Surface degradation of silicone rubber exposed to corona discharge

This paper describes the surface degradation of unfilled high-temperature vulcanized silicone rubber (HTV-SR) resulting from creeping corona discharges under atmospheric pressure. In this paper, HTV-SR specimens were exposed to corona stress generated by a parallel needle-plate electrode system; furthermore, physicochemical analyses were conducted on the surface layer of SR before and after corona discharge treatment. The results showed that the plasma impingement from the corona discharge can cause physical and chemical damages to the SR surface. In addition, it was demonstrated that instead of hydrophobic CH3 groups, hydrophilic OH groups that are by-products of aging may be formed on the surface of aged SR; furthermore, the corona discharge plays an important role in the loss of hydrophobicity.