Modified polytetrafluoroethylene pipe and preparation method thereof

Abstract

The invention relates to the technical field of pipes, in particular to a modified polytetrafluoroethylene pipe and a preparation method thereof. The modified polytetrafluoroethylene pipe is prepared from modified carbon nanotubes, hydroxylated polytetrafluoroethylene powder and polytetrafluoroethylene powder through extrusion forming and sintering, the modified carbon nanotubes are obtained by modifying carbon nanotubes with gamma-(2, 3-epoxypropoxy) propyltrimethoxysilane and perfluorooctyltriethoxysilane, and the modified polytetrafluoroethylene pipe is prepared from the modified carbon nanotubes and the perfluorooctyltriethoxysilane. The modified polytetrafluoroethylene pipe provided by the invention has excellent mechanical properties, especially notch impact strength, so that the modified polytetrafluoroethylene pipe can be widely applied to dynamic load and high impact environments.

Description

Technical Field

[0001] The invention relates to the technical field of pipes, and in particular to a modified polytetrafluoroethylene pipe and a preparation method thereof. Background Art

[0002] Polytetrafluoroethylene (PTFE) is a high-performance polymer made from tetrafluoroethylene, known for its excellent chemical inertness, high temperature resistance and low friction coefficient. PTFE remains stable over a wide temperature range and is resistant to corrosion by most chemicals, so it is widely used in chemical, electronic, mechanical and aerospace fields. However, the inherent mechanical properties of PTFE are insufficient, especially its low impact strength and elongation at break, which limits its use in certain high-stress applications.

[0003] Traditional PTFE tubing is prone to breakage or damage when subjected to external forces or impacts, which can lead to serious consequences in certain critical applications. Although PTFE has many excellent properties, its insufficient mechanical properties limit its application in dynamic load and high impact environments.

[0004] In recent years, with the development of nanotechnology, nanomaterials such as carbon nanotubes have been introduced into PTFE in order to improve its mechanical properties. Carbon nanotubes have excellent mechanical properties and electrical conductivity, and can significantly improve the strength and toughness of composite materials. However, due to the non-polar properties of PTFE, the dispersion and compatibility of carbon nanotubes in the PTFE matrix are poor, which limits its reinforcement effect. Summary of the invention

[0005] In view of this, the object of the present invention is to provide a modified polytetrafluoroethylene pipe to solve the problem that the polytetrafluoroethylene pipe is difficult to be used in dynamic load and high impact environments.

[0006] Based on the above purpose, the present invention provides a modified polytetrafluoroethylene tube, which is obtained by extrusion molding and sintering the following raw materials, by weight: 1-3 parts of modified carbon nanotubes, 5-20 parts of hydroxylated polytetrafluoroethylene powder and 80-120 parts of polytetrafluoroethylene powder.

[0007] Furthermore, the modified carbon nanotubes are obtained by modifying carbon nanotubes with γ-(2,3-epoxypropyloxy)propyltrimethoxysilane and tridecafluorooctyltriethoxysilane.

[0008] Furthermore, the weight ratio of the γ-(2,3-epoxypropyloxy)propyltrimethoxysilane, tridecafluorooctyltriethoxysilane and carbon nanotubes is 0.1-0.3:0.2-1:10-30.

[0009] Furthermore, the preparation method of the hydroxylated polytetrafluoroethylene is as follows: (1) Add polytetrafluoroethylene powder to tetrahydrofuran, ultrasonicate for 10-30 minutes, add sodium naphthalene treatment solution under nitrogen protection, stir for 5-20 minutes, then add deionized water to terminate the activation reaction, purify, and obtain activated polytetrafluoroethylene powder; (2) Add activated polytetrafluoroethylene powder into deionized water, ultrasonicate for 10-30 minutes, add ammonium persulfate under nitrogen protection, raise the temperature to 45-55°C, add hydroxyethyl methacrylate, continue stirring for 10-20 hours, and purify to obtain hydroxylated polytetrafluoroethylene powder.

[0010] Preferably, in step (1), the weight ratio of polytetrafluoroethylene powder, tetrahydrofuran, sodium naphthalene treatment solution and deionized water is 8-12:40-60:2-4:1-2.

[0011] Preferably, the amount of deionized water added in step (1) is 0.5-1 times the weight of the sodium naphthalene treatment solution.

