Anti-corrosion behaviors of corn-based polyols on low carbon steel rebar

Abstract

The extensive application of chloride-based deicing chemicals has resulted in significant corrosion-induced deterioration in transportation infrastructure and vehicles. The objective of this research was to investigate corrosion inhibition performance of two low-cost, environmentally safe, and non-toxic corn-derived polyols – sorbitol and mannitol – on ASTM A615 low carbon steel rebar. The polyols were each added to a traditional pavement deicer (23.0% sodium chloride by weight) at 1.0%, 2.5%, and 5% by weight replacements. The steel samples were exposed to a continuous flow of solution during an electrochemical experiment by both linear polarization resistance (LPR) and potentiodynamic polarization (PDP). In addition, solution analysis was performed using inductively coupled plasma-mass spectrometry (ICP-MS), and corrosion product characterization was examined by scanning electron microscopy. The results demonstrated that the incorporation of corn-derived polyols in the deicing solution reduced the corrosion initiation and that the degree of inhibition increased as the weight concentration increased from 0% to 5%. Following the Langmuir adsorption isotherms, it is posited that the inhibitors reduced the corrosion rate via adsorption onto the steel surface and allowed for a passive layer to form, which was supported by additional surface analysis. Thus, the outcome from this study will contribute to the search for a sustainable approach to mitigating the environmental impacts of chlorides and steel corrosion.