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首页> 外文期刊>Journal of Applied Polymer Science >Formation and inhibition of free radicals in electrically stressed and aged insulating polymers
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Formation and inhibition of free radicals in electrically stressed and aged insulating polymers

机译：电应力和老化绝缘聚合物中自由基的形成和抑制

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Previous work has shown that prebreakdown, electrical aging, and breakdown phenomena are directly associated with charge carriers injected from electrical contacts and their subsequent dissociative trapping and recombination. In addition, the energy released from each trapping or recombination event is dissipated in the breaking of the bonds of macromolecules, thus forming free radicals and new traps in the electrically stressed insulating polymers, as predicted by Kao's model. It is this gradual degradation process that leads to electrical aging and destructive breakdown. New experimental results are presented to confirm previous findings and a new approach to inhibit the degradation process by the incorporation of suitable dopants into the polymer. The concentration of free radicals in the polymer increases with an increasing electric field at a fixed stress time of 250 h and with increasing stress time at a fixed electric field of 833 kV cm(-1). The concentration of free radicals is directly related to the concentration of new traps created by stress. However, when suitable dopants are incorporated, the initiation voltage for the occurrence of electrical treeing and the breakdown strength are both increased. The dopants tend to create shallow traps and have little effect on the deep trap concentration. This implies that the dopants act as free-radical scavengers that tend to satisfy the unpaired electrons of the broken bonds, which create new acceptor-like electron traps and new shallow traps. By doing so, the shallow traps screen the deep traps, thereby reducing the energy released during trapping and recombination and the probability of breaking the macromolecular bonds and causing structural degradation. (C) 2003 Wiley Periodicals, Inc. [References: 32]
机译：先前的工作表明，预击穿，电老化和击穿现象与从电触点注入的电荷载流子及其随后的解离俘获和复合直接相关。此外，从每个捕获或重组事件释放的能量都会随着大分子键的断裂而消散，从而如Kao模型所预测的那样，在电应力绝缘聚合物中形成自由基和新的陷阱。正是这种逐渐退化的过程导致了电老化和破坏性击穿。提出了新的实验结果以证实以前的发现，并提出了通过将合适的掺杂剂掺入聚合物来抑制降解过程的新方法。聚合物中自由基的浓度在250 h的固定应力时间下随着电场的增加而增加，在833 kV cm（-1）的固定电场下随着应力时间的增加而增加。自由基的浓度与应力产生的新陷阱的浓度直接相关。然而，当掺​​入合适的掺杂剂时，用于发生电树的起始电压和击穿强度均增加。掺杂剂倾向于产生浅陷阱，并且对深陷阱浓度影响很小。这暗示着掺杂剂充当自由基清除剂，其趋向于满足断裂键的未配对电子，从而产生新的类似受体的电子陷阱和新的浅陷阱。通过这样做，浅陷阱将深陷阱屏蔽，从而减少了在陷阱和复合过程中释放的能量以及破坏大分子键并导致结构退化的可能性。 （C）2003 Wiley Periodicals，Inc. [参考：32]

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