POLYAMINO-BENZOQUINONE POLYMERS - A NEW CLASS OF CORROSION-INHIBITORSFOR MILD-STEEL

A new class of corrosion inhibitors, namely, polyamino-benzoquinone (P AQ) has been synthesized and its inhibiting action on the corrosion of mild steel in 1N H2SO4 and 1N HCl has been investigated by various co rrosion monitoring techniques. A preliminary screening of the inhibiti on efficiency of the polymer was carried out by self corrosion studies . PAQ is found to behave better in 1N H2SO4 than 1N HCl. Potentiodynam ic polarization studies clearly reveal the fact that PAQ is a mixed-ty pe inhibitor. PAQ is able to reduce considerably the permeation curren t through the steel surface in both the acids. Changes in impedance pa rameters (R(ct) and C-dl) are indicative of adsorption of PAQ on the m etal surface leading to the formation of a protective film which grows with increasing exposure time. The adsorption of this polymer is also found to obey Temkin's adsorption isotherm in both acids thereby indi cating that the main process of inhibition is by adsorption. UV spectr al studies were also carried out to establish the actual mechanism of inhibition of corrosion.