High-strength wear-resistant composite special plastic and preparation method thereof

Abstract

The invention discloses a high-strength wear-resistant composite special plastic and a preparation method thereof in the technical field of special plastics. The high-strength wear-resistant composite special plastic comprises the following components in parts by weight: 8-10 parts of a modified first monomer, 1.5-2 parts of a second monomer, 0.25-0.9 part of a soft segment compound, 5-7.5 parts of a metal salt compound and 2.8-4.5 parts of polytetrafluoroethylene powder. A PEEK synthetic monomer is modified to improve the reaction activity of PEEK matrix polymerization, meanwhile, a small amount of soft segment chains containing ether bonds are introduced into a PEEK-based polymerization molecular chain to improve the self-lubricating capacity of PEEK, a high-stability PEEK matrix material is formed through doping of metal ions, and a PEEK / PTFE composite form is adopted to improve the self-lubricating capacity of PEEK. The PEEK-based composite special plastic with high strength, high toughness, low friction coefficient and low wear rate is realized, and the PEEK-based composite special plastic has remarkable antifriction and wear-resistant effects in heavy-load, high-speed and high-temperature friction occasions.

Description

Technical Field

[0001] The present invention belongs to the technical field of special plastics, and specifically refers to a high-strength and wear-resistant composite special plastic and a preparation method thereof. Background Art

[0002] Special plastics are usually composed of a matrix material and a reinforcing material, aiming to enhance the mechanical properties, wear resistance, high-temperature resistance, and other specific functions of plastics by combining the advantages of both. The applications of such composite materials are extensive, covering industries such as aerospace, automotive, electronic equipment, and machinery manufacturing. By adding reinforcing fibers, fillers, or other high-performance materials, special plastics can significantly improve their mechanical strength and wear resistance. However, high-performance special plastics usually require expensive reinforcing materials (such as carbon fiber, glass fiber, etc.) and complex manufacturing processes, which result in their production costs being much higher than those of conventional plastics. Compared with traditional metal materials, special plastics have a lighter mass, which is particularly important in the aerospace and automotive industries. Although special plastics have relatively high strength, some types of composite materials may become brittle under high stress, especially in the absence of appropriate toughness enhancement. The processing technology of special plastics is relatively complex, especially in the production process, precise control of parameters such as temperature and pressure is required, otherwise it may affect the final performance of the material.

[0003] Special plastics are a type of high-performance materials formed by organically combining high-performance matrix resins with various reinforcing phases (such as glass fibers, carbon fibers, aramid fibers, inorganic particles, nanomaterials, or sandwich core materials). Their advantages lie in being able to balance multiple properties such as lightweight, high strength, wear resistance, chemical corrosion resistance, and customized functions. Taking glass fiber-reinforced plastic (GFRP) as an example, it has a relatively low cost, excellent electrical insulation and chemical resistance, and a mature molding process, but it has a relatively high density and average impact toughness; carbon fiber-reinforced plastic (CFRP) has extremely high specific strength and specific modulus, good fatigue and high-temperature resistance, and is suitable for the aerospace and high-end racing fields, but the raw materials and processing costs are extremely high, and additional treatment is required in insulating applications due to its conductivity; aramid (Kevlar)-reinforced plastic is famous for its excellent impact resistance and bulletproof performance, and has a low density and heat aging resistance, but the fibers are prone to moisture absorption, the processing and cutting costs are high, and it is sensitive to strong acid and strong base environments; inorganic particle or flake filler composite plastics (such as adding calcium carbonate, talcum powder, or glass microspheres) can significantly reduce costs, improve wear resistance or flame retardancy, and improve dimensional stability, but high contents are likely to increase the brittleness of the material and result in poor processing fluidity; in nanocomposite plastics, nanoreinforcing phases such as dispersed montmorillonite, carbon nanotubes, or graphene can significantly improve mechanical, thermal, and electrical properties at extremely low addition amounts, while endowing flame retardant or self-lubricating functions, but the nanoparticles are prone to agglomeration, and the dispersion difficulty and cost are relatively high; structural laminated / sandwich plastics sandwich lightweight foams or honeycomb core materials between high-strength surface layers to achieve excellent flexural stiffness-to-weight ratio and sound and heat insulation effects, but the preparation process is complex, interlayer delamination is likely to occur, and both repair and recycling are difficult; in addition, by physically blending or chemically copolymerizing multiple high-performance thermoplastic resins (such as PPS, PEEK, PEI, etc.), a blend or copolymer system with both high temperature resistance, flame retardancy, and excellent processability can be obtained, but the poor compatibility is prone to phase separation, and strict requirements are imposed on processing parameters. In summary, different types of special plastics have their own advantages and disadvantages. It is necessary to reasonably select the combination of matrix and reinforcing phase according to multiple factors such as performance requirements, cost and output, processing technology, use environment, and sustainable recycling in order to design a high-performance material that not only meets functional requirements but also has economic benefits. Summary of the Invention

