Effects of Pillaring Agents on Corrosion Resistance of Polybenzoxazine/Organoclay Nanocomposite Coatings with Intercalated Structure

Nowadays, a lot of efforts have been made to apply polybenzoxazine (PBz) as a novel coating material for protecting metals against corrosion, and outstanding performance were obtained based on these researches¹. Further enhancement and some functionality favorable to anticorrosion can also be achieved when PBz combine with other constituents. In our previous studies, PBz/organoclay composite coatings with intercalated and exfoliated structure were successfully prepared by incorporating organoclay modified by different pillaring agents into PBz matrix. Results of SEM and AFM show that samples with intercalated structure possess a relatively uniform surface opposed to the ones with exfoliated structure, especially at higher clay content. Furthermore, it was found that intercalated structure of organoclays in PBz matrix is of great help to improve corrosion protection ability of composite coating. In particular, the sample with 3 wt% organoclay I.44P provides the best performance with corrosion rate reduced by 3 and 4 orders of magnitude compared to PBz and bare MS, respectively². In this case, PBz/organoclay nanocomposite coatings with intercalated structure should be a promising coating material for corrosion protection.

Therefore, organoclays modified by two different pillaring agents were introduced in PBz coatings on mild steel. Composite coatings with intercalated structure were fabricated and characterized in terms of measurements to investigate their physicochemical properties and corrosion protection performance. The d-spacing values of organoclays were easily increased by blending with PBz monomer, which was evident from X-ray diffraction (XRD) patterns. Enhancement on corrosion resistance of PBz was also observed at all studied amounts. However, distinct degree of improvement for two systems were observed, which could be explained by the different interaction between PBz polymer chain and the pillaring agents involved.

1. “Changlu zhou, Zhong Xin.” “Polybenzoxazine-based coatings for corrosion protection," in "Advanced and Emerging Polybenzoxazine Science and Technology," Ishida, H.; Froimowicz, P. Eds. Elsevier, Amsterdam (2016).
2. Changlu Zhou, Xin Lu, Zhong Xin, Yangfeng Zhang. Intercalated polybenzoxazine/organoclay composites with enhanced performance in corrosion resistance.Journal of Coatings Technology and Research. 2016, 13(1): 63-72