Studies on corrosion resistant properties of inhibitive primed IPN coating systems in comparison with epoxy-PU systems

Though blending polymers to obtain high performance materials is an old practice, the new trend in such an approach is the emergence of interpenetrating polymer networks (IPNs) as binders for protective coatings with improved properties. In this study, one ambient curing IPN-type polymer alloy developed out of epoxy and acrylic polyurethane systems as a high performing binder was formulated into paints and evaluated in comparison with the currently used conventional epoxy polyamide and polyurethane systems. A three-coat system consisting of a zinc phosphate primer, a micaceous iron oxide (MIO) undercoat, and a topcoat was formulated out of the IPN along with a similar system of epoxy primer, epoxy undercoat, and a PU topcoat. A two-coat system of the same primer with an IPN clear topcoat and a similar system with epoxy has also been studied. All the systems were studied under accelerated laboratory tests and field tests at a corrosive location. The results are reported and conclusions are drawn in this article.