[0004] In view of the above situation, to overcome the defects of the prior art, the present invention provides a high-strength wear-resistant composite special plastic and a preparation method thereof. The present invention modifies the PEEK synthesis monomer to improve the reaction activity of PEEK matrix polymerization. At the same time, a small amount of soft segment chains containing ether bonds are introduced into the PEEK-based polymer molecular chain to improve the self-lubricating ability of PEEK. Through the doping of metal ions, a highly stable PEEK matrix material is formed, and the form of PEEK / PTFE composite is adopted to realize a composite special plastic based on PEEK with high strength, high toughness, low friction coefficient and low wear rate, which has remarkable anti-friction and wear-resistant effects in heavy load, high-speed and high-temperature friction occasions.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows: The present invention provides a high-strength wear-resistant composite special plastic, and the preparation raw materials of the composite special plastic include the following components in parts by weight:

[0006] 7-10 parts of modified first monomer, 1.5-2 parts of second monomer, 0.25-0.9 part of soft segment compound, 5-7.5 parts of metal salt compound, 2.8-4.5 parts of polytetrafluoroethylene powder;

[0007] Preferably, the preparation raw materials of the modified first monomer include the following components in parts by weight: 3.0-9.2 parts of diamine compound, 7.2-8.3 parts of 4,4'-difluorobenzophenone, 3.5-5.5 parts of carbon disulfide, 2.0-2.8 parts of NaOH;

[0008] Preferably, the diamine compound includes at least one of p-phenylenediamine, m-phenylenediamine, ethylenediamine, 1,3-propanediamine, 1,4-butanediamine, 1,6-hexanediamine, benzidine;

[0009] Preferably, the second monomer includes at least one of hydroquinone, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenylmethane, biphenol;

[0010] Preferably, the soft segment compound includes at least one of ethylene glycol, triethylene glycol, tetraethylene glycol, 1,3-propanediol, tripropylene glycol;

[0011] Preferably, the metal salt compound includes at least one of zinc nitrate, copper nitrate, silver nitrate;

[0012] Preferably, the preparation method of the modified first monomer specifically includes the following steps:

[0013] A1. Take the diamine compound and dissolve it in toluene. After introducing flowing nitrogen, add 4,4'-difluorobenzophenone. After mixing evenly, raise the temperature for continuous heating reaction. After the reaction is completed, cool, purify and dry to obtain the first monomer;

[0014] Preferably, in step A1, the mass concentration of the diamine compound in toluene is 0.1 - 0.3 g / mL;

[0015] Preferably, in step A1, the reaction temperature is 110 - 130 °C, and the reaction time is 8 - 12 h;

[0016] A2. Dissolve the first monomer prepared in step A1 in an ethanol aqueous solution, add NaOH, mix well, then dropwise add carbon disulfide, continuously react, after the reaction, carry out a precipitation reaction with ice-cold anhydrous ether, filter by suction, collect the solid, wash and dry it to obtain the modified first monomer;

[0017] Preferably, in step A2, the ethanol aqueous solution is a mixed solution of ethanol and water, wherein the volume ratio between ethanol and water is 2 - 3:1;

[0018] Preferably, in step A2, the reaction is carried out at room temperature, and the reaction time is controlled between 2 - 4 h.

[0019] The present invention also provides a preparation method of a high-strength wear-resistant composite special plastic, which specifically includes the following steps:

[0020] S1. Dissolve the second monomer and the soft segment compound in a toluene / sulfolane mixed solution, under a nitrogen atmosphere, add the modified first monomer, mix evenly, then carry out a first-order reaction, after the reaction ends, continuously raise the temperature to carry out a second-order reaction, after the reaction, carry out natural cooling, add deionized water, centrifuge, collect the precipitate, wash and dry it to obtain a PEEK-based polymer;

[0021] Preferably, in step S1, the volume ratio between toluene and sulfolane in the toluene / sulfolane mixed solution is 7 - 9:10;

[0022] Preferably, in step S1, the temperature of the first-order reaction is 160 - 180 °C, and the reaction time is 4 - 6 h;

[0023] Preferably, in step S1, the temperature of the second-order reaction is 200 - 220 °C, and the reaction time is 18 - 24 h;

[0024] S2. Dissolve the PEEK-based polymer prepared in step S1 in NMP, adjust the pH to 4.5 - 5.5, raise the reaction temperature to 70 - 80 °C, dropwise add a zinc nitrate hexahydrate / ethanol solution, fully stir and react for 6 - 8 h, then cool, filter by suction, collect the solid, and dry it to obtain a Zn-doped PEEK-based polymer;

[0025] S3. Take the Zn-doped PEEK-based polymer prepared in step S2 and polytetrafluoroethylene powder for ball milling, place it on a flat vulcanizer, and after demolding, obtain a composite special plastic.

