Polyethylene electricity-water mixed branch self-repairing composite material doped with modified nano inorganic particles and preparation method of polyethylene electricity-water mixed branch self-repairing composite material

Abstract

The preparation method comprises the following steps: carrying out degassing treatment on a silane coupling agent and acrylic ester, carrying out silane coupling agent and acrylic ester modification on the surface of nano silicon dioxide, setting parameters of a torque rheometer, carrying out ultrasonic treatment on the surface of the nano silicon dioxide, carrying out ultrasonic treatment on the surface of the nano silicon dioxide, and carrying out ultrasonic treatment on the surface of the nano silicon dioxide to obtain the modified nano inorganic particle-doped polyethylene electric-water mixed branch self-repairing composite material. And melting, blending and grafting. And carrying out material melting, cross-linking reaction and vacuum drying to obtain the polyethylene electricity-water mixed branch self-repairing composite material doped with the modified nano inorganic particles. The polyethylene composite insulating material has the self-repairing capability of electricity and water mixed branches, the comprehensive performance of the polyethylene composite insulating material is superior to that of a novel grafted modified PE composite insulating power cable material of a traditional LDPE cable, the service life of the cable in China is further prolonged, and the insulating performance of the cable in China is further improved.

Description

Technical Field

[0001] The present invention relates to the research field of self - healing technology of insulating materials, and specifically to a polyethylene electro - hydro - mixed tree self - healing composite material doped with modified nano - inorganic particles and a preparation method thereof. Background Art

[0002] Polyethylene cables are widely used in modern power grids due to their reliable electrical, heat - resistant and mechanical properties. However, during the manufacturing and installation process, certain microscopic defects are inevitably caused in the cables. During the production and manufacturing of cables, due to process limitations, micro - cracks, holes and other tiny defects will inevitably appear in the insulation layer. During the laying and operation of cables, the combined action of long - term electro - thermal stress, chemical corrosion, over - voltage and other reasons will accelerate the aging of the insulation. During the cable installation construction, the mechanical force exerted on the cable body and its surroundings will also make the number and depth of microscopic defects more serious. Moisture enters the polyethylene insulation through various ways and channels such as air, precipitation, and land environmental conditions, and under the action of an electric field voltage, it moves along the electric field lines and reaches the cavity defects, thus triggering water trees. Some of these water trees evolve into electric trees, causing electric field distortion, and ultimately leading to the breakdown of the cable insulation. These tiny aging defects often form deep in the material structure. It is difficult for existing technologies to detect the tiny aging defects in the cable insulation layer during operation, and only the local discharge method after power outage can be used to detect the defect damage. Except for overall replacement, there is no more effective treatment method for the time being.

[0003] Although there are external - type self - healing insulating materials represented by the micro - capsule self - healing system, the method theory is relatively simple. However, the number of times of micro - capsule repair is limited, the repair position is fixed, the process is complex, some catalysts are relatively expensive, and it is difficult to ensure the uniform dispersion of micro - capsules. Uneven distribution will also cause air holes inside the material, reducing the self - healing efficiency of the material. Therefore, it is necessary to develop a polyethylene composite insulating material with the intrinsic self - healing ability of electro - hydro - mixed trees to fundamentally explore methods to extend the service life of insulating materials. Based on the above existing problems, the purpose of the present invention is to provide a polyethylene self - healing composite material based on doping and grafting modified SiO 2 to successfully develop a new type of PE composite insulating power cable material with comprehensive performance superior to traditional LDPE cables, and further improve the service life and insulation performance of cables in China. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art. The present invention provides a polyethylene electro - hydro - mixed tree self - healing composite material doped with modified nano - inorganic particles and a preparation method thereof, which is an extension and development of the self - healing technology of insulating materials.

