A lubricating modified polymeric material, its preparation and use

Abstract

The application provides a lubrication modified polymer material and a preparation method and application thereof, and relates to the technical field of lubrication protection. The application provides a coating precursor solution, which comprises the following components in mass fraction: polysilazane 10-30 parts, small molecule lubricant 2-15 parts, nano active filler 2-15 parts, and solvent 55-90 parts; a high polymer material is immersed in the coating precursor solution for swelling, and the obtained swollen high polymer material is sequentially cleaned and solidified to obtain the lubrication modified polymer material. The application grafts a small molecule lubricant modified polysilazane coating on the surface of the high polymer material, the coating is closely combined with the high polymer substrate, the modified polysilazane can improve the surface hardness and surface lubrication performance of the material, and can effectively reduce the frictional resistance of the surface of the material. The coating of the lubrication modified polymer material prepared by the application has strong adhesion with the substrate, and has excellent lubrication and wear resistance.

Description

Technical Field

[0001] This invention relates to the field of lubrication and protection technology, and in particular to a lubrication-modified polymer material, its preparation method, and its application. Background Technology

[0002] Polymer materials are materials composed of high molecular weight compounds as a matrix, along with other additives. They mainly include three categories: plastics, synthetic rubber, and synthetic fibers. In recent years, polymer materials have been widely used in defense, aerospace, medical, transportation, construction, and mechanical and electronic fields. However, unlike hard metal materials, polymer contact surfaces are prone to wear, and the friction and wear process is complex. Therefore, improving the surface hardness of polymer elastomers, reducing surface elastic deformation, and reducing surface friction are of great significance.

[0003] Modifying polymer materials with hard coatings is an effective technical means to achieve the above objectives. Traditional coatings are usually physically bonded to the material surface through coating methods such as spraying and spin coating. Although they can reduce the surface friction coefficient to a certain extent, they usually have drawbacks such as poor adhesion and mismatch of mechanical properties, which cannot meet the needs of development. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a lubricating modified polymer material, its preparation method, and its application. The lubricating modified polymer material coating prepared by this invention has a tight bond with the substrate and exhibits excellent lubrication and wear resistance properties.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for preparing a lubricating modified polymer material, comprising the following steps:

[0007] A coating precursor solution is provided, the coating precursor solution comprising the following components in parts by weight: 10-30 parts of polysilazane, 2-15 parts of small molecule lubricant, 2-15 parts of nano-active filler, and 55-90 parts of solvent, wherein the small molecule lubricant contains hydroxyl groups;

[0008] The polymer material is immersed in the coating precursor solution to swell, thereby obtaining a swollen polymer material.

[0009] The swollen polymer was sequentially cleaned and cured to obtain the lubricating modified polymer material.

[0010] Preferably, the polysilazane comprises one or more of methyl polysilazane, vinyl polysilazane, fluorinated polysilazane, cyclic polysilazane, polyurea polysilazane, and perhydropolysilazane.

[0011] Preferably, the small molecule lubricant includes one or more of ethylene glycol, hexanediol, glycerol, cetyl alcohol, octadecyl alcohol, propylene glycol, isotretinoin, pentaerythritol, diethanolamine, 12-hydroxystearic acid, glyceryl distearate, glyceryl 1,3-stearic acid, triglyceride monostearate, and hydroxy ionic liquid.

[0012] Preferably, the hydroxyl ionic liquid comprises 1-(3′-hydroxypropyl)-3-octylimidazolium hexafluorophosphate ionic liquid, 1-(3′-hydroxypropyl)-3-octylimidazolium tetrafluoroborate ionic liquid, 1-(3′-hydroxypropyl)-3-hexylimidazolium hexafluorophosphate ionic liquid, 1-(3′-hydroxypropyl)-3-hexylimidazolium tetrafluoroborate ionic liquid, 1-(3′-hydroxypropyl)-3-butylimidazolium hexafluorophosphate ionic liquid, and 1-(3′-hydroxypropyl)-3-butylimidazolium tetrafluoroborate ionic liquid. One or more of the following: ionic liquid, 1-(2′-hydroxyethyl)-3-octylimidazolium hexafluorophosphate ionic liquid, 1-(2′-hydroxyethyl)-3-octylimidazolium tetrafluoroborate ionic liquid, 1-(2′-hydroxyethyl)-3-hexylimidazolium hexafluorophosphate ionic liquid, 1-(2′-hydroxyethyl)-3-hexylimidazolium tetrafluoroborate ionic liquid, 1-(2′-hydroxyethyl)-3-butylimidazolium hexafluorophosphate ionic liquid, and 1-(2′-hydroxyethyl)-3-butylimidazolium tetrafluoroborate ionic liquid.

