Novel polyesters based on indazole moiety: Synthesis, characterization and applicability as efficient inhibitors for acidic X-65-steel corrosion

In this report, novel series of unsaturated polyesters Va-d and VIa-d containing indazole moiety were successfully prepared via interfacial polycondensation technique of indazole derivatives III and IV with different aromatic and aliphatic acid chlorides; isophthaloyl-, terephthaloyl-, adipoyl-, and sebacoyl chlorides. The prepared polyesters were categorized by elemental analyses, IR, H-1 NMR, Mass spectra, GPC, Thermogravimetric (TGA), X-ray analyses (XRD), and therefore the morphology was examined by scanning microscopy (SEM). They showed high thermal stability and different morphology structure. The corrosion protection performance of prepared polyesters Va-d and VIa-d on X65-steel in molar oil of vitriol was assessed using potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), and SEM. Electrochemical tests (EIS and PDP) displayed polymers could efficiently impede the X65-steel corrosion and acted as inhibitors of the mixed type. At the optimal dose of 150 mg/L, the protection capacities of Va-d and VIa-d polymers ranged from 86.9% to 97.8%. adsorption of Va-d and VIa-d followed the adsorption model of Langmuir isotherm. Surface morphology examination by SEM also revealed that Va-d and VIa-d polymers form an efficient block layer on the surface of X65-steel to separate the acidic solution.

Automated summary

A novel series of unsaturated polyesters containing indazole moiety were successfully prepared using interfacial polycondensation technique, showing high thermal stability and different morphology structure. These polyesters demonstrated strong corrosion protection performance on X65-steel in sulfuric acid solution, acting as efficient inhibitors of mixed type corrosion.