A modification method for realizing the electrical conductivity of basalt fiber

Abstract

The application discloses a modification method for realizing the conductivity of basalt fiber. The method forms a conductive polymer on the surface of the basalt fiber through an in-situ polymerization method, so that the basalt fiber is endowed with conductivity. The method can control the particle size of the conductive polymer, the coating thickness and the conductivity of the basalt fiber by adjusting experimental parameters such as the types and concentrations of monomers, oxidants and dopants and the polymerization reaction time. The method is simple and efficient in manufacturing process, and is strong in controllability of structure and performance. The modified basalt fiber has good conductivity, and the resistivity of the basalt fiber is adjustable in the range of 1~10 ‑3 Ω·cm, which widens the application of the basalt fiber in the fields of electromagnetic shielding and electrostatic protection. Moreover, the method does not damage the structure of the fiber itself while realizing the conductivity of the basalt fiber, and improves the mechanical performance of the basalt fiber to a certain extent.

Description

Technical Field

[0001] This invention belongs to the field of basalt fiber modification technology, specifically relating to a modification method for achieving electrical conductivity in basalt fibers. Background Technology

[0002] Basalt fiber is made from basalt ore. The ore is crushed, added to a melting furnace, and melted at 1450–1700℃ to produce a glassy molten liquid. This liquid is then drawn into continuous fibers using a platinum-rhodium alloy spinneret. Throughout the entire production process, basalt fiber does not release any toxic or harmful substances or gases, thus its production does not cause environmental pollution and is hailed as a "new type of environmentally friendly fiber for the 21st century." On the other hand, with the widespread application of fiber-reinforced composites in civil engineering, transportation, aerospace, and other fields, the recyclability of fibers has gradually gained attention. Compared to carbon fiber, which is difficult to recycle, basalt fiber is made from natural basalt rock. Therefore, waste basalt fiber can be directly recycled, resulting in a high recycling rate, which contributes to the sustainable development of materials. Furthermore, basalt fiber possesses many excellent properties, such as excellent tensile properties (tensile strength reaching 3000–4840 MPa), strong corrosion resistance and chemical stability, good thermal stability, and electrical insulation. Basalt fiber reinforced composite materials have been widely used in aerospace, automotive and shipbuilding, construction, petrochemical, and sporting goods industries.

[0003] With the rapid development of cutting-edge scientific fields such as energy electronics and space technology, the electromagnetic properties of materials are becoming increasingly important. However, basalt fiber is an insulating material with a resistivity reaching 10⁻⁶. 11 The low conductivity (Ω·cm) of basalt fibers limits their application in electromagnetic shielding and electrostatic protection, making the achievement of conductivity in basalt fibers of great significance. Currently, research on developing conductivity in basalt fibers is limited. Patent application CN 108218216 A proposes a method for preparing conductive basalt fibers. This method uses chemical vapor deposition (CVD) to deposit carbon nanomaterials on the surface of basalt fibers, thereby achieving conductivity. This method can obtain a uniformly deposited carbon nanolayer on the fiber surface; however, CVD is performed at temperatures of 500-1000℃, which may damage the basalt fiber structure, thus reducing its mechanical properties. Summary of the Invention

[0004] To address the above problems and shortcomings in this field, the present invention provides a method for modifying basalt fibers to achieve conductivity. This method involves forming a conductive polymer on the surface of basalt fibers through in-situ polymerization, thereby imparting conductivity to the basalt fibers. The method allows for the control of the conductive polymer particle size, coating thickness, and conductivity of the basalt fibers by adjusting experimental parameters such as the type and concentration of monomers, oxidants, and dopants, as well as the polymerization reaction time. This method is simple, efficient, and offers strong controllability in structure and properties. The modified basalt fibers exhibit good conductivity, with a resistivity ranging from 1 to 10⁻⁶. -3 The adjustable Ω·cm range broadens the application of basalt fibers in electromagnetic shielding, electrostatic protection, and other fields. Furthermore, this method achieves conductivity in basalt fibers without damaging the fiber structure, and also improves the mechanical properties of basalt fibers to a certain extent.

[0005] A method for modifying basalt fibers to improve electrical conductivity includes the following steps:

[0006] (1) Wash the basalt fiber with anhydrous ethanol and deionized water 3 to 5 times to remove surface impurities, and then soak it in a conductive polymer monomer solution for adsorption for a period of time, keeping the system temperature within a certain range.

[0007] (2) Prepare a mixture of oxidant and dopant in a certain proportion, slowly add the mixture to the monomer solution soaking basalt fiber, and polymerize for a period of time. Keep the system temperature within a certain range throughout the polymerization process.

[0008] (3) Take out the basalt fiber and dry the modified basalt fiber at 60°C to constant weight to obtain conductive basalt fiber.

[0009] In the modification method for achieving conductivity of basalt fibers, in step (1), the molar ratio of conductive polymer monomer to oxidant is 0.1 to 3, the adsorption time is 0.5 to 3 h, the system temperature is controlled at 0 to 10 °C, and the volume of the solution should completely immerse the basalt fibers.

