All-organic nonlinear insulating material based on electron-donating group and preparation method of all-organic nonlinear insulating material

Abstract

According to the all-organic nonlinear insulating material based on the electron-donating group and the preparation method, polyolefin is used as a matrix of the material, and an organic small molecule filler containing the electron-donating group is introduced to form a uniformly dispersed composite structure, so that the nonlinear conductivity of the material is remarkably improved. The small organic molecules can be ethylene glycol diphenyl ether, nonylphenol polyoxyethylene ether, allyloxy polyoxyethylene ether or octadecyl dimethyl hydroxyethyl quaternary ammonium nitrate, and the mass fraction of the filler is 0.1-3 wt%. The preparation method comprises the following steps: melting the polyolefin matrix at 110-120 DEG C, adding the small organic molecule filler, and blending for 10-30 minutes at the rotating speed of 50-70 r / min. The material has excellent electric field homogenization capability in a high electric field, avoids the problem of inorganic filler agglomeration, has relatively low filler content and excellent processability, can be widely applied to the field of high-voltage electrical equipment such as transformers, switch equipment and mutual inductors, and effectively improves the insulating property and prolongs the service life of the equipment.

Description

Technical Field

[0001] The invention relates to the technical field of electrical insulating materials, and in particular to a fully organic nonlinear insulating material based on electron-donating groups and a preparation method thereof. Background Art

[0002] In modern power systems, as voltage levels gradually increase, the insulation materials of electrical equipment work for a long time under uneven strong electric fields. This environment will accelerate the aging of the insulation materials, affecting their service life and safety. Therefore, regulating the uneven distribution of electric fields has become a research hotspot.

[0003] At present, nonlinear insulating materials have become an effective means to solve such problems due to their ability to self-homogenize the electric field distribution. Existing nonlinear insulating materials are usually composed of a polymer matrix and an inorganic semi-conductive filler (such as zinc oxide, silicon carbide and carbon black). Among them, the inorganic semi-conductive filler plays a role in improving the nonlinear conductivity characteristics in the material, which can effectively accelerate the dissipation of the internal charge of the insulating material, thereby realizing the adaptive regulation of the distorted electric field.

[0004] However, this type of traditional nonlinear insulating material has some disadvantages that cannot be ignored. First, its nonlinear conductivity characteristics are closely related to the filler content. Only when the filler content exceeds the percolation threshold can the filler particles form a conductive network, thereby giving the material nonlinear characteristics. Usually, this percolation threshold is very high. For example, the percolation threshold of ZnO / silicone rubber nonlinear insulating material is 33vol%, while the percolation threshold of SiC / silicone rubber nonlinear insulating material is 30wt%. Such a high filler content not only aggravates the agglomeration of the filler, but also has an adverse effect on the processing and mechanical properties of the material. In addition, the poor compatibility of inorganic fillers with the polymer matrix will further reduce the processing performance and stability of the material.

[0005] In recent years, all-organic composite insulating materials have gradually attracted attention as a new type of dielectric material. By blending or grafting organic small molecules with high electron affinity into the polymer matrix, all-organic composite materials can introduce more deep traps in the matrix, thereby restraining the migration of carriers, reducing the conductivity and increasing the breakdown field strength. This type of organic small molecule usually has a strong electron-withdrawing ability, which can increase the electron affinity of the material. However, in addition to electron-withdrawing groups, organic small molecules containing electron-donating groups also have potential application value. In contrast to electron-withdrawing groups, organic small molecules containing strong electron-donating groups have higher lowest unoccupied molecular orbital (LUMO) energy levels. After being doped with the polymer matrix, they are expected to further improve the nonlinear conductivity characteristics, while avoiding the problems of poor dispersibility and compatibility of inorganic fillers in the polymer matrix.

[0006] However, the current research on the influence of small molecules containing electron-donating groups on the properties of insulating materials is still in a blank stage, and there is no relevant research report. Based on this technical blank, the present invention proposes a fully organic nonlinear insulating material based on electron-donating groups. By optimizing the material composition and preparation method, it effectively solves the problems of poor dispersion of inorganic fillers, serious agglomeration, and processing difficulties caused by high filler content, providing a new research direction for the development of fully organic nonlinear insulating materials. Summary of the Invention

[0007] In order to solve the problems of poor compatibility between inorganic fillers and polymer matrix, easy agglomeration, and processing difficulties in existing nonlinear insulating materials, the present invention provides a fully organic nonlinear insulating material based on electron-donating groups and its preparation method. By doping organic small molecules containing electron-donating groups in the polyolefin matrix, excellent nonlinear conductivity characteristics are achieved at a relatively low filler concentration, and the processing performance and mechanical properties of the material are effectively improved.