[0012] Preferably, in step (2), the weight ratio of activated polytetrafluoroethylene powder, deionized water and hydroxyethyl methacrylate is 8-12:20-40:1-3.

[0013] Preferably, the amount of ammonium persulfate added in step (2) is 0.05%-0.2% by weight of hydroxyethyl methacrylate.

[0014] Preferably, the average particle size of the polytetrafluoroethylene powder is 100-300 μm.

[0015] Preferably, the carbon nanotubes have an outer diameter of 10-20 nm and a length of 0.5-2 μm.

[0016] Preferably, the preparation method of the modified carbon nanotubes is as follows: disperse carbon nanotubes in a mixed solution of ethanol and deionized water, add γ-(2,3-epoxypropoxy)propyltrimethoxysilane and tridecafluorooctyltriethoxysilane, heat to 55-65°C, stir the reaction for 65-7h, purify, and obtain modified carbon nanotubes.

[0017] Preferably, the weight ratio of the ethanol to deionized water is 3:2.

[0018] Furthermore, the present invention also provides a method for preparing a modified polytetrafluoroethylene tube, comprising the following steps: melt-mixing modified carbon nanotubes, hydroxylated polytetrafluoroethylene powder and polytetrafluoroethylene powder at 400-450°C, extruding and granulating to obtain a modified polytetrafluoroethylene masterbatch, then placing the modified polytetrafluoroethylene masterbatch into a mold for preforming to form a cylindrical billet, then placing the cylindrical billet into an extruder, extruding to form a tubular material, and finally sintering the tubular material at 350-370°C for 2.5-3.5h, cooling, and obtaining a modified polytetrafluoroethylene tube.

[0019] Beneficial effects of the present invention: The present invention significantly improves the mechanical properties of the material by modifying polytetrafluoroethylene, especially in terms of elongation at break and impact strength. First, although the tensile strength of the modified polytetrafluoroethylene pipe is slightly reduced, this change is not significant and can still meet the basic requirements of most applications. More importantly, the modified material has achieved a significant improvement in elongation at break and impact strength, especially the notched impact strength has been increased by more than three times. This enhanced notched impact strength means that the material is less likely to break or be damaged when subjected to external force or impact, thereby significantly improving the durability and service life of the pipe.

[0020] The present invention enhances the compatibility and dispersibility of polytetrafluoroethylene powder with carbon nanotubes by modifying the surface of polytetrafluoroethylene powder with hydroxyl groups. This modification enables the hydroxyl groups to form chemical bonds with the epoxy groups on the surface of the carbon nanotubes, thereby improving the elongation at break and the impact strength of the material. In addition, the introduction of epoxy groups and fluorine chains on the surface of the carbon nanotubes effectively regulates the mechanical properties of the polytetrafluoroethylene tube. While maintaining the tensile strength, the elongation at break is greatly improved, and the impact performance, especially the notched impact performance, is synergistically improved. The improvement of this performance is mainly attributed to the chemical crosslinking between the epoxy groups and the surface of the polytetrafluoroethylene and the physical entanglement between the fluorine chains and the polytetrafluoroethylene molecular chains.

[0021] In summary, the present invention significantly improves the mechanical properties of polytetrafluoroethylene pipes through chemical and physical dual modification methods, making them more reliable and durable in a wider range of applications. This modification strategy not only improves the performance of the material, but also provides new possibilities for the use of polytetrafluoroethylene in high-demand applications. DETAILED DESCRIPTION

[0022] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0023] In the specific embodiment of the present invention, polytetrafluoroethylene powder was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. with a product number of P434336 and an average particle size of 200 μm. The sodium naphthalene treatment solution was purchased from Dongguan Yihe Chemical Co., Ltd. with a model of YH-891. The carbon nanotubes were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. with a product number of C369044, with an outer diameter of 10-20 nm and a length of 0.5-2 μm. Embodiment 1:

