PTFE glass fiber and preparation method thereof

Abstract

The invention provides a PTFE glass fiber and a preparation method thereof, and the preparation method comprises the following steps: carrying out desizing treatment on a high-strength alkali-free glass fiber, soaking in an acid solution, and carrying out surface etching; the preparation method comprises the following steps: dissolving perfluorosilane in an organic solvent to prepare a solution with the mass concentration of 1%-5%, adding the surface-activated high-strength alkali-free glass fiber into the perfluorosilane solution, stirring and reacting at 60-80 DEG C for 1-3 hours, filtering, washing with a solvent, and drying; adding the perfluorosilane modified high-strength alkali-free glass fiber into a pre-prepared polymer precursor solution, and carrying out heat treatment at 150-350 DEG C; adding the polymer-coated high-strength alkali-free glass fiber into a pre-prepared nano material dispersion liquid, and carrying out ultrasonic treatment; the preparation method comprises the following steps: mixing polytetrafluoroethylene resin, surface-modified high-strength alkali-free glass fiber, a lubricating phase and a wetting dispersant according to a mass ratio of (60-75): (25-40): (3-7): (0.5-1.5), carrying out compression molding, sintering, and cooling to room temperature to obtain the PTFE glass fiber. The PTFE glass fiber prepared by the invention has excellent water permeation resistance and mechanical properties.

Description

Technical Field

[0001] The invention relates to a glass fiber and a preparation method thereof, in particular to a PTFE glass fiber and a preparation method thereof, belonging to the technical field of polymer composite materials. Background Art

[0002] In order to improve the mechanical properties of polytetrafluoroethylene (PTFE), a filling and modification method is often used to prepare composite materials, such as glass fiber filled PTFE composite materials, which are low in cost, easy to process, and have significantly improved mechanical properties. However, traditional PTFE glass fiber composite materials are easily permeable to water, and the interface bonding between glass fiber and PTFE matrix is ​​poor, and poor composite materials show obvious phase separation.

[0003] Although studies have shown that the use of high-strength alkali-free glass fibers can improve the water-proof performance of PTFE glass fiber composites to a certain extent, this is because compared with ordinary glass fibers, high-strength alkali-free glass fibers have lower alkali content and higher mechanical strength, which can reduce the probability of water molecules penetrating through the fiber-matrix interface. However, using only high-strength alkali-free glass fibers as fillers has limited improvement in the water-proof performance of composite materials and cannot fundamentally solve the interface bonding problem. Summary of the invention

[0004] Based on the above background, the purpose of the present invention is to provide a method for preparing PTFE glass fiber to solve the problems described in the background technology.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] A method for preparing PTFE glass fiber, the method comprising the following steps:

[0007] The high-strength alkali-free glass fiber is subjected to high-temperature treatment for desizing, and the desizing high-strength alkali-free glass fiber is immersed in an acid solution, reacted at 40 to 60° C. for 1 to 3 hours for surface etching, and the etched high-strength alkali-free glass fiber is washed with deionized water to neutrality, and dried to obtain a surface-activated high-strength alkali-free glass fiber;

[0008] The perfluorosilane is dissolved in an organic solvent to prepare a solution with a mass concentration of 1% to 5%, the surface activated high-strength alkali-free glass fiber is added to the perfluorosilane solution, stirred and reacted at 60 to 80° C. for 1 to 3 hours, filtered, washed with a solvent, and dried to obtain the perfluorosilane-modified high-strength alkali-free glass fiber;

[0009] The perfluorosilane-modified high-strength alkali-free glass fiber is added to a pre-prepared polymer precursor solution, and then filtered, washed, dried, and heat-treated at 150-350° C. to obtain a polymer-coated high-strength alkali-free glass fiber;

[0010] The high-strength alkali-free glass fiber coated with a polymer is added to a pre-prepared nanomaterial dispersion, subjected to ultrasonic treatment for 30 to 60 minutes, filtered, washed, and dried after stirring to obtain a surface-modified high-strength alkali-free glass fiber;

[0011] The polytetrafluoroethylene resin, the surface-modified high-strength alkali-free glass fiber, the lubricating phase and the wetting dispersant are mixed in a mass ratio of 60-75:25-40:3-7:0.5-1.5, the mixed material is put into a mold, and the mold is pressed at a pressure of 25-40 MPa to obtain a composite material blank, and the composite material blank is put into an oven, sintered and then cooled to room temperature to obtain PTFE glass fiber.

