Influence of friction on the surface characteristics of EPDM elastomers with different carbon black contents

Tribological properties and surface characteristics of ethylene–propylene-diene elastomers were studied as a function of carbon black (CB) content. The surface analysis was performed inside and outside the wear track by X-ray photoelectron spectroscopy (XPS) in order to evaluate possible compositional changes produced by rubbing. Carbon black content had only a small influence on the surface chemistry of the unworn surfaces. However, on the surfaces subjected to friction, the oxygen concentration decreased with increasing CB content. Neither the surface analysis by XPS nor the wettability tests revealed important thermal degradation of the polymer in these friction tests.