[0013] Preferably, the nano-active filler includes one or more of alumina, zinc oxide, titanium dioxide, graphene, carbon nanofibers, silicon dioxide, silicon nitride, boron nitride, and zirconium oxide.

[0014] Preferably, the solvent includes one or more of acetone, dichloromethane, ethyl acetate, n-butyl ether, and tetrahydrofuran.

[0015] Preferably, the swelling temperature is room temperature and the time is 30 to 120 minutes.

[0016] Preferably, the curing temperature is room temperature and the curing time is 12 to 48 hours.

[0017] The present invention provides a lubricating modified polymer material prepared by the preparation method described above, comprising a polymer material and a lubricating coating bonded to the surface and subsurface of the polymer material, wherein the lubricating coating is a polysilazane-based coating grafted with a small molecule lubricant.

[0018] This invention provides the application of the lubrication-modified polymer materials described above in the field of lubrication, friction reduction, and protection.

[0019] This invention provides a method for preparing a lubricating modified polymer material, comprising the following steps: providing a coating precursor liquid, the coating precursor liquid comprising the following components in parts by mass: 10-30 parts of polysilazane, 2-15 parts of small molecule lubricant, 2-15 parts of nano-active filler, and 55-90 parts of solvent, wherein the small molecule lubricant contains hydroxyl groups; immersing a polymer material in the coating precursor liquid for swelling to obtain a swollen polymer; and sequentially cleaning and curing the swollen polymer to obtain the lubricating modified polymer material. The basic principle of this invention is as follows: The Si-H, Si-N, and NH bonds in polysilazane readily react with hydroxyl groups. Therefore, graft modification of polysilazane is achieved through a small-molecule lubricant containing hydroxyl groups, reducing its brittleness and improving its toughness. Furthermore, swelling drives the polysilazane and the small-molecule lubricant into the polymer network. During the alcoholysis reaction, the polysilazane forms a three-dimensional hard cross-linked network that entangles with the polymer network of the substrate, increasing the surface hardness of the polymer. Simultaneously, the introduction of the lubricant achieves lubrication modification of both the surface and subsurface. Compared with existing technologies, this invention has the following beneficial effects:

[0020] This invention, without altering the intrinsic structure and properties of the polymer material, grafts a polysilazane coating modified with small-molecule lubricants onto the surface and subsurface of the polymer material. This coating exhibits strong adhesion to the polymer substrate, and the modified polysilazane improves surface hardness and lubrication performance, effectively reducing surface friction. The lubricated modified polymer coating prepared by this invention demonstrates strong adhesion to the substrate and excellent lubrication and wear resistance. Furthermore, this invention is versatile and applicable to various polymer materials. In addition, the preparation process of this invention is simple. Detailed Implementation

[0021] This invention provides a method for preparing a lubricating modified polymer material, comprising the following steps:

[0022] A coating precursor solution is provided, the coating precursor solution comprising the following components in parts by weight: 10-30 parts of polysilazane, 2-15 parts of small molecule lubricant, 2-15 parts of nano-active filler, and 55-90 parts of solvent, wherein the small molecule lubricant contains hydroxyl groups;

[0023] The polymer material is immersed in the coating precursor solution to swell, thereby obtaining a swollen polymer material.

[0024] The swollen polymer was sequentially cleaned and cured to obtain the lubricating modified polymer material.

[0025] In this invention, unless otherwise specified, all raw materials involved are commercially available products well known in the art or prepared using preparation methods well known to those skilled in the art.

[0026] The present invention provides a coating precursor liquid, which comprises the following components in parts by weight: 10-30 parts of polysilazane, 2-15 parts of small molecule lubricant, 2-15 parts of nano-active filler, and 55-90 parts of solvent, wherein the small molecule lubricant contains hydroxyl groups.

