In situ synthesis of high-performance 4,4′-diaminodiphenylsulfone modified oleo-alkyd nanocomposite coatings: role of hybrid nanofillers on physico-mechanical, hydrophobic and corrosion protective performance

Abstract

Tung oil monoglyceride (TMG), 4,4′-diaminodiphenylsulfone modified (DDS-TO-alkyd) polypyrrole enveloped cerium oxide (PPy-PSCeO₂) nanofiller dispersed alkyd nanocomposites (alk-DDS-PPy-PSCeO₂-x) were synthesized using pyromellitic dianhydride through an eco-friendly, solvent-less and in situ approach. Structural elucidation was carried out using Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (¹H, ¹³C NMR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) techniques while morphological studies were performed using a scanning electron microscope (SEM/EDX), dynamic light scattering (DLS) and optical micrographs. Physico-chemical and physico-mechanical studies were tested to ASTM standards with a hydrophobic study measured by CA values. Further, the anticorrosive performance of the plain alkyd (alk-Pl) and alk-DDS-PPy-PSCeO₂-x nanocomposite-coatings were experimentally studied using potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS) and salt spray studies (SST). These studies revealed that nanocomposite (alk-DDS-PPy-PSCeO₂-1.5) coatings synthesized by the green and solvent-less approach exhibit higher physico-mechanical properties, hydrophobicity, adhesion and superior corrosion protective performance under acidic and saline environments in comparison to reported oleo-alkyds and other oleo-polymer nanocomposite coatings. The proposed oleo-alkyd nanocomposite-coatings are found to be ecologically reliable and thermally more stable and can be safely used up to 213 °C.