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.  Non-pigmented and 10 vol% carbonyl iron pigment (CIP) coatings were subjected to two different accelerated weathering methods over 2000 h in an attempt to mimic real world conditions: cycles of exposure to a xenon arc lamp, water spray, and darkness; or constant 77 °C and 95% relative humidity (RH).  FTIR analysis of the amide-II linkage and carbonyl band indicated that minimal degradation of FEVE coatings occurred through 2000 h of exposure to both conditions.  However, increased stiffness and T<i><sub>g</sub></i> via dynamic mechanical analysis suggested degradation of the polymer matrix.  Further, gravimetric measurements demonstrated a significant mass loss over initial 500 h, which was unchanged over the remaining 2000 h.  Disagreement between IR and mechanical analysis suggests the mechanism of weathering induced degradation of the coatings is complex and likely different under separate conditions.  As such, potential pathways for coating degradation under the different weathering conditions are discussed.

Evaluation of fluoroethylene vinyl ether polyurethane films for improved durability to weathering

2019 Spring National Meeting

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