Experimental and theoretical studies on inhibition of mild steel corrosion by some synthesized polyurethane tri-block co-polymers

Abstract

Polyurethane based tri-block copolymers namely poly(N-vinylpyrrolidone)-b-polyurethane-b-poly(N-vinylpyrrolidone) (PNVP-PU) and poly(dimethylaminoethylmethacrylate)-b-polyurethane-b-poly(dimethylaminoethylmethacrylate) (PDMAEMA-PU) were synthesized through atom transfer radical polymerization (ATRP) mechanism. The synthesized polymers were characterized using nuclear magnetic resonance (NMR) spectroscopy and gel permeation chromatography (GPC) methods. The corrosion inhibition performances of the compounds were investigated on mild steel (MS) in 0.5 M H2SO4 medium using electrochemical measurements, surface analysis, quantum chemical calculations and molecular dynamic simulations (MDS). Potentiodynamic polarization (PDP) measurements revealed that the polymers are mixed-type corrosion inhibitors. Electrochemical impedance spectroscopy (EIS) measurements showed that the polymers inhibit MS corrosion by adsorbing on MS surface to form pseudo-capacitive interface. The inhibitive effects of the polymers increase with increasing concentration and decrease with increasing temperature. The adsorption of both the polymers on MS surface obey the Langmuir adsorption isotherm and involves both physisorption and chemisorption mechanisms. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) analyses showed that the polymers formed protective film on MS surface and shield it from direct acid attack. Quantum chemical calculations and molecular dynamic simulations studies corroborate experimental results.

Electrochemical and quantum chemical parameters of (-)-(S)-9-flu¬oro-2,3-dihydro-3-methyl-10-(4-methyl-1-pipera-zinyl)-7-oxo-7H-pyrido[1,2,3-de]-1,4-benzoxazine-6-carboxylic acidas anti-corrosive agent for API 5L X-52 steel

“…The resultant solution was filtered to obtain the stock solution of concentration 500 ppm. Solutions of concentrations 50, 100, 200 and 300 ppm were prepared from this stock solution using serial dilution method [17,18].…”

“…Figure 4 shows a complete geometric optimization of the studied molecule, while Figure 5 displays the frontier molecular orbitals namely, the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), present in studied compound. The calculated quantum chemical parameters obtained according to [16][17][18][19][20][21][22][23][24] are listed in Table 5.…”

Experimental and Theoretical Approach of Evaluating Chitosan Ferulic Acid Amide As An Effective Corrosion Inhibitor

“…The Nyquist plot clearly shows an increase in the diameter of the impedance plot with the inhibitor concentration. This increase can be attributed to the inhibitor film formation by protecting the metal surface from corrosion(Kumar et al 2016). The inhibition of corrosion is further supported by the rise in the phase angle with the increase in the inhibitor's concentration, as shown in the Bode plot(Yildiz 2015).…”

Recycling Polymeric Materials for Corrosion Control

“…Kumar et al [60] had reported polyurethane tri-block co-polymer as effective inhibitor of mild steel corrosion in acidic medium. The data indicated that the PU inhibits metal corrosion by adsorbing on metal surface to form pseudo-capacitive interface.…”