Corrosion Inhibitors for Carbon Steel using some Amide Resins derived from Waste Water drink Bottles

Abstract

Two amide resins, (bis-(2-hydroxy ethylene) terephthalamide) BHETA, and N1,N1,N4,N4 -tetra -(2-hydroxyethyl)-terephthalamide) THETA were prepared from reaction of waste water bottles (PET) with Monoethanolamine (MEA) and  diethanolamine (DEA) respectively using  microwave oven, (power less or equal to 600 w ) for 20 minutes. The products were characterized by FTIR spectroscopy then evaluated as corrosion Inhibitors for Carbon steel in 0.1 M HCl at different temperatures using Taffel plots and Electrochemical Impedance Spectroscopy (EIS) techniques. The obtained results showed that the Inhibition Efficiency (%E) increased up to 76% and 83% for BHETA and THETA respectively. The adsorption isotherm was investigated using Langmuir equation, and the obtained results confirmed the occurrence of  physico adsorption that occurs between the Inhibitor and surface of the metal, and the thermodynamic functions were calculated : Activation energy (Ea), Enthalpy (∆H̊_ads. ),  Free energy (∆G̊_ads. ) and entropy ∆S̊_ads. .  

The coating properties of 25% w\w of each BHETA and THETA with commercial acrylic paint were evaluated using EIS technique and showed that the efficiency of coating increased up to 89% and 93.6% when adding BHETA and THETA respectively.