Greener waterborne epoxy coatings with optimized UV-resistance

• Published in: Polímeros, ciência e tecnologia Vol. 34; no. 3
• Main Authors: Silva, Mauro Sergio da, Souza, Alana Gabrieli de, Rosa, Derval dos Santos, Valera, Ticiane Sanches, Wiebeck, Hélio
• Format: Journal Article
• Language: English
• Published: Associação Brasileira de Polímeros 01-01-2024
• Subjects: curing agent; epoxy coatings; weathering; yellowing
• ISSN: 0104-1428; 1678-5169
• DOI: 10.1590/0104-1428.20230133

Abstract The UV-resistance performance of waterborne epoxy coatings with different aminic-curable substances was evaluated to solve the widely known problem of poor weathering resistance of coatings. Samples were evaluated by color and gloss changes, FTIR, thermal properties, and macroscopic morphology. Results indicated that higher aminic values in curing agents degraded faster than lower aminic values (increases of ~3% in delta b and delta E between 5 and 20%). All samples showed a gloss variation varying between 40 and 70 G.U. FTIR and Tg indicated the resin degradation when using curing agents of unmodified aliphatic amine because of its rapid chemical degradation under a UV environment, as confirmed by microscopy images. The curing agents with aminic values between 200 and 300 KOH/g and the equivalent weight of amine hydrogen higher than 120 g/eq showed the best performance in epoxy coatings and good stability against accelerated aging, being promising options for future applications.