[0008] In a possible implementation manner, the fully organic nonlinear insulating material includes:

[0009] Using polyolefin as the matrix;

[0010] Organic small molecules containing electron-donating groups as fillers, and the mass fraction of the organic small molecules is 0.1-3 wt%.

[0011] Further, the polyolefin is any one of low-density polyethylene, high-density polyethylene, or polypropylene.

[0012] Further, the organic small molecule is one of ethylene glycol diphenyl ether, nonylphenol polyoxyethylene ether, allyloxy polyoxyethylene ether, or octadecyl dimethyl hydroxyethyl ammonium nitrate.

[0013] In a possible implementation manner, a preparation method of a fully organic nonlinear insulating material based on electron-donating groups is provided, including the following steps:

[0014] Step 1: Melting the polyolefin matrix in a torque rheometer;

[0015] Step 2: Adding organic small molecule fillers with a mass fraction of 0.1-3 wt%;

[0016] Step 3: Blending for 10-30 min under the conditions of a temperature of 110-120 °C and a rotation speed of 50-70 r / min to obtain a fully organic nonlinear insulating material based on electron-donating groups.

[0017] Further, the melting temperature in Step 1 is 110-120 °C.

[0018] Further, the polyolefin matrix is any one of low-density polyethylene, high-density polyethylene, or polypropylene.

[0019] Further, the organic small molecule is one of ethylene glycol diphenyl ether, nonylphenol polyoxyethylene ether, allyloxy polyoxyethylene ether, or octadecyl dimethyl hydroxyethyl quaternary ammonium nitrate.

[0020] In a possible implementation, an application of a fully organic nonlinear insulating material based on an electron-donating group is provided. The material is applied in high-voltage electrical equipment to homogenize the electric field distribution and improve the nonlinear conductivity characteristics of the material.

[0021] Based on the above technical solutions, the fully organic nonlinear insulating material of the present invention based on an electron-donating group realizes the improvement of the nonlinear conductivity characteristics of the composite material by doping an organic small molecule containing an electron-donating group in the polyolefin matrix, while avoiding the problems of poor compatibility and easy agglomeration of inorganic fillers in the polymer matrix. In addition, the present invention optimizes the blending process to achieve excellent nonlinear conductivity characteristics at a low filler concentration, improving the processing performance and mechanical properties of the material, and providing new ideas for the design and application of new nonlinear insulating materials.

[0022] Compared with the prior art, the present invention has the following technical effects:

[0023] 1. Reduces the requirement for filler content and improves the processing performance

[0024] Traditional nonlinear insulating materials usually rely on the percolation effect of inorganic semiconductive fillers to achieve nonlinear characteristics, but the filler content usually needs to reach more than 30% to form a conductive network. In contrast, the present invention can achieve excellent nonlinear conductivity characteristics even under the condition of a low filler content (0.1 - 3 wt%) by introducing an organic small molecule with an electron-donating group. The low filler content not only reduces the processing difficulty of the material but also improves the mechanical properties and service life of the material.

[0025] 2. Enhances the electric field homogenization ability of the material and extends the insulation life

[0026] By introducing an organic small molecule with an electron-donating group, the insulating material of the present invention can effectively enhance the electric field homogenization effect, exhibit excellent charge regulation ability under non-uniform strong electric field conditions, reduce the damage of local electric field distortion to the material, and thus extend the life of the insulating material.

[0027] 3. Avoids the agglomeration phenomenon of inorganic fillers and improves the material stability

[0028] Due to the poor compatibility between traditional inorganic fillers and polymer matrices, agglomeration is likely to occur, which affects the uniformity and electrical properties of the materials. In the present invention, organic small molecules with electron-donating groups are used as fillers, which not only avoid the agglomeration problem of inorganic fillers, but also improve the compatibility of the materials and enhance the overall stability.

[0029] 4. Optimize the blending process to improve the material uniformity

[0030] During the preparation process, the present invention optimizes key parameters such as blending temperature, rotation speed, and time, enabling the organic small molecules to be uniformly distributed in the polyolefin matrix, thereby enhancing the non-linear conductivity characteristics of the materials. By adopting a blending temperature of 110 - 120 °C, a rotation speed of 50 - 70 r / min, and a blending time of 10 - 30 min, the uniformity and stability of the internal microstructure of the materials are ensured.

