Method for evaluating ratio of modified hydrophobic insulating material based on magnesium oxide doped epoxy resin

Abstract

The invention discloses a method for evaluating the ratio of a modified hydrophobic insulating material based on magnesium oxide doped epoxy resin, which comprises the following steps of: preparing two groups of insulating materials of epoxy resin which is not doped with magnesium oxide nano-particles and doped with magnesium oxide nano-particles, and respectively measuring the contact angle and the water absorption rate of two groups of samples at room temperature; respectively calculating hydrophobicity evaluation factors of the two groups of samples before aging by using the data; then performing high-temperature accelerated aging treatment on the two groups of materials, measuring the contact angle and the water absorption rate of an aged sample, calculating a hydrophobicity evaluation factor after aging, and comprehensively considering the hydrophobicity evaluation factor before aging and the hydrophobicity evaluation factor after aging to obtain a hydrophobicity comprehensive evaluation factor of the modified epoxy resin insulating material; and further evaluating the accuracy of the ratio of the modified hydrophobic insulating material with the magnesium oxide doped with the epoxy resin. According to the method, the hydrophobicity comprehensive evaluation factor is utilized to evaluate the hydrophobicity of the modified epoxy resin, the accuracy of different raw material ratios of the modified epoxy resin can be quickly judged, and a basis is provided for selecting a proper magnesium oxide doped modified epoxy resin raw material ratio.

Description

Technical Field

[0001] The invention belongs to the field of electrical insulation protection of intelligent switch cabinets, and in particular relates to a method for evaluating the proportion of modified hydrophobic insulating materials based on magnesium oxide-doped epoxy resin. Technical Background

[0002] With the increasing scale of my country's power grid, the continuous improvement of voltage levels and the continuous adjustment of transmission lines, the entire power system has greatly increased the requirements for the stability and reliability of power equipment such as switchgear. The condensation problem is one of the main types of faults that affect the safe and stable operation of switchgear. Switchgear is very prone to condensation in a high humidity environment, which in turn causes serious damage to the insulating parts in the switchgear: the surface resistivity of the insulating parts decreases; the electric field on the surface of the insulating parts is distorted or even causes breakdown; the aging of the insulating materials is accelerated, causing their performance to deteriorate. There are reports of accidents caused by condensation affecting insulation performance in various parts of my country. Therefore, it is necessary to take adequate protective measures against the condensation problems faced by switchgear, to ensure the stable operation of the insulating materials used in the switchgear, and to improve the quality of power supply.

[0003] Epoxy resin (EP) has excellent electrical, thermal and mechanical properties and is the core material for insulating components of switch cabinets. Epoxy resin is hydrophilic, so its anti-condensation performance is poor. In order to improve the anti-condensation performance of epoxy resin for switch cabinets, a method of brushing moisture-proof paint on the surface of epoxy resin is usually adopted. However, this method has the disadvantages of requiring frequent replacement and cumbersome operation. By modifying the hydrophobic properties of the epoxy resin itself, the trouble of replacing the paint can be avoided, and it can be combined with other anti-condensation methods to minimize the impact of condensation. However, there is currently a lack of effective evaluation methods for whether the raw material ratio of modified hydrophobic epoxy resin is reasonable. Therefore, there is an urgent need for an evaluation method for the raw material ratio of modified hydrophobic epoxy resin. Summary of the invention

[0004] In view of the above technical problems, the purpose of the present invention is to propose a modified hydrophobic insulating material ratio evaluation method based on magnesium oxide doped epoxy resin, which can effectively evaluate the effects of different ratios of anhydride curing agent addition and magnesium oxide nanoparticle addition on the hydrophobicity of epoxy resin;

[0005] The technical solution for implementing the present invention is as follows:

[0006] Step 1: Prepare epoxy resin insulation material without magnesium oxide nanoparticles. By obtaining the commonly used acid anhydride curing agent addition amount δ (indicates that δ parts of curing agent are added per 100 parts of epoxy resin matrix), the maximum addition amount is recorded as δ max , the minimum addition amount is recorded as δ min , take 20 groups of evenly increasing anhydride curing agent addition amount δ i , where δ1=δmin , δ 20 =δ max ; Prepare n samples of epoxy resin insulation material with each amount of anhydride curing agent added, and measure the contact angle θ of the samples at room temperature T i0 and water absorption w i0 ;

[0007] Step 2: Prepare epoxy resin insulating material doped with magnesium oxide nanoparticles. By obtaining the commonly used acid anhydride curing agent addition amount δ (indicates that δ parts of curing agent are added per 100 parts of epoxy resin matrix), the maximum addition amount is recorded as δ max , the minimum addition amount is recorded as δ min , take 20 groups of evenly increasing anhydride curing agent addition amount δ i , where δ1=δ min , δ 20 =δ max ; Obtain the amount of magnesium oxide nanoparticles added β commonly used in modifying epoxy resin insulating materials on the market (indicates that β parts of magnesium oxide nanoparticles are added per 100 parts of epoxy resin matrix), and record the maximum addition amount as β max , the minimum addition amount is recorded as β min , take 20 groups of uniformly increased magnesium oxide nanoparticle addition amount β j , where β1 = β min , β 20 =β max ; Prepare n epoxy resin insulation material samples with different anhydride curing agent addition amounts and magnesium oxide nanoparticle addition amounts, and measure the contact angle θ of the samples at room temperature T ij and water absorption w ij ;

