A high-strength wear-resistant composite special plastic and its preparation method

Abstract

The invention discloses a high-strength, wear-resistant composite special plastic and a preparation method thereof in the field of special plastic technology. The 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 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 invention improves the reaction activity of PEEK matrix polymerization by modifying PEEK synthetic monomers. 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. By doping with metal ions, a highly stable PEEK matrix material is formed. The PEEK / PTFE composite is adopted to achieve a composite special plastic with high strength, high toughness, low friction coefficient, and low wear rate based on PEEK, which has significant friction reduction and wear resistance in heavy-load, high-speed, and high-temperature friction situations.

Description

Technical Field

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

[0002] Specialty plastics typically consist of a base material and a reinforcement material. Their purpose is to enhance the plastic's mechanical properties, wear resistance, high-temperature resistance, and other specific functions by combining the advantages of both. These composite materials have a wide range of applications, encompassing industries such as aerospace, automotive, electronic equipment, and machinery manufacturing. Specialty plastics can significantly enhance their mechanical strength and wear resistance by adding reinforcing fibers, fillers, or other high-performance materials. However, high-performance specialty plastics typically require expensive reinforcements (such as carbon fiber and glass fiber) and complex manufacturing processes, resulting in production costs significantly higher than conventional plastics. Compared to traditional metal materials, specialty plastics are lighter, which is particularly important in the aerospace and automotive industries. Despite their higher strength, some types of composite materials can become brittle under high stress, especially without appropriate toughening. The processing of specialty plastics is complex, requiring precise control of parameters such as temperature and pressure during production, otherwise the material's ultimate performance may be affected.

[0003] Specialty plastics are a type of high-performance material made by organically combining high-performance matrix resins with various reinforcing phases (such as glass fiber, carbon fiber, aramid fiber, inorganic particles, nanomaterials or sandwich core materials). Their advantage lies in their ability to combine 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 low cost, excellent electrical insulation and chemical resistance, and mature molding process, but relatively high density and average impact toughness; carbon fiber reinforced plastic (CFRP) has extremely high specific strength and specific modulus, good fatigue resistance and high temperature performance, and is suitable for aerospace and high-end racing fields, but the raw material and processing costs are extremely high, and due to its electrical conductivity, it requires additional treatment in insulating situations; aramid (Kevlar) reinforced plastic is known for its excellent impact resistance and ballistic resistance, and has low density and heat aging resistance, but the fiber is easy to absorb moisture, the processing and cutting cost is high, and it is sensitive to strong acid and strong alkali environments; inorganic particle or flaky filler composite plastics (such as adding calcium carbonate, talc or glass beads) can significantly reduce costs, improve wear resistance or flame retardancy, and improve dimensional stability, but high When the content is too high, it is easy to cause the material to become more brittle and have poor processing fluidity; nano-reinforcement phases such as montmorillonite, carbon nanotubes or graphene dispersed in nano-composite plastics can significantly improve the mechanical, thermal and electrical properties at extremely low addition amounts, while imparting flame retardant or self-lubricating functions, but the nanoparticles are easy to agglomerate, and the dispersion is difficult and costly; structural layered / sandwich plastics achieve excellent bending stiffness-to-weight ratio and sound insulation and heat insulation effects by sandwiching lightweight foam or honeycomb core materials between high-strength surface layers, but the preparation process is complicated, interlayer debonding is prone to occur, and repair and recycling are difficult; in addition, by physical blending or chemical copolymerization of a variety of high-performance thermoplastic resins (such as PPS, PEEK, PEI, etc.), a blend or copolymer system with high temperature resistance, flame retardancy and excellent processability can be obtained, but the compatibility is poor and phase separation is easy, and the processing parameters are strict. In summary, different types of specialty plastics have their own advantages and disadvantages. It is necessary to rationally select the combination of matrix and reinforcement based on multiple factors such as performance requirements, cost and output, processing technology, use environment and sustainable recycling in order to design high-performance materials that meet functional requirements and are economical. Summary of the Invention

