Acetylated SEBS Enhanced DC Insulation Performances of Polyethylene

Abstract

Acetophenone can significantly improve the dielectric properties of polyethylene (PE) insulation materials. However, it easily migrates from the PE due to its poor compatibility with the material, which limits its application. In this paper, the functional units of acetophenone were modified in polystyrene-b-poly(ethylene-co-butylene)-b-polystyrene (SEBS) by an acetylation reaction, and SEBS was used as the carrier to inhibit the migration of acetophenone. The number of functional units in the acetylated SEBS (Ac-SEBS) was measured by 1H NMR and the effect of the acetylation degree of SEBS on its compatibility with PE was studied. Meanwhile, the effects of Ac-SEBS on PE’s direct current (DC) breakdown strength and space charge accumulation characteristics were investigated. It is demonstrated that Ac-SEBS can significantly improve the field strength of the DC breakdown and inhibit the accumulation of space charge in the PE matrix. This work provides a new approach for the application of aromatic compounds as voltage stabilizers in DC insulation cable materials.

Effect of Acetylated SEBS/PP for Potential HVAC Cable Insulation

“…The absorption peak located at 1269 cm −1 may derive from the vibration of the aromatic ketone skeleton. The absorption peak located at 826 cm −1 identifies the para substitution of the benzene ring for the C-H surface bending vibration [ 35 ]. Therefore, the IR spectrograms can prove that the acetophenone structural unit is constructed at the end of the benzene ring of Ac-SEBS.…”

“…The two absorption peaks adjacent to the carbonyl group on the benzene ring migrate to the lower field so that region C can be observed on the 1 H NMR spectra of Ac-SEBS. Region D (2.4–2.6 ppm) represents the proton peak of the methyl group on the acetophenone structural unit produced by the acetylation of SEBS [ 35 ]. The area of the resonance peak in the 1 H NMR spectrum is proportional to the number of protons producing this peak, so the degree of acetylation of Ac-SEBS can be calculated based on the area ratio of region A to region D. The degree of acetylation of the sample could be calculated by Equation (1): where Sub is the degree of acetylation of Ac-SEBS, A A is the proton peak area of A, and A D is the proton peak area of D.…”

Effect of Acetylated SEBS/PP for Potential HVDC Cable Insulation

“…Compared with SEBS, Ac-SEBS showed new absorption peaks at 1684, 1269, and 826 cm −1 . The absorption peak at 1684 cm −1 represents the C=O stretching vibration, the absorption peak at 1269 cm −1 represents the vibration of the aromatic ketone skeleton, and the weak absorption peak at 826 cm −1 represents the para substitution of the benzene ring for the C-H surface bending vibration [32]. Therefore, the infrared spectrum can prove that the acetyl group successfully grafted to the para position of the benzene ring in the polystyrene block of SEBS after the acetylation reaction and the acetophenone structural unit is present on Ac-SEBS.…”

“…The number of protons represented by region A does not change with the acetylation of SEBS, while the number of protons represented by region D increases with the increase of the degree of acetylation. Therefore, the acetylation degree of SEBS can be calculated by the ratio of the area of peak A to the area of peak D [32]. The acetylation degree of the samples could be calculated by Equation (1):…”

“…increase of the degree of acetylation. Therefore, the acetylation degree of SEBS can be culated by the ratio of the area of peak A to the area of peak D [32]. The acetylation deg of the samples could be calculated by Equation (1):…”