Method for preparing composite material by loading nanoparticles into fiber-epoxy resin and application thereof

Abstract

The application discloses a method for preparing a composite material by loading nanometer particles on a fiber and filling an epoxy resin and application thereof. The method is characterized by the following steps: a semiconductor nanometer particle SiC is loaded on a filler network structure of a glass fiber fabric surface; and a plasma treatment technology is combined to activate the fiber surface, so that a stable and efficient fiber loading nanometer particle structure preparation is realized. Based on the structure, an epoxy resin is infiltrated to obtain a composite material. In the composite material, the nanometer SiC particles can be used as a connecting point to form a charge dissipation path, so that the surface charge dissipation rate of the material is obviously improved, and thus the surface flashover voltage of the material is improved.

Description

Technical Field

[0001] This invention belongs to the field of electrical insulation materials technology, specifically relating to a method and application for preparing composite materials by fiber-loaded nanoparticle-filled epoxy resin. Background Technology

[0002] In actual operation, epoxy composite insulation materials are prone to surface charge accumulation, leading to surface flashover discharge faults and seriously threatening equipment safety. Filler doping modification can effectively improve the surface voltage withstand performance of epoxy resin and control the surface charge and electric field distribution. However, conventional filler doping is often limited by problems such as agglomeration effects and interfacial barriers, making it difficult to obtain a stable and controllable method for controlling the surface charge of epoxy composite materials.

[0003] As research progressed, researchers discovered that constructing a stable spatial topology for the filler and building an interconnected filler network can effectively improve the charge dissipation rate on the surface of insulating materials, suppress charge accumulation, thereby alleviating the field distortion effect in local areas of the material surface and significantly improving the surface flashover voltage. To obtain an economical, efficient, and processable modification method, researchers conducted extensive studies on the selection of filler materials and the construction methods of the filler network structure. Summary of the Invention

[0004] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0005] In view of the problems existing in the above and / or prior art, the present invention is proposed.

[0006] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing composite materials by loading nanoparticles onto epoxy resin with fibers.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: including,

[0008] Nanoparticles are immersed in an aqueous epoxy resin solution, thoroughly mixed, and then coated onto pre-activated glass fibers. After drying, a fiber fabric carrying nanoparticles is obtained.

[0009] Epoxy resin, curing agent and accelerator are mixed and stirred evenly. After vacuum degassing, glass fibers are impregnated layer by layer. The fiber fabric carrying nanoparticles is placed on the top layer, and hot-pressed and cured to obtain the composite material of fiber carrying nanoparticles filled with epoxy resin.

[0010] As a preferred embodiment of the method for preparing composite materials by loading nanoparticles onto epoxy resin according to the present invention, the nanoparticles include nano-SiC, ZnO, BaTiO3, and BiFeO3.

[0011] As a preferred embodiment of the method for preparing composite materials by loading nanoparticles onto epoxy resin according to the present invention, the activation method of the pre-activated glass fiber includes arranging the ultrasonically cleaned and dried glass fiber below a plasma jet electrode, and activating the glass fiber by introducing argon gas into the jet tube and connecting a high-frequency high-voltage power supply to obtain a stable discharge plasma plume.

[0012] As a preferred embodiment of the method for preparing composite materials by fiber-loaded nanoparticle-filled epoxy resin according to the present invention, wherein the fiber fabric loaded with nanoparticles has a mass ratio of nanoparticles to glass fibers of 1 to 4: 2.24.

[0013] In a preferred embodiment of the method for preparing composite materials by fiber-loaded nanoparticle-filled epoxy resin according to the present invention, the epoxy resin is an electrical insulating epoxy resin, including E-51 type, E44 type bisphenol A epoxy resin, S186 type, and OSC type alicyclic epoxy resin; the curing agent is an anhydride curing agent, including methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, and maleic anhydride; the accelerator is an accelerator for epoxy-anhydride systems, including 2,4,6-tris(dimethylaminomethyl)phenol, benzylamine, and glycerol.

[0014] In a preferred embodiment of the method for preparing composite materials by fiber-loaded nanoparticle-filled epoxy resin according to the present invention, the mass ratio of epoxy resin, curing agent and accelerator is 80-120:60-100:1-2.

[0015] In a preferred embodiment of the method for preparing composite materials by loading nanoparticles onto epoxy resin according to the present invention, the mass ratio of the epoxy resin to the glass fiber fabric is 3-5:5-7.

