Silicone rubber composite material for insulator and preparation method thereof

Abstract

The invention discloses a silicone rubber composite material for an insulator and a preparation method of the silicone rubber composite material, and relates to the technical field of rubber materials. The silicone rubber composite material for the insulator is composed of titanium-silicon binary oxide composite carbon nanotube ceramic fiber aerogel, diatomite polypyrrole nanotube silicon dioxide coated modified filler and methyl vinyl silicone rubber. The titanium-silicon binary oxide composite carbon nanotube ceramic fiber aerogel is used as a dispersion carrier of the diatomite polypyrrole nanotube silicon dioxide coated modified filler, so that the interfacial compatibility and binding force in a silicone rubber matrix are improved, a uniform and compact network structure is formed, the molecular chain movement of the silicone rubber is effectively reduced, and the wear resistance of the silicone rubber is improved. The insulation performance is optimized, the mechanical strength and the barrier effect of the composite material are enhanced, the tensile strength and the chemical corrosion resistance are improved, the insulation performance can be stably exerted, and the service life of the composite material is prolonged.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of rubber materials, and particularly relates to a silicone rubber composite material for insulators and a preparation method thereof. BACKGROUND

[0002] With the gradual increase of voltage level, the insulation requirements of power equipment are increasingly strict and complex, and it is essential to ensure the reliable operation of power equipment, which is a core factor for ensuring the safety and stability of the power grid. The most commonly used carrier in the current power distribution and transmission field is overhead line. In recent years, the power grid has developed rapidly, resulting in an explosive increase in the number of overhead transmission lines, and the width of the corridor is expanding, which has caused deterioration of the ecological environment, intensified land use conflicts, and increased operation and maintenance costs. Therefore, the traditional cross arm cannot meet the requirements of the new power system, and the composite insulating cross arm can effectively reduce the width of the overhead line corridor and has excellent insulation performance, light weight, corrosion resistance, good economy, and high strength mechanical bearing performance. Therefore, this technology has been widely used in high-voltage transmission engineering. Silicone rubber material is widely used in the power industry for high-voltage insulating appliances and other occasions with high insulation performance requirements due to its excellent heat resistance, cold resistance, insulation, and aging resistance.

[0003] The existing technology mainly has the following problems:

[0004] The mechanical strength and chemical corrosion resistance of silicone rubber are not good enough to cope with damage caused by external pressure and chemical corrosion, which is not conducive to the stable performance of its insulation and limits the service life of the material. SUMMARY

[0005] In view of the above problems, the present application provides a silicone rubber composite material for insulators, which comprises the following components by weight: titanium-silicon binary oxide composite carbon nanotube ceramic fiber aerogel 20-30 parts, diatomite polypyrrole nanotube silica coated modified filler 50-60 parts, and methyl vinyl silicone rubber 80-100 parts.

[0006] The titanium-silicon binary oxide composite carbon nanotube ceramic fiber aerogel comprises the following components by weight: silica spinning sol 65-75 parts, and tetrabutyl titanate and multi-walled carbon nanotube dispersion liquid 25-35 parts.

[0007] The diatomite polypyrrole nanotube silica coated modified filler comprises the following components by weight: diatomite polypyrrole nanotube silica combined filler 50-60 parts, and N-(beta-aminoethyl)-gamma-aminopropyl trimethoxysilane 3-5 parts.

[0008] The preparation method of the titanium silicon binary oxide composite carbon nanotube ceramic fiber aerogel specifically comprises the following steps:

[0009] (1) 1.0-2.0 g of multi-walled carbon nanotubes are added into 40 mL of a mixed acid solution for ultrasonic treatment for 1-2 h, in the mixed acid solution, the volume ratio of 98% sulfuric acid and 68% nitric acid is 3:1, and then the solution is placed in a 60-80°C water bath for heating and refluxing for 4-6 h, and then centrifugal washing is performed until neutral, and drying is performed; after the acidification treatment of the multi-walled carbon nanotubes, carboxyl and hydroxyl functional groups are introduced onto the surface of the multi-walled carbon nanotubes, so that the multi-walled carbon nanotubes are more easily dispersed in water or an organic solvent, and can form stronger chemical bonds or hydrogen bonds with polymers, ceramics or metal oxides, so that interface defects are reduced, the mechanical strength of the composite material is improved, and pretreated multi-walled carbon nanotubes are obtained;

[0010] (2) 20.0-40.0 g tetraethyl orthosilicate, 6-12 mL water, 6-10 mL anhydrous ethanol and 0.14-0.28 g oxalic acid are stirred and mixed for 6-8 h to prepare a silica precursor sol solution, 0.5-1.0 g polyvinyl butyral is added to 10 mL anhydrous ethanol and stirred and dissolved, then mixed with the silica precursor sol solution, the stirring speed is 100-200 rpm, the stirring time is 3-4 h, a silica spinning sol is prepared and used, 25.0-45.0 g tetrabutyl titanate and 220-380 mL glacial acetic acid are stirred for 3-4 h, then the pretreated multi-walled carbon nanotubes in step (1) are added and stirred for 30-50 min to prepare a tetrabutyl titanate and multi-walled carbon nanotube dispersion solution, then the silica spinning sol and the tetrabutyl titanate and multi-walled carbon nanotube dispersion solution are stirred and mixed for 4-6 h, the obtained composite spinning solution is loaded into a syringe, a 7-gauge needle is selected as the spinning needle tube, the electrostatic pressure is 18-25 kV, the distance between the needle and the receiver is 10-20 cm, the feeding pump liquid rate is 0.3-0.7 mL / h, the receiving roller speed is 30 rpm, the nanofiber membrane is collected in a crucible and placed in a muffle furnace for calcination, the heating speed is 5 ℃ / min, the temperature is kept at 800-900 ℃ for 20-30 min, in the process of this process, titanium dioxide is first generated in situ on the surface of the multi-walled carbon nanotubes, the silica sol is then formed into a three-dimensional network through a condensation reaction, and then it is network coated, and then a continuous fiber is formed through electrospinning, high-temperature calcination optimizes the pore size distribution of the fiber membrane and eliminates active groups such as surface hydroxyl groups, and improves the high-temperature stability and chemical stability of the ceramic fiber, wherein the Ti-O-C bond formed by titanium dioxide is tightly anchored on the surface of the multi-walled carbon nanotubes, avoiding the agglomeration of the multi-walled carbon nanotubes, and also enhancing the interfacial bonding of the multi-walled carbon nanotubes and the ceramic matrix, the titanium dioxide and the silica are connected through Ti-O-Si bonds, further fixing the titanium dioxide and the multi-walled carbon nanotubes, forming a porous core-shell structure, the multi-walled carbon nanotubes can effectively inhibit the brittle fracture of the ceramic fiber, improve the tensile strength and toughness, the hydrophobicity and high aspect ratio of the multi-walled carbon nanotubes can prolong the diffusion path of the corrosion medium, and improve the chemical corrosion resistance, and a composite ceramic fiber membrane is obtained;

[0011] (3) dispersing the composite ceramic fiber membrane of step (2) in 200 mL of deionized water, ultrasonic treatment for 1-2 h, then pour into the mold, placed in liquid nitrogen bath rapid freezing, to prevent the fiber re-aggregation, then the frozen sample is put into a freeze dryer, freeze drying at-50 DEG C for 24-36 h, with silica, titanium dioxide and multi-walled carbon nanotubes as raw materials, the composite ceramic fiber membrane is further formed into aerogel, the nano-porous structure of the aerogel can not only be used as a rigid skeleton to limit the slip of the molecular chain of silicone rubber, improve the modulus and creep resistance, but also can absorb impact energy, hinder the propagation of micro-cracks, the network structure of the aerogel can hinder the penetration of corrosive medium, delay the corrosion of the silicone rubber matrix and the interface, the insulation barrier effect of the titanium dioxide and the silica ceramic fiber in the aerogel offsets the adverse effects of the increase of the interface area, blocks the formation of the continuous conductive network, and optimizes the insulation performance, wherein the chemical stability of the titanium dioxide and the silica is good, and the multi-walled carbon nanotubes can prolong the diffusion path of the corrosive medium, so that the corrosion of the acid, alkali and organic solvent and other corrosive media can be effectively resisted, and the titanium-silicon binary oxide composite carbon nanotube ceramic fiber aerogel is obtained;

[0012] Preferably, in step (1), the multi-walled carbon nanotube has a tube diameter of 5-15 nm and a length of 1-2 um, and the nanoscale tube diameter and micrometer-scale length enable it to have excellent stress transfer capacity, form a three-dimensional reinforcing skeleton in the aerogel network, and significantly improve the tensile strength.

[0013] The application further provides a preparation method of the silicone rubber composite material for insulators.

[0014] S1, 1.0-2.0 g of methyl orange is dissolved in a mixed solution of 50 mL of ethanol and 200 mL of deionized water, and 200 mL of a 1% pyrrole solution is slowly added under low temperature and light shielding at a stirring speed of 650-750 rpm, and then 80 mL of a 6.0-7.0% iron chloride hydrochloride solution is added dropwise, and the reaction is carried out for 10-12 h after the dropwise addition is completed, and the sample is left overnight, filtered, washed with water until colorless, and vacuum dried, so that the polypyrrole with a one-dimensional nanotube structure is prepared by a soft template method, the polypyrrole has excellent acid and oxidation resistance, and the stability is better than that of carbon materials, especially in an acidic or oxidizing environment, the polypyrrole nanotube has better compatibility with silicone rubber and higher efficient stress transfer, and the polypyrrole nanotube is obtained.