[0027] In this invention, the coating precursor liquid comprises 10-30 parts, preferably 20-30 parts, of polysilazane by weight. In this invention, the polysilazane preferably comprises one or more of methyl polysilazane, vinyl polysilazane, fluorinated polysilazane, cyclic polysilazane, polyurea polysilazane, and perhydropolysilazane, more preferably methyl polysilazane; in the embodiments of this invention, the polysilazane is specifically organosilicon polysilazane IOTA OPSZ-9150.

[0028] Based on the mass fraction of the polysilazane, the coating precursor liquid comprises 2 to 15 parts of a small molecule lubricant, preferably 2 to 10 parts, and more preferably 5 to 6 parts. In this invention, the small molecule lubricant contains hydroxyl groups, which can be single or multiple. Preferably, the small molecule lubricant comprises one or more of ethylene glycol, hexanediol, glycerol, cetyl alcohol, octadecyl alcohol, propylene glycol, isotridecyl alcohol, pentaerythritol, diethanolamine, 12-hydroxystearic acid, distearate, glyceryl 1,3-stearate, triglyceride monostearate, and hydroxyl ionic liquids, more preferably glycerol, 12-hydroxystearic acid, or a hydroxyl ionic liquid. In this invention, the hydroxyl ionic liquid preferably includes 1-(3′-hydroxypropyl)-3-octylimidazolium hexafluorophosphate ionic liquid, 1-(3′-hydroxypropyl)-3-octylimidazolium tetrafluoroborate ionic liquid, 1-(3′-hydroxypropyl)-3-hexylimidazolium hexafluorophosphate ionic liquid, 1-(3′-hydroxypropyl)-3-hexylimidazolium tetrafluoroborate ionic liquid, 1-(3′-hydroxypropyl)-3-butylimidazolium hexafluorophosphate ionic liquid, and 1-(3′-hydroxypropyl)-3-butylimidazolium tetrafluoroborate. The invention comprises one or more of the following: salt ionic liquid, 1-(2′-hydroxyethyl)-3-octylimidazolium hexafluorophosphate ionic liquid, 1-(2′-hydroxyethyl)-3-octylimidazolium tetrafluoroborate ionic liquid, 1-(2′-hydroxyethyl)-3-hexylimidazolium hexafluorophosphate ionic liquid, 1-(2′-hydroxyethyl)-3-hexylimidazolium tetrafluoroborate ionic liquid, 1-(2′-hydroxyethyl)-3-butylimidazolium hexafluorophosphate ionic liquid, and 1-(2′-hydroxyethyl)-3-butylimidazolium tetrafluoroborate ionic liquid. In this invention, the small molecule lubricant exhibits excellent lubricating properties.

[0029] Polysilazanes are polymers with Si-N bonds as repeating units, soluble in various organic solvents. Therefore, the swelling of the polymer elastomer in a good solvent can drive the polysilazane to the surface and subsurface of the elastomer. Furthermore, cured polysilazane exhibits high hardness and good wear resistance, effectively reducing the viscous frictional resistance of the polymer elastomer and thus achieving a lubrication effect. However, a single polysilazane coating, after curing, suffers from high brittleness and is prone to cracking, with limited friction-reducing effect. This invention utilizes the reaction characteristics of the Si-N bonds in polysilazane with hydroxyl groups to graft a toughening small-molecule lubricant, effectively solving this problem. By using a small-molecule lubricant with lubricating properties, toughening is achieved while simultaneously providing lubrication.

[0030] Based on the mass fraction of the polysilazane, the coating precursor liquid includes 2 to 15 parts of nano-active filler, preferably 2 to 5 parts. In this invention, the nano-active filler preferably includes one or more of alumina, zinc oxide, titanium dioxide, graphene, carbon nanofibers, silicon dioxide, silicon nitride, boron nitride, and zirconium oxide. In this invention, the nano-active filler exhibits excellent wear resistance.