[0005] The purpose of the present invention is achieved through the following technical solutions: A polyethylene electro-hydro hybrid dendritic self-healing composite material doped with modified nano-inorganic particles and its preparation method, including degassing treatment of silane coupling agent and acrylate, modification of nano-silica surface with silane coupling agent and acrylate, setting parameters of torque rheometer, and melt blending. Then, through material melting, cross-linking reaction, and vacuum drying, a polyethylene electro-hydro hybrid dendritic self-healing composite material doped with modified nano-inorganic particles is obtained. The specific steps are as follows: (1) Degassing treatment of silane coupling agent and acrylate: Pour the silane coupling agent and acrylate into two washing bottles respectively, introduce high-purity nitrogen gas into each to displace the air dissolved in the solution, let it stand, and then introduce it into a reflux device equipped with sodium chips and acetone. After heating and refluxing and distilling off, collect and reserve. (2) Graft modification on the surface of nano-silica: First, dry pure silica in an oven at 120 °C overnight to remove water, then place it in a three-necked flask equipped with a thermometer and a reflux condenser. Under a nitrogen stream and magnetic stirring, with an additional funnel, control the temperature with a rapeseed oil bath. At 40 °C, mix 20 g of silica with 200 mL of toluene for 15 minutes. After the temperature stabilizes, add 20 g of KH550 and continuously stir at 40 °C for 4 hours. Filter through a Buchner funnel, and wash the precipitate with toluene 4 times to obtain a white powder SiO 2 -KH550. Then put the SiO 2 -KH550 containing active amino groups into a round-bottom flask, control the temperature with an oil bath. Stir 20 g of SiO 2 -KH550 strongly in anhydrous toluene for 10 minutes, then raise the temperature to 90 °C. After the temperature stabilizes, add 121 g of DPGDA monomer according to the molar ratio of 0.15 / 0.5 (KH550 / DPGDA), and strongly stir and react for 10 hours. Cool to room temperature and then filter under vacuum. Wash the product with anhydrous toluene 3 times and anhydrous ethanol 1 time successively, and vacuum dry to obtain a white powder SiO 2 -K-D. (3) Setting parameters of torque rheometer: Turn on the instrument switch and the computer, set the temperatures of the first, second, and third zones of the torque rheometer to 110 °C, set the rotation speed to 50 r / min, and then enable the communication connection. Start heating, and after the temperature stabilizes at 110 °C ± 2 °C, start the torque rheometer. Weigh about 40 g of pure low-density polyethylene to clean the torque rheometer, and repeat the cleaning process 2 - 3 times. Only when there are no impurities in the head of the torque rheometer and no foreign objects in the screw can the next experiment be started. (4) Melt blending: Put 40 g of low-density polyethylene, graft-modified nano-silica with different mass fractions, and antioxidant 1010 into the torque rheometer. Wait until the low-density polyethylene is in a molten state and the torque is stable. Then add photoinitiator 184 and continue to knead for 4 minutes, and stop the machine. Finally, add catalyst dibutyltin dilaurate and knead for 2 minutes. Take out the uniformly kneaded composite material and cut it into small particles for standby. (5) Melting of the material: Make a corresponding mold according to the shape of the sample, calculate the mass of the required composite material, set the temperature of the flat vulcanizer to 110 °C, put in the composite material, after heating for 15 minutes, increase the pressure by 5 Mpa every 5 minutes, observe the pressure gauge in time, and supplement the pressure in time when the pressure is insufficient; (6) Cross-linking reaction: Set the temperature of another flat vulcanizer to 175 °C, put the material in (7) into it, increase the pressure to 15 MPa, supplement the pressure at any time, and fully cool the sample after heating for 35 minutes; (7) Vacuum drying: Set the temperature of the vacuum drying oven to 80 °C, conduct vacuum drying treatment on the composite polyethylene material to obtain a polyethylene electro-hydro hybrid tree self-healing composite material doped with modified nano-inorganic particles.

[0006] In the technical solution of the present invention: The silane coupling agent described in (1) is KH550, and the acrylate is dipropylene glycol diacrylate (DPGDA).

[0007] In the technical solution of the present invention: The particle size of the nano-silica described in (2) is 20 nm.

[0008] In the technical solution of the present invention: The purpose of the cleaning described in (3) is to eliminate the errors brought by impurities to the experiment.

[0009] In the technical solution of the present invention: The addition amount of the graft-modified silica particles described in (4) accounts for 0.5% - 3% of the total weight of the low-density polyethylene. The dosage of the antioxidant 1010 is 0.3% of the total weight of the low-density polyethylene. The addition amount of the catalyst dibutyltin dilaurate accounts for 0.5% of the total weight of the low-density polyethylene and the addition amount of the photoinitiator 184 accounts for 0.5% of the total weight of the low-density polyethylene.

[0010] In the technical solution of the present invention: The purpose of increasing the pressure in (5) is to fully shape the material so that the impurity gas in the material can be fully discharged.

[0011] In the technical solution of the present invention: The purpose of step (6) is to fully mix the inorganic particles with the low-density polyethylene.

