Castor oil-TiO2 hyperbranched poly (ester amide) nanocomposite: a sustainable, green precursor-based anticorrosive nanocomposite coatings

Abstract

In last decade study on anticorrosive performance of hyperbranched polymer nanocomposites attracted the overwhelming attention of researchers. However, scanty work on oleo hyperbranched polymer coatings are reported in the literature, while no work has been reported on castor oil-TiO2 nanoparticle dispersed hyperbranched poly (ester amide) nanocomposite coatings. Thus, herein we report the synthesis and performance of TiO2 nanoparticle dispersed hyperbranched poly (ester amide) nanocomposite coatings on Physico-mechanical and anticorrosive coatings on carbon steel in 3.5 wt. % HCl, NaCl and NaOH solutions. The synthesis of hyperbranched polymer is based on the simple A2+B3 polycondensation reaction. The structural elucidations of these were done using FTIR and NMR (1H and 13C) spectroscopy while the physico-mechanical tests were conducted by standard ASTM methods. The electrochemical corrosion techniques such as open circuit potential, potentiodynamic polarization, electrochemical impedance spectroscopy and salt spray tests were used to analyse the anticorrosive activity of these coatings. These studies revealed that the TiO2 dispersed hyperbranched poly (ester amide) coatings exhibit far superior physico-mechanical, hydrophobic (contact angle values from 98° to 107°) and anticorrosive properties (icorr 9.89 × 10−7 Acm-2, Ecorr -0.192 V, impedance ∼ 105 Ω cm2, phase angle 77° and Rpore 3.7 × 106) than those of hyperbranched poly (ester amide) and other such earlier reported coating systems.