[0026] The beneficial effects achieved by the present invention are as follows:

[0027] The present invention provides a high-strength and wear-resistant composite special plastic and a preparation method thereof. By modifying the PEEK synthesis monomer, the reaction activity of PEEK matrix polymerization is improved. At the same time, a small amount of soft segment chains containing ether bonds are introduced into the PEEK-based polymer molecular chain to improve the self-lubricating ability of PEEK. Through the doping of metal ions, a highly stable PEEK matrix material is formed, and in the form of PEEK / PTFE composite, a composite special plastic with high strength, high toughness, low friction coefficient and low wear rate based on PEEK is realized, which has significant friction reduction and wear resistance in heavy load, high-speed and high-temperature friction occasions. In the present invention, a diamine compound is polycondensed with 4,4'-difluorobenzophenone to obtain a first monomer containing an imide or amide structure, and a highly active amino group is introduced, providing a controllable active site for subsequent functionalization, and itself having high thermal stability and mechanical strength. Under strong alkaline conditions, CS2 is dropped into the first monomer dispersion liquid to introduce a thiol or disulfide bond structure derived from carbon disulfide, and a highly active sulfur functional group is obtained in the polymer chain, providing a site for subsequent coordination with metal ions, and at the same time, a lubricating layer can be formed at high temperature. In the present invention, the second monomer mostly uses compounds with benzene ring structure and phenol structure. During the formation of the PEEK matrix material, a soft segment compound with ether bond and terminal hydroxyl group is added. The aliphatic ether bond (-O-) itself has low rigidity, increasing the flexibility of the PEEK-based polymer chain and enhancing the relative sliding performance between molecular chains, thus contributing to friction reduction. The compound introducing the ether bond may affect the crystallinity of PEEK. PEEK itself has high crystallinity, and the introduction of the ether bond may reduce this crystallinity, thus affecting its mechanical properties, wear resistance and other properties; in the present invention, after Zn 2+ binds to sites such as thiol and carbonyl, the coordination of the sulfur functional group with Zn 2+ is beneficial to realizing strong interfacial bonding between the polymer chain and the inorganic phase, enhancing the overall wear resistance and anti-peeling performance of the composite. After ball milling Zn-doped PEEK and polytetrafluoroethylene (PTFE) and hot pressing and molding, PTFE is distributed at the matrix interface after flowing at high temperature. During the friction process, frictional heat and frictional shear force are generated on the surface of the composite special plastic, resulting in wear and damage on the surface of the composite special plastic. After the polymer molecular chain is damaged, the chemical bond between Zn-S is broken, so that Zn is exposed. Zn has high activation energy and surface energy, and is rapidly oxidized during the friction process to form ZnO particles on the surface of the composite special plastic, improving the composite special plastic Description of the Drawings

[0028] Figure 1 1H NMR images of the first monomer and the modified first monomer prepared in Example 2 of the present invention;

[0029] Figure 2 Infrared spectrum image of the composite special plastic prepared in Example 2 of the present invention;

[0030] Figure 3 SEM image of the surface of the composite special plastic prepared in Example 2 of the present invention after a friction test;

[0031] Figure 4 Tribological performance result diagrams of the special plastics prepared in Examples 1-3 and Comparative Examples 1-3 of the present invention under different loads;

[0032] Figure 5 Tribological performance result diagrams of the special plastics prepared in Examples 1-3 and Comparative Examples 1-3 of the present invention at different rotational speeds.

[0033] The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention, and do not constitute a limitation to the present invention. Detailed implementation manners

[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments; based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0035] Unless otherwise defined, all professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to the described content can be applied to the present invention. The preferred implementation methods and materials described herein are only for illustrative purposes and do not limit the content of the present application.

[0036] The experimental methods in the following embodiments are all conventional methods unless otherwise specified; the test materials and test strains used in the following embodiments are all obtained from commercial channels unless otherwise specified.

[0037] Example 1

[0038] This example provides a high-strength wear-resistant composite special plastic. The preparation raw materials of the composite special plastic include the following components in parts by weight: 8.12 parts of modified first monomer, 2.0 parts of hydroquinone, 0.4 part of tetraethylene glycol, 5.0 parts of zinc nitrate hexahydrate, and 4 parts of polytetrafluoroethylene powder;

[0039] The raw materials for preparing the modified first monomer include the following components in parts by weight: 5.4 parts of p-phenylenediamine, 7.2 parts of 4,4'-difluorobenzophenone, 3.8 parts of carbon disulfide, and 2.0 parts of NaOH;

[0040] The preparation method of the modified first monomer specifically includes the following steps:

