Effect of molecular weight of phenalkamines on the curing, mechanical, thermal and anticorrosive properties of epoxy based coatings

The present investigation deals with the study of effect of molecular weight and structures of phenalkamine curing agents on the curing, mechanical, thermal and anticorrosive properties of epoxy based coatings. The phenalkamines were prepared by varying the composition of formaldehyde and diamine in the formulation. The structural characterization confirmed successful preparation of high molecular weight phenalkamines. These were then used as curing agents for air drying and thermally curable epoxy coatings. The effect of these phenalkamines on curing properties of epoxy resin as well as mechanical, chemical, thermal and dynamic thermo-mechanical properties of the resultant coatings was studied and compared with commercial phenalkamine. The anticorrosive properties of the coatings were evaluated by salt spray test and electrochemical impedance spectroscopy. The study revealed that high molecular weight phenalkamines resulted in faster surface drying due to rapid molecular weight build-up. The anticorrosive performance also improved as indicated by higher modulus and electrochemical potential values.