Method and system for enhancing interface performance of optical fiber composite insulator

Abstract

The invention discloses a method and a system for enhancing the interface performance of an optical fiber composite insulator. The method comprises the following steps: firstly, introducing a polar functional group on the surface of an optical fiber through plasma pretreatment and forming micro-etching; then coating a nano SiO2 transition layer on the surface of the optical fiber by adopting a sol-gel method; and finally, implanting the treated optical fiber into a composite core matrix material containing a silane coupling agent, and curing and molding. Through the synergistic effect of physical anchoring and chemical bonding, the interface bonding strength between the optical fiber and the core body is remarkably enhanced, the tensile strength of the composite material is improved from 35.096 MPa to 52.117 MPa, the bending strength of the composite material is improved from 60.124 MPa to 78.946 MPa, meanwhile, the breakdown strength is remarkably improved, the leakage current is remarkably reduced, the interface electric field distribution is effectively improved, and the service life of the composite material is prolonged. And the mechanical performance, the electrical insulation performance and the long-term operation reliability of the optical fiber composite insulator are improved.

Description

Technical Field

[0001] This invention belongs to the field of composite material technology, and particularly relates to a method and system for enhancing the interface properties of optical fiber composite insulators. Background Technology

[0002] Insulators are key components in power systems that ensure reliable power transmission. Among them, post composite insulators are gradually replacing traditional ceramic insulators due to their advantages of light weight, ease of maintenance, and excellent external insulation performance. Their core structure, the insulator core, must not only bear mechanical loads but also provide stable electrical insulation strength. Fiber optic composite insulators, as core equipment in power transmission and transformation systems that combine high-voltage insulation and signal detection capabilities, are widely used in ultra-high voltage and extra-high voltage transmission lines and substations at all levels. Their superior performance and operational stability directly determine the safe and reliable power supply of the power grid.

[0003] However, the interface between the fiber optic composite insulator core rod and the fiber optic cable is susceptible to aging and degradation due to the combined effects of multiple factors, including moisture, ultraviolet radiation, temperature and humidity cycling, and strong electric fields. Specifically, this manifests as defects such as micropores, weakened intermolecular forces, and viscous failure in the bonding layer between the fiber and the core rod matrix. These defects further distort the electric field distribution in the interface region, increasing the risk of partial discharge, interface breakdown, and even insulator failure. Therefore, strengthening the fiber interface to ensure a tight bond between different insulating materials can effectively improve the insulation performance and operational reliability of fiber optic composite insulators.

[0004] Currently, domestic research on fiber-optic composite insulators largely focuses on overall insulation performance and structural design, while systematic solutions to the fiber-core interface problem are scarce. Existing technologies mostly remain at the level of optimizing macroscopic insulation and mechanical properties, lacking in-depth research and effective solutions regarding interface microstructure, material compatibility, and long-term durability. Because the fiber sheath is typically made of hydrophobic material with a smooth surface and strong chemical inertness, lacking reactive functional groups, its bonding with the core relies mainly on weak van der Waals forces or physical adsorption forces. Insufficient interfacial bonding limits the effective transfer of load and makes it prone to interfacial delamination under mechanical or environmental stress, thus affecting the overall mechanical and electrical properties of the composite material.

[0005] In conclusion, conducting research on the interface treatment of optical fiber and core rod in optical fiber composite insulators and analyzing key performance parameters is of great significance for breaking through the current research bottlenecks in China and improving the overall performance and service life of optical fiber composite insulators. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention proposes a method and system for enhancing the interface performance of optical fiber composite insulators.

[0007] To achieve the above objectives, the present invention provides a method for enhancing the interface performance of optical fiber composite insulators, comprising the following steps: Step 1: Perform plasma treatment on the surface of the optical fiber to introduce polar functional groups and form micro-etching. Step 2: Using the sol-gel method, a nano-SiO2 coating is coated on the surface of the plasma-treated optical fiber to construct a nanomaterial transition layer; Step 3: Prepare a composite core matrix material containing a silane coupling agent; Step 4: Insert the optical fiber coated with nano-SiO2 into the composite core matrix material and then cure it.