[0015] S2, the polypyrrole nanotube described in step S1 is dispersed in 50 mL of deionized water, after ultrasonic treatment for 1-2 h, 16.0-18.0 g of anhydrous citric acid is added, and ultrasonic treatment is continued for 3-4 h, then diatomite is added, and ultrasonic treatment is carried out for 1-2 h to obtain a polypyrrole nanotube and diatomite dispersion liquid, which is used as received, 150-200 mL of water glass and 600 mL of deionized water are mixed uniformly, heated to 70-80°C, 6.25 mL of ethanol is added dropwise, then the polypyrrole nanotube and diatomite dispersion liquid is slowly added dropwise, the pH is adjusted to 6.0, 400 mL of ethanol is added, stirred for 0.5-1 h, left to stand overnight, centrifuged, the precipitate is washed with deionized water and ethanol for 3-5 times, vacuum dried, and passed through an 80-100 mesh screen, firstly, the polypyrrole nanotube is loaded in the diatomite pore channel to form a diatomite-polypyrrole nanotube carrier, secondly, the silica generated by the hydrolysis of the water glass is deposited on the surface of the diatomite-polypyrrole nanotube carrier and forms a dense wrapping layer, the coating of silica not only forms an armor effect on the surface of the carrier to improve the mechanical strength of the filler, but also protects the structure stability of the carrier in an acid and alkali environment, and also inhibits the electrical conductivity of the polypyrrole nanotube, optimizes the insulation performance, and the templating effect of the carrier also effectively reduces the self-agglomeration phenomenon of silica, realizing the maximization of the effect of the combination use of the three fillers, wherein the natural porous surface and abundant silicon hydroxyl groups of diatomite provide physical adsorption and chemical bonding anchoring sites for silica, the addition of anhydrous citric acid in the pretreatment makes the surface of diatomite and polypyrrole nanotube negatively charged, and the interface combination with silica is enhanced by electrostatic action, further promoting the directional coating of silica, and obtaining a diatomite-polypyrrole nanotube-silica combined filler;

[0016] S3, dispersing N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane in 10 mL of 95% mass fraction ethanol solution, adding a small amount of acetic acid to adjust the pH to 4.0-5.0, magnetic stirring for 30-60 min, and the obtained modified liquid is ready for use. Then, the diatomite polypyrrole nanotube silica composite filler described in step S2 is first dried at 100-110°C under vacuum for 1-2 h to remove the surface moisture, then dispersed in 50 mL of anhydrous ethanol, ultrasonic treated for 20-30 min to form a filler suspension ready for use. Then, the modified liquid is slowly added to the filler suspension, and magnetic stirring is carried out at 60-80°C for 4-6 h, followed by ultrasonic treatment for 20-30 min, washed with ethanol and centrifuged 3-5 times, and the precipitate is vacuum dried. N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane forms an organic-inorganic hybrid layer on the surface of the composite filler, filling the micropores or defects in the composite filler, reducing the charge migration path, thereby enhancing the insulation performance. After the trimethoxy of N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane is hydrolyzed, it is condensed with other silicon hydroxyl groups to form a cross-linked network inside the filler, improving the mechanical properties such as tensile strength and wear resistance. The hydrophobic layer formed by N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane on the surface of the filler can block the penetration of corrosive media, enhancing the chemical corrosion resistance. The diatomite polypyrrole nanotube silica coated modified filler is obtained.

[0017] S4, pour methyl vinyl silicone rubber, titanium silicon binary oxide composite carbon nanotube ceramic fiber aerogel, diatomite polypyrrole nanotube silica coated modified filler in step S3 into a three-roll mill for mechanical mixing, slow roller speed 30-50 rpm, middle roller speed 100-150 rpm, fast roller speed 200-400 rpm, after uniform mixing, the mixture is heated and pressurized by a flat vulcanizing machine, vulcanization temperature 120-160℃, vulcanization time 5-10 min, vulcanization pressure 10-15 MPa, titanium silicon binary oxide composite carbon nanotube ceramic fiber aerogel is uniformly dispersed in the aerogel through physical adsorption and chemical bonding, which also improves the dispersibility of diatomite polypyrrole nanotube silica coated modified filler in methyl vinyl silicone rubber, better embedded in the three-dimensional network structure of aerogel, at the same time, the diatomite polypyrrole nanotube silica coated modified filler also further modifies the aerogel, through the active groups such as amino and silicon hydroxyl, the chemical crosslinking between aerogel and silicone rubber is enhanced, the interface bonding is significantly strengthened, the molecular chain movement of silicone rubber is reduced, the insulation performance is improved, and the aerogel and the filler can form a uniform and dense crosslinked network in the silicone rubber matrix, the mechanical properties and barrier effect of the composite material are enhanced, the tensile strength and chemical corrosion resistance are improved, wherein the flexible organic chain of the diatomite polypyrrole nanotube silica coated modified filler can fill the pores of the aerogel, effectively reduce the interface gap, improve the mechanical interlocking effect, and also improve the damage of stress concentration to the aerogel, so as to obtain a silicone rubber composite material for insulators;

[0018] Preferably, in step S2, the amount of diatomite added is 1.0-2.0g, the diatomite as an insulating component can reduce the conduction path, its porous structure can adsorb impurity ions, reduce the conductivity, reduce the risk of leakage current, the micron-sized porous structure and high specific surface area of diatomite can form physical crosslinking points with the molecular chain of silicone rubber, improve the tensile strength and tear strength, and the chemical inertness of diatomite can also block the penetration of corrosive medium and delay the aging of silicone rubber.

[0019] Preferably, in step S3, the amount of N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane added is 0.3-0.5g, the methoxy group of the silane is hydrolyzed to form silicon hydroxyl, which can form Si-O-Si covalent bond with the hydroxyl on the surface of the filler, and the dispersion and interface compatibility of the filler in the matrix are improved through modification treatment, and the amino group can react with the active groups such as carboxyl in the aerogel to form chemical bonding.

[0020] The beneficial effects obtained by the present application are as follows:

[0021] The application improves the interface compatibility and binding force in the silicone rubber matrix by taking the titanium silicon binary oxide composite carbon nanotube ceramic fiber aerogel as the dispersion carrier of diatomite polypyrrole nanotube silica coating modified filler, forms a uniform and dense network structure, effectively reduces the silicone rubber molecular chain movement, optimizes the insulation performance, enhances the mechanical strength and barrier effect of the composite material, improves the tensile strength and chemical corrosion resistance, is conducive to the stable performance of the insulation performance, and prolongs the service life of the composite material; in the titanium silicon binary oxide composite carbon nanotube ceramic fiber aerogel, titanium dioxide is generated in situ on the surface of the multi-walled carbon nanotube, and the silica sol is network coated by polycondensation reaction, and the ceramic fiber aerogel is prepared by electrospinning, high-temperature calcination and freeze-drying process; the nano-porous structure of the aerogel can not only be used as a rigid skeleton to limit the slip of the silicone rubber molecular chain, improve the modulus and anti-cracking property, but also absorb impact energy and hinder the expansion of micro-cracks; the network structure of the aerogel can hinder the penetration of corrosive medium and delay the erosion of the silicone rubber matrix and the interface; the insulation barrier effect of titanium dioxide and silica ceramic fiber inhibits the conductivity of the multi-walled carbon nanotube and blocks the formation of a continuous conductive network, thereby optimizing the insulation performance; the Ti-O-C bond formed between titanium dioxide and the surface of the multi-walled carbon nanotube avoids the agglomeration of the multi-walled carbon nanotube and enhances the interface bonding between the multi-walled carbon nanotube and the ceramic matrix; titanium dioxide and silica are connected through Ti-O-Si bond, further fixing titanium dioxide and multi-walled carbon nanotube, forming a porous core-shell structure, and the multi-walled carbon nanotube can effectively inhibit the brittle fracture of the ceramic fiber, improve the tensile strength and toughness, and the hydrophobicity and high aspect ratio of the multi-walled carbon nanotube can also prolong the diffusion path of the corrosive medium and improve the chemical corrosion resistance; in the diatomite polypyrrole nanotube silica coating modified filler, the polypyrrole nanotube is first loaded in the pore channel of diatomite to form a diatomite-polypyrrole nanotube carrier, and the silica generated by the hydrolysis of water glass is deposited on the surface of the diatomite-polypyrrole nanotube carrier to form a dense wrapping layer; the coating of silica not only forms an armor effect on the surface of the carrier to improve the mechanical strength of the filler, but also protects the structure stability of the carrier in an acid and alkali environment, and inhibits the conductivity of the polypyrrole nanotube, thereby further optimizing the insulation performance; and the template effect of the carrier also effectively reduces the self-agglomeration of silica, thereby maximizing the effect of the combined use of the three fillers; then the diatomite polypyrrole nanotube silica composite filler is modified by N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane to fill the micropores or defects in the composite filler and reduce the charge migration path, thereby enhancing the insulation performance; the trimethoxy of N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane is hydrolyzed and crosslinked with the silicon hydroxyl in the composite filler, thereby improving the mechanical properties such as tensile strength; and the hydrophobic layer formed by N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane on the surface of the composite filler can also block the penetration of corrosive medium, thereby enhancing the chemical corrosion resistance.The application discloses a silicone rubber composite material for an insulator which is made of titanium-silicon binary oxide composite carbon nanotube ceramic fiber aerogel, diatomite polypyrrole nanotube silicon dioxide coated modified filler and methyl-vinyl silicone rubber, optimizes insulation performance, enhances mechanical strength and chemical corrosion resistance, is beneficial to stable exertion of insulation performance and prolongs service life of the composite material. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 A scanning electron microscope image of a section of the silicone rubber composite material for an insulator prepared in the embodiment 1 of the application;

[0023] Figure 2 A volume resistivity result graph of the embodiment 1-4 and the comparative examples 1-3 of the application;

[0024] Figure 3 A mechanical property result graph of the embodiment 1-4 and the comparative examples 1-3 of the application;

[0025] Figure 4 A pollution resistance coefficient result graph of the embodiment 1-4 and the comparative examples 1-3 of the application. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the application will be apparently and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the application.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by one of ordinary skill in the art. In addition, any method and material similar or equivalent to those described herein can be used in the application. The preferred implementation methods and materials described herein are only used for demonstration, but cannot limit the content of the application.

[0028] The experimental methods in the following embodiments are all conventional methods unless otherwise specified. The experimental materials used in the following embodiments are all purchased from commercial channels unless otherwise specified.

[0029] Embodiment 1

[0030] The embodiment provides a silicone rubber composite material for an insulator, which comprises the following components in parts by weight: titanium-silicon binary oxide composite carbon nanotube ceramic fiber aerogel 30 parts, diatomite polypyrrole nanotube silicon dioxide coated modified filler 60 parts and methyl-vinyl silicone rubber 100 parts.

[0031] Titanium-silicon binary oxide composite carbon nanotube ceramic fiber aerogel, comprising the following components in parts by weight: 75 parts of silica spinning sol, 25 parts of tetrabutyl titanate and multi-walled carbon nanotube dispersion liquid.

[0032] Diatomite polypyrrole nanotube silica coating modified filler, comprising the following components in parts by weight: 60 parts of diatomite polypyrrole nanotube silica composite filler, 5 parts of N- (beta-aminoethyl) -gamma-aminopropyl trimethoxysilane.