[0012] Through multi-layer surface modification, a continuous barrier is formed on the surface of the glass fiber, which prevents water molecules from approaching and penetrating from the physical structure. The perfluorosilane modification treatment introduces highly hydrophobic fluorocarbon chains (-CF2-CF2-), which are similar to the molecular structure of the PTFE matrix, forming a synergistic hydrophobic effect. The nanomaterial modification layer further blocks the possible water molecule penetration channels by filling the interface micropores and gaps. At the same time, each interface layer is well combined with the matrix and greatly reduces the formation of interface micro-gaps. These factors lead to the obtained PTFE glass fiber having excellent anti-permeability. At the same time, the preparation method solves the problem of poor interface bonding between the two by establishing a strong and tough interface transition layer from the glass fiber to the PTFE matrix. First, a microscopic rough structure is formed on the surface of the glass fiber by etching with an acidic solution, which increases the specific surface area and provides a mechanical anchoring basis. The subsequent perfluorosilane modification treatment forms a key chemical bridging layer, which is firmly combined with the glass fiber through a silicon-oxygen bond (-Si-O-), and its fluorocarbon chain has a strong affinity with PTFE. The polymer coating treatment alleviates the stiffness difference between the hard glass fiber and the relatively soft PTFE matrix, preventing interface failure caused by stress concentration. The final nanomaterial modification treatment forms a three-dimensional interface structure, providing additional anchor points and further enhancing the interface bonding strength.

[0013] Preferably, the high-strength alkali-free glass fiber has a mesh size of 800 to 1500 meshes, an average particle size of 3 to 15 μm, and an aspect ratio of 10 to 20:1.

[0014] Preferably, the acidic solution is a dilute sulfuric acid solution, a dilute hydrochloric acid solution or a mixed solution thereof with a mass concentration of 0.05 to 0.5 mol / L.

[0015] Preferably, the polymer precursor solution is a solution prepared by dissolving polyamic acid in N,N-dimethylformamide with a mass concentration of 10%, or a solution prepared by dissolving polyetheretherketone in dichloromethane with a mass concentration of 8%.

[0016] Preferably, the nanomaterial dispersion is a dispersion of aluminum oxide nanoparticles with an average particle size of 50 nm dispersed in ethanol with a mass concentration of 1%, or a dispersion of carbon nanotubes dispersed in N,N-dimethylformamide with a mass concentration of 0.5%.

[0017] Preferably, the lubricating phase is selected from one or more of molybdenum disulfide, graphite and tungsten disulfide.

[0018] Preferably, the wetting and dispersing agent is selected from one or more of stearic acid, sodium dodecyl sulfate and sodium dodecylbenzene sulfonate.

[0019] Preferably, the sintering step specifically includes: heating from room temperature to 250°C at a rate of 2-5°C / min, and keeping warm for 30 minutes; then heating to 350-380°C at a rate of 1-3°C / min, and keeping warm for 30-120 minutes; then cooling to 250°C at a rate of 1-3°C / min, and then cooling to room temperature by natural cooling.

[0020] A PTFE glass fiber prepared by adopting the above-mentioned preparation method of PTFE glass fiber.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] The invention discloses a preparation method of PTFE glass fiber. By performing surface activation and surface modification treatment on high-strength alkali-free glass fiber, the problems of easy water penetration and poor interface bonding existing in conventional glass fiber-filled PTFE composite materials are solved. The surface treatment method combining acid solution etching activation, perfluorosilane treatment, polymer coating and nano material modification not only improves the surface activity of glass fiber, but also improves the interface bonding with PTFE matrix, and forms a strong and tough interface transition layer. The PTFE glass fiber prepared by the preparation method of PTFE glass fiber has a water absorption rate of ≤0.02%, a tensile strength of ≥24MPa, an elongation at break of ≥215%, a friction coefficient of 0.06-0.10, and has excellent water-proof performance and mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0024] Figure 1 It is a schematic flow chart of a method for preparing PTFE glass fiber of the present invention;

[0025] Figure 2 This is a SEM image (60.0 μm) of the PTFE glass fiber prepared in Example 1 of the present invention after being immersed in water. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is further described in detail below through specific embodiments and in conjunction with the accompanying drawings. It should be understood that the implementation of the present invention is not limited to the following embodiments, and any form of modification and / or change made to the present invention will fall within the protection scope of the present invention.

