Anticorrosion Performance Of Epoxy Coatings Research Articles

Preparation and anticorrosion properties of BTA@HNTs-GO nanocomposite smart coatings

ABSTRACT Herein, a new strategy for improving anti-corrosion performance of epoxy coatings has been developed, which combined halloysite nanotubes (HNTs) with graphene oxide (GO). On one hand, the corrosion inhibitors loaded in nanocontainers will be released in the event of a coating damage that will subsequently prevent metal from further corrosion because of the pH-responsive ability of the nanocomposite. On the other hand, GO exerts the physical barrier property to protect metal matrix against corrosive medium. This endows the coating system with both active and passive protection performances. The release behavior of BTA loaded in the lumen of the HNTs was determined by UV–vis, and the dispersity of the composite in epoxy coating was evaluated by SEM. Electrochemical impedance spectroscopy (EIS) confirmed that the BTA@HNTs-GO hybrid composite has an excellent anti-corrosion performance.

Synergistic effect of polypyrrole functionalized graphene oxide and zinc phosphate for enhanced anticorrosion performance of epoxy coatings

A promising novel composite coating based on compound pigment of zinc phosphate and polypyrrole (PPy) functionalized graphene (ZGP) was reported for carbon steel in 3.5 wt% NaCl solution. Two ratios of PPy functionalized graphene oxide (GO-PPy) nanocomposites were prepared by in-situ polymerization of pyrrol (Py) on the surface of graphene oxide (GO). PPy film deposited on the surface of graphene oxide guaranteed excellent dispersion in the coating owing to hydrophilic groups. Embedding a small amount of ZGP-2 composite pigment (mPy/mGO = 2:1) into the waterborne epoxy coating significantly improved corrosion protection of the prepared composite coating. The corrosion protection mechanism of the desirable coating was attributed to the synergistic protection of impermeable GO-PPy nanosheets and passivation function of zinc phosphate, which was proved by the identification of corrosion products. Therefore, this work may provide a new direction for further study on compound pigments composed of functional graphene nanomaterials and inorganic salt inhibitors.

Liquid-like secondary amine containing POSS as reactive nanoadditive to improve the anticorrosion performance of epoxy coating

The octaaminopropyl polyhedral oligomeric silsesquioxane (OapPOSS) was firstly synthesized through hydrolytic condensation of 3-aminopropyltriethoxysilane. Then, the secondary amine containing POSS was prepared by Michael addition reaction of OapPOSS and diethyl maleate. The resulting hybrid nanomaterial is a viscous liquid that can be uniformly dispersed in the epoxy resin as a reactive component. Results of electrochemical impedance spectroscopy indicated that functionalized POSS significantly enhanced the anticorrosion performance of epoxy coatings. The POSS, acts as a cross-linkage, improved the crosslink density of resin matrix and enhanced the impermeability of composite coatings.

Anticorrosive epoxy coatings based on polydopamine modified molybdenum disulfide

Introducing inorganic layered nanomaterials into polymer arrays is one of the important methods to improve the anti-corrosion performance of epoxy coatings, but the compatibility between them is the first problem to be solved. In this study, lamellar molybdenum disulfide (MoS2) is modified by polydopamine (PDA) to improve its dispersibility and anti-corrosion properties in epoxy resin coatings. PDA is firstly coated onto the surface of MoS2 successfully, which can be proved by FT-IR, Raman and SEM. Then, the PDA modified MoS2 (MoS2 @ PDA) is introduced into epoxy resin system to prepare a new epoxy resin coatings (MoS2 @ PDA/EP). The anticorrosive performance of EP (pure epoxy coatings), MoS2/EP and MoS2 @ PDA /EP coatings are evaluated by electrochemical impedance spectroscopy spectra (EIS), polarization curve and pull-off adhesion tests. Compared to EP coating, the corrosion resistance of MoS2 @ PDA/EP coating has increased nearby three orders amount and the adhesion strength of MoS2 @ PDA/EP coating has increased nearby 3 Mpa. So, polydopamine modified MoS2 (MoS2 @ PDA) is an effective nanocomposite for preparing high-peroformane anticorrosion epoxy coatings.