[0041] A1. Accurately weigh 5.4 g of p-phenylenediamine and place it in a flask. Use molecular sieve to dry toluene, take 30 mL of dry toluene and add it to the flask to fully dissolve p-phenylenediamine. Then, introduce flowing nitrogen. After 20 min, accurately weigh 7.2 g of 4,4'-difluorobenzophenone and add it to the reaction system. Stir at a speed of 200 rpm. After 30 min, raise the reaction temperature to 120 °C and carry out reflux reaction for 10 h. After the reaction system cools to room temperature, rotary evaporate to remove the excess reaction solvent, purify by recrystallization, and place it in a vacuum drying oven at 40 °C for 6 h to obtain the first monomer;

[0042] A2. Accurately weigh the first monomer and place it in a flask. Add 100 mL of ethanol aqueous solution (V 乙醇 :V 水 =2:1) to fully dissolve the first monomer. Then add 2 g of NaOH and stir at a speed of 300 rpm for full dispersion. Transfer the reaction system to an ice bath. Dropwise add 3.0 mL of carbon disulfide to the reaction system at a speed of 0.1 mL / min, and keep stirring at a speed of 300 rpm for the reaction. After the dropping is completed, continue stirring the reaction for 30 min under the condition of ice bath, then raise the reaction temperature to room temperature and continue stirring for 2 h. After the reaction is completed, add ice-cold anhydrous ether for precipitation reaction. Vacuum filter to collect the solid, and wash it three times successively with anhydrous ether, anhydrous ethanol and deionized water, and then place it in a vacuum drying oven at 50 °C for 2 h to obtain the modified first monomer;

[0043] This embodiment provides a preparation method of a high-strength wear-resistant composite special plastic, which specifically includes the following steps:

[0044] S1. Weigh 2.0 g of hydroquinone and 0.4 g of tetraethylene glycol dimethyl ether accurately and place them in a flask. Prepare a toluene / sulfolane mixed solution according to a volume ratio of 7:10 and add it to the flask. After fully dissolving hydroquinone and tetraethylene glycol dimethyl ether, introduce flowing nitrogen into the reaction system. After 20 min, add 8.12 g of modified first monomer, stir and mix at a speed of 250 rpm for 1 h, then raise the reaction temperature to 160 °C, continue stirring and reacting for 5 h, remove the condensed water layer, collect the toluene layer compound, raise the reaction temperature to 220 °C, continue reacting for 18 h, transfer the reaction system to deionized water, stir rapidly until no more precipitation occurs, centrifuge at 3000 rpm for 20 min, collect the precipitate, wash it repeatedly three times with deionized water and absolute ethanol, and then dry it in vacuum at 60 °C for 10 h to obtain a PEEK-based polymer;

[0045] S2. Dissolve the PEEK-based polymer prepared in step S1 in NMP, adjust the pH to 5.5, raise the reaction temperature to 70 °C, and gradually add a zinc nitrate hexahydrate / ethanol solution with a mass concentration of 0.1 g / mL at a rate of 1 mL / min for 50 mL. After dropping, stir and react fully for 6 h. After the reaction is completed, cool, filter by suction, collect the solid, and dry it to obtain a Zn-doped PEEK-based polymer;

[0046] S3. Take the Zn-doped PEEK-based polymer prepared in step A2 and 4.0 g of polytetrafluoroethylene powder and place them in a planetary ball mill. Mill at a speed of 500 rpm for 3 h, then transfer to a mold, adjust the parameters of the flat vulcanizer, pre-press at 12 MPa for 2 min, raise the temperature to 360 °C, hot-press at 12 MPa for 1 h, cool to room temperature, and demold to obtain a composite special plastic.

[0047] Example 2

[0048] This example provides a high-strength wear-resistant composite special plastic. The preparation raw materials of the composite special plastic include the following components in parts by weight: 7.2 parts of modified first monomer, 1.75 parts of hydroquinone, 0.25 part of ethylene glycol, 6.0 parts of zinc nitrate hexahydrate, and 2.8 parts of polytetrafluoroethylene powder;

[0049] The preparation raw materials of the modified first monomer include the following components in parts by weight: 3.0 parts of ethylenediamine, 7.2 parts of 4,4'-difluorobenzophenone, 4.5 parts of carbon disulfide, and 2.4 parts of NaOH;

[0050] The preparation method of the modified first monomer specifically includes the following steps:

[0051] A1. Weigh 3.0 g of ethylenediamine accurately and place it in a flask. Dry toluene using molecular sieves, take 30 mL of dried toluene and add it to the flask. After fully dissolving p-phenylenediamine, introduce flowing nitrogen. After 20 min, weigh 7.2 g of 4,4'-difluorobenzophenone accurately and add it to the reaction system. Stir at a speed of 200 rpm. After 30 min, raise the reaction temperature to 110 °C and carry out a reflux reaction for 12 h. After the reaction system cools to room temperature, remove the excess reaction solvent by rotary evaporation. After purification by recrystallization, place it in a vacuum dryer at 40 °C for 6 h to obtain the first monomer;