[0008] Furthermore, in step one, the plasma treatment power is 50W and the treatment time is 120s; the polar functional groups include carboxyl and hydroxyl groups.

[0009] Furthermore, in step two, coating with nano-SiO2 specifically includes: immersing the plasma-treated optical fiber in a nano-SiO2 dispersion for 2 hours. The nano-SiO2 dispersion is prepared by ultrasonically dispersing nano-SiO2 powder in anhydrous ethanol, and its pH value is adjusted to 6.5.

[0010] Furthermore, the mass fraction of nano-SiO2 in the nano-SiO2 dispersion is 1% to 3%.

[0011] Furthermore, the mass fraction of nano-SiO2 in the nano-SiO2 dispersion is 2%.

[0012] Furthermore, in step three, the composite core matrix material is composed of E51 type epoxy resin, methyl hexahydrophthalic anhydride, accelerator 2,4,6-tris(dimethylaminomethyl)phenol, polyethyl methacrylate polymer hollow microspheres, and KH-560 silane coupling agent.

[0013] Further, the molar ratio of the E51 type epoxy resin to methylhexahydrophthalic anhydride is 5:4; the mass of the accelerator is 1.0% of the mass of the epoxy resin; the mass of the polyethyl methacrylate polymer hollow microspheres is 2.0% of the mass of the epoxy resin; and the mass of the KH-560 silane coupling agent is 2% of the mass of the epoxy resin.

[0014] The present invention also provides an optical fiber composite insulator prepared by the method described above, comprising: Insulator core; Optical fibers implanted inside the insulator core; and the interface reinforcement structure located between the optical fiber and the insulator core; The interface enhancement structure includes polar functional groups and a micro-etched layer formed on the surface of an optical fiber by plasma treatment, and a nano-SiO2 transition layer constructed on the micro-etched layer by a sol-gel method.

[0015] The present invention also provides an interface performance enhancement system for optical fiber composite insulators, for implementing the method described above, comprising: Surface pretreatment unit for plasma treatment of optical fibers; A coating unit is used to coat a nano-SiO2 coating onto the surface of a treated optical fiber using a sol-gel method. The material preparation unit is used to prepare composite core matrix materials containing silane coupling agents; And a curing unit, used to combine and cure the processed optical fiber with the composite core matrix material.

[0016] Compared with the prior art, the present invention has the following advantages and technical effects: This invention designs and constructs a highly active interface with a nanomaterial transition layer by pretreating optical fibers with plasma and then coating the fiber surface with nano-SiO2 using a sol-gel method. The nanomaterial transition layer structure provides stronger physicochemical interactions, such as mechanical interlocking and covalent bonding, for the interfacial adhesion of the composite material. Experimental results show that, compared with the untreated material, the tensile strength of the composite material coated with 2wt% nano-SiO2 increased from 35.096 MPa to 52.117 MPa, an increase of 48.5%; the flexural strength increased from 60.124 MPa to 78.946 MPa, an increase of 31.3%. Furthermore, due to the improved interfacial adhesion, the dynamic mechanical properties and performance stability of the composite material were also significantly improved. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a traditional optical fiber composite insulator core.

[0018] Figure 2 This is a process flow diagram of the method for enhancing the interface performance of optical fiber composite insulators according to the present invention.

[0019] Figure 3 This is a comparison chart of the breakdown strength test results of different embodiments and control examples.

[0020] Figure 4 This is a comparison chart of leakage current test results for different embodiments and control examples.

[0021] Figure 5 This is a comparison chart of the tensile strength test results of different embodiments and control examples. Detailed Implementation

[0022] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0023] All raw materials used in this invention are not particularly limited in their source; they can be purchased from the market or prepared using conventional methods known to those skilled in the art.

