Preparation of polyaniline-doped graphene oxide-modified PTFE conductive composite materials

Abstract

This invention belongs to the field of polytetrafluoroethylene (PTFE) materials and provides a method for preparing a polyaniline-doped graphene oxide-modified PTFE conductive composite material. The material is composed of the following raw materials in weight percentages: 3-5 parts glass fiber, 0.5-1.5 parts phytic acid-sulfuric acid-polyaniline-doped graphene oxide, 4-8 parts copper powder, and 100 parts polytetrafluoroethylene (PTFE). Through filler modification, the original excellent properties of PTFE are further enhanced, including its creep resistance, wear resistance, and conductivity. It can be widely used in chemical engineering, electronics, automotive and home appliances, precision instruments, aerospace, and food industries.

Description

Technical Field

[0001] This invention belongs to the field of polytetrafluoroethylene materials, and specifically relates to the preparation of polyaniline-doped graphene oxide-modified PTFE conductive composite materials. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Polytetrafluoroethylene (PTFE) granules are molding grade suspension materials with a granulation diameter between 0.2mm and 1.0mm. They are granulated from powder and can be filled with glass fiber, carbon fiber, graphite, copper powder, stainless steel, etc. They are suitable for producing molded tubes, special-shaped parts, gaskets, plug seals, PTFE insulators, PTFE ball valves, PTFE valves, various PTFE seals, automatic machine molded parts, and other products.

[0004] Polytetrafluoroethylene (PTFE) is an insulating material with high resistivity, which makes it prone to static electricity buildup on its surface. When exposed to chemical dust or coal dust environments, there is a potential explosion hazard. Therefore, improving the conductivity of PTFE granules to give them antistatic properties is particularly important.

[0005] Currently, conductivity is generally improved by adding conductive materials such as carbon fibers, graphene oxide, carbon nanotubes, and graphite. Polyaniline-doped graphene oxide exhibits high conductivity, but the inventors have discovered that it is difficult to effectively disperse polyaniline-doped graphene oxide in polytetrafluoroethylene (PTFE) granules to form stable conductive pathways. Therefore, there are currently no reports on polyaniline-doped graphene oxide-modified PTFE conductive composite materials. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a polyaniline-doped graphene oxide-modified PTFE conductive composite material and its preparation method. This invention modifies polytetrafluoroethylene (PTFE) granules using phytic acid-sulfuric acid-doped graphene oxide, effectively improving its conductivity and mechanical properties. Polyaniline's three-dimensional structure contains numerous electron-rich sites, resulting in high electrochemical activity. Doping graphene oxide with polyaniline nanofibers effectively enhances the electrochemical activity of polyaniline due to graphene oxide's extremely high specific surface area and strong electron conductivity. Furthermore, this invention improves the solubility and conductivity of polyaniline through co-doping with phytic acid and sulfuric acid, allowing the polyaniline-doped graphene oxide to be well dispersed in the PTFE granules, significantly improving the composite material's conductivity and mechanical properties.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a polyaniline-doped graphene oxide-modified PTFE conductive composite material, which is composed of the following raw materials in parts by weight: 3-5 parts glass fiber, 0.5-1.5 parts phytic acid sulfuric acid-polyaniline-doped graphene oxide, 4-8 parts copper powder, and 100 parts polytetrafluoroethylene.

[0009] The preparation method of phytic acid-sulfuric acid-polyaniline-doped graphene oxide includes:

[0010] Co-doping of polyaniline with phytic acid and sulfuric acid yielded co-doped polyaniline nanofiber materials.

[0011] The co-doped polyaniline nanofiber material was used to dope graphene oxide to obtain phytic acid-sulfuric acid-polyaniline-doped graphene oxide.

[0012] In some embodiments, the bulk density of the polyaniline-doped graphene oxide-modified PTFE conductive composite material is ≥700±100.

[0013] A second aspect of the present invention provides a method for preparing a polyaniline-doped graphene oxide-modified PTFE conductive composite material, comprising:

[0014] Co-doping of polyaniline with phytic acid and sulfuric acid yielded co-doped polyaniline nanofiber materials.

