Polyamide s-triazine polymer, preparation method thereof and solid lubricating composite material

Abstract

The invention discloses a polyamide-s-triazine polymer, a preparation method thereof and a solid lubrication composite material, and belongs to the field of high polymer materials, melamine is used as a core, and is condensed with an amide compound containing secondary amine to obtain an amide-s-triazine monomer. Carrying out condensation on the monomer and a cross-linking agent containing diacyl chloride or triacyl chloride, and carrying out preliminary cross-linking on a polymer molecular chain to prepare polyamide s-triazine prepolymer powder; and carrying out suspension polymerization on the prepolymer to obtain the polyamide s-triazine polymer. The polymer and polytetrafluoroethylene are subjected to hot pressing to obtain the polyamide-s-triazine solid lubricating composite material, and the material has the properties of high modulus and high bearing capacity. Results of a compression test and a UMT test show that the polyamide-s-triazine solid lubrication composite material has very high strength and good lubricity, the strength and the lubricity of the polyamide-s-triazine solid lubrication composite material are obviously higher than those of melamine formaldehyde resin and nylon materials in the market, and the polyamide-s-triazine solid lubrication composite material can be used as a lubrication medium material for lubrication under a heavy load working condition.

Description

Technical Field

[0001] The invention relates to a polyamide s-triazine polymer and a preparation method thereof and a solid lubricating composite material, belonging to the field of polymer materials. Background Art

[0002] The loss of materials and energy caused by friction and wear of mechanical components has gradually become an economic problem for various industrial sectors. Therefore, lubricating materials have become a rigid material for industrial production. In some extreme working conditions, such as high pressure, high load, and corrosive environment, mechanical wear is extremely serious, and people are in urgent need of a self-lubricating material with good performance.

[0003] Polytetrafluoroethylene is a solid material with excellent lubricity. This is because its molecular chain surface is covered with a layer of highly polar fluorine elements, which makes its surface energy low, inert, and easy to form a lubricating layer in the friction pair for relative sliding. However, polytetrafluoroethylene has poor mechanical properties and needs to be attached to a strong carrier to work in extreme environments.

[0004] Melamine resin has the advantages of high hardness and good water resistance due to its unique triazine structure, making it very suitable as a carrier material for polytetrafluoroethylene. However, melamine is brittle and not flexible. Summary of the invention

[0005] In order to overcome the deficiencies of the prior art, the present invention provides a polyamide-s-triazine polymer and a preparation method thereof, which has the advantages of high hardness and good water resistance of the triazine structure and high toughness, and provides a solid lubricating composite material using the polyamide-s-triazine polymer.

[0006] The technical solution adopted by the present invention to solve its technical problem is: In a first aspect, the present application provides a polyamide-s-triazine polymer, comprising a structural unit R shown in structural formula 1, a structural unit P shown in structural formula 2, and a main chain segment Q connected between the structural unit R and the structural unit P shown in structural formula 3; Structural formula 1; Structural formula 2; Structural formula 3; Among them, m in structural formula 2 is 2 or 3, A is an alkyl group with a carbon number of less than 12 or an aryl group with a carbon number of less than 18; *1 in structural formula 3 is connected to *1 in structural formula 2 by a single bond, and *2 in structural formula 3 is connected to *2 in structural formula 1 by a single bond.

[0007] The polyamide-s-triazine polymer provided in the present application has good flexibility while maintaining the high strength performance of melamine resin.

[0008] Furthermore, the molar ratio of the structural unit R, the structural unit P, and the main chain segment Q is 10:2-5:10.

[0009] In a second aspect, the present application provides a method for preparing a polyamide-s-triazine polymer, comprising the following steps: Methyl amination of 2-bromomethyl-ethyl acrylate to obtain ethyl 2-(aminomethyl)methyl-acrylate; The amino group of 2-(aminomethyl)methyl-ethyl-acrylate is connected with a Boc-protecting group to obtain 2-(tert-butyl formate aminomethyl)methyl-ethyl-acrylate; Hydrolysis of ethyl 2-(tert-butylformylaminomethyl)methyl-acrylate to obtain 2-(tert-butylformylaminomethyl)methyl-acrylate; Taking melamine and 2-(tert-butyl formate aminomethyl)methyl-acrylic acid to undergo amidation reaction to obtain 1,3,5-triazine-2,4,6-tris(2-(tert-butyl formate aminomethyl)methyl-acrylamide); Removing the Boc-protecting group of 1,3,5-triazine-2,4,6-tris(2-(tert-butyl formate aminomethyl)methyl-acrylamide) to obtain the monomer 1,3,5-triazine-2,4,6-tris(2-(aminomethyl)methyl-acrylamide); Taking a cross-linking agent containing diacyl chloride or triacyl chloride and polycondensing the monomer to obtain a prepolymer; The prepolymer is subjected to addition polymerization to obtain the polyamide-s-triazine polymer.

