Design, synthesis, and evaluation of high‐performing anticorrosive polyurethane coatings with inbuilt redoxable oligomeric aniline segments

This paper presents, a facile route for the synthesis of electroactive hybrid polyurethane‐urea's (EPUU) using back‐bone modification with diamine‐capped trianiline (DCTA) and diamine‐capped tetraaniline (DCTAni) oligomers. These EPUUs were loaded with different weight percentages (12.5, 25, and 50) of DCTA and DCTAni and named PU‐DCTA (12.5, 25, and 50) and PU‐DCTAni (12.5, 25, and 50), respectively. The formation of oligomers and their EPUUs were confirmed by using formal characterizations such as FTIR, HRMS, UV–Visible spectroscopies, and electrochemical studies. TGA, DSC, and tensile studies were conducted on the cured films to better understand the structure and property relations. The mechanical and thermal properties of EPUU films are as high as 60.0 MPa tensile strength and T 5% at 322°C, and the adhesion strength of 300‐μm films on mild steel was observed as 533 psi. Tafel polarization and electrochemical impedance spectroscopy (EIS) measurements were used to determine these polymers' anti‐corrosive capabilities. An accelerated salt‐spray test that revealed the coatings are stable for up to 600 h when exposed to 5% NaCl fog. The high corrosion resistance observed for PU‐DCTAni was found to be 6.874 × 10 −6 mm/year from the Tafel polarization test, and its high polarization resistance was found to be up to 55.912 MΩ.