[0024] (1) Add 80 g of polytetrafluoroethylene powder to 400 g of tetrahydrofuran, ultrasonicate for 10 min, add 20 g of sodium naphthalene treatment solution under nitrogen protection, stir for 5 min, then add 10 g of deionized water to terminate the activation reaction, then wash with acetone and filter under reduced pressure for 3 times, and vacuum dry to obtain activated polytetrafluoroethylene powder; (2) Add 80 g of activated polytetrafluoroethylene powder to 200 g of deionized water, ultrasonicate for 10 min, add 0.01 g of ammonium persulfate under nitrogen protection, heat to 45 °C, add 10 g of hydroxyethyl methacrylate, continue stirring for 10 h, then wash with deionized water and filter under reduced pressure for 3 times, and vacuum dry to obtain hydroxylated polytetrafluoroethylene powder; (3) Disperse 10 g of carbon nanotubes in a mixed solution of 120 g of ethanol and 80 g of deionized water, add 0.1 g of γ-(2,3-epoxypropoxy)propyltrimethoxysilane and 0.2 g of tridecafluorooctyltriethoxysilane, raise the temperature to 55 °C, stir and react for 5 h, wash with water, and dry to obtain modified carbon nanotubes; (4) 10 g of modified carbon nanotubes, 50 g of hydroxylated polytetrafluoroethylene powder and 800 g of polytetrafluoroethylene powder were melt-mixed at 400 °C and extruded to obtain modified polytetrafluoroethylene masterbatch. The modified polytetrafluoroethylene masterbatch was then loaded into a mold for preforming to form a cylindrical billet. The cylindrical billet was then put into an extruder and extruded to form a tubular material. Finally, the tubular material was sintered at 350 °C for 2.5 h and cooled to obtain a modified polytetrafluoroethylene tube. Embodiment 2:

[0025] (1) Add 100 g of polytetrafluoroethylene powder to 500 g of tetrahydrofuran, ultrasonicate for 20 min, add 30 g of sodium naphthalene treatment solution under nitrogen protection, stir for 10 min, then add 15 g of deionized water to terminate the activation reaction, then wash with acetone and filter under reduced pressure for 3 times, and vacuum dry to obtain activated polytetrafluoroethylene powder; (2) Add 100 g of activated polytetrafluoroethylene powder to 300 g of deionized water, ultrasonicate for 20 min, add 0.02 g of ammonium persulfate under nitrogen protection, heat to 50 °C, add 20 g of hydroxyethyl methacrylate, continue stirring for 15 h, then wash with deionized water and filter under reduced pressure for 3 times, and vacuum dry to obtain hydroxylated polytetrafluoroethylene powder; (3) Disperse 20 g of carbon nanotubes in a mixed solution of 120 g of ethanol and 80 g of deionized water, add 0.2 g of γ-(2,3-epoxypropoxy)propyltrimethoxysilane and 0.5 g of tridecafluorooctyltriethoxysilane, raise the temperature to 60 °C, stir and react for 6 h, wash with water, and dry to obtain modified carbon nanotubes; (4) 20 g of modified carbon nanotubes, 100 g of hydroxylated polytetrafluoroethylene powder and 1000 g of polytetrafluoroethylene powder are melt-mixed at 420°C and extruded into granules to obtain modified polytetrafluoroethylene masterbatch. The modified polytetrafluoroethylene masterbatch is then loaded into a mold for preforming to form a cylindrical billet. The cylindrical billet is then put into an extruder and extruded to form a tubular material. Finally, the tubular material is sintered at 360°C for 3 h and cooled to obtain a modified polytetrafluoroethylene tube. Embodiment 3:

[0026] (1) Add 120 g of polytetrafluoroethylene powder to 600 g of tetrahydrofuran, ultrasonicate for 30 min, add 40 g of sodium naphthalene treatment solution under nitrogen protection, stir for 20 min, then add 40 g of deionized water to terminate the activation reaction, then wash with acetone and filter under reduced pressure for 3 times, and vacuum dry to obtain activated polytetrafluoroethylene powder; (2) Add 120 g of activated polytetrafluoroethylene powder to 400 g of deionized water, ultrasonicate for 30 min, add 0.06 g of ammonium persulfate under nitrogen protection, heat to 55 °C, add 30 g of hydroxyethyl methacrylate, continue stirring for 20 h, then wash with deionized water and filter under reduced pressure for 3 times, and vacuum dry to obtain hydroxylated polytetrafluoroethylene powder; (3) Disperse 30 g of carbon nanotubes in a mixed solution of 120 g of ethanol and 80 g of deionized water, add 0.3 g of γ-(2,3-epoxypropoxy)propyltrimethoxysilane and 1 g of tridecafluorooctyltriethoxysilane, raise the temperature to 65 °C, stir and react for 7 h, wash with water, and dry to obtain modified carbon nanotubes; (4) 30 g of modified carbon nanotubes, 200 g of hydroxylated polytetrafluoroethylene powder and 1200 g of polytetrafluoroethylene powder were melt-mixed at 450°C and extruded into granules to obtain modified polytetrafluoroethylene masterbatch. The modified polytetrafluoroethylene masterbatch was then loaded into a mold for preforming to form a cylindrical billet. The cylindrical billet was then put into an extruder and extruded to form a tubular material. Finally, the tubular material was sintered at 370°C for 3.5 h and cooled to obtain a modified polytetrafluoroethylene tube.

