Nanotube-laced epoxy: three times harder, far bett

brianwang writes "The longstanding promise of superfortified heat-conducting materials has become a reality. University of Pennsylvania scientists have determined that adding a relatively small number of carbon nanotubes to epoxy yields a compound three-and-a-half times as hard and far better at heat conductance than the product found in hardware stores. The researchers report their successful tinkering with the commonplace adhesive in the April 15 issue of the journal Applied Physics Letters. Led by Penn physicist Alan T. "Charlie" Johnson, the team created a composite of 95 to 99 percent common epoxy mixed with 1 to 5 percent carbon nanotubes, filaments of carbon less than one-ten-thousandth the width of a human hair. "These findings add considerably to carbon nanotubesí luster as possible additives to a variety of materials," said Johnson, an associate professor of physics and astronomy at Penn. "In addition to adhesives such as epoxy, we are looking at nanotube-based greases that might be used to carry heat away from electronic chips." Johnsonís group determined that epoxy doped with nanotubes showed a 125 percent increase in thermal conductivity at room temperature. "This is the first published report of enhanced thermal conductivity in a material owing to the addition of carbon nanotubes and the first demonstration of simultaneous thermal and mechanical enhancement of a real-world material," Johnson said. Epoxy is an attractive target for fortification with carbon nanotubes, Johnson said, because itís relatively easy to mix the minuscule filaments into it, and there are clear industrial benefits in a harder, better-conducting epoxy. Other scientists have attempted to fortify epoxy with carbon nanotubes, but Johnsonís group succeeded in dispersing the nanotubes more evenly. -net041502.php"

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