[0010] The method introduces a polyamide material with high strength and good toughness into the melamine resin through chemical grafting, thereby giving the melamine resin good flexibility while maintaining its high strength performance.

[0011] In a third aspect, the present application provides a solid lubricating composite material, which is formed by mixing polytetrafluoroethylene and the polyamide-s-triazine polymer described in the first aspect and then hot-pressing them.

[0012] Furthermore, the mass ratio of the polytetrafluoroethylene and the polyamide-s-triazine polymer is 1-6:3.

[0013] The beneficial effects of the present invention are as follows: the composite material of the present invention contains triazine functional groups and amide functional groups, and the degree of crosslinking is increased by condensation crosslinking, thereby having high modulus and high load-bearing performance. The results of compression tests and UMT tests show that the polyamide-s-triazine solid lubricating composite material has very high strength and good lubricity, and its strength and lubricity are significantly stronger than those of melamine formaldehyde resin and nylon materials on the market, and can be used as a lubricating medium material for lubrication under heavy load conditions.

[0014] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or understood by practicing the present application. The purpose and other advantages of the present application can be realized and obtained by the structures particularly pointed out in the written description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a comparison chart of the compression strength test results of Example 6, Comparative Example 1, Comparative Example 2, and Comparative Example 3.

[0016] Figure 2 It is a comparison chart of the lubricity test results of Example 6, Comparative Example 1, Comparative Example 2, and Comparative Example 3. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure is clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] It should be understood that, under the premise of no conflict, any and all embodiments of the present invention can be combined with the technical features in any other embodiment or multiple other embodiments to obtain another embodiment. The present invention includes such a combination to obtain another embodiment.

[0019] In this specification, groups and substituents thereof can be selected by those skilled in the art to provide stable structural moieties and compounds. When substituents are described by conventional chemical formulas written from left to right, the substituents also include chemically equivalent substituents obtained when the structural formula is written from right to left.

[0020] Unless otherwise specified, all technical and scientific terms used herein have the standard meaning in the field to which the claimed subject matter belongs. If there are multiple definitions for a term, the definition herein shall prevail.

[0021] The embodiment of the present application first synthesizes a monomer molecule with melamine as the core, multiple secondary amine end groups, and multiple double bonds, including the following steps.

[0022] Synthesis of 2-(aminomethyl)methyl-ethyl acrylate: Take methylamine hydrochloride and sodium ethoxide (EtONa) respectively, add them to dichloromethane, stir at 25°C to make methylamine hydrochloride enter the free state; then, cool the system to -10°C±5°C, add triethylamine (Et3N) and dichloromethane solution of 2-bromomethyl-ethyl acrylate in sequence, and start the methylation reaction; after the methylation is completed, add 10 wt.% citric acid aqueous solution to quench the reaction and wash, separate and collect the organic phase, concentrate and remove the solvent, and obtain the crude product of 2-(aminomethyl)methyl-ethyl acrylate. The reaction equation is shown in Reaction Formula 1.

[0023] Reaction 1 Synthesis of 2-(tert-butyl formate aminomethyl)methyl-ethyl acrylate: Take the crude product of 2-(aminomethyl)methyl-ethyl acrylate and triethylamine (Et3N), add them to dichloromethane, stir to dissolve, and cool to 0℃~10℃; then, slowly add Boc-anhydride (Boc2O, di-tert-butyl dicarbonate) to the system to react the Boc protecting group on the amine; after the reaction is completed (after obtaining enough target product), add 10 wt.% citric acid aqueous solution to quench the reaction and wash, separate and collect the organic phase, concentrate and remove the solvent, and obtain the crude product of 2-(tert-butyl formate aminomethyl)methyl-ethyl acrylate. The reaction equation is shown in Reaction Equation 2.

[0024] Reaction 2 Synthesis of 2-(tert-butylaminomethyl formate)methyl-acrylic acid: Take the crude product of ethyl 2-(tert-butylaminomethyl formate)methyl-acrylic acid, add it to anhydrous ethanol, stir and dissolve; add 10 wt.% NaOH aqueous solution to the system, stir at 25°C, and start ester hydrolysis reaction; after the hydrolysis is completed, filter the system, collect the filter cake, and add the filter cake to 10 wt.% citric acid aqueous solution, stir to form a citric acid dispersion; use ethyl acetate to extract the citric acid dispersion multiple times, separate and collect the organic phase; at 25°C, add the organic phase to n-heptane, stir and crystallize, filter and collect the filter cake, and place the filter cake in an oven at 80°C to dry, thereby obtaining a solid powder of 2-(tert-butylaminomethyl formate)methyl-acrylic acid. The reaction equation is shown in Reaction Formula 3.

