Plastic — in this case, polyethylene — is being credited for making body armor significantly lighter for U.S. troops.
I've noticed a few stories about the development in the past few months, most recently today's story from Stars and Stripes, Kevlar or plastic? New armor lighter, provides same protection.
The story explains how the Pentagon plans to roll out new, lighter weight body armor that's made from polyethylene, instead of the more familiar Kevlar. (For the record, they're both plastic. Kevlar is an aramid fiber. Polyethylene alternatives to Kevlar have been around for years.)
According to Seth Robson's story, the new gear weighs about 23 pounds, which is 25 percent lighter than what troops currently wear. The equipment has been undergoing field testing, and the Pentagon claims it is cheaper and offers the same level of protection as current body armor.
The military will start using the new gear in 2019.
Army Times reported on some of the new gear in February (Army to roll out better body armor, combat shirt in 2019), and its report has more detail on some of the components.
Finally, the blog Motherboard (The Pentagon Is Finally Designing Combat Gear for Women) noted that the new gear includes a version with specific new features for women. These include design improvements to protect women's reproductive organs, and to making the equipment more comfortable to wear without limiting the soldier's movement.