Work

Tannic acid loading into polyurethane and epoxy coatings: Active corrosion protection of AA2024 alloy

Year: 2025

Type: article

Abstract: Driven by the recent discovery of tannic acid (TA) as an effective green corrosion inhibitor for AA2024 alloy, this study evaluates its suitability as an additive for epoxy (EP) and polyurethane (PU) coatings, both through direct addition and by immobilization into layered double hydroxides (LDH-TA). LDH-TA was characterized by XRD, FTIR, and UV-visible spectrophotometry. Also, its anticorrosion performance was evaluated using EIS. The results show that the direct addition of TA to EP and PU coatings reduces their barrier properties, whereas incorporating LDH-TA into the polyurethane matrix provides superior corrosion protection compared to the epoxy coating. Therefore, LDH-TA-loaded PU coating (PU-LDH-TA) was further characterized through rheology analysis, surface characterization, release studies, and electrochemical techniques (EIS and SVET). The findings indicate that upon coating defects, tannate anions released from the polyurethane coating form a protective Al/tannate-rich hydroxide layer at the defect site. Thus, PU-LDH-TA demonstrates effective active corrosion protection in saline media, while maintaining the structural integrity of the coating.

Source: Surfaces and Interfaces

DOI: 10.1016/j.surfin.2025.106800

Authors: Rubén del Olmo, Cristina Neves, Alexandre Bastos, Raúl Arrabal, João Tedim

Institutions: University of Aveiro, Universidad Complutense de Madrid

Language: English

Topic: Corrosion Behavior and Inhibition

Subfield: Materials Chemistry

Field: Materials Science

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $2,670