Partial replacement of metallic zinc dust in heavy duty protective coatings by conducting polymer

The aim of this work is to show that the high concentration of metallic zinc dust typically used in marine epoxy primers may be reduced by introducing a small concentration of conducting polymer as auxiliary anticorrosive additive. Specifically, in this work we compare the protection imparted by an epoxy coating with 79 wt.% of anticorrosive pigment with that obtained using the same formulation but reducing such concentration to 60 wt.% and adding 0.3 wt.% of polyaniline emeraldine salt. Initially, the influence of this modification in the structural, thermal and mechanical properties of the coating has been examined. After this, accelerated corrosion assays in an aggressive solution medium have been developed. The protection imparted by the unmodified and modified paint formulations has been determined using the standard method ASTM D 1654-79.