[0004] In view of the above situation, in order to overcome the defects of the prior art, the present invention provides a high-strength and wear-resistant composite special plastic and a preparation method thereof. The present invention improves the reaction activity of PEEK matrix polymerization by modifying the PEEK synthetic monomer. 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. By doping with metal ions, a highly stable PEEK matrix material is formed. The PEEK / PTFE composite form is adopted to achieve a composite special plastic based on PEEK with high strength, high toughness, low friction coefficient and low wear rate, which has significant friction reduction and wear resistance in heavy load, high speed and high temperature friction occasions.

[0005] In order to achieve the above-mentioned object, the technical solution adopted by the present invention is as follows: The present invention proposes a high-strength and wear-resistant composite special plastic, and the raw materials for preparing 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 parts of soft segment compound, 5-7.5 parts of metal salt compound, 2.8-4.5 parts of polytetrafluoroethylene powder;

[0007] Preferably, the raw materials for preparing the modified first monomer include the following components in parts by weight: 3.0-9.2 parts of a 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;

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

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

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

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

[0012] Preferably, the method for preparing the modified first monomer specifically comprises the following steps:

[0013] A1. Dissolve a diamine compound in toluene, introduce flowing nitrogen, and then add 4,4'-difluorobenzophenone. Mix thoroughly, then increase the temperature for continuous heating. After the reaction is complete, cool, purify, and dry to obtain a 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 thoroughly, and then add carbon disulfide dropwise. Continue the reaction. After the reaction, precipitate with ice-cold anhydrous ether. Filter, collect the solid, wash, and dry to obtain a 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 and 4 hours.

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

[0020] 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 conducting a first-order reaction. After the reaction is completed, continuously raising the temperature to conduct a second-order reaction. After the reaction, naturally cooling is carried out, deionized water is added, centrifugation is performed, and the precipitate is collected, washed, and dried to obtain a PEEK-based polymer;

[0021] Preferably, in step S1, the volume ratio of toluene to 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 4-6h;

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

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

[0025] S3. The Zn-doped PEEK-based polymer prepared in step S2 is subjected to ball milling treatment with polytetrafluoroethylene powder, and the mixture is placed on a flat vulcanizer. After demolding, a composite special plastic is obtained.

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

[0027] The present invention provides a high-strength, wear-resistant composite special plastic and a preparation method thereof. The present invention improves the reaction activity of PEEK matrix polymerization by modifying PEEK synthetic monomers. 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. A highly stable PEEK matrix material is formed by doping with metal ions. The PEEK / PTFE composite form is adopted to achieve a composite special plastic based on PEEK with high strength, high toughness, low friction coefficient and low wear rate. The composite special plastic has significant friction reduction and wear resistance in heavy-load, high-speed and high-temperature friction situations. In the present invention, a diamine compound is polycondensed with 4,4'-difluorobenzophenone to obtain a first monomer containing an imide or amide structure. This monomer also introduces a highly active amino group, providing a controllable active site for subsequent functionalization. The monomer itself also has high thermal stability and mechanical strength. Under strong alkaline conditions, CS2 is added dropwise to the first monomer dispersion to introduce a thiol or disulfide bond structure derived from carbon disulfide. This results in highly active sulfhydryl functional groups in the polymer chain, providing sites for subsequent coordination with metal ions and capable of forming a lubricating layer at high temperatures. In the present invention, the second monomer is mostly a compound with a benzene ring structure and a phenol structure. In the process of forming the PEEK matrix material, a soft segment compound with an ether bond and a terminal hydroxyl group is added. The fatty ether bond (-O-) itself has a low rigidity, which increases the flexibility of the PEEK-based polymer chain and enhances the relative sliding performance between the molecular chains, thereby contributing to friction reduction. The compound introduced with the ether bond may affect the crystallinity of PEEK. PEEK itself has a high crystallinity, and the introduction of the ether bond may reduce this crystallinity, thereby affecting its mechanical properties, wear resistance and other properties. In the present invention, Zn 2+ After binding to thiol, carbonyl and other sites, the sulfur functional group and Zn 2+ The coordination is conducive to achieving strong interfacial bonding between the polymer chain and the inorganic phase, enhancing the overall wear resistance and anti-stripping properties of the composite. Zn-doped PEEK and polytetrafluoroethylene (PTFE) are ball-milled and hot-pressed. After high-temperature flow, PTFE is distributed at the matrix interface. During the friction process, friction heat and friction 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 destroyed, the chemical bond between Zn-S is broken, thereby exposing Zn. Zn has high activation energy and surface energy. After being rapidly oxidized during the friction process, ZnO particles are formed on the surface of the composite special plastic, thereby improving the friction reduction and wear resistance of the composite special plastic. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0029] Figure 2 This is an infrared spectrum image of the composite special plastic prepared in Example 2 of the present invention;

