By Andrew Nusca
Posting in Aerospace
Researchers at Northwestern University have developed a new kind of disruptive fiber that could be tougher than Kevlar.
A team led by professor Horacio Espinosa engineered the high-performance fiber from carbon nanotubes and a polymer. Both strong and ductile -- usually it's a tradeoff between the two traits -- the fiber can absorb and dissipate large amounts of energy (and remain strong) before it fails.
The development promises improvements to an array of defense and aerospace applications, from bulletproof vests to parachutes to composite materials used in vehicles, airplanes and satellites.
To create the new fiber, researchers took carbon nanotubes -- carbon molecules shaped like cylinders, which are known to be among the strongest natural materials -- and added a polymer developed in conjunction with MER Corporation to bind the nanotubes together.
Normally, bundling nanotubes reduces their overall strength, as the tubes begin laterally slipping between each other. After spinning the combined material into yarns, the researchers used in-situ electron microscopy testing to examine the fibers top to bottom, from nano to macro scale.
The goal: understand with extremely high detail how tiny interactions affect the material’s performance.
What they found is that they developed a material that's stronger than Kevlar, with a higher ability to absorb energy without breaking. (One catch: Kevlar still has a higher resistance to failure.)
Moving forward, the researchers will continue to study the interactions of the nanotube bundles, searching for weak links to ferret out in the next go at a super-strong material. The team is considering several techniques, such as covalently crosslinking tubes within bundles using high-energy electron radiation, to engineer the results they want.
Their results were recently published in the journal ACS Nano.
Photo: DuPont's Kevlar
Dec 3, 2010