[0025] Reaction 3 Synthesis of 1,3,5-triazine-2,4,6-tris(2-(tert-butylcarboxylate methyl)methyl-acrylamide): solid powder of 2-(tert-butylcarboxylate methyl)methyl-acrylamide and CDI (N,N'-carbonyldiimidazole) were added to DMF (N,N-dimethylformamide) respectively, and stirred and dispersed; DMF solution of melamine was added, and the temperature was raised to 60°C under stirring to start the amidation reaction; after the amidation, the system was cooled naturally and poured into deionized water for washing to form an aqueous phase; the aqueous phase was extracted with ethyl acetate for multiple times, and the organic phase was separated and collected, and the organic phase was concentrated, and after removing most of the ethyl acetate, it was added to n-hexane, stirred for crystallization, and the filter cake was collected by filtration; the filter cake was placed in a 60°C oven and dried to obtain solid particles of 1,3,5-triazine-2,4,6-tris(2-(tert-butylcarboxylate methyl)methyl-acrylamide). The reaction equation is shown in Reaction Formula 4.

[0026] Reaction 4 Synthesis of 1,3,5-triazine-2,4,6-tris(2-(aminomethyl)methyl-acrylamide): solid particles of 1,3,5-triazine-2,4,6-tris(2-(tert-butyl formate aminomethyl)methyl-acrylamide) are added to anhydrous ethanol and stirred to dissolve; a 1 mol / L hydrogen chloride ethyl acetate solution is added to the system, the temperature is raised to 40°C under stirring, and the Boc-protecting group removal reaction is started; after the Boc-protection group removal is completed, the system is filtered and the filter cake is collected, the filter cake is added to a 10 wt.% NaHCO3 aqueous solution for washing, and the filter cake is filtered and collected; the filter cake is placed in a 60°C oven and dried to obtain the 1,3,5-triazine-2,4,6-tris(2-(aminomethyl)methyl-acrylamide) product. The reaction equation is shown in Reaction Equation 5.

[0027] Reaction 5 At this point, the target monomer has been obtained, and then it is further polycondensed with a crosslinking agent containing diacyl chloride or triacyl chloride to form a prepolymer. Preferably, the crosslinking agent does not contain olefinic bonds or acetylenic bonds, so as to avoid excessive polymerization during free radical polymerization, making it difficult to control the process and generating bubbles.

[0028] Take 1,3,5-triazine-2,4,6-tris(2-(aminomethyl)methyl-acrylamide) and add it to isopropyl acetate, stir and disperse, cool to -30°C to form a cyclohexane isopropyl acetate dispersion; control the temperature at -30±5°C, and slowly add the condensation crosslinking agent to the isopropyl acetate dispersion.

[0029] If the cross-linking agent is trimesoyl chloride, the reaction process is as shown in Reaction Formula 6.

[0030] Reaction 6 in, It is 1,3,5-triazine-2,4,6-tris(2-(aminomethyl)methyl-acrylamide), and the circled R is the structural unit R; It is a condensation polymer molecular chain.

[0031] If the cross-linking agent is 4-4'-diacyl chloride diphenyl ether, the reaction process is as shown in Reaction Scheme 7.

[0032] Reaction 7 At this point, a prepolymer has been obtained, the monomer has a trifunctional group in the polycondensation reaction, and the crosslinking agent has a difunctional group or a trifunctional group in the polycondensation reaction, so the prepolymer has a preliminary crosslinking network. Next, polyaddition opens the double bonds to obtain a polyamide-s-triazine polymer.

[0033] Specifically, after the acylation is completed, the isopropyl acetate dispersion system is temperature controlled to 10°C, deionized water and emulsifier (one of Tween-60, Span-80, or a mixture thereof) are added, and the dispersion is stirred; then, the system is heated to 65°C, and the initiator benzoyl peroxide is added dropwise to start the suspension polymerization reaction. After the suspension polymerization is completed, the system is naturally warmed up, poured into ethanol for washing, filtered and the filter cake is collected, and the filter cake is dried to obtain polyamide melamine amide particles (polyamide s-triazine polymer).

[0034] The polyamide-s-triazine polymer thus obtained has a structural unit R shown in structural formula 1, a structural unit P shown in structural formula 2, and a main chain segment Q connected between the structural unit R and the structural unit P shown in structural formula 3; Structural formula 1; Structural formula 2; Structural formula 3; Among them, m in structural formula 2 is 2 or 3, A is an alkyl group with a carbon number of less than 12 or an aryl group with a carbon number of less than 18; *1 in structural formula 3 is connected to *1 in structural formula 2 by a single bond, and *2 in structural formula 3 is connected to *2 in structural formula 1 by a single bond.

