Surface modification of EPDM rubber by microwave excited plasmas

Abstract

In the present work, a microwave excited plasma (2·45 GHz, 1 kW) was used to modify the surface characteristics of the ethylene propylene diene monomer rubber. The samples were treated with a mixture of nitrogen, hydrogen and argon plasmas. The operating gas pressure was in the 0·2–1 Torr range, the gas flowrate between 5 and 100 sccm and the treatment time varied from 10 to 600 s. The influence of the plasma treatment on the superficial characteristics of the samples was analysed by contact angle measurements and atomic force microscopy. The results show that the plasma treatment can promote an important decrease in the contact angle from 101° for untreated sample to 34° for samples treated in a mixture of H₂/N₂/Ar for 2 min, which corresponds an increase on the rubber surface adhesion work from 59 to 133 mJ m⁻².