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

[0031] Figure 4 Graphs showing the tribological properties of the special plastics prepared in Examples 1-3 and Comparative Examples 1-3 of the present invention under different loads;

[0032] Figure 5 The graph shows the tribological properties of the special plastics prepared in Examples 1-3 of the present invention and Comparative Examples 1-3 at different rotation speeds.

[0033] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those familiar to those skilled in the art. Furthermore, any methods and materials similar or equivalent to those described herein can be applied to the present invention. The preferred embodiments and materials described herein are for illustrative purposes only and are not intended to limit the scope of this application.

[0036] The experimental methods in the following examples, unless otherwise specified, are conventional methods; the test materials and test strains used in the following examples, unless otherwise specified, are purchased from commercial channels. Example 1

[0037] This embodiment provides a high-strength, wear-resistant composite special plastic. The raw materials for preparing the composite special plastic include the following components in parts by weight: 8.12 parts of a modified first monomer, 2.0 parts of hydroquinone, 0.4 parts of tetraethylene glycol, 5.0 parts of zinc nitrate hexahydrate, and 4 parts of polytetrafluoroethylene powder.

[0038] 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;

[0039] The preparation method of the modified first monomer specifically comprises the following steps:

[0040] A1. Accurately weigh 5.4 g of p-phenylenediamine and place it in a flask. Dry the toluene with molecular sieves. Add 30 mL of dry toluene to the flask to fully dissolve the p-phenylenediamine. Flow nitrogen gas is then introduced. After 20 minutes, accurately weigh 7.2 g of 4,4'-difluorobenzophenone and add it to the reaction system. Stir at 200 rpm. After 30 minutes, raise the reaction temperature to 120°C and reflux for 10 hours. After cooling the reaction system to room temperature, remove excess reaction solvent by rotary evaporation. Purify the mixture by recrystallization and vacuum drying at 40°C for 6 hours to obtain the first monomer.

[0041] A2. Accurately weigh the first monomer and place it in a flask. Add 100 mL of ethanol solution (V 乙醇 :V 水 =2:1) ​​After fully dissolving the first monomer, 2 g of NaOH was added, and after stirring at 300 rpm for thorough dispersion, the reaction system was transferred to ice water, and 3.0 mL of carbon disulfide was added dropwise to the reaction system at a rate of 0.1 mL / min, while stirring at 300 rpm for reaction. After the addition was complete, the reaction was stirred in an ice-water bath for 30 minutes, and then the reaction temperature was raised to room temperature and stirred for 2 hours. After the reaction was completed, ice-cold anhydrous ether was added for precipitation reaction. The solid was collected by vacuum filtration, and then washed repeatedly with anhydrous ether, anhydrous ethanol, and deionized water three times in sequence, and then dried in vacuo at 50°C for 2 hours to obtain the modified first monomer;

[0042] This embodiment provides a method for preparing a high-strength, wear-resistant composite special plastic, which specifically includes the following steps:

