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American Today


Fox Tackling Greener Flame Retardants

By Mike Unger

Douglas Fox thinks he can make a greener flame retardant for plastic, and the Defense Department hopes he’s right.

The American University chemistry professor recently landed a $300,000 grant from the U.S. Air Force for equipment to assist in his quest to use cellulose to make a less-toxic flame retardant for polylactic acid–based plastic, an emerging material now used to make everyday items, such as the new compostable Sun Chips bags.

“Every plastic that you have has to have a flame retardant in it,” he said. “They removed flame retardants from TVs in Europe for a while, and the TVs started catching on fire. The best flame retardants they have right now are often very toxic. For decades they were using PCBs (polychlorinated biphenyls).”

Fox’s interest in the subject was sparked when he began using regular clay in fire retardants. But clay cannot be used solely, so Fox kept digging.

Cellulose is the most abundant organic molecule on the planet. It’s a structural type of molecule that makes up the base of most trees and plants.

“A lot of groups are trying to turn cellulose into fuel,” he said. “But we’re seeing how it improves mechanical properties of a polymer. How stiff will it be?”

Fox and his students will use three new instruments paid for by the government grant:

  • an extruder for preparing plastic
  • an X-ray diffractometer, which measures the crystalline structure of polymer
  • a dynamic mechanical analyzer, which measures the stiffness of the polymer

“I have a year to complete the project, but these instruments will be here and used by students for years to come,” Fox said.

Why is the Air Force interested in this project? The answer can be found in the skies above.

“Airplanes,” he said. “You want something very light, but you want something that’s durable and can withstand any of the shocks and vibrations up there. We use aluminum on airplanes, but there’s always a drive to make more plastic components so it’s lighter.

“When a plane crashes, there are usually not many survivors, but if there are, the number one cause of death after a survivable crash is fire. If you think about all the foams that are in there, it’s hitting with this huge amount of fuel. The flame retardant part itself is a great selling point for anything dealing with airplanes.”

Or potato chips.