Stable waterborne epoxy emulsions
The aim of a recent study was to prepare stable waterborne epoxy emulsions and study the properties of their corresponding coatings containing different contents of silica nanoparticles.
For this purpose and in the first step, the stabilising effect of various amounts of an acrylate terpolymer latex (poly (methyl methacrylate-co-butyl acrylate-co-acrylic acid)) and a non-ionic emulsifier (nonyl phenol ethoxylates 20 emulsifier (known as Kenon 20)) on waterborne epoxy emulsions was explored. The results indicated that the emulsion containing 5 wt.% latex and 6 wt.% Kenon 20 (EK6A5) was the most stable. In the next step, silica nanoparticles with 1, 2, 3, and 4 wt.% were added to EK6A5 emulsion. It was found that addition of nanoparticles up to 3 wt.% improved the stability.
Enhanced properties
Finally, the pure and nanoparticle contained emulsions were coated on a steel substrate and their adhesion performance, pencil hardness, surface wettability, and wear and corrosion resistance were investigated. The comparison between the samples with and without silica nanoparticles revealed enhanced properties such as adhesion strength, wear resistance, corrosion resistance, and increased contact angle by addition of proper amounts of silica nanoparticles (up to 3 wt.%).
The study has been published in Progress in Organic Coatings, Volume 156, July 2021.