[0043] S1. Accurately weigh 2.0 g of hydroquinone and 0.4 g of tetraethylene glycol and place them in a flask. Prepare a toluene / sulfolane mixed solution in a volume ratio of 7:10, add it to the flask, fully dissolve the hydroquinone and tetraethylene glycol, and then introduce flowing nitrogen into the reaction system. After 20 minutes, add 8.12 g of the modified first monomer, stir and mix at 250 rpm for 1 hour, increase the reaction temperature to 160°C, continue stirring and react for 5 hours, remove the condensed water layer, collect the toluene layer compound, increase the reaction temperature to 220°C, continue the reaction for 18 hours, transfer the reaction system to deionized water, stir rapidly until no more precipitate is precipitated, place it at 3000 rpm for centrifugation for 20 minutes, collect the precipitate, wash it repeatedly with deionized water and anhydrous ethanol three times, and then vacuum dry it at 60°C for 10 hours to obtain a PEEK-based polymer;

[0044] S2. Dissolve the PEEK-based polymer prepared in step S1 in NMP, adjust the pH to 5.5, increase the reaction temperature to 70° C., add zinc nitrate hexahydrate / ethanol solution with a mass concentration of 0.1 g / mL dropwise, add 50 mL at a rate of 1 mL / min, and after the addition is complete, stir and react for 6 hours. After the reaction is complete, cool, filter, collect the solid, and dry to obtain a Zn-doped PEEK-based polymer;

[0045] S3. Take 4.0 g of the Zn-doped PEEK-based polymer and polytetrafluoroethylene powder prepared in step A2 and place them in a planetary ball mill. After ball milling at 500 rpm for 3 hours, transfer them to a mold, adjust the parameters of the flat vulcanizing agent, pre-press at 12 MPa for 2 minutes, increase the temperature to 360°C, hot press at 12 MPa for 1 hour, cool to room temperature, and demold to obtain a composite special plastic. Example 2

[0046] This embodiment provides a high-strength, wear-resistant composite special plastic. The raw materials for preparing the composite special plastic include the following components in parts by weight: 7.2 parts of a modified first monomer, 1.75 parts of hydroquinone, 0.25 parts of ethylene glycol, 6.0 parts of zinc nitrate hexahydrate, and 2.8 parts of polytetrafluoroethylene powder.

[0047] The raw materials for preparing 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;

[0048] The preparation method of the modified first monomer specifically comprises the following steps:

[0049] A1. Accurately weigh 3.0 g of ethylenediamine and place it in a flask. Dry the toluene with molecular sieves. Add 30 mL of dry toluene to the flask to fully dissolve the p-phenylenediamine. Flow nitrogen gas is then introduced. After 20 minutes, accurately weigh 7.2 g of 4,4'-difluorobenzophenone and add it to the reaction system. Stir at 200 rpm. After 30 minutes, raise the reaction temperature to 110°C and reflux for 12 hours. After cooling the reaction system to room temperature, remove excess reaction solvent by rotary evaporation. Purify the mixture by recrystallization and vacuum drying at 40°C for 6 hours to obtain the first monomer.

[0050] A2. Accurately weigh the first monomer and place it in a flask. Add 100 mL of ethanol solution (V 乙醇 :V 水 =3:1) After fully dissolving the first monomer, 2.4 g of NaOH was added, and after stirring at 300 rpm for thorough dispersion, the reaction system was transferred to ice water, and 3.6 mL of carbon disulfide was added dropwise to the reaction system at a rate of 0.1 mL / min, while stirring at 300 rpm for reaction. After the addition was complete, the reaction was continued with stirring in an ice-water bath for 30 minutes, and the reaction temperature was raised to room temperature and stirred for 3 hours. After the reaction was completed, ice-cold anhydrous ether was added for precipitation reaction. The solid was collected by vacuum filtration, and then washed repeatedly with anhydrous ether, anhydrous ethanol, and deionized water three times in sequence, and then dried in vacuo at 50°C for 2 hours to obtain the modified first monomer;

