Preparation method of molybdenum disulfide nanosheet / polytetrafluoroethylene composite filament

Abstract

The invention discloses a preparation method of molybdenum disulfide nanosheet / polytetrafluoroethylene composite filaments. According to the method, the molybdenum disulfide nanosheet / polytetrafluoroethylene composite filaments are prepared from a polytetrafluoroethylene matrix and uniformly dispersed molybdenum disulfide nanosheets through extrusion molding, degreasing, calendering film forming, secondary drafting, stretching after cutting, twisting and shaping. Compared with pure PTFE filaments, the molybdenum disulfide nanosheet / polytetrafluoroethylene composite filaments obtained by the method have the advantages that the friction coefficient is obviously reduced, the wear-resistant life is prolonged, and the molybdenum disulfide nanosheet / polytetrafluoroethylene composite filaments have excellent strength and high-temperature resistance. According to the composite filament prepared by the method, the application field of the PTFE filament is widened.

Description

Technical Field

[0001] The invention belongs to the technical field of new material processing, and specifically relates to a method for preparing molybdenum disulfide nanosheets / polytetrafluoroethylene composite filaments. Background Art

[0002] Polytetrafluoroethylene has excellent chemical inertness and corrosion resistance, low friction coefficient, excellent thermal stability and high insulation performance, and is widely used in high temperature heat resistance, corrosion resistance, lubrication and electrical insulation. Polytetrafluoroethylene is processed into yarn. Due to its flexible and spinnable properties, it can be processed into fabrics or non-woven textiles and is widely used in high temperature flue gas filtration.

[0003] Pure PTFE filaments have good mechanical properties, but they are prone to "cold flow" and are easily worn during high loads or dynamic friction, which to a certain extent limits the wider application of polytetrafluoroethylene materials. In the field of wear-resistant materials that require a lower friction coefficient, pure polytetrafluoroethylene filaments under the existing technology cannot meet the actual extreme environment requirements. Molybdenum disulfide nano has a layered structure, and its crystals are hexagonal. Due to the weak binding force of S atoms between molybdenum disulfide layers, it is easy to slide and exhibits excellent friction reduction effects, high compressive strength, good wear resistance, strong adhesion, and low friction coefficient. The particle size of molybdenum disulfide nanosheets is smaller, and its adhesion and coverage are higher, and its anti-wear and friction reduction properties are better. The existing technology coats molybdenum disulfide on the surface of polytetrafluoroethylene. Due to the low surface energy of polytetrafluoroethylene, the adhesion fastness and life are not ideal.

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for effectively combining molybdenum disulfide and polytetrafluoroethylene to manufacture molybdenum disulfide nanosheets / polytetrafluoroethylene composite filaments. The filaments and fabrics obtained by the method have good self-lubrication, good strength, high wear resistance and high temperature resistance. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing molybdenum disulfide nanosheets / polytetrafluoroethylene composite filaments in view of the deficiencies of the prior art. The composite filaments obtained by the method have good self-lubrication, high strength, high wear resistance and high temperature resistance.

[0006] The object of the present invention is achieved in the following ways:

[0007] A method for preparing a molybdenum disulfide nanosheet / polytetrafluoroethylene composite filament, comprising a polytetrafluoroethylene (PTFE) matrix and uniformly dispersed molybdenum disulfide nanosheets (MoS 2 ) is obtained by extrusion molding, degreasing, calendering film forming, two-pass drawing, stretching after cutting, and twisting and shaping.

