After DuPont Kevlar rich fabrics are exposed to light the fiber’s surface begins a process called oxidation. As a para-aramid oxidizes it changes color: fabrics appear to get darker. This change in color is similar to the way a copper penny appears green after oxidation. Like a copper penny, the change in color from oxidation is normal and not indicative of degradation. The rate at which a DuPont Kevlar rich fabric darkens through oxidation depends on many factors. These include the fabric blend, fabric design, and most importantly the way in which the fabric or garment is stored (protected from light). Sometimes turnout gear will fully oxidize in a day, other times it takes weeks, and other times different panels of the garment will oxidize (darken) at different rates. One thing is certain: the entire garment will eventually oxidize and darken over time.
Fibrillation and oxidation are common to all outer shells and thermal liners rich with para-aramid fiber. It is important to understand the affects of fibrillation and oxidation to gain realistic expectations on fabric appearance, durability, and performance.