[0033] Preparation method of titanium-silicon binary oxide composite carbon nanotube ceramic fiber aerogel, specifically comprising the following steps:

[0034] (1) 2.0 g of multi-walled carbon nanotubes are added to 40 mL of mixed acid solution for ultrasonic treatment for 2 h, in the mixed acid solution, the volume ratio of mass fraction 98% sulfuric acid and mass fraction 68% nitric acid is 3:1, the tube diameter of the multi-walled carbon nanotubes is 15 nm, and the length is 2 μm, the nanoscale tube diameter and micrometer scale length enable it to have excellent stress transfer capacity, to form a three-dimensional reinforcing skeleton in the aerogel network, and to significantly improve the tensile strength, and then it is placed in a 80℃ water bath for heating reflux for 6 h, centrifuged and washed to neutral, and dried, after acid treatment of the multi-walled carbon nanotubes, carboxyl and hydroxyl functional groups are introduced on the surface, which makes it more easily dispersed in water or organic solvents, and also enables it to form stronger chemical bonds or hydrogen bonds with polymers, ceramics or metal oxides, to reduce interface defects and improve the mechanical strength of the composite material, and the pretreated multi-walled carbon nanotubes are obtained;

[0035] (2) 40.0 g of tetraethyl orthosilicate, 12 mL of water, 10 mL of anhydrous ethanol and 0.28 g of oxalic acid were stirred and mixed for 8 h to prepare a silica precursor sol solution, 1.0 g of polyvinyl butyral was added to 10 mL of anhydrous ethanol and stirred and dissolved, then mixed with the silica precursor sol solution, the stirring speed was 200 rpm, and the stirring time was 4 h, to prepare a silica spinning sol solution, 45.0 g of tetrabutyl titanate and 380 mL of glacial acetic acid were stirred for 4 h, then the pretreated multi-walled carbon nanotubes in step (1) were added and stirred for 50 min to prepare a tetrabutyl titanate and multi-walled carbon nanotube dispersion solution, then the silica spinning sol solution and the tetrabutyl titanate and multi-walled carbon nanotube dispersion solution were stirred and mixed for 6 h, the obtained composite spinning solution was loaded into a syringe, a 7-gauge needle was selected as the spinning needle tube, the electrostatic pressure was 25 kV, the distance between the needle and the receiver was 20 cm, the feeding pump liquid rate was 0.7 mL / h, the receiving roller rotating speed was 30 rpm, the collected nanofiber membrane was placed in a crucible and put into a muffle furnace for calcination, the heating rate was 5 ℃ / min, and the temperature was kept at 900 ℃ for 30 min. In the process of this process, titanium dioxide is first generated in situ on the surface of the multi-walled carbon nanotube, the silica sol is then formed into a three-dimensional network through a condensation reaction, and then it is network coated, and then a continuous fiber is formed by electrospinning, and high-temperature calcination optimizes the pore size distribution of the fiber membrane and eliminates active groups such as surface hydroxyl groups, thereby improving the high-temperature stability and chemical stability of the ceramic fiber. Among them, the Ti-O-C bond formed by titanium dioxide is tightly anchored on the surface of the multi-walled carbon nanotube, avoiding the agglomeration of the multi-walled carbon nanotube, and also enhancing the interfacial bonding between the multi-walled carbon nanotube and the ceramic matrix. Titanium dioxide and silicon dioxide are connected through Ti-O-Si bonds, further fixing titanium dioxide and multi-walled carbon nanotubes, forming a porous core-shell structure. The multi-walled carbon nanotube can effectively inhibit the brittle fracture of the ceramic fiber, improve the tensile strength and toughness, the hydrophobicity and high aspect ratio of the multi-walled carbon nanotube can prolong the diffusion path of the corrosion medium, and improve the chemical corrosion resistance, and a composite ceramic fiber membrane is obtained;

[0036] (3) dispersing the composite ceramic fiber membrane of step (2) in 200 mL of deionized water, ultrasonic treatment for 2 h, then poured into the mold, placed in liquid nitrogen bath for rapid freezing, to prevent the fibers from re-aggregation, then the frozen sample is placed in a freeze dryer, freeze-dried at-50℃ for 36 h, using silica, titanium dioxide and multi-walled carbon nanotubes as raw materials, the composite ceramic fiber membrane prepared is further formed into aerogel, the nano-porous structure of the aerogel not only can be used as a rigid skeleton to restrict the slipping of the molecular chain of the silicone rubber, improve the modulus and creep resistance, but also can absorb impact energy and hinder the propagation of micro-cracks, the network structure of the aerogel can hinder the penetration of corrosive media and delay the corrosion of the silicone rubber matrix and the interface, the insulation barrier effect of titanium dioxide and silica ceramic fibers in the aerogel offsets the adverse effects of the increase of the interface area, blocks the formation of a continuous conductive network, and optimizes the insulation performance, wherein the chemical stability of titanium dioxide and silica is good, and the multi-walled carbon nanotubes can prolong the diffusion path of the corrosive medium, so as to effectively resist the corrosion of acid, alkali and organic solvent, and a titanium-silicon binary oxide composite carbon nanotube ceramic fiber aerogel is obtained.

[0037] The embodiment provides a preparation method of a silicone rubber composite material for insulators, and specifically comprises the following steps:

[0038] S1, 2.0 g of methyl orange is dissolved in a mixed solution of 50 mL of ethanol and 200 mL of deionized water, and 200 mL of a 1% pyrrole solution is slowly added under low temperature and light shielding at a stirring speed of 750 rpm, and then 80 mL of a 7.0% iron chloride hydrochloride solution is added dropwise, and the reaction is carried out for 12 h after the dropwise addition is completed, and the sample is left overnight, filtered, washed with water until colorless, and vacuum dried, a poly-pyrrole with a one-dimensional nanotube structure is prepared by a soft template method, the poly-pyrrole has excellent acid and oxidation resistance, and the stability of the poly-pyrrole is better than that of carbon materials, especially in an acidic or oxidizing environment, the compatibility of the poly-pyrrole nanotube with the silicone rubber is better, and the stress transfer is also more efficient, and a poly-pyrrole nanotube is obtained.

[0039] S2, the polypyrrole nanotube described in step S1 is dispersed in 50 mL of deionized water, after ultrasonic treatment for 2 h, 18.0 g of anhydrous citric acid is added, and ultrasonic treatment is continued for 4 h, then diatomite is added, the amount of diatomite added is 2.0 g, diatomite can reduce the conductive path as an insulating component, its porous structure can adsorb impurity ions, reduce the conductivity and reduce the risk of leakage current, the micron level porous structure and high specific surface area of diatomite can form physical crosslinking points with the molecular chain of silicone rubber, improve the tensile strength and tear strength, the chemical inertness of diatomite can also block the penetration of corrosive medium and delay the aging of silicone rubber, ultrasonic treatment for 2 h, to obtain a polypyrrole nanotube and diatomite dispersion liquid for use, then mix 200 mL of water glass and 600 mL of deionized water uniformly, heat to 80°C, drop 6.25 mL of ethanol, then slowly drop the polypyrrole nanotube and diatomite dispersion liquid, adjust the pH to 6.0, add 400 mL of ethanol, stir for 1 h, stand overnight, centrifuge, wash the precipitate with deionized water and ethanol 5 times, vacuum dry, pass through a 100 mesh screen, first, the polypyrrole nanotube is loaded in the diatomite pore, forming a diatomite-polypyrrole nanotube carrier, second, the silica generated by the hydrolysis of water glass is deposited on the surface of the diatomite-polypyrrole nanotube carrier and forms a dense wrapping layer, the coating of silica not only forms an armor effect on the surface of the carrier, improving the mechanical strength of the filler, but also protects the structural stability of the carrier in an acidic or alkaline environment, and also inhibits the electrical conductivity of the polypyrrole nanotube, optimizing the insulation performance, and the template effect of the carrier also effectively reduces the self-agglomeration phenomenon of silica, realizing the maximization of the effect of the combination of the three fillers, among them, the natural porous surface of diatomite and the abundant silicon hydroxyl groups provide physical adsorption and chemical bonding anchor points for silica, the addition of anhydrous citric acid in the pretreatment makes the surface of diatomite and polypyrrole nanotube negatively charged, and the silica is combined through electrostatic interaction to further promote the directional coating of silica, to obtain a diatomite-polypyrrole nanotube-silica combined filler;

[0040] S3, dispersing N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane in 10 mL of 95% mass fraction ethanol solution, the amount of N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane added is 0.5 g, the methoxy group of the silane is hydrolyzed to form silicon hydroxyl group, which can form Si-O-Sil covalent bond with the hydroxyl group on the surface of the filler to modify the filler and enhance the dispersibility and interfacial compatibility of the filler in the matrix, and the amino group can react with the active groups such as carboxyl group in the aerogel to form chemical bonding, a small amount of acetic acid is added to adjust the pH to 5.0, and magnetic stirring is performed for 60 min, the obtained modified liquid is used, and then the diatomite polypyrrole nanotube silica composite filler described in step S2 is vacuum dried at 110°C for 2 h to remove the water on the surface, and then dispersed in 50 mL of anhydrous ethanol, ultrasonic treatment is performed for 30 min to form a filler suspension for use, then the modified liquid is slowly added to the filler suspension, magnetic stirring is performed at 80°C for 6 h, followed by ultrasonic treatment for 30 min, washed with ethanol and centrifuged 5 times, the precipitate is vacuum dried, the N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane forms an organic-inorganic hybrid layer on the surface of the composite filler, fills the micropores or defects in the composite filler, reduces the charge migration path, and thus enhances the insulation performance, the trimethoxy group of the N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane is hydrolyzed to form a cross-linked network with other silicon hydroxyl groups in the filler, which improves the mechanical properties such as tensile strength and wear resistance, the hydrophobic layer formed by the N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane on the surface of the filler can block the penetration of corrosive medium, and thus enhances the chemical corrosion resistance, and a diatomite polypyrrole nanotube silica coated modified filler is obtained;

[0041] S4, the methyl vinyl silicone rubber, titanium silicon binary oxide composite carbon nanotube ceramic fiber aerogel, diatomite polypyrrole nanotube silica coated modified filler described in step S3 is poured into a three-roll mill for mechanical mixing, the slow roller speed is 50 rpm, the middle roller speed is 150 rpm, and the fast roller speed is 400 rpm; after uniform mixing, the mixture is heated and pressurized by a flat vulcanizing machine to form a vulcanized product, the vulcanization temperature is 160°C, the vulcanization time is 10 min, and the vulcanization pressure is 15 MPa; the titanium silicon binary oxide composite carbon nanotube ceramic fiber aerogel is uniformly dispersed in the aerogel through physical adsorption and chemical bonding, which improves the dispersibility of the diatomite polypyrrole nanotube silica coated modified filler in the methyl vinyl silicone rubber, and better embeds the three-dimensional network structure of the aerogel; at the same time, the diatomite polypyrrole nanotube silica coated modified filler further modifies the aerogel, and the active groups such as amino and silicon hydroxyl groups enhance the chemical cross-linking between the aerogel and the silicone rubber, significantly strengthens the interface bonding, reduces the movement of the silicone rubber molecular chain, improves the insulation performance, and the aerogel and the filler can form a uniform and dense cross-linked network in the silicone rubber matrix, which enhances the mechanical properties and barrier effect of the composite material, improves the tensile strength and chemical corrosion resistance, wherein the flexible organic chain of the diatomite polypyrrole nanotube silica coated modified filler can fill the pores of the aerogel, effectively reduce the interface gap, improve the mechanical interlocking effect, and also improve the damage of stress concentration to the aerogel, thereby obtaining a silicone rubber composite material for insulators.