[0008] The above-mentioned MoS2 nanosheet / polytetrafluoroethylene composite filament preparation process specifically includes the following steps:

[0009] (1) dispersing the molybdenum disulfide nanosheets in aviation kerosene at high speed using a high-speed homogenizer, so that the molybdenum disulfide nanosheets and the aviation kerosene form a uniform molybdenum disulfide nanosheet / aviation kerosene mixed system suspension;

[0010] (2) stirring and mixing the PTFE dispersed resin powder and the molybdenum disulfide nanosheet / aviation kerosene mixed system at a low speed to form a uniform mixture; the mass ratio of the PTFE dispersed resin powder, the molybdenum disulfide nanosheet and the aviation kerosene is 4:0.3 to 0.5:1;

[0011] (3) Extruding the mixed material into a rod-shaped material;

[0012] (4) removing aviation kerosene from the rod-shaped material obtained in step (3) at high temperature to obtain a defatted rod;

[0013] (5) The degreased rod prepared in step (4) is subjected to calendering to form a film; the temperature is 250-280° C., the film thickness is 0.1-0.3 mm, and the rolling pressure is 8-12 MPa;

[0014] (6) The calendered film prepared in step (5) is subjected to two-pass stretching on a stretching machine to obtain a stretched film: the first-pass stretching ratio is 2:1-3:1, the temperature is 260-280° C., and the second-pass stretching ratio is 1.4:1-1.8:1, the temperature is 270-280° C.;

[0015] (7) The drawn film prepared in step (6) is cut on a film splitting machine, the film is split into a plurality of filaments, and further stretched, with a drawing ratio of 1.2:1 to 1.5:1 and a temperature of 270 to 280° C., to form continuous composite filaments;

[0016] (8) The composite filament prepared in step (7) is twisted and shaped, and then wound to obtain the molybdenum disulfide nanosheet / polytetrafluoroethylene composite filament.

[0017] Preferably, in step (1), the speed of the high-speed homogenizer is 10000-15000 rpm, and the dispersion time is 10-15 min. The setting of the speed and time avoids the agglomeration of nano-molybdenum disulfide in aviation kerosene, and prevents the uniformity of subsequent dispersion from being affected.

[0018] Preferably, the low-speed stirring condition is 500-1000 rpm for 40-60 min. 2 If the stirring speed of the nanosheet / jet fuel mixture is too low, it will be unfavorable for dispersion. If the stirring speed is too high and exceeds the range, the crystallinity of the dispersed resin will change significantly, which is not conducive to the subsequent calendering and stretching.

[0019] Preferably, the temperature for removing the aviation kerosene in step (4) is 310-330° C. If the temperature for removing the kerosene is too high, the material may be thermally damaged due to overheating.

[0020] Preferably, in step (8), the setting temperature is 320-330°C and the twist is 300-380 twists / m. If the setting temperature is too low, it is difficult to set the filaments, and the temperature cannot be too high, as the material is soft and easily over-stretched, resulting in uneven thickness.

[0021] Preferably, the extrusion molding adopts a plunger extruder with a pressure of 60-66 kg, an extrusion temperature of 50-60° C., an extrusion compression ratio of 150:1, a cone angle of 30 degrees, and an aspect ratio of 5. The preferred pressure is 60-63 kg.

[0022] In the above method, if the first stretching ratio is not selected appropriately, the film thickness will be thick, which will cause a great burden on the subsequent drawing and slicing. Only within the appropriate stretching ratio range, it is conducive to stretching and thinning, and at the same time, it is conducive to the uniform dispersion of rice disulfide nanosheets.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] (1) The molybdenum disulfide nanosheet / polytetrafluoroethylene composite filament obtained by the method of the present invention has a significantly lower friction coefficient than that of pure PTFE filament, an improved wear resistance life, and excellent strength and high temperature resistance.

[0025] (2) The pressure used for extrusion of a general polytetrafluoroethylene dispersion resin and kerosene mixed system is about 70 kg. However, the present invention uses a certain amount of molybdenum disulfide nanosheets to improve the lubrication effect of a single aviation kerosene, reduce the extrusion pressure, reduce the mixing time, and save energy. 2 Uniform dispersion and orientation regulation. Therefore, a certain amount of MoS2 nanosheets are added to synergize the lubrication and anti-friction effect of aviation kerosene on polytetrafluoroethylene dispersion resin.