[0015] The co-doped polyaniline nanofiber material was used to dope graphene oxide to obtain phytic acid-sulfuric acid-polyaniline-doped graphene oxide.

[0016] The phytic acid-sulfuric acid-polyaniline-doped graphene oxide, polytetrafluoroethylene powder, glass fiber, and copper powder are mixed evenly, molded, and sintered to obtain a polyaniline-doped graphene oxide-modified PTFE conductive composite material.

[0017] In some embodiments, the co-doping employs a "doping-dedoping-redoping" method, specifically including the following steps:

[0018] Aniline was added to a sulfuric acid solution and mixed thoroughly. Then ammonium persulfate was added and the mixture was allowed to react at 4-5°C to obtain sulfuric acid-doped polyaniline nanofibers.

[0019] The sulfuric acid-doped polyaniline nanofibers were immersed in an ammonia solution with a mass concentration of 3%-4% for dedoping for 12-16 hours to obtain basic polyaniline nanofibers.

[0020] The basic polyaniline nanofibers were immersed in a 0.05-0.08 mol / L phytic acid aqueous solution and ultrasonically treated for 3-4 hours to obtain co-doped polyaniline nanofiber materials.

[0021] The co-doped polyaniline nanofiber material was added to a graphene oxide dispersion with a concentration of 1-5 mg / mL, thoroughly impregnated, and freeze-dried to obtain a layered phytic acid-sulfuric acid-polyaniline-doped graphene oxide.

[0022] In some embodiments, the mass ratio of ammonium persulfate to aniline is 2.8-3:4.8-5.

[0023] In some embodiments, the concentration of the graphene oxide solution is 0.5-1.5 mg / mL.

[0024] In some embodiments, the molding conditions are 60-66 MPa for 5-10 minutes.

[0025] In some embodiments, the sintering conditions are sintering at 320℃-370℃ for 2-4 hours.

[0026] In some embodiments, graphene oxide is prepared using a modified Hummer process.

[0027] This invention also provides the application of phytic acid-sulfuric acid-polyaniline-doped graphene oxide in improving the properties of polytetrafluoroethylene.

[0028] Beneficial effects of the present invention

[0029] (1) In this invention, polyaniline has a large number of electron-rich sites in its three-dimensional spatial structure and has high electrochemical activity. By doping graphene oxide with polyaniline nanofibers, the ultra-high specific surface area and strong electronic conductivity of graphene oxide can effectively improve the electrochemical activity of polyaniline. At the same time, this invention also improves the solubility and conductivity of polyaniline by co-doping polyaniline with phytic acid and sulfuric acid, so that the polyaniline-doped graphene oxide can be well dispersed in polytetrafluoroethylene (PTFE) granules, which significantly improves the conductivity and mechanical properties of the composite material.

[0030] (2) This invention uses filler modification to enhance the original excellent properties of PTFE, thereby improving its creep resistance, wear resistance, and electrical conductivity. It can be widely used in chemical engineering, electronics, automotive and home appliances, precision instruments, aerospace, food and other fields.

[0031] (3) The preparation method of the present invention is simple, practical and easy to promote. Detailed Implementation

[0032] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0033] The present invention will be further described in detail below with reference to specific embodiments. It should be noted that the specific embodiments are explanations of the present invention and not limitations thereof.

[0034] Example 1

[0035] Formula: 4 parts glass fiber, 1 part phytic acid sulfuric acid-polyaniline doped graphene oxide, 6 parts copper powder, 100 parts polytetrafluoroethylene;

[0036] Preparation methods include:

[0037] (1) Add 4.8g of aniline to a 1mol / L sulfuric acid solution, mix well, and then add 2.8g of ammonium persulfate to react at 4℃ to obtain sulfuric acid-doped polyaniline nanofibers;

[0038] (2) The sulfuric acid-doped polyaniline nanofibers were immersed in an ammonia solution with a mass concentration of 3% for 12 hours to remove the doping, thereby obtaining basic polyaniline nanofibers.

[0039] (3) The basic polyaniline nanofibers were immersed in a 0.05 mol / L phytic acid aqueous solution and ultrasonically treated for 3 h to obtain co-doped polyaniline nanofiber material.

