Efficient Anticorrosion Coatings Based on Waste Tea Bags-Derived Nanocrystalline Cellulose-Incorporated Polyaniline Nanocomposites

Corrosion is an age-old global issue that demands advanced protection solutions, among which the nanostructured electroactive coatings are getting special attention. Herein, we demonstrated the utilization of waste tea bags as a source for producing nanocrystalline cellulose (NCC) that was further incorporated into the polyaniline (PANI) matrix to synthesize PANI/NCC composites via in situ polymerization of aniline with the addition of NCC dispersed phase. Subsequently, various anticorrosion compositions based on epoxy resin containing different proportions of PANI/NCC were formulated and coated over mild steel substrate. Their corrosion inhibition performance was measured through Tafel polarization curves and electrochemical impedance profiles under saline environment (3.5% NaCl electrolyte). It was observed that the mild steel coated with epoxy having 1.5 wt% loading of PANI/NCC composite showed significantly high corrosion inhibition efficiency (99%), which is ascribed to the combined effect of barrier action of NCC to corrodents (water/oxygen) as well as ennoblization by PANI.