[0010] In the modification method for achieving conductivity of basalt fibers, in step (2), the concentration of the oxidant solution is 0.01 mol / L to 2.5 mol / L, the molar ratio of dopant to monomer is 0 to 2, the polymerization reaction time is 0.5 to 48 h, and the system temperature is controlled at 0 to 10 °C.

[0011] In the modification method for achieving conductivity of basalt fibers, the conductive polymer in step (1) includes one of polyaniline (PANI) and polypyrrole (PPy); therefore, the corresponding conductive polymer monomer is one of aniline (An) and pyrrole (Py).

[0012] In the modification method for achieving conductivity of basalt fibers, in step (2), the oxidant is independently selected from ammonium persulfate (APS) and ferric chloride (FeCl3), and the dopant is independently selected from sodium sulfosalicylate (NaSSA) and sodium dodecylbenzenesulfonate (SDBS).

[0013] The beneficial effects of this invention are at least reflected in:

[0014] This invention provides a method for modifying basalt fibers to achieve electrical conductivity. The method involves forming a conductive polymer on the surface of basalt fibers through in-situ polymerization, thereby imparting conductivity to the basalt fibers. The method allows for the control of the conductive polymer particle size, coating thickness, and conductivity of the basalt fibers by adjusting experimental parameters such as the type and concentration of monomers, oxidants, and dopants, as well as the polymerization reaction time.

[0015] This method offers a simple and efficient manufacturing process with strong controllability in structure and performance. The modified basalt fibers exhibit excellent electrical conductivity, with a resistivity adjustable within the range of 1–10⁻³ Ω·cm, broadening the application of basalt fibers in electromagnetic shielding and electrostatic protection. Furthermore, this method achieves conductivity in basalt fibers without damaging the fiber structure and, to a certain extent, improves the mechanical properties of the basalt fibers. Details are as follows:

[0016] 1. This invention employs an in-situ polymerization method to modify basalt fibers for electrical conductivity without damaging their structure. Compared to the patent application CN 108218216 A, which proposes "a method for preparing conductive basalt fibers," the conductive basalt fibers prepared by this method exhibit better electrical conductivity, do not damage the fiber structure, and improve the tensile strength of the fibers to a certain extent, thus possessing broader application value.

[0017] 2. The conductive basalt fibers provided by this invention, which were originally modified by polymerization, have strong controllability. The particle size of the conductive polymer, the coating thickness, and the conductivity of the basalt fibers can be controlled by adjusting experimental parameters such as the type and concentration of monomers, oxidants, and dopants, as well as the polymerization reaction time. The resistivity can range from 1 to 10 ohms depending on the experimental conditions. -3 Ω·cm is used for regulation.

[0018] 3. Compared to basalt fiber, the resistivity of basalt fiber modified with conductive polymer is reduced from 10... 11 Ω·cm can be reduced to 10 -3 The Ω·cm value gives basalt fibers good electrical conductivity; due to the filling effect of conductive polymer particles on fiber defects, the tensile strength of basalt fibers after modification can be increased by 20%.

[0019] 4. This invention broadens the application of basalt fiber in electromagnetic shielding, electrostatic protection, and other fields. The modification process is simple, suitable for large-scale preparation, does not introduce corrosive chemicals, and has favorable preparation conditions. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 Example 1 shows a comparison of the resistivity of basalt fibers with different molar ratios of polypyrrole (PPy) and ferric chloride (FeCl3) oxidant, using polypyrrole (PPy) as the conductive polymer.

[0022] Figure 2 Example 2 shows a comparison of the resistivity of basalt fibers with polypyrrole (PPy) as the conductive polymer and sodium sulfosalicylate (NaSSA) and pyrrole (Py) at different molar ratios.

[0023] Figure 3 Example 3 shows the modification of basalt fibers using polypyrrole (PPy) as a conductive polymer, with a comparison of the tensile strength of the monofilaments before and after modification.

[0024] Figure 4 This is a schematic diagram of the reaction in this invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1

[0027] Basalt fiber cloth (BF) was washed 3–5 times with anhydrous ethanol and deionized water, and then immersed in pyrrole (Py) monomer solutions of 0.5 mol / L, 1 mol / L, 2 mol / L, and 3 mol / L for adsorption for 30 min, maintaining the system temperature at 0℃. Simultaneously, a 1 mol / L ferric chloride (FeCl3) oxidant solution was prepared (the molar ratio of pyrrole to ferric chloride was 0.5, 1, 2, and 3, respectively). After adsorption, the ferric chloride solution was slowly added to the pyrrole monomer solution soaking the basalt fiber using a dropper. The polymerization reaction was carried out for 3 h, maintaining the system temperature at 0℃ throughout the process. The polymerized basalt fiber cloth was dried at 60℃ to constant weight to obtain polypyrrole-modified basalt fiber, which was designated as PPy / BF-0.5, PPy / BF-1, PPy / BF-2, and PPy / BF-3 according to the different pyrrole monomer concentrations. The thickness of the basalt fiber cloth was measured at five different locations, and the average value was taken as the thickness of the basalt fiber cloth. The sheet resistance of the basalt fiber cloth at five different locations was measured using the four-probe method, and the average value was taken as the sheet resistance of the basalt fiber cloth. The resistivity of the basalt fiber was calculated.