[0031] Based on the mass fraction of the polysilazane, the coating precursor liquid comprises 55-90 parts of solvent, preferably 60-70 parts. In this invention, the solvent preferably includes one or more of acetone, dichloromethane, ethyl acetate, n-butyl ether, and tetrahydrofuran.

[0032] In this invention, the coating precursor liquid is obtained by uniformly mixing all components.

[0033] After providing the coating precursor liquid, the present invention immerses the polymer material in the coating precursor liquid to swell, thereby obtaining the swollen polymer.

[0034] This invention does not have special requirements for the polymer material used; any polymer material well-known to those skilled in the art can be used, such as: polydimethylsiloxane (PDMS), nitrile rubber, ethylene propylene diene monomer (EPDM) rubber, polyurethane, etc.; thermoplastic polyurethane, polyethylene, polymethacrylate, polystyrene, etc.; and various engineering resins such as polyethylene terephthalate, polyetheretherketone, polyethersulfone, and polyphenylene sulfide. Before use, this invention preferably cleans the polymer material, preferably with ethanol and deionized water, respectively.

[0035] The present invention does not have any special requirements on the amount of the coating precursor liquid, as long as the polymer material is completely immersed.

[0036] In this invention, the swelling temperature is preferably room temperature, i.e., no additional heating or cooling is required, and the swelling time is preferably 30–120 min, specifically 30 min, 60 min, 90 min, or 120 min. In this invention, the swelling drives the polysilazane and small molecule lubricant into the molecular network of the polymer material. After swelling, the swollen polymer is removed from the coating precursor solution.

[0037] After obtaining the swollen polymer, the present invention sequentially cleans and cures the swollen polymer to obtain the lubricating modified polymer material. In the present invention, the cleaning reagent is preferably n-butyl ether or tetrahydrofuran, which removes unreacted monomers from the surface. In the present invention, the curing (surface drying) temperature is preferably room temperature, and the curing time is preferably 12–48 hours, specifically until complete curing. During the curing process, the polysilazane undergoes alcoholysis (the reaction between polysilazane and the hydroxyl groups of the small molecule lubricant is slow, and the alcoholysis reaction occurs during both the swelling and curing processes) and solidification, forming a hard network entangled with the polymer network of the substrate, resulting in a small molecule lubricant-modified polysilazane lubricating layer on the surface and subsurface of the polymer.

[0038] This invention develops a coating with excellent lubrication and wear resistance, based on polysilazane, using a swelling method. This invention modifies the surface of polymers through swelling with a good solvent; the method is simple, feasible, low-cost, and exhibits good adhesion, showing promising application prospects. Furthermore, introducing a new hard polymer coating based on swelling completely avoids the problems associated with coating modification through traditional coating methods. In addition, the selectivity of the good solvent endows this invention with versatility, making it applicable to various polymer materials.

[0039] This invention provides a lubricating modified polymer material prepared by the above-described preparation method, comprising a polymer material and a lubricating coating bonded to the surface and subsurface of the polymer material. The lubricating coating is a polysilazane coating grafted with a small-molecule lubricant. This invention introduces small-molecule lubricant-modified polysilazane onto the surface and subsurface of the polymer material via a swelling method. The resulting lubricating modified polymer material exhibits a low coefficient of friction (~0.15), excellent wear resistance, and good adhesion between the coating and the substrate.

[0040] This invention provides the application of the lubrication-modified polymer material described above in the field of lubrication, friction reduction, and protection. This invention does not impose any special requirements on the application method; any application method well-known to those skilled in the art can be used.

[0041] To further illustrate the present invention, the lubricating modified polymer materials, their preparation methods, and applications provided by the present invention are described in detail below with reference to examples, but these should not be construed as limiting the scope of protection of the present invention.

[0042] In each embodiment, the term "parts" refers to "parts by weight"; the polysilazane is organosilicon polysilazane IOTAOPSZ-9150, and the polydimethylsiloxane (PDMS) is Dow Corning PDMS Sylgard184.

[0043] Example 1

[0044] Prepare a solution containing 30 parts polysilazane, 5 parts glycerol, 2 parts nano alumina, and 63 parts n-butyl ether.

