Zinc Oxide Nanocomposites of Selected Polymers: Synthesis, Characterization, and Corrosion Inhibition Studies on Mild Steel in HCl Solution

Abstract

Nanocomposites of ZnO and some selected polymers, namely, poly(ethylene glycol), poly(vinylpyrrolidone), and polyacrylonitrile, were synthesized and characterized using Fourier transform infrared (FTIR) spectroscopy, ultraviolet–visible (UV–vis) spectroscopy, thermogravimetric analysis (TGA), and transmission electron microscopy (TEM) techniques. The FTIR and UV–vis spectra confirmed the successful formation of the polymer nanocomposites. TGA results revealed that the synthesized polymer nanocomposites are more thermally stable than the polymers alone. ZnO nanoparticles were about 50–75 nm in size, assumed a rodlike shape, and got embedded in the polymer matrices, as revealed by TEM images. Corrosion inhibition potentials of the synthesized ZnO/polymer nanocomposites were investigated for mild steel in 5% HCl solution using potentiodynamic polarization (PDP), linear polarization resistance, and electrochemical impedance spectroscopy measurements. The results showed that each ZnO/polymer nanocomposite inhibits mild steel corrosion in 5% HCl solution better than the respective polymer alone. The nanocomposites, according to PDP studies, behaved as a mixed-type inhibitor. The predominant mode of adsorption of the nanocomposites to a mild steel surface was found to be mixed type, and the adsorption process obeys the Langmuir adsorption isotherm model. Scanning electron microscopy images also revealed the protective attributes of the ZnO/polymer nanocomposites for mild steel in 5% HCl solution.

In-vitro evaluation of antibacterial and antibiofilm efficiency of radiation-modified polyurethane–ZnO nanocomposite to be used as a self-disinfecting catheter

“…The disappearance of the epoxy ring characteristic peaks and the appearance of broadness due to (-OH) group generation, upon refluxing, confirmed the covalent immobilization of cefepime and the formation of PU-g-(AAc-co-GMA)-cefepime. Additionally, the appearance of the characteristic Zn −O stretching vibration bands (Quadri, Olasunkanmi, Fayemi, Solomon, & Ebenso, 2017)confirmed the development of the nanocomposite. The (-COOH) of acrylic acid helps entrap ZnO as evidenced by the broadness of the peak noticed in the range of 3200-3600 cm −1 corresponding to the stretching vibration of the (O-H) bond due to the formation of intermolecular hydrogen bonds, in addition to the bending vibration peak that appeared at 1627 cm −1 (Sakthivel, Mallika, Kannusamy, & Rajendran, 2016).…”

Synthesis of ZnO-NPs Using a Convolvulus arvensis Leaf Extract and Proving Its Efficiency as an Inhibitor of Carbon Steel Corrosion

“…The high temperature increased i corr [28], but the effect of the inhibitor remained the same at a temperature of 298 K. Its effect at 333 K almost became constant above ZnO-NPs concentrations of 0.06 mg/mL, showing that even at high temperatures [27], when the surface of the electrode is saturated with inhibitor molecules [29], the inhibition mechanism remains functional. The presence of ZnO-NPs, in addition to the molecules of the Convolvulus arvensis leaf extract on the carbon steel surface, form a protective layer that limits anodic and cathodic reactions and thus reduces the rate of corrosion [18]. Figure 5 illustrates the results of an electrochemical impedance technique to determine the corrosion behavior of carbon steel in 1 M HCl in the absence and presence of ZnO-NPs at temperatures of 298 and 333 K using electrochemical impedance spectroscopy (EIS).…”

“…The Bode and phase angle diagrams showed increased area under the curves in the presence of the inhibitor compared to a blank solution. The corrosion resistance may be significantly increased with an increase in inhibitor concentrations [18]. The increase in R ct and the decrease in C dl with the increase in inhibitor concentration is due to the decrease in dielectric constant and/or increase in the thickness of the electrical double layer, which indicates that the ZnO-NPs act through an adsorption mechanism at the interface of the carbon steel/HCl solution [17].…”

Acridine-based thiosemicarbazones as novel inhibitors of mild steel corrosion in 1 M HCl: synthesis, electrochemical, DFT and Monte Carlo simulation studies

“…Similar observations has been reported previously. 50,51 The standard free energies of adsorption DG o ads were calculated from eqn (7) using values of K ads obtained from Langmuir isotherm, with R and T having their usual meanings and 55.5 represent the molar concentration of water in solution: 52 DG o ads ¼ ÀRT ln(55.5 K ads )…”