[0035] Finally, the polyamide-s-triazine polymer is hot-pressed with polytetrafluoroethylene resin to obtain a solid lubricating composite material.

[0036] Specifically, the polyamide melamine amide particles are sieved, mixed with polytetrafluoroethylene powder, and poured into a mold; the mold is placed in a flat vulcanizer and hot-pressed to obtain a polyamide melamine amide solid lubricant material (solid lubricant composite material).

[0037] The composite material contains triazine functional groups and amide functional groups, and the degree of crosslinking is increased by a condensation crosslinking agent, thereby giving it high modulus and high load-bearing properties. Specifically, melamine is used as the core and condensed with an amide compound containing a secondary amine to obtain an amide s-triazine monomer. Then, the monomer is condensed with a crosslinking agent containing diacyl chloride or triacyl chloride, and the polymer molecular chain is initially crosslinked to prepare a polyamide s-triazine powder. Polyamide s-triazine is compounded with polytetrafluoroethylene and hot-pressed to obtain a polyamide s-triazine solid lubricating composite material.

[0038] Synthesis example 1 Provided is a method for preparing ethyl 2-(aminomethyl)methyl-acrylate, comprising the following steps: (1) Weigh 50 g of methylamine hydrochloride and 40 g of sodium ethoxide respectively, add them into 200 ml of dichloromethane, stir until dissolved, cool the system to -10°C, and add 60 g of triethylamine to the system.

[0039] (2) Weigh 100 g of 2-bromomethyl-ethyl acrylate and add it to 200 ml of dichloromethane. Stir until dissolved to form a solution. Then, control the temperature at -10±5°C and slowly add the dichloromethane solution of 2-bromomethyl-ethyl acrylate. Continue stirring at -10±5°C for 2 hours.

[0040] (3) Control the temperature at 10 °C and slowly add 200 ml~300 ml of 10 wt.% citric acid aqueous solution until the pH of the system is between 6 and 7 as measured by pH paper. Continue stirring for 30 minutes.

[0041] (4) The organic phase was separated and collected, and the solvent was removed by concentration to obtain a crude product liquid of 2-(aminomethyl)methyl-acrylic acid ethyl ester.

[0042] Synthesis example 2 Provided is a method for preparing ethyl 2-(tert-butyl formate aminomethyl)methyl-acrylate, comprising the following steps: (1) Weigh 100 g of the crude product liquid of ethyl 2-(aminomethyl)methyl-acrylate obtained in Synthesis Example 1 and 60 g of triethylamine, add them to 200 ml of dichloromethane, stir until dissolved, and cool to 10°C.

[0043] (2) Weigh 150 g of Boc-anhydride and add it to 300 ml of dichloromethane to prepare a Boc-anhydride solution. Then, control the temperature at 0°C~10°C, slowly add the Boc-anhydride solution, and continue stirring for 2 hours.

[0044] (3) Keep the temperature below 25 °C and slowly add 200-300 ml of 10 wt.% citric acid aqueous solution until the pH of the system is between 6 and 7 as measured by pH paper.

[0045] (4) The organic phase was separated and collected, and the solvent was removed by concentration to obtain a crude product liquid of 2-(tert-butylcarboxamidomethyl)methyl-acrylate ethyl ester.

[0046] Synthesis example 3 Provided is a method for preparing 2-(tert-butyl formate aminomethyl)methacrylic acid, comprising the following steps: (1) Weigh 150 g of the crude product liquid of 2-(tert-butyl formate aminomethyl)methyl-acrylate obtained in Synthesis Example 2, add it to 500 ml of anhydrous ethanol, and stir at 25°C to dissolve; (2) Add 400 ml of 10 wt.% NaOH aqueous solution to the system of step (1) and stir at 25°C for 6 hours.

[0047] (3) Filter the system of step (2) and collect the filter cake; then, add the filter cake to 300 ml of 10 wt.% citric acid aqueous solution and stir to form a citric acid aqueous phase.

[0048] (4) Add 50 g of NaCl particles to the citric acid aqueous phase and stir to disperse; then, add 400 ml of ethyl acetate to the citric acid and stir to extract the citric acid aqueous phase, separate and collect the organic phase. Repeat the above extraction operation three times and combine the organic phases.

[0049] (5) Concentrate the organic phase from step (4) to 200 ml. Add the concentrated organic phase to 500 ml of n-heptane at 25°C to allow the system to crystallize product particles, and continue stirring for 1 hour.

[0050] (6) Filter the system of step (5), collect the filter cake, and dry the filter cake in an oven at 80° C. to obtain solid particles of 2-(tert-butylcarbamate methyl)methacrylic acid.