[0052] A2. Weigh the first monomer accurately and place it in a flask. Add 100 mL of an ethanol-water solution (V 乙醇 :V 水 = 3:1) to fully dissolve the first monomer. Then add 2.4 g of NaOH and stir at a speed of 300 rpm for full dispersion. Transfer the reaction system to an ice bath. Dropwise add 3.6 mL of carbon disulfide to the reaction system at a speed of 0.1 mL / min while maintaining a stirring speed of 300 rpm. After the addition is complete, continue stirring the reaction under ice bath conditions for 30 min. Then raise the reaction temperature to room temperature and continue stirring for 3 h. After the reaction is completed, add ice-cold anhydrous ether for precipitation reaction. After vacuum filtration to collect the solid, wash it three times successively with anhydrous ether, anhydrous ethanol, and deionized water, and then place it in a vacuum dryer at 50 °C for 2 h to obtain the modified first monomer;

[0053] The structures of the first monomer and the modified first monomer prepared in Example 2 were analyzed by nuclear magnetic resonance hydrogen spectroscopy. Figure 1 The nuclear magnetic resonance hydrogen spectroscopy images of the first monomer and the modified first monomer prepared in Example 2 of the present invention are shown in the figure. Among them, A is the modified first monomer and B is the first monomer. The nuclear magnetic resonance hydrogen spectroscopy data of the first monomer: 1 H NMR (DMSO, 300 MHz) 7.93 (m, 2H), 7.78 (m, 2H), 7.46 (m, 2H), 7.42 (m, 2H), 7.34 (m, 2H), 6.63 (m, 2H), 5.30 (s, 2H). The nuclear magnetic resonance hydrogen spectroscopy data of the modified first monomer: 11H NMR (DMSO, 300 MHz): δ 17.24 (s, 1H, NH), 7.95 (s, 1H, CH=N), 7.78 (dd, J = 8.6, 5.4 Hz, 2H), 7.56 (d, J = 8.8 Hz, 2H), 7.45 (d, J = 8.8 Hz, 2H), 7.42 (dd, J = 8.6, 5.4 Hz, 2H), 7.08 (dd, J = 8.6, 5.4 Hz, 2H), 7.06 (dd, J = 8.6, 5.4 Hz, 2H). According to the 1H NMR data, it shows that the first monomer in Example 1 has an active amino group. After the reaction in Step A2, the amino group becomes a secondary amino group, indicating that carbon disulfide reacts with the amino group.

[0054] This example provides a preparation method of a high-strength wear-resistant composite special plastic, which specifically includes the following steps:

[0055] S1. Accurately weigh 1.75 g of hydroquinone and 0.25 g of ethylene glycol and place them in a flask. Prepare a toluene / sulfolane mixed solution according to a volume ratio of 9:10, add it to the flask to fully dissolve hydroquinone and ethylene glycol, then introduce flowing nitrogen into the reaction system. After 20 min, add 7.2 g of the modified first monomer, stir and mix at a speed of 250 rpm for 1 h, then raise the reaction temperature to 170 °C, continuously stir and react for 6 h, remove the condensed water layer, collect the toluene layer compound, raise the reaction temperature to 200 °C, continue to react for 24 h, transfer the reaction system to deionized water, quickly stir until no more precipitation occurs, centrifuge at 3000 rpm for 20 min, collect the precipitate, wash it repeatedly three times with deionized water and absolute ethanol, and then dry it in vacuum at 60 °C for 10 h to obtain a PEEK-based polymer;

[0056] S2. Dissolve the PEEK-based polymer prepared in Step S1 in NMP, adjust the pH to 5.0, raise the reaction temperature to 80 °C, and gradually add a zinc nitrate hexahydrate / ethanol solution with a mass concentration of 0.1 g / mL at a rate of 1 mL / min for 60 mL. Stir and react fully for 7 h, then cool, filter by suction, collect the solid, and dry it to obtain a Zn-doped PEEK-based polymer;

[0057] S3. Take the Zn-doped PEEK-based polymer prepared in Step S2 and 2.8 g of polytetrafluoroethylene powder and place them in a planetary ball mill. Ball mill at a speed of 500 rpm for 3 h, then transfer to a mold, adjust the parameters of the flat vulcanizer, pre-press at 12 MPa for 2 min, raise the temperature to 360 °C, hot press at 12 MPa for 1 h, then cool to room temperature and demold to obtain the composite special plastic.

