copv-carbon-nanotube-nasa

This composite overwrapped pressure vessel (COPV) recently became the first carbon nanotube-based structural component flight tested by NASA. Photo Credit: NASA

That was, until Merrimack, N.H.-based manufacturer Nanocomp starting producing carbon nanotube-based yarns and fibers on a large enough scale to be incorporated in a structural application. Meador says his team at NASA worked with Nanocomp to tailor the mechanical and tensile properties of Nanocomp’s products, which could act as a drop-in replacement for components made with traditional CFRP.

The team opted to use a modified filament winding process that involved lining the outside of the COPV with the nanotube-based fibers because the diameter of the fibers was so much smaller than conventional carbon fibers. A COPV, Meador says, is dominated by tensile properties and would therefore be a good demonstration of the nanotubes’ potential.

Meador says his team was able to achieve its main goal of the flight test, which was to use the carbon nanotube-based COPV as a “gas storage bottle” for a cold gas structure system.

“[The COPV] did exactly what we expected it to do,” Meador says.

NASA is currently doing post-flight testing to assess whether the flight had any impact on the mechanical properties of the COPV. So far, the biggest thing Meador has been surprised by is that conventional carbon fiber composites “behave according to the rule of mixtures,” whereas carbon nanotube composites do not.

“We found that the strength of the [nanotube] composite was actually better than the strength of the fiber reinforcement, and that’s not what you see in conventional carbon fibers,” Meador says.

The Disrupter: R3FIBER Recycling Technology

Broader Implications: The potential to recover and reuse fibers from end-of-life composites.

There’s a big push within the composites industry to develop scalable recycling methodologies. One of the solutions that’s received lots of press is Thermolyzer technology from CHZ Technologies, which you can read about online at www.compositesmanufacturingmagazine.com. But other companies are working on composite recycling, too, including a start-up whose name says it all – Thermal Recycling of Composites (TRC).

TRC created the R3FIBER technology to recycle wind turbine blades and other composites at the end of their serviceable lives and obtain high-quality fibers, energy and fuels. “We’ve focused on recycling of composites due to the huge quantity of waste that’s already been dumped into landfills and because of the growing use of [FRP] materials, which are increasing nine to 12 percent every year,” says Oriol Grau, CEO of the Barcelona-based company.