Weathering degradation of a polyurethane coating

摘要

The degradation of polyruethane topcoat over a chromate pigmented epoxy primer was examined by atomic force microscopy (AFM), scanning electronic microscopy(SEM), X-ray photo-electron spectroscopy(XPS)and Fourier transform infra-red spectroscopy(FTIR)after the coated panels were exposed in a QUV chamber. It was found that upon QUV exposure, blisters formed on the topcoat surfaces during the initial phase of coating degradation. As a result of blister formation and subsequent breakage, coating gloss was lost before any pigments were exposed in the coating.