Fluoroethylene vinyl ether (FEVE) polyurethane coatings were synthesized to evaluate the effects of weathering on their long-term performance for military applications. FEVE coatings have the potential to limit the photooxidative effects that cause the degradation of traditional polyurethane films. However, we have found after 2000 h of accelerated weathering the films become extremely stiff and have the potential to delaminate from substrates. To mitigate this we have blended a soft macrodiol to improve flexibility. Coatings were subjected to two different accelerated weathering methods over 2000 h to simulate real world conditions: cycles of exposure to a xenon arc lamp, water spray, and darkness; or constant 77 °C and 95% relative humidity (RH). Dynamic mechanical analysis indicated that coating flexibility increased as the percentage of soft macrodiol increased post-weathering. Further, FTIR analysis indicated a decrease in weathering resistance as the macrodiol percentage increased in coatings subjected to the arc lamp. Minor degradation was observed in samples subjected to heat and humidity, yet surface analysis indicated a decrease in contact angle. These results suggests the mechanism of weathering induced of coating degradation is complex and likely different under separate conditions. As such, potential pathways for coating degradation under the different weathering conditions are discussed.

Mechanical stability of fluoroethylene vinyl ether polyurethane films blended with a soft macrodiol subjected to weathering

2019 Fall National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.