Tertiary amin methacrylate base polymers use corrosion inhibitor

In this study, the inhibitive performance of novel synthesised water soluble poly [2-(dimethylamino)ethyl methacrylate] (PDMA), poly [2-(diethylamino)ethyl methacrylate] (PDEA), poly [2-(diisopropylamino)ethyl methacrylate] (PDPA) homopolymers and poly [2-(dimethylamino) ethyl methacrylate]-b- poly[methyl methacrylate] (PDMA-PMMA), poly [2-(diethylamino) ethyl methacrylate]-b- poly[methyl methacrylate] (PDEA-PDMA) and poly [2-(diisopropylamino)ethyl methacrylate]-b- poly [2-(dimethylamino)ethyl methacrylate] (PDPA-PDMA) of different molecular weight diblock copolymers – on the corrosion behaviour of AISI 304 stainless steel in 10-3 M HCl and double distilled water (pH=7,6) containing various concentrations polymers (1x10-2 M, 1x10-3 M, 1x10-4 M, 1x10-5 M) were investigated using potentiodynamic polarisation, electrochemical impedance spectroscopy (EIS), scanning electron microscopy(SEM), energy dispersive X-ray analysis (EDX), atomic force microscopy (AFM) and inductively coupled plasma optical emmision spectrometry (ICP OES). Polarisation curves indicate that all studied polymers were acting as mixed type inhibitors. All electrochemical measurements show that inhibition efficiencies increases with increasing inhibitor concentration. It's determined that the increase of inhibitor efficiency by concentration results from the adsorption of polymers to metal surface, and the adsorption fits to Langmuir adsorption equation. Adsorption equilibrium constant (Kads) and free energy of adsorption(Gads), which are thermodynamic parameters of adsorption has been calculated by benefiting from the drawn adsorption isotherms. The variation in inhibitive efficiency mainly depends on the type and the nature of the substituents present in the inhibitor molecule and also depends on the molecular weight of the inhibitors. The best inhibition in acidic medium show that VB84 homopolymer, in double distilled water show that VB207 diblock copolimer. Surface images obtained with SEM, EDX and AFM determined by verifying these results that inhibitors decrease the dissolution of metal, prevent the corrosion. Results of ICP-OES shows that metal dissolution increases in 10-3 M HCl medium than double distilled water.