[0024] There are no particular restrictions on the purity of any of the raw materials used in this invention. However, this invention preferably uses raw materials of analytical grade or purity commonly used in the field of chemical synthesis.

[0025] Comparison Example To clearly demonstrate the performance improvement brought about by the technical solution of the present invention, a comparative example without the interface enhancement method of the present invention is first provided.

[0026] Reference Figure 1 The schematic diagram of a traditional optical fiber composite insulator core structure is shown. Its preparation process is as follows: E51 type epoxy resin and curing agent methylhexahydrophthalic anhydride (MHHPA) are weighed in a 5:4 molar ratio. Then, 1.0% of the epoxy resin mass of accelerator 2,4,6-tris(dimethylaminomethyl)phenol (DMP-30) and 2.0% of the epoxy resin mass of polymethyl methacrylate (PMMA) hollow microspheres are added as lightweight fillers. The mixture is placed in a vacuum planetary stirrer and stirred at 500 r / min for 5 minutes under vacuum to ensure thorough and uniform mixing of all components. Subsequently, the mixture is placed in a vacuum drying oven and heated at 60℃ for 2 hours to obtain the pre-cured lightweight composite core matrix material.

[0027] Plain optical fibers without any interface enhancement treatment are fixed in a specific mold and extend from both ends of the mold. The prepared pre-cured lightweight composite material is then filled into the mold, completely covering the optical fiber. Finally, the mold is placed in a heating environment at 100°C for 2.5 hours to allow the composite material to fully cure, thus obtaining the fiber-optic composite insulating core after optical fiber implantation. The cured samples need to be cut into standard shapes and sizes for subsequent performance testing.

[0028] Examples 1-3 The method for enhancing the interface performance of fiber optic composite insulators provided by this invention has a core process that can be referred to. Figure 1 The process flow diagram shown includes the following steps: Fiber optic surface cleaning and pretreatment: First, the fiber optic cable is ultrasonically cleaned in ethanol for 2 hours to thoroughly remove grease, dust, and other contaminants adhering to the surface. After cleaning, the fiber optic cable is transferred to a vacuum drying oven at 60°C for 20 minutes to remove residual ethanol.

[0029] Plasma surface activation: Cleaned and dried optical fibers are placed in an atmospheric plasma treatment device. The treatment power is set to 50W and the treatment time to 120 seconds. Under these conditions, the plasma bombards the surface of the optical fiber, forming uniformly distributed micro-etchings (micro-pits) to provide physical anchoring points. On the other hand, it breaks the inert chemical bonds on the surface of the optical fiber sheath and introduces polar functional groups such as carboxyl groups (-COOH) and hydroxyl groups (-OH), significantly improving the chemical activity and wettability of the optical fiber surface.

[0030] Construction of the nano-SiO2 transition layer: This step employs the sol-gel method to coat the activated optical fiber surface with a nano-SiO2 transition layer. First, nano-SiO2 dispersions with different mass fractions (1%, 2%, and 3%) were prepared: The corresponding mass of nano-SiO2 powder was added to anhydrous ethanol, and the pH of the dispersion was adjusted to 6.5 with dilute hydrochloric acid or ammonia. Then, the dispersion was ultrasonically dispersed for 15 minutes to obtain a stable and uniform dispersion. Subsequently, the plasma-treated optical fiber was immersed in the dispersion for 2 hours to allow for sufficient adsorption and deposition of the nanoparticles. After immersion, the optical fiber was removed, dried at 60°C for 20 minutes to remove most of the solvent, and then allowed to stand at room temperature for 4 hours to complete the gelation process, ultimately forming a stable nano-SiO2 coating on the optical fiber surface.

