Modacrylic fiber is inherently flame resistant. Although it burns when directly exposed to flame, it doesn't melt or drip and is self-extinguishing when the flame is removed. Modacrylic is widely used in high performance protective clothing, such as firefighting turnout gear, because flame resistance is combined with other desirable textile properties such as durability and good hand feel.

Modacrylic fiber is chemical resistant. It retains its strength in concentrated acid/alkaline environments, which is useful for certain types of industrial filtration. Modacrylic is also on the extreme negative end of the triboelectric scale, and when combined with another more positive fiber such as polypropylene, results in a triboelectric media with improved filtration efficiency.