When 9:00 AM - 10:30 AM Nov 16, 2007
Where 1670 CSE
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The Science Behind Automotive Painting

Mark Nichols, Ford Motor Company

Automotive painting has evolved over decades to the point where it is now a complex, highly engineered process requiring knowledge from organic chemistry, fluid dynamics, rheology, and color science. In addition, photochemistry plays a key role in two areas of paint technology: UV curing and long-term weatherability. Studies within our group have demonstrated the advantages of UV curing in both traditional free radical chemistries and in novel, base-catalyzed thiol compositions, where radical scavenging by oxygen is eliminated. Matching the spectral output of the curing source to the absorption profile of the photoinitiator and UV stabilizer has also been shown to improve the curing rate and film properties. During long-term weathering, exposure to UV radiation has a deleterious effect on coatings by inducing free radical driven photooxidation. Accelerating this degradation in the laboratory has proven challenging due to the difficulty in artificially matching the spectral output of the sun and in properly balancing other environmental variables. Experiments and modeling aimed at understanding the competing degradation mechanisms occurring during weathering will be discussed. A brief overview of the automotive painting process will proceed the more detailed research discussion.