Researchers at the University of Buffalo, working on research grants from the Army Research Office, have discovered a way of layering plastics that results in a material 14 times stronger than steel and eight times lighter. The layering technique is inspired by the way clams make pearls, and the final result is strong, light, but still slightly flexible armor.
A new lightweight plastic that is 14 times stronger and eight times lighter than steel may lead to next-generation military armor.
(Courtesy University of Buffalo)
The outer coatings of pearl are nacre, a structure of calcium carbonate that resembles interlocking bricks when viewed under a microscope. The researchers took ultrahigh molecular weight polyethylene, a souped-up plastic used in orthopedic devices, and layered it in a way similar to nacre.
The results are outstanding. Current body armor can contain up to 28 pounds of small arms protective inserts. The Kevlar plates used are about 80 percent of the weight of a steel plate of similar size. A UHMWPE plate of the same size would be about 12-13 percent the weight of a steel plate. That would put the plates needed for a large set of UHMWPE body armor at about 4 pounds instead of the 28 pounds for ceramic Kevlar armor.
Anyone who has worn 30 pounds of body armor and 50 pounds of additional gear while carrying an 8-pound weapon can tell you that shaving 24 pounds off the total load makes a huge difference. (Even though, in mortar sections, they’ll probably just make troops carry more ammo to make up the difference.)
And the inner layers of the armor deform to absorb the impact suffered by the outer layers, better protecting the target from the impact of the enemy’s shot.
82nd Airborne Division paratroopers work their way up a short slope while patrolling in Southern Afghanistan in 2012.
The total protection provided by the UHMWPE is so great that the researchers are considering its use in applications beyond body armor.
“The material is stiff, strong and tough,” said Dr. Shenqiang Ren, a professor in the Department of Mechanical and Aerospace Engineering, a member of University at Buffalo’s RENEW Institute. “It could be applicable to vests, helmets and other types of body armor, as well as protective armor for ships, helicopters, and other vehicles.”
The wide range of potential applications is partially thanks to the strength to weight ratio. But it’s also more flexible than other materials. This makes it easier to form the material into a variety of shapes for different uses.
“Professor Ren’s work designing UHMWPE to dramatically improve impact strength may lead to new generations of lightweight armor that provide both protection and mobility for Soldiers,” said Dr. Evan Runnerstrom of the ARO. “In contrast to steel or ceramic armor, UHMWPE could also be easier to cast or mold into complex shapes, providing versatile protection for Soldiers, vehicles, and other Army assets.”
And, with the addition of boron nitride, the material becomes a little stronger and much better at shedding heat. This would allow it to more rapidly cool off after being hit by enemy fire, giving it better protection against a second or third hit.
So it’s much lighter, stronger, and more adaptable than any armor you’re currently wearing.
But before you throw your SAPI plates off the roof in celebration, be aware that it will take time to create suitable manufacturing methods and products. The researchers used a 10-step process to create the small samples for their experiments and testing. It will be years before you and your vehicle are rocking this super-light armor.