PREDICTING COATING DURABILITY USING CHEMICAL METHODS

This paper describes recent advances in the analysis of chemical degradation that occur during weathering which allow for improvements in the prediction of the durability of coatings. The basic weatherability test protocol involves the use of actual outdoor exposures and mildly accelerating 'near-ambient' laboratory exposures. Physical property changes are combined with FT-IR measurements of coating chemical degradation to evaluate the acceleration factor for a given test and coating. Measurements of hydroperoxide concentration are used to evaluate coating formulation changes and to control coating quality. These measurements are also shown to be useful for understanding degradation mechanisms and developing improved coatings.