Study of interfacial chemistry on direct curing adhesion between Ni–P plating and rubber using 1,3,5‐triazine‐2,4,6‐trithiol monosodium salt

Direct adhesion between Ni–P‐plated iron and acrylonitrile–butadiene rubber, hydrogenated acrylonitrile–butadiene rubber and ethylene–propylene rubber was successful using 1,3,5‐triazine‐2,4,6‐trithiol monosodium salt (TTN) without any adhesive. Peel strength in the adherends was influenced by the amount of TTN employed. The interfacial structure between Ni–P‐plated iron and curing rubbers has been investigated with x‐ray microanalysis, x‐ray photoelectron spectroscopy and scanning electron microscopy. The TTN derivatives gathered locally at the interface between the Ni–P‐plated iron and curing rubber adherends. The TTN layer located near the interface is referred to as a reinforcement layer. This layer was in general ～70 nm thick and consisted of composites of the Ni salt of TTN. The TTN is thought to work as a binder that bonds between Ni–P‐plated iron and rubber chains. The single bonds between both Ni–P‐plated iron and rubber TTN was confirmed from Kraus plots and model experiments using TTN. Copyright © 2003 John Wiley & Sons, Ltd.