Abstract
The inhibitive action of some poly (4-vinylpyridine-g-polyethylene-oxide) in three degree of quaternisation 5%, 15% and 45%, (P4VPPgOE) (g=136), against the corrosion of iron in 1M hydrochloric acid (HCl) has been studied at 298 K using weight loss measurements, potentiodynamic polarisation, and impedance spectroscopy (EIS) methods. Results obtained shows that (P4VPPgOE) (g=136) in degree of quaternisation 5%, is the best inhibitor and its inhibition efficiency increases with the increase of concentration of inhibitor to attain 100% since 5*10-7M. Polarisation measurements show also that the compound acts as a mixed-type inhibitor and were adsorbed on the iron surface according to the Langmuir adsorption isotherm model. E (%) values obtained from various methods used are reasonably good agreement. The temperature effect on the corrosion behaviour of iron in 1M HCl without and with the inhibitor at 10-6M was studied in the temperature range from 298 to 338 K, the associated activation energy have been determined and proved that the adsorption is a spontaneous process.