[0042] In this embodiment, the cross section of the prepared silicone rubber composite material for insulators is observed by scanning electron microscopy, and the micro-morphology is observed, Figure 1 The SEM image of the cross section of the silicone rubber composite material for insulators prepared in Example 1 is magnified 100 times, as shown in Figure 1 The cross section of the silicone rubber composite material for insulators prepared in this embodiment is uniform and dense, and has good interface compatibility.

[0043] Example 2

[0044] The present embodiment provides a silicone rubber composite material for insulators, which comprises the following components by weight: titanium silicon binary oxide composite carbon nanotube ceramic fiber aerogel 20 parts, diatomite polypyrrole nanotube silica coated modified filler 50 parts, and methyl vinyl silicone rubber 80 parts.

[0045] The titanium silicon binary oxide composite carbon nanotube ceramic fiber aerogel comprises the following components by weight: silica spinning sol 65 parts, and titanium tetrabutoxide and multi-walled carbon nanotube dispersion liquid 35 parts.

[0046] The diatomite polypyrrole nanotube silica-coated modified filler comprises the following components in parts by weight: diatomite polypyrrole nanotube silica combined filler 50 parts, N-(beta-aminoethyl)-gamma-aminopropyl trimethoxysilane 3 parts.

[0047] The application discloses a preparation method of a titanium-silicon binary oxide composite carbon nanotube ceramic fiber aerogel.

[0048] (1) 1.0 g of multi-walled carbon nanotubes is added into 40 mL of a mixed acid solution for ultrasonic treatment for 1 h, the volume ratio of 98% sulfuric acid and 68% nitric acid in the mixed acid solution is 3:1, the tube diameter of the multi-walled carbon nanotubes is 5 nm, and the length is 1 mu m; the nanoscale tube diameter and the microscale length enable the multi-walled carbon nanotubes to have excellent stress transfer capacity, to form a three-dimensional reinforcing skeleton in the aerogel network, and to significantly improve the tensile strength; the multi-walled carbon nanotubes are placed in a 60 DEG C water bath for heating and refluxing for 4 h, centrifugal washing is performed until neutral, and drying is performed; after the multi-walled carbon nanotubes are subjected to acidification treatment, carboxyl and hydroxyl functional groups are introduced onto the surface of the multi-walled carbon nanotubes, the multi-walled carbon nanotubes are more easily dispersed in water or an organic solvent, the multi-walled carbon nanotubes can form stronger chemical bonds or hydrogen bonds with polymers, ceramics or metal oxides, interface defects are reduced, the mechanical strength of a composite material is improved, and pretreated multi-walled carbon nanotubes are obtained;

[0049] (2) 20.0 g of tetraethyl orthosilicate, 6 mL of water, 6 mL of anhydrous ethanol and 0.14 g of oxalic acid were stirred and mixed for 6 h to prepare a silica precursor sol solution, 0.5 g of polyvinyl butyral was added to 10 mL of anhydrous ethanol and stirred and dissolved, then mixed with the silica precursor sol solution, the stirring speed was 100 rpm, and the stirring time was 3 h, to prepare a silica spinning sol solution, 25.0 g of tetrabutyl titanate and 220 mL of glacial acetic acid were stirred for 3 h, then the pretreated multi-walled carbon nanotubes in step (1) were added and stirred for 30 min to prepare a tetrabutyl titanate and multi-walled carbon nanotube dispersion solution, then the silica spinning sol solution and the tetrabutyl titanate and multi-walled carbon nanotube dispersion solution were stirred and mixed for 4 h, the obtained composite spinning solution was loaded into a syringe, a 7-gauge needle was selected as the spinning needle tube, the electrostatic pressure was 18 kV, the distance between the needle and the receiver was 10 cm, the feeding pump liquid rate was 0.3 mL / h, the receiving roller rotating speed was 30 rpm, and the collected nanofiber membrane was placed in a crucible and put into a muffle furnace for calcination, the heating rate was 5 ℃ / min, and the temperature was kept at 800 ℃ for 20 min. In the process of this process, titanium dioxide is first generated in situ on the surface of the multi-walled carbon nanotube, the silica sol is then formed into a three-dimensional network through a condensation reaction, and then it is network coated, and then a continuous fiber is formed by electrospinning, and high-temperature calcination optimizes the pore size distribution of the fiber membrane and eliminates active groups such as surface hydroxyl groups, thereby improving the high-temperature stability and chemical stability of the ceramic fiber. Among them, the Ti-O-C bond formed by titanium dioxide is tightly anchored on the surface of the multi-walled carbon nanotube, avoiding the agglomeration of the multi-walled carbon nanotube, and also enhancing the interfacial bonding between the multi-walled carbon nanotube and the ceramic matrix. Titanium dioxide and silicon dioxide are connected through Ti-O-Si bonds, further fixing titanium dioxide and multi-walled carbon nanotubes, forming a porous core-shell structure, multi-walled carbon nanotubes can effectively inhibit the brittle fracture of ceramic fibers, improve the tensile strength and toughness, the hydrophobicity and high aspect ratio of multi-walled carbon nanotubes can prolong the diffusion path of the corrosion medium, and improve the chemical corrosion resistance, and a composite ceramic fiber membrane is obtained;

[0050] (3) dispersing the composite ceramic fiber membrane of step (2) in 200 mL of deionized water, ultrasonic treatment for 1 h, then poured into the mold, placed in liquid nitrogen bath for rapid freezing, to prevent the fibers from re-aggregation, then the frozen sample is placed in a freeze dryer, freeze-dried at-50℃ for 24 h, with silica, titanium dioxide and multi-walled carbon nanotubes as raw materials, the composite ceramic fiber membrane prepared is further formed into aerogel, the nano-porous structure of the aerogel not only can be used as a rigid skeleton to restrict the slip of the molecular chain of the silicone rubber, improve the modulus and creep resistance, but also can absorb impact energy and hinder the propagation of micro-cracks, the network structure of the aerogel can hinder the penetration of corrosive media and delay the corrosion of the silicone rubber matrix and the interface, the insulation barrier effect of titanium dioxide and silica ceramic fibers in the aerogel offsets the adverse effects of the increase of the interface area, blocks the formation of continuous conductive network, and optimizes the insulation performance, wherein the chemical stability of titanium dioxide and silica is good, and the multi-walled carbon nanotubes can prolong the diffusion path of the corrosive medium, so as to effectively resist the corrosion of acid, alkali, organic solvent and other corrosive media, and a titanium-silicon binary oxide composite carbon nanotube ceramic fiber aerogel is obtained.

[0051] The embodiment provides a preparation method of a silicone rubber composite material for insulators, and specifically comprises the following steps:

[0052] S1, 1.0 g of methyl orange is dissolved in a mixed solution of 50 mL of ethanol and 200 mL of deionized water, and 200 mL of a 1% by mass pyrrole solution is slowly added under low temperature and light shielding at a stirring speed of 650 rpm, and then 80 mL of a 6.0% by mass ferric chloride hydrochloride solution is added dropwise, and the reaction is performed for 10 h after the dropwise addition is completed, and the sample is left overnight, filtered, washed with water until colorless, and vacuum dried, and a poly-pyrrole with a one-dimensional nanotube structure is prepared by a soft template method, the poly-pyrrole has excellent acid and oxidation resistance, and the stability of the poly-pyrrole is better than that of carbon materials, especially in an acidic or oxidizing environment, the poly-pyrrole nanotube has better compatibility with silicone rubber and more efficient stress transmission, and a poly-pyrrole nanotube is obtained.

[0053] S2, the polypyrrole nanotube described in step S1 is dispersed in 50 mL of deionized water, after ultrasonic treatment for 1 h, 16.0 g of anhydrous citric acid is added, and ultrasonic treatment is continued for 3 h, then diatomite is added, the amount of diatomite added is 1.0 g, diatomite can reduce the conductive path as an insulating component, its porous structure can adsorb impurity ions, reduce the conductivity and reduce the risk of leakage current, the micron level porous structure and high specific surface area of diatomite can form physical crosslinking points with the molecular chain of silicone rubber, improve the tensile strength and tear strength, the chemical inertness of diatomite can also block the penetration of corrosive medium and delay the aging of silicone rubber, ultrasonic treatment for 1 h, to obtain a polypyrrole nanotube and diatomite dispersion liquid for use, then mix 150 mL of water glass and 600 mL of deionized water uniformly, heat to 70°C, add 6.25 mL of ethanol, then slowly add the polypyrrole nanotube and diatomite dispersion liquid, adjust the pH to 6.0, add 400 mL of ethanol, stir for 0.5 h, stand overnight, centrifuge, wash the precipitate with deionized water and ethanol 3 times, vacuum dry, and pass through an 80-mesh screen. First, the polypyrrole nanotube is loaded in the diatomite pore to form a diatomite-polypyrrole nanotube carrier, second, the silica generated by the hydrolysis of water glass is deposited on the surface of the diatomite-polypyrrole nanotube carrier and forms a dense wrapping layer, the coating of silica not only forms an armor effect on the surface of the carrier to improve the mechanical strength of the filler, but also protects the structure stability of the carrier in an acid-base environment, and also inhibits the electrical conductivity of the polypyrrole nanotube, optimizes the insulation performance, and the template effect of the carrier also effectively reduces the self-agglomeration phenomenon of silica, realizing the maximization of the effect of the combination of the three fillers, wherein the natural porous surface and abundant silicon hydroxyl groups of diatomite provide physical adsorption and chemical bonding anchor points for silica, the addition of anhydrous citric acid in the pretreatment makes the surface of diatomite and polypyrrole nanotube negatively charged, and the interface bonding is enhanced by electrostatic interaction with silica, further promoting the directional coating of silica, to obtain a diatomite-polypyrrole nanotube-silica combined filler;

[0054] S3, dispersing N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane in 10 mL of 95% mass fraction ethanol solution, the amount of N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane added is 0.3 g, the methoxy group of the silane is hydrolyzed to form silicon hydroxyl group, which can form Si-O-Sil covalent bond with the hydroxyl group on the surface of the filler to modify the filler and enhance the dispersibility and interfacial compatibility of the filler in the matrix, and the amino group can react with the active groups such as carboxyl group in the aerogel to form chemical bonding, a small amount of acetic acid is added to adjust the pH to 4.0, and magnetic stirring is performed for 30 min, the obtained modified liquid is used, and then the diatomite polypyrrole nanotube silica composite filler described in step S2 is vacuum dried at 100℃ for 1 h to remove the water on the surface, and then dispersed in 50 mL of anhydrous ethanol, ultrasonic treatment is performed for 20 min to form a filler suspension for use, then the modified liquid is slowly added to the filler suspension, magnetic stirring is performed at 60℃ for 4 h, followed by ultrasonic treatment for 20 min, washed with ethanol and centrifuged 3 times, the precipitate is vacuum dried, the N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane forms an organic-inorganic hybrid layer on the surface of the composite filler, fills the micropores or defects in the composite filler, reduces the charge migration path, and thus enhances the insulation performance, the trimethoxy group of the N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane is hydrolyzed to form a cross-linked network with other silicon hydroxyl groups in the filler, which improves the mechanical properties such as tensile strength and wear resistance, the hydrophobic layer formed by the N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane on the surface of the filler can block the penetration of corrosive medium, and thus enhances the chemical corrosion resistance, and a diatomite polypyrrole nanotube silica coated modified filler is obtained;

