Exploration of high corrosion resistance property of less hazardous pyrazolidine-based benzoxazines in comparison with bisphenol-F derivatives

The present work describes the design of nontoxic pyrazolidine bisphenol (PYBP)-based hydrophobic benzoxazine (PBz) matrices, in comparison with that of bisphenol-F-based benzoxazines, and investigates their efficiency toward corrosion protection on mild steel surfaces. The preliminary in vitro toxicity assay studies infer the nontoxic nature of PYBP. Data obtained from thermal and surface studies indicate that the PYBP-based PBzs possess higher thermal stability than those of bisphenol-F benzoxazines. Observations from SEM images suggest that the inherent hydrophobic nature was due to the formation of rough surfaces. The corrosion studies of the specimens were carried out using open-circuit potential, electrochemical impedance spectroscopy, and potentiodynamic polarization. Among the mild steel specimens, coated with different benzoxazines, the poly(PYBP-oda)-coated specimen was found to be less aggressive toward corrosion showing 90% efficiency and charge transfer resistance (Rct) of 381 kΩ cm2. Thus, data obtained from different studies suggest that the PYBP-based benzoxazines can be used as a better coating material for steel and steel products against corrosion.