Performance of polyester/epoxy binder coating system – studies on coating resistance, adhesion and differential scanning calorimetry

Abstract

Purpose The purpose of this paper is to study the electrochemical, mechanical and thermal characteristics of polyester – epoxy coating systems using electrochemical impedance spectroscopy (EIS), pull-off test and differential scanning calorimetry (DSC). These are very important properties to evaluate the performance of a coating system. Proper measurement and analysis techniques are needed for a proper evaluation of these properties to ensure the coating performance. Design/methodology/approach Different ratios of polyester and epoxy resins have been blended to formulate good anticorrosive, mechanically strong and thermally stable binder coating system. EIS, pull-off test and DSC were used to evaluate these properties. Findings The sample containing 90 wt.% polyester exhibited the best corrosion resistance from the beginning until the end of exposure time. The value of corrosion resistance (Rc) obtained on the 30th day of exposure was found to be 2.89 × 108 ohm cm−2. The glass transition temperature (Tg) was found to be increasing with the incorporation of epoxy to the binder system. The result from pull-off test showed the best adhesion with the sample containing 90 wt.% polyester which also has the lowest Tg promoted better adhesion properties. Practical implications The curing time must be reduced for practical applications. Originality/value Hybrid coatings systems have been formulated. This paper discusses on the highest coating resistance obtained polymer-substrate mechanical properties and thermal characteristic of the polyester/epoxy binder resin using DSC.