DESIGNING A DYNAMIC CORROSION RESISTANCE SYSTEM USING GREEN INHIBITORS MODIFIED GRAPHENE OXIDE MICROCAPSULES FOR IMPROVING THE ADHESION STRENGTH OF THE EPOXY COATINGS

Abstract

Corrosion causes severe damages to industrial and economical objects and creates a risk to mankind. This gradual deterioration of metallic supplies either by chemical or electrochemical means could not be completely prevented. However, various techniques were developed for minimizing this destruction process and improve the adhesion properties. The application of protective coatings gathers global interest due to its practical construction and ability to provide better protection against corrosion[1,2]. Epoxy coatings(organic) are extensively used for the reason that, they have superior adhesion power onto any kind of substrates, versatility, elevated durability at all temperatures, and outstanding toughness. Epoxy coating on the metal structures creates a passive barrier between the corrosive media and steel substrate. Epoxy coating on the metal structures creates a passive barrier between the corrosive media and steel substrate. But, the corrosive agents (Cl-, O2, and H2O) penetrate through the microscopic cracks and cavities and reach the surface coating interface. This results in the deterioration of adhesion bonds and thereby, blistering of the coating occurs [3].

Recently, microencapsulated materials are proved to have the specific property of bringing back the corroded areas to normal. Wide nano-additives such as graphene and graphite were used as core materials to improve the corrosion resistivity of epoxy coatings. Among the various kinds of carbon materials, graphene oxide has paid unique attention due to its large surface area and superior chemical properties. The presence of various oxygenous functionalities, namely hydroxyls, carboxyls, and epoxides on its basal planes declines the mentioned interactions and makes them favorable for dispersion in polymers. However, due to intrinsic Van der Waals interactions[4,5], they result in poor exfoliation and dispersion in organic polymers. This major obstacle could be precluded by decorating graphene oxide sheets with facile functionalities. Microcapsules with modified graphene oxide were expected to enhance the physical properties of the epoxy system. Yu et al.,[6] improved the dispersion and corrosion protection activity by fabricating GO sheets with Al2O3 in the presence of 3-aminopropyltrimethoxysilane. Li et al.,[7] improved the anti-corrosion performance of silane composites by adding silanized graphene oxide. All the above-mentioned works suggest that the inclusion of additives onto GO sheets can only improve the passive barrier properties and could not heal the mechanical damages created in the coating structure, which is considered to be the main inadequacy of GO-epoxy composites. There is no work reported on the microencapsulation of modified GO sheets with superior adhesion bonds and dynamic corrosion mitigating performance.