[0055] S4, the methyl vinyl silicone rubber, titanium silicon binary oxide composite carbon nanotube ceramic fiber aerogel, diatomite polypyrrole nanotube silica coated modified filler described in step S3 is poured into a three-roll mill for mechanical mixing, the slow roller speed is 30 rpm, the middle roller speed is 100 rpm, and the fast roller speed is 200 rpm; after uniform mixing, the mixture is heated and pressurized by a flat vulcanizing machine to form a vulcanized product, the vulcanization temperature is 120°C, the vulcanization time is 5 min, and the vulcanization pressure is 10 MPa; the titanium silicon binary oxide composite carbon nanotube ceramic fiber aerogel is uniformly dispersed in the aerogel through physical adsorption and chemical bonding, which improves the dispersibility of the diatomite polypyrrole nanotube silica coated modified filler in the methyl vinyl silicone rubber, and better embeds the three-dimensional network structure of the aerogel; at the same time, the diatomite polypyrrole nanotube silica coated modified filler further modifies the aerogel, and the active groups such as amino and silicon hydroxyl groups enhance the chemical cross-linking between the aerogel and the silicone rubber, significantly strengthens the interface bonding, reduces the movement of the silicone rubber molecular chain, improves the insulation performance, and the aerogel and the filler can form a uniform and dense cross-linked network in the silicone rubber matrix, which enhances the mechanical properties and barrier effect of the composite material, improves the tensile strength and chemical corrosion resistance, wherein the flexible organic chain of the diatomite polypyrrole nanotube silica coated modified filler can fill the pores of the aerogel, effectively reduce the interface gap, improve the mechanical interlocking effect, and also improve the damage of stress concentration to the aerogel, thereby obtaining a silicone rubber composite material for insulators.

[0056] Example 3

[0057] The present embodiment provides a silicone rubber composite material for insulators, which comprises the following components by weight: titanium silicon binary oxide composite carbon nanotube ceramic fiber aerogel 25 parts, diatomite polypyrrole nanotube silica coated modified filler 55 parts, and methyl vinyl silicone rubber 90 parts.

[0058] The titanium silicon binary oxide composite carbon nanotube ceramic fiber aerogel comprises the following components by weight: silica spinning sol 70 parts, and tetrabutyl titanate and multi-walled carbon nanotube dispersion liquid 30 parts.

[0059] The diatomite polypyrrole nanotube silica coated modified filler comprises the following components by weight: diatomite polypyrrole nanotube silica combined filler 55 parts, and N- (β-aminoethyl) -γ-aminopropyl trimethoxysilane 4 parts.

[0060] The preparation method of the titanium silicon binary oxide composite carbon nanotube ceramic fiber aerogel comprises the following steps:

[0061] (1) 1.5 g of multi-walled carbon nanotubes is added to 40 mL of mixed acid solution for ultrasonic treatment for 1.5 h. In the mixed acid solution, the volume ratio of 98% sulfuric acid and 68% nitric acid is 3:1. The multi-walled carbon nanotubes have a tube diameter of 10 nm and a length of 1.5 μm. The nanoscale tube diameter and micrometer-scale length enable excellent stress transfer capacity, forming a three-dimensional reinforcing skeleton in the aerogel network and significantly improving the tensile strength. The multi-walled carbon nanotubes are then placed in a 70°C water bath for heating and refluxing for 5 h, centrifugally washed to neutral, and dried. After acid treatment, the multi-walled carbon nanotubes have carboxyl and hydroxyl functional groups introduced onto the surface, making them more easily dispersed in water or organic solvents and enabling stronger chemical bonds or hydrogen bonds with polymers, ceramics, or metal oxides, reducing interface defects and improving the mechanical strength of the composite material. The resulting multi-walled carbon nanotubes are pretreated;

[0062] (2) 30.0 g of tetraethyl orthosilicate, 9 mL of water, 8 mL of anhydrous ethanol, and 0.21 g of oxalic acid are stirred and mixed for 7 h to prepare a silica precursor sol solution for later use. 0.75 g of polyvinyl butyral is added to 10 mL of anhydrous ethanol and stirred and dissolved, and then mixed with the silica precursor sol solution. The stirring speed is 150 rpm, and the stirring time is 3.5 h to prepare a silica spinning sol for later use. 35.0 g of tetrabutyl titanate and 300 mL of glacial acetic acid are stirred for 3.5 h, and then the pretreated multi-walled carbon nanotubes prepared in step (1) are added and stirred for 40 min to prepare a tetrabutyl titanate and multi-walled carbon nanotube dispersion solution for later use. The silica spinning sol and the tetrabutyl titanate and multi-walled carbon nanotube dispersion solution are then stirred and mixed for 5 h. The resulting composite spinning solution is loaded into a syringe, a 7-gauge needle is selected as the spinning needle tube, the electrostatic voltage is 21.5 kV, the distance between the needle and the receiver is 15 cm, the feeding pump liquid rate is 0.5 mL / h, the receiving roller speed is 30 rpm, and the collected nanofiber membrane is placed in a crucible and placed in a muffle furnace for calcination. The temperature is raised at a rate of 5°C / min, and the temperature is maintained at 850°C for 25 min. In the process, titanium dioxide is first generated in situ on the surface of the multi-walled carbon nanotubes, the silica sol then forms a three-dimensional network through a condensation reaction, and the network is coated. The continuous fibers are then formed by electrospinning, and high-temperature calcination optimizes the pore size distribution of the fiber membrane and eliminates active groups such as surface hydroxyl groups, improving the high-temperature stability and chemical stability of the ceramic fiber. The Ti-O-C bond formed by the titanium dioxide is tightly anchored on the surface of the multi-walled carbon nanotubes, preventing the agglomeration of the multi-walled carbon nanotubes and enhancing the interface bonding between the multi-walled carbon nanotubes and the ceramic matrix. The titanium dioxide and the silica are connected by Ti-O-Si bonds, further fixing the titanium dioxide and the multi-walled carbon nanotubes, and forming a porous core-shell structure. The multi-walled carbon nanotubes can effectively inhibit the brittle fracture of the ceramic fiber, improving the tensile strength and toughness. The hydrophobicity and high aspect ratio of the multi-walled carbon nanotubes can prolong the diffusion path of the corrosion medium, improving the chemical corrosion resistance, and the resulting composite ceramic fiber membrane is obtained.

[0063] (3) The composite ceramic fiber membrane of step (2) is dispersed in 200 mL of deionized water, ultrasonic treatment for 1.5 h, then poured into a mold, placed in a liquid nitrogen bath to freeze quickly to prevent the fibers from re-aggregating, then the frozen sample is placed in a freeze dryer and freeze-dried at-50°C for 30 h, and the composite ceramic fiber membrane prepared from silica, titanium dioxide and multi-walled carbon nanotubes is further formed into an aerogel. The nano-porous structure of the aerogel not only restricts the slippage of the molecular chains of the silicone rubber, improves the modulus and creep resistance, but also absorbs impact energy and hinders the propagation of micro-cracks. The network structure of the aerogel can hinder the penetration of corrosive media and delay the corrosion of the silicone rubber matrix and the interface. The insulating barrier effect of titanium dioxide and silica ceramic fibers in the aerogel offsets the adverse effects of the increase in the interface area, blocks the formation of a continuous conductive network, and optimizes the insulation performance. The chemical stability of titanium dioxide and silica is good, and the multi-walled carbon nanotubes can extend the diffusion path of the corrosive medium, so they can effectively resist the corrosion of acid, alkali and organic solvents. A titanium-silicon binary oxide composite carbon nanotube ceramic fiber aerogel is obtained.

[0064] The embodiment provides a preparation method of a silicone rubber composite material for insulators, and specifically comprises the following steps:

[0065] S1, 1.5 g of methyl orange is dissolved in a mixed solution of 50 mL of ethanol and 200 mL of deionized water, and 200 mL of a 1% by mass pyrrole solution is slowly added under low temperature and light shielding at a stirring speed of 700 rpm, and then 80 mL of a 6.5% by mass ferric chloride hydrochloride solution is added dropwise. After the dropwise addition is completed, the reaction is carried out for 11 h, and then the sample is left overnight, filtered, washed with water until it is colorless, and vacuum dried. A poly-pyrrole with a one-dimensional nanotube structure is prepared by a soft template method. The poly-pyrrole has excellent acid and oxidation resistance, and its stability is better than that of carbon materials, especially in an acidic or oxidizing environment. The poly-pyrrole nanotube has better compatibility with silicone rubber and more efficient stress transfer, and a poly-pyrrole nanotube is obtained.