[0016] As a preferred embodiment of the method for preparing composite materials by fiber-loaded nanoparticle-filled epoxy resin according to the present invention, the hot pressing molding process includes a hot pressing temperature of 80-160°C, a hot pressing pressure of 8-10 MPa, and a hot pressing time of 20-60 min.

[0017] In a preferred embodiment of the method for preparing composite materials by fiber-loaded nanoparticle-filled epoxy resin according to the present invention, the curing process includes a curing temperature of 25℃~160℃ and a curing time of 2~10h.

[0018] Another objective of this invention is to overcome the shortcomings of the prior art and provide an application for preparing composite materials by fiber-loaded nanoparticle-filled epoxy resin.

[0019] To solve the above-mentioned technical problems, the present invention provides the following technical solution: including,

[0020] Applying the composite material to the fabrication of insulating devices can effectively improve the dissipation rate of surface charge, thereby alleviating surface electric field distortion and increasing surface flashover voltage.

[0021] Beneficial effects of this invention:

[0022] (1) This invention utilizes a method for constructing a filler network structure on the surface of glass fiber fabric using semiconductor nanoparticles, combined with plasma treatment technology to activate the fiber surface, thereby achieving stable and efficient preparation of fiber-mounted nanoparticle structures.

[0023] (2) Based on this structure, the composite material obtained by impregnating epoxy resin can form a charge dissipation path with nanoparticles as the connection points, which significantly improves the surface charge dissipation rate of the material, thereby increasing its surface flashover voltage. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0025] Figure 1 This is a flowchart of the method for preparing composite materials by loading nanoparticles onto epoxy resin according to the present invention.

[0026] Figure 2 The image shows the microscopic characterization results of glass fibers with different amounts of nano-SiC loading in Example 1 of this invention.

[0027] Figure 3 The image shows the microscopic characterization results of the fiber-supported nano-SiC structure epoxy composite material in Example 1 of this invention.

[0028] Figure 4 This is a schematic diagram of the DC surface flashover test platform according to Embodiment 2 of the present invention.

[0029] Figure 5 This is a schematic diagram of the surface charge testing platform in Embodiment 2 of the present invention.

[0030] Figure 6 The graph shows the flashover voltage test results of epoxy composite materials with different amounts of nano-SiC in Example 2 of the present invention.

[0031] Figure 7 This is a graph showing the surface charge decay curves of epoxy composite materials with different amounts of nano-SiC in Example 2 of the present invention.

[0032] Figure 8 The image shows the flashover voltage Weibull distribution of glass fibers loaded with nano-SiC modified epoxy composite material in Comparative Example 1 of this invention, both before and after plasma treatment. Detailed Implementation

[0033] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0034] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0035] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0036] Example 1

[0037] Nano-SiC powder was taken into beakers at masses of 1g, 1.4g, 2g, 2.7g and 4g respectively, and an appropriate amount of deionized water was added. The mixture was stirred at room temperature for 10 min to obtain SiC suspensions of different mass concentrations.

[0038] Take 2g of water-based epoxy curing agent and 10mL of deionized water in a beaker, mix them, and stir for 20min under oil bath heating at 60℃ to obtain an aqueous curing agent solution;

[0039] Nano SiC suspensions of different mass concentrations were added to the curing agent aqueous solution, mixed and stirred for 20 min, 2 g of waterborne epoxy resin was added dropwise, stirred for 30 min under oil bath heating at 60℃, and continuously dispersed in an ultrasonic cleaner for 30 min to obtain a uniformly dispersed nano SiC / waterborne epoxy resin mixture.

[0040] Take a 20*10cm glass fiber cloth and clean it in an ultrasonic cleaner for 1 minute and dry it thoroughly. Place the dried glass fiber cloth 1cm below the plasma jet electrode, introduce argon gas at a flow rate of 2.5slm into the jet tube, then connect the high-frequency high-voltage power supply, adjust the voltage to 5.0kV and the center frequency to 50kHz to obtain a stable discharge plasma plume, and treat the glass fiber cloth for 5 minutes to fully activate its surface.

[0041] The nano-SiC / waterborne epoxy resin mixture of different concentrations was uniformly impregnated onto the surface of the activated fiberglass cloth. After impregnation, it was placed in a vacuum drying oven and dried at 80°C to obtain a fiber-loaded nano-SiC particle structure.

