Chitosan-polyaniline-TiO₂ ternary nanocomposite coating as effective anti-corrosion material for low carbon steel in 3.5 wt% NaCl solution

Abstract

The coating materials Polyaniline (PANi), Polyaniline-TiO_2, and Chitosan-Polyaniline-TiO₂ ternary nanocomposite (CPT) were separately synthesized by chemical oxidative polymerization with ammonium persulphate as an oxidant in a hydrochloride aqueous medium. The synthesized materials were characterized by FT-IR, XRD, SEM, and TEM. The FT-IR and XRD result adequately established the interaction between chitosan, PANi, and TiO₂ NPs. Microstructural studies revealed significant variation in the morphologies of PANi, PANi-TiO₂, and chitosan-polyaniline-TiO₂ nanocomposite and embedment of TiO₂ NPs in the polymer matrix. The coating materials PANi, PANi-TiO_2, and CPT were mixed with epoxy resin (10%) and subsequently, cast on low carbon steel (LCS) using NMP as solvent and triethyl tetra amine as curing agent. The anti-corrosion properties of coated specimens in 3.5 wt.% NaCl solution was evaluated using EIS studies, PDP, Salt spray test, water uptake test, immersion test, and SEM. Results of corrosion tests revealed superior corrosion protection offered by CPT ternary nanocomposite coating to LCS in 3.5 wt % NaCl solution compared to PANi and PANi-TiO₂ nanocomposite coatings.

Keywords:

• Conducting polymer
• steel
• nanocomposite coating
• corrosion studies

Acknowledgments

Farina Ansar, one of the authors, would like to thank the supervisor, the Chairman of Applied Chemistry, as well as UGC for their financial assistance. I’m also grateful for the USIF-AMU, Aligarh’s SEM, and TEM facilities.