Anticorrosive Performance Approach Combining an Epoxy Polyaminoamide–Zinc Phosphate Coatings Applied on Sulfo-tartaric Anodized Aluminum Alloy 5086

Properties and Performance of Epoxy Resin/Boron Acid Composites

This research study focused on the effect of adding boric acid to epoxy resin in order to obtain a composite material with improved properties and performance. To this end, a fine powder of boric acid (H3BO3) was introduced into epoxy resin in different amounts, i.e., 0.5 g, 1.0 g, and 1.5 g. As the matrix of the epoxy composites, styrene-modified epoxy resin based on bisphenol A (BPA) (Epidian 53) was used. It was cross-linked with two types of curing agents, i.e., an amine (ET) and a polyamide (PAC). The mechanical properties of the obtained epoxy composites (in terms of compressive strength, compressive modulus, and compressive strain) were determined at room temperature in order to assess the effect of the addition of boron acid and of the type of curing agent employed to cure the epoxy on these characteristics. Calorimetric measurements were made to highlight any changes in the glass transition temperature (Tg) as a result of the addition of boric acid to epoxy resin. Finally, flammability tests were performed on both Epidian 53/PAC and Epidian 53/ET epoxy composites to analyze their fire behavior and consequently establish the effectiveness of the selected additive as a flame retardant.

Mechanical Properties of Epoxy Compounds Based on Unmodified Epoxy Resin Modified with Boric Acid as an Antiseptic

The objective of this study was to compare the selected mechanical properties of epoxy compounds based on an unmodified epoxy resin with those containing an antiseptic as a modifying agent. Experiments were carried out on twelve epoxy compounds made of an epoxy resin based on bisphenol A (BPA) with a basic epoxide amount of 0.48-0.51 mol/100 g. Three curing agents were used: one polyamide (a polyaminoamide curing agent) and two amines (one was an adduct of aliphatic amine and aromatic glycidyl ether, and the other was an adduct of cycloaliphatic amine). The epoxy compounds were modified by adding an antiseptic in the form of powdered boric acid (H3BO3) in three amounts: 0.5 g, 1.0 g, and 1.5 g. The cured modified and unmodified epoxy compounds were subjected to compressive strength testing and microscopic examination. The experimental results showed that the epoxy compounds containing adduct of aliphatic amine (triethylenetetramine) and aromatic glycidyl ether as the amine curing agent, i.e., E5/ET/100:18, had the highest compressive strength out of all the tested epoxy compounds, with the highest value of 119 MPa obtained for the epoxy compound modified by the addition of 1.0 g boric acid. The epoxy compounds modified with boric acid acquired antiseptic properties and, for most cases, exhibited a higher compressive strength than the unmodified epoxy compounds (not lower than that specified by the manufacturer for unmodified epoxy compounds).

8-Hydroxyquinoline based chitosan derived carbohydrate polymer as biodegradable and sustainable acid corrosion inhibitor for mild steel: Experimental and computational analyses

The present study reports the synthesis, characterization and corrosion inhibition effects of chitosan (CH) and its 5-chloromethyl-8-hydroxyquinoline derivative (CH-HQ) for mild steel in acidic medium. The synthesized CH-HQ was characterized using ¹H NMR and FT-IR spectroscopic methods. Corrosion inhibition efficiencies of CH and CH-HQ were measured using electrochemical and chemical techniques. The surface protection ability of the inhibitor molecules was also ascertained by surface analysis, while computational study was used to further justify the adsorption tendencies of the molecules on mild steel surface. CH-HQwasobserved to exhibit better protection efficiency than CH, as the highest inhibition efficiencies were recorded to be 78% and 93% for CH and CH-HQ, respectively. Potentiodynamic polarization studies revealed that CH and CH-HQ are mixed-type corrosion inhibitors over the studied temperature range (298 K ± 1 to 328 K ± 1). SEM-EDS studies were performed to demonstrate the adsorption of CH and CH-HQ on the mild steel surface. Adsorption behavior of the CH and CH-HQ was also supported by UV-visible (UV-vis) spectrophotometric analyses. Monte Carlo simulations (MC) and density functional theory (DFT) calculations were carried out to corroborate the experimental results.