[0028] The results are as follows Figure 1 As shown, the resistivity of basalt fibers first decreases and then increases with the increase of the molar ratio of pyrrole to ferric chloride. The resistivity is lowest when the molar ratio of pyrrole to ferric chloride is 2.

[0029] Example 2

[0030] Basalt fiber cloth (BF) was washed 3–5 times with anhydrous ethanol and deionized water, and then immersed in a 2 mol / L pyrrole (Py) monomer solution for adsorption for 30 min, maintaining the system temperature at 0℃. Simultaneously, mixed solutions of 1 mol / L oxidant ferric chloride (FeCl3) and 0 mol / L, 0.1 mol / L, 0.2 mol / L, 1 mol / L, and 2 mol / L dopant sodium sulfosalicylate (NaSSA) were prepared (the molar ratio of dopant (sodium sulfosalicylate) to pyrrole was 0, 0.05, 0.1, 0.5, and 1, respectively). After adsorption, the mixture containing ferric chloride and sodium sulfosalicylate was slowly added to the pyrrole monomer solution soaking the basalt fiber using a dropper. The polymerization reaction was carried out for 3 h, maintaining the system temperature at 0℃ throughout the process. The polymerized basalt fiber cloth was dried at 60 degrees Celsius to constant weight to obtain polypyrrole-modified basalt fiber. Depending on the molar ratio of dopant to pyrrole, the fibers were designated as PPy / BF-2(0), PPy / BF-2(0.05), PPy / BF-2(0.1), PPy / BF-2(0.5), and PPy / BF-2(1). The thickness of the basalt fiber cloth was measured at five different locations, and the average value was taken as the thickness of the basalt fiber cloth. The sheet resistance of the basalt fiber cloth at five different locations was measured using the four-probe method, and the average value was taken as the sheet resistance of the basalt fiber cloth. The resistivity of the basalt fiber was calculated.

[0031] The results are as follows Figure 2 As shown, the resistivity of basalt fibers decreases with increasing dopant content. When the molar ratio of dopant to pyrrole is 0.1, 0.5, and 1, the resistivity remains almost unchanged.

[0032] Example 3

[0033] Basalt fiber (BF) was washed 3–5 times with anhydrous ethanol and deionized water, then immersed in a 2 mol / L pyrrole (Py) monomer solution for adsorption for 30 min, maintaining the system temperature at 0°C. Simultaneously, a 1 mol / L ferric chloride (FeCl3) oxidant solution was prepared. After adsorption, the ferric chloride solution was slowly added to the pyrrole monomer solution soaking the basalt fiber using a dropper. The polymerization reaction was carried out for 3 h, maintaining the system temperature at 0°C throughout the process. The polymerized basalt fiber cloth was dried at 60°C to constant weight to obtain polypyrrole-modified basalt fiber, denoted as PPy / BF. Thirty samples of basalt fiber monofilaments, both before and after modification, were prepared on U-shaped paper. The tensile strength of the basalt fiber monofilaments was measured using a monofilament tensile tester, and the fiber diameter was measured using a microscope, thereby calculating the tensile strength of the basalt fiber monofilaments.

[0034] The results are as follows Figure 3As shown, the modified basalt fiber (PPy / BF) has better mechanical properties than the unmodified basalt fiber (BF), meaning that the tensile strength is not reduced but improved.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for modifying basalt fibers to achieve electrical conductivity, characterized in that, Including the following steps: (1) Basalt fibers are washed with anhydrous ethanol and deionized water 3 to 5 times to remove surface impurities, and then immersed in a conductive polymer monomer solution for adsorption while controlling the temperature; the conductive polymer monomer is pyrrole. (2) Prepare a mixture of oxidant and dopant, and slowly add the mixture to the pyrrole monomer solution soaking the basalt fiber to carry out the polymerization reaction; (3) Take out the basalt fiber and dry the modified basalt fiber at 60°C to constant weight to obtain conductive basalt fiber; Wherein: the molar ratio of the conductive polymer monomer in step (1) to the oxidant in step (2) is 0.1~3, the adsorption time is 0.5~3h, the system temperature is controlled at 0~10°C, and the volume of the solution should completely immerse the basalt fiber; In step (2), the concentration of the oxidant solution is 0.01 mol / L to 2.5 mol / L, the oxidant is ferric chloride, the dopant is sodium sulfosalicylate, the molar ratio of the dopant to the monomer is 0.1-1, the polymerization reaction time is 0.5-48 h, and the system temperature is controlled at 0-10°C.

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