Study on the Self-Repairing Effect of Nanoclay in Powder Coatings for Corrosion Protection

Authors

Marshall S. Yang, Western UniversityFollow
Jinbao Huang, Western University of Health Sciences
Hui ZhhangFollow
James Noel, Western UniversityFollow
Yolanda S. Hedberg, Western UniversityFollow
Jian Chen, Western UniversityFollow
Ubong Eduok, Western UniversityFollow
Ivan Barker, Western UniversityFollow
Jeffrey D. Henderson, Western UniversityFollow
Chengqian Xian, Western UniversityFollow
Haiping Zhang
Jesse Zhu, Western UniversityFollow

Document Type

Article

Publication Date

7-7-2023

Journal

Coatings

Volume

13

Issue

7

First Page

1220

URL with Digital Object Identifier

https://doi.org/10.3390/coatings13071220

Abstract

Powder coatings are a promising, solvent-free alternative to traditional liquid coatings due to the superior corrosion protection they provide. This study investigates the effects of incorporating montmorillonite-based nanoclay additives with different particle sizes into polyester/triglycidyl isocyanurate (polyester/TGIC) powder coatings. The objective is to enhance the corrosion-protective function of the coatings while addressing the limitations of commonly employed epoxy-based coating systems that exhibit inferior UV resistance. The anti-corrosive and surface qualities of the coatings were evaluated via neutral salt spray tests, electrochemical measurements, and surface analytical techniques. Results show that the nanoclay with a larger particle size of 18.38 µm (D50, V) exhibits a better barrier effect at a lower dosage of 4%, while a high dosage leads to severe defects in the coating film. Interestingly, the coating capacitance is found, via electrochemical impedance spectroscopy, to decrease during the immersion test, indicating a self-repairing capability of the nanoclay, arising from its swelling and expansion. Neutral salt spray tests suggest an optimal nanoclay dosage of 2%, with the smaller particle size (8.64 µm, D50, V) nanoclay providing protection for 1.5 times as many salt spray hours as the nanoclay with a larger particle size. Overall, incorporating montmorillonite-based nanoclay additives is suggested to be a cost-effective approach for significantly enhancing the anti-corrosive function of powder coatings, expanding their application to outdoor environments.

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