[0027] In the present invention, unless otherwise specified, all parts and percentages are weight units, and the equipment and raw materials used can be purchased from the market or are commonly used in the art. The methods in the following embodiments, unless otherwise specified, are conventional methods in the art. The components or equipment in the following embodiments, unless otherwise specified, are universal standard parts or components known to those skilled in the art, and their structures and principles are known to those skilled in the art through technical manuals or conventional experimental methods.

[0028] The present invention discloses a method for preparing PTFE glass fiber. Figure 1 As shown, the method includes the following steps: surface activation treatment - perfluorosilane modification treatment - polymer coating treatment - nanomaterial modification treatment - mixing - pressing - sintering. The specific steps are as follows:

[0029] The high-strength alkali-free glass fiber is placed in a muffle furnace at 350-450° C. for high-temperature treatment for 2-4 hours to perform desizing treatment; the desizing high-strength alkali-free glass fiber is immersed in an acid solution, and reacted at 40-60° C. for 1-3 hours to perform surface etching; the etched high-strength alkali-free glass fiber is washed with deionized water to neutrality, and then dried at 80-120° C. for 4-12 hours to obtain a surface-activated high-strength alkali-free glass fiber;

[0030] The perfluorosilane is dissolved in an organic solvent to prepare a solution with a mass concentration of 1% to 5%; the surface-activated high-strength alkali-free glass fiber is added to the perfluorosilane solution, and stirred for reaction at 60 to 80° C. for 1 to 3 hours; after filtering, the solution is washed with a solvent, and then dried at 100 to 150° C. for 2 to 6 hours to obtain a perfluorosilane-modified high-strength alkali-free glass fiber;

[0031] The perfluorosilane-modified high-strength alkali-free glass fiber is added to a pre-prepared polymer precursor solution, and then filtered, washed, dried, and heat-treated at 150-350° C. to obtain a polymer-coated high-strength alkali-free glass fiber;

[0032] The high-strength alkali-free glass fiber coated with a polymer is added to a pre-prepared nanomaterial dispersion, subjected to ultrasonic treatment for 30 to 60 minutes, filtered, washed, and dried after stirring to obtain a surface-modified high-strength alkali-free glass fiber;

[0033] The polytetrafluoroethylene resin, the surface-modified high-strength alkali-free glass fiber, the lubricating phase and the wetting dispersant are mixed in a mass ratio of 60-75:25-40:3-7:0.5-1.5, and premixed in a premixer with a rotation speed of 60-100 r / min for 5-30 minutes; the premixed material is transferred to a high-speed mixer, and mixed at a rotation speed of 2000-4000 r / min for 5-30 minutes to obtain a uniformly mixed mixed material; the mixed material is loaded into a mold, and pressed and formed at a pressure of 25-40 MPa to obtain a composite material blank; the composite material blank is placed in an oven, sintered and then cooled to room temperature to obtain a PTFE glass fiber.

[0034] The surface of glass fiber is usually covered with sizing agent. High temperature desizing treatment (350-450℃) causes thermal decomposition of the organic sizing agent on the surface of glass fiber, breaking and degrading the molecular chain, exposing the original surface of glass fiber. Then etching it with acid solution will cause the metal oxide on the surface of glass fiber to react with acid:

[0035] CaO+2HCl→CaCl2+H2O

[0036] Al2O3+6HCl→2AlCl3+3H2O

[0037] The surface Si-O-Si bonds are hydrolyzed to form a large number of Si-OH active groups:

[0038] ≡Si-O-Si≡+H2O→≡Si-OH+HO-Si≡

[0039] This step increases the surface roughness of the glass fiber, improves the specific surface area, generates a large number of hydroxyl active sites, prepares for the subsequent coupling reaction, and forms a microporous structure on the surface of the glass fiber.

[0040] The perfluorosilane modification treatment involves the following reactions.

