Li Peng, Wang Xuan, Jin Jin, Sun Xiangxiang, Zhang Hui, Zhang Runsheng
Key Laboratory of Engineering Dielectrics and Its Application of Ministry of Education, Harbin University of Science and Technology, Harbin 150080, China.
Polymers (Basel). 2023 Dec 29;16(1):119. doi: 10.3390/polym16010119.
In this paper, a new multifunctional compound, 1,1'-(oxalylbis(4,1-phenylene))bis(1H-pyrrole-2,5-dione) (BVM), is grafted onto crosslinked polyethylene (XLPE) by radical-initiated grafting to play triple roles as a voltage stabilizer, space-charge inhibitor and crosslinking auxiliary and to achieve the purpose of comprehensively enhancing the DC dielectric properties of polymers while decreasing the type and number of additives. By analyzing the DC breakdown field strength, current density and space-charge distribution of the materials at different temperatures, it is demonstrated that BVM grafting can comprehensively and effectively enhance the electrical properties of the materials, with little dependence on temperature. The BVM molecule has two polar groups and an effective molecular structure that acts as a voltage stabilizer, thus enabling the introduction of dense, uniform, deeply trapped energy levels within the material to inhibit the space charge and to capture high-energy electrons to prevent damage to the material structure; however, the two functions do not affect each other. This is also consistent with first-principles calculations and quantum-chemical calculations. Gel content testing shows no effect on polymer crosslinking, even with a 27.8% reduction in the amount of the crosslinking agent di-isopropyl peroxide (DCP), which reduces the damage to the polymer's electrical resistance caused by the byproducts of DCP decomposition. Therefore, grafting multifunctional BVM compounds to improve the dielectric characteristics of polymers is a viable area of study in the development of high-voltage direct current (HVDC) cable materials.
在本文中，一种新型多功能化合物1,1'-(草酰双(4,1-亚苯基))双(1H-吡咯-2,5-二酮)(BVM)通过自由基引发接枝到交联聚乙烯(XLPE)上，发挥电压稳定剂、空间电荷抑制剂和交联助剂的三重作用，以达到在减少添加剂种类和数量的同时全面提高聚合物直流介电性能的目的。通过分析材料在不同温度下的直流击穿场强、电流密度和空间电荷分布，表明BVM接枝可以全面有效地提高材料的电学性能，且对温度依赖性较小。BVM分子具有两个极性基团和一个有效的分子结构，可作为电压稳定剂，从而能够在材料内部引入密集、均匀、深捕获的能级，以抑制空间电荷并捕获高能电子，防止材料结构受损；然而，这两种功能互不影响。这也与第一性原理计算和量子化学计算结果一致。凝胶含量测试表明，即使交联剂二异丙基过氧化物(DCP)的用量减少27.8%，对聚合物交联也没有影响，这减少了DCP分解副产物对聚合物电阻的损害。因此，接枝多功能BVM化合物以改善聚合物的介电特性是高压直流(HVDC)电缆材料开发中一个可行的研究领域。