[0051] Synthesis example 4 Provided is a method for preparing 1,3,5-triazine-2,4,6-tris(2-(tert-butyl formate aminomethyl)methyl-acrylamide), comprising the following steps: (1) Weigh 110 g of the solid particles of 2-(tert-butylcarboxamidomethyl)methacrylic acid prepared in Synthesis Example 3 and 90 g of carbonyl diimidazole (CDI) into 200 ml of DMF and stir until dissolved.

[0052] (2) Weigh 20 g of melamine, add it to 50 ml of DMF, stir until dissolved, and prepare a solution; add the melamine DMF solution to the system of step (1), heat to 60°C, and continue stirring for 4 hours.

[0053] (3) The system in step (2) was naturally cooled to 25° C.; then, the system was poured into 500 ml of deionized water while stirring to form an aqueous phase.

[0054] (4) Add 500 ml of ethyl acetate to the aqueous phase in step (3), stir to extract the aqueous phase, separate and collect the organic phase. Repeat the above extraction operation three times and combine the organic phases.

[0055] (5) Concentrate the organic phase from step (4) to 200 ml. Add the concentrated organic phase to 500 ml of n-hexane at 25°C to allow the system to crystallize product particles, and continue stirring for 1 hour.

[0056] (6) Filter the system of step (5), collect the filter cake, and dry the filter cake in an oven at 80° C. to obtain a solid powder of 1,3,5-triazine-2,4,6-tris(2-(tert-butylcarboxylateaminomethyl)methyl-acrylamide).

[0057] Synthesis example 5 A method for preparing 1,3,5-triazine-2,4,6-tris(2-(aminomethyl)methyl-acrylamide) is provided, comprising the following steps: (1) Weigh 100 g of the solid powder of 1,3,5-triazine-2,4,6-tris(2-(tert-butylcarboxylateaminomethyl)methyl-acrylamide) obtained in Synthesis Example 4, add it to 250 ml of anhydrous ethanol, and stir to dissolve.

[0058] (2) Add 100 ml of 1 mol / L hydrogen chloride in ethyl acetate to the system of step (1), heat the system to 40°C, and continue stirring for 4 hours.

[0059] (3) The system of step (2) is cooled naturally; then the system is filtered and the filter cake is collected, and the filter cake is added to 200 ml of 10 wt.% NaHCO3 aqueous solution for washing, and stirred to form a sodium bicarbonate aqueous phase.

[0060] (4) Filter the sodium bicarbonate aqueous phase of step (3), wash the filter cake with deionized water and ethyl acetate in turn, collect the filter cake, place the filter cake in a 60° C. oven, and dry it to obtain 1,3,5-triazine-2,4,6-tris(2-(aminomethyl)methyl-acrylamide) product.

[0061] Example 6 Provided is a method for preparing a polyamide-melamine solid lubricating material (solid lubricating composite material), comprising the following steps: (1) Weigh 10 g of 1,3,5-triazine-2,4,6-tris(2-(aminomethyl)methyl-acrylamide) obtained in Synthesis Example 5, add it to 40 ml of isopropyl acetate, stir and disperse it, and cool the system to -30°C.

[0062] (2) Weigh 1.5 g of 1,3,5-trimethylbenzene chloride and dissolve it in 10 ml of isopropyl acetate to prepare a 1,3,5-trimethylbenzene chloride solution. Then, slowly add the 1,3,5-trimethylbenzene chloride solution dropwise to the system in step (1) at -30±5°C and continue the reaction for 3 hours.

[0063] (3) Weigh 2 g of Tween-60 and add it to 150 ml of deionized water, stir and disperse to form an aqueous dispersion. Then, control the temperature of the system in step (2) to 10°C and slowly pour it into the above aqueous dispersion, stir and disperse.

[0064] (4) The system of step (3) was heated to 65°C, 100 mg of benzoyl peroxide (BPO) was added dropwise thereto, and stirring was continued for 10 hours.

[0065] (5) The system of step (4) was naturally warmed to 25°C, poured into 400 ml of ethanol, stirred and dispersed, filtered and the filter cake was collected, and the filter cake was placed in an oven at 80°C for drying to obtain a polyamide melamine solid.

[0066] (6) The solid dried in step (5) is crushed and sieved to obtain polyamide melamine powder. 10 g of polyamide melamine powder and 25 g of polytetrafluoroethylene dispersion are weighed in sequence, added to 100 ml of ethanol, stirred, centrifuged and the sediment is collected.

[0067] (7) The sediment from step (6) is dried and then filled into a mold.

[0068] (8) The mold of step (7) is placed in a flat vulcanizer, and the temperature is set to 70°C, the pressure is 5 MPa, and the holding time is 3 hours for preliminary molding; then, the temperature is raised to 150°C and the pressure is held for 3 hours; the sample is allowed to cool naturally to room temperature to obtain a polyamide melamine solid lubricant material with self-lubricating properties.

