TECH/MATERIAL SPECIAL...A paper thin material to stop bullets

A paper thin material to stop bullets 

Creation Of New Polymer Composite Can Help Make Thinner Protective Gear

Washington: Researchers have designed a new paperthin bullet-proof super material which can self-assemble into alternating glassy and rubbery layers.
    The nanomaterial could translate into safety beyond vests. These advancements could accelerate progress on protective coatings for satellites and even jet engine turbine blades, researchers said.
    A team of mechanical engineering and materials scientists from Rice University and Massachusetts Institute of Technology (MIT) created special materials that were able to stop bullets in the lab.
    The type of material, called a structured polymer composite, can actually selfassemble into alternating glassy and rubbery layers, the Discovery News reported.
    While performing ballistic tests on the material at MIT’s Institute for Soldier Nanotechnologies, the 20-nanometre-thick layers were able to stop a 9-millimetre bullet and seal the entryway behind it, according to a Rice University. However, one of the challenges to making thinner and lighter protective gear is being able to test the materials effectively in the lab.
    Researchers need to know precisely why those nanolayers are so good at dissipating energy, but analysing the polymer can take days.
    The MIT-Rice team also came up with an innovative testing method, where they shot tiny glass beads at the material. Although the beads were only a millionth of a meter in size, they simulated bullet impacts.
    Under a scanning electron microscope the material’s layers look like corduroy so the projectile impact can be seen clearly. The researchers deduced that a projectile hit their target 2,000 times faster than an apple falling one meter hits the ground, but with a million times less force. Because the projectile’s impact area is so concentrated, however, the impact energy is more than 760 times greater.
    “After the impact we can go in and cross-section the structure and see how deep the bullet got, and see what happened to these nice parallel layers,” Rice materials scientist Ned Thomas said. “They tell the story of the evolution of penetration of the projectile what mechanisms, at the nanoscale, may be taking place in order for this to be such a highperformance, lightweight protection material.” AGENCIES

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