Acrylic coating incorporated with lawsonia inermis as a green additive for marine application
Mohammad Fakhratul Ridwan Bin Zulkifli

Faculty of Ocean Engineering Technology and Informatics, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia

Abstract

Plant based materials have been investigated as corrosion inhibitor due to its wide availability. The essential component of plant based materials is its environmental friendly which contributes to the development of green corrosion prevention materials. In this study, Lawsonia inermis or also known as henna was extracted and incorporated as an additive into an acrylic coating. Newly formulated coating was tested by using XRD and DSC and the finding demonstrates that the increment of crystallite size in acrylic coating incorporated with Lawsonia inermis has limited the close pack structure which consequently increase free volume and reduce the glass transition temperature (Tg) of the coating. Open circuit potential (OCP) demonstrates that acrylic coating incorporated with Lawsonia inermis has a uniform potential due to passivation of electrode. Electrochemical impedance spectroscopy (EIS) shows that AC0.04g has the highest coating resistance (Rc) and lowest coating capacitance. Elevation in temperature has caused a coating deterioration for all coatings. Dielectric study reveals that acrylic coating incorporated with Lawsonia inermis has lower dielectric constant value indicates that there is a lesser water uptake and decrease in ionic conductivity. Tafel polarization test shows that the corrosion potential (Ecorr) of acrylic coating incorporated with Lawsonia inermis has shifted to the noble potential and record a decrease in corrosion current density (icorr). The value of corrosion rate is the lowest for AC0.04g while the polarization resistance shows the highest value. Morphology study via SEM shows that AC0.04g has a greater coverage Lawsonia inermis in the coating.

Keywords: Acrylic coating- corrosion- lawsonia inermis- electrochemical- optical

Topic: Aquatic Pollution and Ecotoxicology