[0008] Step 3: Combine the data obtained from the first and second steps to calculate the hydrophobicity evaluation factor before aging using formula (1);

[0009]

[0010] Step 4: The samples of epoxy resin insulation material without magnesium oxide nanoparticles and epoxy resin insulation material doped with magnesium oxide nanoparticles were aged at temperatures of T k The accelerated aging treatment is carried out under the environment of (T1 = 2T, T2 = 4T, T3 = 6T), and the aging time is t k ; The epoxy resin insulation material samples after accelerated aging treatment were tested, and the contact angle and water absorption rate of the epoxy resin insulation material samples without magnesium oxide nanoparticles were recorded as θ i0(k) and w i0(k) , the contact angle and water absorption rate of the epoxy resin insulation material sample doped with magnesium oxide nanoparticles are recorded as θij(k) and w ij(k) ; Calculate the hydrophobicity evaluation factor after aging by formula (2);

[0011]

[0012] Step 5: Calculate the comprehensive evaluation factor of hydrophobicity of magnesium oxide-doped modified epoxy resin insulation material using formula (3);

[0013]

[0014] Step 6: Further evaluate the accuracy of the ratio of the modified hydrophobic insulating material of magnesium oxide doped epoxy resin based on the comprehensive hydrophobicity evaluation factor;

[0015] According to formula (3), the accuracy of the ratio of the modified hydrophobic insulating material doped with magnesium oxide epoxy resin is evaluated. If 0<γ≤0.9, it means that the epoxy resin insulating material prepared with the corresponding ratio has good hydrophobicity. If 0.9<γ≤1.2, it means that the epoxy resin insulating material prepared with the corresponding ratio has average hydrophobicity. If γ>1.2, it means that the epoxy resin insulating material prepared with the corresponding ratio has poor hydrophobicity.

[0016] The beneficial effect of the present invention lies in that, by preparing two groups of insulating materials, epoxy resin without magnesium oxide nanoparticles and epoxy resin doped with magnesium oxide nanoparticles, and measuring the contact angle and water absorption rate of the two groups of samples before and after aging, the two parameters of the hydrophobicity evaluation factor before aging and the hydrophobicity evaluation factor after aging are integrated, and a modified hydrophobic insulating material ratio evaluation method based on magnesium oxide doped epoxy resin is provided, which can effectively calculate the comprehensive hydrophobicity evaluation factor, and provides a way to select a suitable ratio of raw materials for doped magnesium oxide modified epoxy resin. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It shows a flow chart of a method for evaluating the proportion of modified hydrophobic insulating materials based on magnesium oxide doped epoxy resin. DETAILED DESCRIPTION

[0018] The present invention will be further described below in conjunction with the accompanying drawings and specific implementation processes.

[0019] Step 1: Prepare epoxy resin insulation material without magnesium oxide nanoparticles. By obtaining the commonly used acid anhydride curing agent addition amount δ (indicates that δ parts of curing agent are added per 100 parts of epoxy resin matrix), the maximum addition amount is recorded as δ max , the minimum addition amount is recorded as δ min , take 20 groups of evenly increasing anhydride curing agent addition amount δ i , where δ1=δ min , δ 20 =δmax ; Prepare n samples of epoxy resin insulation material with each amount of anhydride curing agent added, and measure the contact angle θ of the samples at room temperature T i0 and water absorption w i0 ;

[0020] Step 2: Prepare epoxy resin insulating material doped with magnesium oxide nanoparticles. By obtaining the commonly used acid anhydride curing agent addition amount δ (indicates that δ parts of curing agent are added per 100 parts of epoxy resin matrix), the maximum addition amount is recorded as δ max , the minimum addition amount is recorded as δ min , take 20 groups of evenly increasing anhydride curing agent addition amount δ i , where δ1=δ min , δ 20 =δ max ; Obtain the amount of magnesium oxide nanoparticles added β commonly used in modifying epoxy resin insulating materials on the market (indicates that β parts of magnesium oxide nanoparticles are added per 100 parts of epoxy resin matrix), and record the maximum addition amount as β max , the minimum addition amount is recorded as β min , take 20 groups of uniformly increased magnesium oxide nanoparticle addition amount β j , where β1 = β min , β 20 =β max ; Prepare n epoxy resin insulation material samples with different anhydride curing agent addition amounts and magnesium oxide nanoparticle addition amounts, and measure the contact angle θ of the samples at room temperature T ij and water absorption w ij ;