[0042] Weigh 14.0g of E-51 type bisphenol A epoxy resin and 11.2g of methyltetrahydrophthalic anhydride curing agent, stir in an oil bath at 60℃ for 20min, then add 0.14g of 2,4,6-tris(dimethylaminomethyl)phenol (DMP-30) as an accelerator and continue stirring for 10min. The mass ratio of the three materials is DGEBA:MTHPA:DMP-30=100:80:1;

[0043] Vacuum degassing treatment is performed on the uniformly mixed epoxy resin material. An appropriate amount of untreated fiberglass cloth of the same size is taken. The uniformly mixed epoxy resin is impregnated layer by layer in a metal mold. The mass ratio of fiberglass cloth to epoxy resin is 6:4. The fiber carrying nano SiC particles is arranged on the top layer.

[0044] After impregnation, the mold is placed between the heating plates of the flat vulcanizing machine and hot-pressed at 140℃ / 10MPa for 20 minutes to form. After demolding, the formed composite material sample is taken and continuously cured at 120℃ for 10 hours to obtain the epoxy composite material sample with fiber-supported nano-SiC structure.

[0045] Table 1. Reagent dosage for different fiber ratios carrying nanoparticle structures

[0046]

[0047] Figure 2 The microstructure characterization results of fibers with different amounts of nano-SiC prepared in Example 1 of this invention are shown. It can be observed that the untreated fiber surface is smooth with gaps of 1–2 μm between fibers; the treated fiber surface has a layer of nano-SiC particles attached, increasing the surface roughness. The SiC attachment layer can fill the gaps between fibers, and as the concentration of nanoparticles increases, the SiC attachment layer becomes increasingly dense, gradually filling the gaps on the fiber surface, and the groove-like defects originally present in the nano-SiC attachment layer gradually become complete.

[0048] Figure 3The microstructure of the fiber surface with different amounts of nano-SiC loaded in Example 1 of this invention is shown. It can be observed that the surface of the untreated composite material sample is relatively smooth, the bond between the fiber and the resin is relatively tight, and some unevenness exists in the resin matrix. A small amount of particulate matter adheres to the surface of the modified epoxy composite material. However, with the increase of nano-SiC concentration, the nanoparticle structure loaded on the fiber fills the gaps between the fibers and forms a relatively complete filler adhesion layer, thus making the surface of the composite material smoother again, and the bond between the fiber and the resin matrix becomes even tighter.

[0049] Example 2

[0050] To further verify the beneficial effects of the composite material prepared by this invention as an insulating material, this embodiment conducts DC surface flashover tests and surface charge tests on the composite material prepared in Example 1. Figure 4 , Figure 5 These are schematic diagrams of the DC surface flashover test platform and the surface charge test platform used in this embodiment.

[0051] Figure 6 The DC surface flashover test results of fiber composite material samples with different nano-SiC loading amounts prepared in Example 1 of this invention are shown in Table 2. The flashover voltage test results of 10 tests for each group of samples were processed by Weibull distribution, and the flashover voltage value under 63.2% failure probability was taken as the final result.

[0052] Table 2. Shape and dimensional parameters of the Weibull distribution of surface flashover voltage in epoxy composite materials.

[0053]

[0054]

[0055] It can be seen that the flashover voltage of epoxy composites with fiber-supported nano-SiC structures is significantly improved, and the surface flashover voltage of the composite material shows an upward trend as the nano-SiC adhesion layer on the fiber surface gradually improves. Among them, the improvement effect of modified material #3 is the most obvious, with a flashover voltage of 11.59kV, which is 36.03% higher than that of unmodified epoxy resin. This indicates that the pre-structured fiber-supported nanoparticle structure can effectively improve the surface pressure resistance of epoxy composites, and its improvement effect is very significant under appropriate process parameters.

[0056] The flashover voltage of glass fiber modified epoxy resin without filler was increased by 6.5% compared to pure epoxy; the surface flashover voltage of epoxy composite material with nano-SiC as the modified coating but without fiber support structure was increased by 22.60% compared to pure epoxy.

[0057] Figure 7 The surface charge dissipation curves of epoxy composite samples with different nano-SiC loading amounts prepared in Example 1 of this invention show that the surface charge dissipation rate of the epoxy composite material exhibits a monotonically increasing trend with increasing nano-SiC concentration. This indicates that the network structure with nanoparticles as connecting points promotes the transport of surface charge, suppresses the local charge accumulation effect, and alleviates the flashover discharge phenomenon caused by electric field distortion. It also shows that excessively high loading concentration does not monotonically increase the flashover voltage; selecting appropriate loading concentration and process parameters is necessary to obtain better modification effects.