[0031] 5. Wide application prospects

[0032] Since the all-organic non-linear insulating material provided by the present invention has excellent non-linear conductivity characteristics and electric field homogenization ability, it can be widely applied to high-voltage electrical equipment, especially suitable for occasions with high requirements for the performance of insulating materials such as power transformers, switchgear, and instrument transformers, providing a strong guarantee for the safe and stable operation of the power system.

[0033] In another possible implementation, the all-organic non-linear insulating material based on electron-donating groups can further enhance the non-linear conductivity performance of the material by adjusting different types of electron-donating group molecules. For example, by optimizing the molecular structure and electron distribution of the electron-donating groups, the trap density of the composite material can be effectively increased, further enhancing the electric field homogenization ability of the material. In addition, by introducing electron-donating groups with different LUMO energy levels, precise regulation of the non-linear characteristics of the material can be achieved to meet the requirements of different electrical application scenarios.

[0034] In summary, the all-organic non-linear insulating material based on electron-donating groups proposed by the present invention has significant advantages in terms of material formulation, preparation process, and application performance, providing a new technical path for the development and application of high-performance insulating materials. Description of the Drawings

[0035] Figure 1 It is the current density - electric field strength relationship curve of the examples and the control examples.

[0036] Figure 2 It is the non-linear coefficient of the examples and the control examples.

[0037] Figure 3 It is the LUMO energy level of the corresponding organic small molecule filler in the examples. Detailed Embodiments

[0038] The present invention prepares and verifies an all-organic nonlinear insulating material based on electron-donating groups through different embodiments. Different types of electron-donating group organic small molecule fillers are used and blended with a polyolefin matrix to obtain a composite material with excellent properties.

[0039] Example 1:

[0040] In this example, the polymer matrix used is low-density polyethylene (LDPE), and the melting temperature is set at 110 °C. After melting the low-density polyethylene in a torque rheometer, ethylene glycol diphenyl ether is added as an organic small molecule filler containing an electron-donating group, and the mass fraction of the filler is controlled at 0.1 - 3 wt%. During the blending process, the temperature is maintained at 110 - 120 °C, the rotation speed is controlled at 50 - 70 r / min, and the blending time is set at 10 - 30 min to ensure that the filler is evenly dispersed in the polymer matrix. Finally, an ethylene glycol diphenyl ether / low-density polyethylene composite material is obtained, and this material exhibits excellent nonlinear conductivity characteristics in a high electric field environment.

[0041] Example 2:

[0042] This example is basically the same as Example 1, except that the added organic small molecule filler with an electron-donating group is replaced with nonylphenol polyoxyethylene ether, and the mass fraction of the filler is also controlled at 1.0 wt%. The other process parameters such as the melting temperature, rotation speed, and blending time remain unchanged. Finally, a nonylphenol polyoxyethylene ether / low-density polyethylene composite material is obtained, and this material exhibits higher nonlinear conductivity characteristics in terms of electric field homogenization.

[0043] Example 3:

[0044] Compared with Example 2, the added organic small molecule filler with an electron-donating group in this example is replaced with allyloxy polyoxyethylene ether, and the mass fraction of the filler is still 1.0 wt%. Under the same melting temperature, blending rotation speed, and time conditions, the obtained allyloxy polyoxyethylene ether / low-density polyethylene composite material further improves the nonlinear conductivity characteristics of the material and exhibits excellent electric field homogenization ability.

[0045] Example 4:

[0046] Based on Example 3, in this example, the organic small molecule filler with an electron-donating group is replaced with octadecyl dimethyl hydroxyethyl ammonium nitrate, and the mass fraction of the filler is also 1.0 wt%. The other melting temperature, blending conditions, and time remain unchanged. The formed octadecyl dimethyl hydroxyethyl ammonium nitrate / low-density polyethylene composite material after blending has more excellent nonlinear conductivity characteristics and exhibits a higher electric field homogenization effect.

[0047] Control Example:

[0048] As a control material, in this embodiment, no organic small molecule filler containing an electron-donating group is added. Only low-density polyethylene (LDPE) is used as the matrix material, and processing is carried out according to the same melting temperature, blending rotation speed, and time. Since no small molecule filler with an electron-donating group is added, the control material does not exhibit obvious non-linear conductivity characteristics, and its electric field homogenization ability is also significantly lower than that of the composite materials prepared in each embodiment.

[0049] Performance comparison test:

[0050] To verify the performance of the materials in each embodiment, the current density-field strength relationship test, non-linear coefficient test, and LUMO energy level analysis are carried out on the prepared composite materials.