[0040] (4) The co-doped polyaniline nanofiber material was added to a graphene oxide dispersion with a concentration of 1 mg / mL, fully impregnated, and freeze-dried to obtain a layered phytic acid-sulfuric acid-polyaniline-doped graphene oxide.

[0041] (5) The phytic acid sulfuric acid-polyaniline-doped graphene oxide, polytetrafluoroethylene powder, glass fiber and copper powder are mixed evenly, molded (under 60MPa, held for 10min) and sintered (heated to 320℃, held for 4h) to obtain polyaniline-doped graphene oxide modified PTFE conductive composite material.

[0042] Example 2

[0043] 1) Formula: 4 parts glass fiber, 0.8 parts phytic acid sulfuric acid-polyaniline doped graphene oxide, 6 parts copper powder, 100 parts polytetrafluoroethylene;

[0044] 2) Preparation methods include:

[0045] (1) Add 4.8g of aniline to a 1mol / L sulfuric acid solution, mix well, and then add 2.8g of ammonium persulfate to react at 4℃ to obtain sulfuric acid-doped polyaniline nanofibers;

[0046] (2) The sulfuric acid-doped polyaniline nanofibers were immersed in an ammonia solution with a mass concentration of 3% for 12 hours to remove the doping, thereby obtaining basic polyaniline nanofibers.

[0047] (3) The basic polyaniline nanofibers were immersed in a 0.05 mol / L phytic acid aqueous solution and ultrasonically treated for 3 h to obtain co-doped polyaniline nanofiber material.

[0048] (4) The co-doped polyaniline nanofiber material was added to a graphene oxide dispersion with a concentration of 1 mg / mL, fully impregnated, and freeze-dried to obtain a layered phytic acid-sulfuric acid-polyaniline-doped graphene oxide.

[0049] (5) The phytic acid sulfuric acid-polyaniline-doped graphene oxide, polytetrafluoroethylene powder, glass fiber and copper powder are mixed evenly, molded (under 60MPa, held for 10min) and sintered (heated to 320℃, held for 4h) to obtain polyaniline-doped graphene oxide modified PTFE conductive composite material.

[0050] Example 3

[0051] 1) Formula: 4 parts glass fiber, 1.2 parts phytic acid sulfuric acid-polyaniline doped graphene oxide, 6 parts copper powder, 100 parts polytetrafluoroethylene;

[0052] 2) Preparation methods include:

[0053] (1) Add 4.8g of aniline to a 1mol / L sulfuric acid solution, mix well, and then add 2.8g of ammonium persulfate to react at 4℃ to obtain sulfuric acid-doped polyaniline nanofibers;

[0054] (2) The sulfuric acid-doped polyaniline nanofibers were immersed in an ammonia solution with a mass concentration of 3% for 12 hours to remove the doping, thereby obtaining basic polyaniline nanofibers.

[0055] (3) The basic polyaniline nanofibers were immersed in a 0.05 mol / L phytic acid aqueous solution and ultrasonically treated for 3 h to obtain co-doped polyaniline nanofiber material.

[0056] (4) The co-doped polyaniline nanofiber material was added to a graphene oxide dispersion with a concentration of 1 mg / mL, fully impregnated, and freeze-dried to obtain a layered phytic acid-sulfuric acid-polyaniline-doped graphene oxide.

[0057] (5) The phytic acid sulfuric acid-polyaniline-doped graphene oxide, polytetrafluoroethylene powder, glass fiber and copper powder are mixed evenly, molded (under 60MPa, held for 10min) and sintered (heated to 320℃, held for 4h) to obtain polyaniline-doped graphene oxide modified PTFE conductive composite material.

[0058] Comparative Example 1

[0059] It uses high-purity PTFE with a median particle size of 180±80um and a bulk density of 500±100.

[0060] Comparative Example 2

[0061] The difference from Example 1 is that only sulfuric acid is used to dope polyaniline, and steps (2) and (3) are omitted.

[0062] Comparative Example 3

[0063] The difference from Example 1 is that only phytic acid is used to dope polyaniline. In step (1), 0.05 mol / L phytic acid aqueous solution is used instead of 1 mol / L sulfuric acid solution, and steps (2) and (3) are omitted.