[0012] In the technical solution of the present invention: The purpose of step (7) is to reduce the influence of the residual stress inside the sample on the sample.

[0013] Compared with the prior art, the advantages of the present invention are as follows: (1) Through the grafting reaction, the water-curing property of the silane coupling agent and the photo-curing property of the acrylate are successfully grafted onto SiO 2 to make it have the self-healing properties of electrical tree and water tree. (2) Under the action of UV, the photoinitiator (PI) is excited and transformed from the ground state to the excited state (PI*), thereby generating active free radicals (R·). The resulting free radicals (R·) combine with the C═C of acrylate in the repair agent, and a continuous addition reaction occurs, causing the molecular chain to grow. A cured material with a network structure is generated to fill the holes of the electret, and acrylate itself is a voltage stabilizer, which improves the insulation of LDPE. (3) At room temperature, through the action of a catalyst, the silane coupling agent reacts with water to generate oligomers, consuming the moisture in the insulator. Moreover, the organic polymer generated after the reaction can fill the micropores, thereby eliminating the water tree and restoring the insulation performance of the water tree-aged cable. The silane coupling agent is not easily decomposed at high temperatures, has the characteristics of high voltage resistance and good insulation performance, and its performance is similar to that of polyethylene, effectively filling the water tree cavities. (4) The incorporation of modified SiO 2 improves its distribution in the matrix and enhances its insulation and mechanical properties. Description of the Drawings

[0014] Figure 1 It is a PDC polarization test chart. In the chart, 1 is the comparative example three without self-healing composite insulation material before the hybrid tree aging, 2 is the self-healing composite insulation material prepared by Method 1 before the hybrid tree aging, 3 is the comparative example three without self-healing composite insulation material after the hybrid tree aging, and 4 is the self-healing composite insulation material prepared by Method 1 after the hybrid tree aging.

[0015] Figure 2 It is a relative permittivity test chart. In the chart, 1 is the comparative example three without self-healing composite insulation material, 2 is the self-healing composite insulation material prepared by Comparative Example 1, 3 is the self-healing composite insulation material prepared by Embodiment 2, 4 is the self-healing composite insulation material prepared by Comparative Example 2, and 5 is the self-healing composite insulation material prepared by Embodiment 1.

[0016] Figure 3 It is a SEM chart of tree aging. In the chart, 1 is a schematic diagram of the electro-hydro hybrid tree defect of the comparative example three without self-healing composite insulation material, and 2 is a schematic diagram of the self-healing defect of the self-healing composite insulation material in Embodiment 1.

[0017] Figure 4 It is a tree morphology chart formed after the accelerated electro-hydro hybrid tree aging test. In the chart, the left figure is a schematic diagram of the hybrid tree defect of the comparative example three without self-healing composite insulation material, and the right figure is a schematic diagram of the self-healing hybrid tree defect of the self-healing composite insulation material in Embodiment 1.

[0018] Figure 5 It is a process schematic diagram of the graft-modified SiO 2 of the present invention.

[0019] Figure 6 Schematic diagram of the electro-hydro hybrid tree self-healing process of the self-healing composite material of the present invention.

[0020] Figure 7 Schematic diagram of the composite material manufactured by the present invention. Specific embodiments The present invention will be described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made. These all belong to the protection scope of the present invention.