[0031] Preparation and curing of composite core material: E51 type epoxy resin and curing agent methylhexahydrophthalic anhydride (MHHPA) were weighed in a molar ratio of 5:4. Then, 1.0% (by mass) of accelerator DMP-30, 2.0% (by mass) of PMMA hollow microspheres, and 2% (by mass) of KH-560 silane coupling agent stock solution were added. The addition of the silane coupling agent is crucial. The siloxane group at one end of its molecule can undergo hydrolytic condensation with the silanol groups on the surface of the nano-SiO2 coating to form a strong Si-O-Si covalent bond; the epoxy group at the other end can undergo a ring-opening reaction with the epoxy groups in the matrix resin, thereby constructing a solid "covalent bridge" between the inorganic nano-coating and the organic resin matrix, greatly enhancing the interfacial bonding and compatibility.

[0032] The mixture was placed in a vacuum planetary stirrer and stirred at 500 r / min for 5 minutes under vacuum to ensure uniform dispersion of all components, especially the nanoscale additives. Subsequently, the mixture was placed in a vacuum drying oven and heated at 60°C for 2 hours for pre-curing, resulting in a pre-cured lightweight composite core matrix material with good processability.

[0033] The optical fiber prepared in step 3, with a nano-SiO2 transition layer coated on its surface, is fixed in a mold and extends from both ends. The prepared pre-cured lightweight composite material is then filled into the mold, ensuring complete coverage of the interface-enhanced optical fiber. Finally, the mold is placed in a heating environment at 100°C for 2.5 hours to complete the final curing, obtaining the high-performance optical fiber composite insulating core described in this invention. The cured composite material samples are cut into standard shapes and sizes and subjected to various performance tests.

[0034] Performance Testing and Result Analysis To quantitatively evaluate the effectiveness of the technical solution of this invention, key performance tests were conducted on the samples prepared in the above-mentioned comparative examples and Examples 1 (1% nano-SiO2), 2 (2% nano-SiO2), and 3 (3% nano-SiO2). The results are as follows: Breakdown strength: such as Figure 3 As shown, the breakdown strength of the control example was 23.23 kV / mm. After employing the method of the present invention, the breakdown strength of Example 1 increased to 26.20 kV / mm, Example 2 to 29.06 kV / mm, and Example 3 to 27.50 kV / mm. This indicates that interface enhancement treatment, especially the 2% nano-SiO2 coating scheme of Example 2, can effectively improve the interfacial electric field distribution and significantly improve the breakdown resistance of the material.

[0035] Leakage current: such as Figure 4 As shown, under the same test conditions, the leakage current of the control sample was 58.31 μA. The leakage currents of Examples 1, 2, and 3 decreased to 56.26 μA, 53.80 μA, and 55.64 μA, respectively. The reduction in leakage current indicates a decrease in interface defects, suppression of charge migration, and enhanced insulation performance.

[0036] Tensile strength: such as Figure 5 As shown, the tensile strength of the control example was 35.096 MPa. After interface reinforcement treatment, the tensile strength of Example 1 reached 46.327 MPa, Example 2 reached 52.117 MPa (an increase of 48.5% compared to the control), and Example 3 reached 48.075 MPa. This fully demonstrates the significant enhancement effect of plasma activation and the nano-SiO2 transition layer on interfacial bonding, enabling stress to be transferred more effectively from the resin matrix to the optical fiber when the material is subjected to tensile load.

[0037] Flexural strength: The flexural strength of the control sample was 60.124 MPa. The flexural strengths of Examples 1, 2, and 3 were increased to 73.467 MPa, 78.946 MPa (an increase of 31.3% compared to the control sample), and 75.001 MPa, respectively. The significant increase in flexural strength further verifies that the treated interface can effectively resist shear stress, prevent interfacial delamination, and thus improve the overall rigidity and load-bearing capacity of the composite material.

