Corrosion and corrosion control

Conducting polymers (CPs) such as polyaniline (PANI), polypyrrole (PPy), and polythiophene (PTh) are used for the corrosion protection of metals and metal alloys. Several groups have reported diverse views about the corrosion protection by CPs and hence various mechanisms have been suggested to explain anticorrosion properties of CPs. These include anodic protection, controlled inhibitor release as well as barrier protection mechanisms. Different approaches have been developed for the use of CPs in protective coatings (dopants, composites, blends). A judicious choice of synthesis parameters leads to an improvement in the anticorrosion properties of the coatings prepared by CPs for metals and their alloys. This article is prepared as a review of the application of CPs for corrosion protection of metal alloys.

Conducting polymers for corrosion protection: a review

Protective polymeric films for industrial substrates: A critical review on past and recent applications with conducting polymers and polymer composites/nanocomposites

The direct electrodeposition of electroactive conducting polymers on active metals such as iron and aluminum is complicated by the concomitant metal oxidation that occurs at the positive potentials required for polymer formation. In the case of aluminum and its alloys, the oxide layer that forms is an insulator that blocks electron transfer and impedes polymer formation and deposition. As a result, only patchy nonuniform polymer films are obtained. Electron transfer mediation is a well-known technique for overcoming kinetic limitations of electron transfer at metal electrodes. In this work, we report the use of electron transfer mediation for the direct electrodeposition of polypyrrole onto aluminum and onto Al 2024-T3 alloy. This report focuses on the use of Tiron (4,5-dihydroxy-1,3-benzenedisulfonic acid disodium salt) as the mediator, although catechol appears to function in a similar manner. Depositions were carried out under galvanostatic conditions at current densities of The mediator reduced the deposition potential by nearly 500 mV compared to deposition performed in the absence of mediator (where Tiron was replaced by p-toluene sulfonic acid sodium salt). Polypyrrole formation and deposition appears to occur with 100% current efficiency and uniform films are obtained. Results of the characterization of these films by scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, conductivity measurements, and adhesion measurements are presented. © 2002 The Electrochemical Society. All rights reserved.

Direct Electrodeposition of Polypyrrole on Aluminum and Aluminum Alloy by Electron Transfer Mediation

Blends and composites of exopolysaccharides; properties and applications: A review

Electrochemical and chemical oxidation methods are the two common methods used for the preparation of poly(pyrrole). The two methods have been acknowledged greatly and extensively studied because of their feasibility in manipulating the properties of poly(pyrrole) according to the desired application. However, chemical oxidation method is considered the best method for the preparation of poly(pyrrole) in larger quantities. There are other methods through which poly(pyrrole) can be synthesized such as plasma polymerization and photopolymerization, which have so far received less attention in the literature. For this paper, chemical oxidation was used to prepare poly(pyrrole) by oxidizing pyrrole with CuCl2 under different emulsifying conditions. The surfactants used were sodium dodecyl sulfate and/or p-toluenesulfonic acid. Additionally, photopolymerization was also exploited to prepare poly(pyrrole) under similar emulsifying conditions. In this method, poly(pyrrole) was synthesized with the oxidizing ability of AgNO3 under UV radiation. All samples were investigated by Fourier Transform-Infrared Spectroscopy (FT-IR), X-ray Photoelectron Spectroscopy (XPS), and Powder X-ray Diffraction (XRD). Scanning electron microscope was used to compare the morphological differences, which occurred due to different experimental conditions. The thermal stability was studied using thermogravimetric analysis (TGA).

A structural and morphological comparative study between chemically synthesized and photopolymerized poly(pyrrole)

