A study on the influence of silanized clay on the barrier, hydrophobic and mechanical properties of epoxy coated steel in natural seawater
Joseph Raj Xavier, Raja Beryl J, NARAYANAN RAVISANKAR
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.