[0041] Alkoxy groups hydrolyze to form silanol groups:

[0042] CF3(CF2)7(CH2)2Si(OCH2CH3)3+3H2O→CF3(CF2)7(CH2)2Si(OH)3+3CH3CH2OH

[0043] The silanol groups react with Si-OH on the glass fiber surface to form a condensation reaction:

[0044] CF3(CF2)7(CH2)2Si(OH)3+3(≡Si-OH)surface→(≡Si-O)3Si(CH2)2(CF2)7CF3+3H2O

[0045] Self-crosslinking between adjacent silanol groups forms a siloxane network:

[0046] 2[CF3(CF2)7(CH2)2Si(OH)3]→CF3(CF2)7(CH2)2Si(OH)2-O-Si(OH)2(CH2)2(CF2)7CF3+H2O

[0047] This step forms a covalently bonded fluorinated silicone layer on the glass fiber surface. The fluorinated groups (CF3(CF2)7) provide hydrophobicity and have structural similarities with the FCF segments of PTFE, thus acting as a bridge, with one end covalently linked to the glass fiber and the other end having affinity with PTFE.

[0048] In the polymer coating treatment, taking polyamic acid coating as an example, after adding the perfluorosilane-modified high-strength alkali-free glass fiber into the pre-prepared polyamic acid solution, the residual hydroxyl groups on the surface of the perfluorosilane-modified glass fiber form hydrogen bonds with the carboxyl groups in the polyamic acid, and then heat-treated at 150-350°C for thermal imidization reaction:

[0049] -CO-NH-C6H4-COOH→-CO-N(C6H4)-CO-+H2O

[0050] The amide group and the carboxyl group in the polyamic acid molecule undergo a cyclization reaction to form a rigid imidazole ring structure.

[0051] This step forms a flexible transition interface layer and increases the entanglement possibility with PTFE molecules.

[0052] Nanomaterial modification treatment increases the complexity and roughness of the interface microstructure, and nanoparticles fill the interface micropores to reduce the water molecule penetration channels.

[0053] The following detailed description is made to the embodiments of the present invention. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present invention. However, one or more embodiments may also be implemented by those skilled in the art without these specific details.

[0054] Example 1

[0055] The high-strength alkali-free glass fiber (mesh number 1250 mesh, average particle size 5-10 μm, aspect ratio 13:1) was placed in a muffle furnace at 400°C for 3 hours for high-temperature treatment to perform desizing treatment; the desizing high-strength alkali-free glass fiber was immersed in a dilute hydrochloric acid solution with a concentration of 0.1 mol / L, and reacted at 50°C for 2 hours for surface etching; the etched high-strength alkali-free glass fiber was repeatedly washed with deionized water until pH = 7.0, and then dried at 100°C for 8 hours to obtain activated high-strength alkali-free glass fiber;

[0056] 1H,1H,2H,2H-perfluorodecyltriethoxysilane is dissolved in ethanol to prepare a solution with a mass concentration of 3%, and the activated high-strength alkali-free glass fiber is added to the perfluorosilane solution, stirred and reacted at 70°C for 2 hours, filtered, washed with ethanol for 3 times, and then dried at 120°C for 4 hours to obtain perfluorosilane-modified high-strength alkali-free glass fiber;

[0057] The polyamic acid is dissolved in N,N-dimethylformamide to prepare a solution with a mass concentration of 10%, and the perfluorosilane-modified high-strength alkali-free glass fiber is added thereto, stirred for 2 hours, filtered, washed twice with N,N-dimethylformamide, dried, and then heat-treated under the following conditions: keeping warm at 100°C for 1 hour, keeping warm at 200°C for 1 hour, and keeping warm at 300°C for 1 hour to obtain a polyimide-coated modified high-strength alkali-free glass fiber;

[0058] Alumina nanoparticles (average particle size 50 nm) are dispersed in ethanol to form a stable dispersion with a mass concentration of 1%, and high-strength alkali-free glass fiber coated and modified by polyimide is added to the dispersion, ultrasonically treated for 45 minutes, stirred for 2 hours, filtered, washed with ethanol, and dried at 120° C. for 4 hours to obtain high-strength alkali-free glass fiber modified by alumina nanoparticles;