[0051] The structures of the first monomer and the modified first monomer prepared in Example 2 were analyzed by hydrogen nuclear magnetic resonance spectroscopy. Figure 1 The H NMR spectra of the first monomer and the modified first monomer prepared in Example 2 of the present invention are shown in the figure, where A is the modified first monomer and B is the first monomer. The H NMR spectra data of the first monomer are as follows: 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). H NMR spectrum data of the modified first monomer: 1H NMR (DMSO, 300 MHz) 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 hydrogen NMR spectrum data, the first monomer in Example 1 has an active amino group. After the reaction in step A2, the amino group is converted into a secondary amino group, indicating that carbon disulfide reacts with the amino group.

[0052] This embodiment provides a method for preparing a high-strength, wear-resistant composite special plastic, which specifically includes the following steps:

[0053] 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 in a volume ratio of 9:10, add the solution to the flask to fully dissolve the hydroquinone and ethylene glycol, introduce flowing nitrogen into the reaction system, and after 20 minutes, add 7.2 g of the modified first monomer. Stir and mix at 250 rpm for 1 hour, raise the reaction temperature to 170°C, continue stirring and react for 6 hours, remove the condensed water layer, collect the toluene layer compound, raise the reaction temperature to 200°C, continue the reaction for 24 hours, transfer the reaction system to deionized water, stir rapidly until no more precipitate is precipitated, centrifuge at 3000 rpm for 20 minutes, collect the precipitate, wash it repeatedly with deionized water and anhydrous ethanol three times, and dry it in vacuo at 60°C for 10 hours to obtain a PEEK-based polymer.

[0054] S2. Dissolve the PEEK-based polymer prepared in step S1 in NMP, adjust the pH to 5.0, increase the reaction temperature to 80° C., add a 0.1 g / mL zinc nitrate hexahydrate / ethanol solution dropwise at a rate of 60 mL / min, stir and react for 7 h, cool, filter, collect the solid, and dry to obtain a Zn-doped PEEK-based polymer;

[0055] S3. Take 2.8 g of the Zn-doped PEEK-based polymer and polytetrafluoroethylene powder prepared in step S2 and place them in a planetary ball mill. After ball milling at 500 rpm for 3 hours, transfer them to a mold, adjust the parameters of the flat vulcanizing agent, pre-press at 12 MPa for 2 minutes, increase the temperature to 360°C, hot press at 12 MPa for 1 hour, cool to room temperature, and demold to obtain a composite special plastic.

[0056] The first monomer and the modified first monomer prepared in Example 2 were analyzed by infrared spectroscopy using a Fourier transform infrared spectrometer. Figure 2 This is the infrared spectrum image of the composite special plastic prepared in Example 2 of the present invention, wherein 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, at 3430–3300 cm -1 The NH stretching vibration peak is at 1650-1620 cm -1 The stretching vibration peak of C=N appears at 1180-1160cm -1 There is an obvious C=S stretching vibration peak at 450-420cm -1 The characteristic peak of Zn-S appears, indicating that the Zn-doped PEEK-based polymer prepared in this example was successfully synthesized. The characteristic peak of the aromatic ether COC of conventional PEEK (curve A) is at about 1290-1220 cm -1 The peaks are often divided into two adjacent absorption peaks, while the characteristic peaks of fatty ether COC in curves B and C are often single and narrower; in the composite special plastic (curve C), obvious characteristic peaks of CF2 appear, including antisymmetric stretching (1220-1200cm -1 ) and symmetrical telescopic (1170-1140cm -1 ) and CF2 swing / bend (990-970cm -1 ) and outer plane bending (640-620cm -1 ), indicating that the composite special plastic prepared in this embodiment was successfully synthesized. Example 3

[0057] This embodiment provides a high-strength, wear-resistant composite special plastic. The raw materials for preparing the composite special plastic include the following components in parts by weight: 9.6 parts of a modified first monomer, 1.5 parts of hydroquinone, 0.9 parts of triethylene glycol, 7.5 parts of zinc nitrate hexahydrate, and 4.5 parts of polytetrafluoroethylene powder.

