small plans: nanotechnology for the building industry

Tuesday, April 18, 2006

Bomb-proof glass from transparent nanotubes

A team of researchers at the University of Toledo was trying to make stronger, lighter armor for Army vehicles when the Army came calling with a special plea: Can you drop that research program and instead concentrate on making glass that can withstand bullets and bombs?

According to a report in The Blade, insurgents in Iraq had figured out they couldn't always knock out an armored vehicle, but they could shoot through the windshield glass. Walter Roy, a materials engineer for the Army, made a special trip to the University of Toledo "to plead with us about this," said Arun Nadarajah, a professor in chemical and environmental engineering.

"It's one thing if someone gives you this idea abstractly, [and] abstractly asks, 'Would you consider doing this?' Then, probably not. But he came and made a very emotional pitch to the group," he said.

"I never met another government official like him. This guy was very different," Mr. Nadarajah said.

It was a dilemma for the research group of eight scientists and a dozen graduate students. For the previous two years, they'd been busy expanding their expertise on carbon nanofibers, which make a human hair look downright obese. Nanofibers were to be the key to creating strong, light armor. But there's a problem with taking that expertise and applying it to the Army's new request: You can't see through carbon. The UT group's work wouldn't transfer easily into making better windshields.

When Mr. Roy of the Army made his request, the UT group was in the second year of a three-year contract to find the right way to make strong armor. Each year of the contract, the group got $900,000 to work on armored vehicles.

Changing research "was not an easy decision," Mr. Nadarajah said. But, ultimately, the group decided that "this was important enough to take a stab at changing our course."

The researchers haven't had to scrap all of their carbon work. For instance, some changes they made to carbon nanofibers to increase material flexibility can be made in the transparent materials as well.

The group is experimenting with materials that become transparent at the nanoscale. They will blend these reinforcing nanofibers with polymers such as the polycarbonate used in eyeglasses to create Army-ready windshields.


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