Potential Impacts of Prunus domestica Based Natural Gum on Physicochemical Properties of Polyaniline for Corrosion Inhibition of Mild and Stainless Steel

Abstract

The lack of an eco-friendly approach towards application of polyaniline as a coating material has been one of the most challenging tasks. Herein, the synthesis of green Prunus domestica gum grafted polyaniline (PDG-g-PANI) composite is reported by a cost-effective emulsion polymerization for application as an efficient anti-corrosion material for mild steel (MS) and stainless steel (SS) in a strong corroding environment. The composite formation was confirmed by Ultraviolet Visible (UV-Visible) and Fourier Transformed Infrared (FTIR) spectroscopies. X-ray diffraction data revealed the amorphous nature of the PDG-g-PANI. Scanning Electron Microscopic (SEM) images showed a bi-layered structure having a parent porous layer of PANI coated with afibrous layer of PDG. The solubility test confirmed the dissolution of PDG-g-PANI in common organic solvents such as acetone, ethanol, propanol, butanol, chloroform, N-Methyl-2-pyrrolidone, dimethyl sulfoxide, and the mixture of propanol and chloroform. The polarization curve, open circuit potential, electrochemical impendence spectroscopy (EIS), and gravimetric analysis were applied to investigate the corrosion protection behavior of the composite on MS and SS in 3.5% NaCl and 1 M H2SO4 solution. The PDG-g-PANI-coated MS exhibited 96% corrosion inhibition efficiency as compared to 86% and 43% for pristine PANI and PDG in 3.5% NaCl solution while PDG-g-PANI-coated SS showed 98% corrosion inhibition efficiency. Moreover, 99% and 96.6% corrosion protection was observed for PDG-g-PANI-coated MS and SS in 1 M H2SO4 solution. Gravimetric studies revealed that PDG-g-PANI coating can protect MS up to 93% for 14 days in salt solution while 97% corrosion inhibition efficiency was retained for 2 months in open air.

Investigation of Alumina-Doped Prunus domestica Gum Grafted Polyaniline Epoxy Resin for Corrosion Protection Coatings for Mild Steel and Stainless Steel

“…It was found that the composite is soluble in alcohols, especially methanol and ethanol/propanol, which is due to the presence of polar components such as –NH and –OH, which are responsible for the solubility in polar solvents. Such solubility can be attributed to the formation of hydrogen bonds between composites and alcohols [ 20 ]. The same phenomenon occurred when the composite approached NMP and THF, albeit these solvents differ significantly from alcohols.…”

“…The region at 556 nm is attributed to the π-polaron transition, while the peak at 407 nm is attributed to the polaron π*-transition of the quinoid ring. Peaks at 301 nm and 261 nm are attributed to the π-π*-transition of the benzoid ring and the arabinogalactose component of PDG, respectively [ 20 ]. The UV/Vis spectra of PDG-g-PANI/Al 2 O 3 gave three sharp peaks at 251 nm, 290 nm, and 403 nm, while there was one broad peak at 573 nm.…”

“…Figure 3 shows the FTIR spectra of PDG, PANI, PDG-g-PANI, and PDG-g-PANI/Al 2 O 3 , and the peak assignments concerned are given in Table 1 [ 20 ]. In the spectrum of PDG-g-PANI/Al 2 O 3 , the bands at 2917 cm −1 and 2847 cm −1 are due to coupled stretching vibrations of the aliphatic C-H of PDG and C-H of aniline in the polymer chain.…”

“…PANI exhibits a porous morphology while the PDG shows irregular surface characteristics. The image of PDG-g-PANI displays a porous surface of PANI having a PDG network surrounding the porous network of PANI [ 20 ]. For PDG-g-PANI/Al 2 O 3 it can be seen that all three components including PANI, PDG, and Al 2 O 3 particles are present in the composite.…”

“…However, the environmental benefits of PANI, such as the introduction of materials from plants with excellent insulating and mechanical properties, have been little explored. These green materials are natural gums used alone or in combination with conductive polymers and metal oxides as coating materials for the corrosion protection of metals [ 20 ]. Natural gums are usually carbohydrates with electron-rich hydroxy functional groups that assist adhesion by forming a covalent bond with metal surfaces, thus forming an insulating layer, and reducing corrosion [ 21 , 22 ].…”