[0058] The raw materials for preparing 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;

[0059] The preparation method of the modified first monomer specifically comprises the following steps:

[0060] A1. Accurately weigh 9.2 g of benzidine and place it in a flask. Dry the toluene with molecular sieves. Add 30 mL of dry toluene to the flask to fully dissolve the p-phenylenediamine. Flow nitrogen gas is then introduced. After 20 minutes, accurately weigh 8.3 g of 4,4'-difluorobenzophenone and add it to the reaction system. Stir at 200 rpm. After 30 minutes, raise the reaction temperature to 130°C and reflux for 8 hours. After cooling the reaction system to room temperature, remove excess reaction solvent by rotary evaporation. Purify the mixture by recrystallization and vacuum drying at 40°C for 6 hours to obtain the first monomer.

[0061] A2. Accurately weigh the first monomer and place it in a flask. Add 100 mL of ethanol solution (V 乙醇 :V 水 =2.5:1) After fully dissolving the first monomer, 2.8 g of NaOH was added and the mixture was stirred at 300 rpm for full dispersion. The reaction system was then transferred to ice water and 4.2 mL of carbon disulfide was added dropwise at a rate of 0.1 mL / min. The reaction was stirred at 300 rpm. After the addition was complete, the mixture was stirred in an ice-water bath for 30 minutes. The reaction temperature was raised to room temperature and stirred for 3.5 hours. After the reaction was completed, ice-cold anhydrous ether was added for precipitation. The solid was collected by vacuum filtration and washed three times with anhydrous ether, anhydrous ethanol, and deionized water, respectively. The solid was then dried in vacuo at 50°C for 2 hours to obtain the modified first monomer.

[0062] This embodiment provides a method for preparing a high-strength, wear-resistant composite special plastic, which specifically includes the following steps:

[0063] S1. Accurately weigh 1.5 g of hydroquinone and 0.9 g of triethylene glycol and place them in a flask. Prepare a toluene / sulfolane mixed solution in a volume ratio of 8:10, add the solution to the flask to fully dissolve the hydroquinone and triethylene glycol, and then introduce flowing nitrogen into the reaction system. After 20 minutes, add 9.6 g of the modified first monomer, stir and mix at 250 rpm for 1 hour, raise the reaction temperature to 180°C, continue stirring and react for 4 hours, remove the condensed water layer, collect the toluene layer compound, raise the reaction temperature to 210°C, continue the reaction for 21 hours, transfer the reaction system to deionized water, stir rapidly until no more precipitate is precipitated, centrifuge at 3000 rpm for 20 minutes, collect the precipitate, wash it repeatedly with deionized water and anhydrous ethanol three times, and then vacuum dry it at 60°C for 10 hours to obtain a PEEK-based polymer.

[0064] S2. Dissolve the PEEK-based polymer prepared in step S1 in NMP, adjust the pH to 4.5, increase the reaction temperature to 75° C., add zinc nitrate hexahydrate / ethanol solution with a mass concentration of 0.1 g / mL dropwise, add 75 mL at a rate of 1 mL / min, and after the addition is complete, stir and react for 8 hours. After the reaction is complete, cool, filter, collect the solid, and dry to obtain a Zn-doped PEEK-based polymer;

[0065] S3. Take 4.5 g of the Zn-doped PEEK-based polymer and polytetrafluoroethylene powder prepared in step S2 and place them in a planetary ball mill. After ball milling at 500 rpm for 3 hours, transfer them to a mold, adjust the parameters of the flat vulcanizing agent, pre-press at 12 MPa for 2 minutes, increase the temperature to 360°C, hot press at 12 MPa for 1 hour, cool to room temperature, and demold to obtain a composite special plastic.

