Session D40 - Poster Session I.
POSTER session, Monday afternoon, March 12
Exhibit Hall, Washington State Convention Center
Polyurethane film samples were exposed to different accelerated aging environments, including narrow-band irradiation from 340 and 313 nm UV sources, broadband irradiation from a xenon arc lamp, and elevated temperature without irradiation. The effect of oxygen and the influence of titania on free-radical formation were examined. Early stage radicals were detected by generating them in the ESR cavity at 77 K. A correlation between ESR and positron annihilation spectroscopy (PAS) data was observed, which indicates that free-radical-type chemical defects may be the cause of sub-nanometer physical defects. (Support by AFOSR and NSF is gratefully acknowledged.)