Kevlar is a registered trademark of DuPont for aramid organic fiber. This kind of fiber is a reinforced fiber after glass fiber, carbon fiber and boron fiber, which was first industrialized by DuPont. The tensile strength of this fiber is four times that of ordinary organic fiber, and its modulus is nine times that of polyester fiber. Because Kevlar brand fiber has low specific gravity, its specific strength is higher than that of glass fiber, carbon fiber and boron fiber. However, its low compressive strength and shear strength and high water absorption limit its application in some aspects. Kevlar brand fibers are mainly used to make ropes, cables, spray-painted fabrics and body armor, instead of glass fibers, they are wound into combustion chamber shells of large solid rocket engines, and are also used as tire cords in large quantities, which can withstand the high temperature of 150℃ ~ 160℃. Another important application of Kevlar brand fiber is to replace carcinogenic asbestos as a reinforcing material for brake pads, gaskets and clutch linings of various brakes.

It took the United States six years and 2.5 million yuan to develop a helmet made of aramid organic fiber, thus ending the era of the famous "helmet" as a symbol of the US Army. This helmet only weighs 1.45 kg, and its bulletproof performance is improved by 33% compared with the original standard helmet. At the same time, this new helmet is closer to the head and the user feels more comfortable.