[0066] S2, the polypyrrole nanotube described in step S1 is dispersed in 50 mL of deionized water, after ultrasonic treatment for 1.5 h, 17.0 g of anhydrous citric acid is added, and ultrasonic treatment is continued for 3.5 h, then diatomite is added, the amount of diatomite added is 1.5 g, diatomite can reduce the conductive path as an insulating component, its porous structure can adsorb impurity ions, reduce the conductivity and reduce the risk of leakage current, the micron-level porous structure and high specific surface area of diatomite can form physical cross-linking points with the molecular chains of silicone rubber, improve the tensile strength and tear strength, the chemical inertness of diatomite can also block the penetration of corrosive media and delay the aging of silicone rubber, ultrasonic treatment for 1-2 h, to obtain a polypyrrole nanotube and diatomite dispersion liquid for use, then 175 mL of water glass and 600 mL of deionized water are mixed uniformly, heated to 75°C, 6.25 mL of ethanol is added, then the polypyrrole nanotube and diatomite dispersion liquid is slowly added, the pH is adjusted to 6.0, 400 mL of ethanol is added, stirred for 0.75 h, and left overnight, centrifuged, the precipitate is washed with deionized water and ethanol 4 times, vacuum dried, and passed through a 90-mesh screen. First, the polypyrrole nanotube is loaded in the diatomite pores to form a diatomite-polypyrrole nanotube carrier, second, the silica generated by the hydrolysis of water glass is deposited on the surface of the diatomite-polypyrrole nanotube carrier and forms a dense wrapping layer, the coating of silica not only forms an armor effect on the surface of the carrier to improve the mechanical strength of the filler, but also protects the structure stability of the carrier in an acidic or alkaline environment, and also inhibits the electrical conductivity of the polypyrrole nanotube, optimizes the insulation performance, and the template effect of the carrier also effectively reduces the self-agglomeration phenomenon of silica, realizing the maximization of the effect of the combination of the three fillers, wherein the natural porous surface of diatomite and the abundant silicon hydroxyl groups provide physical adsorption and chemical bonding anchor points for silica, the addition of anhydrous citric acid in the pretreatment makes the surface of diatomite and polypyrrole nanotube negatively charged, and the interface bonding is enhanced by electrostatic interaction with silica, further promoting the directional coating of silica, to obtain a diatomite-polypyrrole nanotube-silica combined filler;

[0067] S3, dispersing N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane in 10 mL of 95% mass fraction ethanol solution, the amount of N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane added is 0.4 g, the methoxy group of the silane is hydrolyzed to form silicon hydroxyl group, which can form Si-O-Sil covalent bond with the hydroxyl group on the surface of the filler to modify the filler and enhance the dispersibility and interfacial compatibility of the filler in the matrix, and the amino group can react with the active groups such as carboxyl group in the aerogel to form chemical bonding, a small amount of acetic acid is added to adjust the pH to 4.5, and magnetic stirring is performed for 45 min, the obtained modified liquid is used, and then the diatomite polypyrrole nanotube silica composite filler described in step S2 is vacuum dried at 105℃ for 1.5 h to remove the water on the surface, and then dispersed in 50 mL of anhydrous ethanol, ultrasonic treatment is performed for 25 min to form a filler suspension for use, then the modified liquid is slowly added to the filler suspension, magnetic stirring is performed at 70℃ for 5 h, followed by ultrasonic treatment for 25 min, washed with ethanol and centrifuged 4 times, the precipitate is vacuum dried, the N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane forms an organic-inorganic hybrid layer on the surface of the composite filler, fills the micropores or defects in the composite filler, reduces the charge migration path, and thus enhances the insulation performance, the trimethoxy group of the N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane is hydrolyzed to form a cross-linked network with other silicon hydroxyl groups in the filler, which improves the mechanical properties such as tensile strength and wear resistance, the hydrophobic layer formed by the N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane on the surface of the filler can block the penetration of corrosive medium, and thus enhances the chemical corrosion resistance, and a diatomite polypyrrole nanotube silica coated modified filler is obtained;

[0068] S4, the methyl vinyl silicone rubber, titanium silicon binary oxide composite carbon nanotube ceramic fiber aerogel, diatomite polypyrrole nanotube silica coated modified filler described in step S3 is poured into a three-roll mill for mechanical mixing, the slow roller speed is 40 rpm, the middle roller speed is 125 rpm, and the fast roller speed is 300 rpm. After uniform mixing, the mixture is heated and pressurized by a flat vulcanizing machine to form a vulcanized product, the vulcanization temperature is 140℃, the vulcanization time is 7.5 min, and the vulcanization pressure is 12.5 MPa. The titanium silicon binary oxide composite carbon nanotube ceramic fiber aerogel is uniformly dispersed in the aerogel through physical adsorption and chemical bonding, which improves the dispersibility of the diatomite polypyrrole nanotube silica coated modified filler in the methyl vinyl silicone rubber, and better embeds the three-dimensional network structure of the aerogel. At the same time, the diatomite polypyrrole nanotube silica coated modified filler further modifies the aerogel, and the active groups such as amino and silicon hydroxyl groups enhance the chemical crosslinking between the aerogel and the silicone rubber, significantly strengthens the interface bonding, reduces the movement of the silicone rubber molecular chain, improves the insulation performance, and the aerogel and the filler can form a uniform and dense crosslinked network in the silicone rubber matrix, which enhances the mechanical properties and barrier effect of the composite material, improves the tensile strength and chemical corrosion resistance. Among them, the flexible organic chain of the diatomite polypyrrole nanotube silica coated modified filler can fill the pores of the aerogel, effectively reduce the interface gap, improve the mechanical interlocking effect, and also improve the damage of stress concentration to the aerogel, so as to obtain a silicone rubber composite material for insulators.

[0069] Example 4

[0070] The present embodiment provides a silicone rubber composite material for insulators, which comprises the following components by weight: titanium silicon binary oxide composite carbon nanotube ceramic fiber aerogel 20 parts, diatomite polypyrrole nanotube silica coated modified filler 60 parts, and methyl vinyl silicone rubber 100 parts.

[0071] The titanium silicon binary oxide composite carbon nanotube ceramic fiber aerogel comprises the following components by weight: silica spinning sol 75 parts, and tetrabutyl titanate and multi-walled carbon nanotube dispersion liquid 25 parts.

[0072] The diatomite polypyrrole nanotube silica coated modified filler comprises the following components by weight: diatomite polypyrrole nanotube silica combined filler 60 parts, and N- (β-aminoethyl) -γ-aminopropyl trimethoxysilane 3 parts.

[0073] The preparation method of the titanium silicon binary oxide composite carbon nanotube ceramic fiber aerogel specifically comprises the following steps:

[0074] (1) 2.0 g of multi-walled carbon nanotubes were added to 40 mL of a mixed acid solution and ultrasonically treated for 1 h. In the mixed acid solution, the volume ratio of 98% sulfuric acid and 68% nitric acid was 3:1. The multi-walled carbon nanotubes had a tube diameter of 15 nm and a length of 2 μm. The nanoscale tube diameter and micrometer-scale length provided excellent stress transfer capability, and the multi-walled carbon nanotubes could form a three-dimensional reinforcing skeleton in the aerogel network, significantly improving the tensile strength. The mixture was then placed in a water bath at 80°C and heated to reflux for 4 h. After centrifugal washing until neutral, drying was performed. After acid treatment, the multi-walled carbon nanotubes had carboxyl and hydroxyl functional groups introduced onto the surface, which made them more easily dispersed in water or organic solvents. The multi-walled carbon nanotubes could also form stronger chemical bonds or hydrogen bonds with polymers, ceramics, or metal oxides, reducing interface defects and improving the mechanical strength of the composite material. The multi-walled carbon nanotubes were pretreated to obtain the pretreated multi-walled carbon nanotubes;

[0075] (2) 40.0 g of tetraethyl orthosilicate, 12 mL of water, 10 mL of anhydrous ethanol, and 0.28 g of oxalic acid were stirred and mixed for 6 h to prepare a silica precursor sol solution for later use. 1.0 g of polyvinyl butyral was added to 10 mL of anhydrous ethanol and stirred and dissolved. The solution was then mixed with the silica precursor sol solution. The stirring speed was 200 rpm, and the stirring time was 3 h. A silica spinning sol was prepared for later use. 25.0 g of tetrabutyl titanate and 380 mL of glacial acetic acid were stirred for 3 h. The pretreated multi-walled carbon nanotubes prepared in step (1) were then added, and the mixture was stirred for 30 min to prepare a tetrabutyl titanate and multi-walled carbon nanotube dispersion solution for later use. The silica spinning sol and the tetrabutyl titanate and multi-walled carbon nanotube dispersion solution were then stirred and mixed for 4 h. The resulting composite spinning solution was loaded into a syringe. A 7-gauge needle was selected as the spinning needle tube. The electrostatic voltage was 25 kV. The distance between the needle and the receiver was 10 cm. The feed rate of the advancing pump was 0.7 mL / h. The rotation speed of the receiving drum was 30 rpm. The collected nanofiber membrane was placed in a crucible and calcined in a muffle furnace. The temperature was raised at a rate of 5°C / min, and the temperature was maintained at 900°C for 20 min. In the process, titanium dioxide was first generated in situ on the surface of the multi-walled carbon nanotubes. The silica sol then formed a three-dimensional network through a condensation reaction. The network was coated, and then continuous fibers were formed by electrospinning. High-temperature calcination optimized the pore size distribution of the fiber membrane and eliminated active groups such as surface hydroxyl groups, improving the high-temperature stability and chemical stability of the ceramic fiber. The Ti-O-C bond formed by the titanium dioxide was tightly anchored to the surface of the multi-walled carbon nanotubes, preventing the agglomeration of the multi-walled carbon nanotubes and enhancing the interface bonding between the multi-walled carbon nanotubes and the ceramic matrix. The titanium dioxide and the silica were connected by Ti-O-Si bonds, further fixing the titanium dioxide and the multi-walled carbon nanotubes and forming a porous core-shell structure. The multi-walled carbon nanotubes could effectively inhibit the brittle fracture of the ceramic fiber, improving the tensile strength and toughness. The hydrophobicity and high aspect ratio of the multi-walled carbon nanotubes could prolong the diffusion path of the corrosion medium, improving the chemical corrosion resistance. A composite ceramic fiber membrane was obtained.

[0076] (3) The composite ceramic fiber membrane of step (2) is dispersed in 200 mL of deionized water, ultrasonic treatment for 1 h, then poured into a mold, placed in a liquid nitrogen bath to freeze quickly to prevent the fibers from re-aggregating, then the frozen sample is placed in a freeze dryer and freeze-dried at -50°C for 24 h, and the composite ceramic fiber membrane prepared from silica, titanium dioxide and multi-walled carbon nanotubes is further formed into an aerogel. The nano-porous structure of the aerogel not only restricts the slippage of the molecular chains of the silicone rubber, improves the modulus and creep resistance, but also absorbs impact energy and hinders the propagation of micro-cracks. The network structure of the aerogel can hinder the penetration of corrosive media and delay the corrosion of the silicone rubber matrix and the interface. The insulating barrier effect of the titanium dioxide and silica ceramic fibers in the aerogel offsets the adverse effects of the increase in the interface area, blocks the formation of a continuous conductive network, and optimizes the insulation performance. The chemical stability of titanium dioxide and silica is good, and the multi-walled carbon nanotubes can extend the diffusion path of the corrosive medium, so they can effectively resist the corrosion of acid, alkali, organic solvents and other corrosive media. A titanium-silicon binary oxide composite carbon nanotube ceramic fiber aerogel is obtained.

[0077] The embodiment provides a preparation method of a silicone rubber composite material for insulators, and specifically includes the following steps:

[0078] S1, 2.0 g of methyl orange is dissolved in a mixed solution of 50 mL of ethanol and 200 mL of deionized water, and 200 mL of a 1% pyrrole solution is slowly added under low temperature and light shielding at a stirring speed of 750 rpm, and then 80 mL of a 7.0% iron chloride hydrochloride solution is added dropwise, and the reaction is carried out for 10 h after the dropwise addition is completed, and the sample is left overnight, filtered, washed with water until it is colorless, and vacuum dried. A poly-pyrrole with a one-dimensional nanotube structure is prepared by a soft template method. The poly-pyrrole has excellent acid and oxidation resistance, and its stability is better than that of carbon materials, especially in an acidic or oxidizing environment. The poly-pyrrole nanotube has better compatibility with silicone rubber and more efficient stress transfer, and a poly-pyrrole nanotube is obtained.