Synergistic effect of homogeneously dispersed PANI-TiN nanocomposites towards long-term anticorrosive performance of epoxy coatings

Novel polyaniline-titanium nitride (PANI-TiN) nanocomposites were synthesized by one step chemical oxidation polymerization at a low temperature and PANI-TiN/epoxy coatings with enhanced corrosion resistance were obtained based on the synergistic effect of TiN nanoparticles and PANI nanorods. PANI-TiN nanocomposites and resultant epoxy coatings were characterized by Scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), Raman and X-ray photoelectron spectroscopy (XPS). Their anticorrosion performance in a 3.5 wt.% NaCl aqueous solution was investigated by the electrochemical impedance spectroscopy (EIS) and polarization curves. The results indicated that the corrosion resistance of PANI/epoxy coatings can be highly enhanced by introducing TiN nanoparticles to the PANI nanorods and the PANI-TiN/epoxy composite coating with 0.4 wt.% TiN (mass ratio to epoxy) exhibited the best corrosion protective performance, whose corrosion potential (Ecorr = −0.338 V) was positively shifted by 0.235 V compared with pure epoxy matrix (Ecorr = −0.573 V), and the corrosion current density was reduced by two orders of magnitude. The chemical structure of the rust layer and the anticorrosion mechanism were studied via X-ray diffraction analysis (XRD) and XPS. TiN nanoparticles showed a remarkably inhibiting effect on the agglomeration of PANI nanorods in epoxy coating. The corrosion resistance was attributed to the mixed mechanism of “passivation effect” of highly dispersed PANI and “labyrinth effect” of TiN nanoparticles.

ZrO2 nanoparticle encapsulation of graphene microsheets for enhancing anticorrosion performance of epoxy coatings

Graphene (rGO) is expected to enable an effective anti-corrosion barrier for metals owing to its chemical inertness and impermeability to gases and water. However, previous studies demonstrate limited anti-corrosion property and even corrosion enhancement of rGO on metal surfaces via micro-galvanic corrosion at the coating defects. To address the issue, in this work, sandwich-structured GZ microsheets is prepared by fully-covering the inert nanosized ZrO2 on the double-side of 2D rGO, and then incorporated into epoxy coating as filler for protecting metallic substrate against corrosion. By virtue of structural, morphological and electrochemical characterizations and analysis, we find that 0.5 wt% GZ into epoxy coating enables to form uniform and defect-free anticorrosive coating, and hence improve corrosion-protective properties in 3.5 wt% NaCl solution. The resistance of 0.5 wt% GZ in the first day immersion is 81.8 GΩ·cm2, and the metal substrate is not corroded during immersion. The attached inert ZrO2 shell on rGO effectively eliminates the rGO-metal/rGO connections, and hence prevents the local micro-galvanic corrosion.

Improving the anticorrosive performance of epoxy coatings

Improving the anticorrosive performance of epoxy coatings

Silver-embedded epoxy nanocomposites as organic coatings for steel

A novel hybrid nanomaterial based on silver nanoparticles, AgNPs, supported by 2,4-dihydrazino-6-(methoxypolyethyleneglycol)-1,3,5-triazine (mPEGTH) was prepared using solid phase technique. The synthesis process and the structural properties of the AgNPs were analyzed through X-ray diffraction (XRD), thermogravimetric analysis (TGA), transmittance and scanning electron microscopy (TEM and SEM). The effect of seawater, and pH of solutions on the aggregation and zeta potential of Ag NPs were characterized and identified. The Ag/mPEGTH, hybrid materials produced well dispersion and exhibit a remarkable superiority in enhancing the anticorrosion performance of epoxy coatings and fulfill a significant synergistic effect in anticorrosion and self-healing performance for epoxy composite coatings. The new self-healing mechanism of Ag/mPEGTH nanomaterial for the epoxy coating defects is tentatively proposed and discussed.

Improving the anticorrosive performance of epoxy coatings by embedding various percentages of unmodified and imidazole modified CeO2 nanoparticles

The surface of CeO2 nanoparticles was modified with imidazole as an effective corrosion inhibitive pigment via layer by layer method. At first, the surface of nanoparticles was coated by polyaniline via oxidative polymerization. Then, the imidazole layer was formed on polyaniline due to opposite electrostatic charges. The modification of nanoparticles by imidazole was investigated by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, thermogravimetric analysis (TGA), Dynamic light scattering (DLS) and Zeta potential (ZP) and Transmission electron microscopy (TEM). The anticorrosion performance of epoxy coating on mild steel in the presence of different concentrations of unmodified and imidazole modified CeO2 nanoparticles (0.5, 1 and 2 wt%) was evaluated in NaCl 3.5 wt% solution by electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). The optimum percentage of embedded CeO2 nanoparticles in the epoxy coating (unmodified and imidazole modified) was 0.5 wt% in which the coating has minimum agglomeration and appropriate corrosion resistance. The coating resistance of epoxy/imidazole modified CeO2 nanoparticles 0.5 wt% after 200 h immersion in NaCl 3.5 wt% solution was obtained 1.19 × 107 Ω cm2 which is higher than epoxy/unmodified CeO2 nanoparticles (6.51 × 106 Ω cm2). Also, the water uptake percentage of epoxy containing 0.5 wt% of imidazole modified CeO2 nanoparticles at the end of immersion time was obtained 3.85% which was lower than unmodified CeO2 nanoparticles (4.56%) due to inhibitive features and hydrophobicity of imidazole.

