Synthesis And Corrosion And Scaling Inhibition Of Polyacrylic Acid

It is a hotspot to study polymer corrosion inhibitors which are easy to form monolayer or multilayer compact protective films on the surface of substrates. They are high efficiency,lasting and environmental friendly compared with low molecular weight inhibitors.Different molecular weight polyacrylic acids have been synthesized in this paper. The structures of the synthesized polymers have been studied by IR analysis. And we determined the molecular weight of the polymers by Ubbelohde viscometer. The performance of polyacrylic acid as corrosion inhibitor for Q235 steel in 1M HCl solution and neutral water solution have been evaluated by weight-loss method. By potentiodynamic polarization method and electrochemical impedance spectroscopy method, the mechanism of inhibition process has been discussed. Furthermore its scale inhibition efficiencies for CaCO3 were investigated by static anti-scaling method. Finally we analyzed the mechanism of anti-scaling process.The weight-loss experiments results show that the PAAC exhibits ineffectual corrosion inhibition for Q235 steel in 1M HCl solution. At 40℃, with the concentration of 3125 mg/L , the inhibition efficiency is approximately 66.75%. when the temperature is above 70℃, corrosion process accelerates. In neutral water solutions, the PAAC shows nearly no corrosion inhibition for Q235 steel.On the other hand, the synthesized PAAC possesses good scale inhibition to calcium carbonate. At 80℃, with the concentration of 80mg/L, the scale inhibition efficiency reaches 96.7%. While at 60℃, with the concentration of 40mg/L, the scale inhibition efficiency is 99.3%.Polarization tests demonstrate that the polyacrylic acid is an anodic adsorption type corrosion inhibitor, which retards the anodic process of corrosion. The impedance diagrams show that all the electrochemical impedance spectroscopies are similar. This means that the PAAC does not change the anodic reaction process.