallic-Nitrogen-Doped Carbon Nanocomposite Material:

[0046] S1. Place the ZIFs of Preparation Example 1 in a tube furnace, heat it up to 1500 °C at a heating rate of 10 °C / min under a nitrogen atmosphere, keep it at this temperature for 3 h, and then cool it naturally to obtain black powder of skeleton nitrogen-doped carbon;

[0047] S2. Disperse 50 g of nickel acetylacetonate, 100 g of molybdenum disulfide and 250 g of the skeleton nitrogen-doped carbon in absolute ethanol, ultrasonically disperse for 2 h, evaporate the solvent and grind, then place it in a nitrogen atmosphere and heat it up to 1500 °C at a heating rate of 3 °C / min, keep it at this temperature for 2 h; Use 0.1 M dilute hydrochloric acid solution to remove impurities from the calcined product for 24 h, then wash it with deionized water until neutral and dry it at 80 °C, and then place it in a nitrogen atmosphere again and heat it up to 1200 °C at a heating rate of 10 °C / min for annealing treatment for 2 h to obtain NiMo-nitrogen-doped carbon nanocomposite material.

[0048] In the NiMo-nitrogen-doped carbon nanocomposite material of this example, the Ni loading is 4 wt% and the Mo loading is 14 wt%.

[0049] A polyetheretherketone-based composite material resistant to high and low temperature friction. Mix 500 g of the NiMo-nitrogen-doped carbon nanocomposite material of this example and 4500 g of PEEK coarse powder evenly by a mixer (process: power is 2 KW, mixing time is 50 min). Extrude and pelletize the obtained mixture by a conical twin-screw extruder. The temperatures of each section of the extruder are 365 °C, 365 °C, 370 °C, 370 °C, 370 °C, 370 °C, and the rotation speed is set to 200 r / min. Then, use a servo electric injection molding machine for injection molding. The process temperature is 380 °C, 375 °C, 375 °C, 375 °C, and the temperature of the mold is set to 160 - 180 °C to obtain a molded part of the polyetheretherketone-based composite material resistant to high and low temperature friction.

[0050] Comparative Example 1

[0051] The composite material of this example is composed of 10 wt% short carbon fiber and 90 wt% PEEK coarse powder by melt blending (the melt blending process is the same as that in Example 1).

[0052] Comparative Example 2

[0053] The composite material of this example is composed of 10 wt% skeleton nitrogen-doped carbon (the product of S1 in Example 1) and 90 wt% PEEK coarse powder by melt blending (the melt blending process is the same as that in Example 1).

[0054] Comparative Example 3

[0055] The composite material in this case is composed of 10 wt% ZIFs (the product of Preparation Example 1) and 90 wt% PEEK coarse powder by melt blending (the melt blending process is the same as that in Example 1).

[0056] Comparative Example 4

[0057] The composite material in this case is composed of Fe, Co (calcined after uniformly mixing iron acetylacetonate and cobalt nitrate) and PEEK coarse powder by melt blending (the proportion of the two metals is the same as that in Example 1, and the melt blending process is the same as that in Example 1).

[0058] Test Example

[0059] Test 1: The injection-molded friction parts obtained are ground against 316L steel friction counterparts for 24 h. The process of the friction and wear machine is 500 N / 2000 rpm. The average friction coefficient and volume wear rate are shown in Table 1.

[0060] Test 2: The injection-molded friction parts obtained are ground against 316L steel friction counterparts at a high temperature of 260 °C for 24 h. The process of the friction and wear machine is 500 N / 2000 rpm. The average friction coefficient and volume wear rate are shown in Table 1.

[0061] Test 3: The injection-molded friction parts obtained are ground against 316L steel friction counterparts at a high temperature of 300 °C for 24 h. The process of the friction and wear machine is 800 N / 3000 rpm. The average friction coefficient and volume wear rate are shown in Table 1.

[0062] Test 4: The injection-molded friction parts obtained are ground against 316L steel friction counterparts at a high temperature of -100 °C for 24 h. The process of the friction and wear machine is 500 N / 2000 rpm. The average friction coefficient and volume wear rate are shown in Table 1.

[0063] Test 5: The injection-molded friction parts obtained are ground against 316L steel friction counterparts at a high temperature of -150 °C for 24 h. The process of the friction and wear machine is 500 N / 2000 rpm. The average friction coefficient and volume wear rate are shown in Table 1.