[0064] Comparative Example 4

[0065] The difference from Example 1 is that naphthalenesulfonic acid is used instead of phytic acid.

[0066] Comparative Example 5

[0067] The difference from Example 1 is that Lewis acid is used instead of phytic acid.

[0068] The product's performance was tested according to national standards, and the test results are shown in Table 1.

[0069] Table 1 Performance Test Results

[0070]

[0071]

[0072] Therefore, this invention effectively improves the conductivity, tensile strength, and elongation at break of PTFE conductive composite materials by modifying polyaniline-doped graphene oxide. Compared with other protic acids, the co-doping with phytic acid and sulfuric acid can better improve the dispersibility of polyaniline-doped graphene oxide in polytetrafluoroethylene (PTFE) granules, resulting in superior conductivity and mechanical properties.

[0073] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A polyaniline-doped graphene oxide-modified PTFE conductive composite material, characterized in that, It is composed of the following raw materials in weight percentage: 3-5 parts glass fiber, 0.5-1.5 parts phytic acid sulfuric acid-polyaniline doped graphene oxide, 4-8 parts copper powder, and 100 parts polytetrafluoroethylene. The preparation method of phytic acid-sulfuric acid-polyaniline-doped graphene oxide includes: Co-doping of polyaniline with phytic acid and sulfuric acid yielded co-doped polyaniline nanofiber materials. The co-doped polyaniline nanofiber material was used to dope graphene oxide to obtain phytic acid-sulfuric acid-polyaniline-doped graphene oxide. The specific steps of the co-doping include: Aniline was added to a sulfuric acid solution and mixed thoroughly. Then ammonium persulfate was added and the mixture was allowed to react at 4-5°C to obtain sulfuric acid-doped polyaniline nanofibers. The sulfuric acid-doped polyaniline nanofibers were immersed in an ammonia solution with a mass concentration of 3%-4% for dedoping for 12-16 hours to obtain basic polyaniline nanofibers. The basic polyaniline nanofibers were immersed in a 0.05-0.08 mol / L phytic acid aqueous solution and ultrasonically treated for 3-4 hours to obtain co-doped polyaniline nanofiber materials. The co-doped polyaniline nanofiber material was added to a graphene oxide dispersion with a concentration of 1-5 mg / mL, thoroughly impregnated, and freeze-dried to obtain a layered phytic acid-sulfuric acid-polyaniline-doped graphene oxide.

2. A method for preparing the polyaniline-doped graphene oxide-modified PTFE conductive composite material as described in claim 1, characterized in that, include: Co-doping of polyaniline with phytic acid and sulfuric acid yielded co-doped polyaniline nanofiber materials. The co-doped polyaniline nanofiber material was used to dope graphene oxide to obtain phytic acid-sulfuric acid-polyaniline-doped graphene oxide. The phytic acid-sulfuric acid-polyaniline-doped graphene oxide, polytetrafluoroethylene powder, glass fiber, and copper powder are mixed evenly, molded, and sintered to obtain a polyaniline-doped graphene oxide-modified PTFE conductive composite material.

3. The preparation method of the polyaniline-doped graphene oxide-modified PTFE conductive composite material as described in claim 2, characterized in that, The mass ratio of ammonium persulfate to aniline is 2.8-3:4.8-5.

4. The preparation method of the polyaniline-doped graphene oxide-modified PTFE conductive composite material as described in claim 2, characterized in that, The concentration of the graphene oxide solution is 0.5-1.5 mg / mL.

5. The method for preparing the polyaniline-doped graphene oxide-modified PTFE conductive composite material as described in claim 2, characterized in that, The molding condition is 60. Under 66MPa conditions, pressure holding for 5 10 minutes.

6. The method for preparing the polyaniline-doped graphene oxide-modified PTFE conductive composite material as described in claim 2, characterized in that, The sintering conditions are sintering at 320℃-370℃ for 2-4 hours.

7. The method for preparing the polyaniline-doped graphene oxide-modified PTFE conductive composite material as described in claim 2, characterized in that, The preparation method of graphene oxide is the modified Hummers method.

8. The polyaniline-doped graphene oxide-modified PTFE conductive composite material prepared by the method according to any one of claims 2-7.

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