温度及湿度对不同应力模式下低密度聚乙烯薄膜电击穿强度的影响

Effect of Temperature and Humidity on Electrcal Breakdown Strength of Low-Density Polyethylene Film for Various Stressing Modes

本文讨论温度及湿度对不同应力模式下低密度聚乙烯(LDPE)薄膜电强度的影响。发现水分子既可作受主,俘获电子,又可作增塑剂,从而给高聚物的介电击穿特性带来复杂的影响。直流预应力愈高,注入到更深陷阱中的电荷就愈多。由于深陷阱中的电荷在直到70℃的温度范围内仅部分消失,因此反场下干样品的归一化脉冲击穿场强 E_(fo)/E_(ib)的恢复特性变慢甚至消失。这些推论可由热激及载流子输运测量证实。

The present paper discusses the effect of temperature and humidity on the ele- ctric strength of low-density polyethylene(LDPE)film for various stressing modes. We have found that the water molecule can act either as an acceptor or as a plasticizer,thus exerting a complicated influence on the dielectric breakdown in the polymers,The higher the direct prestressing,the more the charges are injected into deeper traps.Because the space charge,in deeper traps only partly disappears in the temperature range up to 70℃,the recovery of the normalized impulse bre- akdown strength E_(fo)/E_(ib)of dry specimens with field opposing becomes slow and even ceases.These inferences can be firmly supported by thermally stimulated current and charge carrier transport measurements.