[0021] Specific embodiment 1. A polyethylene electro-hydro hybrid tree self-healing composite material doped with modified nano-inorganic particles and its preparation method are specifically completed according to the following steps: (1) Degassing treatment of silane coupling agent and acrylate: Pour the silane coupling agent and acrylate into two washing bottles respectively, and introduce high-purity nitrogen gas respectively to displace the air dissolved in the solution. After standing, introduce them into a reflux device equipped with sodium chips and acetone, heat and reflux to distill out and collect for standby. (2) Modification of nano-silica surface with silane coupling agent: First, dry pure silica in an oven at 120 °C overnight to remove water, then place it in a three-necked flask equipped with a thermometer and a reflux condenser. Under a nitrogen stream and magnetic stirring, with an additional funnel, control the temperature with a rapeseed oil bath. At 40 °C, mix 20 g of silica with 200 mL of toluene for 15 minutes. After the temperature stabilizes, add 20 g of KH550 and continuously stir at 40 °C for 4 hours. Filter through a Buchner funnel, and wash the precipitate 4 times with toluene to obtain a white powder SiO 2 -KH550. Then put the SiO 2 -KH550 containing active amino groups into a round-bottom flask, control the temperature with an oil bath, stir 20 g of SiO 2 -KH550 strongly in anhydrous toluene for 10 minutes, then raise the temperature to 90 °C. After the temperature stabilizes, add 121 g of DPGDA monomer according to the molar ratio of 0.15 / 0.5 (KH550 / DPGDA), and strongly stir and react for 10 hours. After cooling to room temperature, filter under vacuum. The product is washed 3 times with anhydrous toluene and 1 time with absolute ethanol successively, and dried under vacuum to obtain a white powder SiO 2 -K-D. (3) Torque rheometer parameter setting: Turn on the instrument switch and the computer. Set the temperatures of the first, second, and third zones of the torque rheometer to 110 °C. After setting the rotation speed to 50 r / min, enable the communication connection. Start heating and wait for the temperature to stabilize at 110 °C, then start the torque rheometer. Weigh approximately 40 g of pure low-density polyethylene for cleaning the torque rheometer. The cleaning process lasts for 3 times. Only when there are no impurities in the head of the torque rheometer and no foreign objects in the screw can the next experiment be started. (4) Melt blending: Put 40 g of low-density polyethylene, graft-modified nano-silica, and antioxidant 1010 into the torque rheometer. The graft-modified nano-silica and antioxidant 1010 account for 1% and 0.3% of the total weight of low-density polyethylene respectively. Wait until the low-density polyethylene is in a molten state and the torque is stable. Then add photoinitiator 184 to it in sequence and continue mixing for 4 minutes. Its dosage accounts for 0.5% of the total weight of low-density polyethylene. Stop the machine. Finally, add catalyst dibutyltin dilaurate and mix for 2 minutes. Its dosage accounts for 0.5% of the total weight of low-density polyethylene. Take out the uniformly mixed composite material and cut it into small particles for standby. (5) Material melting: Make a 4 cm × 4 cm × 4 mm square mold according to the shape of the sample. Weigh the required mass of the composite material as 14.4 g. Set the temperature of the flat vulcanizing machine to 110 °C. Put the iron plate and the composite material wrapped with oily polyester film. After heating for 15 minutes, increase the pressure every 5 minutes. The pressure gauge values are 0 MPa, 5 MPa, 10 MPa, 15 MPa. Observe the pressure gauge in time and make up the pressure in time when the pressure is insufficient; (6) Crosslinking reaction: Set the temperature of another flat vulcanizing machine to 175 °C. Put the material in (5) into it, increase the pressure to 15 MPa, make up the pressure at any time, and fully cool the sample after heating for 35 minutes; (7) Vacuum drying: Set the temperature of the vacuum drying oven to 80 °C. Carry out vacuum drying treatment on the grafted composite polyethylene material to obtain a polyethylene electro-hydro hybrid tree self-healing composite material doped with modified nano-inorganic particles.

[0022] Comparative example 1: The difference between this comparative example and Embodiment 1 is that in Embodiment 1 (4), the modified SiO 2 accounts for 0.5% of the total weight of low-density polyethylene to obtain the raw material. Other steps and parameters are the same as those in Embodiment 1.

[0023] Embodiment 2: The difference between this embodiment and Embodiment 1 is that in Embodiment 1 (4), the modified SiO 2 accounts for 2% of the total weight of low-density polyethylene to obtain the raw material. Other steps and parameters are the same as those in Embodiment 1.

[0024] Comparative Example 2: The difference between this comparative example and Embodiment 1 is that in Embodiment 1 (4), the modified SiO 2 accounts for 3% of the total weight of low-density polyethylene. The raw materials are obtained. Other steps and parameters are the same as those in Embodiment 1.

[0025] Comparative Example 3: The difference between this comparative example and Embodiment 1 is that steps (1)-(2) of Embodiment 1 are not carried out, and silicon dioxide, photoinitiator 184, and catalyst dibutyltin dilaurate are not added in (4). Other steps and parameters are the same as those in Embodiment 1.

[0026] The low-density polyethylene used in the embodiments and comparative examples is produced by Beijing Yanshan Branch of China National Petroleum and Chemical Corporation, with the model LD100AC, a density of 0.9205 g / cm 3 , and a melt index of 2.0 g / min;

[0027] The photoinitiator 184 used in the embodiments and comparative examples is 1-hydroxycyclohexyl phenyl ketone, produced by Shanghai Aladdin Biochemical Technology Co., Ltd., with a melting point of 47-50 °C, a boiling point of 175 °C, and a density of 1.17 g / cm 3 ;

[0028] The antioxidant used in the embodiments and comparative examples is antioxidant 1010, produced by Dongguan Shanyi Plastic Co., Ltd., with a relative molecular mass of 1177.63 and a melting point of 115 °C.