[0066] Comparative Example 1

[0067] This comparative example provides a special plastic and a preparation method thereof, which differs from Example 2 only in that all components of the special plastic do not include any soft segment compound, wherein the soft segment compound is replaced by the same weight portion of hydroquinone, and the remaining components and component contents are the same as those in Example 1.

[0068] Comparative Example 2

[0069] This comparative example provides a special plastic and a preparation method thereof, which differs from Example 2 only in that all components of the special plastic do not include any metal salt compound, the preparation method of the special plastic does not include step S2, and the remaining components and component contents are the same as those in Example 1.

[0070] Comparative Example 3

[0071] This comparative example provides a special plastic and a preparation method thereof. The difference between this comparative example and Example 2 is that, among all components of the special plastic, the modified first monomer is replaced by 4,4'-difluorobenzophenone in equal parts by weight, and the components do not contain any metal salt compounds. The preparation method does not include step S2, and the remaining components and their contents are the same as those in Example 1.

[0072] Experimental Example 1

[0073] This experimental example conducts a friction test on the composite special plastic prepared in Example 2. The friction test uses a reciprocating friction and wear tester MET-4000, and the molded part is subjected to reciprocating friction motion through a spherical friction pair. The test specimen prepared for the test is 20×15×5mm 3, the diameter is 5.5mm, the roughness is Ra=0.02μm, the ball-plane contact is used for reciprocating friction, the hardness is 62HRC, the spherical stainless steel GCr15 friction pair is made of 62HRC, the average sliding speed is set to 200mm / min, the load is 50N, the time is 2h, and the reciprocating motion is 10mm. Figure 3 The surface SEM image of the composite special plastic prepared in Example 2 of the present invention after the friction test is 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, the surface is damaged, resulting in the exposure of Zn. After oxidation, ZnO nanoparticles are generated, which provide support for the composite special plastic, thereby improving the friction reduction and wear resistance of the composite special plastic.

[0074] Experimental Example 2

[0075] This experimental example used a multifunctional friction and wear testing machine to conduct a ball-shaped sliding friction and wear test on the special plastics prepared in Examples 1-3 and Comparative Examples 1-3 to analyze their friction performance. The friction pair consisted of a 45# steel ball with a diameter of 10mm and a special plastic test disc with a diameter of 40mm and a thickness of 4mm. The friction performance of the special plastics prepared in Examples 1-3 and Comparative Examples 1-3 under different operating conditions was examined. After the wear test, the wear rate was calculated using the following formula:

[0076] Km=V / (F×t);

[0077] Where V is the wear volume (mm 3 ), F is the vertical load (N), and t is the experimental time (h).

[0078] Figure 4 The tribological performance results of the special plastics prepared in Examples 1-3 and Comparative Examples 1-3 of the present invention under different loads are shown in FIG. Figure 5 The tribological performance results of the special plastics prepared in Examples 1-3 and Comparative Examples 1-3 of the present invention at different speeds are shown in FIG. Figure 4In the embodiment 1-3 and the comparative example 1-3, the special plastics prepared show similar rules, that is, with the increase of load, the wear rate tends to decrease. Under the condition of 600r, in the process of increasing load, the contact area of ​​the special plastic increases, the area of ​​the lubricating film formed by the special plastic increases, and the lubrication effect is enhanced. The wear rate of the special plastic prepared in the embodiment 1-3 is significantly lower than that in the comparative example 1-3. The comparative example 1 lacks the soft segment compound, which leads to the strong rigidity of the PEEK-based polymer of the special plastic and poor self-lubricating effect. The comparative example 2 lacks the metal salt compound. During the friction process, the friction surface lacks the support of nanoparticles, which leads to an increase in the wear rate. In the comparative example 3, conventional PEEK monomers are used for polymerization reaction, and the internal cross-linking strength of the special plastic formed is low and lacks supporting force, resulting in an increase in the wear rate and a decrease in the friction reduction and wear resistance. Figure 5 In the embodiment 1-3 and the comparative example 1-3, the special plastics prepared were subjected to wear tests at 400r, 500r and 600r under a load of 10N. As the rotation speed increases, the wear rate of the special plastic increases significantly. During the wear process, the increase in rotation speed will inevitably increase the amount of wear debris and increase the wear formation, resulting in an increase in the wear rate.

