Surface characterization of silicone polymer used as an outdoor insulator by the measurement of surface voltage decay

In this paper, the surface states of silicone rubber based on polydimethylsiloxane used as an outdoor insulator and treated by ultraviolet (UV) irradiation and corona discharge were investigated by measuring the surface voltage decay of a corona-charged specimen. The surface resistivity determined by surface voltage decay was compared with a value obtained from the three-electrode method. Good agreement between the two methods for surface resistivity was obtained. Ultraviolet-treated specimens showed a slower decrease of surface voltage decay, whereas the corona-treated specimens showed a dramatically faster decrease. Although both artificial treatments led to the same oxidative products, which was confirmed with x-ray photoelectron spectroscopy (XPS), we could distinguish the difference between the reactions of the two treatments by monitoring the decay of the surface voltage on corona-charged specimens. In addition, we could derive the specific surface states of the silicone polymer that is treated by accelerated artificial aging factors and the degradation process. Copyright (C) 2002 John Wiley Sons, Ltd.