Abstract
Corona discharge in air appreciably increased surface energies of ethylene—propylene—diene rubber (EPDM), a blend of chlorobutyl and natural rubbers, and styrene—butadiene rubber (SBR), as determined by contact angle measurements. High energy surfaces were typically short-lived, on the order of minutes, presumably due to facile reconstruction of the surface by mobile elastomer chains. Surface activation occurred despite the relatively thick specimens (1.8–2.5 mm) and the presence of up to 35% by weight of carbon black. Electrode configurations had an effect on the experimental results. Ozone, a byproduct of corona discharge, eroded the surface of SBR. Modest improvements in the bonding of an elastomeric urethane coating were realized with some of the surface-activated elastomers.