Preparation and anticorrosion performance of nano polyaniline/polyurethane interpenetrating network composite coating

Polyaniline−dodecylbenzene sulfonic acid (PANI-DBSA) particles were synthesized through in situ lotion polymerization of aniline and DBSA as raw materials, followed by combining with epoxy resin (E-44) and castor oil (CO) to prepare a PANI mixture (PANI-DBSA/CO) which was used as a nanofiller to create a nano polyaniline/polyurethane (PANI-PU) interpenetrating polymer network (IPN) coating. SEM, XRD and Fourier transform infrared spectroscopy were used to characterize the PANI-DBSA and PANI-PU IPN composite coatings that were produced. The coatings’ physical and mechanical characteristics were investigated, as well as the system's corrosion behaviour in 3.5 wt% NaCl solution, utilizing electrochemical impedance spectroscopy and electrokinetic polarization. Acid, alkali and saltwater immersion investigations were used to further evaluate the coatings’ medium resistance. The results show that when PANI-DBSA is added at 1 wt%, the contact angle reaches 102.6°, the adhesion reaches S1 grade after 720 h immersion, the tensile strength is 16.22 MPa and the elongation reaches 208%. The impedance value of the composite coating grew by 569 times with the addition of 1 wt% PANI, and the resistance duration to 10 wt% H₂SO₄, 10 wt% NaOH and 3.5 wt% NaCl reached more than 90 days. The addition of PANI to IPN coatings can increase corrosion resistance and extend their application range. © 2023 Society of Industrial Chemistry.