Effect of Piperazine Functionalization of Mesoporous Silica Type SBA-15 on the Loading Efficiency of 2-Mercaptobenzothiazole Corrosion Inhibitor

This work intends to study the effect of functionalization of SBA-15 on the loading and release behaviors of 2-mercaptobenzothiazole (MBT). SBA-15 mesoporous silica was first synthesized and functionalized by a postgrafting method using a piperazine silane coupling agent. Then, SBA-15 was loaded with MBT as a corrosion inhibitor. Various characterizations demonstrated that MBT was successfully encapsulated into the interior nanochannels of nanocontainers. Furthermore, the release study results revealed that the modified sample liberated MBT up to 17 times of the unmodified sample. Assessment of the electrochemical behavior of steel in NaCl solution containing the released inhibiting moieties indicated that the presence of MBT resulted in the formation of a more compact layer of corrosion products with more fine particles. Moreover, the MBT molecules were found to be mixed-type corrosion inhibitors. It was found that functionalizing by piperazine improved the inhibition efficiency of MBT-loaded samples. The trend and magnitude of impedance of specimens coated by the artificially scratched epoxy silicone revealed the role of the inhibitors desorbed from the functionalized SBA-15 in the polymer film active corrosion protection properties.