[0026] (3) The composite filaments prepared by the method of the present invention broaden the application fields of PTFE filaments, such as being used as high-temperature dust filter materials, abrasive belt base fabric materials, anti-friction lubricating materials, and high-temperature self-cleaning materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0028] Figure 1 Molybdenum disulfide nanosheet / polytetrafluoroethylene composite filament according to the embodiment of the present invention

[0029] In the figure, 1 is a molybdenum disulfide nanosheet and 2 is polytetrafluoroethylene. DETAILED DESCRIPTION

[0030] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0031] Among them, PTFE dispersed resin powder was purchased from Shandong Dongyue Chemical Co., Ltd., and molybdenum disulfide nanosheets were purchased from Manli Nano Technology (Ningbo) Co., Ltd.

[0032] Embodiment 1:

[0033] The preparation method of molybdenum disulfide nanosheet / polytetrafluoroethylene composite filament is as follows:

[0034] (1) MoS2 nanosheets are dispersed in aviation kerosene by a high-speed homogenizer, so that the MoS2 nanosheets and the aviation kerosene form a uniform and stable suspension, the speed of the high-speed homogenizer is 10000 rpm, and the time is 10 min;

[0035] (2) The PTFE dispersed resin powder and the molybdenum disulfide nanosheet / jet fuel mixture are stirred at a low speed to form a uniform mixture; the mass ratio of the PTFE dispersed resin powder, molybdenum disulfide nanosheet and jet fuel is 4:0.3:1, the stirring speed is 500 rpm, and the stirring time is 40 min.

[0036] (3) Disperse PTFE resin powder\MoS 2 Nanosheet / jet fuel mixture is extruded into rod-shaped material. The extrusion molding adopts a plunger extruder with a pressure of 60 kg, an extrusion temperature of 50°C, an extrusion compression ratio of 150:1, a cone angle of 30°, and an aspect ratio of 5.

[0037] (4) The rod-shaped material obtained in step (3) is placed in an oven at high temperature to remove the aviation kerosene to obtain a defatted rod. The oven temperature for removing the aviation kerosene is set at 310° C. for 2 hours.

[0038] (5) The degreased rod prepared in step (4) enters a calender for calendering to form a film: the material is calendered into a film at 250° C. on a double-roll calender, with a film thickness of 0.1 mm and a rolling pressure of 8 MPa.

[0039] (6) The calendered film prepared in step (5) is further subjected to two-pass stretching on a stretching machine: the first pass stretching ratio is 2:1, the temperature is 260°C, and the second pass stretching ratio is 1.4:1, the temperature is 270°C.

[0040] (7) The drawn film prepared in step (6) is cut on a film splitting machine, and the film is split into a plurality of filaments, and further stretched with a drawing ratio of 1.2:1 and a temperature of 270° C. to form continuous molybdenum disulfide nanosheets / polytetrafluoroethylene composite filaments.

[0041] (8) The molybdenum disulfide nanosheet / polytetrafluoroethylene composite filament prepared in step (7) is twisted and shaped on a twisting machine at a setting temperature of 320° C. and a twist of 300 twists / m, and then the molybdenum disulfide nanosheet / polytetrafluoroethylene composite filament is obtained by winding.

[0042] Embodiment 2:

[0043] The preparation method of molybdenum disulfide nanosheet / polytetrafluoroethylene composite filament is as follows:

[0044] (1) MoS2 nanosheets are dispersed in aviation kerosene by a high-speed homogenizer, so that the MoS2 nanosheets and the aviation kerosene form a uniform and stable suspension, the speed of the high-speed homogenizer is 13000 rpm, and the time is 13 min;

[0045] (2) The PTFE dispersed resin powder and the molybdenum disulfide nanosheet / jet fuel mixture are stirred at a low speed to form a uniform mixture; the mass ratio of the PTFE dispersed resin powder, molybdenum disulfide nanosheet and jet fuel is 4:0.4:1, and the stirring is carried out at a low speed (800 rpm) for 50 minutes.

