ROLE OF PROMOTERS IN IMPROVING ADHESION OF ORGANIC COATINGS TO A SUBSTRATE

An organic coating used as a protective layer is expected to withstand the widely varying environmental conditions which cause changes in it s structure and eventually lead to its failure in service. Among the p rime properties, adhesion - the interfacial force, which depends on pe netration of the coating phase into the micropores or crevices or surf ace irregularities of the substrate, forms a mechanical interlocking. It may fail due to the degradation of the binder, or the stress and st rain developed during application, curing and prolonged exposure. The science of adhesion has been studied extensively and the interfacial m olecular forces involved in this phenomenon are discussed. The formati on of a chemical bond linkage between an organic coating and a non-org anic surface, the role of coupling agents as adhesion promoters, the p henomena involved and the findings of earlier workers are summarized i n this review.