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Polymers are very large molecules that are formed by the combination of a number of
relatively small molecules called monomers. Polymers can be made from inorganic or
organic molecules. They may have different forms—chain like as in polyethylene, or
sheet like as in quartz. The synthetic polymers are long chain organic molecules whose
dimensions could approach 10Å as compared to the simple molecules having dimensions
of 10Å. In the last two decades, there has been an increase in the use of polymeric compounds
as corrosion inhibitors. Inhibition of corrosion of iron in Hydrochloric acid (HCl) medium
was studied using Polyaniline and Poly ethoxy aniline as corrosion inhibitors by
Sathyanarayanan et al. (1992).
Epoxidized fatty materials with aromatic amines were found very useful for the
mitigation of corrosion of mild steel in HCl (Putilova et al., 1960). For iron, poly vinyl
pyrrolidone having a molecular weight of the order of 10,000 to 40,000 was an inhibitor of corrosion of a low carbon steel in Phosphoric acid (Jianguo et al., 1995). A water-soluble
melami e-formaldehyde resin was developed (Joshi and Srivatsava, 1989) and the film
formed in higher concentrations of HCl afforded lower protection.
Benzimidazole derivatives (Golozar et al., 2009) were found to be effective inhibitors
in 1N HCl and offer more than 95% inhibition. Polyethoxyaniline, Pectine (P), Carboxy
Methyl Cellulose (CMC), Poly Vinyl Alcohol (PVA), Poly Ethylene Glycol (PEG),
Polyacrylic Acid (PAA) and Sodium poly acrylate (NaPA) in the concentration range of
0.02 to 0.2 gm.dm–3 were found to the effective inhibition of corrosion of iron in in HCl,
Perchloric acid (HClO4) and Sulfuric acid (H2SO4) solutions (Sayed, 1996). Polyaminobenzoquinones
(PAQ) inhibited the corrosion of mild steel in 1N H2SO4 and 1N HCl
solutions. They strongly absorbed on the active sites and formed a protective film formed
affected both the anodic and cathodic reactions (Muralidharan, 1998). The corrosion of
mild steel in 1N H2SO4 and 1N HCl solutions was inhibited by polyamide macrocyclic
compounds. Polymers of acrylamide with specific polar end group, namely, Thiomalic
acid, have been synthesized, characterized and evaluated for their corrosion inhibition
property for mild steel in acids. The inhibition efficiency was found to depend on the
polyacrylamide backbone length (Sathyanarayan et al., 1992). Poly (4-vinylpyridene poly-
3-oxide ethylene) was investigated as inhibitor for Armco iron in H2SO4. The observed
99% inhibition was due to adsorption, and the adsorbed molecules obeyed Frumkin
isotherm (Abed et al., 1999). Commercially available water-soluble acetylene black II
which has a structural similarity to polyaniline proved to be a good inhibitor for iron
under acidic conditions (Sathyanarayan and Balakrishnan, 1994). Amin et al. (2011) have
studied the rate of corrosion control of ASTM A213 grade T22 boiler steel in HCl solution
using Serine as safe inhibitor .
Inhibition of corrosion of mild steel in acidic medium using polymers and synergistic
halide additives is presented by Umoren et al. (2008). Studies on the inhibitive film
protection of water soluble on mild steel are presented by Joshi and Srivatsava (1989).
The inhibition action of polyvinylpyrrolidone and polyethylenimine for copper in aerated
H2SO4 was studied through electrochemical and Surface Enhanced Raman Spectroscopy
(SERS) experiments by Schweinsberg et al. (1996). Synthesis and characterization of
polystyrene/polyacrylamide block polymers having water-soluble and amphiphilic
properties have been reported by Tianru et al. (1993). Silverman et al. (1995) studied the
influence of pH on the inhibition of corrosion of steel in HCl by polyascorbic acid by
weight loss and Alternating Current (AC) impedance measurements. Muralidharan et al.
(1995) have investigated the utility for the corrosion of quinone as an inhibitor for the
corrosion of mild steel in acidic solution. Water-soluble polymers and copolymers by
interaction of polyelectrolytes with formamide was studied by Sayed (1996).
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