[0045] The surface of polydimethylsiloxane (PDMS) was cleaned with ethanol and deionized water, respectively. The cleaned PDMS was then immersed in the prepared solution. After swelling for 30 minutes, the PDMS sample was removed and the surface was cleaned with n-butyl ether. The sample was then placed in a room temperature environment for surface drying for 24 hours. The polysilazane was alcoholyzed and cured to obtain a modified polysilazane lubricating layer on the surface, thus obtaining a lubricated modified PDMS polymer material.

[0046] Example 2

[0047] Prepare a solution containing 30 parts polysilazane, 5 parts glycerol, 2 parts nano alumina, and 63 parts n-butyl ether.

[0048] The PDMS surface was cleaned with ethanol and deionized water respectively. The cleaned PDMS was then immersed in the prepared solution. After swelling for 60 minutes, the PDMS sample was removed and the surface was cleaned with n-butyl ether. The sample was then placed in a room temperature environment for surface drying for 24 hours. The polysilazane was alcoholyzed and cured to obtain a modified polysilazane lubricating layer on the surface, thus obtaining a lubricated modified PDMS polymer material.

[0049] Example 3

[0050] Prepare a solution containing 30 parts polysilazane, 5 parts glycerol, 2 parts nano alumina, and 63 parts n-butyl ether.

[0051] The PDMS surface was cleaned with ethanol and deionized water respectively. The cleaned PDMS was then immersed in the prepared solution. After swelling for 120 min, the PDMS sample was removed and the surface was cleaned with n-butyl ether. The sample was then placed in a room temperature environment for surface drying for 24 h. The polysilazane was alcoholyzed and cured to obtain a modified polysilazane lubricating layer on the surface, thus obtaining a lubricated modified PDMS polymer material.

[0052] Example 4

[0053] Prepare a solution containing 30 parts polysilazane, 6 parts 12-hydroxystearic acid, 2 parts nano-alumina, and 62 parts n-butyl ether.

[0054] The PDMS surface was cleaned with ethanol and deionized water respectively. The cleaned PDMS was then immersed in the prepared solution. After swelling for 120 min, the PDMS sample was removed and the surface was cleaned with n-butyl ether. The sample was then placed in a room temperature environment for surface drying for 24 h. The polysilazane was alcoholyzed and cured to obtain a modified polysilazane lubricating layer on the surface, thus obtaining a lubricated modified PDMS polymer material.

[0055] Example 5

[0056] Prepare a solution containing 30 parts polysilazane, 2 parts 1-(3′-hydroxypropyl)-3-octylimidazolium hexafluorophosphate ionic liquid, 2 parts nano-alumina, and 66 parts tetrahydrofuran.

[0057] The PDMS surface was cleaned with ethanol and deionized water respectively. The cleaned PDMS was then immersed in the prepared solution. After swelling for 120 min, the PDMS sample was removed and the surface was cleaned with n-butyl ether. The sample was then placed in a room temperature environment for surface drying for 24 h. The polysilazane was alcoholyzed and cured to obtain a modified polysilazane lubricating layer on the surface, thus obtaining a lubricated modified PDMS polymer material.

[0058] Example 6

[0059] To demonstrate the universality of the method of this invention, a polysilazane lubricating layer is controllably swollen on the surface of EPDM rubber. The specific steps are as follows:

[0060] Prepare a solution containing 30 parts polysilazane, 5 parts glycerol, 2 parts nano-alumina, and 63 parts tetrahydrofuran;

[0061] The surface of EPDM rubber was cleaned with ethanol and deionized water respectively. The cleaned EPDM rubber was then immersed in the prepared solution and swollen for 120 min. The sample was then removed and cleaned with tetrahydrofuran. The sample was then placed in a room temperature environment for curing for 48 h to obtain a EPDM rubber sample with surface grafted modified polysilazane.

[0062] The lubricating modified polymer materials of each embodiment were tested, including friction performance testing, surface hardness testing, and surface thickness testing. The testing methods are as follows:

[0063] Friction performance testing: The lubrication performance of the surface was evaluated using a traditional friction testing machine (CSM, Switzerland). The normal load was 1 N, the friction test pair was a steel ball (6 mm in diameter), the test method was a reciprocating mode (sliding distance of 5 mm), the sliding frequency was 1 Hz, and the test cycle was 180 times.