[0058] The Fourier transform infrared spectrometer was used to analyze the infrared spectra of the first monomer and the modified first monomer prepared in Example 2. Figure 2 This is the infrared spectrum image of the composite special plastic prepared in Example 2 of the present invention. Among them, A is conventional PEEK, B is Zn-doped PEEK-based polymer, and C is the composite special plastic. As shown in the figure, in curve B, the N-H stretching vibration peak is at 3430–3300 cm -1 and the C=N stretching vibration peak appears at 1650-1620 cm -1 The C=S stretching vibration peak appears significantly at 1180-1160 cm -1 and the characteristic peak of Zn-S appears at 450-420 cm -1 indicating that the Zn-doped PEEK-based polymer prepared in this example was successfully synthesized. The characteristic peak of aromatic ether C-O-C of conventional PEEK (curve A) appears at about 1290-1220 cm -1 and the peak shape is often divided into two adjacent absorption peaks, while the characteristic peak of aliphatic ether C-O-C existing in curve B and curve C is often more single and the peak shape is narrower; in the composite special plastic (curve C), the characteristic peak of obvious CF2 appears, including antisymmetric stretching (1220-1200 cm -1 ) and symmetric stretching (1170-1140 cm -1 ) and CF2 wagging / bending (990-970 cm -1 ) and out-of-plane bending (640-620 cm -1 ), indicating that the composite special plastic prepared in this example was successfully synthesized.

[0059] Example 3

[0060] This example provides a high-strength wear-resistant composite special plastic. The preparation raw materials of the composite special plastic include the following components in parts by weight: 9.6 parts of modified first monomer, 1.5 parts of hydroquinone, 0.9 part of triethylene glycol, 7.5 parts of zinc nitrate hexahydrate, and 4.5 parts of polytetrafluoroethylene powder;

[0061] The preparation raw materials of the modified first monomer include the following components in parts by weight: 9.2 parts of benzidine, 8.3 parts of 4,4'-difluorobenzophenone, 5.3 parts of carbon disulfide, and 2.8 parts of NaOH;

[0062] The preparation method of the modified first monomer specifically includes the following steps:

[0063] A1. Weigh 9.2 g of benzidine accurately and place it in a flask. Dry toluene using molecular sieves, take 30 mL of dried toluene and add it to the flask to fully dissolve p-phenylenediamine. Then, introduce flowing nitrogen. After 20 min, weigh 8.3 g of 4,4'-difluorobenzophenone accurately and add it to the reaction system. Stir at a speed of 200 rpm. After 30 min, raise the reaction temperature to 130 °C and carry out a reflux reaction for 8 h. After the reaction system cools to room temperature, remove the excess reaction solvent by rotary evaporation. After recrystallization purification, place it in a vacuum dryer at 40 °C for 6 h to obtain the first monomer.

[0064] A2. Weigh the first monomer accurately and place it in a flask. Add 100 mL of ethanol aqueous solution (V 乙醇 :V 水 = 2.5:1) to fully dissolve the first monomer. Then add 2.8 g of NaOH and stir at a speed of 300 rpm for full dispersion. Transfer the reaction system to an ice bath. Dropwise add 4.2 mL of carbon disulfide to the reaction system at a speed of 0.1 mL / min and keep stirring at a speed of 300 rpm for the reaction. After the dropping is completed, continue to stir the reaction for 30 min under the condition of an ice bath. Then raise the reaction temperature to room temperature and continue to stir for 3.5 h. After the reaction is completed, add ice-cold anhydrous ether for precipitation reaction. Vacuum filter to collect the solid, and wash it three times successively with anhydrous ether, anhydrous ethanol and deionized water. Then place it in a vacuum dryer at 50 °C for 2 h to obtain the modified first monomer.

[0065] This example provides a preparation method of a high-strength wear-resistant composite special plastic, which specifically includes the following steps:

[0066] S1. Weigh 1.5 g of hydroquinone and 0.9 g of triethylene glycol accurately and place them in a flask. Prepare a toluene / sulfolane mixed solution according to a volume ratio of 8:10 and add it to the flask to fully dissolve hydroquinone and triethylene glycol. Then introduce flowing nitrogen into the reaction system. After 20 min, add 9.6 of the modified first monomer and stir and mix at a speed of 250 rpm for 1 h. Then raise the reaction temperature to 180 °C and continue to stir the reaction for 4 h. Remove the condensed water layer, collect the toluene layer compound, raise the reaction temperature to 210 °C, and continue the reaction for 21 h. Then transfer the reaction system to deionized water, quickly stir until no more precipitation occurs, centrifuge at 3000 rpm for 20 min, collect the precipitate, wash it three times successively with deionized water and anhydrous ethanol, and then vacuum dry at 60 °C for 10 h to obtain the PEEK-based polymer.