[0051] 1. Current density-field strength relationship:

[0052] The current density-field strength relationships of the materials in each embodiment and the control material are as Figure 1 shown. As the electric field strength increases, the current density of the materials in each embodiment gradually increases, and is significantly better than that of the control material without adding small molecule filler with an electron-donating group, indicating that the added small molecule with an electron-donating group effectively improves the non-linear conductivity characteristics of the composite material.

[0053] 2. Non-linear coefficient:

[0054] Further, the non-linear coefficient tests are carried out on the materials in each embodiment. As Figure 2 shown, the test results show that:

[0055] The non-linear coefficient of the material with ethylene glycol diphenyl ether filler reaches 6.5, which is 4.8% higher than that of the control material;

[0056] The non-linear coefficient of the material with nonylphenol polyoxyethylene ether filler is 7.0, an increase of 12.9%;

[0057] The non-linear coefficient of the material with allyloxy polyoxyethylene ether filler reaches 7.8, an increase of 30.6%;

[0058] The non-linear coefficient of the material with octadecyl dimethyl hydroxyethyl ammonium nitrate filler reaches 9.0, an increase of 50.0%.

[0059] 3. LUMO energy level analysis:

[0060] By carrying out the lowest unoccupied molecular orbital (LUMO) energy level analysis on the materials in each embodiment, as Figure 3 shown, the LUMO energy levels corresponding to different organic small molecule fillers with electron-donating groups are different. Among them, the LUMO energy level of the octadecyl dimethyl hydroxyethyl ammonium nitrate filler is the highest. Therefore, the non-linear conductivity characteristics of the material in this embodiment are the most excellent, showing the best electric field homogenization effect.

[0061] Through the test data analysis of each embodiment, it can be seen that organic small molecule fillers with different electron-donating groups have a significant impact on the non-linear conductivity characteristics of the composite material. Among them, the octadecyl dimethyl hydroxyethyl ammonium nitrate / low-density polyethylene composite material exhibits the best electric field homogenization effect and the highest non-linear coefficient, far superior to the control material without adding small molecules with electron-donating groups. By optimizing the types and addition amounts of small molecules with electron-donating groups, the all-organic non-linear insulating material provided by the present invention can be widely applied to high-voltage electrical equipment such as transformers, switchgear, and instrument transformers, providing a reliable technical guarantee for improving the insulation performance and service life of electrical equipment.

[0062] It should be noted that the above-described embodiments should be understood as illustrative and not limiting the protection scope of the present invention. The protection scope of the present invention is subject to the claims. For those skilled in the art, without departing from the essence and scope of the present invention, some non-essential improvements and adjustments made to the present invention still fall within the protection scope of the present invention.

Claims

1. An all-organic nonlinear insulating material based on an electron-donating group, characterized in that, Comprising: With polyolefin as the matrix; An organic small molecule containing an electron-donating group as a filler, and the mass fraction of the organic small molecule is 0.1 - 3 wt%.

2. The all-organic nonlinear insulating material according to claim 1, characterized in that, The polyolefin is any one of low-density polyethylene, high-density polyethylene or polypropylene.

3. The all-organic nonlinear insulating material according to claim 1 or 2, characterized in that, The organic small molecule is any one of ethylene glycol diphenyl ether, nonylphenol polyoxyethylene ether, allyloxy polyoxyethylene ether or octadecyl dimethyl hydroxyethyl ammonium nitrate.

4. A preparation method of an all-organic nonlinear insulating material based on an electron-donating group, characterized in that, Including the following steps: Placing the polyolefin matrix in a torque rheometer to melt; Adding an organic small molecule filler with a mass fraction of 0.1 - 3 wt%; Blending for 10 - 30 min under the conditions of a temperature of 110 - 120 °C and a rotation speed of 50 - 70 r / min to obtain an all-organic non-linear insulating material based on an electron-donating group.

5. The preparation method according to claim 4, characterized in that, The polyolefin matrix is any one of low-density polyethylene, high-density polyethylene or polypropylene.

6. The preparation method according to claim 4, characterized in that The organic small molecule is any one of ethylene glycol diphenyl ether, nonylphenol polyoxyethylene ether, allyloxy polyoxyethylene ether or octadecyl dimethyl hydroxyethyl ammonium nitrate.

7. The preparation method according to any one of claims 4-6, characterized in that, The blending temperature is 110 - 120 °C, the rotation speed is 50 - 70 r / min, and the time is 10 - 30 min.

8. Application of a fully organic non-linear insulating material based on an electron-donating group, characterized in that, The material is applied to high-voltage electrical equipment to homogenize the electric field distribution and improve the non-linear conductivity characteristics of the material.

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