A study on the influence of silanized clay on the barrier, hydrophobic and mechanical properties of epoxy coated steel in natural seawater

Abstract

ABSTRACT Diethoxy(3-glycidyloxypropyl) methylsilane (GPMS), a surface modification agent, is used to give halloysite nanoparticles a hydrophobic behaviour and improve their ability to disperse in epoxy polymers (EP). Surface roughness and hydrophobicity (WCA: 144°) are both quite high in EP-GPMS/Clay coatings. The corrosion behavior of coated steel surfaces was investigated using electrochemical methods. The EP-GPMS/clay nanocomposite coating was shown to have about 63 times higher coating resistance than the EP coating. The EP-GPMS/Clay displayed better coating resistance (6687.71 kΩ.cm2) and a lower corrosion current density (4.25 μA/cm2) than plain epoxy (1.01 kΩ.cm2; 287.21 μA/cm2) even after prolonged exposure to the electrolyte, according to electrochemical studies. Compared to the pure EP (0.0599 mm/year), the EP-GPMS/clay coated sample had the lowest corrosion rate (0.0017 mm/year). According to SECM data, at 15 d of immersion, the Fe dissipation at the surface of the EP-GPMS/Clay coating (2.6 nA) is much smaller than the plain EP (14.7 nA). Additionally, the EP-GPMS/Clay showed enhanced adhesive properties. The EP with silanized clay offers an outstanding oxygen and water repellent, hydrophobic, and barrier properties. Due to the environmental safety of clay/silane, this kind of coating might be employed as a workable coating substance for industrial applications.