[0067] S2. Dissolve the PEEK-based polymer prepared in step S1 in NMP, adjust the pH to 4.5, raise the reaction temperature to 75 °C, and gradually add a zinc nitrate hexahydrate / ethanol solution with a mass concentration of 0.1 g / mL at a rate of 1 mL / min for 75 mL. After the addition is complete, stir the reaction thoroughly for 8 h. After the reaction is completed, cool, filter by suction, collect the solid, and dry it to obtain a Zn-doped PEEK-based polymer;

[0068] S3. Take 4.5 g of the Zn-doped PEEK-based polymer prepared in step S2 and polytetrafluoroethylene powder and place them in a planetary ball mill. After ball milling at a speed of 500 rpm for 3 h, transfer them to a mold, adjust the parameters of the flat vulcanizer, pre-press at 12 MPa for 2 min, raise the temperature to 360 °C, hot press at 12 MPa for 1 h, then cool to room temperature and demold to obtain a composite special plastic.

[0069] Comparative Example 1

[0070] This comparative example provides a special plastic and its preparation method. The difference from Example 2 is that none of the components of the special plastic include any soft segment compounds, and the soft segment compounds are replaced with hydroquinone in the same weight parts, and the remaining components and component contents are the same as those in Example 1.

[0071] Comparative Example 2

[0072] This comparative example provides a special plastic and its preparation method. The difference from Example 2 is that none of the components of the special plastic include any metal salt compounds, and step S2 is not included in the preparation method of the special plastic, and the remaining components and component contents are the same as those in Example 1.

[0073] Comparative Example 3

[0074] This comparative example provides a special plastic and its preparation method. The difference from Example 2 is that in all components of the special plastic, the modified first monomer is replaced with 4,4'-difluorobenzophenone in the same weight parts, and none of the components contain any metal salt compounds, and step S2 is not included in the preparation method, and the remaining components and component contents are the same as those in Example 1.

[0075] Experimental Example 1

[0076] In this experimental example, a friction test of the composite special plastic prepared in Example 2 was carried out. The friction test used a reciprocating friction and wear tester MET-4000, and the formed parts were subjected to reciprocating friction motion through a spherical friction pair. The test specimens prepared for the test were 20×15×5 mm 3, select a GCr15 friction pair made of spherical stainless steel with a diameter of 5.5 mm, a roughness of Ra = 0.02 μm, reciprocating motion friction in a ball-plane contact, and a hardness of 62 HRC. Set the average sliding speed to 200 mm / min, the load to 50 N, the duration to 2 h, and the reciprocating stroke to 10 mm. Figure 3 This is the SEM image of the surface of the composite special plastic prepared in Example 2 of the present invention after the friction test. As shown in the figure, granular substances can be observed on its surface, indicating that during the friction process of the composite special plastic prepared in Example 2, after the surface is damaged, the exposure of Zn occurs, and ZnO nanoparticles are generated after oxidation, providing a supporting ability for the composite special plastic, thereby improving the friction reduction and wear resistance of the composite special plastic.

[0077] Experimental Example 2

[0078] In this experimental example, a ball-on-disk sliding friction and wear test was carried out on the special plastics prepared in Examples 1-3 and Comparative Examples 1-3 using a multi-functional friction and wear testing machine to analyze their friction performance. The friction pair consists of a 45# steel ball with a diameter of 10 mm and a special plastic test disk with a diameter of 40 mm and a thickness of 4 mm. The friction performance of the special plastics prepared in Examples 1-3 and Comparative Examples 1-3 under different working conditions was investigated. After the wear test, the wear rate was calculated using the following formula:

[0079] Km = V / (F × t);

[0080] where V is the wear volume (mm 3 ), F is the vertical load (N), and t is the experimental time (h).

[0081] Figure 4 This is the tribological performance result graph of the special plastics prepared in Examples 1-3 and Comparative Examples 1-3 of the present invention under different loads. Figure 5 This is the tribological performance result graph of the special plastics prepared in Examples 1-3 and Comparative Examples 1-3 of the present invention under different rotational speeds. Figure 4Among them, the special plastics prepared in Examples 1-3 and Comparative Examples 1-3 showed similar patterns. That is, with the increase of load, the wear rate showed a downward trend. Under the condition of 600 r, during the process of increasing load, the contact area of the special plastic increased, the area of the lubricating film formed by the special plastic increased, and the lubrication effect was enhanced. The wear rate of the special plastics prepared in Examples 1-3 was significantly lower than that in Comparative Examples 1-3. In Comparative Example 1, the soft segment compound was lacking, resulting in a relatively high rigidity of the PEEK-based polymer of the special plastic and poor self-lubrication effect. In Comparative Example 2, the metal salt compound was lacking, and during the friction process, the friction surface lacked the support of nanoparticles, thus leading to an increase in the wear rate. In Comparative Example 3, the monomers of conventional PEEK were used for polymerization reaction, and the internal cross-linking strength of the formed special plastic was low, lacking support force, resulting in an increase in the wear rate and a decrease in the friction reduction and wear resistance performance. In Figure 5 Among them, the special plastics prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to wear tests at 400 r, 500 r, and 600 r under a load condition of 10 N. With the increase of rotational speed, the wear rate of the special plastic increased significantly. During the wear process, the increase in rotational speed would inevitably increase the amount of wear debris and the wear formation, resulting in an increase in the wear rate.

