Development And Performance Evaluation Of Smart Polymeric Coatings For Corrosion Protection Of Steel

Abstract

Most common cause of materials and equipment failure in the oil and gas industry is corrosion. According to one survey, about 1/4 to 1/3 of the total downtime in plants is due to deleterious effects of corrosion. It is, therefore, essential to prevent corrosion to ensure reliability of the assets. Usually, Protection of piping steel against corrosion is achieved by applying thick barrier coatings. These coatings provide decent barrier protection against ageing, mechanical scratches, erosion and other damages. Protection of damaged piping parts requires steel repair and re-coat which is an expensive process. To minimize the impact of damages and subsequent corrosion activity of the steel is essential to act promptly and efficiently, preferably in an autonomous way. Modern trends indicate that smart functional coatings, containing autonomous self-healing species are attractive for prolonged lifetime of materials. These coatings can heal damages at early stage, minimizing corrosion onset and corrosion propagation. Consequently, they are a promising solution for longer durability of coated piping steel and decreased operation expense. If properly designed, smart self-healing coatings also help to reduce the overall thickness of the coating scheme as well as the investment cost. Altogether, this strategy contributes to economic saves, materials reliability and safety. The current research work summarizes the synthesis and characterization of polymeric smart coatings developed by reinforcing urea formaldehyde microcapsules encapsulated with linalyl acetate and polyelectrolyte multilayered microcapsules (with two different corrosion inhibitors in the polyelectrolyte layers) into epoxy matrix. In situ polymerization technique was used for the synthesis of urea formaldehyde microcapsules encapsulated with linalyl acetate, whereas layer by layer technique was adopted to develop multilayered microcapsules containing alternative layers of Polyethyleneimine (PEI) and sulphonated polyether ether keytone (SPEEK). Dodecylamine (DOC) and phenylethiourea (PTU) were loaded as corrosion inhibitors in between polyelectrolyte layers of PEI and SPEEK. The prepared microcapsules (each 6.0 wt.% ) were uniformly dispersed into the epoxy resin to develop single layer coatings (reinforced with urea formaldehyde microcapsules) and multilayered smart coatings (reinforced with multilayered microcapsules). The anticorrosive performance of the fabricated coatings was evaluated in 3.5 % NaCl solution at room temperature. Experimental results confirm that smart coatings with multilayered microcapsules demonstrate improved self-healing and anti-corrosion properties when compared to other type of coatings. This improvement can be attributed to efficient release of self healing and corrosion inhibiting species (DOC and PTU) from the multilayered microcapsules. The tempting properties of multilayered coatings make them attractive for oil and gas industries.