Three accelerated aging tests including the cyclic corrosion, intermittent condensation, and ultraviolet irradiation as well as an outdoor exposure test are performed on polyurethane coatings to investigate a quantification method for assessing the life of coatings. Rust did not occur in the 6-months accelerated test and the 12-months outdoor exposure test. However, the urethane bond of the coating surface was decomposed by the ultraviolet irradiation, and this behavior consisted with the outdoor exposure test. The ultraviolet irradiation primarily accounts for coating degradation in the environment. It was also found that decrease in contact angles are associated with that molecular changes on the surface. The contact angle showed a better correlation with the decomposition of urethane bonds on the surface than the specular gloss. An EIS measurement model for capturing degradation in the coating is also examined. Future work will involve heavily degraded samples to assess data reproducibility and to establish a degradation quantification method capable of reproducing the behaviors of different environments.

Subject
Circuits, Electrochemical impedance spectroscopy, Decomposition, Coatings, Irradiation, Condensation, Surfaces, Coating degradation, Polyurethane coatings, Urethane, Specular gloss, Aging, Samples
Keywords:
polyurethane coating, accelerated test, outdoor exposure test, FT-IR, EIS, contact angle
© 2021 Association for Materials Protection and Performance (AMPP). All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise) without the prior written permission of AMPP. Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
2021
Association for Materials Protection and Performance (AMPP)
You do not currently have access to this content.