Abstract |
Erosion rate studies supported by attenuated total infrared reflectance (ATR) measurements and scanning electron microscopy (SEM) analyses provide a definitive technique for determining the effect of atmospheric pollutants on the performance of exterior coatings. This technique is based on the use of a gas controlled, Xenon Arc type Weather-Ometer. The other methods of testing that were investigated--tensile strength, gloss or sheen and surface roughness--provided considerably less consistent trends in data for either the 'short term' exterior exposure or the Weather-Ometer studies. Atmospheric pollutants at levels representative of a highly polluted industrial site (1.0 ppm SO2 or O3) were shown in Weather-Ometer studies to exert a significant adverse effect on the performance of specific coatings compared to the zero pollutant condition. The ranking of a coating in terms of erosion rates was also shown to be virtually independent of exposure to a pollutant type or level. Four paints were studied--oil house paint, latex and coil coatings, alkyd industrial paint, and automotive refinish. |