Long-Term Environmental Aging of Polymer Composite Coatings: Characterization and Evaluation by Dynamic Mechanical Analysis

Fluorinated polyurethanes (FPUs) and their composites are promising new barrier materials with a broad range of applications. In particular, they are widely used as effective hydrophobic coatings that perform well under prolonged environmental exposure. Despite their extensive use, the behavior of FPU coatings under specific climatic conditions remains insufficiently studied. In this paper, dynamic mechanical analysis (DMA) is employed to evaluate the structural, mechanical, and relaxation evidence of climatic aging for paint-and-varnish coatings, which protect the surfaces of metallic alloys and polymer composites. Special knowledge of structural and physical–mechanical properties—such as a glass transition temperature (Tg), elastic moduli (E′ and E″) in both glassy and elastic states, degree of crosslinking, and other features relevant to coatings designated for climatic impact prevention—can be reliably obtained by the DMA technique. Along with previously published data, the currently obtained results for FPU have been analyzed for a long time (three years) of exposure in a wide range of climatic regions in Russia.