[ cool new material . . . ]
THE WEIRD properties of a mysterious foam have been measured for the
first time. The US Air Force researchers who did the job say the foam
could replace several different types of material, including glass
fibre and aluminium honeycomb, in planes and spacecraft.
Called graphitic foam, it was first made at the US Air Force Research
Laboratory at the Wright-Patterson Air Force Base in Ohio. They melted
a liquid crystal polymer under pressure in an inert gas atmosphere,
forcing the gas to dissolve in the melt. When the pressure was
released, bubbles of gas formed inside the material, creating
foam. Heating this in an oxygen atmosphere formed graphite crystals,
which are extremely strong.
Researchers first tried to measure the foam's mechanical properties by
gluing strain gauges to it, but glue seeped into the foam and changed
its composition. Now the researchers at AFRL have built precision
equipment to carry out extensive tests, which showed that the foam has
three times the stiffness of aluminium honeycomb. And unlike
fibre-based composites and honeycombs, which are strong in only two
dimensions, the graphitic foam retains its properties in three
These properties mean it can perform several functions at once. For
example, in a space shuttle it could carry heat and electrical charge
from one part of the structure to another, and provide mechanical
From New Scientist magazine, 07 October 2000.
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