Barrier properties of “epoxy resin - amine hardener” film-forming systems

Abstract

The article examines the physicomechanical and barrier properties of non-pigmented epoxy coatings formed from various film-forming systems based on epoxy resins and amine hardeners. The barrier properties of the coatings were evaluated by the nature of the frequency dependencies of the capacitance and resistance of the painted metal plates in contact with a 3 % aqueous solution of sodium chloride, and also by the magnitude of the displacement of the open circuit potential of the painted electrode compared to unpainted. It was experimentally established that a higher content of gel fraction is observed for coatings formed from low-viscosity film-forming compositions. It is shown that the physicomechanical and protective properties of epoxy coatings depend on the content of the functional groups in the epoxy resin and the nature of the amine hardener. It was found that to obtain coatings with better properties, it is preferable to use amine hardeners characterized by a low content of amine groups and a reduced proportion of secondary amino groups. A relationship was found between the protective properties of coatings and their water absorption. It is proposed to use the characteristics of water absorption of coatings as a simple method for assessing their barrier properties. The technological aspects of the use of the studied film-forming systems in the production of anticorrosive paints are considered. The advantages of using low viscosity epoxy film-forming systems without inert solvents are shown.