Delocalized aromatic molecules with matched electron‐donating and electron‐withdrawing groups enhancing insulating performance of polyethylene blends

J of Applied Polymer Sci

Zhu

et al. 2022

Self Cite

The effect of adding electron-buffering voltage stabilizer (1 wt% maminobenzoic acid) on the electrical tree-induced degradation of cross-linked polyethylene (XLPE) was studied at high temperatures. The electrical tree inception, growth, and partial discharge characteristics were simultaneously analyzed at 30, 50, and 70 C, respectively. The results showed that the growth rate of electrical tree and partial discharge activity as well as the discharge repetition rate, significantly increased with the temperature for pure XLPE and XLPE stabilizer blend. However, the XLPE stabilizer blend exhibited higher tree inception voltage, lower tree growth rate, and partial discharge activity than pure XLPE. The addition of the voltage stabilizer reduced the carbon layer thickness in the tree channel and offered higher resistance to the electrical tree growth. Surface potential decay demonstrated that the voltage stabilizer addition decreased the trap energy level, but increased the shallow trap density of the XLPE. Quantum chemical calculations showed that the voltage stabilizer enhanced the ability to buffer the high-energy electrons in the XLPE. A high-energy electron buffering mechanism was also proposed to explain the effect of voltage stabilizer on the electrical treeing and partial discharge activity in the XLPE at high temperatures.

Section: Discussionmentioning

confidence: 99%

Section: Sample Preparationmentioning

confidence: 99%

Section: Influence Of the Temperature On Electrical Treeing And Parti...mentioning

confidence: 99%

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Inhibition of electrical trees degradation of crosslinked polyethylene at high temperatures by electron‐buffering voltage stabilizers

Hong

J of Applied Polymer Sci

Zhu

et al. 2022

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“…Koopman's theorem states that vertical electron affinity is approximately equal to -LUMO (i.e., a negative value of LUMO). 16 All three-voltage stabilizers possess positive electron affinity energy. A significant number of electrons will have difficulty obtaining sufficient kinetic energy to cause collision ionization, usually regarded as the initial condition for the electron avalanche effect.…”

Section: Quantum Chemical Calculationbased Analysismentioning

confidence: 99%

Influence of organic additives with electron‐withdrawing and electron‐donating groups on insulation properties of cross‐linked polyethylene at high temperatures for HVDC cable applications

Shi

J of Applied Polymer Sci

Meng

et al. 2022

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This paper investigated the influence of three aromatic voltage stabilizers (4-npropylbenzoic acid, 2-methoxyphenylboronic acid, and 3-aminobenzoylmethylamide) on insulating properties of cross-linked polyethylene (XLPE) at high temperatures for high voltage direct current (HVDC) applications. The XLPE blends containing 1 wt% voltage stabilizers were prepared through a solution-blending method. The addition of voltage stabilizers suppressed the space charge inside the XLPE at high temperatures. The DC conductivity of XLPE and its blends increased with temperature. The DC conductivity of the XLPE blended with the 4-n-propylbenzoic acid was lowest at the different temperatures and electric fields. The DC breakdown strength of the tested materials continually decreased as the temperature increased. Notably, the DC breakdown strength of XLPE with the addition of 4-n-propylbenzoic acid and 3-aminobenzoylmethylamide was higher than the reference XLPE at high temperatures. Moreover, the thermal stability of the XLPE remained unaffected after the voltage stabilizer's addition, whereas the thermal conductivity was improved. Quantum chemical calculations showed that the addition of voltage stabilizers with lower LUMO could effectively buffer the high-energy electrons and improve the DC breakdown strength of the XLPE. A buffering mechanism of high-energy electrons demonstrated the effect of the voltage stabilizers on the DC breakdown strength in the XLPE.

“…Moreover, its conjugated π system can be excited by high-energy electrons, thereby absorbing electrons’ kinetic energy, which would otherwise endanger the polymer integrity. The addition of m -aminobenzoic acid as a voltage stabilizer effectively decreases the electrical conductivity, inhibits space charge accumulation, and increases tree initiation voltage of a low-density polyethylene and high-density polyethylene (LDPE/HDPE) blend …”

Section: Introductionmentioning

confidence: 99%

Enhancement of Insulation Properties of Cross-Linked Polyethylene Utilizing Aromatic Voltage Stabilizers with Electron-Withdrawing and Electron-Donating Groups

Shi

ACS Appl. Polym. Mater.

Meng

et al. 2022

Self Cite

This paper presents the influence of three different voltage stabilizers, 4-n-propylbenzoic acid, 2-methoxyphenylboronic acid, and 3-aminobenzoylmethylamide, on the insulation properties of cross-linked polyethylene (XLPE). The 1 wt % voltage stabilizers are blended with XLPE by a solution method, and then the samples are prepared via a hot pressing method. Electrical and physicochemical properties of the XLPE blends are analyzed by space charge, DC resistivity, DC breakdown strength, thermally stimulated depolarization current, Fourier transform infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry experiments. It is found that the addition of the voltage stabilizers enhances the DC resistivity and DC breakdown strength of the XLPE, which also inhibits the accumulation of space charges in the XLPE. The results show that the XLPE blend with the addition of 4-n-propylbenzoic acid has the lowest conduction current and a 23.3% increment in the DC breakdown strength compared to that of the reference XLPE among the used voltage stabilizers. Moreover, it is found that the melting properties and thermal stability of the XLPE are not affected by the addition of the voltage stabilizers. The XLPE blend with 4-n-propylbenzoic acid exhibits a uniform trap depth distribution, which facilitates the migration of the space charge to the anode and reduces the electric field inside the sample bulk. Quantum chemical calculations demonstrate that the matching ability of the electron-withdrawing and electron-donating groups of the three voltage stabilizers effectively enhances the electrical properties of the XLPE. In contrast, the 4-n-propylbenzoic acid has the lowest unoccupied molecular orbital energy level, which can effectively buffer the high-energy electrons and increase the DC breakdown strength. A charge carrier transport mechanism is also proposed to explain the effect of the voltage stabilizer on the space charge movement in the tested samples.