Since World War I, the vast majority of US combat casualties had been caused by explosions. Today, most soldiers wear a heavy, bullet-proof vest to protect their torso but much of their body remains exposed to the indiscriminate aim of explosive fragments and shrapnel.
Now, Harvard University researchers, in collaboration with the US Army Combat Capabilities Development Command Soldier Center (CCDC SC), have developed a lightweight, multifunctional nanofiber material that can protect wearers from both extreme temperatures and ballistic threats. The research was published Monday in the journal Matter.
"When I was in combat in Afghanistan, I saw firsthand how body armor could save lives. I also saw how heavy body armor could limit mobility," said Kit Parker, professor of Bioengineering and Applied Physics at Harvard's School of Engineering and Applied Sciences, and a lieutenant colonel in the United States Army Reserve in a report published on Harvard's website.
"As soldiers on the battlefield, the three primary tasks are to move, shoot, and communicate. If you limit one of those, you decrease survivability and you endanger mission success," he explained.
"Our goal was to design a multifunctional material that could protect someone working in an extreme environment, such as an astronaut, firefighter or soldier, from the many different threats they face," said co-author Grant M. Gonzalez.
In order to achieve this practical goal, the researchers needed to explore the tradeoff between mechanical protection and thermal insulation, by mixing Kevlar and Twaron, two commercial products used extensively in protective equipment. Both products have a highly aligned crystalline structure and a high thermal insulation.
The researchers combined the polymer of one of those products with a low-density aerogels to make long, continuous fibers with porous spacing in between.
"In this system, the long fibers could resist a mechanical impact while the pores would limit heat diffusion. This fact was proved by scientific experiments," said Gonzalez.