Dual functions of imidazole-based polymeric ionic liquid (PIL) on the anticorrosive performance of graphene-based waterborne epoxy coatings

Dispersion of graphene nanosheets in a water and polymer matrix has been rarely achieved due to graphene’s hydrophobicity, which thus impedes its potential anticorrosive application. In this study, stable graphene aqueous dispersion was obtained by using imidazole-based polymeric ionic liquid (PIL) as the dispersant with ultrasonic vibration. Stacked graphene sheets were exfoliated to a few layers via cation-π interaction between PIL and graphene nanosheets. Electrochemical impedance measurements were taken to investigate the anticorrosion performance of epoxy coatings with or without polymeric ionic liquid–graphene (PIL–G) hybrids. Results indicated that the PIL–G hybrid significantly enhanced the long-term protective performance of epoxy coatings, which was attributed to the synergistic effects of the corrosion-inhibitive PIL and impermeable graphene nanosheets.

Improvement of mechanical properties and anticorrosion performance of epoxy coatings by the introduction of polyaniline/graphene composite

We reported the preparation of epoxy coatings incorporated with a composite filler of poly(styrenesulfonate)-polyaniline/reduced graphene oxide (PSS-PANI/rGO) and their performance on the mechanical and anticorrosion properties. The rGO platelets were first dispersed in the PSS solution, followed by in situ oxidative polymerization of aniline. The resulting PSS-PANI/rGO composite was then blended with a bisphenol-A type epoxy at different loadings by tri-roller mill, and was subsequently cured with a curing agent. The ultimate tensile strength and tensile toughness of the epoxy composite at a loading of only 0.5 wt% PSS-PANI/rGO were improved by 39% and 127%, respectively, when compared to the respective values of the pristine epoxy. This was ascribed to their strong interfacial bonding upon curing by the reaction between the PANI and epoxy. Furthermore, the potentiodynamic polarization of the carbon steels coated with the epoxy/PSS-PANI/rGO composite revealed that the anticorrosion performance was greatly improved when compared to those with the neat epoxy and epoxy/rGO coatings. The superior anticorrosion effect was attributed to its larger tortuosity of diffusion pathways, improved interfacial strength between the epoxy and filler, and the passivation layer formed by the presence of polyaniline which was confirmed by X-ray photoelectron spectroscopy. The improved anticorrosion and toughness would allow the coatings to withstand externally mechanical impact and prevent corrosion effectively.

Evaluation of the anticorrosive performance of epoxy coatings containing new core/shell pigments

Purpose Core-shell is structured particles having several chemical compositions. The advantage of these particles arise from their specific design, to be used in decreasing costs by using inexpensive material (natural ore or waste material) as carrier for thin shell of active material. This study aims to prepare ferrites/silica core-shell pigments and compare their inhibition efficiency to original ferrites. These pigments have shells of different ferrites that comprise 10-15 per cent of the prepared pigments on silica fume. Silica fume which is the core is a byproduct in the ferro–silicon industry; this core comprises 85-90 per cent of the prepared pigments. Design/methodology/approach The prepared core-shell pigments were characterized using transmission electron microscopy analysis, energy-dispersive X-ray analysis and sequential wavelength dispersive X-ray fluorescence. These pigments were integrated in epoxy-based paint formulations, and the physical, mechanical and corrosion properties of dry films were examined. The corrosion properties were studied by using immersion test in 3.5 per cent NaCl for 28 days. Findings This study showed that these new eco-friendly and inexpensive pigments are similar to ferrites in their inhibition performance, i.e. they exhibited high corrosion prevention. Research limitations/implications Domestic waste materials were reused in paints and only simple modification was used, and then, their effectiveness showed similar performance to that of the original pigments. Originality/value Ferrite and ferrite/silica pigments are environmentally friendly pigments that can replace other hazardous pigments (e.g. chromates) with almost the same quality in their performance; also, they can be used in industries other than paints (e.g. paper, rubber and plastics composites).