[0064] Test 6: The injection-molded friction parts obtained are ground against 316L steel friction counterparts at a high temperature of -200 °C for 24 h. The process of the friction and wear machine is 500 N / 2000 rpm. The average friction coefficient and volume wear rate are shown in Table 1.

[0065] Table 1 Friction Performance of Composite Materials at High and Low Temperatures

[0066]

[0067] (Note: μ represents the average friction coefficient; I represents the volume wear rate; the test standard is ASTM-G137)

[0068] As can be seen from Table 1, when using ZIFs structure, bimetallic oxides, nitrogen-doped carbon, and carbon fiber alone to modify PEEK, the wear resistance effect is not significant. The present invention adopts a bimetallic-nitrogen-doped carbon nanoalloy material. Due to its small size and large surface atom ratio, its surface energy is relatively high, making it prone to surface reconstruction and self-repair phenomena. The nano effect enables it to exhibit higher wear resistance during the friction process; and due to the presence of the carrier skeleton nitrogen-doped carbon, the bimetallic nanoparticles can be evenly dispersed in the matrix, forming a uniform microstructure, which helps to improve the overall wear resistance of the material and makes its performance superior to that of PEEK modified with graphite, polytetrafluoroethylene, and carbon fiber under ultra-high temperature, ultra-low temperature, high-speed, and high-load conditions, and the preparation cost is low.

[0069] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its inventive concept, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A polyetheretherketone-based composite material resistant to high and low temperature friction, characterized in that: It comprises a polyetheretherketone matrix material and a bimetallic-nitrogen-doped carbon nano alloy material which are melt-blended; The preparation of the bimetallic-nitrogen doped carbon nano alloy material specifically comprises the following steps: S1, calcining the zeolite imidazolate framework material at 1000-1500° C. in a nitrogen atmosphere to obtain framework nitrogen-doped carbon; The zeolite imidazolate skeleton structure material is a coordination compound of zinc ion and imidazole, with an average particle size of 200-300nm and a specific surface area of ​​2000m 2 / g or more, average pore size 0.3-0.8nm, porosity 20-50%; S2, wet-mixing two different metal salts with the skeleton nitrogen-doped carbon, grinding after drying, calcining at 800-1500° C. in a nitrogen atmosphere, treating the calcined product with dilute acid, washing to neutrality and drying, and annealing again at 900-1200° C. in a nitrogen atmosphere to obtain a bimetallic-nitrogen-doped carbon nanoalloy material, wherein the total bimetal loading ranges from 5 to 20 wt%; The metal salt is selected from a combination of iron acetylacetonate and cobalt nitrate, a combination of chromium nitrate and manganese acetylacetonate, or a combination of nickel acetylacetonate and molybdenum disulfide; If the metal salt is a combination of ferric acetylacetonate and cobalt nitrate, the mass ratio of the framework nitrogen-doped carbon, ferric acetylacetonate, and cobalt nitrate is 5:1:1; If the metal salt is a combination of chromium nitrate and manganese acetylacetonate, the mass ratio of the framework nitrogen-doped carbon, chromium nitrate, and manganese acetylacetonate is 5:2:1; If the metal salt is a combination of nickel acetylacetonate and molybdenum disulfide, the mass ratio of the framework nitrogen-doped carbon, nickel acetylacetonate, and molybdenum disulfide is 5:1:2; The twin-screw extruder used in the melt blending has an extrusion temperature of 360-380° C. and a rotation speed of 150-250 rpm; The amount of the bimetallic-nitrogen doped carbon nano alloy material is 1-15wt% of the polyetheretherketone matrix material.

2. A polyetheretherketone-based composite material resistant to high and low temperature friction according to claim 1, characterized in that: The holding time of calcination at 1000-1500°C in S1 is 2-5h; the holding time of calcination at 800-1500°C in S2 is 1-3h; the holding time of annealing at 900-1200°C in S2 is 1-3h; The dilute acid treatment in S2 uses a hydrochloric acid solution below 0.5M to remove impurities for 6-48 hours; The wet mixing described in S2 is to ultrasonically disperse the metal salt in the alcohol solvent, and after ultrasonic dispersion for 1-2 hours, evaporate the solvent.

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