[0082] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention.

[0083] The above description of the present invention and its embodiments is not restrictive. What is shown in the drawings is only one of the embodiments of the present invention, and the actual application is not limited thereto. Generally speaking, if those of ordinary skill in the art are inspired by it and design similar ways and embodiments to this technical solution without creative efforts without departing from the purpose of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A high-strength, wear-resistant composite special plastic, characterized in that: The raw materials for preparing the composite special plastic include the following components in parts by weight: 7-10 parts of a modified first monomer, 1.5-2 parts of a second monomer, 0.25-0.9 parts of a soft segment compound, 5-7.5 parts of a metal salt compound, and 2.8-4.5 parts of polytetrafluoroethylene powder; The raw materials for preparing the modified first monomer include the following components in parts by weight: 3.0-9.2 parts of diamine compound, 7.2-8.3 parts of 4,4'-difluorobenzophenone, 3.5-5.5 parts of carbon disulfide, and 2.0-2.8 parts of NaOH; The second monomer includes at least one of hydroquinone, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenylmethane, and biphenol; The soft segment compound includes at least one of ethylene glycol, triethylene glycol, tetraethylene glycol, 1,3-propylene glycol and tripropylene glycol.

2. The high-strength, wear-resistant composite special plastic according to claim 1, characterized in that: The diamine compound includes at least one of p-phenylenediamine, m-phenylenediamine, ethylenediamine, 1,3-propylenediamine, 1,4-butylenediamine, 1,6-hexanediamine and benzidine.

3. The high-strength, wear-resistant composite special plastic according to claim 2, characterized in that: The metal salt compound includes at least one of zinc nitrate, copper nitrate and silver nitrate.

4. The high-strength, wear-resistant composite special plastic according to claim 3, characterized in that: The method for preparing the modified first monomer specifically comprises the following steps: A1. Dissolve the diamine compound p-phenylenediamine in toluene, introduce flowing nitrogen, add 4,4'-difluorobenzophenone, mix well, raise the temperature to continue heating reaction, cool after the reaction is completed, purify and dry to obtain a first monomer; A2. Dissolve the first monomer prepared in step A1 in ethanol aqueous solution, add NaOH, mix thoroughly, and then add carbon disulfide dropwise. The reaction is carried out at room temperature, and the reaction time is controlled between 2-4 hours. After the reaction is completed, use ice anhydrous ether for precipitation reaction, filter, collect solids, wash and dry to obtain a modified first monomer.

5. The high-strength, wear-resistant composite special plastic according to claim 4, characterized in that: In step A1, the mass concentration of the diamine compound in toluene is 0.1-0.3 g / mL; The reaction temperature is 110-130°C and the reaction time is 8-12h.

6. The high-strength, wear-resistant composite special plastic according to claim 5, characterized in that: In step A2, the ethanol aqueous solution is a mixed solution of ethanol and water, wherein the volume ratio between ethanol and water is 2-3:

1.

7. A method for preparing the high-strength, wear-resistant composite special plastic according to any one of claims 1 to 6, characterized in that: The specific steps include: S1, dissolving the second monomer and the soft segment compound in a toluene / sulfolane mixed solution, adding the modified first monomer under a nitrogen atmosphere, mixing evenly, and performing a first-order reaction. After the reaction is completed, continuously raising the temperature to perform a second-order reaction, cooling naturally after the reaction, adding deionized water, centrifuging, collecting the precipitate, washing, and drying to obtain a PEEK-based polymer; S2, dissolving the PEEK-based polymer prepared in step S1 in NMP, adjusting the pH to 4.5-5.5, raising the reaction temperature to 70-80° C., adding zinc nitrate hexahydrate / ethanol solution dropwise, stirring and reacting for 6-8 hours, cooling, filtering, collecting the solid, and drying to obtain a Zn-doped PEEK-based polymer; S3, taking the Zn-doped PEEK-based polymer prepared in step S2 and subjecting it to ball milling with polytetrafluoroethylene powder, placing it on a flat vulcanizer, and demolding it to obtain a composite special plastic.

8. The method for preparing the high-strength wear-resistant composite special plastic according to claim 7, characterized in that: In step S1, the volume ratio of toluene to sulfolane in the toluene / sulfolane mixed solution is 7-9:

10.

9. The method for preparing the high-strength wear-resistant composite special plastic according to claim 8, characterized in that: In step S1, the temperature of the first-order reaction is 160-180°C, and the reaction time is 4-6 hours; the temperature of the second-order reaction is 200-220°C, and the reaction time is 18-24 hours.

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