[0046] (3) Disperse PTFE resin powder\MoS 2 The nanosheet / jet fuel mixed system is extruded into rod-shaped materials. The extrusion molding adopts a plunger extruder with a pressure of 63 kg, an extrusion temperature of 55°C, an extrusion compression ratio of 150:1, a cone angle of 30°, and an aspect ratio of 5.

[0047] (4) The rod-shaped material obtained in step (3) is placed in an oven to remove the aviation kerosene at high temperature. The oven temperature is set at 320°C for 2 hours to obtain a degreased PTFE dispersed resin powder\MoS 2 Nanosheet hybrid rods;

[0048] (5) The degreased mixed rod prepared in step (4) is subjected to calendering to form a film: the material is calendered into a film at 260° C. on a double-roll calender, with a film thickness of 0.2 mm and a rolling pressure of 10 MPa.

[0049] (6) The calendered film prepared in step (5) is further subjected to two-pass stretching on a stretching machine: the first pass stretching ratio is 2.5:1, the temperature is 270°C, and the second pass stretching ratio is 1.6:1, the temperature is 275°C.

[0050] (7) The drawn film prepared in step (6) is cut on a film splitting machine, and the film is split into a plurality of filaments, and further stretched with a drawing ratio of 1.3:1 and a temperature of 275° C. to form continuous molybdenum disulfide nanosheets / polytetrafluoroethylene composite filaments.

[0051] (8) The molybdenum disulfide nanosheet / polytetrafluoroethylene composite filament prepared in step (7) is twisted and shaped on a twisting machine at a setting temperature of 325° C. and a twist of 340 twists / m, and then the molybdenum disulfide nanosheet / polytetrafluoroethylene composite filament is obtained by winding.

[0052] Embodiment 3:

[0053] The preparation method of molybdenum disulfide nanosheet / polytetrafluoroethylene composite filament is as follows:

[0054] (1) dispersing the molybdenum disulfide nanosheets in aviation kerosene using a high-speed homogenizer to form a uniform and stable suspension of the molybdenum disulfide nanosheets and the aviation kerosene, the speed of the high-speed homogenizer being 15000 rpm, and the time being 15 min;

[0055] (2) The PTFE dispersed resin powder and the molybdenum disulfide nanosheet / jet fuel mixture are stirred at a low speed to form a uniform mixture; the PTFE dispersed resin powder, molybdenum disulfide nanosheet and jet fuel are mixed in a mass ratio of 4:0.5:1 and stirred at a low speed (1000 rpm) for 60 minutes.

[0056] (3) Disperse PTFE resin powder\MoS 2 Nanosheet / jet fuel mixture is extruded into rod-shaped material. The extrusion molding adopts a plunger extruder with a pressure of 60 kg, an extrusion temperature of 50°C, an extrusion compression ratio of 150:1, a cone angle of 30°, and an aspect ratio of 5.

[0057] (4) The rod-shaped material obtained in step (3) is placed in an oven at high temperature to remove the aviation kerosene to obtain a defatted rod. The temperature of the oven is set at 330° C. for 2 hours to remove the aviation kerosene.

[0058] (5) The degreased rod prepared in step (4) enters a calender for calendering to form a film: the material is calendered into a film at 280° C. on a double-roll calender with a film thickness of 0.3 mm and a rolling pressure of 12 MPa.

[0059] (6) The calendered film prepared in step (5) is further subjected to two-pass stretching on a stretching machine: the first pass stretching ratio is 3:1, the temperature is 280°C, and the second pass stretching ratio is 1.8:1, the temperature is 280°C.

