Inhibition of Chitosan and Its Derivatives Doped Polyanilines for Carbon Steel in 0.5 mol·L-1 HCl Solution

Chitosan and its derivatives doped polyanilines, including chitosan doped polyanilines (CTS-PANI), carboxymethyl chitosan doped polyanilines (CMC) and hydroxypropyl chitosan doped polyanilines (HPCS-PANI), were synthesized by chemical oxidation method. The products were characterized using Fourier transform infrared spectroscopy (FTIR). Their corrosion inhibition for carbon steel Q235 in 0.5 mol·L-1 HCl solution was studied by corrosion testing and electrochemical testing. The results show that the inhibition efficiency of eigenstate polyanilines and doped polyanilines first increased and then decreased with the increase of inhibitor content. When the inhibitor content was 50 mg·L-1, the inhibition efficiency reached maximum value. The order of inhibition efficiency for four kinds of inhibitor was presented as following: CMC-PANI>HPCS-PANI>CTS-PANI>PANI. The CMC-PANI had the best corrosion inhibition, with the highest inhibition efficiency of 91.9%.