[0038] in conclusion The comparison between the above specific embodiments and comparative examples clearly demonstrates that this invention, through an interface enhancement method combining "plasma pretreatment" and a "nano-SiO2 transition layer," systematically solves the technical challenges of weak interfacial bonding, easy aging, and easy electric field distortion between optical fibers and the core rod. Experimental data fully demonstrate that this method not only significantly improves the mechanical properties (tensile and bending strength) of optical fiber composite insulators but also significantly enhances their electrical properties (breakdown strength and leakage current), especially when the mass fraction of nano-SiO2 coating is 2% (Example 2), resulting in optimal overall performance. This provides a clear and effective technical path for preparing high-performance, high-reliability optical fiber composite insulators.

[0039] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method of enhancing the performance of the interface of an optical fiber composite insulator, characterized in that, The method comprises the following steps: Step 1: plasma treatment is performed on the surface of the optical fiber to introduce polar functional groups and form micro-etching on the surface of the optical fiber; Step 2: a nano-SiO2 coating is coated on the surface of the optical fiber after the plasma treatment by using a sol-gel method to construct a nano-material transition layer; Step 3: a composite core matrix material containing a silane coupling agent is prepared; Step 4: the optical fiber coated with the nano-SiO2 coating is implanted into the composite core matrix material, and then solidified and formed.

2. The method of claim 1, wherein the interface performance of the optical fiber composite insulator is enhanced by, In the step 1, the power of the plasma treatment is 50 W, and the treatment time is 120 s; the polar functional groups include carboxyl and hydroxyl groups.

3. The method of claim 1, wherein the interface performance of the optical fiber composite insulator is enhanced by, In the step 2, the coating of the nano-SiO2 coating specifically comprises: the optical fiber after the plasma treatment is soaked in a nano-SiO2 dispersion liquid for 2 hours, the nano-SiO2 dispersion liquid is prepared by ultrasonic dispersion of nano-SiO2 powder in anhydrous ethanol, and the pH value is adjusted to 6.

5.

4. The method of claim 3, wherein the interface performance of the optical fiber composite insulator is enhanced by, The mass fraction of the nano-SiO2 in the nano-SiO2 dispersion liquid is 1% to 3%.

5. The method of claim 4, wherein the interface performance of the optical fiber composite insulator is enhanced by, The mass fraction of the nano-SiO2 in the nano-SiO2 dispersion liquid is 2%.

6. The method of claim 1, wherein the interface performance of the optical fiber composite insulator is enhanced by, In the step 3, the composite core matrix material is composed of E51 type epoxy resin, methylhexahydrophthalic anhydride, a promoter 2,4,6-tris(dimethylaminomethyl) phenol, polyethyl methacrylate hollow microspheres and KH-560 silane coupling agent.

7. The method of claim 6, wherein the interface performance of the optical fiber composite insulator is enhanced by, The molar ratio of the E51 type epoxy resin to the methylhexahydrophthalic anhydride is 5:4; the mass of the promoter is 1.0% of the mass of the epoxy resin; the mass of the polyethyl methacrylate hollow microspheres is 2.0% of the mass of the epoxy resin; and the mass of the KH-560 silane coupling agent is 2% of the mass of the epoxy resin.

8. An optical fiber composite insulator prepared by the method according to any one of claims 1 to 7, characterized in that The method comprises the following steps: An insulator core; An optical fiber implanted in the insulator core; And an interface reinforcing structure between the optical fiber and the insulator core; The interface reinforcing structure comprises polar functional groups and a micro-etching layer formed on the surface of the optical fiber by plasma treatment, and a nano-SiO2 transition layer constructed on the micro-etching layer by a sol-gel method.

9. An interface performance enhancement system for optical fiber composite insulators for implementing the method according to any one of claims 1 to 7, characterized in that, The method comprises the following steps: A surface pretreatment unit for plasma treatment of the optical fiber; A coating unit for coating a nano-SiO2 coating on the surface of the treated optical fiber by a sol-gel method; A material preparation unit for preparing a composite core matrix material containing a silane coupling agent; And a solidification unit for combining the treated optical fiber with the composite core matrix material and solidifying.

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