[0059] The polytetrafluoroethylene resin, high-strength alkali-free glass fiber modified with alumina nanoparticles, graphite and stearic acid are mixed in a mass ratio of 70:30:5:1, and premixed in a premixer with a rotation speed of 90 r / min for 20 minutes; the premixed material is transferred to a high-speed mixer, mixed at a rotation speed of 3500 r / min for 15 minutes to obtain a uniformly mixed composite material mixture; the mixed material is loaded into a mold, and pressed at a pressure of 30 MPa to obtain a composite material blank; the blank is placed in an oven and sintered according to the following procedures: heating from room temperature to 250°C at a rate of 4°C / min, and keeping warm for 30 minutes; then heating to 360°C at a rate of 1.5°C / min, and keeping warm for 90 minutes; then cooling to 250°C at a rate of 1.5°C / min, and then cooling to room temperature by natural cooling to obtain PTFE glass fiber.

[0060] Example 2

[0061] The high-strength alkali-free glass fiber (mesh number 1500, average particle size 3-8μm, aspect ratio 15:1) is placed in a muffle furnace at 420°C for high temperature treatment for 3.5 hours to perform desizing treatment; the desizing high-strength alkali-free glass fiber is immersed in a mixed acid solution of a 0.15mol / L dilute hydrochloric acid solution and a 0.15mol / L dilute sulfuric acid solution in a volume ratio of 1:1, and reacted at 55°C for 2.5 hours to perform surface etching; the etched high-strength alkali-free glass fiber is repeatedly washed with deionized water until pH = 7.0, and then dried at 110°C for 10 hours to obtain an activated high-strength alkali-free glass fiber;

[0062] 1H,1H,2H,2H-perfluorodecyltrichlorosilane is dissolved in tetrahydrofuran to prepare a solution with a mass concentration of 4%; activated high-strength alkali-free glass fiber is added to the perfluorosilane solution, and stirred for reaction at 75°C for 2.5 hours; filtered, washed with tetrahydrofuran for 3 times, and then dried at 130°C for 5 hours to obtain perfluorosilane-modified high-strength alkali-free glass fiber;

[0063] The polyetheretherketone is dissolved in dichloromethane to prepare a solution with a mass concentration of 8%, and the perfluorosilane-modified high-strength alkali-free glass fiber is added thereto, stirred for 3 hours, filtered, washed twice with dichloromethane, dried, and then heat-treated at 280°C for 2 hours to obtain the polyetheretherketone-coated modified high-strength alkali-free glass fiber;

[0064] The carbon nanotubes are dispersed in N,N-dimethylformamide to form a stable dispersion with a mass concentration of 0.5%, and the high-strength alkali-free glass fiber coated with polyetheretherketone is added to the dispersion, ultrasonically treated for 60 minutes, stirred for 3 hours, filtered, washed with N,N-dimethylformamide, and dried at 140°C for 6 hours to obtain the high-strength alkali-free glass fiber modified with carbon nanotubes;

[0065] The polytetrafluoroethylene resin, the high-strength alkali-free glass fiber modified with carbon nanotubes, tungsten disulfide and sodium dodecylbenzene sulfonate are mixed in a mass ratio of 60:40:7:1.5, and premixed in a premixer with a rotation speed of 100 r / min for 25 minutes; the premixed material is transferred to a high-speed mixer, mixed at a rotation speed of 4000 r / min for 20 minutes, and a uniformly mixed composite material mixture is obtained; the mixed material is loaded into a mold, and pressed at a pressure of 40 MPa to obtain a composite material blank; the blank is placed in an oven and sintered according to the following procedure: heating from room temperature to 250°C at a rate of 2.5°C / min, and keeping warm for 30 minutes; then heating to 370°C at a rate of 1°C / min, and keeping warm for 120 minutes; then cooling to 250°C at a rate of 1°C / min, and then cooling to room temperature by natural cooling to obtain PTFE glass fiber.

[0066] Comparative Example 1

[0067] The polytetrafluoroethylene resin and the high-strength alkali-free glass fiber without surface modification (mesh number 1250 mesh, average particle size 5-10 μm, aspect ratio 13:1) are mixed in a mass ratio of 75:25, and premixed in a premixer with a rotation speed of 80 r / min for 15 minutes; the premixed material is transferred to a high-speed mixer, and mixed at a rotation speed of 3000 r / min for 10 minutes to obtain a uniformly mixed composite material mixture; the mixed material is loaded into a mold, and pressed at a pressure of 35 MPa to obtain a composite material blank; the blank is placed in an oven, sintered at 360° C. for 60 minutes, and then naturally cooled to room temperature to obtain a PTFE glass fiber without surface modification.

