Novel anti-corrosion coatings from rubber-modified polybenzoxazine-based polyaniline composites

In this work, the use of rubber-modified polybenzoxazine (PBZ) as the polymer matrix for the polyaniline emeraldine salt (PANI ES) filler was studied and demonstrated for the first time for its potential anti-corrosion application for carbon steel. PBZ was chosen as the main polymer component because of its outstanding properties such as near-zero shrinkage upon polymerization, low surface free energy, good dielectric, thermal, and mechanical properties, and most notably, its low water absorption ability. The concentration of the PANI ES was varied and the anti-corrosion property of varying loadings of PANI ES was tested. Results of the electrochemical measurements afterimmersion in chloride solution showed that the rubber-modified PBZ is able to protect the carbon steel from corrosion attack. On the other hand, the composites with different PANI ES concentrations were observed to be even more effective in protecting the carbon steel against corrosion. But when the immersion time was prolonged and results were compared, it was found that a low concentration of the PANI ES is needed to tune the anti-corrosion property of the coating to its optimum performance.