Testing Accelerated Weathering Tests for Appropriate Weathering Chemistry: Ozone Filtered Xenon Arc

By J.L. Gerlock, C.A. Peters, A.V. Kucherov, T. Misovski, C.M. Seubert, R.O. Carter III, M.E. Nichols

FTIR spectroscopy has been used to follow the weathering chemistry of a HALS and UVA free poly-ester/urethane and a HALS and UVA free acrylic/melamine clearcoat cured on silicon wafers and subjected to exposure in Florida, Arizona, and in a number of accelerated weathering tests. All accelerated tests except EMMAQUA-NTW, ozone filtered xenon arc, and 3M Proprietary exposures distort the polyester/urethane’s weathering chemistry relative to its Florida and Arizona exposure weathering chemistry.

Distorted weathering chemistry was attributed primarily to spectral power distribution mismatch between artificial radiation and sunlight. Experiments were initiated with an ozone filtered xenon arc radiation source whose spectral power distribution matches sunlight with great fidelity in the 290-400 nm region.