[0068] Comparative Example 2

[0069] The high-strength alkali-free glass fiber (mesh number 1250 mesh, average particle size 5-10 μm, aspect ratio 13:1) was placed in a muffle furnace at 400°C for 3 hours for high-temperature treatment to perform desizing treatment; the desizing high-strength alkali-free glass fiber was immersed in a dilute hydrochloric acid solution with a concentration of 0.1 mol / L, and reacted at 50°C for 2 hours for surface etching; the etched high-strength alkali-free glass fiber was repeatedly washed with deionized water until pH = 7.0, and then dried at 100°C for 8 hours to obtain activated high-strength alkali-free glass fiber;

[0070] The polytetrafluoroethylene resin and the activated high-strength alkali-free glass fiber are mixed in a mass ratio of 75:25, and premixed in a premixer at a rotation speed of 80 r / min for 15 minutes; the premixed material is transferred to a high-speed mixer, and mixed at a rotation speed of 3000 r / min for 10 minutes to obtain a uniformly mixed composite material mixture; the mixed material is loaded into a mold, and pressed at a pressure of 35 MPa to obtain a composite material blank; the blank is placed in an oven, sintered at 360° C. for 60 minutes, and then naturally cooled to room temperature to obtain a PTFE glass fiber that has only been etched with an acid solution.

[0071] Comparative Example 3

[0072] The high-strength alkali-free glass fiber (mesh number 1250 mesh, average particle size 5-10 μm, aspect ratio 13:1) was placed in a muffle furnace at 400°C for 3 hours for high-temperature treatment to perform desizing treatment; the desizing high-strength alkali-free glass fiber was immersed in a dilute hydrochloric acid solution with a concentration of 0.1 mol / L, and reacted at 50°C for 2 hours for surface etching; the etched high-strength alkali-free glass fiber was repeatedly washed with deionized water until pH = 7.0, and then dried at 100°C for 8 hours to obtain activated high-strength alkali-free glass fiber;

[0073] 1H,1H,2H,2H-perfluorodecyltriethoxysilane is dissolved in ethanol to prepare a solution with a mass concentration of 3%; activated high-strength alkali-free glass fiber is added to the perfluorosilane solution, and stirred for reaction at 70°C for 2 hours; filtered, washed with ethanol for 3 times, and then dried at 120°C for 4 hours to obtain perfluorosilane-modified high-strength alkali-free glass fiber;

[0074] The polytetrafluoroethylene resin and the high-strength alkali-free glass fiber modified by perfluorosilane are mixed in a mass ratio of 75:25, and premixed in a premixer with a rotation speed of 80 r / min for 15 minutes; the premixed material is transferred to a high-speed mixer, and mixed at a rotation speed of 3000 r / min for 10 minutes to obtain a uniformly mixed composite material mixture; the mixed material is loaded into a mold, and pressed at a pressure of 35 MPa to obtain a composite material blank; the blank is placed in an oven, sintered at 365°C for 60 minutes, and then naturally cooled to room temperature to obtain a PTFE glass fiber treated only with perfluorosilane.

[0075] The performance of the PTFE glass fibers prepared in Examples 1-2 and Comparative Examples 1-3 was tested, and the results are shown in Table 1.

[0076] Table 1 Performance test results of various embodiments and comparative examples

[0077] Performance Indicators Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Tensile strength(MPa) 24.3 26.8 15.6 17.8 19.2 Elongation at break (%) 230 215 180 195 210 Shore Hardness (ShoreD) 74 78 65 68 71 <![CDATA[Specific gravity (g / cm 3 )]]> 2.32 2.38 2.20 2.22 2.24 Friction coefficient 0.07 0.06 0.14 0.12 0.10 Water absorption (%) 0.010 0.008 0.038 0.025 0.018

[0078] It can be seen that although the comparative example 1 uses high-strength alkali-free glass fiber without surface modification, it has certain water-proof performance, but due to poor interface bonding, the mechanical properties are relatively low. The comparative example 2 is only treated with acid solution etching, and the interface bonding is improved but still not ideal. The comparative example 3 is treated with perfluorosilane, and the interface bonding is significantly improved, but due to the lack of polymer coating treatment and nanomaterial modification treatment, the interface transition effect is insufficient, and the comprehensive performance is still lower than that of Examples 1-2. Figure 2 It can be seen that there are almost no holes on the surface of the PTFE glass fiber in Example 1, and the material is dense, which is due to the obvious improvement of the problems of easy water penetration and poor interface bonding by the preparation method.