Epoxy composites coating with Fe3O4 decorated graphene oxide: Modified bio-inspired surface chemistry, synergistic effect and improved anti-corrosion performance

To obtain graphene or graphene derivatives based epoxy composite coatings with high anti-corrosion performance, the morphology of nanostructures, dispersion, and interfacial adhesion are key factors that need to be considered. We here demonstrated the bio-inspired co-modification of graphene oxide/Fe3O4 hybrid (GO-Fe3O4@ poly (DA+KH550)) and its synergistic effect on the anti-corrosion performance of epoxy coating. For this purpose, graphene oxide/Fe3O4 hybrid obtained from hydrothermal route was modified by self-polymerization between dopamine and secondary functional monomer (KH550), which led to the modified bio-inspired surface functionalization. This novel modified bio-inspired functionalization was quite distinct from conventional surface modification or decoration. Namely, abundant amino groups were introduced by modified bio-inspired functionalization, which allowed the graphene oxide/Fe3O4 hybrid to disperse well in epoxy resin and enhanced the interfacial adhesion between modified nanofiller and epoxy resin through chemical crosslinking reaction. The electrochemical impedance spectroscopy (EIS) test revealed that anti-corrosive performance of epoxy coatings was significantly enhanced by addition of 0.5 wt% modified bio-inspired functionalized GO-Fe3O4 hybrid compared with neat epoxy and other nanofillers/epoxy composite coatings. Moreover, the micro-hardness of epoxy coating was enhanced by 71.8% compared with pure epoxy coating at the same loading content. In addition, the anticorrosion mechanism of GO-Fe3O4@poly (DA+KH550) was tentatively discussed.

Anti-corrosive performance of epoxy coatings containing various nano-particles for splash zone applications

Various formulations of epoxy nano-composites coating were developed by incorporating the nanoparticles (NPs) of ZnO, ZrO2, and SiO2 (2 wt%) in commercially available epoxy resin as the matrix phase. Direct incorporation method was used for the addition of NPs in epoxy matrix. High-speed mechanical stirring and ultra-sonication were carried out to facilitate the dispersion of NPs in the presence of acetone used as a solvent. Coating of neat epoxy and NPs (ZnO, ZrO2, SiO2) doped coating was applied on mild steel substrate for corrosion analysis. The effect of the incorporation of various NPs on anti-corrosive properties of the epoxy/nano-composite coatings was investigated by electrochemical impedance spectroscopy technique. The experimental results showed an improvement in the anticorrosive properties for EZr coatings as compared with pristine and other nanocomposite coating samples.

Effect of Montmorillonite Nanogel Composite Fillers on the Protection Performance of Epoxy Coatings on Steel Pipelines.

Montmorillonite (MMT) clay mineral is widely used as filler for several organic coatings. Its activity is increased by exfoliation via chemical modification to produce nanomaterials. In the present work, the modification of MMT to form nanogel composites is proposed to increase the dispersion of MMT into epoxy matrices used to fill cracks and holes produced by the curing exotherms of epoxy resins. The dispersion of MMT in epoxy improved both the mechanical and anti-corrosion performance of epoxy coatings in aggressive marine environments. In this respect, the MMT surfaces were chemically modified with different types of 2-acrylamido-2-methyl propane sulfonic acid (AMPS) nanogels using a surfactant-free dispersion polymerization technique. The effect of the chemical structure, nanogel content and the interaction with MMT surfaces on the surface morphology, surface charges and dispersion in the epoxy matrix were investigated for use as nano-filler for epoxy coatings. The modified MMT nanogel epoxy composites showed excellent resistance to mechanical damage and salt spray resistance up to 1000 h. The interaction of MMT nanogel composites with the epoxy matrix and good response of AMPS nanogel to sea water improve their ability to act as self-healing materials for epoxy coatings for steel.

Anticorrosion Performance of Epoxy Coating Containing Reactive Poly (o-phenylenediamine) Nanoparticles

The free amine-containing poly(o-phenylenediamine) (PoPD) nanoparticles with significant dispersibility in organic solvents have been synthesized by chemical oxidative polymerization of o-phenylenediamine mono-hydrochloride salt. The epoxy coatings with different contents of PoPD nanoparticles (0.5 wt%, 1 wt% and 2 wt%) were then prepared by curing reaction of epoxy resin, amine hardener and amine containing PoPD nanoparticles. The corrosion protection properties of the as prepared coatings on Q235 steel were investigated by potentiodynamic polarization, open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) technique in 3.5 wt % NaCl aqueous solution for 90 days. The results indicate that the coatings with 0.5 wt% PoPD nanoparticles (0.5-PDEP) exhibits high anticorrosive performance, which is attributed to the improved barrier effect of the nano-fillers and redox catalytic capability of embedded PoPD nanoparticles with the evidence of scanning electron microscope (SEM) and XRD. This novel amine-containing PoPD nanoparticles give a promising way to enhance the anticorrosion performance of epoxy coatings and potentially have a wider range of applications in anticorrosion related engineering applications.