[0027] Comparative Example 1: The difference between Comparative Example 1 and Example 2 is that the polytetrafluoroethylene powder is not hydroxyl-modified; The specific steps are as follows: (1) Disperse 20 g of carbon nanotubes in a mixed solution of 120 g of ethanol and 80 g of deionized water, add 0.2 g of γ-(2,3-epoxypropoxy)propyltrimethoxysilane and 0.5 g of tridecafluorooctyltriethoxysilane, heat to 60 °C, stir and react for 6 h, wash with water, and dry to obtain modified carbon nanotubes; (2) 20 g of modified carbon nanotubes and 1100 g of polytetrafluoroethylene powder are melt-mixed at 420°C and extruded into granules to obtain modified polytetrafluoroethylene masterbatch. The modified polytetrafluoroethylene masterbatch is then loaded into a mold for preforming to form a cylindrical billet. The cylindrical billet is then put into an extruder and extruded to form a tubular material. Finally, the tubular material is sintered at 360°C for 3 hours and cooled to obtain a polytetrafluoroethylene tube.

[0028] Comparative Example 2: The difference between Comparative Example 2 and Example 2 is that only γ-(2,3-epoxypropyloxy)propyltrimethoxysilane is grafted onto the surface of the carbon nanotubes; The specific steps are as follows: (1) Add 100 g of polytetrafluoroethylene powder to 500 g of tetrahydrofuran, ultrasonicate for 20 min, add 30 g of sodium naphthalene treatment solution under nitrogen protection, stir for 10 min, then add 15 g of deionized water to terminate the activation reaction, then wash with acetone and filter under reduced pressure for 3 times, and vacuum dry to obtain activated polytetrafluoroethylene powder; (2) Add 100 g of activated polytetrafluoroethylene powder to 300 g of deionized water, ultrasonicate for 20 min, add 0.02 g of ammonium persulfate under nitrogen protection, heat to 50 °C, add 20 g of hydroxyethyl methacrylate, continue stirring for 15 h, then wash with deionized water and filter under reduced pressure for 3 times, and vacuum dry to obtain hydroxylated polytetrafluoroethylene powder; (3) Disperse 20 g of carbon nanotubes in a mixed solution of 120 g of ethanol and 80 g of deionized water, add 0.7 g of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, heat to 60 °C, stir and react for 6 h, wash with water, and dry to obtain modified carbon nanotubes; (4) 20 g of modified carbon nanotubes, 100 g of hydroxylated polytetrafluoroethylene powder and 1000 g of polytetrafluoroethylene powder are melt-mixed at 420°C and extruded into granules to obtain modified polytetrafluoroethylene masterbatch. The modified polytetrafluoroethylene masterbatch is then loaded into a mold for preforming to form a cylindrical billet. The cylindrical billet is then put into an extruder and extruded to form a tubular material. Finally, the tubular material is sintered at 360°C for 3 h and cooled to obtain a polytetrafluoroethylene tube.