[0079] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core ideas of the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing PTFE glass fiber, characterized in that: The method comprises the following steps: The high-strength alkali-free glass fiber is subjected to high-temperature treatment for desizing, and the desizing high-strength alkali-free glass fiber is immersed in an acid solution, reacted at 40 to 60° C. for 1 to 3 hours for surface etching, and the etched high-strength alkali-free glass fiber is washed with deionized water to neutrality, and dried to obtain a surface-activated high-strength alkali-free glass fiber; The perfluorosilane is dissolved in an organic solvent to prepare a solution with a mass concentration of 1% to 5%, the surface activated high-strength alkali-free glass fiber is added to the perfluorosilane solution, stirred and reacted at 60 to 80° C. for 1 to 3 hours, filtered, washed with a solvent, and dried to obtain the perfluorosilane-modified high-strength alkali-free glass fiber; The perfluorosilane-modified high-strength alkali-free glass fiber is added to a pre-prepared polymer precursor solution, and then filtered, washed, dried, and heat-treated at 150-350° C. to obtain a polymer-coated high-strength alkali-free glass fiber; The high-strength alkali-free glass fiber coated with a polymer is added to a pre-prepared nanomaterial dispersion, subjected to ultrasonic treatment for 30 to 60 minutes, filtered, washed, and dried after stirring to obtain a surface-modified high-strength alkali-free glass fiber; The polytetrafluoroethylene resin, the surface-modified high-strength alkali-free glass fiber, the lubricating phase and the wetting dispersant are mixed in a mass ratio of 60-75:25-40:3-7:0.5-1.5, the mixed material is put into a mold, and the mold is pressed at a pressure of 25-40 MPa to obtain a composite material blank, and the composite material blank is put into an oven, sintered and then cooled to room temperature to obtain PTFE glass fiber.

2. The method for preparing a PTFE glass fiber according to claim 1, wherein: The high-strength alkali-free glass fiber has a mesh number of 800 to 1500 meshes, an average particle size of 3 to 15 μm, and an aspect ratio of 10 to 20:

1.

3. The method for preparing a PTFE glass fiber according to claim 1, wherein: The acidic solution is a dilute sulfuric acid solution, a dilute hydrochloric acid solution or a mixed solution of the two with a mass concentration of 0.05 to 0.5 mol / L.

4. The method for preparing a PTFE glass fiber according to claim 1, wherein: The polymer precursor solution is a solution prepared by dissolving polyamic acid in N,N-dimethylformamide with a mass concentration of 10%, or a solution prepared by dissolving polyetheretherketone in dichloromethane with a mass concentration of 8%.

5. The method for preparing PTFE glass fiber according to claim 1, characterized in that: The nano material dispersion is a dispersion with a mass concentration of 1% prepared by dispersing aluminum oxide nanoparticles with an average particle size of 50 nm in ethanol, or a dispersion with a mass concentration of 0.5% prepared by dispersing carbon nanotubes in N,N-dimethylformamide.

6. The method for preparing PTFE glass fiber according to claim 1, characterized in that: The lubricating phase is selected from one or more of molybdenum disulfide, graphite, and tungsten disulfide.

7. The method for preparing a PTFE glass fiber according to claim 1, characterized in that: The wetting and dispersing agent is selected from one or more of stearic acid, sodium dodecyl sulfate and sodium dodecylbenzene sulfonate.

8. The method for preparing PTFE glass fiber according to claim 1, characterized in that: The sintering steps specifically include: heating from room temperature to 250°C at a rate of 2-5°C / min, and keeping the temperature for 30 minutes; then heating to 350-380°C at a rate of 1-3°C / min, and keeping the temperature for 30-120 minutes; then cooling to 250°C at a rate of 1-3°C / min, and then cooling to room temperature by natural cooling.

9. A PTFE glass fiber prepared by the method for preparing a PTFE glass fiber as claimed in any one of claims 1 to 8.

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