Effect of cobalt additives and mixed metal sulfides at rubber–brass interface on rubber adhesion: a computational study

Abstract

Interaction of rubber models with dopant atoms on ZnS(110) and Cu2S(111) surfaces, present in rubber–brass adhesive interlayer, has been studied via computational approach using density functional theory. Carbon–carbon double bonds and thiol groups in rubber are generally responsible of the interaction with metal atoms of ZnS(110) and Cu2S(111) surfaces. Inclusion of a copper atom into a zinc sulfide environment weakens the interaction with rubber. The incorporation of cobalt atoms as additives on ZnS(110) and Cu2S(111) surfaces enhances the adsorption strength with rubber. The cobalt dopant increases the adsorption strength of all functional groups of rubber with zinc sulfide, while in doped copper sulfide only the carbon–carbon double bond interaction with rubber is enhanced. It is noteworthy that also the adsorption of saturated hydrocarbons on zinc sulfide is improved by cobalt doping indicating enhanced carbon–hydrogen bond interaction with the sulfide surface.