[0079] While the embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that various changes, modifications, substitutions, and alterations can be made to the embodiments without departing from the principles and spirit of the invention.

[0080] The present invention and its embodiments are described above. Such description is not restrictive. The drawings show only one embodiment of the present invention, and actual applications are not limited thereto. In short, if a person skilled in the art is inspired by the above, and does not deviate from the purpose of the present invention, any method and embodiment similar to the technical solution without creative design shall fall within the scope of protection of the present invention.

Claims

1. A high-strength, wear-resistant composite special plastic, characterized by: 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 zinc nitrate, 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: 5.4-9.2 parts of p-phenylenediamine, 7.2 parts of 4,4'-difluorobenzophenone, 3.5-5.5 parts of carbon disulfide, and 2.0-2.8 parts of NaOH. Alternatively, the raw materials for preparing the modified first monomer include the following components in parts by weight: 3.0-9.2 parts of ethylenediamine, 7.2 parts of 4,4'-difluorobenzophenone, 3.5-5.5 parts of carbon disulfide, and 2.0-2.8 parts of NaOH. Alternatively, the raw materials for preparing the modified first monomer include the following components in parts by weight: 9.2 parts of benzidine, 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; The preparation method of the modified first monomer specifically comprises the following steps: A1. Dissolve p-phenylenediamine, ethylenediamine, or benzidine in toluene, introduce flowing nitrogen, and then add 4,4'-difluorobenzophenone. Mix thoroughly, then increase the temperature for continuous heating. After the reaction is complete, cool, purify, and dry to obtain a first monomer. A2. Dissolve the first monomer prepared in step A1 in an ethanol aqueous solution, add NaOH, mix thoroughly, add carbon disulfide dropwise, and continue the reaction. After the reaction is completed, precipitate with ice-cold anhydrous ether, filter, collect the solid, wash, and dry to obtain a modified first monomer.

2. The high-strength, wear-resistant composite special plastic according to claim 1, 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.

3. The high-strength, wear-resistant composite special plastic according to claim 2, characterized in that: In step A2, the ethanol aqueous solution is a mixed solution of ethanol and water, wherein the volume ratio of ethanol to water is 2-3:1; the reaction is carried out at room temperature, and the reaction time is controlled between 2-4 hours.

4. A method for preparing the high-strength, wear-resistant composite special plastic according to any one of claims 1 to 3, 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 conducting a first-order reaction. After the reaction is completed, continuously raising the temperature to conduct a second-order reaction. After the reaction, naturally cooling is carried out, deionized water is added, centrifugation is performed, and the precipitate is collected, washed, and dried to obtain a PEEK-based polymer; S2. Dissolve the PEEK-based polymer prepared in step S1 in NMP, adjust the pH to 4.5-5.5, increase the reaction temperature to 70-80° C., add zinc nitrate hexahydrate / ethanol solution dropwise, stir and react for 6-8 hours, cool, filter, collect the solid, and dry to obtain a Zn-doped PEEK-based polymer; S3. The Zn-doped PEEK-based polymer prepared in step S2 is subjected to ball milling treatment with polytetrafluoroethylene powder, and the mixture is placed on a flat vulcanizer. After demolding, a composite special plastic is obtained.

5. The method for preparing the high-strength, wear-resistant composite special plastic according to claim 4, characterized in that: In step S1, the volume ratio of toluene to sulfolane in the toluene / sulfolane mixed solution is 7-9:

10.

6. The method for preparing the high-strength, wear-resistant composite special plastic according to claim 5, 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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