[0069] Example 7 Provided is a method for preparing a polyamide melamine solid lubricating material, comprising the following steps: (1) Weigh 10 g of 1,3,5-triazine-2,4,6-tris(2-(aminomethyl)methyl-acrylamide) obtained in Synthesis Example 5, add it to 40 ml of isopropyl acetate, stir and disperse it, and cool the system to -30°C.

[0070] (2) Weigh 3 g of 4,4-chloroformylphenyl ether (DEDC) and dissolve it in 15 ml of isopropyl acetate to prepare a DEDC solution. Then, slowly add the DEDC solution dropwise to the system in step (1) at -30±5°C and continue the reaction for 3 hours.

[0071] (3) Weigh 2 g of Tween-60 and add it to 150 ml of deionized water, stir and disperse to form an aqueous dispersion. Then, control the temperature of the system in step (2) to 10°C and slowly pour it into the above aqueous dispersion, stir and disperse.

[0072] (4) The system of step (3) was heated to 65°C, 100 mg of benzoyl peroxide (BPO) was added dropwise thereto, and stirring was continued for 10 hours.

[0073] (5) The system of step (4) was naturally warmed to 25°C, poured into 400 ml of ethanol, stirred and dispersed, filtered and the filter cake was collected, and the filter cake was placed in an oven at 80°C for drying to obtain a polyamide melamine solid.

[0074] (6) The solid dried in step (5) is crushed and sieved to obtain polyamide melamine powder. 10 g of polyamide melamine powder and 25 g of polytetrafluoroethylene dispersion are weighed in sequence, added to 100 ml of ethanol, stirred, centrifuged and the sediment is collected.

[0075] (7) The sediment from step (6) is dried and then filled into a mold.

[0076] (8) The mold of step (7) is placed in a flat vulcanizer, and the temperature is set to 70°C, the pressure is 5 MPa, and the holding time is 3 hours for preliminary molding; then, the temperature is raised to 150°C and the pressure is held for 3 hours; the sample is allowed to cool naturally to room temperature to obtain a polyamide melamine solid lubricant material with self-lubricating properties.

[0077] Comparative Example 1 A method for preparing a non-polycondensed and cross-linked solid lubricating material is provided, comprising the following steps: (1) Weigh 35 g of 1,3,5-triazine-2,4,6-tris(2-(aminomethyl)methyl-acrylamide) obtained in Synthesis Example 5, add it to 50 ml of isopropyl acetate, and stir to disperse it. Stir at 25°C.

[0078] (2) Weigh 2 g of Tween-60 and add it to 150 ml of deionized water, stir and disperse to form an aqueous dispersion. Then, pour the system in step (1) into the above aqueous dispersion and stir and disperse.

[0079] (3) The system of step (2) was heated to 65°C, 100 mg of benzoyl peroxide (BPO) was added dropwise thereto, and stirring was continued for 10 hours.

[0080] (4) The system of step (3) was naturally warmed to 25°C, poured into 400 ml of ethanol, stirred and dispersed, filtered and the filter cake was collected, and the filter cake was placed in an oven at 80°C for drying to obtain a polyamide melamine solid.

[0081] (5) The solid dried in step (4) is crushed and sieved to obtain an addition polymer powder. 10 g of the addition polymer powder and 25 g of polytetrafluoroethylene dispersion are weighed in sequence, added to 100 ml of ethanol, stirred, centrifuged and the sediment collected.

[0082] (6) The sediment from step (5) is dried and then filled into a mold.

[0083] (7) The mold of step (6) is placed in a flat vulcanizer, and the temperature is set to 70°C, the pressure is 5 MPa, and the heat preservation time is 3 hours for preliminary molding; then, the temperature is raised to 150°C and the pressure is maintained for 3 hours; the sample is allowed to cool naturally to room temperature to obtain the solid lubricating material of comparative example 1.

[0084] Comparative Example 2 Provided is a method for preparing a melamine formaldehyde resin having self-lubricating properties, comprising the following steps: (1) Take 15 g of melamine formaldehyde molding compound (melamine powder) and 25 g of polytetrafluoroethylene dispersion, add them to ethanol, stir, centrifuge and collect the sediment.

[0085] (2) The sediment from step (1) is dried and then filled into a mold.

[0086] (3) Placing the mold of step (2) in a flat vulcanizer, setting the temperature to 70°C, the pressure to 5 MPa, and the holding time to 3 hours for preliminary molding; then, raising the temperature to 150°C and holding the pressure for 3 hours; allowing the sample to cool naturally to room temperature to obtain a melamine formaldehyde resin with self-lubricating properties.

[0087] Comparative Example 3 Provided is a method for preparing a PA66 resin having self-lubricating properties, comprising the following steps: (1) Take 15 g PA66 powder and 25 g polytetrafluoroethylene dispersion, add them to ethanol, stir, centrifuge and collect the sediment.

