From white pollution to green coating—PS/PANI anti-corrosive coatings from waste PS foams

Polystyrene (PS) foam is a major component of "white pollution", which has become a global environmental issue. How to solve the problem of white pollution has caused extensive research all around the world. In this paper, a simple way to transform waste polystyrene foam into green anti-corrosion coating was proposed through a seed polymerization method of polyaniline (PANI). PS foam was dissolved in aniline and ethyl acetate solution, afterwards PANI seeds and ammonium persulfate (APS) was added in, then the polymerization was initiated to form PS/PANI composites which could be used as the anti-corrosive coating. The physical properties and anti-corrosion performance of the coatings were detailed discussed. According to electrochemical impedance spectroscopy (EIS) results, the PS/PANI coatings have great corrosion resistance. When the mass percentage of aniline to PS was 30 % in the synthesis process, the protection efficiency of the products reached 99.99 % and the polarization resistance reached 6.524 × 106 Ω in 3.5 wt% NaCl solutions. Under the same condition, the charge transfer resistance was 2.81 × 103 Ω. In a word, this paper provides a new route for recycling wasted polystyrene foam. The wasted PS foams known as "white pollution" were used as a main raw material for production of "green anti-corrosion coatings". This simple processing method is in line with the sustainable development strategy and economic system construction.