Corrosion and corrosion-induced damage have resulted mostly in malfunctions and sometimes even in failures of metallic structures, including oil and gas pipelines. In this study, new high-performance composite coatings were developed by incorporating nanoparticles in the polymer resins with applications to oil and gas pipelines. The graphene nanoplatelets under different concentrations were used to prepare the epoxy-based nanocomposites and were then evaluated through mechanical and electrical tests. The integration of high-speed disk and ultrasonication were adopted as the dispersion technique to overcome nanoparticle agglomeration. Electron microscopy techniques were used to investigate the agglomeration. The new composites were qualitatively and quantitatively evaluated in terms of contact angle, surface roughness, adhesion to the substrate, corrosion resistance, and abrasion resistance. The results suggested that the composite with 0.5~1.0 wt.% of the graphene nanofillers led to the largest improvement in both mechanical and electrochemical properties. Distribution of nanoparticles in the matrix was observed using scanning electron microscopy and surface roughness using atomic force microscopy. Large agglomeration that was observed at the higher concentrations mainly resulted in the reduction of corrosion resistance and abrasion resistance.

https://www.mdpi.com/2079-4991/8/12/1005/pdf

Graphene Reinforced Composites as Protective Coatings for Oil and Gas Pipelines.

Even though commercially coating systems, such as epoxy resin, have been used as structural coatings, the challenges are the defeats or voids experienced in these coatings during curing stages that hinder their long-term barriers performance. Also, low damage tolerance often leads to premature coating degradation. In this study, the new high-performance composite coatings were developed by incorporating graphene nanoplatelets in the epoxy resin. a comprehensive characterization of the new graphene-loaded composite coatings, including electrochemical behavior, tensile strength, ultimate strain, abrasion properties, and long-term durability performance, was investigated. The results demonstrated that the graphene-loaded composite coatings exhibited a significant improvement in resistance to abrasion and corrosion inhibition property. Improvement of mechanical properties of the graphene-loaded coatings in terms of tensile strength, failure strain and abrasion resistance allowed high damage tolerance for more broader engineering applications. Moreover, long-term durability tests further confirmed the coating loaded with a small amount of a graphene nano-reinforcement, such as 1.0% of graphene by weight, could display the high corrosion resistance by 75% of remaining capacity after 500-h exposure, as compared to the neat epoxy with a low value of 40% or less.

Mechanical, electrochemical, and durability behavior of graphene nano-platelet loaded epoxy-resin composite coatings

One-coat epoxy coating development for the improvement of UV stability by DPP pigments

Corrosion accounts for huge maintenance cost in the pipeline community. Promotion of protective coatings used for oil/gas pipeline corrosion control, in terms of high corrosion resistance as well as high damage tolerance, are still in high demand. This study was to explore the inclusion of nanoparticle fullerene-C60 in protective coatings for oil/gas pipeline corrosion control and mitigation. Fullerene-C60/epoxy nanocomposite coatings were fabricated using a solvent-free dispersion method through high-speed disk (HSD) and ultrasonication. The morphology of fullerene-C60 particles was characterized by transmission electron microscopy (TEM), and dynamic light scattering (DLS). The data analysis indicated that the nanoparticles were effectively dispersed in the matrix. The performance of the nanocomposites was investigated through their mechanical and electrochemical properties, including corrosion potential, tensile strength, strain at failure, adhesion to substrate, and durability performance. Dogbone shaped samples were fabricated to study the tensile properties of the nanocomposites, and improvement of strength, ultimate strain, and Young's modulus were observed in the C60/epoxy specimens. The results demonstrated that the C60/epoxy composite coatings also had improvements in adhesion strength, suggesting that they could provide high damage tolerance of coatings for engineering applications. Moreover, the electrochemical impedance spectroscopy (EIS) results generated from the accelerated durability test revealed that the developed fullerene-C60 loaded composite coatings exhibited significantly improved corrosion resistance. The nanocomposite with 0.5 and 1.0 wt.% of C60 particles behaved as an intact layer for corrosion protection, even after 200-h salt spray exposure, as compared to the control coating without nanofiller in which severe damage by over 50% reduction was observed.

Xiaoning Qi

Papers

A structural and morphological comparative study between chemically synthesized and photopolymerized poly(pyrrole)

Graphene Reinforced Composites as Protective Coatings for Oil and Gas Pipelines.

Mechanical, electrochemical, and durability behavior of graphene nano-platelet loaded epoxy-resin composite coatings

One-coat epoxy coating development for the improvement of UV stability by DPP pigments

Enhanced Protective Coatings Based on Nanoparticle fullerene C60 for Oil & Gas Pipeline Corrosion Mitigation.