[0021] Step 3: Combine the data obtained from the first and second steps to calculate the hydrophobicity evaluation factor before aging using formula (1);

[0022]

[0023] Step 4: The samples of epoxy resin insulation material without magnesium oxide nanoparticles and epoxy resin insulation material doped with magnesium oxide nanoparticles were aged at temperatures of T k The accelerated aging treatment is carried out under the environment of (T1 = 2T, T2 = 4T, T3 = 6T), and the aging time is t k ; The epoxy resin insulation material samples after accelerated aging treatment were tested, and the contact angle and water absorption rate of the epoxy resin insulation material samples without magnesium oxide nanoparticles were recorded as θ i0(k) and w i0(k) , the contact angle and water absorption rate of the epoxy resin insulation material sample doped with magnesium oxide nanoparticles are recorded as θ ij(k) and w ij(k); Calculate the hydrophobicity evaluation factor after aging by formula (2);

[0024]

[0025] Step 5: Calculate the comprehensive evaluation factor of hydrophobicity of magnesium oxide-doped modified epoxy resin insulation material using formula (3);

[0026]

[0027] Step 6: Further evaluate the accuracy of the ratio of the modified hydrophobic insulating material of magnesium oxide doped epoxy resin based on the comprehensive hydrophobicity evaluation factor;

[0028] According to formula (3), the accuracy of the ratio of modified hydrophobic insulating material of magnesium oxide doped epoxy resin is evaluated.

Claims

1. A method for evaluating the proportion of modified hydrophobic insulating materials based on magnesium oxide doped epoxy resin. It is characterized in that The following steps are involved: Step 1: Prepare epoxy resin insulation material without magnesium oxide nanoparticles. By obtaining the commonly used acid anhydride curing agent addition amount δ (indicates that δ parts of curing agent are added per 100 parts of epoxy resin matrix), the maximum addition amount is recorded as δ max , the minimum addition amount is recorded as δ min , take 20 groups of evenly increasing anhydride curing agent addition amount δ i , where δ 1 =δ min , δ 20 =δ max ; Prepare n samples of epoxy resin insulation material with each amount of anhydride curing agent added, and measure the contact angle θ of the samples at room temperature T i0 and water absorption w i0 ; Step 2: Prepare epoxy resin insulating material doped with magnesium oxide nanoparticles. By obtaining the commonly used anhydride curing agent addition amount δ on the market (indicates that δ parts of curing agent are added per 100 parts of epoxy resin matrix), the maximum addition amount is recorded as δ max , the minimum addition amount is recorded as δ min , take 20 groups of evenly increasing anhydride curing agent addition amount δ i , where δ 1 =δ min , δ 20 =δ max ; Obtain the amount of magnesium oxide nanoparticles added β commonly used in modifying epoxy resin insulating materials on the market (indicates that β parts of magnesium oxide nanoparticles are added per 100 parts of epoxy resin matrix), and record the maximum addition amount as β max , the minimum addition amount is recorded as β min , take 20 groups of uniformly increased magnesium oxide nanoparticle addition amount β j , where β 1 =β min , β 20 =β max ; Prepare n epoxy resin insulation material samples with different anhydride curing agent addition amounts and magnesium oxide nanoparticle addition amounts, and measure the contact angle θ of the samples at room temperature T ij and water absorption w ij ; Step 3: Combine the data obtained from the first and second steps to calculate the hydrophobicity evaluation factor before aging using formula (1); Step 4: The samples of epoxy resin insulation material without magnesium oxide nanoparticles and epoxy resin insulation material doped with magnesium oxide nanoparticles were aged at temperatures of T k (T 1 =2T,T 2 =4T,T 3 =6T) environment, the aging time is t k ; The epoxy resin insulation material samples after accelerated aging treatment were tested, and the contact angle and water absorption rate of the epoxy resin insulation material samples without magnesium oxide nanoparticles were recorded as θ i0(k) and w i0(k) , the contact angle and water absorption rate of the epoxy resin insulation material sample doped with magnesium oxide nanoparticles are recorded as θ ij(k) and w ij(k) ; Calculate the hydrophobicity evaluation factor after aging by formula (2); Step 5: Calculate the comprehensive evaluation factor of hydrophobicity of magnesium oxide-doped modified epoxy resin insulation material using formula (3); Step 6: Further evaluate the accuracy of the ratio of the modified hydrophobic insulating material of magnesium oxide doped epoxy resin based on the comprehensive hydrophobicity evaluation factor; According to formula (3), the accuracy of the ratio of the modified hydrophobic insulating material doped with magnesium oxide epoxy resin is evaluated. If 0<γ≤0.9, it means that the epoxy resin insulating material prepared with the corresponding ratio has good hydrophobicity. If 0.9<γ≤1.2, it means that the epoxy resin insulating material prepared with the corresponding ratio has average hydrophobicity. If γ>1.2, it means that the epoxy resin insulating material prepared with the corresponding ratio has poor hydrophobicity.

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