Hybrid Epoxy-Polyurethane Coatings for Improved Corrosion Protection of Aluminium

A polymeric matrix consisting of epoxy resin and epoxidized soy bean oil (ESO) was prepared at the ratio of 90:10 to increase the anti-corrosion properties of epoxy. Water based epoxy and solvent based epoxy were used in this study for comparative study. Acrylic polyol was blended with the prepared epoxy/ESO and it was cured by using aliphatic polyisocyanate (NCO) to produce a hybrid of epoxy-polyurethane. The hybrid coating systems were prepared in different weight ratios of epoxy and polyurethane and were applied on aluminium panels. The thicknesses of the coatings were maintained around 90 to 110 mu m. After curing, the coatings were characterized by using electrochemical impedance spectroscopy (EIS) to study its barrier characteristics and its performance against corrosion. Further test such as pencil hardness test, cross hatch test and pull-off test was run to study the adhesion of the coatings.