[0029] The silane coupling agent used in the embodiments and comparative examples is γ-aminopropyltriethoxysilane (KH550), produced by Shanghai Aladdin Biochemical Technology Co., Ltd., with a density of 0.942 g / cm 3 , and a boiling point of 217 °C.

[0030] The acrylate used in the embodiments and comparative examples is dipropylene glycol diacrylate (DPGDA), produced by Shanghai Aladdin Biochemical Technology Co., Ltd., with a density of 1.05 g / cm 3 , and a boiling point of 119-121 °C.

[0031] The catalyst used in the embodiments and comparative examples is dibutyltin dilaurate, produced by Shanghai Aladdin Biochemical Technology Co., Ltd., with a density of 1.066 g / cm 3 , and a molecular weight of 631.56.

[0032] Figure 1It is a PDC polarization test diagram. In the diagram, 1 is the comparative example 3 without self-healing composite insulation material before the aging of the hybrid tree branches, 2 is the self-healing composite insulation material prepared by Method 1 before the aging of the hybrid tree branches, 3 is the comparative example 3 without self-healing composite insulation material after the aging of the hybrid tree branches, and 4 is the self-healing composite insulation material prepared by Method 1 after the aging of the hybrid tree branches.

[0033] From Figure 1 it can be seen that: the polarization currents of the self-healing composite insulation material prepared by Method 1 and the comparative example 3 without self-healing composite insulation material are very close before the aging of the hybrid tree branches, while the polarization current of the self-healing composite insulation material prepared by Method 1 is significantly lower than that of the comparative example 3 without self-healing composite insulation material after the aging of the hybrid tree branches.

[0034] Figure 2 It is a relative permittivity test diagram. In the diagram, 1 is the comparative example 3 without self-healing composite insulation material, 2 is the self-healing composite insulation material prepared by Comparative Example 1, 3 is the self-healing composite insulation material prepared by Embodiment 2, 4 is the self-healing composite insulation material prepared by Comparative Example 2, and 5 is the self-healing composite insulation material prepared by Embodiment 1.

[0035] From Figure 2 it can be seen that the relative permittivity of Embodiment 1 is much lower than that of Comparative Example 3. From this, it can be seen that the doping of a small amount of modified SiO 2 improves the insulation performance of LDPE. The relative permittivity of Comparative Example 2 is greater than that of Embodiment 2 which is greater than that of Comparative Example 1. From this, it can be seen that as the doping amount increases, its insulation characteristics will decline.

[0036] Figure 3 It is an SEM diagram. In the diagram, (a) is a schematic diagram of the water tree defect of the comparative example 3 without self-healing composite insulation material, and (b) is a schematic diagram of the self-healing water tree defect of the self-healing composite insulation material of Embodiment 1.

[0037] From Figure 3 it can be seen that a series of holes are generated in (a) after the electro-hydro hybrid tree branch aging, while the holes in (b) are significantly filled. It is proved that the embodiments of the present invention can repair the holes in time after the occurrence of electro-hydro tree holes.

[0038] Figure 4 It is a tree branch morphology diagram formed after the accelerated electro-hydro hybrid tree branch aging test. In the diagram, (a) is a schematic diagram of the tree branch defect of the comparative example 3 without self-healing composite insulation material, and (b) is a schematic diagram of the self-healing hybrid tree branch defect of the self-healing composite insulation material of Embodiment 1.

[0039] From Figure 4It can be seen that the length of the branch is the length from the tip of the steel needle to the bottom end of the branch. In the figure, the length of the branch in Comparative Example 3 (a) is significantly higher than that in Embodiment 1 (b). This shows that the composite material prepared by the present invention can significantly improve the electrical tree and water tree resistance of the polyethylene insulating material.

[0040] In summary, the polyethylene electro-hydro hybrid tree self-healing composite material doped with modified nano-inorganic particles prepared by the present invention can repair holes in time when multiple tree defects occur in the insulating material, and doping and modifying SiO 2 can effectively improve the insulation performance of the matrix.