[0088] (2) The sediment from step (1) is dried and then filled into a mold.

[0089] (3) The mold of step (2) is placed in a flat vulcanizer, and the temperature is set to 70°C, the pressure is 5 MPa, and the heat preservation time is 3 hours for preliminary molding; then, the temperature is raised to 180°C and the pressure is maintained for 3 hours; the sample is allowed to cool naturally to room temperature to obtain a PA66 resin with self-lubricating properties.

[0090] Performance evaluation: The performance test and evaluation of the self-lubricating materials prepared in Examples 6-7 and Comparative Examples 1-3 were conducted. The lubricity of the materials was tested by a reciprocating friction and wear tester. The test parameters were set as follows: the load was 20 N, the linear speed was 36 mm / s, and the test time was 1 hour. Some of the results are shown in Table 1. Figure 2 The wear rate was measured by white light interferometer. The compressive strength was tested by universal testing machine. Some of the results are shown in Figure 1 All test results are shown in Table 1.

[0091] Table 1 Example 6 Example 7 Comparative Example 1 Comparative Example 2 Comparative Example 3 Friction coefficient 0.014 0.016 0.015 0.021 0.018 <![CDATA[Wear rate / x10 -5 mm / N.m]]> 7.2 11.3 19.7 47.9 20.1 Compression strength / MPa 171.5 166.3 146.5 126.2 120.7 The results in Table 1 show that the lubricity and wear rate of the melamine formaldehyde resin in Comparative Example 2 are not as good as those of the nylon material in Comparative Example 3. This is mainly because melamine has no toughness. In the later stage of the test, the sample cracked obviously. Figure 2 It shows that the friction coefficient increases sharply in the later period (after 3400s) of comparative example 2. The compression test results show that the compression strength of comparative example 1 is better than that of comparative examples 2 and 3, which is mainly due to the combination of the rigidity of melamine and the toughness of amide.

[0092] The results in Table 1 show that the lubricity of the sample polymerized using the monomer prepared in Synthesis Example 5 is better than that of Comparative Examples 2 and 3, and the compressive strengths of Examples 6 and 7 are significantly better than those of Comparative Examples 1 to 3. This result shows that the strength of the polyamide melamine resin is significantly increased after cross-linking, and the increase in strength and modulus is beneficial to the stability of the resin in friction motion.

[0093] In the description of this specification, the description with reference to the terms "one embodiment", "certain embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0094] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A polyamide-s-triazine polymer, characterized in that: It includes a structural unit R shown in structural formula 1, a structural unit P shown in structural formula 2, and a main chain segment Q connected between the structural unit R and the structural unit P shown in structural formula 3; Structural formula 1; Structural formula 2; Structural formula 3; Among them, m in structural formula 2 is 2 or 3, A is an alkyl group with a carbon number of less than 12 or an aryl group with a carbon number of less than 18; *1 in structural formula 3 is connected to *1 in structural formula 2 by a single bond, and *2 in structural formula 3 is connected to *2 in structural formula 1 by a single bond.

2. A method for preparing a polyamide-s-triazine polymer, characterized in that: The following steps are involved: Methyl amination of 2-bromomethyl-ethyl acrylate to obtain ethyl 2-(aminomethyl)methyl-acrylate; The amino group of 2-(aminomethyl)methyl-ethyl-acrylate is connected with a Boc-protecting group to obtain 2-(tert-butyl formate aminomethyl)methyl-ethyl-acrylate; Hydrolysis of ethyl 2-(tert-butylformylaminomethyl)methyl-acrylate to obtain 2-(tert-butylformylaminomethyl)methyl-acrylate; Taking melamine and 2-(tert-butyl formate aminomethyl)methyl-acrylic acid to undergo amidation reaction to obtain 1,3,5-triazine-2,4,6-tris(2-(tert-butyl formate aminomethyl)methyl-acrylamide); Removing the Boc-protecting group of 1,3,5-triazine-2,4,6-tris(2-(tert-butyl formate aminomethyl)methyl-acrylamide) to obtain the monomer 1,3,5-triazine-2,4,6-tris(2-(aminomethyl)methyl-acrylamide); Taking a cross-linking agent containing diacyl chloride or triacyl chloride and polycondensing the monomer to obtain a prepolymer; The prepolymer is subjected to addition polymerization to obtain the polyamide-s-triazine polymer.

3. The method for preparing a polyamide-s-triazine polymer according to claim 2, characterized in that: The step of methylating 2-bromomethyl-acrylate to obtain 2-(aminomethyl)methyl-acrylate comprises: Disperse methylamine hydrochloride and sodium ethoxide in dichloromethane, cool to -10°C ± 5°C, then add triethylamine and dichloromethane solution of 2-bromomethyl-ethyl acrylate in sequence to carry out methylamination reaction; add citric acid aqueous solution to quench the reaction and wash, separate and collect the organic phase, and concentrate to remove dichloromethane to obtain 2-(aminomethyl)methyl-ethyl acrylate.