[0064] Surface hardness test: Surface modulus was tested using a nanoindenter (Bioindenter UNHT3 Bio, Anton Paar);

[0065] Surface thickness testing: The cross-sectional morphology was characterized using a field emission scanning electron microscope (JSM-6701F, JEOL Inc., Japan), and the subsurface layer thickness was measured.

[0066] The test results are shown in Table 1.

[0067] Table 1. Test results of lubricated modified polymer materials in each embodiment.

[0068]

[0069]

[0070] As can be seen from Table 1, in Examples 1-3, the thickness of the lubricating layer increases with the increase of swelling time, and the coefficient of friction first decreases and then increases. In Examples 3-5, different small molecule lubricants all have obvious lubricating effects. As can be seen from Example 6, this method is also applicable to other polymer substrates.

[0071] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a lubricating modified polymer material, characterized in that, Includes the following steps: A coating precursor solution is provided, the coating precursor solution comprising the following components in parts by weight: 10-30 parts of polysilazane, 2-15 parts of small molecule lubricant, 2-15 parts of nano-active filler, and 55-90 parts of solvent, wherein the small molecule lubricant contains hydroxyl groups; The polymer material is immersed in the coating precursor solution to swell, thereby obtaining a swollen polymer material. The swollen polymer was sequentially cleaned and cured to obtain the lubricating modified polymer material; The small molecule lubricant includes one or more of ethylene glycol, hexanediol, glycerol, hexadecyl alcohol, octadecyl alcohol, propylene glycol, isotretinoin, pentaerythritol, diethanolamine, 12-hydroxystearic acid, glyceryl distearate, glyceryl 1,3-stearic acid, polyglycerol monostearate, and hydroxyl ionic liquid; the hydroxyl ionic liquid includes 1-(3′-hydroxypropyl)-3-octylimidazolium hexafluorophosphate ionic liquid, 1-(3′-hydroxypropyl)-3-octylimidazolium tetrafluoroborate ionic liquid, 1-(3′-hydroxypropyl)-3-hexylimidazolium hexafluorophosphate ionic liquid, 1-(3′-hydroxypropyl)-3-hexylimidazolium tetrafluoroborate ionic liquid, 1 One or more of the following ionic liquids: 1-(3′-hydroxypropyl)-3-butylimidazolium hexafluorophosphate, 1-(3′-hydroxypropyl)-3-butylimidazolium tetrafluoroborate, 1-(2′-hydroxyethyl)-3-octylimidazolium hexafluorophosphate, 1-(2′-hydroxyethyl)-3-octylimidazolium tetrafluoroborate, 1-(2′-hydroxyethyl)-3-hexylimidazolium hexafluorophosphate, 1-(2′-hydroxyethyl)-3-hexylimidazolium tetrafluoroborate, 1-(2′-hydroxyethyl)-3-butylimidazolium hexafluorophosphate, and 1-(2′-hydroxyethyl)-3-butylimidazolium tetrafluoroborate; The nano-active filler includes one or more of alumina, zinc oxide, titanium dioxide, graphene, carbon nanofibers, silicon dioxide, silicon nitride, boron nitride, and zirconium oxide.

2. The preparation method according to claim 1, characterized in that, The polysilazane includes one or more of methyl polysilazane, vinyl polysilazane, fluorinated polysilazane, cyclic polysilazane, polyurea polysilazane, and perhydropolysilazane.

3. The preparation method according to claim 1, characterized in that, The solvent includes one or more of acetone, dichloromethane, ethyl acetate, n-butyl ether, and tetrahydrofuran.

4. The preparation method according to claim 1, characterized in that, The swelling temperature is room temperature, and the time is 30~120 minutes.

5. The preparation method according to claim 1, characterized in that, The curing temperature is room temperature, and the time is 12~48h.

6. The lubricating modified polymer material prepared by the preparation method according to any one of claims 1 to 5 comprises a polymer material and a lubricating coating bonded to the surface and subsurface of the polymer material, wherein the lubricating coating is a polysilazane-based coating grafted with a small molecule lubricant.

7. The application of the lubrication-modified polymer material according to claim 6 in the field of lubrication, friction reduction and protection.

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