[0079] S2, the polypyrrole nanotube described in step S1 is dispersed in 50 mL of deionized water, after ultrasonic treatment for 1 h, 16.0 g of anhydrous citric acid is added, and ultrasonic treatment is continued for 3 h, then diatomite is added, the amount of diatomite added is 1.0 g, diatomite can reduce the conductive path as an insulating component, its porous structure can adsorb impurity ions, reduce the conductivity and reduce the risk of leakage current, the micron-level porous structure and high specific surface area of diatomite can form physical cross-linking points with the molecular chains of silicone rubber, improve the tensile strength and tear strength, the chemical inertness of diatomite can also block the penetration of corrosive media and delay the aging of silicone rubber, ultrasonic treatment for 1 h, to obtain a polypyrrole nanotube and diatomite dispersion liquid for use, then 150 mL of water glass and 600 mL of deionized water are mixed uniformly, heated to 80°C, 6.25 mL of ethanol is added dropwise, then the polypyrrole nanotube and diatomite dispersion liquid is slowly added dropwise, the pH is adjusted to 6.0, 400 mL of ethanol is added, stirred for 0.5 h, and left overnight, centrifuged, the precipitate is washed with deionized water and ethanol for 5 times, vacuum dried, and passed through a 100 mesh screen, first, the polypyrrole nanotube is loaded in the diatomite pore, forming a diatomite-polypyrrole nanotube carrier, second, the silica generated by the hydrolysis of water glass is deposited on the surface of the diatomite-polypyrrole nanotube carrier and forms a dense wrapping layer, the coating of silica not only forms an armor effect on the surface of the carrier, improving the mechanical strength of the filler, but also protects the structure stability of the carrier in an acidic or alkaline environment, and also inhibits the electrical conductivity of the polypyrrole nanotube, optimizes the insulation performance, and the template effect of the carrier also effectively reduces the self-agglomeration phenomenon of silica, realizing the maximization of the effect of the combination of the three fillers, among them, the natural porous surface of diatomite and the abundant silicon hydroxyl groups provide physical adsorption and chemical bonding anchor points for silica, the addition of anhydrous citric acid in the pretreatment makes the surface of diatomite and polypyrrole nanotube negatively charged, and the interface bonding is enhanced by electrostatic interaction with silica, further promoting the directional coating of silica, to obtain a diatomite-polypyrrole nanotube-silica combined filler;

[0080] S3, dispersing N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane in 10 mL of 95% mass fraction ethanol solution, the amount of N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane added is 0.3 g, the methoxy group of the silane is hydrolyzed to form silicon hydroxyl group, which can form Si-O-Sil covalent bond with the hydroxyl group on the surface of the filler to modify the filler and enhance the dispersibility and interfacial compatibility of the filler in the matrix, and the amino group can react with the active groups such as carboxyl group in the aerogel to form chemical bonding, a small amount of acetic acid is added to adjust the pH to 5.0, and magnetic stirring is performed for 30 min, the obtained modified liquid is used, and then the diatomite polypyrrole nanotube silica composite filler described in step S2 is vacuum dried at 110°C for 1 h to remove the water on the surface, and then dispersed in 50 mL of anhydrous ethanol, ultrasonic treatment is performed for 20 min to form a filler suspension for use, then the modified liquid is slowly added to the filler suspension, magnetic stirring is performed at 80°C for 4 h, followed by ultrasonic treatment for 20 min, washed with ethanol and centrifuged 5 times, the precipitate is vacuum dried, the N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane forms an organic-inorganic hybrid layer on the surface of the composite filler, fills the micropores or defects in the composite filler, reduces the charge migration path, and thus enhances the insulation performance, the trimethoxy group of the N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane is hydrolyzed to form a cross-linked network with other silicon hydroxyl groups in the filler, which improves the mechanical properties such as tensile strength and wear resistance, the hydrophobic layer formed by the N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane on the surface of the filler can block the penetration of corrosive medium, and thus enhances the chemical corrosion resistance, and a diatomite polypyrrole nanotube silica coated modified filler is obtained;

[0081] S4, the methyl vinyl silicone rubber, titanium silicon binary oxide composite carbon nanotube ceramic fiber aerogel, diatomite polypyrrole nanotube silica coated modified filler described in step S3 are poured into a three-roll mill for mechanical mixing, the slow roller speed is 50 rpm, the middle roller speed is 150 rpm, and the fast roller speed is 400 rpm; after uniform mixing, the mixture is heated and pressurized for vulcanization by a flat vulcanizing machine, the vulcanization temperature is 160°C, the vulcanization time is 5 min, and the vulcanization pressure is 15 MPa; the titanium silicon binary oxide composite carbon nanotube ceramic fiber aerogel is uniformly dispersed in the aerogel through physical adsorption and chemical bonding, which also improves the dispersibility of the diatomite polypyrrole nanotube silica coated modified filler in the methyl vinyl silicone rubber, better embeds the three-dimensional network structure of the aerogel, and at the same time, the diatomite polypyrrole nanotube silica coated modified filler further modifies the aerogel, enhances the chemical cross-linking between the aerogel and the silicone rubber through active groups such as amino and silicon hydroxyl groups, significantly strengthens the interface bonding, reduces the movement of the silicone rubber molecular chain, improves the insulation performance, and the aerogel and the filler can form a uniform and dense cross-linked network in the silicone rubber matrix, which enhances the mechanical properties and barrier effect of the composite material, improves the tensile strength and chemical corrosion resistance, wherein the flexible organic chain of the diatomite polypyrrole nanotube silica coated modified filler can fill the pores of the aerogel, effectively reduce the interface gap, improve the mechanical interlocking effect, and also improve the damage of stress concentration to the aerogel, thereby obtaining a silicone rubber composite material for insulators.

[0082] Comparative Example 1

[0083] The present comparative example provides a silicone rubber composite material for insulators, which is different from Example 1 in that the titanium silicon binary oxide composite carbon nanotube ceramic fiber aerogel does not contain tetrabutyl titanate and multi-walled carbon nanotube dispersion liquid; the preparation method of the titanium silicon binary oxide composite carbon nanotube ceramic fiber aerogel does not include step (1), and only the silica spinning sol is loaded into the syringe for operation in step (2); and the preparation method of the silicone rubber composite material for insulators is the same as that of Example 1.

[0084] Comparative Example 2

[0085] The present comparative example provides a silicone rubber composite material for insulators, which is different from Example 1 in that the diatomite polypyrrole nanotube silica coated modified filler does not contain polypyrrole nanotubes and diatomite; the preparation method of the titanium silicon binary oxide composite carbon nanotube ceramic fiber aerogel is the same as that of Example 1; and the preparation method of the silicone rubber composite material for insulators does not include step S1, and no diatomite is added in step S2, so that the polypyrrole nanotube and diatomite dispersion liquid is not formed.

[0086] Comparative Example 3

[0087] The comparative example provides a silicone rubber composite for insulators, which is different from example 1 in that the diatomite polypyrrole nanotube silica-coated modified filler does not contain N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane; the preparation method of the titanium-silicon binary oxide composite carbon nanotube ceramic fiber aerogel is the same as that of example 1; and the preparation method of the silicone rubber composite for insulators does not include step S3.

[0088] Experimental example 1

[0089] Insulation performance experiment

[0090] Test sample: the silicone rubber composite for insulators prepared by examples 1-4 and comparative examples 1-3.

[0091] Test method: the insulation resistivity of the test sample is tested according to “Determination of Insulation Resistivity of Vulcanized Rubber” (GB / T 1692-2008), wherein the sample size is 100 mm x 100 mm x 2 mm.

[0092] Figure 2 The volume resistivity results of examples 1-4 and comparative examples 1-3 are shown in the figure. As shown in the figure, the volume resistivity of examples 1-4 is 302-325 x 10 13 Ω·m, indicating good insulation performance; the volume resistivity of comparative examples 1-3 is 209-257 x 10 13 Ω·m, indicating general insulation performance; comparative example 1 does not contain tetrabutyl titanate and multi-walled carbon nanotube dispersion in the titanium-silicon binary oxide composite carbon nanotube ceramic fiber aerogel, which is not conducive to enriching the nanostructure of the aerogel, cannot better limit the movement of silicone rubber molecular chains, and cannot play the insulation barrier role of titanium dioxide, resulting in general insulation performance; comparative example 2 does not contain polypyrrole nanotubes and diatomite in the diatomite polypyrrole nanotube silica-coated modified filler, lacks the role of a template carrier, and silica occurs self-agglomeration, limiting the play of its insulation barrier role, resulting in general insulation performance; comparative example 3 does not contain N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane in the diatomite polypyrrole nanotube silica-coated modified filler, which cannot fill the micropores or defects in the combined filler, increasing the charge migration path, resulting in general insulation performance.

[0093] Experimental example 2

[0094] Mechanical performance experiment

[0095] Test sample: the silicone rubber composite for insulators prepared by examples 1-4 and comparative examples 1-3.

[0096] Test method: According to the “determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber” (GB / T528-2009) and “determination of tear strength of vulcanized rubber or thermoplastic rubber” (GB / T529-2008), the tensile properties and tear properties of the test sample were tested respectively.

[0097] Figure 3 The mechanical property results of examples 1-4 and comparative examples 1-3 are shown in the figure; as shown in the figure, the tensile strength, elongation at break and tear strength of examples 1-4 are 7.2-7.6 MPa, 349-368%, 14.8-15.7 kN / mm respectively, indicating that the mechanical properties are strong; the tensile strength, elongation at break and tear strength of comparative examples 1-3 are 5.1-6.5 MPa, 260-304%, 11.3-13.6 kN / mm respectively, indicating that the mechanical properties are weak; comparative example 1 does not contain tetrabutyl titanate and multi-walled carbon nanotube dispersion in the titanium-silicon binary oxide composite carbon nanotube ceramic fiber aerogel, which is not conducive to improving the brittle fracture of the silica ceramic fiber aerogel containing only silica ceramic fiber aerogel, resulting in weak mechanical properties; comparative example 2 does not contain polypyrrole nanotube and diatomite in the diatomite polypyrrole nanotube silica coated modified filler, and the silica cannot form a coating layer, so it cannot improve the mechanical strength of the filler through the armor effect, resulting in weak mechanical properties; comparative example 3 does not contain N- (β-aminoethyl) -γ-aminopropyl trimethoxysilane in the diatomite polypyrrole nanotube silica coated modified filler, which cannot be condensed and crosslinked with the silicon hydroxyl groups in the combined filler, resulting in weak mechanical properties.

