A self-healing MoS2/GO hybrid polyurethane-based coating with superior anticorrosion performance for Q235 steel

The application of conventional organic coatings as a method of surface protection for carbon steel materials is a widely adopted practice. Nevertheless, the protective capacity of the coating is limited by the occurrence of defects during the curing process and the rapid intrusion of acidic media. In this work, a self-healing anticorrosion hybrid coating, designated as MoS2-APTES-GO-PU, has been successfully fabricated on Q235 steel, which exhibits excellent protection in acidic oil well formation water. Molybdenum disulfide (MoS2) is grafted onto the surface of graphene oxide (GO), through a facile 3-aminopropyltriethoxysilane (APTES) hydrolysis method to forming a highly cross-linked three-dimensional network structure, which is homogeneously dispersed in self-healing polyurethane (PU). The incorporation of GO has been found to result in a labyrinth effect, which can be attributed to the extensive specific surface area. Furthermore, the uniform distribution of MoS2 on the surface can remarkably improve the anticorrosion properties. This phenomenon can be ascribed to the MoS2 effectively limiting the rapid galvanic corrosion between GO and substrates in acidic corrosive media. MoS(2)APTES-GO rectifies the phenomenon that APTES-GO depletes the dynamic hydrogen bonding groups in PU due to the abundance of active groups on the surface, thereby improving the self-healing ability of the coating. Additionally, the MoS2-APTES-GO maintains a stable chemical structure when subjected to acidic conditions own to the excellent chemical stability of GO and MoS2, which can effectively delay the rapid penetration of corrosive media. Based on the electrochemical tests, the corrosion current density of 0.4 wt% MoS2-APTES-GO-PU coating is reduced to 7.35 x 10-(11) A/cm(2 )from 1.03 x 10(- 8) A/cm(2) of pure PU coating and the self-healing efficiency reaches 1.98 x 10(7) Omega cm(2)/h. The current 0.4 wt% MoS2-APTES-GO-PU coating is self-healing and has favorable corrosion resistance for application in acidic environment.