[0029] Comparative Example 3: The difference between Comparative Example 3 and Example 2 is that only tridecafluorooctyltriethoxysilane is grafted onto the surface of the carbon nanotubes; The specific steps are as follows: (1) Add 100 g of polytetrafluoroethylene powder to 500 g of tetrahydrofuran, ultrasonicate for 20 min, add 30 g of sodium naphthalene treatment solution under nitrogen protection, stir for 10 min, then add 15 g of deionized water to terminate the activation reaction, then wash with acetone and filter under reduced pressure for 3 times, and vacuum dry to obtain activated polytetrafluoroethylene powder; (2) Add 100 g of activated polytetrafluoroethylene powder to 300 g of deionized water, ultrasonicate for 20 min, add 0.02 g of ammonium persulfate under nitrogen protection, heat to 50 °C, add 20 g of hydroxyethyl methacrylate, continue stirring for 15 h, then wash with deionized water and filter under reduced pressure for 3 times, and vacuum dry to obtain hydroxylated polytetrafluoroethylene powder; (3) Dispersing 20 g of carbon nanotubes in a mixed solution of 120 g of ethanol and 80 g of deionized water, adding 0.7 g of tridecafluorooctyl triethoxysilane, heating to 60 ° C, stirring for 6 h, washing with water, and drying to obtain modified carbon nanotubes; (4) 20 g of modified carbon nanotubes, 100 g of hydroxylated polytetrafluoroethylene powder and 1000 g of polytetrafluoroethylene powder are melt-mixed at 420°C and extruded into granules to obtain modified polytetrafluoroethylene masterbatch. The modified polytetrafluoroethylene masterbatch is then loaded into a mold for preforming to form a cylindrical billet. The cylindrical billet is then put into an extruder and extruded to form a tubular material. Finally, the tubular material is sintered at 360°C for 3 h and cooled to obtain a polytetrafluoroethylene tube.

[0030] Comparative Example 4: The difference between Comparative Example 4 and Example 2 is that the carbon nanotubes are not modified; The specific steps are as follows: (1) Add 100 g of polytetrafluoroethylene powder to 500 g of tetrahydrofuran, ultrasonicate for 20 min, add 30 g of sodium naphthalene treatment solution under nitrogen protection, stir for 10 min, then add 15 g of deionized water to terminate the activation reaction, then wash with acetone and filter under reduced pressure for 3 times, and vacuum dry to obtain activated polytetrafluoroethylene powder; (2) Add 100 g of activated polytetrafluoroethylene powder to 300 g of deionized water, ultrasonicate for 20 min, add 0.02 g of ammonium persulfate under nitrogen protection, heat to 50 °C, add 20 g of hydroxyethyl methacrylate, continue stirring for 15 h, then wash with deionized water and filter under reduced pressure for 3 times, and vacuum dry to obtain hydroxylated polytetrafluoroethylene powder; (3) 20 g of carbon nanotubes, 100 g of hydroxylated polytetrafluoroethylene powder and 1000 g of polytetrafluoroethylene powder are melt-mixed at 420°C and extruded into granules to obtain a modified polytetrafluoroethylene masterbatch. The modified polytetrafluoroethylene masterbatch is then loaded into a mold for preforming to form a cylindrical billet. The cylindrical billet is then put into an extruder and extruded to form a tubular material. Finally, the tubular material is sintered at 360°C for 3 hours and cooled to obtain a polytetrafluoroethylene tube.

[0031] Comparative Example 5: Comparative Example 5 is a polytetrafluoroethylene pipe; The specific steps are as follows: The polytetrafluoroethylene powder is melt-mixed at 420°C, extruded and granulated to obtain a modified polytetrafluoroethylene masterbatch, and then the modified polytetrafluoroethylene masterbatch is loaded into a mold for preforming to form a cylindrical billet, and then the cylindrical billet is put into an extruder and extruded to form a tubular material, and finally the tubular material is sintered at 360°C for 3 hours and cooled to obtain a polytetrafluoroethylene pipe.

[0032] Performance Test: Tensile performance test: carried out on a universal testing machine in accordance with GB / T 1040-1992.

[0033] Impact strength test: Tested on an impact testing machine according to ISO 180:2000.

[0034] Table 1 Performance test results

[0035] Data Analysis: From the data of Examples 1-3 and Comparative Example 5 in Table 1, it can be seen that, compared with the traditional polytetrafluoroethylene pipe, the modified polytetrafluoroethylene pipe prepared by the present invention has a slight decrease in tensile strength, but the difference is not significant, and the elongation at break and impact strength are greatly improved. Most importantly, the notched impact strength is improved by more than 3 times. The enhanced notched impact strength means that the material is less likely to break or be damaged when subjected to external force or impact, thereby improving the durability and service life of the pipe.

[0036] It can be seen from the data of Example 2 and Comparative Example 1 in Table 1 that the hydroxyl modification on the surface of the polytetrafluoroethylene powder helps to improve the elongation at break and the impact strength. This is because the hydroxyl groups on the surface of the polytetrafluoroethylene powder can form chemical bonds with the epoxy groups on the surface of the carbon nanotubes, thereby improving the compatibility and dispersibility of the carbon nanotubes in the polytetrafluoroethylene.

