Bulletproof T-shirts

Combine cotton and boron, and you get a T-shirt that can stop a bullet

It’s a new take on the classic white T: University of South Carolina engineers have discovered a technique that involves melding a cotton T-shirt with boron, the third-hardest material on earth. With refinement, the product may provide a flexible, lightweight material that can be used in place of rigid bulletproof vests and body armour. Dr. Xiaodong Li, the USC engineer leading the research team and his colleagues discovered that the cotton fibres of a T-shirt turn to carbon when heated at 1,100° C under a stream of argon to prevent burning. When the shirt is then dipped in a boron solution, the two substances react to create boron-carbide fabric, a material made up of woven nano-fibres that are strong enough to stop a bullet.

In previous experiments, the nano-fibres would bunch together, but researchers solved this problem by using a T-shirt as a template. While stiffer than the original T-shirt, the boron-carbide fabric can still be worn comfortably because it retains some of the original garment’s elasticity. “We should be able to fabricate much tougher body armours using this new technique,” says Li.

The first truly bulletproof vest to permit mobility was made in 1969 of quilted nylon with steel plates, and was marketed to American law enforcement by Smith & Wesson. Then in the mid-’70s, DuPont introduced vests made of a woven synthetic fibre called Kevlar that could be concealed under clothing. There has been little advancement in the field of ballistic armour since then, which is why Li calls this most recent advance “a conceptual change in fabricating lightweight, fuel-efficient, super-strong and ultra-tough materials.”