Epoxy pre-polymers as new and effective materials for corrosion inhibition of carbon steel in acidic medium: Computational and experimental studies

Present study is designed for the synthesis, characterization and corrosion inhibition behavior of two diamine aromatic epoxy pre-polymers (DAEPs) namely, N1,N1,N2,N2-tetrakis (oxiran-2-ylmethyl) benzene-1,2-diamine (DAEP1) and 4-methyl-N1,N1,N2,N2-tetrakis (oxiran-2-ylmethyl) benzene-1,2-diamine (DAEP2) for carbon steel corrosion in acidic medium. Synthesized DAEPs were characterized using spectral (Nuclear magnetic resonance (1H NMR) and Fourier transform infrared-attenuated total reflection (FTIR-ATR)) techniques. Viscosity studies carried out at four different temperatures (20-80 °C) increase in temperature causes significant reduction in their viscosities. The anticorrosive properties of DAEPs differing in the nature of substituents, for carbon steel corrosion in 1 M HCl solution was evaluated using several experimental and computational techniques. Both experimental and computational studies showed that inhibitor (DAEP2) that contains electron releasing methyl (-CH3) showed higher protectiveness as compared to the inhibitor (DAEP1) without substituent (-H). Electrochemical results demonstrate that DAEPs act as reasonably good inhibitors for carbon steel in 1 M HCl medium and their effectiveness followed the sequence: DAEP2 (92.9%) > DAEP1 (91.7%). The PDP results show that the diamine aromatic epoxy pre-polymers molecules (DAEPs) act as mixed type inhibitors. Electrochemical study was also supported using scanning electron microscopy (SEM) method were significant improvement in the surface morphology of inhibited (by DAEPs) metallic specimens was obtained. Results derived from computational density functional theory (DFT) and molecular dynamics (MD) simulationsand studies were consistent with the experimental results derived from SEM, EIS and PDP electrochemical studies. Adsorption of the DAEPs obeyed the Langmuir adsorption isotherm model.

Dual Component Polymeric Epoxy-Polyaminoamide Based Zinc Phosphate Anticorrosive Formulation for 15CDV6 Steel

The present research is focused on a formulation with two active components as an anticorrosive polymer coating for 15CDV6 steel. The dual component formulation (epoxy-zinc phosphate (ZP) coating) consists of a polymeric epoxy resin Bisphenol A diglycidyl ether (DGEBA) cured with a polyaminoamide as a first component and zinc phosphate (Zn3(PO4)2(H2O)4) (ZP) added in 5% by weight as a second component. The anticorrosive performance of the epoxy-ZP coating was evaluated against the standard coating, which consists of only one component, the cured polymeric epoxy resin. The two polymer coatings were evaluated by electrochemical impedance spectroscopy (EIS). The surface morphology was of the two polymer coatings were characterized by scanning electron microscopy (SEM). The coated samples of 15CDV6 steel were tested in a harsh environment of corrosive electrolytes (3 wt % NaCl solution). Under these conditions, a very high impedance value was obtained for 15CDV6 steel coated with the epoxy-ZP coating. Even after exposure for a long period of time (5856 h), the performance was still acceptable, indicating that the epoxy-ZP coating is an excellent barrier. The standard epoxy coating provided an adequate corrosion protection performance for a short period of time, then the performance started to decline. The results were confirmed by surface characterization, a cross-sectional image obtained by optical microscopy for an epoxy-ZP coating applied on 15CDV6 steel exposed for 5856 h to a salt spray test showed that the coating is homogeneous and adheres well to the surface of the steel. So, the coating with a dual component could have great potential in marine applications as anticorrosive for steel.