[0058] Comparative Example 1

[0059] The surface flashover voltage data of the sample obtained in Example 1 of this invention were compared with the flashover data of the glass fiber-modified nano-SiC sample without plasma treatment. The results are shown in Table 3. Figure 8 As shown.

[0060] Table 3. Statistical results of flashover voltage Weibull distribution of modified samples without plasma treatment.

[0061]

[0062]

[0063] It can be seen that the surface flashover voltage improvement effect of the modified sample obtained by the method of the present invention is significantly better than that of the modified control group without plasma treatment; and the surface flashover voltage of the modified sample without plasma treatment tends to decrease when the amount of nano-SiC filling is high. This is closely related to the bonding degree and dispersibility between the filler and the fiber.

[0064] Since untreated glass fibers are difficult to form a stable and uniform bonding structure with nanofillers, the filler particles will agglomerate after impregnation with resin, which seriously affects the insulation performance of the composite material. However, after plasma treatment, the surface of the glass fibers is excited, making it easier for nanoparticles and resin matrix to form a stable bond, thus significantly improving the modification effect of the fiber-mounted nanoparticle structure.

[0065] This invention utilizes a method for constructing a filler network structure on the surface of glass fiber fabric using semiconductor nanoparticles, combined with plasma treatment technology to activate the fiber surface, to achieve stable and efficient preparation of a fiber-mounted nanoparticle structure. Based on this structure, the composite material obtained by impregnating epoxy resin can form a charge dissipation pathway inside with nanoparticles as connection points, significantly improving the surface charge dissipation rate of the material, thereby increasing its surface flashover voltage.

[0066] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing a composite material by loading nanoparticles onto fibers and filling epoxy resin, characterized in that: include, Nanoparticles are immersed in an aqueous epoxy resin solution, thoroughly mixed, and then coated onto pre-activated glass fibers. After drying, a fiber fabric carrying nanoparticles is obtained. Epoxy resin, curing agent and accelerator are mixed and stirred evenly. After vacuum degassing, glass fiber is impregnated layer by layer. Fiber fabric with nanoparticles is placed on the top layer, and hot-pressed and cured to obtain a composite material of fiber with nanoparticles filled with epoxy resin. The activation method of the pre-activated glass fiber includes arranging the ultrasonically cleaned and dried glass fiber below the plasma jet electrode, and activating the glass fiber by introducing argon gas into the jet tube and connecting a high-frequency high-voltage power supply to obtain a stable discharge plasma plume. The fiber fabric carrying nanoparticles, wherein the mass ratio of nanoparticles to glass fibers is 1-4:2.24; The mass ratio of the epoxy resin, curing agent, and accelerator is 80-120:60-100:1-2; The mass ratio of epoxy resin to glass fiber fabric is 3-5:5-7.

2. The method for preparing composite materials by fiber-loaded nanoparticle-filled epoxy resin as described in claim 1, characterized in that: The nanoparticles include nano-SiC, ZnO, BaTiO3, and BiFeO3.

3. The method for preparing composite materials by fiber-loaded nanoparticle-filled epoxy resin as described in claim 1, characterized in that: The epoxy resin is an electrical insulating epoxy resin, including E-51 type, E44 type bisphenol A epoxy resin, S186 type, and OSC type alicyclic epoxy resin; the curing agent is an anhydride curing agent, including methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, and maleic anhydride; the accelerator is an accelerator for epoxy-anhydride systems, including 2,4,6-tris(dimethylaminomethyl)phenol, benzylamine, and glycerol.

4. The method for preparing composite materials by fiber-loaded nanoparticle-filled epoxy resin as described in claim 1, characterized in that: The hot pressing process involves a hot pressing temperature of 80–160°C, a hot pressing pressure of 8–10 MPa, and a hot pressing time of 20–60 min.

5. The method for preparing composite materials by fiber-loaded nanoparticle-filled epoxy resin as described in claim 1, characterized in that: The curing process involves a curing temperature of 25℃ to 160℃ and a curing time of 2 to 10 hours.

6. An application of a fiber-loaded nanoparticle-filled epoxy resin composite material, characterized in that: The method for preparing a composite material by loading nanoparticles onto epoxy resin with fibers as described in any one of claims 1 to 5 further includes, Using composite materials made by loading nanoparticles onto epoxy resin to prepare insulating devices can effectively improve the dissipation rate of surface charge, thereby alleviating surface field distortion and increasing surface flashover voltage.

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