Carbon Nanotubes Provide Reinforcement to Composites Instead of Merely Filler

The use of carbon nanotubes in composite resins as a filler didn't really take full advantage of their structural strength...a new manufacturing technique has changed that

2 min read
Carbon Nanotubes Provide Reinforcement to Composites Instead of Merely Filler

I have at times made out the use of carbon nanotubes in fillers for composite resins as much a marketing ploy as it was a structural improvement.

It seems researchers of a joint research project between Applied NanoStructured Solutions LLC (ANS, Baltimore, Md.), a Lockheed Martin subsidiary, and Owens Corning (Toledo, Ohio) were not altogether satisfied either with just using carbon nanotubes in these fillers.

The researchers were frustrated that resin loading of the carbon nanotubes was limited to little more than 3% or else the filler would become to viscous. So instead they started to look for ways of using carbon nanotubes in reinforcements rather than resins.

Back in 2007 when they embarked on this project they were looking to develop a way to incorporate nanoparticles directly into the fibers themselves. Now they have done that and also managed to do it in a way that it can be dropped into composites processors.

“We have developed a way to grow carbon nanostructures on fabrics,” Dr. Tushar Shah, ANS’ chief technology officer, is quoted as saying in the article from Composites World. “We’re not making CNTs and then transferring them,” he clarifies. “This is a continuous, direct growth process, directly onto the reinforcing fibers.”

The first application area being targeted is in electronics for electromagnetic interference (EMI) shielding. But that is really just a starting off point.

Because the composites developed with this process exhibit an inherent conductivity they are likely strong candidates for structural health monitoring (SHM) applications in which the material itself could serve as an in situ nanosensor in “smart” body armor.

If this industrial partnership is successful in getting these composites into more products, I think my reflex to scoff at the use of carbon nanotubes in them will have been cured.

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3D-Stacked CMOS Takes Moore’s Law to New Heights

When transistors can’t get any smaller, the only direction is up

10 min read
An image of stacked squares with yellow flat bars through them.
Emily Cooper

Perhaps the most far-reaching technological achievement over the last 50 years has been the steady march toward ever smaller transistors, fitting them more tightly together, and reducing their power consumption. And yet, ever since the two of us started our careers at Intel more than 20 years ago, we’ve been hearing the alarms that the descent into the infinitesimal was about to end. Yet year after year, brilliant new innovations continue to propel the semiconductor industry further.

Along this journey, we engineers had to change the transistor’s architecture as we continued to scale down area and power consumption while boosting performance. The “planar” transistor designs that took us through the last half of the 20th century gave way to 3D fin-shaped devices by the first half of the 2010s. Now, these too have an end date in sight, with a new gate-all-around (GAA) structure rolling into production soon. But we have to look even further ahead because our ability to scale down even this new transistor architecture, which we call RibbonFET, has its limits.

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