[0098] Experimental example 3

[0099] Chemical corrosion resistance experiment

[0100] Test sample: the silicone rubber composite material for insulators prepared by examples 1-4 and comparative examples 1-3.

[0101] Test method: 3.5% concentration of sodium chloride solution and pH 5.6 acid solution were prepared to simulate the salts and acidic substances in natural pollutants, and the test samples were respectively immersed in the sodium chloride solution and the acid solution for 72 hours, then after taking out, the pollution flashover voltage test was carried out under the application of alternating voltage in the normal temperature environment, wherein the electrode spacing was 10 mm, the voltage rising rate was 0.5 kV / s, the flashover voltage value was recorded, the average value was taken for 5 times, the pollution flashover voltage after immersion was obtained, and then the pollution resistance coefficient was calculated by the ratio of the pollution flashover voltage before and after immersion.

[0102] Figure 4The pollution resistance coefficient results of examples 1-4 and comparative examples 1-3 are shown in the figure; as shown in the figure, the pollution resistance coefficient of examples 1-4 is 0.95-1.00, indicating that the chemical corrosion resistance is better; the pollution resistance coefficient of comparative examples 1-3 is 0.69-0.83, indicating that the chemical corrosion resistance is not good; the titanium silicon binary oxide composite carbon nanotube ceramic fiber aerogel in comparative example 1 does not contain tetrabutyl titanate and multi-walled carbon nanotube dispersion, which is not conducive to the formation of a stable and rich aerogel network, thereby hindering the penetration of corrosive media, resulting in poor chemical corrosion resistance; the diatomite polypyrrole nanotube silica coated modified filler in comparative example 2 does not contain polypyrrole nanotubes and diatomite, lacking a template carrier, which cannot provide physical adsorption and chemical bonding anchoring sites for silica, is not conducive to the directional growth of silica, and limits the interfacial bonding of the filler and the titanium silicon binary oxide composite carbon nanotube ceramic fiber aerogel, thereby failing to form a uniform and dense network barrier, hindering the penetration of corrosive media, resulting in poor chemical corrosion resistance; the diatomite polypyrrole nanotube silica coated modified filler in comparative example 3 does not contain N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane, which cannot form a hydrophobic layer on the surface of the combined filler, hindering the penetration of corrosive media, resulting in poor chemical corrosion resistance.

[0103] The above experimental results show that the insulation performance, mechanical properties and chemical corrosion resistance of examples 1-4 of the present application are significantly better than those of comparative examples 1-3, wherein the insulation of example 1 using titanium silicon binary oxide composite carbon nanotube ceramic fiber aerogel, diatomite polypyrrole nanotube silica coated modified filler is better, the mechanical properties are stronger, and the chemical corrosion resistance is better. The titanium silicon binary oxide composite carbon nanotube ceramic fiber aerogel is used as a dispersion carrier for the diatomite polypyrrole nanotube silica coated modified filler, which improves the interfacial compatibility and bonding force in the silicone rubber matrix, forms a uniform and dense network structure, not only effectively reduces the movement of silicone rubber molecular chains, optimizes the insulation performance, but also enhances the mechanical strength and barrier effect of the composite material, improves the tensile strength and chemical corrosion resistance, and is conducive to the stable performance of the insulation performance.

[0104] Although embodiments of the present application have been shown and described, it will be understood by those having ordinary skill in the art that various changes, modifications, substitutions and alterations can be made thereto without departing from the principles and spirit of the present application.

[0105] The above describes the present application and its embodiments, which are not limiting, and the embodiments shown in the drawings are only one of the embodiments of the present application, and the actual application is not limited thereto. In summary, if a person skilled in the art is inspired by it, without departing from the purpose of the present application, without creative design, similar ways and embodiments of the technical solution should belong to the protection scope of the present application.

Claims

1. A silicone rubber composite for insulators, characterized by: The silicon rubber composite material for insulators comprises the following components in parts by weight: titanium silicon binary oxide composite carbon nanotube ceramic fiber aerogel 20-30 parts, diatomite polypyrrole nanotube silica coated modified filler 50-60 parts, and methyl vinyl silicone rubber 80-100 parts; the titanium silicon binary oxide composite carbon nanotube ceramic fiber aerogel comprises the following components in parts by weight: silica spinning sol 65-75 parts, and tetrabutyl titanate and multi-walled carbon nanotube dispersion liquid 25-35 parts; the diatomite polypyrrole nanotube silica coated modified filler comprises the following components in parts by weight: diatomite polypyrrole nanotube silica combined filler 50-60 parts, and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane 3-5 parts.

2. A process for the production of a silicone rubber composite material for insulators according to claim 1, characterized in that: Specifically comprising the following steps: S1, 1.0-2.0 g of methyl orange is dissolved in a mixed solution of 50 mL of ethanol and 200 mL of deionized water, 200 mL of 1% pyrrole solution is slowly added under low temperature and light shielding at a stirring speed of 650-750 rpm, 80 mL of 6.0-7.0% iron chloride hydrochloride solution is added drop by drop, the reaction is carried out for 10-12 h after the dropwise addition is completed, it is left overnight, it is filtered, it is washed with water until it is colorless, and it is vacuum dried to obtain polypyrrole nanotubes; S2, the polypyrrole nanotubes in step S1 are dispersed in 50 mL of deionized water, 16.0-18.0 g of anhydrous citric acid is added after ultrasonic treatment for 1-2 h, ultrasonic treatment is continued for 3-4 h, diatomite is then added, and ultrasonic treatment is carried out for 1-2 h to obtain a polypyrrole nanotube and diatomite dispersion liquid for use, 150-200 mL of water glass and 600 mL of deionized water are mixed uniformly, the temperature is raised to 70-80°C, 6.25 mL of ethanol is added drop by drop, then the polypyrrole nanotube and diatomite dispersion liquid is slowly added drop by drop, the pH is adjusted to 6.0, 400 mL of ethanol is added, stirring is carried out for 0.5-1 h, it is left overnight, it is centrifuged, the precipitate is washed with deionized water and ethanol for 3-5 times, it is vacuum dried, and it is sieved through a 80-100 mesh screen to obtain diatomite polypyrrole nanotube silica combined filler; S3, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane is dispersed in 10 mL of 95% ethanol solution, a small amount of acetic acid is added to adjust the pH to 4.0-5.0, magnetic stirring is carried out for 30-60 min, and the obtained modified liquid is used for use, the diatomite polypyrrole nanotube silica combined filler in step S2 is first vacuum dried at 100-110°C for 1-2 h to remove the surface moisture, then it is dispersed in 50 mL of anhydrous ethanol, ultrasonic treatment is carried out for 20-30 min to form a filler suspension for use, then the modified liquid is slowly added to the filler suspension, magnetic stirring is carried out at 60-80°C for 4-6 h, ultrasonic treatment is then carried out for 20-30 min, the filler is washed and centrifuged for 3-5 times, and the precipitate is vacuum dried to obtain diatomite polypyrrole nanotube silica coated modified filler; S4, methyl vinyl silicone rubber, titanium silicon dioxide composite carbon nanotube ceramic fiber aerogel, diatomite polypyrrole nanotube silica coated modified filler described in step S3 into three roll mill for mechanical mixing, slow roller speed 30-50 rpm, medium roller speed 100-150 rpm, fast roller speed 200-400 rpm, after mixing evenly, the mixture is heated and pressurized by flat plate vulcanizing machine, vulcanization temperature 120-160℃, vulcanization time 5-10 min, vulcanization pressure 10-15 MPa, to get silicone rubber composite material for insulator.

3. The method for preparing a silicone rubber composite for an insulator according to claim 2, characterized by: In step S2, the amount of diatomite added is 1.0-2.0g.

4. The method for preparing a silicone rubber composite for an insulator according to claim 3, characterized by: In step S3, the amount of N-(β-aminoethyl)-γ-aminopropyl trimethoxysilane added is 0.3-0.5g.

5. The method of claim 4, wherein the silicone rubber composite for insulators is prepared by the steps of: a) mixing the components of the silicone rubber composite for insulators; b) curing the silicone rubber composite for insulators; and c) removing the silicone rubber composite for insulators from the mold. The preparation method of the titanium silicon dioxide composite carbon nanotube ceramic fiber aerogel specifically includes the following steps: (1) 1.0-2.0g of multi-walled carbon nanotubes is added to 40mL of mixed acid solution for ultrasonic treatment for 1-2h, in the mixed acid solution, the volume ratio of mass fraction 98% sulfuric acid and mass fraction 68% nitric acid is 3:1, and then it is placed in a 60-80℃ water bath for heating and refluxing for 4-6h, centrifugal washing until neutral, drying, to obtain pretreated multi-walled carbon nanotubes; (2) 20.0-40.0g of tetraethyl orthosilicate, 6-12mL of water, 6-10mL of anhydrous ethanol and 0.14-0.28g of oxalic acid are stirred and mixed for 6-8h to prepare a silica precursor sol solution for standby use, 0.5-1.0g of polyvinyl butyral is added to 10mL of anhydrous ethanol and stirred and dissolved, then mixed with the silica precursor sol solution, stirring speed 100-200rpm, stirring time 3-4h, to prepare a silica spinning sol for standby use, then 25.0-45.0g of tetrabutyl titanate and 220-380mL of glacial acetic acid are stirred for 3-4h, then the pretreated multi-walled carbon nanotubes in step (1) are added, stirring for 30-50min, to prepare a tetrabutyl titanate and multi-walled carbon nanotube dispersion liquid for standby use, then the silica spinning sol and the tetrabutyl titanate and multi-walled carbon nanotube dispersion liquid are stirred and mixed for 4-6h, the obtained composite spinning liquid is loaded into a syringe, a 7# needle is selected as the spinning needle tube, the electrostatic pressure is 18-25kV, the distance between the needle and the receiver is 10-20cm, the liquid feeding rate of the push pump is 0.3-0.7mL / h, the receiving roller speed is 30rpm, the collected nanofiber membrane is placed in a crucible and put into a muffle furnace for calcination, the temperature rising speed is 5℃ / min, the temperature is kept at 800-900℃ for 20-30min, to obtain a composite ceramic fiber membrane; (3) the composite ceramic fiber membrane in step (2) is dispersed in 200mL of deionized water, ultrasonic treatment for 1-2h, then poured into a mold, placed in a liquid nitrogen bath for rapid freezing, then the frozen sample is put into a freeze dryer, frozen at-50℃ for 24-36h, to obtain a titanium silicon dioxide composite carbon nanotube ceramic fiber aerogel.

6. The method of claim 5, wherein the silicone rubber composite for insulators is prepared by the steps of: In step (1), the multi-walled carbon nanotube has a tube diameter of 5-15 nm and a length of 1-2 μm. In step (1), the multi-walled carbon nanotube has a tube diameter of 5-15 nm and a length of 1-2 μm.

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