[0060] (7) The stretched film prepared in step (6) is cut on a film splitting machine, and the film is split into a plurality of filaments, and further stretched with a stretching ratio of 1.5:1 and a temperature of 280° C. to form continuous molybdenum disulfide nanosheets / polytetrafluoroethylene composite filaments.

[0061] (8) The molybdenum disulfide nanosheet / polytetrafluoroethylene composite filament prepared in step (7) is twisted and shaped on a twisting machine at a setting temperature of 330° C. and a twist of 380 twists / m, and then the molybdenum disulfide nanosheet / polytetrafluoroethylene composite filament is obtained by winding.

[0062] Product quality test results:

[0063] According to GB / T10006-2021 Determination of friction coefficient of plastic film and sheet, GB / T 3960-2016 Test method for sliding friction and wear of plastics, and GB / T 35748-2017 Polytetrafluoroethylene filament, the quality tests of the materials of the embodiments of the present invention and commercially available PTFE filaments were carried out, and the results are shown in Table 1.

[0064] Table 1

[0065]

Claims

1. A method for preparing molybdenum disulfide nanosheets / polytetrafluoroethylene composite filaments, characterized in that The method comprises the following steps: extruding a polytetrafluoroethylene matrix and uniformly dispersed molybdenum disulfide nanosheets, degreasing, calendering to form a film, two-pass drafting, stretching after cutting, and twisting to form a film.

2. The preparation method according to claim 1, characterized in that The method comprises the following steps: (1) dispersing the molybdenum disulfide nanosheets in aviation kerosene at high speed using a high-speed homogenizer, so that the molybdenum disulfide nanosheets and the aviation kerosene form a uniform molybdenum disulfide nanosheet / aviation kerosene mixed system; (2) stirring and mixing the PTFE dispersed resin powder and the molybdenum disulfide nanosheet / aviation kerosene mixed system at a low speed to form a uniform mixture; the mass ratio of the PTFE dispersed resin powder, the molybdenum disulfide nanosheet and the aviation kerosene is 4:0.3 to 0.5:1; (3) Extruding the mixed material into a rod-shaped material; (4) removing aviation kerosene from the rod-shaped material obtained in step (3) at high temperature to obtain a defatted rod; (5) The degreased rod prepared in step (4) is subjected to calendering to form a film; the temperature is 250-280° C., the film thickness is 0.1-0.3 mm, and the rolling pressure is 8-12 MPa; (6) The calendered film prepared in step (5) is subjected to two-pass stretching on a stretching machine to obtain a stretched film: the first-pass stretching ratio is 2:1-3:1, the temperature is 260-280° C., and the second-pass stretching ratio is 1.4:1-1.8:1, the temperature is 270-280° C.; (7) The drawn film prepared in step (6) is cut on a film splitting machine, the film is split into a plurality of filaments, and further stretched, with a drawing ratio of 1.2:1 to 1.5:1 and a temperature of 270 to 280° C., to form continuous composite filaments; (8) The composite filament prepared in step (7) is twisted and shaped, and then wound to obtain the molybdenum disulfide nanosheet / polytetrafluoroethylene composite filament.

3. The preparation method according to claim 2, characterized in that In the step (1), the speed of the high-speed homogenizer is 10000-15000 rpm, and the time is 10-15 minutes.

4. The preparation method according to claim 2, characterized in that The low-speed stirring condition in step (2) is 500-1000 rpm low-speed stirring for 40-60 min.

5. The preparation method according to claim 2, characterized in that The temperature for removing the aviation kerosene in the step (4) is 310-330°C.

6. The preparation method according to claim 2, characterized in that In the step (8), the setting temperature is 320-330° C. and the twist is 300-380 twists / m.

7. The preparation method according to claim 2, characterized in that The extrusion molding in the step (3) adopts a plunger extruder with a pressure of 60-66 kg, an extrusion temperature of 50-60°C, an extrusion compression ratio of 150:1, a cone angle of 30°, and an aspect ratio of 5.

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