Anticorrosive properties of Hexa (3-methoxy propan-1,2-diol) cyclotri-phosphazene compound for carbon steel in 3% NaCl medium: gravimetric, electrochemical, DFT and Monte Carlo simulation studies

The corrosion inhibition performance of Hexa (3-methoxy propan-1,2 diol) cyclotriphosphazene (HMC) on carbon steel in 3% NaCl solution was investigated by weight loss (WL), potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS) measurements, Density functional theory (DFT) and Monte Carlo (MC) simulation. The corrosion inhibition efficiency at optimum concentration (10-3M) is 99% of HMC at 298 K. The corrosion inhibition efficiency at 10-3 M decreases with increase in temperature. The adsorption of HMC on the surface of carbon steel obeyed Langmuir isotherm. Potentiodynamic polarization study confirmed that inhibitor anodic-type. DFT and Monte Carlo (MC) simulations based computational approaches were under taken to support the experimental findings. DFT studies revealed that HMC interact with metallic surface through donor-acceptor interactions in which the anionic parts act as electron donor (HOMO) and cationic parts behaved as electron acceptor (LUMO). The MC simulations study showed that studied HMC adsorb spontaneously on Fe (110) surface.

Rheological, electrochemical, surface, DFT and molecular dynamics simulation studies on the anticorrosive properties of new epoxy monomer compound for steel in 1 M HCl solution

A new epoxy monomer, namely, tetraglycidyl-1,2-aminobenzamide (ER), was synthesized by condensation of the amines with epichlorohydrin in a basic medium. The obtained epoxy monomer was characterized by FT-IR and ¹H NMR spectroscopy. Rheological properties of this monomer were determined using an advanced rheometer. Subsequently, the synthesized ER monomer was investigated as corrosion inhibitor for carbon steel in 1 M HCl solution. The adsorption properties of ER were analyzed by electrochemical, surface investigation and theoretical computational studies using DFT and molecular dynamics (MD). Results showed a high dependence of the viscosity of ER on temperature and concentration, and also, that ER has better inhibition performance. A good agreement between the results derived from computational (MD and DFT) and experimental methods was observed. The thermodynamic parameters, along with the kinetic parameters, showed that the adsorption of ER molecules onto carbon steel surface obeyed the Langmuir isotherm model, and the adsorption at metal–electrolyte interfaces involved both chemical and physical adsorption, but predominantly chemisorption mechanism.

A new epoxy monomer, namely, tetraglycidyl-1,2-aminobenzamide (ER), was synthesized by condensation of the amines with epichlorohydrin in a basic medium.

Adsorption and anticorrosive behavior of aromatic epoxy monomers on carbon steel corrosion in acidic solution: computational studies and sustained experimental studies

Herein, the synthesis, characterization and corrosion inhibition effectiveness of two aromatic epoxy monomers (AEMs) namely, 2-(oxiran-2-yl-methoxy)-N,N-bis(oxiran-2-yl-methyl)aniline (AEM1) and N,N-bis(oxiran-2-ylmethyl)-2-((oxiran-2-ylmethyl) thio)aniline (AEM2), in carbon steel corrosive dissolution in 1 M HCl solution is investigated using computational and experimental techniques. AEM1 and AEM2 were characterized using FT-IR, ¹H NMR and ¹³C NMR spectroscopy techniques. Electrochemical results demonstrated that AEMs act as reasonably good corrosion inhibitors for carbon steel in 1 M HCl medium and their effectiveness followed the sequence: AEM2 (95.4%) > AEM1 (94.3%). A PDP study showed that AEMs act as mixed-type inhibitors with slight anodic predominance. Adsorption of the AEMs obeyed the Langmuir isotherm model. Interactions between AEMs and the metallic surface was further studied using DFT and MD simulations that give several computational parameters such as I, A, E_HOMO, E_LUMO, ΔE, δ, χ, ρ, σ, η, ΔN and E_ads. The experimental and computational results were in good agreement and well complimented each other.

Herein, the synthesis, characterization and corrosion inhibition effectiveness of two aromatic epoxy monomers (AEMs) in carbon steel corrosive dissolution in 1 M HCl solution was investigated using computational and experimental techniques.