Claims

1. A polyethylene electric-water hybrid dendrite self-repairing composite material doped with modified nano inorganic particles and a preparation method thereof, characterized in that: Nano-silicon dioxide with surface grafted silane coupling agent and acrylate is used as a blended inorganic material to form a composite structure of inorganic particles doped with polyethylene. Silane coupling agent and acrylate grafted SiO2 inorganic particles are obtained by regulating the grafting reaction of grafted monomers and inorganic particles, and a hydroelectric hybrid dendrite self-healing composite material is obtained by melt blending. The self-healing and dielectric properties of the composite material are regulated by the content of inorganic particles.

2. The nano-silica modified with a silane coupling agent on the surface according to claim 1, characterized in that: Silicon alcohols, acrylates and a small amount of siloxane molecules are introduced onto the surface of nano-silica. The grafted organic functional groups are well compatible with the polyethylene matrix, playing a role of linking and bridging between the inorganic SiO2 particles and the organic low-density polyethylene matrix, forming hydrogen bonds, improving the dispersion of nano-SiO2 particles in the matrix, and giving the material self-healing capabilities.

3. The polyethylene electric-water hybrid dendrite self-repairing composite material doped with modified nano inorganic particles according to claim 1, characterized in that: The silane coupling agent is KH550, and the acrylate is dipropylene glycol diacrylate (DPGDA).

4. A polyethylene electric-water hybrid dendrite self-repairing composite material doped with modified nano inorganic particles, characterized in that: The following steps are involved: (1) Degassing of silane coupling agent and acrylate: Pour the silane coupling agent and acrylate into two washing bottles respectively, introduce high-purity nitrogen into each bottle to replace the air dissolved in the solution, let it stand and then introduce it into a reflux device filled with sodium shavings and acetone, heat it under reflux and evaporate it, then collect it for later use. (2) Grafting modification on the surface of nano-silica: First, dry pure silica in an oven at 120°C overnight to remove water, then place it in a three-necked flask with a thermometer and reflux condenser, and add an additional funnel under nitrogen flow and magnetic stirring, and use rapeseed oil bath to control the temperature. Mix 20g of silica with 200mL of toluene at 40°C for 15 minutes, add 20g of KH550 after the temperature stabilizes, and continue stirring at 40°C for 4 hours. Filter through a Buchner funnel, and wash the precipitate with toluene 4 times to obtain white powder SiO2-KH550. Then put SiO2-KH550 containing active amine groups into a round-bottom flask and control the temperature with an oil bath. 20g SiO2-KH550 was vigorously stirred in anhydrous toluene for 10 minutes and then heated to 90°C. After the temperature stabilized, 121g DPGDA monomer was added according to a molar ratio of 0.15 / 0.5 (KH550 / DPGDA). The reaction was vigorously stirred for 10 hours, cooled to room temperature and vacuum filtered. The product was washed 3 times with anhydrous toluene and once with anhydrous ethanol, and vacuum dried to obtain white powder SiO2-KD. (3) Preparation of composite materials: low-density polyethylene, nano-silica modified with silane coupling agent and antioxidant 1010 are placed in a torque rheometer. After the low-density polyethylene is in a molten state and the torque is stable, the photoinitiator 184 is added in sequence and continued to be mixed. Finally, the catalyst dibutyl tin dilaurate is added and mixed. After melt blending, the cross-linked polyethylene composite material is made into the shape required for the test using a flat vulcanizer, and finally vacuum dried to obtain a polyethylene electric-water hybrid dendrite self-healing composite material doped with modified nano-inorganic particles.

5. The method for preparing the nano inorganic particle / silane coupling agent / acrylic acid grafted polyethylene electric-water hybrid dendrite self-repairing composite material according to claim 4, characterized in that: The particle size of the nano silicon dioxide is 20 nm, and the particle size of the nano zinc oxide is 20 nm.

6. The method for preparing the polyethylene electric-water hybrid dendrite self-repairing composite material doped with modified nano inorganic particles according to claim 4, characterized in that: Due to their nanoscale quantum effects and large specific surface area, nanoparticles can adsorb carriers in insulating materials to reduce their energy, thereby improving the insulating properties of insulating materials.

7. The method for preparing the polyethylene electric-water hybrid dendrite self-repairing composite material doped with modified nano inorganic particles according to claim 4, characterized in that: The modified silica will become a stress concentration point, which can consume energy and effectively stop the stress lines from developing into cracks, thereby enhancing the mechanical properties of the composite material.

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