[0037] It can be seen from the data of Example 2 and Comparative Examples 2-4 in Table 1 that the epoxy groups and fluorine chains on the surface of the carbon nanotubes effectively regulate the mechanical properties of the polytetrafluoroethylene tube, greatly improve the elongation at break while maintaining the tensile strength, and synergistically improve the impact performance, especially the notched impact performance, which is due to the chemical crosslinking of the epoxy groups and the polytetrafluoroethylene surface and the physical entanglement between the fluorine chains and the polytetrafluoroethylene molecular chains.

[0038] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

Claims

1. A modified polytetrafluoroethylene pipe, characterized in that: The following raw materials are extruded and sintered to obtain the modified carbon nanotubes by weight: 1-3 parts, hydroxylated polytetrafluoroethylene powder by weight 5-20 parts and polytetrafluoroethylene powder by weight 80-120 parts; The modified carbon nanotubes are obtained by modifying carbon nanotubes with γ-(2,3-epoxypropyloxy)propyltrimethoxysilane and tridecafluorooctyltriethoxysilane; The weight ratio of the γ-(2,3-epoxypropoxy)propyltrimethoxysilane, tridecafluorooctyltriethoxysilane and carbon nanotubes is 0.1-0.3:0.2-1:10-30; The preparation method of the hydroxylated polytetrafluoroethylene is as follows: (1) Add polytetrafluoroethylene powder to tetrahydrofuran, ultrasonicate for 10-30 minutes, add sodium naphthalene treatment solution under nitrogen protection, stir for 5-20 minutes, then add deionized water to terminate the activation reaction, purify, and obtain activated polytetrafluoroethylene powder; (2) Add activated polytetrafluoroethylene powder to deionized water, ultrasonicate for 10-30 minutes, add ammonium persulfate under nitrogen protection, heat to 45-55°C, add hydroxyethyl methacrylate, continue stirring for 10-20 hours, and purify to obtain hydroxylated polytetrafluoroethylene powder; In the step (1), the weight ratio of polytetrafluoroethylene powder, tetrahydrofuran, sodium naphthalene treatment solution and deionized water is 8-12:40-60:2-4:1-2; In the step (2), the weight ratio of activated polytetrafluoroethylene powder, deionized water and hydroxyethyl methacrylate is 8-12:20-40:1-3.

2. The modified polytetrafluoroethylene pipe according to claim 1, characterized in that: The average particle size of the polytetrafluoroethylene powder is 100-300 μm.

3. The modified polytetrafluoroethylene pipe according to claim 1, characterized in that: The outer diameter of the carbon nanotube is 10-20 nm, and the length is 0.5-2 μm.

4. The modified polytetrafluoroethylene pipe according to claim 1, characterized in that: The preparation method of the modified carbon nanotubes is as follows: dispersing carbon nanotubes in a mixed solution of ethanol and deionized water, adding γ-(2,3-epoxypropoxy)propyltrimethoxysilane and tridecafluorooctyltriethoxysilane, heating to 55-65° C., stirring and reacting for 65-7 hours, and purifying to obtain modified carbon nanotubes.

5. The modified polytetrafluoroethylene pipe according to claim 4, characterized in that: The weight ratio of the ethanol to deionized water is 3:

2.

6. The modified polytetrafluoroethylene pipe according to claim 1, characterized in that: The amount of deionized water added in step (1) is 0.5-1 times the weight of the sodium naphthalene treatment solution.

7. The modified polytetrafluoroethylene pipe according to claim 1, characterized in that: The amount of ammonium persulfate added in step (2) is 0.05%-0.2% of the weight of hydroxyethyl methacrylate.

8. A method for preparing a modified polytetrafluoroethylene pipe according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: melting and mixing modified carbon nanotubes, hydroxylated polytetrafluoroethylene powder and polytetrafluoroethylene powder at 400-450°C, extruding and granulating to obtain modified polytetrafluoroethylene masterbatch, then loading the modified polytetrafluoroethylene masterbatch into a mold for preforming to form a cylindrical blank, then putting the cylindrical blank into an extruder and extruding to form a tubular material, and finally sintering the tubular material at 350-370°C for 2.5-3.5h and cooling to obtain a modified polytetrafluoroethylene tube.

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