4. The method for preparing a polyamide-s-triazine polymer according to claim 2, characterized in that: The step of connecting the amino group of 2-(aminomethyl)methyl-ethyl acrylate to a Boc-protecting group to obtain 2-(tert-butyl formate aminomethyl)methyl-ethyl acrylate comprises: Take 2-(aminomethyl)methyl-ethyl acrylate and triethylamine and disperse them in dichloromethane, cool them to 0℃~10℃, add Boc-anhydride to react; add citric acid aqueous solution to quench the reaction and wash, separate and collect the organic phase, concentrate to remove dichloromethane, and obtain 2-(tert-butyl formate aminomethyl)methyl-ethyl acrylate.

5. The method for preparing a polyamide-s-triazine polymer according to claim 2, characterized in that: The step of hydrolyzing ethyl 2-(tert-butyl formate aminomethyl)methyl-acrylate to obtain 2-(tert-butyl formate aminomethyl)methyl-acrylate comprises: Take 2-(tert-butyl formate aminomethyl)methyl-ethyl-acrylate and dissolve it in anhydrous ethanol, and add a NaOH aqueous solution; after the hydrolysis is completed, filter, disperse the filter residue in a citric acid aqueous solution, use ethyl acetate to extract the citric acid dispersion, separate the liquids and collect the organic phase; add the organic phase into n-heptane, stir and crystallize, filter, and dry the filter residue to obtain a solid powder of 2-(tert-butyl formate aminomethyl)methyl-acrylic acid.

6. The method for preparing a polyamide-s-triazine polymer according to claim 2, characterized in that: The step of subjecting melamine to amidation reaction with 2-(tert-butyl formate aminomethyl)methyl-acrylic acid to obtain 1,3,5-triazine-2,4,6-tris(2-(tert-butyl formate aminomethyl)methyl-acrylamide) comprises: 2-(tert-butyl formate aminomethyl)methyl-acrylic acid and N,N'-carbonyldiimidazole were dispersed in N,N-dimethylformamide respectively, and a solution of melamine in N,N-dimethylformamide was added, and the temperature was raised to 60°C under stirring to cause an amidation reaction; after the amidation reaction was completed, the temperature was naturally lowered, and the aqueous phase was extracted with ethyl acetate after washing, and the organic phase was collected and concentrated, and then added to n-hexane and stirred for crystallization, filtered, and the filter residue was dried to obtain solid particles of 1,3,5-triazine-2,4,6-tris(2-(tert-butyl formate aminomethyl)methyl-acrylamide).

7. The method for preparing a polyamide-s-triazine polymer according to claim 2, characterized in that: The step of removing the Boc-protecting group of 1,3,5-triazine-2,4,6-tris(2-(tert-butyl formate aminomethyl)methyl-acrylamide) to obtain the monomer 1,3,5-triazine-2,4,6-tris(2-(aminomethyl)methyl-acrylamide) comprises: Take 1,3,5-triazine-2,4,6-tris(2-(tert-butyl formate aminomethyl)methyl-acrylamide) and dissolve it in anhydrous ethanol, add a solution of hydrogen chloride in ethyl acetate, and heat it to 40°C under stirring to start the reaction of removing the Boc-protecting group; after the reaction, wash with a NaHCO3 aqueous solution and filter, and dry the filter residue to obtain 1,3,5-triazine-2,4,6-tris(2-(aminomethyl)methyl-acrylamide).

8. The method for preparing a polyamide-s-triazine polymer according to claim 2, characterized in that: The step of polycondensing the crosslinking agent containing diacyl chloride or triacyl chloride with the monomer to obtain the prepolymer comprises: The monomer is dispersed in isopropyl acetate, the temperature is controlled at -30±5°C, the cross-linking agent is added dropwise, and the prepolymer system is obtained by reaction.

9. The method for preparing a polyamide-s-triazine polymer according to claim 8, characterized in that: The step of initiating addition polymerization of the prepolymer to obtain the polyamide-s-triazine polymer comprises: The prepolymer system is temperature controlled to 10° C., deionized water and an emulsifier are added, stirred and dispersed, and then the system is heated to 65° C., an initiator is added dropwise, and a suspension polymerization reaction is carried out; after the reaction is completed, the system is cooled naturally, poured into ethanol for washing, filtered, and the filter residue is dried to obtain the polyamide s-triazine polymer.

10. A solid lubricating composite material, characterized in that: The polytetrafluoroethylene and the polyamide-s-triazine polymer according to claim 1 are mixed and then hot-pressed.

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