Synergistic effect of functional carbon nanotubes and graphene oxide on the anti-corrosion performance of epoxy coating

In this work, we reported the synergistic effect of functional carbon nanotubes (CNTs) and graphene oxide (GO) on the anticorrosion performance of epoxy coating. For this purpose, the GO and CNTs were firstly modified by the 3-aminophenoxyphthalonitrile to realize the nitrile functionalized graphene oxides (GO-CN) and carbon nanotubes (CNTs-CN). As modified GO-CN and CNTs-CN were characterized and confirmed by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and gravimetric analyzer. It was found that about 19 and 24 wt% of 3-aminophenoxyphthalonitrile were grafted onto the surface of the GO and CNTs, respectively. The electrochemical impedance spectroscopy results showed that the GO-CN&CNTs-CN hybrid materials exhibit a remarkable superiority in enhancing the anticorrosion performance of epoxy coatings. Significant synergistic effect of the lamellar structural GO-CN and CNTs-CN on the anticorrosion performance of epoxy composite coatings was designed. Besides, the epoxy coating with 1 wt% of the GO-CN&CNTs-CN hybrid exhibited the best anticorrosion performance, in which the impedance showed the largest one (immersion in 3.5 wt% of NaCl solution for 168 hr). Copyright © 2016 John Wiley & Sons, Ltd.

Effect of polyaniline-modified glass fibers on the anticorrosion performance of epoxy coatings

Polyaniline (PANI) and different mass ratios of polyaniline/glass fiber (GB) composites (PANI/GB, PGB) were prepared through in situ oxidative polymerization. The chemical structure of composites was investigated via Fourier transform infrared spectroscopy and X-ray diffraction. Epoxy coatings loaded with different mixtures of PANI and GB were applied on steel substrate and exposed to NaCl solution. The morphological properties and corrosion resistance of the coatings were investigated through environmental scanning electron microscopy, electrochemical impedance spectroscopy, and salt spray tests. Results showed that the addition of PANI, GB, and PGB composites caused an improvement in corrosion resistance. The greatest improvement in corrosion resistance was exhibited by the coatings loaded with mass ratio of 1:1 of PANI/GB. This enhancement was attributed to the corrosion resistance of PANI and penetration resistance of GB. Moreover, the uniform distribution of PGB composites in the epoxy resin is an important parameter affecting corrosion resistance of the coatings.

Poly(dopamine) assisted epoxy functionalization of hexagonal boron nitride for enhancement of epoxy resin anticorrosion performance

Hexagonal boron nitride (h-BN) is modified by a simple and green method based on self-oxidation of dopamine and epoxy groups functionalized silane (KH560) grafting. The surface modification and microstructure of h-BN are characterized by Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy. The poly(dopamine) and epoxy groups not only increase the compatibility of the h-BN and enhance its interaction with epoxy matrix but also exhibit a remarkable superiority in enhancing the anticorrosion performance of epoxy coatings. In addition, the anticorrosion mechanisms of h-BN@PDA-KH560 are tentatively discussed. Copyright © 2016 John Wiley & Sons, Ltd.

H-BN decorated with Fe3O4 nanoparticles through mussel-inspired chemistry of dopamine for reinforcing anticorrosion performance of epoxy coatings

A novel hybrid materials Fe3O4 nanoparticles supported by hexagonal boron nitride (h-BN) is successfully prepared via mussel-inspired chemistry of dopamine by hydrothermal synthesis method. The surface modification and microstructure of h-BN-Fe3O4 are characterized by FT-IR, XRD, XPS, SEM and TEM. The nano-Fe3O4 obtain well dispersion supported by h-BN layer platform, and the h-BN-Fe3O4 hybrid materials exhibit a remarkable superiority in enhancing the anticorrosion performance of epoxy coatings. The lamellar structural h-BN and nano-Fe3O4 provide a significant synergistic effect in anticorrosion performance for epoxy composite coatings. In addition, the anticorrosion mechanisms of h-BN-Fe3O4 are tentatively discussed.