EFFECT OF PHOTODEGRADATION ON ATTENUATED TOTAL REFLECTANCE SPECTRA OF ORGANIC COATINGS.
NAVAL CIVIL ENGINEERING LAB PORT HUENEME CALIF
Pagination or Media Count:
Clear and pigmented films of various coating vehicles were irradiated in air with a mercury arc and with a xenon arc. Attenuated total reflectance ATR spectra were obtained before and after the irradiations in an attempt to find an accelerated test method for determining coating performance. The coatings included alkyd, vinyl-alkyd, partially hydrolyzed vinyl copolymer, vinyl copolymer, epoxy-amine, and epoxy-polyamide films. Although the mercury-arc irradiations produced considerable effects on the ATR spectra of clear vehicle films, the xenon-arc irradiations produced comparatively negligible effects. Whereas the observable effects of mercury-arc irradiations on pigmented films were less than on clear films, the reverse was true with the xenon-arc irradiations, which produced appreciable effects only on some of the pigmented films. These differences in results may be related primarily to the spectral distribution of the irradiating light and to the resultant differences in penetration and reflection within the film. ATR spectroscopy may prove to be useful in an accelerated method for determining deterioration in pigmented organic coatings, but it does not appear useful for clear films. Author
- Coatings, Colorants and Finishes