ポリエチレンの放電劣化に対する放電生成気体の効果
1977 年 46 巻 3 号 p. 224-229
詳細
1977 年 46 巻 3 号 p. 224-229
The oxidation of polyethylene by partial discharge is supposed to proceed by two main processes: the vaporization of the sample film by activated oxygen (e. g. atomic oxygen) resulting in a decrease in weight, and a rather moderate oxidation by ozone resulting in an increase in weight. The ozone is formed by the reaction of molecular oxygen with the activated oxygen atom which is produced by partial discharge in air. The process mentioned above was examined by the flow method.
The polyethylene film near the point of the partial discharge in air was consumed by the activated oxygen, and on the other hand, the film remote from the discharging point exhibited a weight increase. The results showed the validity of the two processes mentioned above.
The concentration of activated oxygen decayed exponentially with time, the life time being about 0.1 sec at 7 Torr and inversely proportional to the ambient pressure. The life time at atmospheric pressure in air was extrapolated to be 1 msec approximately. The reaction rate of polyethylene with the activated oxygen is about one-hundred times greater than that with ozone. From the pressure dependence of the life time of the activated oxygen, it is suggested that a two-body collision process is predominant in the formation of the ozone.
